What does ecg measure. Deciphering a cardiogram in children and adults: general principles, reading the results, an example of decoding. How is electrocardiography performed?

An electrocardiogram is the most accessible, common way to make a diagnosis, even in conditions of emergency intervention in an ambulance situation.

Now every cardiologist in the field team has a portable and lightweight electrocardiograph capable of reading information by fixing on the recorder the electrical impulses of the heart muscle - myocardium at the time of contraction.

Deciphering the ECG is within the power of every even a child, given the fact that the patient understands the basic canons of the heart. Those same teeth on the tape are the peak (response) of the heart to contraction. The more often they are, the faster the myocardial contraction occurs, the smaller they are, the slower the heartbeat occurs, and in fact the transmission of the nerve impulse. However, this is just a general idea.

To make a correct diagnosis, it is necessary to take into account the time intervals between contractions, the height of the peak value, the age of the patient, the presence or absence of aggravating factors, etc.

An ECG of the heart for diabetics, who, in addition to diabetes, also have late cardiovascular complications, allows us to assess the severity of the disease and intervene in time in order to delay further progression of the disease, which can lead to serious consequences in the form of myocardial infarction, pulmonary embolism and etc.

If the pregnant woman had a bad electrocardiogram, then repeated studies are prescribed with possible daily monitoring.

However, it is worth considering the fact that the values ​​on the tape in a pregnant woman will be somewhat different, since in the process of fetal growth, a natural displacement of the internal organs occurs, which are displaced by the expanding uterus. Their heart occupies a different position in the chest area, therefore, there is a shift in the electrical axis.

In addition, the longer the period, the greater the load experienced by the heart, which is forced to work harder in order to satisfy the needs of two full-fledged organisms.

However, you should not worry so much if the doctor, according to the results, reported the same tachycardia, since it is she who can most often be false, provoked either intentionally or out of ignorance by the patient himself. Therefore, it is extremely important to properly prepare for this study.

In order to correctly pass the analysis, it is necessary to understand that any excitement, excitement and experience will inevitably affect the results. Therefore, it is important to prepare yourself in advance.

Invalid

1. Drinking alcohol or any other strong drinks (including energy drinks, etc.)
2. Overeating (best taken on an empty stomach or a light snack before going out)
3. Smoking
4. Use of medicines that stimulate or suppress heart activity, or drinks (such as coffee)
5. Physical activity
6. Stress

It is not uncommon for a patient, being late to the treatment room at the appointed time, to become very worried or frantically rush to the cherished office, forgetting about everything in the world. As a result, his leaf was mottled with frequent sharp teeth, and the doctor, of course, recommended that his patient re-examine. However, in order not to create unnecessary problems, try to calm yourself as much as possible before entering the cardiology room. Moreover, nothing bad will happen to you there.

When the patient is invited, it is necessary to undress behind the screen to the waist (women take off their bra) and lie down on the couch. In some treatment rooms, depending on the alleged diagnosis, it is also required to free the body from below the torso to the underwear.

After that, the nurse applies a special gel to the abduction sites, to which he attaches electrodes, from which multi-colored wires are stretched to the reading machine.

Thanks to special electrodes, which the nurse places at certain points, the slightest cardiac impulse is captured, which is recorded by means of a recorder.

After each contraction, called depolarization, a tooth is displayed on the tape, and at the moment of transition to a calm state - repolarization, the recorder leaves a straight line.

Within a few minutes, the nurse will take a cardiogram.

The tape itself, as a rule, is not given to patients, but is transferred directly to a cardiologist who deciphers. With notes and transcripts, the tape is sent to the attending physician or transferred to the registry so that the patient can pick up the results himself.

But even if you pick up a cardiogram tape, you will hardly be able to understand what is depicted there. Therefore, we will try to slightly open the veil of secrecy so that you can at least a little bit appreciate the potential of your heart.

ECG interpretation

Even on a blank sheet of this type of functional diagnostics, there are some notes that help the doctor with decoding. The recorder, on the other hand, reflects the transmission of an impulse that passes through all parts of the heart over a certain period of time.

To understand these scribbles, it is necessary to know in what order and how exactly the impulse is transmitted.

The impulse, passing through different parts of the heart, is displayed on the tape in the form of a graph, which conditionally displays marks in the form of Latin letters: P, Q, R, S, T

Let's see what they mean.

P value

The electrical potential, going beyond the sinus node, transmits excitation primarily to the right atrium, in which the sinus node is located.

At this very moment, the reading device will record the change in the form of a peak of excitation of the right atrium. After the conduction system - the interatrial bundle of Bachmann passes into the left atrium. Its activity occurs at the moment when the right atrium is already fully covered by excitation.

On the tape, both of these processes appear as the total value of excitation of both right and left atria and are recorded as a P peak.

In other words, the P peak is a sinus excitation that travels along the conduction pathways from the right to the left atria.

Interval P - Q

Simultaneously with the excitation of the atria, the impulse that has gone beyond the sinus node passes along the lower branch of the Bachmann bundle and enters the atrioventricular junction, which is otherwise called atrioventricular.

This is where the natural delay occurs. Therefore, a straight line appears on the tape, which is called isoelectric.

In evaluating the interval, the time it takes for the impulse to pass through this connection and subsequent departments plays a role.

The count is in seconds.

Complex Q, R, S

After the impulse, passing along the conducting paths in the form of a bundle of His and Purkinje fibers, reaches the ventricles. This whole process is presented on the tape as a QRS complex.

The ventricles of the heart are always excited in a certain sequence, and the impulse travels this path in a certain amount of time, which also plays an important role.

Initially, the septum between the ventricles is covered by excitation. This takes about 0.03 sec. A Q wave appears on the chart, extending just below the main line.

After the impulse for 0.05. sec. reaches the apex of the heart and adjacent areas. A high R wave forms on the tape.

After that, it moves to the base of the heart, which is reflected in the form of a falling S wave. This takes 0.02 seconds.

Thus, the QRS is an entire ventricular complex with a total duration of 0.10 seconds.

S-T interval

Since myocardial cells cannot be in excitation for a long time, there comes a moment of decline when the impulse fades. By this time, the process of restoring the original state that prevailed before the excitement starts.

This process is also recorded on the ECG.

By the way, in this case, the initial role is played by the redistribution of sodium and potassium ions, the movement of which gives this same impulse. All this is called in one word - the process of repolarization.

We will not go into details, but only note that this transition from excitation to extinction is visible from the S to the T wave.

ECG norm

These are the main designations, looking at which one can judge the speed and intensity of the beating of the heart muscle. But in order to get a more complete picture, it is necessary to reduce all the data to some single standard of the ECG norm. Therefore, all devices are configured in such a way that the recorder first draws control signals on the tape, and only then begins to pick up electrical vibrations from the electrodes connected to the person.

Typically, such a signal is equal in height to 10 mm and 1 millivolt (mV). This is the same calibration, control point.

All measurements of the teeth are made in the second lead. On the tape, it is indicated by the Roman numeral II. The R wave must correspond to the control point, and based on it, the rate of the remaining teeth is calculated:

• height T 1/2 (0.5 mV)
• depth S - 1/3 (0.3 mV)
• height P - 1/3 (0.3 mV)
• depth Q - 1/4 (0.2 mV)

The distance between teeth and intervals is calculated in seconds. Ideally, look at the width of the P wave, which is equal to 0.10 sec, and the subsequent length of the teeth and intervals is equal to 0.02 sec each time.

Thus, the width of the P wave is 0.10±0.02 sec. During this time, the impulse will cover both atria with excitation; P - Q: 0.10±0.02 sec; QRS: 0.10±0.02 sec; for passing a full circle (excitation passing from the sinus node through the atrioventricular connection to the atria, ventricles) in 0.30 ± 0.02 sec.

Let's look at a few normal ECGs for different ages (in a child, in adult men and women)

It is very important to take into account the age of the patient, his general complaints and condition, as well as current health problems, since even the slightest cold can affect the results.

Moreover, if a person goes in for sports, then his heart “gets used” to work in a different mode, which affects the final results. An experienced doctor always takes into account all relevant factors.

ECG norm of a teenager (11 years old). For an adult, this will not be the norm.

The norm of the ECG of a young man (age 20 - 30 years).

The description of the resulting diagram is made according to a certain template:

• An assessment of the heart rate is carried out with the measurement of heart rate (heart rate) at the norm: the rhythm is sinus, the heart rate is 60-90 beats per minute.
• Calculation of intervals: Q-T at a rate of 390 - 440 ms.

This is necessary to estimate the duration of the contraction phase (they are called systoles). In this case, Bazett's formula is used. An extended interval indicates coronary heart disease, atherosclerosis, myocarditis, etc. A short interval may be associated with hypercalcemia.

• Assessment of the electrical axis of the heart (EOS)

This parameter is calculated from the isoline, taking into account the height of the teeth. In a normal heart rhythm, the R wave should always be higher than S. If the axis deviates to the right, and S is higher than R, then this indicates disorders in the right ventricle, with a deviation to the left in leads II and III - left ventricular hypertrophy.

• Q-R-S Complex Assessment

Normally, the interval should not exceed 120 ms. If the interval is distorted, then this may indicate various blockades in the conductive pathways (peduncles in the bundles of His) or conduction disturbances in other areas. According to these indicators, hypertrophy of the left or right ventricles can be detected.

• an inventory of the S-T segment is being conducted

It can be used to judge the readiness of the heart muscle to contract after its complete depolarization. This segment should be longer than the Q-R-S complex.

What do Roman numerals on an ECG mean?

Each point to which the electrodes are connected has its own meaning. It captures electrical vibrations and the recorder reflects them on the tape. In order to correctly read the data, it is important to correctly install the electrodes on a specific area.

For example:

• the potential difference between two points of the right and left hand is recorded in the first lead and is denoted by I
• the second lead is responsible for the potential difference between the right arm and left leg - II
• the third between the left hand and left foot - III

If we mentally connect all these points, then we get a triangle, named after the founder of electrocardiography, Einthoven.

In order not to confuse them with each other, all electrodes have wires of different colors: red is attached to the left hand, yellow to the right, green to the left leg, black to the right leg, it acts as a ground.

This arrangement refers to a bipolar lead. It is the most common, but there are also single-pole circuits.

Such a single-pole electrode is indicated by the letter V. The recording electrode, mounted on the right hand, is indicated by the sign VR, on the left, respectively, VL. On the leg - VF (food - leg). The signal from these points is weaker, so it is usually amplified, there is an “a” mark on the tape.

The chest leads are also slightly different. The electrodes are attached directly to the chest. Receiving impulses from these points is the strongest, clearest. They don't require amplification. Here the electrodes are arranged strictly according to the agreed standard:

The standard study uses 12 leads.

How to identify pathologies in the work of the heart

When answering this question, the doctor pays attention to the diagram of a person and, according to the main designations, he can guess which particular department began to fail.

We will display all the information in the form of a table.

Considering all of the above, you can learn how to decipher the tape at least according to the simplest parameters. Although many serious deviations in the work of the heart will be visible to the naked eye, even with this set of knowledge.

For clarity, we will describe some of the most disappointing diagnoses so that you can simply visually compare the norm and deviations from it.

myocardial infarction

Judging by this ECG, the diagnosis will be disappointing. Here, from the positive, only the duration of the Q-R-S interval, which is normal.

In leads V2 - V6 we see ST elevation.

This is the result acute transmural ischemia(AMI) of the anterior wall of the left ventricle. Q waves are seen in the anterior leads.

On this tape, we see a conduction disturbance. However, even with this fact, acute anterior-septal myocardial infarction against the background of blockade of the right leg of the bundle of His.

The right chest leads dismantle the S-T elevation and positive T waves.

Rimm - sinus. Here, there are high regular R waves, the pathology of the Q waves in the posterolateral sections.

Visible deviation ST in I, aVL, V6. All this indicates a posterolateral myocardial infarction with coronary heart disease (CHD).

Thus, the signs of myocardial infarction on the ECG are:

• tall T wave
• elevation or depression of the S-T segment
• pathological Q wave or its absence

Signs of myocardial hypertrophy

Ventricular

For the most part, hypertrophy is characteristic of those people whose heart has experienced additional stress for a long time as a result of, say, obesity, pregnancy, some other disease that negatively affects the non-vascular activity of the whole organism as a whole or individual organs (in particular, lungs, kidneys).

The hypertrophied myocardium is characterized by several signs, one of which is an increase in the time of internal deflection.

What does it mean?

Excitation will have to spend more time passing through the cardiac departments.

The same applies to the vector, which is also larger, longer.

If you look for these signs on the tape, then the R wave will be higher in amplitude than normal.

A characteristic symptom is ischemia, which is the result of insufficient blood supply.

Through the coronary arteries to the heart there is a blood flow, which, with an increase in the thickness of the myocardium, encounters an obstacle on the way and slows down. Violation of the blood supply causes ischemia of the subendocardial layers of the heart.

Based on this, the natural, normal function of the pathways is disrupted. Inadequate conduction leads to failures in the process of excitation of the ventricles.

After that, a chain reaction is launched, because the work of other departments depends on the work of one department. If there is hypertrophy of one of the ventricles on the face, then its mass increases due to the growth of cardiomyocytes - these are cells that are involved in the process of transmitting a nerve impulse. Therefore, its vector will be larger than the vector of a healthy ventricle. On the tape of the electrocardiogram, it will be noticeable that the vector will be deviated towards the localization of hypertrophy with a shift in the electrical axis of the heart.

The main features include a change in the third chest lead (V3), which is something like a transshipment, transition zone.

What kind of zone is this?

It includes the height of the R tooth and the depth S, which are equal in their absolute value. But when the electrical axis changes as a result of hypertrophy, their ratio will change.

Consider specific examples

In sinus rhythm, left ventricular hypertrophy is clearly visible with characteristic high T waves in the chest leads.

There is nonspecific ST depression in the inferolateral region.

EOS (electrical axis of the heart) deviated to the left with an anterior hemiblock and prolongation of the QT interval.

High T waves indicate that a person has, in addition to hypertrophy, also hyperkalemia most likely developed against the background of renal failure and, which are characteristic of many patients who have been ill for many years.

In addition, a longer QT interval with ST depression indicates hypocalcemia that progresses in advanced stages (chronic renal failure).

This ECG corresponds to an elderly person who has serious kidney problems. He is on the edge.

atrial

As you already know, the total value of atrial excitation on the cardiogram is shown by the P wave. In case of failures in this system, the width and / or height of the peak increases.

With right atrial hypertrophy (RAA), P will be higher than normal, but not wider, since the peak of the excitation of the PP ends before the excitation of the left. In some cases, the peak takes on a pointed shape.

With HLP, there is an increase in the width (more than 0.12 seconds) and height of the peak (double-hump appears).

These signs indicate a violation of the conduction of the impulse, which is called intra-atrial blockade.

blockades

Blockades are understood as any failures in the conduction system of the heart.

A little earlier, we looked at the path of the impulse from the sinus node through the conducting paths to the atria, at the same time, the sinus impulse rushes along the lower branch of the Bachmann bundle and reaches the atrioventricular junction, passing through it, it undergoes a natural delay. Then it enters the conduction system of the ventricles, presented in the form of His bundles.

Depending on the level at which the failure occurred, a violation is distinguished:

• intra-atrial conduction (sinus impulse block in the atria)
• atrioventricular
• intraventricular

Intraventricular conduction

This system is presented in the form of a trunk of His, divided into two branches - the left and right legs.

The right leg "supplies" the right ventricle, inside which it branches into many small networks. It appears as one wide bundle with branches inside the muscles of the ventricle.

The left leg is divided into anterior and posterior branches, which "adjoin" the anterior and posterior wall of the left ventricle. Both of these branches form a network of smaller branches within the LV musculature. They are called Purkinje fibers.

Blockade of the right leg of the bundle of His

The course of the impulse first covers the path through the excitation of the interventricular septum, and then the first unblocked LV is involved in the process, through its normal course, and only after that the right one is excited, to which the impulse reaches the distorted path through the Purkinje fibers.

Of course, all this will affect the structure and shape of the QRS complex in the right chest leads V1 and V2. At the same time, on the ECG we will see bifurcated peaks of the complex, similar to the letter "M", in which R is the excitation of the interventricular septum, and the second R1 is the actual excitation of the pancreas. S, as before, will be responsible for the excitation of the left ventricle.

On this tape we see incomplete RBBB and 1st degree AB block, there are also p ubtsovye changes in the posterior diaphragmatic region.

Thus, the signs of blockade of the right leg of the bundle of His are as follows:

• elongation of the QRS complex in standard lead II for more than 0.12 sec.
• an increase in the time of internal deflection of the right ventricle (on the graph above, this parameter is presented as J, which is more than 0.02 sec in the right chest leads V1, V2)
• deformation and splitting of the complex into two "humps"
• negative T wave

Blockade of the left leg of the bundle of His

The course of excitation is similar, the impulse reaches the LV through detours (it does not pass along the left leg of the His bundle, but through the network of Purkinje fibers from the pancreas).

Characteristic features of this phenomenon on the ECG:

• widening of the ventricular QRS complex (more than 0.12 sec)
• an increase in the time of internal deviation in the blocked LV (J is greater than 0.05 sec)
• deformation and bifurcation of the complex in leads V5, V6
• negative T wave (-TV5, -TV6)

Blockade (incomplete) of the left leg of the bundle of His

It is worth paying attention to the fact that the S wave will be “atrophied”, i.e. he will not be able to reach the isoline.

Atrioventricular block

There are several degrees:

• I - slow conduction is characteristic (heart rate is normal within 60 - 90; all P waves are associated with the QRS complex; P-Q interval is more than normal 0.12 sec.)
• II - incomplete, divided into three options: Mobitz 1 (heart rate slows down; not all P waves are associated with the QRS complex; the P-Q interval changes; periodicals appear 4:3, 5:4, etc.), Mobitz 2 (also most, but the interval P - Q is constant; periodicity 2:1, 3:1), high-grade (significantly reduced heart rate; periodicity: 4:1, 5:1; 6:1)
• III - complete, divided into two options: proximal and distal

Well, we will go into details, but only note the most important:

• the time of passage through the atrioventricular junction is normally 0.10±0.02. Total, no more than 0.12 sec.
• reflected on the interval P - Q
• here there is a physiological impulse delay, which is important for normal hemodynamics

AV block II degree Mobitz II

Such violations lead to failures of intraventricular conduction. Usually people with such a tape have shortness of breath, dizziness, or they quickly overwork. In general, this is not so scary and is very common even among relatively healthy people who do not particularly complain about their health.

Rhythm disturbance

Signs of arrhythmia are usually visible to the naked eye.

When excitability is disturbed, the response time of the myocardium to the impulse changes, which creates characteristic graphs on the tape. Moreover, it should be understood that not in all cardiac departments the rhythm can be constant, taking into account the fact that there is, say, some kind of blockade that inhibits the transmission of impulses and distorts signals.

So, for example, the following cardiogram indicates atrial tachycardia, and the one below it indicates ventricular tachycardia with a frequency of 170 beats per minute (LV).

The sinus rhythm with a characteristic sequence and frequency is correct. Its characteristics are as follows:

• frequency of P waves in the range of 60-90 per minute
• RR spacing is the same

• the P wave is positive in the II standard lead
• P wave is negative in lead aVR

Any arrhythmia indicates that the heart is working in a different mode, which cannot be called regular, habitual and optimal. The most important thing in determining the correctness of the rhythm is the uniformity of the interval of the P-P waves. Sinus rhythm is correct when this condition is met.

If there is a slight difference in the intervals (even 0.04 sec, not exceeding 0.12 sec), then the doctor will already indicate a deviation.

The rhythm is sinus, irregular, since the RR intervals differ by no more than 0.12 sec.

If the intervals are more than 0.12 seconds, then this indicates an arrhythmia. It includes:

• extrasystole (most common)
• paroxysmal tachycardia
• flicker
• flutter, etc.

Arrhythmia has its own focus of localization, when a rhythm disturbance occurs in certain parts of the heart (in the atria, ventricles) on the cardiogram.

The most striking sign of atrial flutter is high-frequency impulses (250 - 370 beats per minute). They are so strong that they overlap the frequency of sinus impulses. There will be no P waves on the ECG. In their place, sharp, sawtooth low-amplitude “teeth” (no more than 0.2 mV) will be visible on lead aVF.

ECG Holter

This method is otherwise abbreviated as HM ECG.

What it is?

Its advantage is that it is possible to carry out daily monitoring of the work of the heart muscle. The reader itself (recorder) is compact. It is used as a portable device capable of recording signals from electrodes on a magnetic tape for a long period of time.

On a conventional stationary device, it is quite difficult to notice some intermittent jumps and malfunctions in the work of the myocardium (given the asymptomaticity) and the Holter method is used to make sure the diagnosis is correct.

The patient is invited to keep a detailed diary on his own after medical instructions, since some pathologies can manifest themselves at a certain time (the heart “collapses” only in the evenings and then not always, in the mornings something “presses” on the heart).

While observing, a person writes down everything that happens to him, for example: when he was at rest (sleep), overworked, ran, quickened his pace, worked physically or mentally, was nervous, worried. At the same time, it is also important to listen to yourself and try to describe as clearly as possible all your feelings, symptoms that accompany certain actions, events.

The time of data collection usually lasts no longer than a day. For such daily monitoring of the ECG allows you to get a clearer picture and determine the diagnosis. But sometimes the data collection time can be extended to several days. It all depends on the person's well-being and the quality and completeness of previous laboratory tests.

Usually, the basis for prescribing this type of analysis is the painless symptoms of coronary heart disease, latent hypertension, when doctors have suspicions, doubts about any diagnostic data. In addition, they can prescribe it when prescribing new drugs for the patient that affect the functioning of the myocardium, which are used in the treatment of ischemia or if there is an artificial pacemaker, etc. This is also done in order to assess the patient's condition in order to assess the degree of effectiveness of the prescribed therapy, and so on.

How to prepare for HM ECG

Usually there is nothing complicated in this process. However, it should be understood that other devices, especially emitting electromagnetic waves, can affect the device.

Interaction with any metal is also not desirable (rings, earrings, metal buckles, etc. should be removed). The device must be protected from moisture (complete body hygiene under the shower or bath is unacceptable).

Synthetic fabrics also negatively affect the results, as they can create static voltage (they become electrified). Any such “splash” from clothes, bedspreads and other things distorts the data. Replace them with natural ones: cotton, linen.

The device is extremely vulnerable and sensitive to magnets, do not stand near a microwave oven or an induction hob, avoid being near high-voltage wires (even if you drive a car through a small section of the road over which high-voltage lines lie).

How is data collected?

Usually, the patient is given a referral, and at the appointed time he comes to the hospital, where the doctor, after some theoretical introductory course, installs electrodes on certain parts of the body, which are connected by wires to a compact recorder.

The registrar itself is a small device that captures any electromagnetic vibrations and remembers them. It fastens on the belt and hides under the clothes.

Men sometimes have to shave in advance some parts of the body on which the electrodes are attached (for example, to “free” the chest from hair).

After all preparations and installation of equipment, the patient can go about his usual activities. He should merge into his daily life as if nothing had happened, though not forgetting to take notes (it is extremely important to indicate the time of manifestation of certain symptoms and events).

After the period set by the doctor, the “subject” returns to the hospital. The electrodes are removed from it and the reading device is taken away.

The cardiologist, using a special program, will process the data from the recorder, which, as a rule, is easily synchronized with a PC and will be able to make a specific inventory of all the results obtained.

Such a method of functional diagnostics as an ECG is much more effective, since thanks to it even the slightest pathological changes in the work of the heart can be noticed, and it is widely used in medical practice in order to identify life-threatening diseases in patients like a heart attack.

It is especially important for diabetics with cardiovascular late complications that have developed against the background of diabetes mellitus to undergo it periodically at least once a year.

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ELECTROCARDIOGRAM

ELECTROCARDIOGRAM -s; and. Graphic image of the work of the heart, made by an electrocardiograph. Make an electrocardiogram. / Razg. About the state of the heart, about the work of the heart. Bad e. Satisfactory e. E. got better.

ELECTROCARDIOGRAM (ECG), a curve reflecting the bioelectrical activity of the heart.
When the heart is excited, a potential difference arises on its surface and in its tissues, which naturally changes in magnitude and direction as new parts of the heart are involved in the excitation. The bioelectrical activity of different parts of the heart occurs in a strictly defined sequence, repeated in each cardiac cycle of excitation. The resulting changes in the charges of the surface of the heart create a dynamic electric field in the surrounding heart of the conductive medium, which can be registered from the surface of the body after appropriate amplification in the form of a variable potential difference. In this case, a characteristic curve is obtained, consisting of several teeth separated by certain intervals. This curve is called the electrocardiogram - ECG. The ECG teeth are denoted by the Latin letters P, Q, R, S and T, and the corresponding intervals, or segments, are P-Q, S-T, Q-T. ECG waves and intervals reflect activation and recovery processes in different parts of the heart.
History of electrocardiography
For the first time, the presence of electrical phenomena in the contracting heart of a frog was suggested by the German researchers A. Kölliker and G. Müller (1856), who, when a nerve approaching a muscle was applied to the heart, observed a rhythmic contraction of the skeletal muscle in time with the heart. In 1862 I. M. Sechenov (cm. Sechenov Ivan Mikhailovich) In the monograph "On Animal Electricity" he wrote that when the nerve of the "moving apparatus" of the frog is applied to the ventricle of the heart of a rabbit, "the muscle of the frog apparatus shudders with each systole of the ventricle." This is the first known mention of the presence of electrical phenomena in the heart of warm-blooded animals. The first instrumental recording of the electrical activity of the heart in a turtle and a frog was made by Moray in 1876 using a Lipman capillary electrometer. The first human ECG was recorded in 1887 by the English researcher A. Waller using a capillary electrometer. Waller placed electrodes for recording potentials on the torso (chest and back) and on the limbs of a person. Later, the same researcher published a method for recording ECG in animals (dog, cat, horse). He taught his pets to stand quietly in baths of water to ensure reliable contact of the integument with the recording equipment, and in all animals he obtained the same type of curves. The method of ECG derivation from the limbs subsequently at the suggestion of the Dutch scientist V. Einthoven (cm. EINTHOVEN Willem) became universal, standard. In his research, V. Einthoven used a more advanced string galvanometer, which made it possible to record ECG in its modern expression, he also introduced the term "electrocardiogram" into practice at the very beginning of the century, gave the designation to the teeth and intervals of the ECG, introduced standard leads, developed the first theory of genesis electrocardiograms. In Russia, the introduction of the electrocardiographic method is associated with the work of A.F. Samoilov (cm. SAMOILOV Alexander Filippovich), who introduced the term ECG into practice and created one of the theories of the genesis of the electrocardiogram.
Connection of excitation of heart structures with ECG waves and intervals.
In the heart of warm-blooded and human beings, excitation occurs in the sinoauricular node (in the frog's heart, the sinus node). On the ECG, the excitation of this node is not recorded, it is detected only by special methods. The beginning of atrial excitation corresponds to the P wave of the ECG. It is followed by the P-Q interval, during this time there is a transfer of excitation to the atrioventricular node. The QRS complex corresponds to excitation coverage of the working myocardium of the ventricles. After the QRS complex, the S-T isoelectric interval is recorded, during which the entire surface of the ventricles remains excited. Normally, the S-T segment deviates from the isoelectric level by no more than 0.1 mV.
The beginning of the recovery process in the ventricles corresponds to the appearance of the T wave, with the end of which the recovery is completely completed. After the T wave, an isoelectric interval is recorded corresponding to the relaxation of the heart.
ECG lead methods
The magnitude of the potential difference captured by the electrodes depends on the distance from the electrodes to the heart, the degree of electrical conductivity of the tissue between the heart and the electrodes, and the mass of the excited elements of the heart that generate the electromotive force. Therefore, in order to be able to compare and compare the ECG of different people or to trace the dynamics of changes in the ECG of the same person, it was necessary to standardize the methods of assignment. For this purpose, the electrodes are applied to strictly defined areas of the body - depending on this, they speak of one or another method of abduction. The main methods are limb leads, or standard leads, and unipolar chest leadsՑڐخ
In the clinic and in physiological experiments, a number of other methods of recording ECG are used: unipolar leads from the limbs and chest, esophageal leads (the active electrode is localized in the esophagus in the region of the location of certain parts of the heart), intracavitary leads (the electrode is used as the active electrode). catheter, which is inserted through the jugular vein into the cavity of the heart), etc.
ECG standards
The amplitude and duration of the waves, as well as the magnitude of the ECG intervals, naturally change with various physical and physiological effects on the heart - during physical activity, changes in body position, etc. These changes can be due, on the one hand, to purely physical phenomena, for example, a change in the position of the heart in the chest during breathing, when changing posture, a change in the electrical conductivity of the tissues between the heart and the discharge electrodes during breathing. On the other hand, they can also be caused by physiological reasons: changes in venous inflow, reflex effects on the work of the heart and on the speed of conduction in it.
Thus, with the normal functioning of the heart, the shape of the ECG can vary within certain limits. In this regard, an indispensable condition for the correct interpretation of the ECG in various types of cardiac pathology is the ability to recognize the normal electrocardiographic curve in all its varieties. Normal ECG variants can be found in various clinical references and electrocardiography textbooks.
With various pathologies of the heart, the form of the ECG deviates significantly from the above standards. The most striking reflection on the ECG is obtained by pathological processes associated with violations of the rhythmic activity of the heart (extrasystole (cm. extrasystole), fibrillation, etc.), excitation (blockade of the bundle legs), the occurrence of ischemic foci ECG allows you to diagnose various forms of myocardial infarction and monitor the process of restoring coronary circulation in the postinfarction period.

encyclopedic Dictionary. 2009 .

See what "ELECTROCARDIOGRAM" is in other dictionaries:

Electrocardiogram ... Spelling Dictionary

- (ECG), a record of the electrical activity of the heart, performed using a device on a moving strip of paper. An instrument used for this purpose is called an electrocardiograph. An EKG is used to diagnose heart disease... Scientific and technical encyclopedic dictionary

Exist., number of synonyms: 3 cardiogram (8) normogram (1) ecg (1) ... Synonym dictionary

electrocardiogram- — [Ya.N. Luginsky, M.S. Fezi Zhilinskaya, Yu.S. Kabirov. English Russian Dictionary of Electrical Engineering and Power Engineering, Moscow, 1999] Electrical engineering topics, basic concepts EN electrocardiogram ... Technical Translator's Handbook

Electrocardiography is a technique for recording and studying electric fields generated during the work of the heart. Electrocardiography is a relatively inexpensive but valuable method of electrophysiological instrumental diagnostics in ... ... Wikipedia

- (see electro ...) graphic recording of electrical phenomena occurring in the heart during its work cf. cardiogram). New dictionary of foreign words. by EdwART, 2009. electrocardiogram med. the curve of recording the activity of the heart, obtained ... ... Dictionary of foreign words of the Russian language

- (electro + cardiogram; ECG; syn. actinocardiogram obsolete) curve reflecting changes in time of the potential difference of the electric field (biopotentials) of the heart during its contractions ... Big Medical Dictionary

- (from Electro ..., Cardio ... and ... a curve written on paper, reflecting fluctuations in the biopotentials of a beating heart. See Electrocardiography ... Great Soviet Encyclopedia

G. Graphical recording of the work of the heart, made by an electrocardiograph. Explanatory Dictionary of Ephraim. T. F. Efremova. 2000... Modern explanatory dictionary of the Russian language Efremova

Electrocardiogram, electrocardiogram, electrocardiogram, electrocardiogram, electrocardiogram, electrocardiogram, electrocardiogram, electrocardiogram, electrocardiogram, electrocardiogram, electrocardiogram, ... ... Word forms

Books

• Electrocardiogram with an artificial pacemaker, S. Grigorov. The monograph on electrocardiography presents data on the electrical stimulation of the heart, the methods used and the types of electrical stimulators. ECGs were considered during the functioning of each ...

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.

The purpose of conducting ECG studies:

• assessment of the most important cardiac functions: automatism, excitability, conduction;
• 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 course of myocardial infarction;
• detection of violations of conduction and heart rhythm;
• detection of other cardiac pathologies (pericarditis, electrolyte and metabolic disorders of the myocardium, etc.).

Options for ECG studies can be divided into two classes:

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

Conducting ECG studies at rest is described in detail in the ECG section.

VEM, Treadmill test

Both of these tests are similar in nature - the measurement of the electrical activity of the heart during exercise on a bicycle ergometer or treadmill (treadmill).

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

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 pectoris, an excessive rise (fall) in blood pressure, and loss of consciousness of the patient.

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

Indications for the treadmill test (VEM):

• in healthy people:
  • determination of tolerance to physical activity;
  • professional selection;
  • identification of individuals at risk of developing hypertension, when blood pressure rises sharply during exercise;
  • identification of the initial manifestations of atherosclerotic lesions of the coronary arteries and coronary artery disease;
  • detection of latent insufficiency of cardiac blood supply with high cholesterol.
• in persons with diseases of the heart and blood vessels:
  • detection and identification of arrhythmias;
  • detection 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 ongoing therapeutic measures in patients who have undergone MI;
  • examination of the working capacity of patients with diseases of the heart and blood vessels.

Absolute contraindications for the 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 termination of the treadmill test (TEM):

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

ECG termination criteria for 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 seconds 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 with heart rate over 130 bpm);
• elevation of the ST segment by 1 mm or more compared to the original;
• development of arrhythmias: extrasystoles (more than 1:10 extrasystoles), paroxysmal tachycardia, atrial fibrillation;
• violation of cardiac conduction - the appearance (progression) of AV blockade, blockade of the legs of the bundle of His;
• change in the QRS complex: R wave volts increased by more than a third; deepening (expansion) of the q waves (qR); transition of the Q wave to QS;
• development of the WPW syndrome, migration of the pacemaker through the atria.

Rice. Ischemic displacement of the ST segment: a) horizontal; b) skew-down; c) trough-shaped.

Rice. Obliquely ascending displacements of the ST segment: a) there is no displacement; b) displacement 2 mm.

Rice. ST segment elevation options: a) at rest; b) at the peak of physical activity.

Evaluation of the results of the treadmill test (VEM)

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;
• medicines that the patient took on the eve of the test;
• data on the magnitude of the load, the duration of work at each stage of the test;
• test results recorded by the doctor:
• reason for terminating 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 tests with physical activity:

• negative test: the subject reached "his" age-related heart rate, while no clinical or electrocardiographic signs of ischemia (myocardial dysfunction) were recorded;
• negative test with features: upon reaching the age-related heart rate, extrasystole is recorded less than 4 per 1 minute; dizziness, headache, shortness of breath, calf pain; a 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, are associated with the patient's lack of training, lack of experience in performing heavy physical exertion;
• positive test: ECG criteria for the presence of myocardial ischemia are recorded, regardless of the simultaneous development (absence) of angina attacks;
• doubtful sample:
  • the patient in the chest developed a pain syndrome characteristic of angina pectoris, 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 by 20 mm Hg was recorded. Art. and more.
• invalid sample: it was not possible to achieve the required age level of heart rate in the patient.

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An electrocardiograph (ECG) is a device that allows you to evaluate cardiac activity, as well as to diagnose the state of this organ. During the examination, the doctor receives data in the form of a curve. How to read an ECG trace? What are the types of teeth? What changes are visible on the ECG? Why do doctors need this diagnostic method? What does the ECG show? These are far from all the questions that interest people who are faced with electrocardiography. First you need to know how the heart works.

The human heart consists of two atria and two ventricles. The left side of the heart is more developed than the right, as it has a greater load. It is this ventricle that most often suffers. Despite the difference in size, both sides of the heart must work stably, harmoniously.

Learning to read an electrocardiogram on your own

How to read an ECG correctly? This is not as difficult to do as it might seem at first glance. First you need to look at the cardiogram. It is printed on special paper with cells, and two types of cells are clearly visible: large and small.

The conclusion of the ECG is read by these cells. teeth, cells These are the main parameters of the cardiogram. Let's try to learn how to read an ECG from scratch.

Meaning of cells (cells)

There are two types of cells on the paper for printing the examination result: large and small. All of them consist of vertical and horizontal guides. Vertical is voltage, and horizontal is time.

Large squares consist of 25 small cells. Each small cell is 1 mm and corresponds to 0.04 seconds in the horizontal direction. Large squares are 5 mm and 0.2 seconds. In the vertical direction, a centimeter of the strip is equal to 1 mV of voltage.

teeth

There are five teeth in total. Each of them on the graph displays the work of the heart.

1. P - Ideally, this tooth should be positive in the range from 0.12 to two seconds.
2. Q - negative wave, shows the state of the interventricular septum.
3. R - displays the state of the myocardium of the ventricles.
4. S - negative wave, shows the completion of processes in the ventricles.
5. T - positive wave, shows the restoration of potential in the heart.

All ECG teeth have their own reading characteristics.

Prong P

All teeth of the electrocardiogram are of some importance for the correct diagnosis.

The very first tooth of the graph is called P. It denotes the time between heartbeats. To measure it, it is best to highlight the beginning and end of the tooth and then count the number of small cells. Normally, the P wave should be between 0.12 and 2 seconds.

However, measuring this indicator in only one area will not give accurate results. To make sure that the heartbeat is even, it is necessary to determine the interval of the P wave in all areas of the electrocardiogram.

R wave

Knowing how to read an ECG in an easy way, you can understand if there are heart pathologies. The next important tooth on the graph is R. It is easy to find - this is the highest peak on the graph. This will be the positive wave. Its highest part is marked on the R cardiogram, and its lower parts are Q and S.

The QRS complex is called the ventricular or sinus complex. In a healthy person, the sinus rhythm on the ECG is narrow, high. The ECG R waves are clearly visible in the figure, they are the highest:

Between these peaks, the number of large squares points to This indicator is calculated using the following formula:

300/number of large squares = heart rate.

For example, there are four full squares between the peaks, then the calculation will look like this:

300/4=75 heart beats per minute.

Sometimes on the cardiogram there is an elongation of the QRS complex for more than 0.12 s, which indicates a blockade of the bundle of His.

PQ wave interval

PQ is the interval from the P wave to Q. It corresponds to the time of excitation through the atria to the ventricular myocardium. The norm of the PQ interval at different ages is different. Usually it is 0.12-0.2 s.

With age, the interval increases. So, in children under 15 years of age, PQ can reach 0.16 s. At the age of 15 to 18 years, PQ increases to 0.18 s. In adults, this indicator is equal to a fifth of a second (0.2).

When the interval is extended to 0.22 s, they speak of bradycardia.

Interval between QT waves

If this complex is longer, then we can assume coronary artery disease, myocarditis or rheumatism. With a shortened type, hypercalcemia may occur.

ST interval

Normally, this indicator is located at the level of the midline, but may be two cells higher than it. This segment shows the process of restoration of depolarization of the heart muscle.

In rare cases, the indicator can rise three cells above the midline.

Norm

The decoding of the cardiogram normally should look like this:

• The Q and S segments should always be below the midline, i.e. negative.
• The R and T waves should normally be located above the midline, i.e., they will be positive.
• The QRS complex should be no wider than 0.12 s.
• Heart rate should be between 60 and 85 beats per minute.
• There should be sinus rhythm on the ECG.
• The R must be above the S wave.

ECG in pathologies: sinus arrhythmia

And how to read an ECG for various pathologies? One of the most common heart diseases is sinus rhythm disorder. It can be pathological and physiological. The latter type is usually diagnosed in people involved in sports, with neuroses.

With sinus arrhythmia, the cardiogram has the following form: sinus rhythms are preserved, fluctuations in the R-R intervals are observed, but during the breath hold the graph is even.

With pathological arrhythmia, the preservation of the sinus impulse is observed constantly, regardless of breath holding, while wave-like changes are observed at all R-R intervals.

The manifestation of a heart attack on the ECG

When a myocardial infarction occurs, the changes on the ECG are pronounced. Signs of pathology are:

• increase in heart rate;
• the ST segment is elevated;
• there is a fairly persistent depression in the ST leads;
• the QRS complex increases.

In case of a heart attack, the cardiogram is the main means of recognizing the zones of necrosis of the heart muscle. With its help, you can determine the depth of damage to the organ.

In a heart attack, the ST segment is elevated on the graph, and the R wave will be lowered, giving the ST a cat-like shape. Sometimes with pathology, changes in the Q wave can be observed.

Ischemia

When it occurs, you can see in which part it is located.

• Location of ischemia at the anterior wall of the left ventricle. Diagnosed with symmetrical peaked T-teeth.
• Location near the epicardium of the left ventricle. The T-tooth is pointed, symmetrical, directed downwards.
• Transmural type of left ventricular ischemia. T pointed, negative, symmetrical.
• Ischemia in the myocardium of the left ventricle. T is smoothed, slightly raised up.
• Damage to the heart is indicated by the state of the T wave.

Changes in the ventricles

An ECG shows changes in the ventricles. Most often they appear in the left ventricle. This type of cardiogram occurs in people with prolonged additional stress, such as obesity. With this pathology, the electric axis deviates to the left, against which the S wave becomes higher than R.

Holter Method

But how to learn to read an ECG, if it is not always clear which teeth are located and how? In such cases, continuous registration of the cardiogram using a mobile device is prescribed. It constantly records ECG data on a special tape.

This method of examination is necessary in cases where the classical ECG fails to detect pathologies. During the diagnosis of Holter, a detailed diary is necessarily kept, where the patient records all his actions: sleep, walks, sensations during activity, all activity, rest, symptoms of the disease.

Typically, data registration occurs within a day. However, there are cases when it is necessary to take readings up to three days.

ECG decoding schemes

1. The conduction and rhythm of the heart is analyzed. To do this, the regularity of heart contractions is assessed, the number of heart rates is calculated, and the conduction system is determined.
2. Axial rotations are detected: the position of the electric axis in the frontal plane is determined; around the transverse longitudinal axis.
3. The R wave is analyzed.
4. The QRS-T is analyzed. At the same time, the state of the QRS complex, RS-T, T wave, as well as the Q-T interval are assessed.
5. A conclusion is made.

According to the duration of the R-R cycle, they speak about the regularity and norm of the heart rhythm. When evaluating the work of the heart, not one R-R interval is evaluated, but all. Normally, deviations within 10% of the norm are allowed. In other cases, an irregular (pathological) rhythm is determined.

To establish the pathology, the QRS complex and a certain period of time are taken. It counts how many times the segment is repeated. Then the same period of time is taken, but further on the cardiogram, it is again calculated. If at equal time intervals the number of QRS is the same, then this is the norm. At different amounts, pathology is assumed, while P waves are oriented. They should be positive and stand in front of the QRS complex. Throughout the graph, the shape of P should be the same. This option indicates sinus rhythm of the heart.

With atrial rhythms, the P wave is negative. Behind it is the QRS segment. In some people, the P wave on the ECG may be absent, completely merging with the QRS, which indicates the pathology of the atria and ventricles, which the impulse reaches at the same time.

The ventricular rhythm is shown on the electrocardiogram as a deformed and extended QRS. In this case, the connection between P and QRS is not visible. There are large distances between the R waves.

cardiac conduction

ECG determines cardiac conduction. The P wave determines the atrial impulse, normally this indicator should be 0.1 s. The P-QRS interval displays the overall atrial conduction velocity. The norm of this indicator should be in the range of 0.12 to 0.2 s.

The QRS segment shows conduction through the ventricles, the limit is considered to be the norm from 0.08 to 0.09 s. With an increase in intervals, cardiac conduction slows down.

What the ECG shows, patients do not need to know. This should be dealt with by a specialist. Only a doctor can correctly decipher the cardiogram and make the correct diagnosis, taking into account the degree of deformation of each individual tooth, segment.

An electrocardiogram is the first indicator of the state of the heart. It reflects all the problems of the human cardiovascular system, makes it possible to identify ailments at an early stage in order to take the necessary treatment. But in order to correctly diagnose, the cardiogram must be correctly interpreted.

What is a cardiogram

Deciphering an ECG requires a clear understanding of what this test is all about. 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 0.04 seconds, respectively, large blocks of 5 mm are equal to 0.2 seconds. The black marks at the top represent intervals of three seconds. A vertical line consisting of two blocks is equal to one millivolt - this is a unit of electrical voltage, a thousandth of a volt. To understand what is at stake, 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 - 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. The electrodes on the body are placed accordingly.

The propagation of an impulse through the heart on the cardiogram is displayed by intervals, segments and teeth. The latter are denoted in Latin letters: P, Q, R, S, T, U. The R wave is always negative, it displays indicators for 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 diagnosing does not play a special role. The normal interpretation of the ECG provides that all indicators must be calculated to a hundredth of a second, otherwise they can be misinterpreted.

What indicators are considered optimal

To effectively decipher the ECG, you need to study the indicators of the norm. First of all, you should pay attention to the 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 display of the ventricular excitation vector from an impulse, it is considered 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 the normal position, the angle value is 50-70 degrees. It is worth paying attention: the R wave should be higher than the S. The intervals of the teeth show how the electrical impulse passes between the compartments of the heart. Each of them has specific indicators of the norm.

1. The width of the Q-R-S wave group under normal conditions is 60-100 ms.
2. The Q-T wave group displays the duration of the 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-tooth must not exceed a height of 20 mm.
5. The norm for the T wave is that in leads I and II it should go up, and in lead aVR it should have a negative indicator.

Identification of abnormalities and diseases

If you deal with the indicators of the norm, when deciphering the ECG, any pathology can be detected independently. Let's start with heart rate. If the electrical excitation does not start from the sinus node, this is an indicator of an arrhythmia. Depending on the branch of the heart in which depolarization begins, tachycardia (acceleration of the rhythm) or bradycardia (deceleration) 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 disease. When Q values ​​do not meet the norm, this signals myocardial pathologies.


2. If the R wave is not displayed in all leads, this indicates that ventricular hypertrophy is possible.
3. Deviations in the ST segment indicate myocardial ischemia.
4. A T wave that is out of range may indicate hypokalemia or hyperkalemia.
5. The expansion of the P wave, especially twice, indicates an 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 indicates 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 disease. The doctor should be concerned if, within a short time, the electrical axis suddenly changed position. The peculiarity of the EOS is that its performance may depend on various factors. For example, the vertical position is often found in thin people, and the horizontal position is common in full people.

A cardiogram can indicate a number of diseases. But do not rush to diagnose yourself. It is very difficult to interpret the ECG for beginners, 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.

medso-sud.ru

Basic Rules

When examining the results of the examination of the patient, 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.

ECG analysis

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

To date, all these indicators are investigated 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 easy to identify 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 the ECG. To do this, you need to know the speed at which the ECG was recorded (usually 25, 50 or 100mm / s), as well as the distance between the highest teeth (from one peak to another).

By multiplying the recording time of one mm by length of segment R-R you can get your heart rate. Normally, its performance ranges from 60 to 80 beats per minute.

Source of excitation

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

In some cases, other nodes (atrial, ventricular, atrioventricular) can take on the role of the pacemaker. 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 momentum transfer. Normally, impulses are transmitted sequentially from one pacemaker to another, without changing the order.

Electric axle

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

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

Teeth, segments and intervals

Teeth - ECG sections 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 sections of the ECG lying on the isoline.

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

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

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

Norm in men and women

The decoding of the ECG of the heart and the norms of indicators in adults are presented in this table:

Healthy Childhood Outcomes

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

Dangerous diagnoses

What dangerous conditions can be determined by the ECG readings during decoding?

Extrasystole

This phenomenon characterized by irregular heartbeat. A person feels a temporary increase in the frequency of contractions, followed by a pause. It is associated with the activation of other pacemakers, sending along with the sinus node an additional burst of impulses, which leads to an extraordinary contraction.

Arrhythmia

Characterized change in the frequency of sinus rhythm when pulses arrive at different frequencies. Only 30% of these arrhythmias require treatment, because can lead to more serious illnesses.

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

Bradycardia

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

Tachycardia

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

Conduction disorder

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 time of day. Usually, an ECG is recommended to be done in the morning or afternoon, when the body has not yet had time to be influenced by stress factors.
• Loads. It is very important that the patient is calm while recording the ECG. The release of hormones can increase heart rate and distort performance. In addition, before the examination, it is also not recommended to engage in heavy physical labor.
• meal. Digestive processes affect blood circulation, and alcohol, tobacco and caffeine can affect heart rate and pressure.
• electrodes. Improper overlap or accidental shifting can seriously change the performance. Therefore, it is important not to move during the recording and 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 other devices can interfere with the operation of the electrocardiograph.

Additional examination methods

Halter

Method long-term study of the work of the heart, made possible by a portable compact tape recorder that is capable of recording results on magnetic tape. The method is especially good when it is necessary to investigate recurrent pathologies, their frequency and time of occurrence.

Treadmill

Unlike a conventional ECG recorded at rest, this method is based on the analysis of the results after exercise. 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 had 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, the risks of developing endocarditis and rheumatic heart disease.

A standard ECG is a graphic representation of the work of all parts of the heart. Its accuracy can be affected by many factors, so doctor's advice should be followed.

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

Finally, we suggest watching a video course on decoding “ECG for everyone”:

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What is an ECG, how is the procedure

The principle of obtaining an ECG is very simple. We are talking about the fact that sensors are attached to the skin of the patient, which record the electrical impulses that accompany the beating of the heart. Recording is done on a sheet of paper. A competent doctor can tell a lot about the patient's health from this diagram.

It depicts cyclical changes in the corresponding electrical impulses. It is important to note that this diagnostic method is not absolutely accurate and exhaustive. It can be considered, 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 it right? Do I need to be a specialist in order to carry out this procedure, or if all the necessary rules are carefully followed, even a non-specialist can carry out the procedure? Let's try to answer these questions.

Interestingly, the electrocardiogram is used not only in the treatment of cardiac patients, but also in a number of other cases:

• This takes place not only during various medical examinations, but also for the diagnosis of those diseases that are not directly related to the heart, but can create complications in it.
• Also, when using those medicines that have a strong effect on the body, the state of health of the cardiovascular system is often checked in this way in order to prevent possible consequences of taking such medicines.
  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 must 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 should lie on his back.
3. During work, he should have even breathing.
4. You also need to take into account the time of eating. Everything should be done either on an empty stomach or not earlier than two hours after the last meal. This reception should not be plentiful.
5. Of course, on the day of the procedure, it is not allowed to take any sedative or tonic drugs. Also, do not drink coffee or tea or other similar drinks. If the patient smokes, then he should refrain from this habit for at least an hour before the procedure.

Diagnostic technique including
It includes the attachment of four electrodes to the hands and ankles and the installation of six suction cups on the patient's chest.

Do it in the following order. Each electrode has a specific color. Put a damp cloth under them. This is done both to increase conductivity and to improve the 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 display several types of teeth that have a different shape.

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 do a cardiogram?

There are several main options:

• This should be done if you clearly feel discomfort in the chest.
• With shortness of breath, although it may look familiar, it makes sense to see a doctor for an ECG.
• If you are overweight, then you are undoubtedly at risk for heart disease. It is recommended to do an electrocardiogram regularly.
• The presence of chronic and severe stress in your life is a danger not only to your heart, but also to other systems of the human body. An ECG in such a case is a matter of vital importance.
• There is such a chronic disease as tachycardia. If you suffer from it, then the ECG should be done regularly.
• Hypertension is considered by many as a possible step towards a heart attack. If at this stage you regularly diagnose using an ECG, then your chances of recovering will increase dramatically.
• Before performing a surgical operation, it is important for the doctor to make sure. That your heart can handle 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 the ECG show

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

1. First of all, she will tell in detail about all the features of the rhythm of the heartbeat. 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 the ECG is able to 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 to identify those who are not yet sick, but have a tendency to do so.
3. There is an ECG under stress. This is useful in cases where a relatively healthy person wants to assess the health of their heart.

Principles for decoding indicators

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

Each disease corresponds to specific signs on the ECG graphs. If they are determined, then this makes it possible to make the correct diagnosis to the patient. The norm and violations in the interpretation of 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 teeth

There are five different types of waveforms on an ECG. They are designated in Latin letters: S, P, T, Q And R. Each of them characterizes the work of one of the sections of the heart.

Different 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.

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

In more detail, the elements of the ECG are shown 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 cuts per second.

How the 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 an elongation 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 that, an indicator such as the electrical axis of the heart (EOS) is determined. This is done using a calculation based on the height of the different types of waves on the electrocardiogram.
3. After that, the complex is considered. We are talking about a tooth of the R type and its nearest sections of the graph on both sides.
4. Next is the interval. It is believed that for a normal heart, it should be in the midline.
5. After that, based on the studied data, a final cardiological conclusion is given.

• P - normally should be positive, shows the presence of bioelectricity in the atria;
• The Q wave is normally negative, it 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 electricity in the ventricles, normally such a tooth will be lower than the R wave;
• T - must be positive, here we are talking about the recovery 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 violations in the work of the heart.
• QT - the interval is normal for an adult is 390-450 milliseconds.
• The width of the QRS interval should be approximately 120 milliseconds.

Possible errors in the result

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

Pathologies in the interpretation of the ECG 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, then 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 about the same as in Moscow. ECG price with decoding is approximately 1500 rubles for this procedure.

There is also a service to call such a specialist at home. In Moscow, this service can be provided for 1500 rubles, in Khabarovsk - for 900 rubles, and in Saratov it can be done for 750 rubles.

Conclusion

An ECG is an important means of diagnosing your cardiovascular system. She has a lot to say about her. It makes sense to regularly, at least once every two years, seek an ECG from a doctor.

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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, as 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 back. To record an ECG in 12 leads, special electrodes are attached to the patient's body in specific places and in a certain sequence.

How to decipher the cardiogram of the heart: 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. It determines whether the heart beats rhythmically, that is, whether the rhythm is correct. To do this, he measures the intervals between the R waves, they should be the same everywhere, if not, this is already the wrong rhythm.
2. Calculates the rate at which the heart beats (HR). This is easy to do, knowing the ECG recording speed and counting the number of millimeter cells between adjacent R waves. Normally, the heart rate should not go beyond 60-90 beats. in a minute.
3. According to specific features (mainly by 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. Assesses the conduction of the heart by the duration of the teeth and segments. For each of them there are indicators of the norm.
5. Determines the electrical axis of the heart (EOS). For very thin people, a more vertical position of the EOS is characteristic, for full people it is more horizontal. 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 work of the doctor.
7. Gives a conclusion. It necessarily indicates the correctness of the rhythm, the source of excitation, heart rate, characterizes the EOS, and also highlights specific pathological syndromes (rhythm disturbance, conduction disturbance, the presence of overload of individual parts of the heart and myocardial damage), if any.

Examples of electrocardiographic findings

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

Also, for some people, sinus tachycardia (acceleration of heart rate) or bradycardia (slow heart rate) can be considered a normal option. 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 correction of the patient's nutrition, they mostly always disappear.

In addition, in conclusion, we can talk about a non-specific change in the ST-T interval. This means that the changes are not indicative and it is impossible to determine their cause only by the ECG. Another fairly common condition that can be diagnosed by 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 imbalances and other causes that the doctor will subsequently look for.

Prognostically unfavorable conclusions are considered, in which there is data on the presence of myocardial ischemia, hypertrophy of the heart, rhythm and conduction disturbances.

Deciphering the ECG in children

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

Also, sinus or respiratory arrhythmia (increased heart rate on inspiration and decrease on expiration) can be recorded in babies without any pathology. In addition, the characteristics of some teeth 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 leg of the bundle of His. All these features are taken into account by pediatric cardiologists when they make a conclusion on the ECG.

Features of the ECG during pregnancy

The body of a pregnant woman goes through various processes of adaptation to a new situation. Certain changes also occur with the cardiovascular system, so the ECG of future 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 have a slight sinus tachycardia and signs of overload of individual parts of the heart. These changes are associated with an increase in blood volume in the body and usually disappear after childbirth. However, their discovery cannot be left without detailed consideration and a more in-depth examination of the woman.

Deciphering the ECG, the norm of indicators

Deciphering the ECG is the business of a knowledgeable doctor. With this method of functional diagnostics, the following is evaluated:

• heart rhythm - the state of the generators of electrical impulses and the state of the heart system that conducts these impulses
• the state of the heart muscle itself (myocardium). the presence or absence of its 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 bring even the most balanced, but ignorant person to a panic disorder. Indeed, often the patient does not know for certain how dangerous for life and health what is written on the back of the ECG film by the hand of a functional diagnostician, and there are still a few days before an appointment with a therapist or cardiologist.

To reduce the intensity of passions, we immediately warn readers that with no serious diagnosis (myocardial infarction, acute rhythm disturbances), the functional diagnostician of the patient will not let the patient out of the office, but at least send him for a consultation with a specialist colleague right there. About the rest of the "secrets of the Open" in this article. In all unclear cases of pathological changes on the ECG, ECG control, daily monitoring (Holter), ECHO cardioscopy (ultrasound of the heart) and stress tests (treadmill, bicycle ergometry) are prescribed.

Numbers and Latin letters in ECG decoding

PQ- (0.12-0.2 s) - time of atrioventricular conduction. 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. Can talk about 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 apexes of the ventricular complexes reflects the regularity of heart contractions and makes it possible to calculate the heart rate.

The decoding of the ECG in children is shown in Fig. 3

Options for describing the heart rate

Sinus rhythm

This is the most common inscription found on the ECG. And, if nothing else is added and the frequency (HR) is indicated from 60 to 90 beats per minute (for example, heart rate 68`) - this is the most successful 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, it can be atrial, atrioventricular or ventricular, indicating that the rhythm is set by the cells in these parts of the heart and is considered pathological.

This is a variant of the norm in young people and children. This is a rhythm in which impulses exit the sinus node, but the intervals between heartbeats are different. This may be due to physiological changes (respiratory arrhythmia, when heart contractions slow down on exhalation). Approximately 30% of sinus arrhythmias require observation by a cardiologist, as they are threatened by the development of 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 people with a 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. Also, bradycardia is often seen in professional athletes. Pathological bradycardia may indicate sick sinus syndrome. At the same time, 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 disruptions in the supply of oxygen to tissues and manifests itself, for example, by fainting, an operation is indicated to install a heart 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 in a short period of time after the cessation of the load. With pathological tachycardia, palpitations disturb the patient at rest. Its causes are temperature rises, infections, blood loss, dehydration, thyrotoxicosis, anemia, cardiomyopathy. Treat the underlying disease. Sinus tachycardia is stopped only with a heart attack or acute coronary syndrome.

Extrasystole

These are rhythm disturbances, in which foci outside the sinus rhythm give extraordinary heart contractions, after which there is a pause doubled in length, called a compensatory one. In general, heartbeats are perceived by the patient as uneven, rapid or slow, sometimes chaotic. Most of all, failures in the heart rhythm are disturbing. There may be discomfort in the chest in the form of jolts, tingling, feelings of fear and emptiness in the abdomen.

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 disruptions), organic (with IHD, heart defects, myocardial dystrophy or cardiopathy, myocarditis). They can also lead to intoxication and heart surgery. Depending on the place of occurrence, extrasystoles are divided into atrial, ventricular and antrioventricular (arising in a node on 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 the normal blood supply.
• Paired extrasystoles of two accompany a certain number of normal contractions. Such a rhythm disturbance often indicates pathology and requires additional examination (Holter monitoring).
• Allorhythmias are more complex types of extrasystoles. If every second contraction is an extrasystole, it is bigymenia, if every third is trigynemia, and every fourth is quadrihymenia.

It is customary to divide ventricular extrasystoles into five classes (according to Laun). They are evaluated during daily ECG monitoring, since the indicators of a conventional 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 grades 3 and 4 do not always require medical treatment. In general, if there are less than 200 ventricular extrasystoles per day, they should be classified as functional and not worry about them. With more frequent, ECHO of the COP is indicated, sometimes - MRI of the heart. They do not treat extrasystole, but the disease that leads to it.

Paroxysmal tachycardia

In general, paroxysm is an attack. Paroxysmal acceleration of the rhythm can last from several minutes to several days. In this case, the intervals between heartbeats 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. The basis of this pathology is the abnormal circulation of an electrical impulse in the conduction system of the heart. Such a pathology is subject to treatment. From home remedies to eliminate an attack:

• breath holding
• increased forced cough
• face immersion in cold water

WPW syndrome

Wolff-Parkinson-White syndrome is a type of paroxysmal supraventricular tachycardia. Named after the names of the authors who described it. At the heart of the appearance of tachycardia is the presence between the atria and ventricles of an additional nerve bundle, 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 (with ineffectiveness or intolerance of antiarrhythmic tablets, with episodes of atrial fibrillation, with concomitant heart defects).

CLC - Syndrome (Clerk-Levy-Christesco)

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

Atrial fibrillation

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

Atrial fibrillation

Atrial fibrillation

When the heart flickers, it contracts completely irregularly (intervals between contractions of very different durations). This is due to the fact that the rhythm is not set by the sinus node, but by other atrial cells.

It turns out a frequency of 350 to 700 beats per minute. There is simply no full-fledged atrial contraction; the contracting muscle fibers do not provide effective filling of the ventricles with blood.

As a result, the release of blood by the heart worsens 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 either be 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 heartbeat.
• It develops as a series of absolutely non-rhythmic 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 arousal.
• Sometimes there is a loss of consciousness.
• The attack ends with the normalization of the rhythm and the urge to urinate, in which a large amount of urine leaves.

To stop the attack, they use reflex methods, drugs in the form of tablets or injections, or resort to cardioversion (stimulation of 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 of patients and are felt only with 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 in '.
• Atrial fibrillation, normosystolic variant, heart rate 64 in '.

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

atrial flutter

These are frequent (more than 200 per minute) regular atrial contractions and the same regular, but more rare ventricular contractions. In general, flutter is more common in the acute form and is better tolerated than flicker, since circulatory disorders are less pronounced. Trembling develops when:

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

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

Conduction disorders

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

Sinoatrial blockade

When the exit of the impulse from the sinus node is difficult. In fact, this leads to a syndrome of weakness of the sinus node, a decrease in 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 the Samoilov-Wenckebach syndrome.

Atrioventricular block (AV block)

This is a delay in excitation in the atrioventricular node of more 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.

• At the first delay allows each atrial contraction to maintain an adequate number of ventricular contractions.
• The second degree leaves part of the atrial contractions without ventricular contractions. It is described in terms of PQ prolongation and ventricular beat prolapse as Mobitz 1, 2, or 3.
• The third degree is also called a complete transverse block. The atria and ventricles begin to contract without interrelation.

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 be detected only with an ECG, then the second is already characterized by sensations of periodic cardiac arrest, weakness, fatigue. With complete blockades, cerebral symptoms (dizziness, flies in the eyes) are added to the manifestations. Morgagni-Adams-Stokes attacks may develop (when the ventricles escape from all pacemakers) with loss of consciousness and even convulsions.

Conduction disturbance within the ventricles

In the ventricles to the muscle cells, the electrical signal propagates through such elements of the conduction system as the trunk of the bundle of His, its legs (left and right) and the 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 covered by excitation at the same time, one of the ventricles is delayed, since the signal to it goes around the blocked area.

In addition to the place of origin, a complete or incomplete blockade is distinguished, as well as permanent and non-permanent. The causes of intraventricular blockades are similar to other conduction disorders (IHD, myo- and endocarditis, cardiomyopathies, heart defects, arterial hypertension, fibrosis, heart tumors). Also, the intake of antiarthmic drugs, an increase in potassium in the blood plasma, acidosis, and oxygen starvation also affect.

• The most common is the blockade of the anteroposterior branch of the left leg of the bundle of His (BPVLNPG).
• In second place is the blockade of the right leg (RBNB). This blockade is usually not accompanied by heart disease.
• Blockade of the left leg of the His bundle is more typical for myocardial lesions. At the same time, complete blockade (PBBBB) is worse than incomplete blockade (NBLBBB). It sometimes has to be distinguished from the WPW syndrome.
• The blockade of the posterior inferior branch of the left leg of the bundle of His can be in persons with a narrow and elongated or deformed chest. Of the pathological conditions, it is more characteristic of right ventricular overload (with pulmonary embolism or heart defects).

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

• Bailey's syndrome - two-beam blockade (of the right leg and posterior branch of the left leg of the bundle of His).

Myocardial hypertrophy

With chronic overloads (pressure, volume), the heart muscle in some areas begins to thicken, and the heart chambers 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 in normal athletes, obese patients and people engaged in heavy physical labor, there may be signs of LVH.
• Right ventricular hypertrophy is an undoubted sign of increased pressure in the pulmonary circulation system. Chronic cor pulmonale, obstructive pulmonary disease, cardiac defects (pulmonary stenosis, Fallot's tetralogy, ventricular septal defect) lead to HPZh.
• Left atrial hypertrophy (HLH) - 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 pulmonary embolism.
• Indirect signs of ventricular hypertrophy are the 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 LVH.
• 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

Syndrome of early repolarization of the ventricles

Most often, it is a variant of the norm, especially for athletes and people with congenitally 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 it does not give a clinic and most often remains without consequences.

Moderate or severe diffuse changes in the myocardium

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

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

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

This describes the reversible changes associated with oxygen starvation of the myocardium (ischemia). It 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, rapid troponin tests for myocardial damage or coronary angiography should be performed. Depending on the variant of coronary heart disease, anti-ischemic treatment is selected.

Developed heart attack

It is usually described as:

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

All the variety of syndromes and specific ECG changes, 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 a ready-made conclusion of a functional diagnostician. It is much more reasonable, having an 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 the ECG of the heart?

An electrocardiographic study is the simplest, but very informative method for studying the work 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. Deciphering 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 tells 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 the cardiogram of all 12 leads, electrodes are attached to the patient's body. The specialist does this sequentially, installing them in specific places.

Decryption principles

Each curve on the cardiogram graph has its own elements:

• Teeth, which are bulges directed down or up. All of them are denoted by Latin capital letters. "P" shows the work of the heart atria. "T" is the restorative capacity of the myocardium.
• Segments are the distance between several ascending or descending teeth in the neighborhood. Doctors are especially interested in 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 ECG element shows a certain process that occurs directly in the heart. According to their width, height and other parameters, the doctor has the ability to correctly decipher the data received.

How are the results analyzed?

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

1. The correct rhythm is determined by the intervals between the "R"-teeth. They must be equal. Otherwise, it can be concluded that the heart rhythm is incorrect.
2. With the help of an ECG, you can determine the 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 features. This will be told, among other things, by the evaluation of the parameters of the “P” wave. The norm implies that the source is the sinus node. Therefore, a healthy person always has a sinus rhythm. If there is a ventricular, atrial or any other rhythm, then this indicates the presence of pathology.
4. The specialist evaluates the conduction of the heart. This happens according to the duration of each segment and tooth.
5. The electrical axis of the heart, if it shifts to the left or right sharply enough, may also indicate problems with the cardiovascular system.
6. Each tooth, interval and segment is analyzed individually and in detail. Modern ECG devices immediately automatically issue indicators of all measurements. This greatly simplifies the work of the doctor.
7. Finally, the specialist makes a conclusion. It indicates the decoding of the cardiogram. If any pathological syndromes were found, they must be indicated there.

Normal indicators of adults

The norm of all indicators of the cardiogram is determined by analyzing the position of the teeth. But the rhythm of the heart 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, it will no longer be the norm, which should be within 60-80 pulsations per minute. If sinus rhythm is more frequent, then the patient has tachycardia. On the contrary, a slow sinus rhythm indicates a disease called bradycardia.

The P-QRS-T intervals will tell you about the passage of the impulse directly through all the cardiac departments. 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, one 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 Q-T interval. The norm is 390-450 ms. If it is somewhat longer, a diagnosis can be made: rheumatism, ischemia, atherosclerosis. If the interval is shortened, we can talk about hypercalcemia.

What do teeth mean?

Without fail, when deciphering the ECG, it is necessary to monitor the height of all teeth. It can indicate the presence of serious pathologies of the heart:

• 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 pathology of the myocardium;
• The S wave is an indicator of the excitation of those partitions that are in the basal layers of the ventricles. The norm in this case is 20 mm in height. If there are deviations, then this indicates coronary disease.
• The R wave in the ECG tells about the activity of the walls of all the ventricles of the heart. It is fixed in all ECG curves. If there is no activity somewhere, then it makes sense to suspect ventricular hypertrophy.
• The T wave appears in the I and II lines, as directed upwards. 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 possibility 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 babies under 3 years old is about 110 pulsations per minute, and at the age of 3-5 years - 100 beats. This indicator in adolescents is already lower - 60-90 pulsations.
2. The norm of QRS readings is 0.6-0.1 s.
3. The P wave should normally not be higher than 0.1 s.
4. The electrical axis of the heart in children should remain unchanged.
5. The rhythm is only sinus.
6. On the ECG, the Q-T interval e can exceed 0.4 s, and P-Q should be 0.2 s.

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

Why are the scores different?

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

1. Distortions in recording an ECG may be due to technical problems. For example, with incorrect gluing of results. And many Roman numerals look the same both upside down and 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 hearty breakfast, it is even advisable to completely refuse it. You will have to stop drinking liquids, including coffee and tea. After all, they stimulate the heart rate. As a result, the results are skewed. It is best to take a shower beforehand, but you do not need to apply any body products. Finally, during the procedure you need to relax as much as possible.
3. The incorrect position of the electrodes cannot be ruled out.

It is best to check your heart on an electrocardiograph. He will help to carry out the procedure as accurately and accurately as possible. And in order to confirm the diagnosis indicated by the results of the ECG, the doctor will always prescribe additional studies.