The electrocardiogram reflects. ECG methods for studying the cardiovascular system What does a human electrocardiogram reflect?

Cardiac pathologies today are a fairly common and negative phenomenon. Each of us, feeling unwell, can consult a doctor for a referral for a heart cardiogram and then undergo appropriate treatment.

This painless procedure will allow you to learn about the condition of your heart and its possible pathologies. Early diagnosis of diseases will allow a specialist to prescribe effective treatment that will help you continue to enjoy yourself and lead your usual lifestyle.

Perhaps you have already encountered this diagnostic method, such as a cardiac cardiogram, and were unable to independently decipher the results. Don't worry, we will tell you how to do this and what diseases can be identified.

Cardiogram of the heart - general information

A cardiogram is a procedure that records various cardiac pathologies. Anyone who feels unwell can make such a diagnosis, even at home. Almost every ambulance has this device, so a cardiac cardiogram is often performed at home.

This method allows you to identify heart disease at an early stage, and deliver such a patient to the hospital department as soon as possible. If you approach deciphering the indicators of this study in a general way and from the position of a beginner, then it is quite possible to independently understand what the cardiogram shows. The more frequently the teeth are located on the cardiograph tape, the faster the myocardium contracts.

If heartbeats are rare, then zigzags on the cardiogram will be shown much less frequently. In essence, such indicators reflect the nerve impulse of the heart. In order to be able to carry out such a complex medical manipulation as deciphering a cardiac cardiogram, you need to know the meaning of the main indicators. The cardiogram has teeth and intervals, which are designated by Latin letters.

There are only five teeth - these are S, P, T, Q, R, each of these teeth shows the work of a certain department of the heart:

• P – normally should be positive, indicating the presence of bioelectricity in the atria;
• Q – in the normal state, this wave is negative, characterizing bioelectricity in the interventricular septum;
• R – shows the prevalence of biopotential in the ventricular myocardium;
• S – normally it is negative, indicating the final process of bioelectricity in the ventricles;
• T – during normal heart function it is positive and characterizes the restoration process of biopotential in the heart.

To understand which teeth are considered positive and which are negative, you should know that those teeth that point down are negative, and those that point up are positive. In order to record an electrocardiogram, twelve leads are used: three standard, three unipolar from the limbs and six unipolar from the chest.

It is the ECG that allows you to promptly notice trends in abnormalities in the functioning of the heart muscle and avoid further development of the disease. In fact, a cardiogram is the first thing a heart patient must go through on the path of diagnosis and development of a course of treatment and rehabilitation therapy.

The cost of a cardiac cardiogram is not so high compared to the significant preventive effect that is achieved as a result of its implementation. Performing a cardiogram in private professional clinics costs approximately 500 rubles or more.

The final price of a cardiac cardiogram depends on the pricing policy of the medical institution, the patient’s distance from the cardiologist in case of a doctor’s home call, as well as the completeness of the service provided. The fact is that often, in addition to direct research, doctors offer to develop on the spot an optimal strategy to combat possible deviations.

The ECG examination does not require any preliminary preparation or diet. Usually the procedure is performed from a lying position and takes very little time (up to 10 minutes).

In addition to the standard procedure for recording currents through the chest, there are several methods for conducting electrocardiography. A doctor at our clinic may recommend the following tests:

• daily (Holter) ECG monitoring – throughout the day the patient wears a small portable device that records the slightest changes in cardiac activity.

The advantage of the technique is that it is possible to track the functioning of the heart over a long period of time under normal living conditions: this helps to identify pathologies that are not detected during a single electrocardiography;

• ECG with stress - during the procedure, physical or medicinal stress can be used, as well as electrical stimulation if the ECG is performed using the transesophageal method.

The procedure is useful in that it helps to establish the exact cause of pain in the heart during physical activity, while at rest no abnormalities are detected.

An ECG is an absolutely safe and painless way to study cardiac activity. To carry it out, the patient must be placed on a couch, special electrodes must be placed in the required places, which will record the impulses. They are generated by the heart muscle during its work.

The tissues of the human body are, to one degree or another, conductors of electric current, so it can be recorded in different parts of the body. The study is carried out in twelve standard leads.

A cardiac cardiogram is not only performed for people with heart problems. This research is also carried out for healthy people. This procedure can determine:

• Heart rate.
• Regularity of pulse.
• The presence of acute or chronic damage to the myocardium.
• Metabolism problems.
• Causes of chest pain.
• The condition of the myocardial walls, their thickness.
• Features of the functioning of the embedded pacemaker.

Indicators of a normal cardiogram

Knowing how to decipher the ECG of the heart, it is important to interpret the results of the studies, adhering to a certain sequence. You need to pay attention first to:

• Myocardial rhythm.
• Electric axis.
• Conductivity of intervals.
• T wave and ST segments.
• Analysis of QRS complexes.

Interpretation of the ECG in order to determine the norm is reduced to data on the position of the teeth. The normal ECG in adults for heart rhythms is determined by the duration of the R-R intervals, i.e. the distance between the tallest teeth. The difference between them should not exceed 10%. A slow rhythm indicates bradycardia, and a rapid rhythm indicates tachycardia. The norm of pulsations is 60-80.

Based on the P-QRS-T intervals located between the teeth, the passage of the impulse through the cardiac sections is judged. As the ECG results will show, the normal interval is 3-5 squares or 120-200 ms. In ECG data, the PQ interval reflects the penetration of biopotential into the ventricles through the ventricular node directly to the atrium.

The QRS complex on the ECG demonstrates ventricular excitation. To determine it, you need to measure the width of the complex between the Q and S waves. A width of 60-100 ms is considered normal. The norm when deciphering an ECG of the heart is considered to be the severity of the Q wave, which should not be deeper than 3 mm and last less than 0.04.

The QT interval indicates the duration of ventricular contraction. The norm here is 390-450 ms, a longer interval indicates ischemia, myocarditis, atherosclerosis or rheumatism, and a shorter interval indicates hypercalcemia.

When deciphering the ECG norm, the electrical axis of the myocardium will show areas of impulse conduction disturbance, the results of which are calculated automatically. To do this, the height of the teeth is monitored:

• The S wave should normally not exceed the R wave.
• If there is a deviation to the right in the first lead, when the S wave is below the R wave, this indicates that there are deviations in the functioning of the right ventricle.
• A reverse deviation to the left (the S wave exceeds the R wave) indicates left ventricular hypertrophy.

The QRS complex will tell you about the passage of biopotential through the myocardium and septum. A normal ECG of the heart will be in the case when the Q wave is either absent or does not exceed 20-40 ms in width and a third of the R wave in depth.

The ST segment should be measured between the end of the S wave and the beginning of the T wave. Its duration is affected by the pulse rate. Based on the ECG results, the normal segment occurs in the following cases: ST depression on the ECG with permissible deviations from the isoline of 0.5 mm and elevation in leads of no more than 1 mm.

Indications for an electrocardiogram for adults:

• It is definitely worth doing a cardiogram of the heart if you suspect a disease of the “motor” or organs of the cardiovascular system and the first alarming symptoms appear: shortness of breath, pressing and squeezing pain in the chest, heaviness, tachycardia, edema, and others;
• a cardiogram can help prevent serious pathologies for those who are at risk of heart disorders (smokers, overweight people, hypertensive people, with a hereditary predisposition, as well as an annual examination for people over 40 years of age);
• upon the accomplished fact of detection of heart disease - behind the dynamics of the development of pathology and control over the situation.

ECG indications for children:

• A cardiogram of the child’s heart is performed for preventive examination in all children under 1 year of age;
• if there is a suspicion of congenital heart disease. Which can be judged by early symptoms;
• with possible acquired pathologies of the heart, as well as the involvement of the organ in the symptoms of disturbances in the functioning of other body systems.

An ECG examination is the first part of the diagnosis. The qualifications of the physician who interprets the research results are of paramount importance. The developed treatment strategy, and therefore a successful outcome for the patient, depends on the correct interpretation of the image of heart sounds.

To provide emergency care, private clinics provide the service of a cardiologist visiting the patient directly at home, as well as conducting EGC at home. In this case, you should only contact reliable clinics with a reliable reputation.

It also remains to remember that an ECG is an effective, but far from the only means of diagnosing cardiac pathologies. For a more accurate diagnosis, a stress ECG, echocardiography, pulse oximetry, a number of laboratory tests and other studies may be prescribed.

One of the main advantages of ECG is that the traditional procedure has no contraindications. Its implementation may be somewhat complicated if you have chest injuries, a high degree of hair growth, or severe obesity.

Data may also be distorted if you have a pacemaker. A stress ECG is not performed in some cases:

• in the acute period of myocardial infarction,
• for acute infections,
• aortic aneurysm dissection,
• worsening of heart failure, ischemia and hypertension,
• in the stage of decompensation of diseases of other body systems.

Before performing a cardiogram, the doctor will tell the patient about all the aspects of preparing for the study. What can cause incorrect readings on an ECG:

• consumption of any alcohol-containing drinks, as well as energy cocktails;
• smoking 3-4 hours before the procedure;
• excessive consumption of food 3-4 hours before the test. It is better to do a cardiogram on an empty stomach;
• strong physical activity the day before;
• emotional stress;
• use of medications that affect heart activity;
• coffee drunk 2-3 hours before the ECG.

Many people forget that deciphering a cardiogram can erroneously show the presence of pathologies, due to the experiences experienced by a person the day before or if the patient was late for the ECG and ran to the office.

Before performing an ECG, you need to sit quietly in the corridor, relaxing and not thinking about anything, for about 10-15 minutes. Carrying out a cardiogram will not take much time. A person entering the office must undress to the waist and lie down on the couch.

Sometimes the doctor asks you to remove all clothes down to your underwear before the examination, which is due to the diagnosis that is suspected in the patient. Next, the doctor applies a special product in the form of a gel to certain places on the body, which serve as attachment points for wires coming from the cardiograph.

Using special electrodes located on the desired areas, the device detects even the slightest heart impulses, which are reflected on the cardiograph tape in the form of a straight line. The duration of the procedure varies in the range of several minutes.

ECG technique

As planned, ECG recording is carried out in a specialized room equipped with an electrocardiograph. Some modern cardiographs use a thermal printing mechanism instead of a conventional ink recorder, which uses heat to burn the cardiogram curve onto the paper.

But in this case, the cardiogram requires special paper or thermal paper. For clarity and convenience of calculating ECG parameters, cardiographs use graph paper. In the latest modifications of cardiographs, the ECG is displayed on the monitor screen, decrypted using the supplied software, and not only printed on paper, but also saved on digital media (disk, flash drive).

Despite all these improvements, the principle of the ECG recording cardiograph has remained virtually unchanged since Einthoven developed it. Most modern electrocardiographs are multichannel. Unlike traditional single-channel devices, they record not one, but several leads at once.

In 3-channel devices, first standard I, II, III are recorded, then enhanced unipolar leads from the limbs aVL, aVR, aVF, and then the chest leads - V1-3 and V4-6. In 6-channel electrocardiographs, standard and unipolar limb leads are first recorded, and then all chest leads.

The room in which recording is carried out must be removed from sources of electromagnetic fields and X-ray radiation. Therefore, the ECG room should not be placed in close proximity to the X-ray room, rooms where physiotherapeutic procedures are carried out, as well as electric motors, power panels, cables, etc.

There is no special preparation before recording an ECG. It is advisable for the patient to be rested and well-slept. Previous physical and psycho-emotional stress can affect the results and is therefore undesirable. Sometimes food intake can also affect the results. Therefore, an ECG is recorded on an empty stomach, no earlier than 2 hours after a meal.

While recording an ECG, the subject lies on a flat, hard surface (on a couch) in a relaxed state. Places for applying electrodes must be free of clothing. Therefore, you need to undress to the waist, free your shins and feet from clothes and shoes.

Electrodes are applied to the inner surfaces of the lower thirds of the legs and feet (the inner surface of the wrist and ankle joints). These electrodes have the form of plates and are designed for recording standard leads and unipolar leads from the limbs. These same electrodes may look like bracelets or clothespins.

In this case, each limb has its own electrode. To avoid errors and confusion, the electrodes or wires through which they are connected to the device are color coded:

• To the right hand - red;
• To the left hand - yellow;
• To the left leg - green;
• To the right leg - black.

Why do you need a black electrode? After all, the right leg is not included in the Einthoven triangle, and readings are not taken from it. The black electrode is for grounding. According to basic safety requirements, all electrical equipment, incl. and electrocardiographs must be grounded. For this purpose, ECG rooms are equipped with a grounding circuit.

And if the ECG is recorded in a non-specialized room, for example, at home by ambulance workers, the device is grounded to a central heating radiator or to a water pipe. For this there is a special wire with a fixing clip at the end.

Electrodes for recording chest leads have the shape of a suction cup and are equipped with a white wire. If the device is single-channel, there is only one suction cup, and it is moved to the required points on the chest.

In multi-channel devices there are six of these suction cups, and they are also marked with color:

• V1 – red;
• V2 – yellow;
• V3 – green;
• V4 – brown;
• V5 – black;
• V6 – purple or blue.

It is important that all electrodes adhere tightly to the skin. The skin itself should be clean, free of oil, fat and sweat. Otherwise, the quality of the electrocardiogram may deteriorate. Inductive currents, or simply interference, arise between the skin and the electrode.

Quite often, the tip occurs in men with thick hair on the chest and limbs. Therefore, here you need to be especially careful to ensure that the contact between the skin and the electrode is not broken. The interference sharply worsens the quality of the electrocardiogram, which displays small teeth instead of a straight line.

Therefore, it is recommended to degrease the area where the electrodes are applied with alcohol and moisten it with a soap solution or conductive gel. For electrodes from the limbs, gauze wipes soaked in saline solution are also suitable. However, it should be borne in mind that the saline solution dries quickly and the contact may be broken.

Before recording, it is necessary to check the calibration of the device. For this purpose, it has a special button - the so-called. reference millivolt. This value reflects the height of the tooth at a potential difference of 1 millivolt (1 mV). In electrocardiography, the reference millivolt value is 1 cm. This means that with a difference in electrical potentials of 1 mV, the height (or depth) of the ECG wave is 1 cm.

Electrocardiograms are recorded at a tape speed of 10 to 100 mm/s. True, extreme values ​​are used very rarely. Basically, the cardiogram is recorded at a speed of 25 or 50 mm/s. Moreover, the last value, 50 mm/s, is standard and most often used.

A speed of 25 mm/h is used where the greatest number of heart contractions needs to be recorded. After all, the lower the speed of the tape, the greater the number of heart contractions it displays per unit of time. An ECG is recorded during quiet breathing.

In this case, the subject should not talk, sneeze, cough, laugh, or make sudden movements. When registering standard lead III, a deep breath with a short breath hold may be required. This is done in order to distinguish functional changes, which are often found in this lead, from pathological ones.

The section of the cardiogram with teeth corresponding to the systole and diastole of the heart is called the cardiac cycle. Typically, 4-5 cardiac cycles are recorded in each lead. In most cases this is enough. However, in case of cardiac arrhythmias or suspected myocardial infarction, recording up to 8-10 cycles may be required. To switch from one lead to another, the nurse uses a special switch.

At the end of the recording, the subject is released from the electrodes, and the tape is signed - their full name is indicated at the very beginning. and age. Sometimes, to detail the pathology or determine physical endurance, an ECG is performed against the background of medication or physical activity.

Drug tests are carried out with various drugs - atropine, chimes, potassium chloride, beta-blockers. Physical activity is carried out on an exercise bike (bicycle ergometry), walking on a treadmill, or walking for certain distances. To ensure completeness of information, an ECG is recorded before and after exercise, as well as directly during bicycle ergometry.

Many negative changes in heart function, such as rhythm disturbances, are transient and may not be detected during ECG recording even with a large number of leads. In these cases, Holter monitoring is performed - a Holter ECG is recorded in continuous mode throughout the day.

A portable recorder equipped with electrodes is attached to the patient's body. Then the patient goes home, where he follows his usual routine. After 24 hours, the recording device is removed and the available data is decrypted.

A normal ECG looks something like this:

1. All deviations in the cardiogram from the midline (isoline) are called waves.

Teeth deviated upward from the isoline are considered to be positive, and downward - negative. The space between the teeth is called a segment, and the tooth and its corresponding segment are called an interval.

Before finding out what a particular wave, segment or interval represents, it is worth briefly dwelling on the principle of forming an ECG curve.

2. Normally, the cardiac impulse originates in the sinoatrial (sinus) node of the right atrium.

Then it spreads to the atria - first the right, then the left. After this, the impulse is sent to the atrioventricular node (atrioventricular or AV junction), and then along the His bundle.

The branches of the His bundle or pedicles (right, left anterior and left posterior) end in Purkinje fibers. From these fibers, the impulse propagates directly to the myocardium, leading to its contraction - systole, which is replaced by relaxation - diastole.

3. The passage of an impulse along a nerve fiber and the subsequent contraction of the cardiomyocyte is a complex electromechanical process, during which the values ​​of the electrical potentials on both sides of the fiber membrane change. The difference between these potentials is called the transmembrane potential (TMP).

This difference is due to the different permeability of the membrane to potassium and sodium ions. There is more potassium inside the cell, sodium - outside it. As the pulse passes, this permeability changes. In the same way, the ratio of intracellular potassium and sodium and TMP changes.

4. When an excitatory impulse passes, TMP increases inside the cell.

In this case, the isoline shifts upward, forming the ascending part of the tooth. This process is called depolarization. Then, after the passage of the pulse, the TMP tries to take the original value.

However, the permeability of the membrane to sodium and potassium does not immediately return to normal and takes some time.

This process, called repolarization, is manifested on the ECG by a downward deviation of the isoline and the formation of a negative wave. Then the polarization of the membrane takes on the initial resting value (TMP), and the ECG again takes on the character of an isoline. This corresponds to the diastole phase of the heart.

It is noteworthy that the same tooth can look both positive and negative. It all depends on the projection, i.e. the lead in which it is recorded.

ECG waves are usually designated in Latin capital letters, starting with the letter P. The parameters of the waves are direction (positive, negative, biphasic), as well as height and width. Since the height of the tooth corresponds to the change in potential, it is measured in mV.

As already mentioned, a height of 1 cm on the tape corresponds to a potential deviation of 1 mV (reference millivolt). The width of a tooth, segment or interval corresponds to the duration of a phase of a particular cycle. This is a temporary value, and it is customary to denote it not in millimeters, but in milliseconds (ms).

When the tape moves at a speed of 50 mm/s, each millimeter on paper corresponds to 0.02 s, 5 mm - 0.1 ms, and 1 cm - 0.2 ms. It's very simple: if 1 cm or 10 mm (distance) is divided by 50 mm/s (speed), we get 0.2 ms (time).

1. Wave R. Displays the spread of excitation through the atria.

In most leads it is positive, and its height is 0.25 mV and width is 0.1 ms. Moreover, the initial part of the wave corresponds to the passage of the impulse through the right ventricle (since it is excited earlier), and the final part - along the left.

The P wave may be negative or biphasic in leads III, aVL, V1, and V2.

2. P-Q interval (or P-R) is the distance from the beginning of the P wave to the beginning of the next wave - Q or R.

This interval corresponds to the depolarization of the atria and the passage of the impulse through the AV junction, and further along the His bundle and its branches. The size of the interval depends on the heart rate (HR) - the higher it is, the shorter the interval.

Normal values ​​are in the range of 0.12 – 0.2 ms. A wide interval indicates a slowdown in atrioventricular conduction.

3. QRS complex. If P represents the functioning of the atria, then the following waves, Q, R, S and T, reflect the function of the ventricles, and correspond to the various phases of depolarization and repolarization.

The set of QRS waves is called the ventricular QRS complex. Normally, its width should be no more than 0.1 ms. An excess indicates a violation of intraventricular conduction.

4. Wave Q. Corresponds to depolarization of the interventricular septum.

This tooth is always negative. Normally, the width of this wave does not exceed 0.3 ms, and its height is no more than ¼ of the next R wave in the same lead. The only exception is lead aVR, where a deep Q wave is recorded.

In other leads, a deep and widened Q wave (in medical slang - kuishche) may indicate a serious heart pathology - acute myocardial infarction or scars after a heart attack.

Although other reasons are possible - deviations of the electrical axis due to hypertrophy of the heart chambers, positional changes, blockade of the bundle branches.

5. Wave R. Displays the spread of excitation throughout the myocardium of both ventricles.

This wave is positive, and its height does not exceed 20 mm in the limb leads, and 25 mm in the chest leads. The height of the R wave is not the same in different leads.

Normally, it is greatest in lead II. In ore leads V1 and V2 it is low (for this reason it is often denoted by the letter r), then it increases in V3 and V4, and in V5 and V6 it decreases again. In the absence of the R wave, the complex takes on the appearance of QS, which may indicate transmural or cicatricial myocardial infarction.

6. Wave S. Displays the passage of the impulse along the lower (basal) part of the ventricles and the interventricular septum.

This is a negative tooth and its depth varies widely, but should not exceed 25 mm. In some leads the S wave may be absent.

7. Wave T. The final section of the ECG complex, reflecting the phase of rapid ventricular repolarization.

In most leads this wave is positive, but it can also be negative in V1, V2, aVF. The height of the positive waves directly depends on the height of the R wave in the same lead - the higher the R, the higher the T.

The causes of a negative T wave are varied - small-focal myocardial infarction, dyshormonal disorders, previous food intake, changes in the electrolyte composition of the blood, and much more. The width of the T waves usually does not exceed 0.25 ms.

8. S-T segment is the distance from the end of the ventricular QRS complex to the beginning of the T wave, corresponding to full coverage of the ventricles by excitation.

Normally, this segment is located on the isoline or deviates from it slightly - no more than 1-2 mm. Large S-T deviations indicate a severe pathology - a violation of the blood supply (ischemia) of the myocardium, which can lead to a heart attack.

Other, less serious reasons are also possible - early diastolic depolarization, a purely functional and reversible disorder mainly in young men under 40 years of age.

9. Q-T interval is the distance from the beginning of the Q wave to the T wave.

Corresponds to ventricular systole. The size of the interval depends on the heart rate - the faster the heart beats, the shorter the interval.

10. U wave. An unstable positive wave, which is recorded after the T wave after 0.02-0.04 s. The origin of this tooth is not fully understood, and it has no diagnostic value.

From a physical point of view, the work of the heart is an automatic transition from the depolarization phase to the repolarization phase of the heart muscle. In other words, there is a constant change in states of contraction and relaxation of muscle tissue, in which, accordingly, the excitation of myocardial cells is replaced by their restoration.

The design of the ECG device allows you to record electrical impulses that occur in these phases and record them graphically. This is precisely what explains the unevenness of the curve in the cardiogram figure.

To learn how to interpret ECG diagrams, you need to know what elements they consist of, namely:

• tooth – a convex or concave part of a curve relative to the horizontal axis;
• segment - a straight line segment between two adjacent teeth;
• interval – a combination of a tooth and a segment.

Recording of cardiac data is carried out over several cycles, since not only the characteristics of each element of the electrocardiogram are of medical importance, but also their comparability within several cycles.

It is immediately worth noting that with the help of an electrocardiogram you can find out how the heart works. Many people wonder how to decipher a heart cardiogram. The decoding is carried out by the doctor by taking measurements of the duration of the intervals between the components.

This calculation makes it possible to estimate the rhythm frequency, and the teeth show the nature of the heart rhythm. This whole procedure is carried out in a certain order, where violations and norms are determined:

• first of all, heart rate and rhythm indicators are recorded; with a normal electrocardiogram, the rhythm will be sinus, and the heart rate will be from sixty to eighty beats per minute;
• then they begin to calculate the intervals; normally, the QT interval will be 390-450 ms. If there is a prolongation of this interval, then the doctor may suspect coronary heart disease, rheumatism or myocarditis. And if, on the contrary, its shortening is noted, then hypercalcemia can be suspected;
• then the EOS is calculated based on the height of the waves from the midline (in a normal ECG the R wave will be higher than the S wave);
• the QRS complex is studied, normally its width is no more than one hundred and twenty ms;
• Lastly, the ST segments are described, normally it should be in the midline. This segment shows the recovery period after depolarization of the heart muscle.

Thus, deciphering the cardiogram of the heart, the normal photo will look like this: the Q and S waves will always be negative, P and T, R will be positive. The heart rate will vary from sixty to eighty beats per minute, and the rhythm is always sinus. The R wave will be higher than the S wave, and the QRS complex will not be more than one hundred and twenty ms wide.

Decoding a cardiogram is a long process that depends on many indicators. Before deciphering the cardiogram, it is necessary to understand all the deviations in the functioning of the heart muscle. Atrial fibrillation is characterized by irregular contractions of the muscle, which can be completely different.

This violation is dictated by the fact that the clock is set not by the sinus node, as it should happen in a healthy person, but by other cells. The heart rate in this case ranges from 350 to 700. In this condition, the ventricles are not fully filled with incoming blood, which causes oxygen starvation, which affects all organs in the human body.

An analogue of this condition is atrial fibrillation. The pulse in this state will be either below normal (less than 60 beats per minute), or close to normal (60 to 90 beats per minute), or above the specified norm. On the electrocardiogram you can see frequent and constant contractions of the atria and, less often, the ventricles (usually 200 per minute).

This is atrial flutter, which often occurs already in the acute phase. But at the same time, the patient tolerates it more easily than flickering. Blood circulation defects in this case are less pronounced. Trembling can develop as a result of surgery, various diseases such as heart failure or cardiomyopathy.

When a person is examined, fluttering can be detected due to rapid rhythmic heartbeats and pulse, swollen veins in the neck, increased sweating, general impotence and shortness of breath. Conduction disorder - this type of heart disorder is called blockade.

The occurrence is often associated with functional disorders, but it can also be the result of various types of intoxication (due to alcohol or taking medications), as well as various diseases. There are several types of disorders that a heart cardiogram shows. Deciphering these violations is possible based on the results of the procedure.

Sinus arrhythmia can be physiological or pathological. In the physiological form, respiratory arrhythmia is observed, and in the pathological form, a non-respiratory form is observed. The physiological form most often occurs in young people who play sports and suffer from neuroses and neurocirculatory dystonia.

With sinus arrhythmia, it will have the following picture: preserved sinus rhythm, the arrhythmia disappears during breath holding, fluctuations in R-R intervals are observed. Pathological sinus arrhythmia usually appears in elderly people when falling asleep or waking up, as well as in patients with coronary heart disease and cardiomyopathy.

With this form, the cardiogram will show signs of preserved sinus rhythm, which is noted even during breath-holding and abrupt changes in the duration of the R-R intervals.

How does myocardial infarction manifest itself on a cardiogram?

Myocardial infarction is an acute condition of coronary artery disease in which there is insufficient blood supply to some part of the heart muscle. If this area is starved for more than fifteen to twenty minutes, its necrosis occurs, that is, necrosis.

This condition leads to disruption of the entire cardiovascular system and is very dangerous and life-threatening. If there are characteristic symptoms of cardiac dysfunction, the patient is prescribed an electrocardiogram.

Decoding the cardiogram of the heart during a heart attack will have pronounced changes on paper. The following ECG signs indicate a heart attack:

• significant increase in heart rate;
• ST segment elevation is noted;
• The ST segment will have fairly persistent depression in the leads;
• increase in the duration of the QRS complex;
• The cardiogram shows signs of a previous heart attack.

In such a serious disease as myocardial infarction, it is the electrocardiogram that can be the first to recognize dead zones on the heart muscle, determine the location of the lesion and its depth. With the help of this study, the doctor can easily distinguish an acute infarction from an enlargement.

Due to the elevation of the ST segment, deformation of the R wave will be noted, it becomes smoothed. Then a negative T will appear. This total rise in ST on the cardiogram will resemble the arched back of a cat. Sometimes during a heart attack, a Q wave may be observed on the cardiogram.

An electrocardiogram should only be performed by a specialist in a medical facility or by an emergency physician at the patient’s home. Today you can do an ECG at home by calling an ambulance. Almost every ambulance has a special device - an electrocardiograph.

It is small and very convenient, therefore, in case of certain complaints, the patient can undergo this manipulation without visiting a medical institution.

A patient's ECG data can sometimes be different, so if you know how to read a cardiac ECG but see different results in the same patient, don't make a diagnosis prematurely. Accurate results will require taking into account various factors:

• Often distortions are caused by technical defects, for example, inaccurate gluing of the cardiogram.
• Confusion can be caused by Roman numerals, which are the same in the normal and inverted directions.
• Sometimes problems arise as a result of cutting the diagram and losing the first P wave or the last T wave.
• Preliminary preparation for the procedure is also important.
• Electrical appliances operating nearby affect the alternating current in the network, and this is reflected in the repetition of the teeth.
• The instability of the zero line may be affected by the patient’s uncomfortable position or anxiety during the session.
• Sometimes the electrodes become dislodged or incorrectly positioned.

Therefore, the most accurate measurements are obtained using a multichannel electrocardiograph. It is with them that you can test your knowledge of how to decipher an ECG yourself, without fear of making a mistake in making a diagnosis (treatment, of course, can only be prescribed by a doctor).

Not everyone knows how to decipher a heart cardiogram on their own. However, with a good understanding of the indicators, you can independently decipher the ECG and detect changes in the normal functioning of the heart.

First of all, it is worth determining the heart rate indicators. Normally, the heart rhythm should be sinus; the rest indicate the possible development of arrhythmia. Changes in sinus rhythm, or heart rate, suggest the development of tachycardia (faster rhythm) or bradycardia (slower rhythm).

Abnormal data of waves and intervals are also important, since you can read the cardiogram of the heart yourself using their indicators:

1. Prolongation of the QT interval indicates the development of coronary heart disease, rheumatic disease, and sclerotic disorders. A shortening of the interval indicates hypercalcemia.
2. An altered Q wave is a signal of myocardial dysfunction.
3. Sharpening and increased height of the R wave indicates right ventricular hypertrophy.
4. A split and widened P wave indicates left atrial hypertrophy.
5. An increase in the PQ interval and disruption of impulse conduction occurs with atrioventricular block.
6. The degree of deviation from the isoline in the R-ST segment diagnoses myocardial ischemia.
7. Elevation of the ST segment above the isoline is a threat of acute infarction; a decrease in the segment registers ischemia.

There is another method for reading a heart cardiogram yourself. For this you need an electrocardiographic ruler. It helps to decipher an ECG at a speed of 25 mm/s or 50 mm/s. The cardiac ruler consists of divisions (scales) defining:

• heart rate (HR);
• QT interval;
• millivolts;
• isoelectric lines;
• duration of intervals and segments.

This simple and easy-to-use device is useful for everyone to have for independently deciphering the ECG.

Thanks to the ECG, it is possible to diagnose many abnormalities in cardiac activity. The main ones are:

1. Hypertrophy of departments.

This problem occurs due to hemodynamic disturbances. Deviations in the movement of blood through the vessels cause overload of the organ chambers, causing the atria or ventricles to increase in size.

This problem can be identified by the following signs:

• Changes in the electrical axis of the heart.
• Increasing the excitation vector.
• Increase in R wave amplitude.
• Changing the position of the transition zone.

When there are no attacks of the disease, there may be no signs of it on the ECG. This disease exhibits the following features:

• The location of the S-T segment is below the isoline.
• Changes in T wave mapping.

In the presence of this pathology, disturbances in the formation of the impulse occur. Because of this, disruptions in the pulse rhythm occur.
It appears on the ECG as follows:

• There are fluctuations in the P-Q and Q-T display.
• Deviations from the norm in the interval between R-waves.

This is a type of arrhythmia in which the heart rate increases. Its signs on the cardiogram:

• The gap between the R-teeth is less than normal.
• The P-Q section decreases.
• The direction of the teeth remains within normal limits.

This is another type of arrhythmia in which the heart rate decreases. Signs:

• The gap between R and R is increased.
• Growth of the Q-T region is observed.
• The direction of the teeth changes slightly.

In this case, the myocardium increases due to changes in the muscle layers or pathologies in the development of the organ during the prenatal period.

During extrasystole, a focus is formed in the heart that is capable of creating an electrical impulse, which disrupts the rhythm of the sinus node.

This disease is characterized by inflammation of the layers of the pericardial sac.

Other diseases that can be detected using a cardiogram include ischemic heart disease, myocardial infarction, myocarditis, heart failure, etc.

This disease is characterized by inflammation of the layers of the pericardial sac. Other diseases that can be detected using a cardiogram include ischemic heart disease, myocardial infarction, myocarditis, heart failure, etc.

An electrocardiogram is a diagnostic method that allows you to determine the functional state of the most important organ of the human body - the heart. Most people have dealt with such a procedure at least once in their lives. But having received the ECG result, not every person, unless he has a medical education, will be able to understand the terminology used in cardiograms.

What is cardiography

The essence of cardiography is the study of electrical currents arising during the work of the heart muscle. The advantage of this method is its relative simplicity and accessibility. Strictly speaking, a cardiogram is the result of measuring the electrical parameters of the heart, displayed in the form of a time graph.

The creation of electrocardiography in its modern form is associated with the name of the Dutch physiologist of the early 20th century, Willem Einthoven, who developed the basic ECG methods and terminology used by doctors to this day.

Thanks to the cardiogram, it is possible to obtain the following information about the heart muscle:

• Heart rate,
• Physical condition of the heart
• The presence of arrhythmias,
• The presence of acute or chronic myocardial damage,
• The presence of metabolic disorders in the heart muscle,
• Presence of electrical conductivity disturbances,
• Position of the electrical axis of the heart.

Also, a cardiac electrocardiogram can be used to obtain information about certain vascular diseases not related to the heart.

An ECG is usually performed in the following cases:

• Feeling of abnormal heartbeat;
• Attacks of shortness of breath, sudden weakness, fainting;
• Heartache;
• Heart murmurs;
• Deterioration of the condition of patients with cardiovascular diseases;
• Passing medical examinations;
• Medical examination of people over 45 years of age;
• Examination before surgery.

• Pregnancy;
• Endocrine pathologies;
• Nervous diseases;
• Changes in blood counts, especially with an increase in cholesterol;
• Over 40 years of age (once a year).

Where can I get a cardiogram?

If you suspect that there is something wrong with your heart, you can contact a therapist or cardiologist so that he can give you a referral for an ECG. Also, for a fee, a cardiogram can be done in any clinic or hospital.

Methodology of the procedure

ECG recording is usually performed in a supine position. To take a cardiogram, a stationary or portable device is used - an electrocardiograph. Stationary devices are installed in medical institutions, and portable ones are used by emergency teams. The device receives information about electrical potentials on the surface of the skin. For this purpose, electrodes are used that are attached to the chest area and limbs.

These electrodes are called leads. There are usually 6 leads installed on the chest and limbs. The chest leads are designated V1-V6, the leads on the limbs are called basic (I, II, III) and reinforced (aVL, aVR, aVF). All leads give a slightly different picture of oscillations, but by summing up the information from all electrodes, you can find out the details of the functioning of the heart as a whole. Sometimes additional leads are used (D, A, I).

Typically, the cardiogram is displayed in the form of a graph on paper containing millimeter markings. Each electrode lead has its own schedule. The standard speed of the belt is 5 cm/s; other speeds may be used. The cardiogram displayed on the tape can also indicate the main parameters, normal indicators and a conclusion generated automatically. Data can also be recorded in memory and on electronic media.

After the procedure, the cardiogram is usually deciphered by an experienced cardiologist.

Holter monitoring

In addition to stationary devices, there are also portable devices for daily (Holter) monitoring. They are attached to the patient's body along with electrodes and record all information received over a long period of time (usually within 24 hours). This method provides much more complete information about processes in the heart compared to a conventional cardiogram. For example, when taking a cardiogram in a hospital setting, the patient must be at rest. Meanwhile, some deviations from the norm may appear during physical activity, sleep, etc. Holter monitoring provides information about such phenomena.

Other types of procedures

There are several other methods for carrying out the procedure. For example, this is monitoring with physical activity. Abnormalities are usually more pronounced on the stress ECG. The most common way to provide the body with the necessary physical activity is a treadmill. This method is useful in cases where pathologies can only manifest themselves in the case of increased heart function, for example, if coronary artery disease is suspected.

During phonocardiography, not only the electrical potentials of the heart are recorded, but also the sounds that arise in the heart. The procedure is prescribed when it is necessary to clarify the occurrence of a heart murmur. This method is often used when heart defects are suspected.

It is necessary that the patient remains calm during the procedure. A certain period of time must pass between physical activity and the procedure. It is also not recommended to undergo the procedure after eating, drinking alcohol, caffeinated drinks, or cigarettes.

Reasons that can affect the ECG:

• Times of Day,
• Electromagnetic background,
• Physical exercise,
• Eating,
• Electrode position.

Types of teeth

First we should talk a little about how the heart works. It has 4 chambers - two atria and two ventricles (left and right). The electrical impulse, due to which it contracts, is formed, as a rule, in the upper part of the myocardium - in the sinus pacemaker - the sinoatrial (sinus) node. The impulse spreads down the heart, first affecting the atria and causing them to contract, then passes through the atrioventricular nerve node and another nerve node, the bundle of His, and reaches the ventricles. The main burden of pumping blood is taken on by the ventricles, especially the left one, which is involved in the systemic circulation. This stage is called heart contraction or systole.

After contraction of all parts of the heart, the time comes for their relaxation - diastole. The cycle then repeats again and again - this process is called heartbeat.

The condition of the heart, in which there are no changes in the propagation of impulses, is reflected on the ECG in the form of a straight horizontal line, called an isoline. The deviation of the graph from the isoline is called a spike.

One heartbeat on the ECG contains six waves: P, Q, R, S, T, U. The waves can be directed both up and down. In the first case they are considered positive, in the second - negative. The Q and S waves are always positive, and the R wave is always negative.

The teeth reflect the different phases of heart contraction. P reflects the moment of contraction and relaxation of the atria, R – excitation of the ventricles, T – relaxation of the ventricles. Special designations are also used for segments (spaces between adjacent teeth) and intervals (sections of the graph that include segments and teeth), for example, PQ, QRST.

Correspondence between the stages of heart contraction and some elements of cardiograms:

• P – atrial contraction;
• PQ – horizontal line, the transition of the discharge from the atria through the atrioventricular node to the ventricles. The Q wave may be absent normally;
• QRS – ventricular complex, the element most often used in diagnostics;
• R – ventricular excitation;
• S – myocardial relaxation;
• T – ventricular relaxation;
• ST – horizontal line, myocardial recovery;
• U – may be absent normally. The reasons for the appearance of the prong are not clearly understood, but the prong is valuable for diagnosing certain diseases.

Below are some abnormal ECG findings and their possible explanations. This information, of course, does not negate the fact that it is more advisable to entrust the decoding to a professional cardiologist who better knows all the nuances of deviations from the norm and associated pathologies.

Main deviations from the norm and diagnosis

Table of cardiogram parameters in adults

Normal duration of cardiogram elements in children

The norms indicated in the table may also depend on age.

Rhythm of contractions

Violation of the rhythm of contractions is called. The irregularity of the rhythm during arrhythmia is measured as a percentage. An irregular rhythm is indicated by a deviation in the distance between similar teeth by more than 10%. Sinus arrhythmia, that is, arrhythmia combined with sinus rhythm, may be normal for adolescents and young adults, but in most cases it indicates the onset of a pathological process.

A type of arrhythmia is extrasystole. They say it in the case when extraordinary contractions are observed. Single extrasystoles (no more than 200 per day with Holter monitoring) can also be observed in healthy people. Frequent extrasystoles that appear on the cardiogram in the amount of several pieces may indicate ischemia, myocarditis, or heart defects.

Heart rate

This option is the simplest and most understandable. It determines the number of contractions in one minute. The number of contractions may be higher than normal (tachycardia) or lower than normal (bradycardia). The normal heart rate in adults can range from 60 to 80 beats. However, the norm in this case is a relative concept, so bradycardia and tachycardia may not always be evidence of pathology. Bradycardia can occur during sleep or in trained people, and tachycardia can occur during stress, after exercise or at elevated temperatures.

Heart rate norms for children of different ages

Photo: Africa Studio/Shutterstock.com

Heart Rate Types

There are several types of heart rhythm, depending on where the nerve impulse begins to spread, causing the heart to contract:

• Sinus,
• Atrial,
• Atrioventricular,
• Ventricular.

Normally, the rhythm is always sinus. In this case, sinus rhythm can be combined with both a heart rate above normal and a heart rate below normal. All other types of rhythms are evidence of problems with the heart muscle.

Atrial rhythm

Atrial rhythm also often appears on the cardiogram. Is atrial rhythm normal or is it a type of pathology? In most cases, the atrial rhythm on the ECG is not normal. However, this is a relatively mild degree of heart rhythm disturbance. It occurs when the sinus node is suppressed or disrupted. Possible causes are ischemia, hypertension, sick sinus syndrome, endocrine disorders. However, isolated episodes of atrial contractions can also be observed in healthy people. This type of rhythm can take on both the character of bradycardia and the character of tachycardia.

Atrioventricular rhythm

Rhythm emanating from the atrioventricular node. With atrioventricular rhythm, the pulse rate usually drops to less than 60 beats per minute. Causes: weakness of the sinus node, atrioventricular block, taking certain medications. Atrioventricular rhythm, combined with tachycardia, can occur during heart surgery, rheumatism, and heart attack.

Ventricular rhythm

With ventricular rhythm, contractile impulses propagate from the ventricles. The contraction frequency drops to below 40 beats per minute. The most severe form of rhythm disturbance. Occurs in acute infarction, heart defects, cardiosclerosis, cardiac circulatory failure, and in a preagonal state.

Electrical axis of the heart

Another important parameter is the electrical axis of the heart. It is measured in degrees and reflects the direction of propagation of electrical impulses. Normally, it should be slightly inclined to the vertical and be 30-69º. At an angle of 0-30º the axis is said to be horizontal, and at an angle of 70-90º it is said to be vertical. Deviation of the axis in one direction or another may indicate a disease, for example, hypertension or intracardiac blockades.

What do the conclusions on cardiograms mean?

Let's look at some terms that an ECG transcript may contain. They do not always indicate serious pathologies, but in any case they require a visit to a doctor for advice, and sometimes additional examinations.

Photo: Have a nice day Photo/Shutterstock.com

Atrioventricular block

It is reflected on the graph as an increase in the duration of the P-Q interval. Stage 1 disease is reflected in the form of a simple prolongation of the interval. Grade 2 is accompanied by deviation of QRS parameters (loss of this complex). At grade 3, there is no connection between P and the ventricular complex, which means that the ventricles and atria each work in their own rhythm. The syndrome in stages 1 and 2 is not life-threatening, but requires treatment, as it can progress to the extremely dangerous stage 3, in which there is a high risk of cardiac arrest.

Ectopic rhythm

Any heart rhythm that is not sinus. It may indicate the presence of blockades, coronary heart disease, or be a variant of the norm. It can also appear as a result of an overdose of glycosides, neurocirculatory dystonia, and hypertension.

Sinus bradycardia or tachycardia

Sinus rhythm on the ECG, the frequency of which is below (bradycardia) or above (tachycardia) the normal limits. It can be either a variant of the norm or a symptom of certain pathologies. However, in the latter case, this symptom will most likely not be the only one indicated in the transcript of the cardiogram.

Nonspecific ST-T changes

What it is? This entry suggests that the reasons for the interval change are unclear and further research is required. It may indicate a disturbance in metabolic processes in the body, for example a change in the balance of potassium, magnesium, sodium ions or endocrine disorders.

Disorders associated with conduction within the ventricles

As a rule, they are associated with conduction disturbances within the His nerve bundle. May affect the beam trunk or its legs. May lead to a delay in the contraction of one of the ventricles. Direct therapy for His bundle blockades is not carried out; only the disease that caused them is treated.

Incomplete right bundle branch block (RBBB)

Common ventricular conduction disorder. In most cases, however, it does not lead to the development of pathologies and is not their consequence. If the patient does not have problems with the cardiovascular system, then this symptom does not require treatment.

Complete right bundle branch block (RBBB)

This violation is more serious compared to incomplete blockade. May indicate myocardial damage. Usually occurs in older and older people; it is rarely found in children and adolescents. Possible symptoms are shortness of breath, dizziness, general weakness and fatigue.

Block of the anterior branch of the left bundle branch (ALBBB)

Occurs in patients with hypertension who have had a heart attack. It may also indicate cardiomyopathies, cardiosclerosis, atrial septal defect, and mitral valve insufficiency. Has no characteristic symptoms. It is observed mainly in older people (over 55 years old).

Block of the posterior branch of the left bundle branch (B3VLBP)

As a separate symptom, it is rare; as a rule, it is combined with a blockade of the right bundle branch. May indicate a heart attack, cardiosclerosis, cardiomyopathy, or calcification of the conduction system. A blockade is indicated by a deviation in the electrical axis of the heart to the right.

Metabolic changes

Reflects nutritional disorders of the heart muscle. First of all, this concerns the balance of potassium, magnesium, sodium and. The syndrome is not an independent disease, but indicates other pathologies. Can be observed with ischemia, cardiomyopathy, hypertension, rheumatism, cardiosclerosis.

Low voltage ECG

Electrodes installed on the patient's body detect currents of a certain voltage. If the voltage parameters are below normal, then they speak of low voltage. This indicates insufficient external electrical activity of the heart and may be a consequence of pericarditis or a number of other diseases.

Paroxysmal tachycardia

A rare condition that differs from ordinary (sinus) tachycardia, first of all, in that it involves a very high heart rate - more than 130 beats per second. In addition, paroxysmal tachycardia is based on improper circulation of the electrical impulse in the heart.

Atrial fibrillation

Atrial fibrillation is based on atrial fibrillation or flutter. Arrhythmia caused by atrial fibrillation can occur in the absence of heart pathologies, for example, with diabetes, intoxication, and smoking. Atrial flutter may be characteristic of cardiosclerosis, some types of ischemic disease, and inflammatory processes of the myocardium.

Sinoatrial blockade

Difficulty in the exit of an impulse from the sinus (sinoatrial) node. This syndrome is a type of sick sinus syndrome. It is rare, mainly in older people. Possible causes are rheumatism, cardiosclerosis, calcinosis, severe hypertension. May lead to severe bradycardia, fainting, convulsions, and breathing problems.

Hypertrophic conditions of the myocardium

They indicate an overload of certain parts of the heart. The body senses this situation and reacts to it by thickening the muscle walls of the corresponding section. In some cases, the causes of the condition may be hereditary.

Myocardial hypertrophy

General myocardial hypertrophy is a protective reaction, indicating excessive load on the heart. May lead to arrhythmia or heart failure. Sometimes it is a consequence of a heart attack. A type of disease is hypertrophic cardiomyopathy, a hereditary disease that leads to abnormal alignment of heart fibers and carries the risk of sudden cardiac arrest.

Left ventricular hypertrophy

The most common symptom, which does not always indicate severe heart pathologies. May be characteristic of arterial hypertension, obesity, and some heart defects. Sometimes it is observed in trained people, people engaged in heavy physical labor.

Right ventricular hypertrophy

A rarer, but at the same time much more dangerous symptom than left ventricular hypertrophy. Indicates pulmonary circulatory failure, severe pulmonary diseases, valve defects or severe heart defects (tetralogy of Fallot, ventricular septal defect).

Left atrial hypertrophy

Reflected as a change in the P wave on the cardiogram. With this symptom, the tooth has a double peak. Indicates mitral or aortic stenosis, hypertension, myocarditis, cardiomyopathies. Leads to chest pain, shortness of breath, increased fatigue, arrhythmias, and fainting.

Right atrial hypertrophy

Less common than left atrial hypertrophy. It can have many causes - pulmonary pathologies, chronic bronchitis, arterial embolism, tricuspid valve defects. Sometimes observed during pregnancy. May lead to circulatory problems, swelling, and shortness of breath.

Normocardia

Normocardia or normosystole means normal heart rate. However, the presence of normosystole in itself does not indicate that the ECG is normal and everything is in order with the heart, since it may not exclude other pathologies, such as arrhythmias, conduction disorders, etc.

Nonspecific T wave changes

This symptom is typical for approximately 1% of people. A similar conclusion is made if it cannot be unambiguously associated with any other disease. Thus, for nonspecific T wave changes, additional studies are necessary. The sign may be characteristic of hypertension, ischemia, anemia and some other diseases, and may also occur in healthy people.

Tachysystole

Also often called tachycardia. This is the general name for a number of syndromes in which there is an increased frequency of contractions of various parts of the heart. There are ventricular, atrial, and supraventricular tachysystoles. Such types of arrhythmias as paroxysmal tachycardia, atrial fibrillation and flutter also belong to tachysystoles. In most cases, tachysystoles are a dangerous symptom and require serious treatment.

Heart ST depression

ST segment depression is common in high-frequency tachycardias. It often indicates a lack of oxygen supply to the heart muscle and may be characteristic of coronary atherosclerosis. At the same time, the appearance of depression is also observed in healthy people.

Borderline ECG

This conclusion often frightens some patients who have detected it on their cardiograms and are inclined to think that “borderline” means almost “deathbed.” In fact, such a conclusion is never given by a doctor, but is generated by a program that analyzes the parameters of the cardiogram on an automatic basis. Its meaning is that a number of parameters are outside the normal range, but it is impossible to unambiguously draw a conclusion about the presence of some kind of pathology. Thus, the cardiogram is on the border between normal and pathological. Therefore, when receiving such a conclusion, a doctor’s consultation is required, and perhaps everything is not so scary.

Pathological ECG

What it is? This is a cardiogram on which some serious deviations from the norm were clearly detected. These may be arrhythmias, conduction or nutritional disorders of the heart muscle. Pathological changes require immediate consultation with a cardiologist, who should indicate a treatment strategy.

Ischemic changes on the ECG

Coronary artery disease is caused by impaired circulation in the coronary vessels of the heart and can lead to such serious consequences as myocardial infarction. Therefore, identifying ischemic signs on the ECG is a very important task. Early ischemia can be diagnosed by changes in the T wave (rising or falling). At a later stage, changes in the ST segment are observed, and at an acute stage, changes in the Q wave are observed.

Interpretation of ECG in children

In most cases, deciphering a cardiogram in children is not difficult. But the normal parameters and the nature of the disorders may differ compared to similar indicators in adults. So, children normally have a much faster heartbeat. In addition, the sizes of the teeth, intervals and segments are slightly different.

Decoding an ECG is the job of a knowledgeable doctor. This method of functional diagnostics evaluates:

• heart rate - the state of the generators of electrical impulses and the state of the heart system conducting these impulses
• condition of the heart muscle itself (myocardium), the presence or absence of inflammation, damage, thickening, oxygen starvation, electrolyte imbalance

However, modern patients often have access to their medical documents, in particular, to electrocardiography films on which medical reports are written. With their diversity, these records can reach even the most balanced but ignorant person. After all, the patient often does not know for certain how dangerous to life and health is what is written on the back of the ECG film by the hand of a functional diagnostician, and there are still several days before an appointment with a therapist or cardiologist.

To reduce the intensity of passions, we immediately warn readers that with not a single serious diagnosis (myocardial infarction, acute rhythm disturbances), a functional diagnostician will not let a patient leave the office, but, at a minimum, will send him for a consultation with a fellow specialist right there. About the rest of the “open secrets” in this article. In all unclear cases of pathological changes in the ECG, ECG monitoring, 24-hour monitoring (Holter), ECHO cardioscopy (ultrasound of the heart) and stress tests (treadmill, bicycle ergometry) are prescribed.

Numbers and Latin letters in ECG interpretation

PQ- (0.12-0.2 s) – atrioventricular conduction time. Most often it lengthens against the background of AV blockade. Shortened in CLC and WPW syndromes.

P – (0.1s) height 0.25-2.5 mm describes atrial contractions. May indicate their hypertrophy.

QRS – (0.06-0.1s) -ventricular complex

QT – (no more than 0.45 s) lengthens with oxygen starvation (myocardial ischemia, infarction) and the threat of rhythm disturbances.

RR - the distance between the apices of the ventricular complexes reflects the regularity of heart contractions and makes it possible to calculate heart rate.

The interpretation of the ECG in children is presented in Fig. 3

Heart Rate Description Options

Sinus rhythm

This is the most common inscription found on an ECG. And, if nothing else is added and the frequency (HR) is indicated from 60 to 90 beats per minute (for example, HR 68`) - this is the best option, indicating that the heart works like a clock. This is the rhythm set by the sinus node (the main pacemaker that generates electrical impulses that cause the heart to contract). At the same time, sinus rhythm implies well-being, both in the state of this node and the health of the conduction system of the heart. The absence of other records denies pathological changes in the heart muscle and means that the ECG is normal. In addition to sinus rhythm, there may be atrial, atrioventricular or ventricular, indicating that the rhythm is set by cells in these parts of the heart and is considered pathological.

Sinus arrhythmia

This is a normal variant in young people and children. This is a rhythm in which impulses leave the sinus node, but the intervals between heart contractions are different. This may be due to physiological changes (respiratory arrhythmia, when heart contractions slow down during exhalation). Approximately 30% of sinus arrhythmias require observation by a cardiologist, as they are at risk of developing more serious rhythm disturbances. These are arrhythmias after rheumatic fever. Against the background of myocarditis or after it, against the background of infectious diseases, heart defects and in persons with a family history of arrhythmias.

Sinus bradycardia

These are rhythmic contractions of the heart with a frequency of less than 50 per minute. In healthy people, bradycardia occurs, for example, during sleep. Bradycardia also often occurs in professional athletes. Pathological bradycardia may indicate sick sinus syndrome. In this case, bradycardia is more pronounced (heart rate from 45 to 35 beats per minute on average) and is observed at any time of the day. When bradycardia causes pauses in heart contractions of up to 3 seconds during the day and about 5 seconds at night, leads to disturbances in the supply of oxygen to tissues and is manifested, for example, by fainting, an operation is indicated to install a cardiac pacemaker, which replaces the sinus node, imposing a normal rhythm of contractions on the heart.

Sinus tachycardia

Heart rate more than 90 per minute is divided into physiological and pathological. In healthy people, sinus tachycardia is accompanied by physical and emotional stress, drinking coffee, sometimes strong tea or alcohol (especially energy drinks). It is short-lived and after an episode of tachycardia, the heart rate returns to normal within a short period of time after stopping the load. With pathological tachycardia, heartbeats bother the patient at rest. Its causes include fever, infections, blood loss, dehydration, anemia,. The underlying disease is treated. Sinus tachycardia is stopped only in case of a heart attack or acute coronary syndrome.

Extarsystole

These are rhythm disturbances in which foci outside the sinus rhythm give extraordinary cardiac contractions, after which there is a pause of twice the length, called compensatory. In general, the patient perceives heartbeats as uneven, rapid or slow, and sometimes chaotic. The most worrying thing is the dips in heart rate. May occur in the form of tremors, tingling, feelings of fear and emptiness in the stomach.

Not all extrasystoles are dangerous to health. Most of them do not lead to significant circulatory disorders and do not threaten either life or health. They can be functional (against the background of panic attacks, cardioneurosis, hormonal imbalances), organic (with ischemic heart disease, heart defects, myocardial dystrophy or cardiopathy, myocarditis). Intoxication and heart surgery can also lead to them. Depending on the place of occurrence, extrasystoles are divided into atrial, ventricular and anthrioventricular (arising in the node at the border between the atria and ventricles).

• Single extrasystoles most often rare (less than 5 per hour). They are usually functional and do not interfere with normal blood supply.
• Paired extrasystoles two each accompany a certain number of normal contractions. Such rhythm disturbances often indicate pathology and require further examination (Holter monitoring).
• Allorhythmias are more complex types of extrasystoles. If every second contraction is an extrasystole, this is bigymenia, if every third contraction is trigymenia, every fourth is quadrigymenia.

It is customary to divide ventricular extrasystoles into five classes (according to Lown). They are assessed during daily ECG monitoring, since the readings of a regular ECG in a few minutes may not show anything.

• Class 1 - single rare extrasystoles with a frequency of up to 60 per hour, emanating from one focus (monotopic)
• 2 – frequent monotopic more than 5 per minute
• 3 – frequent polymorphic (of different shapes) polytopic (from different foci)
• 4a – paired, 4b – group (trigymenia), episodes of paroxysmal tachycardia
• 5 – early extrasystoles

The higher the class, the more serious the violations, although today even classes 3 and 4 do not always require drug treatment. In general, if there are less than 200 ventricular extrasystoles per day, they should be classified as functional and not worry about them. For more frequent cases, ECHO CS is indicated, and sometimes cardiac MRI is indicated. It is not the extrasystole that is treated, but the disease that leads to it.

Paroxysmal tachycardia

In general, a paroxysm is an attack. A paroxysmal increase in rhythm can last from several minutes to several days. In this case, the intervals between heart contractions will be the same, and the rhythm will increase over 100 per minute (on average from 120 to 250). There are supraventricular and ventricular forms of tachycardia. This pathology is based on abnormal circulation of electrical impulses in the conduction system of the heart. This pathology can be treated. Home remedies to relieve an attack:

• holding your breath
• increased forced cough
• immersing face in cold water

WPW syndrome

Wolff-Parkinson-White syndrome is a type of paroxysmal supraventricular tachycardia. Named after the authors who described it. The appearance of tachycardia is based on the presence of an additional nerve bundle between the atria and ventricles, through which a faster impulse passes than from the main pacemaker.

As a result, an extraordinary contraction of the heart muscle occurs. The syndrome requires conservative or surgical treatment (in case of ineffectiveness or intolerance of antiarrhythmic tablets, during episodes of atrial fibrillation, and with concomitant heart defects).

CLC – syndrome (Clerk-Levi-Christesco)

is similar in mechanism to WPW and is characterized by earlier excitation of the ventricles than normal due to an additional bundle along which the nerve impulse travels. The congenital syndrome is manifested by attacks of rapid heartbeat.

Atrial fibrillation

It can be in the form of an attack or a permanent form. It manifests itself in the form of atrial flutter or fibrillation.

Atrial fibrillation

Atrial fibrillation

When flickering, the heart contracts completely irregularly (the intervals between contractions of very different durations). This is explained by the fact that the rhythm is not set by the sinus node, but by other cells of the atria.

The resulting frequency is from 350 to 700 beats per minute. There is simply no full contraction of the atria; contracting muscle fibers do not effectively fill the ventricles with blood.

As a result, the heart’s output of blood deteriorates and organs and tissues suffer from oxygen starvation. Another name for atrial fibrillation is atrial fibrillation. Not all atrial contractions reach the ventricles of the heart, so the heart rate (and pulse) will be either below normal (bradysystole with a frequency of less than 60), or normal (normosystole from 60 to 90), or above normal (tachysystole more than 90 beats per minute ).

An attack of atrial fibrillation is difficult to miss.

• It usually starts with a strong beat of the heart.
• It develops as a series of absolutely irregular heartbeats with a high or normal frequency.
• The condition is accompanied by weakness, sweating, dizziness.
• The fear of death is very pronounced.
• There may be shortness of breath, general agitation.
• Sometimes observed.
• The attack ends with normalization of the rhythm and the urge to urinate, during which a large amount of urine is released.

To stop an attack, they use reflex methods, drugs in the form of tablets or injections, or resort to cardioversion (stimulating the heart with an electric defibrillator). If an attack of atrial fibrillation is not eliminated within two days, the risks of thrombotic complications (pulmonary embolism, stroke) increase.

With a constant form of heartbeat flicker (when the rhythm is not restored either against the background of drugs or against the background of electrical stimulation of the heart), they become a more familiar companion to patients and are felt only during tachysystole (rapid, irregular heartbeats). The main task when detecting signs of tachysystole of a permanent form of atrial fibrillation on the ECG is to slow down the rhythm to normosystole without trying to make it rhythmic.

Examples of recordings on ECG films:

• atrial fibrillation, tachysystolic variant, heart rate 160 b'.
• Atrial fibrillation, normosystolic variant, heart rate 64 b'.

Atrial fibrillation can develop in the course of coronary heart disease, against the background of thyrotoxicosis, organic heart defects, diabetes mellitus, sick sinus syndrome, and intoxication (most often with alcohol).

Atrial flutter

These are frequent (more than 200 per minute) regular contractions of the atria and equally regular, but less frequent contractions of the ventricles. In general, flutter is more common in the acute form and is better tolerated than flicker, since circulatory disorders are less pronounced. Fluttering develops when:

• organic heart diseases (cardiomyopathies, heart failure)
• after heart surgery
• against the background of obstructive pulmonary diseases
• in healthy people it almost never occurs

Clinically, flutter is manifested by rapid rhythmic heartbeat and pulse, swelling of the neck veins, shortness of breath, sweating and weakness.

Conduction disorders

Normally, having formed in the sinus node, electrical excitation travels through the conduction system, experiencing a physiological delay of a split second in the atrioventricular node. On its way, the impulse stimulates the atria and ventricles, which pump blood, to contract. If in any part of the conduction system the impulse is delayed longer than the prescribed time, then excitation to the underlying sections will come later, and, therefore, the normal pumping work of the heart muscle will be disrupted. Conduction disturbances are called blockades. They can occur as functional disorders, but more often they are the result of drug or alcohol intoxication and organic heart disease. Depending on the level at which they arise, several types are distinguished.

Sinoatrial blockade

When the exit of an impulse from the sinus node is difficult. In essence, this leads to sick sinus syndrome, slowing of contractions to severe bradycardia, impaired blood supply to the periphery, shortness of breath, weakness, dizziness and loss of consciousness. The second degree of this blockade is called Samoilov-Wenckebach syndrome.

Atrioventricular block (AV block)

This is a delay of excitation in the atrioventricular node longer than the prescribed 0.09 seconds. There are three degrees of this type of blockade. The higher the degree, the less often the ventricles contract, the more severe the circulatory disorders.

• In the first, the delay allows each atrial contraction to maintain an adequate number of ventricular contractions.
• The second degree leaves some of the atrial contractions without ventricular contractions. It is described, depending on the prolongation of the PQ interval and the loss of ventricular complexes, as Mobitz 1, 2 or 3.
• The third degree is also called complete transverse blockade. The atria and ventricles begin to contract without interconnection.

In this case, the ventricles do not stop because they obey the pacemakers from the underlying parts of the heart. If the first degree of blockade may not manifest itself in any way and can be detected only with an ECG, then the second is already characterized by sensations of periodic cardiac arrest, weakness, and fatigue. With complete blockades, brain symptoms are added to the manifestations (dizziness, spots in the eyes). Morgagni-Adams-Stokes attacks may develop (when the ventricles escape from all pacemakers) with loss of consciousness and even convulsions.

Impaired conduction within the ventricles

In the ventricles, the electrical signal propagates to the muscle cells through such elements of the conduction system as the trunk of the His bundle, its legs (left and right) and branches of the legs. Blockades can occur at any of these levels, which is also reflected in the ECG. In this case, instead of being simultaneously covered by excitation, one of the ventricles is delayed, since the signal to it bypasses the blocked area.

In addition to the place of origin, a distinction is made between complete or incomplete blockade, as well as permanent and non-permanent blockade. The causes of intraventricular blocks are similar to other conduction disorders (ischemic heart disease, myocarditis and endocarditis, cardiomyopathies, heart defects, arterial hypertension, fibrosis, heart tumors). Also affected are the use of antiarthmic drugs, an increase in potassium in the blood plasma, acidosis, and oxygen starvation.

• The most common is blockade of the anterosuperior branch of the left bundle branch (ALBBB).
• In second place is right leg block (RBBB). This blockade is usually not accompanied by heart disease.
• Left bundle branch block more typical for myocardial lesions. In this case, complete blockade (PBBB) is worse than incomplete blockade (LBBB). It sometimes has to be distinguished from WPW syndrome.
• Block of the posteroinferior branch of the left bundle branch may occur in persons with a narrow and elongated or deformed chest. Among pathological conditions, it is more typical for overload of the right ventricle (with pulmonary embolism or heart defects).

The clinical picture of blockades at the levels of the His bundle is not expressed. The picture of the underlying cardiac pathology comes first.

• Bailey's syndrome is a two-bundle block (of the right bundle branch and the posterior branch of the left bundle branch).

Myocardial hypertrophy

With chronic overload (pressure, volume), the heart muscle in certain areas begins to thicken, and the chambers of the heart begin to stretch. On the ECG, such changes are usually described as hypertrophy.

• (LVH) – typical for arterial hypertension, cardiomyopathy, and a number of heart defects. But even normally, athletes, obese patients and people engaged in heavy physical labor may experience signs of LVH.
• Right ventricular hypertrophy- an undoubted sign of increased pressure in the pulmonary blood flow system. Chronic cor pulmonale, obstructive pulmonary diseases, cardiac defects (pulmonary stenosis, tetralogy of Fallot, ventricular septal defect) lead to RVH.
• Left atrial hypertrophy (LAH)) – with mitral and aortic stenosis or insufficiency, hypertension, cardiomyopathy, after.
• Right atrial hypertrophy (RAH)– with cor pulmonale, tricuspid valve defects, chest deformities, pulmonary pathologies and pulmonary embolism.
• Indirect signs of ventricular hypertrophy- this is a deviation of the electrical axis of the heart (EOC) to the right or left. The left type of EOS is its deviation to the left, that is, LVH, the right type is RVH.
• Systolic overload- This is also evidence of hypertrophy of the heart. Less commonly, this is evidence of ischemia (in the presence of angina pain).

Changes in myocardial contractility and nutrition

Early ventricular repolarization syndrome

Most often, this is a variant of the norm, especially for athletes and people with congenital high body weight. Sometimes associated with myocardial hypertrophy. Refers to the peculiarities of the passage of electrolytes (potassium) through the membranes of cardiocytes and the characteristics of the proteins from which the membranes are built. It is considered a risk factor for sudden cardiac arrest, but does not provide clinical results and most often remains without consequences.

Moderate or severe diffuse changes in the myocardium

This is evidence of a malnutrition of the myocardium as a result of dystrophy, inflammation () or. Also, reversible diffuse changes accompany disturbances in water and electrolyte balance (with vomiting or diarrhea), taking medications (diuretics), and heavy physical activity.

Nonspecific ST changes

This is a sign of deterioration in myocardial nutrition without severe oxygen starvation, for example, in case of disturbances in the balance of electrolytes or against the background of dyshormonal conditions.

Acute ischemia, ischemic changes, T wave changes, ST depression, low T

This describes reversible changes associated with oxygen starvation of the myocardium (ischemia). This can be either stable angina or unstable, acute coronary syndrome. In addition to the presence of the changes themselves, their location is also described (for example, subendocardial ischemia). A distinctive feature of such changes is their reversibility. In any case, such changes require comparison of this ECG with old films, and if a heart attack is suspected, troponin rapid tests for myocardial damage or coronary angiography. Depending on the type of coronary heart disease, anti-ischemic treatment is selected.

Advanced heart attack

It is usually described:

• by stages: acute (up to 3 days), acute (up to 3 weeks), subacute (up to 3 months), cicatricial (all life after a heart attack)
• by volume: transmural (large focal), subendocardial (small focal)
• by location of heart attacks: there are anterior and anterior septal, basal, lateral, inferior (posterior diaphragmatic), circular apical, posterobasal and right ventricular.

In any case, a heart attack is a reason for immediate hospitalization.

The whole variety of syndromes and specific changes on the ECG, the difference in indicators for adults and children, the abundance of reasons leading to the same type of ECG changes do not allow a non-specialist to interpret even the finished conclusion of a functional diagnostician. It is much wiser, having the ECG result in hand, to visit a cardiologist in a timely manner and receive competent recommendations for further diagnosis or treatment of your problem, significantly reducing the risks of emergency cardiac conditions.

In the diagnosis of diseases of the cardiovascular system, electrocardiographic (ECG) research methods play a leading role, being an integral part of clinical studies of patients with cardiovascular diseases.

Purpose of ECG studies:

• assessment of the most important cardiac functions: automaticity, excitability, conductivity;
• diagnosis of coronary heart disease (CHD), including coronary insufficiency;
• determination of the functional class of angina pectoris;
• selection of the most effective drug therapy;
• monitoring the progress of myocardial infarction;
• detection of cardiac conduction and rhythm disturbances;
• identification of other cardiac pathologies (pericarditis, electrolyte and metabolic disorders of the myocardium, etc.).

Options for ECG studies can be divided into two classes:

• ECG at rest- the electrical activity of the heart muscle of a patient at rest (lying down) is recorded;
• ECG under stress- bicycle ergometer test (VEM), treadmill test, Master's test, abnormal load.

Carrying out ECG studies at rest is described in detail in the ECG section.

VEM, Treadmill test

Both of these tests are similar in essence - measuring the electrical activity of the heart during physical activity on a bicycle ergometer or treadmill.

The patient walks on a treadmill, the speed and incline of which are increased stepwise every 3 minutes (the load during VEM is increased every 2 minutes). The subject must stop taking beta blockers and nitrates the day before the test, the last meal should be no later than 4 hours before the test, the patient should be dressed in comfortable clothes that do not restrict his movement.

The studies are carried out in compliance with all precautions under the supervision of a specialist, in order to avoid the development of arrhythmias, an attack of prolonged angina, excessive rise (fall) in blood pressure, and loss of consciousness of the patient.

The purpose of these tests is to determine the amount of load tolerated and assess the threshold at which signs of the disease begin to appear. Having the results of a treadmill test (TEM) in hand, the attending physician can select the most effective treatment tactics for the patient, adjust drug therapy if necessary, and make a more accurate prognosis of the course of the disease.

Indications for performing a treadmill test (TMT):

• in healthy people:
  • determination of exercise tolerance;
  • professional selection;
  • identification of individuals at risk of developing hypertension, when blood pressure increases sharply during physical activity;
  • identification of initial manifestations of atherosclerotic lesions of the coronary arteries and ischemic heart disease;
  • identification of hidden insufficiency of cardiac blood supply with high cholesterol.
• in persons with heart and vascular diseases:
  • detection and identification of arrhythmias;
  • identification of “hidden” ischemia;
  • determination of individual exercise tolerance in patients with coronary artery disease;
  • determination of the functional class of angina pectoris;
  • selection and evaluation of the effectiveness of treatment measures for people who have suffered an MI;
  • examination of the working capacity of patients with heart and vascular diseases.

Absolute contraindications for performing a treadmill test (TEM):

• acute MI;
• uncontrolled arrhythmias accompanied by hemodynamic disturbances;
• heart defects;
• severe heart failure;
• acute vascular conditions;
• acute myocarditis (pericarditis);
• acute dissecting aortic aneurysm.

Clinical criteria for stopping the treadmill test (TMT):

• increase in heart rate to a certain age value;
• development of a classic attack of angina;
• an increase in blood pressure above the maximum limit (systolic blood pressure above 230 mm Hg; diastolic blood pressure - 120 mm Hg);
• blood pressure drop by 25-30% from the original;
• development of an attack of suffocation or pronounced shortness of breath (more than 30 respiratory movements per minute);
• dizziness, severe headache, severe weakness, pallor, cyanosis, severe sweating;
• inappropriate behavior;
• sudden severe fatigue of the subject.

ECG criteria for stopping the treadmill test (TEM):

• downward displacement of the ST segment of an ischemic nature (horizontal; obliquely descending; trough-shaped by 1 mm or more; obliquely ascending by 2 mm or more, lasting more than 0.08 sec after the junction point (J), with a displacement of the J point by 2 mm or more relative to the isoline (more 0.06 sec at heart rate more than 130 beats/min);
• ST segment elevation by 1 mm or more compared to baseline;
• development of arrhythmias: extrasystoles (more than 1:10 extrasystoles), paroxysmal tachycardia, atrial fibrillation;
• cardiac conduction disturbance - appearance (progression) of AV block, bundle branch block;
• change in the QRS complex: R wave volts increased by more than a third; deepening (widening) of q waves (qR); transition of the Q wave to QS;
• development of WPW syndrome, migration of the pacemaker through the atria.

Rice. Ischemic displacements of the ST segment: a) horizontal; b) oblique; c) trough-shaped.

Rice. Oblique displacements of the ST segment: a) no displacement; b) displacement 2 mm.

Rice. Options for ST segment elevation: a) in a calm state; b) at the peak of physical activity.

Evaluation of the results of the treadmill test (TEM)

At each load level of the treadmill test (TEM), the patient’s heart rate and blood pressure are recorded.

• patient complaints before the start of the study;
• medications that the patient took on the eve of the test;
• data on the load size, duration of work at each stage of the test;
• test results recorded by the doctor:
• reason for stopping the test;
• maximum heart rate achieved by the patient;
• the presence of clinical signs of myocardial ischemia (the presence of changes in the ST segment (their nature); the appearance of arrhythmias and cardiac conduction disorders).

Options for a medical opinion based on the results of exercise tests:

• negative test: the subject has reached “his” age heart rate, while no clinical or electrocardiographic signs of ischemia (myocardial dysfunction) were recorded;
• negative test with features: when the age-appropriate heart rate is reached, an extrasystole of less than 4 per 1 minute is recorded; dizziness, headache, shortness of breath, calf pain; significant increase in blood pressure (250/120 or more); reversion (inversion) of the T wave - these symptoms, as signs of coronary artery disease, are nonspecific, as a rule, associated with the patient’s lack of training and lack of experience in performing heavy physical activity;
• positive test: ECG criteria for the presence of myocardial ischemia are recorded, regardless of the simultaneous development (absence) of angina attacks;
• questionable sample:
  • the patient developed pain in the chest characteristic of angina pectoris, which was not confirmed by ischemic changes on the ECG;
  • The ECG recorded a horizontal decrease in the ST segment by 0.5 mm, a slowly ascending decrease in the ST segment to 1 mm;
  • arrhythmias and cardiac conduction disturbances were recorded;
  • at the height of the action of the provoking factor, a decrease in blood pressure of 20 mm Hg was recorded. Art. and more.
• unreliable sample: the patient failed to achieve the required age level of heart rate.

ATTENTION! Information provided on the site website is for reference only. The site administration is not responsible for possible negative consequences if you take any medications or procedures without a doctor’s prescription!

An electrocardiogram is the first indicator of the condition of the heart. It reflects all the problems of the human cardiovascular system, makes it possible to identify ailments in the early stages in order to undertake the necessary treatment. But in order to make a correct diagnosis, the cardiogram must be correctly interpreted.

What does a cardiogram consist of?

Decoding an ECG requires a clear understanding of what this test actually is. An electrocardiogram schematically displays the electrical activity of the heart muscle on paper or electronic media. It is recorded on special calibrated paper. The length of the horizontal axis of the square (the smallest division) is 1 mm, in time it is equal to 0.04 seconds, respectively, large blocks of 5 mm are equal to 0.2 seconds. The black marks at the top indicate three second intervals. A vertical line consisting of two blocks is equal to one millivolt - this is a unit of measurement of electrical voltage, a thousandth of a volt. To understand what we are talking about, it is worth looking at the photo of the ECG transcript.

The cardiogram displays 12 leads: the first half comes from the limbs, and the second - the chest. They depend on the location of the electrodes on the human body, so it is very important to place them correctly. These leads reflect the activity of different parts of the myocardium. Electrodes on the body are placed accordingly.

The propagation of an impulse through the heart on a cardiogram is displayed by intervals, segments and teeth. The latter are denoted by Latin letters: P, Q, R, S, T, U. The R wave is always negative, it displays indicators of the myocardium, Q and S are positive, they show the propagation of the impulse along the interventricular septum. As for the interpretation of the T and U waves, everything depends on their shape, amplitude and sign. The first reflects myocardial repolarization, and the value of the second for diagnosis does not play a special role. Normal ECG interpretation stipulates that all indicators must be calculated to the hundredth of a second, otherwise they can be misinterpreted.

What indicators are considered optimal?

To effectively interpret an ECG, you need to study the normal indicators. First of all, you should pay attention to your heart rate. Normally it should be sinus. This implies that the P waves should have a constant shape, the distance between the P-P and R-R indicators should be the same, and the number of contractions should be 60-80 per minute.

The electrical axis of the heart is a reflection of the vector of excitation of the ventricles from the impulse; it is calculated according to special medical tables, so deciphering an ECG for beginners may seem very difficult. EOS deviations are determined by the alpha angle. If the axis is in its normal position, the angle is 50-70 degrees. It is worth paying attention: the R wave should be higher than the S wave. The intervals of the waves show how the electrical impulse passes between the compartments of the heart. Each of them has specific norm indicators.

1. The width of the group of Q-R-S teeth under normal conditions is 60-100 ms.
2. The Q-T wave group represents the duration of ventricular contraction. The norm is 390-450 ms.
3. For the Q wave, the optimal length is 0.04 s, and the depth is no more than 3 mm.
4. The S wave should not exceed a height of 20 mm.
5. The norm for the T wave is that in leads I and II it should be directed upward, and in lead aVR it should have a negative value.

Detection of abnormalities and diseases

If you understand the normal indicators, when deciphering the ECG, any pathology can be identified independently. Let's start with heart rate. If the electrical excitation does not start from the sinus node, this is an indicator of arrhythmia. Depending on the compartment of the heart in which depolarization begins, tachycardia (acceleration of the rhythm) or bradycardia (slowdown) is diagnosed. Another important indicator of deviations is abnormal teeth and intervals.

1. Prolongation of the interval between the Q and T waves indicates myocarditis, rheumatism, sclerosis or coronary artery disease. When Q values ​​do not meet the norm, this signals myocardial pathologies.


2. If the R wave is not visible in all leads, this indicates that ventricular hypertrophy is possible.
3. Abnormalities in the ST segment indicate myocardial ischemia.
4. A T wave that does not fit within the normal range may indicate hypokalemia or hyperkalemia.
5. Widening of the P wave, especially twice, indicates atrioventricular block.
6. A sharp rise in the ST segment means that the patient is at risk of acute heart attack or pericarditis, and its descent means myocardial ischemia or that the person is taking cardiac glycosides.

This or that position of the electrical axis of the heart may indicate various diseases. When the EOS is horizontal or tilted to the left, we can talk about hypertension in the patient. If the axis deviates to the right, it is possible that the person has chronic lung diseases. The doctor should be concerned if the electrical axis suddenly changes position within a short time. The peculiarity of EOS is that its indicators may depend on various factors. For example, the vertical position is often found in thin people, and the horizontal position in overweight people.

A cardiogram may indicate a number of diseases. But don’t rush to make diagnoses yourself. It is very difficult for beginners to interpret an ECG, because not all indicators can be calculated independently. It is better to contact a professional who will interpret the cardiogram correctly and be able to make accurate diagnoses.

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Basic Rules

When studying the results of a patient's examination, Doctors pay attention to such components of the ECG as:

• Teeth;
• Intervals;
• Segments.

There are strict normal parameters for each line on the ECG tape, the slightest deviation from which may indicate violations in the work of the heart.

Cardiogram analysis

The entire set of ECG lines is examined and measured mathematically, after which the doctor can determine some parameters of the work of the heart muscle and its conduction system: heart rhythm, heart rate, pacemaker, conductivity, electrical axis of the heart.

Today, all these indicators are studied by high-precision electrocardiographs.

Sinus rhythm of the heart

This is a parameter that reflects the rhythm of heart contractions that occur under the influence of the sinus node (normal). It shows the coherence of the work of all parts of the heart, the sequence of processes of tension and relaxation of the heart muscle.

The rhythm is very easily identified by the tallest R waves: if the distance between them is the same throughout the entire recording or deviates by no more than 10%, then the patient does not suffer from arrhythmia.

Heart rate

The number of beats per minute can be determined not only by counting the pulse, but also by ECG. To do this, you need to know the speed at which the ECG was recorded (usually 25, 50 or 100 mm/s), as well as the distance between the highest teeth (from one vertex to another).

Multiplying the recording duration of one mm by length of segment R-R, you can get the heart rate. Normally, its indicators range from 60 to 80 beats per minute.

Excitation source

The autonomic nervous system of the heart is designed in such a way that the contraction process depends on the accumulation of nerve cells in one of the zones of the heart. Normally, this is the sinus node, impulses from which disperse throughout the nervous system of the heart.

In some cases, the role of pacemaker can be taken over by other nodes (atrial, ventricular, atrioventricular). This can be determined by examining the P wave is inconspicuous, located just above the isoline.

Conductivity

This is a criterion showing the process of impulse transmission. Normally, impulses are transmitted sequentially from one pacemaker to another, without changing the order.

Electric axis

An indicator based on the process of ventricular excitation. Mathematical analysis of Q, R, S waves in leads I and III allows one to calculate a certain resulting vector of their excitation. This is necessary to establish the functioning of the branches of the His bundle.

The resulting angle of inclination of the heart axis is estimated by its value: 50-70° normal, 70-90° deviation to the right, 50-0° deviation to the left.

Teeth, segments and intervals

Waves are sections of the ECG lying above the isoline, their meaning is as follows:

• P– reflects the processes of contraction and relaxation of the atria.
• Q, S– reflect the processes of excitation of the interventricular septum.
• R– the process of excitation of the ventricles.
• T- the process of relaxation of the ventricles.

Intervals are ECG sections lying on the isoline.

• PQ– reflects the time of impulse propagation from the atria to the ventricles.

Segments are sections of an ECG, including an interval and a wave.

• QRST– duration of ventricular contraction.
• ST– time of complete excitation of the ventricles.
• TP– time of electrical diastole of the heart.

Normal for men and women

Interpretation of the ECG of the heart and normal indicators in adults are presented in this table:

Healthy Childhood Outcomes

Interpretation of the results of ECG measurements in children and their norm in this table:

Dangerous diagnoses

What dangerous conditions can be determined by ECG readings during interpretation?

Extrasystole

This phenomenon characterized by abnormal heart rhythm. The person feels a temporary increase in contraction frequency followed by a pause. It is associated with the activation of other pacemakers, which, along with the sinus node, send an additional volley of impulses, which leads to an extraordinary contraction.

Arrhythmia

Characterized by change in sinus rhythm periodicity when pulses arrive at different frequencies. Only 30% of such arrhythmias require treatment, because can provoke more serious diseases.

In other cases, this may be a manifestation of physical activity, changes in hormonal levels, the result of a previous fever and does not threaten health.

Bradycardia

Occurs when the sinus node is weakened, unable to generate impulses with the proper frequency, as a result of which the heart rate slows down, up to 30-45 beats per minute.

Tachycardia

The opposite phenomenon, characterized by an increase in heart rate more than 90 beats per minute. In some cases, temporary tachycardia occurs under the influence of severe physical exertion and emotional stress, as well as during illnesses associated with increased temperature.

Conduction disturbance

In addition to the sinus node, there are other underlying pacemakers of the second and third orders. Normally, they conduct impulses from the first-order pacemaker. But if their functions weaken, a person may feel weakness, dizziness caused by depression of the heart.

It is also possible to lower blood pressure, because... the ventricles will contract less frequently or arrhythmically.

Why there might be differences in performance

In some cases, when re-analyzing the ECG, deviations from previously obtained results are revealed. With what it can be connected?

• Different times of day. Typically, an ECG is recommended to be done in the morning or afternoon, when the body has not yet been exposed to stress factors.
• Loads. It is very important that the patient is calm when recording an ECG. The release of hormones can increase heart rate and distort indicators. In addition, it is also not recommended to engage in heavy physical labor before the examination.
• Eating. Digestive processes affect blood circulation, and alcohol, tobacco and caffeine can affect heart rate and blood pressure.
• Electrodes. Incorrect application or accidental displacement can seriously change the indicators. Therefore, it is important not to move during recording and to degrease the skin in the area where the electrodes are applied (the use of creams and other skin products before the examination is highly undesirable).
• Background. Sometimes extraneous devices can affect the operation of the electrocardiograph.

Additional examination techniques

Holter

Method long-term study of heart function, possible thanks to a portable compact tape recorder that is capable of recording results on magnetic film. The method is especially good when it is necessary to study periodically occurring pathologies, their frequency and time of appearance.

Treadmill

Unlike a conventional ECG, which is recorded at rest, this method is based on the analysis of the results after physical activity. Most often, this is used to assess the risk of possible pathologies not detected on a standard ECG, as well as when prescribing a course of rehabilitation for patients who have suffered a heart attack.

Phonocardiography

Allows analyze heart sounds and murmurs. Their duration, frequency and time of occurrence correlate with the phases of cardiac activity, which makes it possible to assess the functioning of the valves and the risks of developing endo- and rheumatic carditis.

A standard ECG is a graphical representation of the work of all parts of the heart. Many factors can affect its accuracy, so the doctor's recommendations should be followed.

The examination reveals most pathologies of the cardiovascular system, but additional tests may be required for an accurate diagnosis.

Finally, we suggest watching a video course on decoding “An ECG can be done by everyone”:

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What is an ECG, how is the procedure performed?

The principle of obtaining an ECG is very simple. This involves attaching sensors to the patient’s skin that record electrical impulses that accompany the heartbeat. The recording is made on a sheet of paper. A competent doctor will be able to tell a lot about the patient’s health using this diagram.

It depicts cyclic changes in the corresponding electrical impulses. It is important to note that this diagnostic method is not absolutely accurate and comprehensive. It can be viewed rather as a basis for the main conclusions.

What exactly is shown in the ECG?

Suppose you need to take an electrocardiogram. How to do this correctly? Do you need to be a specialist in order to carry out this procedure, or can even a non-specialist carry out the procedure if all the necessary rules are carefully followed? Let's try to answer these questions.

It is interesting that the electrocardiogram is used not only in the treatment of heart patients, but also in a number of other cases:

• This occurs not only during various medical examinations, but also for diagnosing those diseases that are not directly related to the heart, but can create complications in it.
• Also, when using those medications that have a strong effect on the body, the health of the cardiovascular system is often checked in this way in order to prevent possible consequences of taking such medications.
  In such cases, it is customary to check not only before, but also after the therapeutic course is completed.

The procedure itself is not very complicated. Its total duration does not exceed ten minutes. The room temperature should not be too low. At the same time, the room must be ventilated. Compliance with this and similar rules is very important for such a procedure. This is due to the fact that any change in the patient’s physical condition will be reflected in the electrocardiogram.

Here are some other requirements:

1. Before starting the procedure, the patient should be given rest. Its duration should be at least a quarter of an hour.
2. During the reading procedure, the patient must lie on his back.
3. He should have even breathing while working.
4. You also need to consider the timing of your meals. Everything should be done either on an empty stomach or no earlier than two hours have passed after the last meal. This intake should not be abundant.
5. Of course, on the day of the procedure you are not allowed to take any sedatives or tonics. You should also not drink coffee or tea or other similar drinks. If the patient smokes, he must refrain from this habit for at least an hour before the procedure.

Diagnostic technique including
It involves attaching four electrodes to the hands and ankles and installing six suction cups on the patient’s chest.

They do this in the following order. Each electrode has a specific color. Place a damp cloth under them. This is done both to increase conductivity and improve adhesion of the electrode to the skin surface.

When installing suction cups on the chest, the skin is usually disinfected with an alcohol solution. The diagram will show several types of teeth that have different shapes.

To carry out diagnostics, it is enough to record data for no longer than four consecutive cycles.

So, in what cases does it make sense to go to the doctor and get a cardiogram?

There are several main options:

• This should be done if you clearly feel discomfort in the chest.
• If you are experiencing shortness of breath, although it may seem normal, it is wise to see your doctor for an ECG.
• If you are overweight, then you are undoubtedly at risk for heart disease. It is recommended to have an electrocardiogram performed regularly.
• Having chronic and severe stress in your life poses a danger not only to your heart, but also to other systems of the human body. An ECG in such a case is vital.
• There is such a chronic disease as tachycardia. If you suffer from it, then an ECG should be done regularly.
• Hypertension is considered by many as a possible step to a heart attack. If at this stage you regularly carry out diagnostics using an ECG, then your chances of recovery will increase dramatically.
• It is important for your doctor to be sure before performing surgery. That your heart can bear it. An ECG may be done to check.

How often is it necessary to resort to such a procedure? This is usually determined by the attending physician. However, if you are over forty, then it makes sense to carry out this procedure annually. If you are much older, then you should do an ECG at least once a quarter.

What does an ECG show?

Let's see what we can see on the electrocardiogram:

1. First of all, she will tell you in detail about all the features of the heartbeat rhythm. In particular, this will allow you to track the increase in heart rate or weak heartbeat. The diagram shows in what rhythm and with what force the patient’s heart beats.
2. Another important advantage is that an ECG can show various pathologies that are inherent in the heart. This is due to the fact that any, say, tissue necrosis will conduct electrical impulses differently than healthy tissue. Such features will also help identify those who are not yet sick, but have a tendency towards it.
3. There is ECG recording under stress. This is useful in cases where a relatively healthy person wants to assess the health of their heart.

Principles for deciphering indicators

A cardiogram is not one, but several different graphs. Since multiple electrodes are attached to the patient, electrical impulses can in principle be measured between each pair of electrodes. In practice, an ECG contains twelve graphs. The doctor evaluates the shape and periodicity of the teeth, and also examines the relationship of electrical signals on various graphs.

Each disease corresponds to specific signs on ECG graphs. If they are identified, this makes it possible to make a correct diagnosis for the patient. The norm and abnormalities in deciphering the ECG are very important. Each indicator requires the most careful attention. A reliable result occurs when the analysis is carried out accurately and reliably.

Reading the teeth

There are five different types of waves on a cardiogram. They are designated by Latin letters: S, P, T, Q And R. Each of them characterizes the work of one of the parts of the heart.

Various types of intervals and segments are also taken into account. They represent the distance between certain types of teeth and also have their own letter designations.

The analysis also considers the QRS complex (it is also called the QRS interval).

The ECG elements are shown in more detail in the figure given here. This is a kind of ECG decoding table.
First, the heart rate is assessed. As you know, it is usually 60-80 contractions per second.

How a doctor analyzes the results

The study of the electrocardiogram occurs in several successive stages:

1. At this stage, the doctor must calculate and analyze the intervals. The doctor examines the QT interval. If there is a lengthening of this segment, then this indicates, in particular, coronary heart disease; if we are talking about shortening, then we can talk about hypercalcemia.
2. After this, an indicator such as the electrical axis of the heart (EOS) is determined. This is done using a calculation based on the height of different types of waves on the electrocardiogram.
3. After this, the complex is considered. We are talking about the wave of type R and its closest sections of the graph on both sides.
4. Next we consider the interval. It is believed that for a normal heart it should be in the midline.
5. After this, based on the studied data, a final cardiological conclusion is given.

• P – normally should be positive, indicating the presence of bioelectricity in the atria;
• The Q wave is normally negative and refers to the interventricular septum;
• R – characterizes the electrical potential in the ventricular myocardium;
• The S wave – in a normal situation it is negative, shows the final process of the work of electricity in the ventricles; normally, such a wave will be lower than the R wave;
• T – must be positive, here we are talking about the restoration process of biopotential in the heart.
• The heart rate should be between 60 and 80 per minute. If it goes beyond these boundaries, then this indicates disturbances in the functioning of the heart.
• The normal QT interval for an adult is 390-450 milliseconds.
• The width of the QRS interval should be approximately 120 milliseconds.

Possible errors as a result

Despite its obvious advantages, this procedure also has certain disadvantages:

Pathologies in ECG interpretation can be determined according to the available descriptions of various variants of cardiograms. There are detailed tables that will help determine the type of pathology detected. To increase the reliability of the result, the cardiogram should be combined with other diagnostic methods.

Cost of the procedure

If we talk about prices in Moscow, they are approximately in the range from 650 to 2300 rubles. Let’s not forget that when receiving a cardiogram, its analysis by a qualified doctor and the quality of the medical equipment itself are of great importance.

In St. Petersburg, the average price is approximately the same as in Moscow. ECG price with interpretation is approximately 1500 rubles for this procedure.

There is also a service for calling such a specialist to your home. In Moscow this service can be provided for 1,500 rubles, in Khabarovsk for 900 rubles, and in Saratov it can be done for 750 rubles.

Conclusion

An ECG is an important diagnostic tool for your cardiovascular system. She has a lot to say about her. It makes sense to regularly, at least once every two years, consult a doctor for an ECG.

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ECG interpretation

Any electrocardiogram displays the work of the heart (its electrical potential during contractions and relaxations) in 12 curves recorded in 12 leads. These curves differ from each other because they show the passage of an electrical impulse through different parts of the heart, for example, the first is the anterior surface of the heart, the third is the posterior. To record a 12-lead ECG, special electrodes are attached to the patient’s body in specific places and in a certain sequence.

How to decipher a heart cardiogram: general principles

The main elements of the electrocardiographic curve are:

ECG analysis

Having received an electrocardiogram in his hands, the doctor begins to evaluate it in the following sequence:

1. Determines whether the heart contracts rhythmically, that is, whether the rhythm is correct. To do this, measures the intervals between the R waves; they must be the same everywhere; if not, this is already an incorrect rhythm.
2. Calculates the rate at which the heart contracts (HR). This is easy to do if you know the ECG recording speed and count the number of millimeter cells between adjacent R waves. Normally, heart rate should not go beyond 60-90 beats. in a minute.
3. Based on specific signs (mainly the P wave), it determines the source of excitation in the heart. Normally, this is the sinus node, that is, in a healthy person, sinus rhythm is considered normal. Atrial, atrioventricular and ventricular rhythms indicate pathology.
4. Evaluates cardiac conductivity by the duration of waves and segments. Each of them has its own norm indicators.
5. Determines the electrical axis of the heart (EOS). Very thin people are characterized by a more vertical position of the EOS, while overweight people tend to have a more horizontal position. With pathology, the axis shifts sharply to the right or left.
6. Analyzes teeth, segments and intervals in detail. The doctor writes down their duration on the cardiogram by hand in seconds (this is an incomprehensible set of Latin letters and numbers on the ECG). Modern electrocardiographs automatically analyze these indicators and immediately provide measurement results, which simplifies the doctor’s work.
7. Gives a conclusion. It necessarily indicates the correctness of the rhythm, the source of excitation, heart rate, characterizes the EOS, and also identifies specific pathological syndromes (rhythm disturbances, conduction disturbances, the presence of overload of certain parts of the heart and myocardial damage), if any.

Examples of electrocardiographic reports

In a healthy person, the ECG conclusion may look like this: sinus rhythm with a heart rate of 70 beats. per minute The EOS is in a normal position, no pathological changes were detected.

Also, for some people, sinus tachycardia (heart rate acceleration) or bradycardia (heart rate slowdown) may be considered a normal variant. In elderly people, quite often the conclusion may indicate the presence of moderate diffuse or metabolic changes in the myocardium. These conditions are not critical and, after receiving appropriate treatment and correcting the patient’s diet, mostly always disappear.

In addition, the conclusion may indicate a nonspecific change in the ST-T interval. This means that the changes are not indicative and their cause cannot be determined by ECG alone. Another fairly common condition that can be diagnosed using a cardiogram is a violation of repolarization processes, that is, a violation of the recovery of the ventricular myocardium after excitation. This change can be caused by both severe heart disease and chronic infections, hormonal imbalance and other reasons that the doctor will subsequently look for.

Conclusions that contain data on the presence of myocardial ischemia, hypertrophy of the heart, rhythm and conduction disturbances are considered prognostically unfavorable.

Interpretation of ECG in children

The whole principle of deciphering cardiograms is the same as in adults, but due to the physiological and anatomical characteristics of the children's heart, there are differences in the interpretation of normal indicators. This primarily concerns heart rate, since in children under 5 years of age it can exceed 100 beats. in a minute.

Also, children may experience sinus or respiratory arrhythmia (increased heart rate during inhalation and decreased during exhalation) without any pathology. In addition, the characteristics of some waves and intervals differ from those of adults. For example, a child may have an incomplete blockade of part of the conduction system of the heart - the right bundle branch. Pediatric cardiologists take all these features into account when making a conclusion based on the ECG.

Features of ECG during pregnancy

The body of a pregnant woman goes through various processes of adaptation to the new position. Certain changes also occur in the cardiovascular system, so the ECG of expectant mothers may differ slightly from the results of a study of the heart of a healthy adult. First of all, in the later stages there is a slight horizontal deviation of the EOS, caused by a change in the relative placement of the internal organs and the growing uterus.

In addition, expectant mothers may experience slight sinus tachycardia and signs of overload in certain parts of the heart. These changes are associated with an increase in blood volume in the body and, as a rule, disappear after childbirth. However, their detection cannot be left without a detailed examination and a more in-depth examination of the woman.

ECG interpretation, normal indicators

Decoding an ECG is the job of a knowledgeable doctor. This method of functional diagnostics evaluates:

• heart rate - the state of the generators of electrical impulses and the state of the heart system conducting these impulses
• the condition of the heart muscle itself (myocardium). the presence or absence of inflammation, damage, thickening, oxygen starvation, electrolyte imbalance

However, modern patients often have access to their medical documents, in particular, to electrocardiography films on which medical reports are written. With their diversity, these recordings can drive even the most balanced but ignorant person to panic disorder. After all, the patient often does not know for certain how dangerous to life and health is what is written on the back of the ECG film by the hand of a functional diagnostician, and there are still several days before an appointment with a therapist or cardiologist.

To reduce the intensity of passions, we immediately warn readers that with not a single serious diagnosis (myocardial infarction, acute rhythm disturbances), a functional diagnostician will not let a patient leave the office, but, at a minimum, will send him for a consultation with a fellow specialist right there. About the rest of the “open secrets” in this article. In all unclear cases of pathological changes in the ECG, ECG monitoring, 24-hour monitoring (Holter), ECHO cardioscopy (ultrasound of the heart) and stress tests (treadmill, bicycle ergometry) are prescribed.

Numbers and Latin letters in ECG interpretation

PQ- (0.12-0.2 s) – atrioventricular conduction time. Most often it lengthens against the background of AV blockade. Shortened in CLC and WPW syndromes.

P – (0.1s) height 0.25-2.5 mm describes atrial contractions. May indicate their hypertrophy.

QRS – (0.06-0.1s) -ventricular complex

QT – (no more than 0.45 s) lengthens with oxygen starvation (myocardial ischemia, infarction) and the threat of rhythm disturbances.

RR - the distance between the apices of the ventricular complexes reflects the regularity of heart contractions and makes it possible to calculate heart rate.

The interpretation of the ECG in children is presented in Fig. 3

Heart Rate Description Options

Sinus rhythm

This is the most common inscription found on an ECG. And, if nothing else is added and the frequency (HR) is indicated from 60 to 90 beats per minute (for example, HR 68`) - this is the best option, indicating that the heart works like a clock. This is the rhythm set by the sinus node (the main pacemaker that generates electrical impulses that cause the heart to contract). At the same time, sinus rhythm implies well-being, both in the state of this node and the health of the conduction system of the heart. The absence of other records denies pathological changes in the heart muscle and means that the ECG is normal. In addition to sinus rhythm, there may be atrial, atrioventricular or ventricular, indicating that the rhythm is set by cells in these parts of the heart and is considered pathological.

This is a normal variant in young people and children. This is a rhythm in which impulses leave the sinus node, but the intervals between heart contractions are different. This may be due to physiological changes (respiratory arrhythmia, when heart contractions slow down during exhalation). Approximately 30% of sinus arrhythmias require observation by a cardiologist, as they are at risk of developing more serious rhythm disturbances. These are arrhythmias after rheumatic fever. Against the background of myocarditis or after it, against the background of infectious diseases, heart defects and in persons with a family history of arrhythmias.

These are rhythmic contractions of the heart with a frequency of less than 50 per minute. In healthy people, bradycardia occurs, for example, during sleep. Bradycardia also often occurs in professional athletes. Pathological bradycardia may indicate sick sinus syndrome. In this case, bradycardia is more pronounced (heart rate from 45 to 35 beats per minute on average) and is observed at any time of the day. When bradycardia causes pauses in heart contractions of up to 3 seconds during the day and about 5 seconds at night, leads to disturbances in the supply of oxygen to tissues and is manifested, for example, by fainting, an operation is indicated to install a cardiac pacemaker, which replaces the sinus node, imposing a normal rhythm of contractions on the heart.

Sinus tachycardia

Heart rate more than 90 per minute is divided into physiological and pathological. In healthy people, sinus tachycardia is accompanied by physical and emotional stress, drinking coffee, sometimes strong tea or alcohol (especially energy drinks). It is short-lived and after an episode of tachycardia, the heart rate returns to normal within a short period of time after stopping the load. With pathological tachycardia, heartbeats bother the patient at rest. Its causes are fever, infections, blood loss, dehydration, thyrotoxicosis, anemia, cardiomyopathy. The underlying disease is treated. Sinus tachycardia is stopped only in case of a heart attack or acute coronary syndrome.

Extarsystole

These are rhythm disturbances in which foci outside the sinus rhythm give extraordinary cardiac contractions, after which there is a pause of twice the length, called compensatory. In general, the patient perceives heartbeats as uneven, rapid or slow, and sometimes chaotic. The most worrying thing is the dips in heart rate. There may be unpleasant sensations in the chest in the form of tremors, tingling, feelings of fear and emptiness in the stomach.

Not all extrasystoles are dangerous to health. Most of them do not lead to significant circulatory disorders and do not threaten either life or health. They can be functional (against the background of panic attacks, cardioneurosis, hormonal imbalances), organic (with ischemic heart disease, heart defects, myocardial dystrophy or cardiopathy, myocarditis). Intoxication and heart surgery can also lead to them. Depending on the place of occurrence, extrasystoles are divided into atrial, ventricular and anthrioventricular (arising in the node at the border between the atria and ventricles).

• Single extrasystoles are most often rare (less than 5 per hour). They are usually functional and do not interfere with normal blood supply.
• Paired extrasystoles, two at a time, accompany a certain number of normal contractions. Such rhythm disturbances often indicate pathology and require further examination (Holter monitoring).
• Allorhythmias are more complex types of extrasystoles. If every second contraction is an extrasystole, this is bigymenia, if every third contraction is trigymenia, every fourth is quadrigymenia.

It is customary to divide ventricular extrasystoles into five classes (according to Lown). They are assessed during daily ECG monitoring, since the readings of a regular ECG in a few minutes may not show anything.

• Class 1 - single rare extrasystoles with a frequency of up to 60 per hour, emanating from one focus (monotopic)
• 2 – frequent monotopic more than 5 per minute
• 3 – frequent polymorphic (of different shapes) polytopic (from different foci)
• 4a – paired, 4b – group (trigymenia), episodes of paroxysmal tachycardia
• 5 – early extrasystoles

The higher the class, the more serious the violations, although today even classes 3 and 4 do not always require drug treatment. In general, if there are less than 200 ventricular extrasystoles per day, they should be classified as functional and not worry about them. For more frequent cases, ECHO CS is indicated, and sometimes cardiac MRI is indicated. It is not the extrasystole that is treated, but the disease that leads to it.

Paroxysmal tachycardia

In general, a paroxysm is an attack. A paroxysmal increase in rhythm can last from several minutes to several days. In this case, the intervals between heart contractions will be the same, and the rhythm will increase over 100 per minute (on average from 120 to 250). There are supraventricular and ventricular forms of tachycardia. This pathology is based on abnormal circulation of electrical impulses in the conduction system of the heart. This pathology can be treated. Home remedies to relieve an attack:

• holding your breath
• increased forced cough
• immersing face in cold water

WPW syndrome

Wolff-Parkinson-White syndrome is a type of paroxysmal supraventricular tachycardia. Named after the authors who described it. The appearance of tachycardia is based on the presence of an additional nerve bundle between the atria and ventricles, through which a faster impulse passes than from the main pacemaker.

As a result, an extraordinary contraction of the heart muscle occurs. The syndrome requires conservative or surgical treatment (in case of ineffectiveness or intolerance of antiarrhythmic tablets, during episodes of atrial fibrillation, and with concomitant heart defects).

CLC – syndrome (Clerk-Levi-Christesco)

is similar in mechanism to WPW and is characterized by earlier excitation of the ventricles than normal due to an additional bundle along which the nerve impulse travels. The congenital syndrome is manifested by attacks of rapid heartbeat.

Atrial fibrillation

It can be in the form of an attack or a permanent form. It manifests itself in the form of atrial flutter or fibrillation.

Atrial fibrillation

Atrial fibrillation

When flickering, the heart contracts completely irregularly (the intervals between contractions of very different durations). This is explained by the fact that the rhythm is not set by the sinus node, but by other cells of the atria.

The resulting frequency is from 350 to 700 beats per minute. There is simply no full contraction of the atria; contracting muscle fibers do not effectively fill the ventricles with blood.

As a result, the heart’s output of blood deteriorates and organs and tissues suffer from oxygen starvation. Another name for atrial fibrillation is atrial fibrillation. Not all atrial contractions reach the ventricles of the heart, so the heart rate (and pulse) will be either below normal (bradysystole with a frequency of less than 60), or normal (normosystole from 60 to 90), or above normal (tachysystole more than 90 beats per minute ).

An attack of atrial fibrillation is difficult to miss.

• It usually starts with a strong beat of the heart.
• It develops as a series of absolutely irregular heartbeats with a high or normal frequency.
• The condition is accompanied by weakness, sweating, dizziness.
• The fear of death is very pronounced.
• There may be shortness of breath, general agitation.
• Sometimes there is loss of consciousness.
• The attack ends with normalization of the rhythm and the urge to urinate, during which a large amount of urine is released.

To stop an attack, they use reflex methods, drugs in the form of tablets or injections, or resort to cardioversion (stimulating the heart with an electric defibrillator). If an attack of atrial fibrillation is not eliminated within two days, the risks of thrombotic complications (pulmonary embolism, stroke) increase.

With a constant form of heartbeat flicker (when the rhythm is not restored either against the background of drugs or against the background of electrical stimulation of the heart), they become a more familiar companion to patients and are felt only during tachysystole (rapid, irregular heartbeats). The main task when detecting signs of tachysystole of a permanent form of atrial fibrillation on the ECG is to slow down the rhythm to normosystole without trying to make it rhythmic.

Examples of recordings on ECG films:

• atrial fibrillation, tachysystolic variant, heart rate 160 b'.
• Atrial fibrillation, normosystolic variant, heart rate 64 b'.

Atrial fibrillation can develop in the course of coronary heart disease, against the background of thyrotoxicosis, organic heart defects, diabetes mellitus, sick sinus syndrome, and intoxication (most often with alcohol).

Atrial flutter

These are frequent (more than 200 per minute) regular contractions of the atria and equally regular, but less frequent contractions of the ventricles. In general, flutter is more common in the acute form and is better tolerated than flicker, since circulatory disorders are less pronounced. Fluttering develops when:

• organic heart diseases (cardiomyopathies, heart failure)
• after heart surgery
• against the background of obstructive pulmonary diseases
• in healthy people it almost never occurs

Clinically, flutter is manifested by rapid rhythmic heartbeat and pulse, swelling of the neck veins, shortness of breath, sweating and weakness.

Conduction disorders

Normally, having formed in the sinus node, electrical excitation travels through the conduction system, experiencing a physiological delay of a split second in the atrioventricular node. On its way, the impulse stimulates the atria and ventricles, which pump blood, to contract. If in any part of the conduction system the impulse is delayed longer than the prescribed time, then excitation to the underlying sections will come later, and, therefore, the normal pumping work of the heart muscle will be disrupted. Conduction disturbances are called blockades. They can occur as functional disorders, but more often they are the result of drug or alcohol intoxication and organic heart disease. Depending on the level at which they arise, several types are distinguished.

Sinoatrial blockade

When the exit of an impulse from the sinus node is difficult. In essence, this leads to sick sinus syndrome, slowing of contractions to severe bradycardia, impaired blood supply to the periphery, shortness of breath, weakness, dizziness and loss of consciousness. The second degree of this blockade is called Samoilov-Wenckebach syndrome.

Atrioventricular block (AV block)

This is a delay of excitation in the atrioventricular node longer than the prescribed 0.09 seconds. There are three degrees of this type of blockade. The higher the degree, the less often the ventricles contract, the more severe the circulatory disorders.

• In the first, the delay allows each atrial contraction to maintain an adequate number of ventricular contractions.
• The second degree leaves some of the atrial contractions without ventricular contractions. It is described, depending on the prolongation of the PQ interval and the loss of ventricular complexes, as Mobitz 1, 2 or 3.
• The third degree is also called complete transverse blockade. The atria and ventricles begin to contract without interconnection.

In this case, the ventricles do not stop because they obey the pacemakers from the underlying parts of the heart. If the first degree of blockade may not manifest itself in any way and can be detected only with an ECG, then the second is already characterized by sensations of periodic cardiac arrest, weakness, and fatigue. With complete blockades, brain symptoms are added to the manifestations (dizziness, spots in the eyes). Morgagni-Adams-Stokes attacks may develop (when the ventricles escape from all pacemakers) with loss of consciousness and even convulsions.

Impaired conduction within the ventricles

In the ventricles, the electrical signal propagates to the muscle cells through such elements of the conduction system as the trunk of the His bundle, its legs (left and right) and branches of the legs. Blockades can occur at any of these levels, which is also reflected in the ECG. In this case, instead of being simultaneously covered by excitation, one of the ventricles is delayed, since the signal to it bypasses the blocked area.

In addition to the place of origin, a distinction is made between complete or incomplete blockade, as well as permanent and non-permanent blockade. The causes of intraventricular blocks are similar to other conduction disorders (ischemic heart disease, myocarditis and endocarditis, cardiomyopathies, heart defects, arterial hypertension, fibrosis, heart tumors). Also affected are the use of antiarthmic drugs, an increase in potassium in the blood plasma, acidosis, and oxygen starvation.

• The most common is blockade of the anterosuperior branch of the left bundle branch (ALBBB).
• In second place is right leg block (RBBB). This blockade is usually not accompanied by heart disease.
• Left bundle branch block is more typical for myocardial lesions. In this case, complete blockade (PBBB) is worse than incomplete blockade (LBBB). It sometimes has to be distinguished from WPW syndrome.
• Blockade of the posteroinferior branch of the left bundle branch can occur in individuals with a narrow and elongated or deformed chest. Among pathological conditions, it is more typical for overload of the right ventricle (with pulmonary embolism or heart defects).

The clinical picture of blockades at the levels of the His bundle is not expressed. The picture of the underlying cardiac pathology comes first.

• Bailey's syndrome is a two-bundle block (of the right bundle branch and the posterior branch of the left bundle branch).

Myocardial hypertrophy

With chronic overload (pressure, volume), the heart muscle in certain areas begins to thicken, and the chambers of the heart begin to stretch. On the ECG, such changes are usually described as hypertrophy.

• Left ventricular hypertrophy (LVH) is typical for arterial hypertension, cardiomyopathy, and a number of heart defects. But even normally, athletes, obese patients and people engaged in heavy physical labor may experience signs of LVH.
• Right ventricular hypertrophy is an undoubted sign of increased pressure in the pulmonary blood flow system. Chronic cor pulmonale, obstructive pulmonary diseases, cardiac defects (pulmonary stenosis, tetralogy of Fallot, ventricular septal defect) lead to RVH.
• Left atrial hypertrophy (LAH) – with mitral and aortic stenosis or insufficiency, hypertension, cardiomyopathy, after myocarditis.
• Right atrial hypertrophy (RAH) – with cor pulmonale, tricuspid valve defects, chest deformities, pulmonary pathologies and PE.
• Indirect signs of ventricular hypertrophy are deviation of the electrical axis of the heart (EOC) to the right or left. The left type of EOS is its deviation to the left, that is, LVH, the right type is RVH.
• Systolic overload is also evidence of hypertrophy of the heart. Less commonly, this is evidence of ischemia (in the presence of angina pain).

Changes in myocardial contractility and nutrition

Early ventricular repolarization syndrome

Most often, this is a variant of the norm, especially for athletes and people with congenital high body weight. Sometimes associated with myocardial hypertrophy. Refers to the peculiarities of the passage of electrolytes (potassium) through the membranes of cardiocytes and the characteristics of the proteins from which the membranes are built. It is considered a risk factor for sudden cardiac arrest, but does not provide clinical results and most often remains without consequences.

Moderate or severe diffuse changes in the myocardium

This is evidence of a malnutrition of the myocardium as a result of dystrophy, inflammation (myocarditis) or cardiosclerosis. Also, reversible diffuse changes accompany disturbances in water and electrolyte balance (with vomiting or diarrhea), taking medications (diuretics), and heavy physical activity.

This is a sign of deterioration in myocardial nutrition without severe oxygen starvation, for example, in case of disturbances in the balance of electrolytes or against the background of dyshormonal conditions.

Acute ischemia, ischemic changes, T wave changes, ST depression, low T

This describes reversible changes associated with oxygen starvation of the myocardium (ischemia). This can be either stable angina or unstable, acute coronary syndrome. In addition to the presence of the changes themselves, their location is also described (for example, subendocardial ischemia). A distinctive feature of such changes is their reversibility. In any case, such changes require comparison of this ECG with old films, and if a heart attack is suspected, troponin rapid tests for myocardial damage or coronary angiography. Depending on the type of coronary heart disease, anti-ischemic treatment is selected.

Advanced heart attack

It is usually described:

• by stages. acute (up to 3 days), acute (up to 3 weeks), subacute (up to 3 months), cicatricial (all life after a heart attack)
• by volume. transmural (large focal), subendocardial (small focal)
• according to the location of heart attacks. There are anterior and anterior septal, basal, lateral, inferior (posterior diaphragmatic), circular apical, posterobasal and right ventricular.

The whole variety of syndromes and specific changes on the ECG, the difference in indicators for adults and children, the abundance of reasons leading to the same type of ECG changes do not allow a non-specialist to interpret even the finished conclusion of a functional diagnostician. It is much wiser, having the ECG result in hand, to visit a cardiologist in a timely manner and receive competent recommendations for further diagnosis or treatment of your problem, significantly reducing the risks of emergency cardiac conditions.

How to decipher ECG indicators of the heart?

An electrocardiographic study is the simplest, but very informative method of studying the functioning of a patient’s heart. The result of this procedure is an ECG. Incomprehensible lines on a piece of paper contain a lot of information about the state and functioning of the main organ in the human body. Decoding ECG indicators is quite simple. The main thing is to know some of the secrets and features of this procedure, as well as the norms of all indicators.

Exactly 12 curves are recorded on the ECG. Each of them talks about the work of each specific part of the heart. So, the first curve is the anterior surface of the heart muscle, and the third line is its posterior surface. To record a cardiogram of all 12 leads, electrodes are attached to the patient’s body. The specialist does this sequentially, installing them in specific places.

Principles of decoding

Each curve on the cardiogram graph has its own elements:

• Teeth, which are convexities directed downwards or upwards. All of them are designated in Latin capital letters. "P" shows the work of the heart's atria. “T” is the restorative capabilities of the myocardium.
• Segments represent the distance between several ascending or descending teeth located in the vicinity. Doctors are especially interested in the indicators of such segments as ST, as well as PQ.
• An interval is a gap that includes both a segment and a tooth.

Each specific element of the ECG shows a specific process that occurs directly in the heart. According to their width, height and other parameters, the doctor is able to correctly decipher the received data.

How are the results analyzed?

As soon as the specialist gets his hands on the electrocardiogram, its interpretation begins. This is done in a certain strict sequence:

1. The correct rhythm is determined by the intervals between the “R” waves. They must be equal. Otherwise, we can conclude that the heart rhythm is incorrect.
2. Using an ECG you can determine your heart rate. To do this, you need to know the speed at which the indicators were recorded. Additionally, you will also need to count the number of cells between the two “R” waves. The norm is from 60 to 90 beats per minute.
3. The source of excitation in the heart muscle is determined by a number of specific signs. This will be revealed, among other things, by assessing the parameters of the “P” wave. The norm implies that the source is the sinus node. Therefore, a healthy person always has sinus rhythm. If a ventricular, atrial or any other rhythm is observed, this indicates the presence of pathology.
4. The specialist evaluates the conductivity of the heart. This happens based on the duration of each segment and tooth.
5. The electrical axis of the heart, if it shifts to the left or right quite sharply, may also indicate the presence of problems with the cardiovascular system.
6. Each tooth, interval and segment is analyzed individually and in detail. Modern ECG machines immediately automatically provide indicators of all measurements. This greatly simplifies the doctor’s work.
7. Finally, the specialist makes a conclusion. It indicates the decoding of the cardiogram. If any pathological syndromes were discovered, they must be indicated there.

Normal values ​​for adults

The norm of all indicators of the cardiogram is determined by analyzing the position of the teeth. But the heart rhythm is always measured by the distance between the highest teeth “R” - “R”. Normally they should be equal. The maximum difference can be no more than 10%. Otherwise, this will no longer be the norm, which should be within 60-80 pulsations per minute. If the sinus rhythm is more frequent, then the patient has tachycardia. On the contrary, a slow sinus rhythm indicates a disease called bradycardia.

P-QRS-T intervals will tell you about the passage of an impulse directly through all parts of the heart. The norm is an indicator from 120 to 200 ms. On the graph it looks like 3-5 squares.

By measuring the width from the Q wave to the S wave, you can get an idea of ​​the excitation of the ventricles of the heart. If this is the norm, then the width will be 60-100 ms.

The duration of ventricular contraction can be determined by measuring the QT interval. The norm is 390-450 ms. If it is slightly longer, a diagnosis can be made: rheumatism, ischemia, atherosclerosis. If the interval is shortened, we can talk about hypercalcemia.

What do the teeth mean?

When interpreting an ECG, it is imperative to monitor the height of all teeth. It may indicate the presence of serious heart pathologies:

• The Q wave is an indicator of excitation of the left cardiac septum. The norm is a quarter of the length of the R wave. If it is exceeded, there is a possibility of necrotic myocardial pathology;
• The S wave is an indicator of excitation of those partitions that are located in the basal layers of the ventricles. The norm in this case is 20 mm in height. If there are deviations, this indicates ischemic disease.
• The R wave in the ECG indicates the activity of the walls of all ventricles of the heart. It is recorded in all ECG curves. If there is no activity somewhere, then it makes sense to suspect ventricular hypertrophy.
• The T wave appears in lines I and II, as directed upward. But in the VR curve it is always negative. When the T wave on the ECG is too high and sharp, the doctor suspects hyperkalemia. If it is long and flat, then there is a risk of developing hypokalemia.

Normal pediatric electrocardiogram readings

In childhood, the norm of ECG indicators may differ slightly from the characteristics of an adult:

1. The heart rate of children under 3 years old is about 110 pulsations per minute, and at the age of 3-5 years – 100 beats. This figure is already lower in adolescents - 60-90 pulsations.
2. The normal QRS reading is 0.6-0.1 s.
3. The P wave should normally not be longer than 0.1 s.
4. The electrical axis of the heart in children should remain without any changes.
5. The rhythm is sinus only.
6. On an ECG, the Q-T interval e may exceed 0.4 s, and the P-Q interval should be 0.2 s.

Sinus heart rate in the cardiogram decoding is expressed as a function of heart rate and respiration. This means that the heart muscle contracts normally. In this case, the pulsation is 60-80 beats per minute.

Why are the indicators different?

Often patients are faced with a situation where their ECG readings are different. What is this connected with? To get the most accurate results, there are many factors to consider:

1. Distortions when recording a cardiogram may be due to technical problems. For example, if the results are not correctly merged. And many Roman numerals look the same whether upside down or right upside down. It happens that the graph is cut incorrectly or the first or last tooth is lost.
2. Preliminary preparation for the procedure is important. On the day of the ECG, you should not have a heavy breakfast, it is advisable to even give it up completely. You will have to stop drinking liquids, including coffee and tea. After all, they stimulate the heart rate. Accordingly, the final indicators are distorted. It's best to shower first, but you don't need to apply any body products. Finally, you need to relax as much as possible during the procedure.
3. Incorrect placement of the electrodes cannot be ruled out.

The best way to check your heart is with an electrocardiograph. He will help you carry out the procedure as correctly and accurately as possible. And to confirm the diagnosis indicated by the ECG results, the doctor will always prescribe additional tests.