How to determine sinus rhythm. What is sinus rhythm? The norm for this indicator. SR abnormalities on ECG

An electrocardiograph (ECG) is a device for assessing electrical activity heart muscle. In cardiology, it is most in demand, as it allows you to detect any changes in the heartbeat, organic lesions and electrolyte imbalances. When interpreting the cardiogram, sinus rhythm is detected in the absence of pathological abnormalities. Evaluates final results experienced specialist. To the common man Latin letters and curved lines will not say anything. Generally accepted standards and definitions will help you figure out the decoding yourself.

The sinus rhythm detected on the electrocardiogram is displayed by identical teeth at equal intervals of time and indicates the correct functioning of the heart. The source of impulses is set by the natural pacemaker, the sinus (sinusoidal) node. It is localized in the angle of the right atrium and serves to generate signals that cause sections of the heart muscle to contract one by one.

Feature sinus node is an abundant blood supply. The number of impulses it sends is influenced by the departments (sympathetic, parasympathetic) of the autonomic nervous system. If there is a malfunction in their balance, the rhythm is disturbed, which is manifested by an increase in heart rate (tachycardia) or slowdown (bradycardia).

Normally, the number of pulses generated should not exceed 60-80 per minute.

Maintaining sinus rhythm is important for stable circulation. Under the influence of external and internal factors Impairment of regulation or conduction of impulses may occur, which will lead to disruptions in hemodynamics and dysfunction internal organs. Against this background, the development of signal blockade or weakening of the sinusoidal node is possible. On the electrocardiogram, the resulting disorder is displayed as the presence of a focus of replacement (ectopic) impulses in a certain part of the heart muscle:

• atrioventricular node;
• atria;
• ventricles.

When the signal source is located anywhere other than the sinus node, we are talking about heart pathology. The patient will have to undergo a series of examinations ( daily monitoring ECG, load tests, ultrasonography) to reveal causative factor violations. Treatment will be aimed at eliminating it and restoring sinus rhythm.

Decoding the cardiogram of the heart: sinus rhythm

Panic when a “sinus rhythm” recording is detected is typical for people unfamiliar with medical terms. Usually the cardiologist prescribes a series of examinations, so you will be able to see him again only after receiving all the results. The patient can only wait patiently and familiarize himself with publicly available sources of information.

In fact, sinus rhythm is the generally accepted norm, therefore, there is no point in worrying. Deviations are possible only in heart rate (HR). It is affected by various physiological factors, influence vagus nerve and vegetative failures. The number of heart beats per minute may become higher or lower than normal for age, despite sending signals from the natural pacemaker.

A diagnosis of “tachycardia” or “bradycardia” of sinus type is made only after a comprehensive assessment of all the nuances. The doctor will pay attention to the patient’s condition and ask about the actions performed immediately before the study. If the decrease or increase in heart rate is minor and is associated with exposure external factors, then the procedure will be repeated a little later or on another day.

Identification of the natural pacemaker during electrocardiography occurs according to generally accepted criteria:

• the presence of a positive P wave in the second lead;
• there is an equal interval between the P and Q waves, not exceeding 0.2 seconds;
• negative P wave in lead aVR.

If the transcript indicates that the patient is in sinus rhythm and normal position electrical axis hearts (EOS), then they are afraid of nothing. The rhythm is set by its natural driver, that is, it comes from the sinus node into the atria, and then into the atrioventricular node and ventricles, causing alternate contractions.

Acceptable standards

Whether the cardiogram readings are normal can be determined by the position of the teeth. Heart rhythm is assessed by the interval between teeth R-R. They are the highest and should normally be the same. A slight deviation is acceptable, but not more than 10%. Otherwise, we are talking about a slowdown or increase in heart rate.

The following criteria are typical for a healthy adult:

• P-Q interval varies within 0.12-0.2 seconds;
• Heart rate is 60-80 beats per minute;
• the distance between the Q and S teeth remains in the range from 0.06 to 0.1 sec;
• the P wave is 0.1 sec;
• The Q-T interval varies from 0.4 to 0.45 seconds.

In children, the indicators are slightly different from adults, which is due to the characteristics of the child’s body:

• QRS interval does not exceed 0.1 second;
• Heart rate varies depending on age;
• the distance between the Q and T teeth is no more than 0.4 seconds;
• P-Q interval 0.2 sec.
• the P wave does not exceed 0.1 sec.

In adults, as in children, in the absence of pathologies, there should be a normal position of the electrical axis of the heart and sinus rhythm. Acquainted with permissible frequency Abbreviations by age can be found in the table:

Reasons for deviation from the norm

Heart rate varies depending on the time of day, psycho-emotional state and other external and internal factors. To obtain reliable data, you will need to take into account many nuances:

Equally important is careful preparation for the procedure:

If you were unable to follow all the rules, then upon arrival at the diagnostic room you should tell the specialist about it. He will take into account this nuance and, if necessary, schedule an examination for another day.

General list of factors that can affect frequency and rhythm heart rate, as follows:

• mental disorders;
• overwork (psycho-emotional, physical);
• developmental defects (congenital, acquired);
• reception medicines with antiarrhythmic effect;
• disruption valve apparatus(insufficiency, prolapse);
• dysfunction of the endocrine glands;
• advanced stage of heart failure;
• pathological changes in the myocardium;
• inflammatory heart diseases.

About taking medications, especially to stabilize blood pressure (“Mexarithma”, “Amidarone”) and improve metabolic processes(“Metonate”, “Adenosine”), must be reported before the procedure. Many heart medications can slightly distort the results.

Features of deciphering an electrocardiogram

Based on the electrocardiogram, the cardiologist will be able to assess the electrical potential of the heart muscle during systole (contraction) and diastole (relaxation). Displays data in 12 curves. Each of them demonstrates the passage of an impulse through a specific part of the heart. Waveforms are recorded on 12 leads:

• 6 leads on the arms and legs designed to assess vibrations in the frontal plane.
• 6 leads in the chest area for recording potentials in the horizontal plane.

Each curve has its own elements:

• Teeth by appearance resemble convexities directed up and down. They are designated by Latin letters.
• Segments are the distance between several teeth located nearby.
• An interval is a gap consisting of several teeth or segments.

General principles of decoding

Electrocardiogram evaluation is complex process. The doctor carries it out step by step so as not to miss the slightest changes:

To better understand the information, it is advisable to familiarize yourself with various options expert opinions:

• A healthy person is characterized by sinus rhythm, 60-80 heartbeats per minute, EOS in a normal position and the absence of pathologies.
• With an increased or decreased heart rate, sinus tachycardia or bradycardia is indicated in conclusion. The patient will be advised to undergo several more examinations or repeat the procedure on another day if the result was influenced by external factors.
• In elderly patients and people who do not healthy image life, often reveal pathological changes in the myocardium of a diffuse or metabolic nature.
• A record of the presence of nonspecific changes in the ST-T interval indicates the need for additional examinations. To figure out the real reason only with the help of electrocardiography in in this case no possibility.
• The detected repolarization disorder indicates incomplete recovery of the ventricles after contraction. Usually affect the process various pathologies and hormonal imbalances. To detect them, several more examinations will be required.

For the most part, the conclusions are positive. Changes can be overcome with lifestyle changes and medications. An unfavorable prognosis is usually when coronary artery disease, proliferation (hypertrophy) of the chambers of the heart muscle, arrhythmia and failures in the conduction of impulses are detected.

Causes of deviations in sinus rhythm

Abnormal sinus rhythm appears under the influence of pathologies or physiological factors. The forms of failure differ depending on the frequency and rhythm of contractions:

Despite the correct source of signals, the problem that has arisen must be dealt with. If no action is taken, a more severe form of arrhythmia may develop and manifest itself dangerous symptoms disruptions in hemodynamics.

Sinus tachycardia

The sinus form of tachycardia can be pathological or physiological. In the first case, it occurs due to other diseases, and in the second, after stress and overwork. The electrocardiogram usually reveals an increased frequency of contractions from 100 to 220 per minute and a short P-P interval.

For an attack sinus tachycardia The following symptoms are typical:

• feeling of heartbeat;
• lack of air;
• general weakness;
• dizziness;
• sleep disturbance;
• chest pain;
• noise in ears.

Attacks of sinus bradycardia, like tachycardia, occur as a symptom of other diseases or as a reaction to physiological factors. They are characterized by a decrease in heart rate to 60 beats per minute or less. The electrocardiogram shows a noticeable increase in the distance between the P-P waves.

In addition to a slow heartbeat, during an attack of bradycardia the following symptoms appear:

• dizziness;
• fainting state;
• pain in the heart area;
• pale skin;
• tinnitus;
• fast fatiguability.

Sinus arrhythmia

The sinus variety of arrhythmia usually results in an irregular rhythm. Heart rate may increase or decrease sharply due to various stimuli. Length RR interval is changing.

An attack of sinus arrhythmia is characterized by the following symptoms:

Features of ECG interpretation in children

Electrocardiography is performed in children in the same way as in adults. Problems can only arise with hyperactive kids. They must first be reassured and the importance of the procedure explained. The results obtained differ only in heart rate. During active growth, the heart has to work harder to supply all tissues of the body in full. As the child develops, the heartbeat gradually returns to normal.

Signs of sinus rhythm in children are similar to adults. The increase in heart rate must be within the acceptable range age limit. If a focus of ectopic impulses is detected, then we can talk about congenital defect heart development. It can only be completely removed through surgery.

Cases of mild sinus arrhythmia are most often associated with respiratory system. During inhalation, the heart rate increases and stabilizes as you exhale. Such failures are typical for children and go away over time. At conducting an ECG respiratory arrhythmia must be taken into account, since a cold couch, fear and other factors provoke its aggravation.

The sinus form of arrhythmia can be provoked by more dangerous causes:

Due to the voiced pathological processes increases the likelihood of developing complications that can lead to fatal outcome and disability. Among less serious reasons can be distinguished active growth, rickets and vegetative-vascular dystonia. In most cases, they go away on their own. It is enough for parents to give their child vitamin complexes and diversify his diet.

Decoding the electrocardiogram during pregnancy

During pregnancy, significant changes occur in a woman’s body that affect the results of electrocardiography:

• An increase in circulating blood volume contributes to the development of tachycardia and the manifestation of signs of overload in certain parts of the heart muscle.
• The growing uterus provokes displacement of internal organs, which is manifested by a change in the location of the electrical axis of the heart.
• Hormonal surges affect all systems in the body, especially the nervous and cardiovascular systems. A woman experiences attacks of tachycardia after any physical exertion. Heart rate usually increases by no more than 10-20 beats per minute from normal.

The changes that occur go away on their own after the birth of the child, but in some cases they develop into a full-fledged pathological process. To prevent it, it is necessary to be observed by a doctor throughout the entire pregnancy.

The meaning of letters and numbers on an electrocardiogram

Understand what it's about we're talking about in an electrocardiogram, the definitions of the Latin letters that name the teeth will help:

• The PQ interval shows how long it takes for an electrical impulse to travel through the heart muscle (from the atria to the ventricles). With absence irritating factors length does not exceed 0.2 sec. Based on this indicator, the doctor will evaluate general state conductor system. If there is a lengthening of the distance between the P and Q waves, then the problem may be the development of heart block.
• Along the space between the teeth R-R doctor determines the regularity of contractions and counts them.
• The QRS complex helps you see how the signal is conducted through the ventricles.
• The segment between the S and T waves shows the moment the excitation wave passes through the ventricles. Its permissible length is 0.1-0.2 seconds. The segment is located on an isoline. If it is slightly displaced, then certain pathological processes can be suspected:
  • higher by 1 mm or more – myocardial infarction;
  • lower by 0.5 or more – ischemic disease;
  • saddle-shaped segment – ​​pericarditis.

It will not be easy for an ordinary person to decipher an electrocardiogram. First, you will have to familiarize yourself with the definition of the Latin symbols that indicate the teeth, and the features of the intervals between them. Then you need to study the types of heart rhythm and generally accepted heart rate norms. Finally, it is advisable to review the options for expert opinions and general principles transcripts. Based on the information studied, even a person far from medicine will be able to understand the cardiogram.

• Basic ECG parameters
• Sinus rhythm abnormalities on ECG
• Classification of arrhythmia
• Clinical picture of sinus rhythm disorders

Also in his conclusion, the cardiologist can indicate the stability or instability of the heart rhythm. This indicator is also determined by the length of the intercomplex intervals. In this case, there are two extreme variants of pathology: and.

In the first case, there is too frequent (more than 100 times per minute) generation of contractions by the sinoatrial node. In the case of bradycardia, a small number of heart contractions per unit of time is observed. Clinicians consider the minimum limit of normal, taking into account physiological characteristics, value 50 beats per minute.

At the same time, both variants of the pathology carry quite significant grounds for immediate rhythm correction, since they equally have a detrimental effect on the functioning of the heart.

If we talk about instability of sinus rhythm, or, then this problem is highlighted by cardiologists in separate group heart diseases.

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Classification of arrhythmia

They involve the allocation large quantity various types of arrhythmias.

The extreme variants of development are complete dysfunction of the sinoatrial node with the formation of atrial fibrillation and flutter.

In such cases, the heart rate exceeds 250-500 beats per minute, the waves on the ECG are practically not tracked, and the formation of single sawtooth waves f on the isoline is noted.

In cardiology, atrial fibrillation is also called atrial fibrillation.

In cases where the sinus rhythm driver loses its functions, the formation of non-sinus rhythms develops. IN clinical picture this is reflected in the form of various types of arrhythmias.

Thus, when analyzing sinus rhythm, there are three main pathological conditions:

1. - in this case, the correct one is observed, the frequency of contractions is more than 110 per minute. Among the causes of sinus tachycardia, clinicians highlight increased activity sympathetic division autonomic nervous system (this can be a variety of emotional or physical overload, decreased activity of the vagus nerve, damage to the sinoatrial node, various intoxications, infectious diseases or the effects of certain medications).
2. - an option in which there is a correct rhythm generated by the sinoatrial node, with a frequency of less than 50 beats per minute. The causes of bradycardia are opposite to the previous condition. These include an increase in the activity of the vagus nerve, a decrease in the influence of the sympathetic nervous system, different kinds hypoxia, extensive heart attacks myocardium, the influence of antiarrhythmics and cardiac glycosides, hypothyroidism, some infectious diseases.
3. Sinus arrhythmia - characterized by the fact that the rhythm is formed by the sinus driver, but the contraction frequency varies within limits exceeding 0.16 seconds. In this case, depending on the presence or absence of a clearly visible connection between heart rate intervals and the duration of respiratory cycles, we can talk about respiratory and non-respiratory sinus arrhythmia. The first, as a rule, characterizes the presence of an imbalance in the functioning of parts of the autonomic nervous system. The second variant of arrhythmia indicates organic damage the actual pacemaker. This may be coronary heart disease, various inflammatory changes in the myocardium, the toxic effect of cardiac glycosides.

• Irregular sinus rhythm
• Why does tachycardia occur?
• Is there any treatment? sinus arrhythmia?

A patient of a cardiologist, having received the result of an electrocardiogram, may encounter a record of irregular sinus rhythm. What is it connected with and is it worth thinking about your health? Such thoughts arise in a person’s head.

If an irregular rhythm is recorded in the cardiogram, then it is better to visit a doctor, since such a record indicates some heart problems. Only a specialist can correctly interpret the ECG results. Even a completely identical entry in the results of an elderly person and a teenager can mean completely different things.

Any person feels the beats of his own heart. Sometimes it seems to him that this is vital important organ beats faster, sometimes, on the contrary, it freezes. The electrocardiogram indicator “sinus rhythm” has two meanings: regular and irregular.

With an irregular rhythm, the heart rate may be increased or decreased. This state is called. And regular means a very good heart rate.

Irregular sinus rhythm

Such arrhythmia occurs when there are changes in the work of the heart: the intervals between its contractions are not equal, as they should be. But at the same time, the heart itself beats with a rhythm of 60-80 beats per minute, which is the norm. Arrhythmia is of two types: physiological and conditionally pathological.

Physiological, or respiratory, arrhythmia manifests itself in the following. When you exhale, your heart rate slows down, and when you inhale, it speeds up.

This is typical for children and adolescents. If a child's irregular breathing rhythm disappears, heart disease may subsequently develop.

Vegetative-vascular dystonia and recent infectious diseases can cause.

Pathological arrhythmia is characterized by either a decreased heart rate (bradycardia) or, conversely, an increased rate (tachycardia).

When the heart rate is less than 60 beats per minute.

Sometimes bradycardia develops into a pronounced form with a frequency of less than 40 beats. This condition is very dangerous as it can lead to fainting and complete cardiac arrest.

A decrease in heart rate is facilitated by:

• diets and fasting;
• changes in intracranial pressure;
• too much use of heart medications;
• diseases related to the thyroid gland;
• nicotine addiction;
• cardiosclerosis.

When the heart rate is more than 80 beats per minute. It can be caused, in addition to heart pathologies, by active physical activity, sudden excitement, and increased body temperature.

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Why does tachycardia occur?

Causes of tachycardia in the background pathological changes the following:

• increased arterial pressure(hypertension);
• heart diseases (heart disease, myocarditis, etc.);
• low blood pressure (hypotension);
• poisoning;
• infectious diseases;
• nerve diseases.

Regular or irregular sinus rhythm in a patient is shown by ECG. Additionally, the doctor may prescribe an ultrasound. It is very informative and reveals many pathological changes, but not about disturbances in the functioning of the sinus node, but about concomitant diseases.

The patient does not feel signs of the disease, since most often the arrhythmia is asymptomatic. Sometimes you just get the feeling that your heart is either freezing or jumping. And the child may complain that the heart is beating too fast. Healthy children do not feel heart rhythm.

Sinus rhythm of the heart refers to indicators of its work. The correct rhythm is set by the main pacemaker, which is the sinus node. In case of conduction disturbance, a phenomenon occurs with a corresponding change in both the rhythm itself and the quality of the heart, which immediately affects well-being.

The most in a simple way ECG is used to evaluate the correct functioning of the heart. It is this procedure that the therapist refers to if necessary. This is especially true for older patients, with whom it is impossible to begin to understand without printing out the cardiogram.

It is by the printout of the ECG, by the location of the teeth and the distance between them, that the specialist is able to assess the performance of the heart with a high probability.

Sinus rhythm of the heart is a constant contraction of all walls of the cardiac muscle membrane due to incoming electrical impulses from the main pacemaker - the sinus node. In the absence of any pathologies, the heart rhythm is sinus.

For reference. The sinus node is the largest group of atypical cardiomyocytes - cells responsible for the rhythmic heart pulsation.

This formation is localized in the upper part of the right atrium, at the confluence of the superior and inferior vena cava. The sinus node constantly creates electrical impulses, they go through each layer of the muscle membrane, causing the ventricles of the heart to contract. This process ensures a healthy heartbeat.

Sinus rhythm of the heart is an ECG value indicating the beating of the heart using impulses from the sinus node. When this value is normal, it can be argued that the sinus node is able to overcome electrical impulses created by other clusters of atypical cardiomyocytes.

What is characteristic of a normal heartbeat:

• The heart rate is numerically equal from 60 to 90;
• Heartbeats are created later equal amount time;
• The consistency of the beat is unchanged - the atria contract first, followed by the ventricles. This characteristic can be traced by the characteristic sound of the first and second tones, in addition - with an ECG;
• IN in good condition heartbeat may change when different condition person – physical activity, testing pain and others.

For reference. When the doctor concluded, “sinus rhythm frequency<60…90>, you can be calm about the functioning of the heart, since this condition is normal.

What types of sinus rhythm disorders can occur?

The ECG conclusion may have various errors. Even if the electrocardiogram demonstrates features of sinus rhythm, a person may develop pathological processes. It happens that despite the fact that electrical impulses are generated in the sinus node, the rhythmic cardiac pulsation does not satisfy the norm.

What pathologies of sinus rhythm are most common:

• An increased number of heart contractions may indicate that the patient has sinus tachycardia;
• On the contrary, a reduced number of heart beats may signal the development of sinus bradycardia;
• Irregularity of heart contractions, in other words arrhythmia, is characterized by the same frequency of beats that do not occur regularly. The specialist may also suspect that the patient has unexpected impulses occurring in the intervals between normal heart beats. Another pathology that irregular beats may indicate is sick sinus syndrome. This pathology is characterized by a stable, rare heartbeat, moments of “stopping” of cardiac activity, and in addition, the alternate occurrence of an accelerated and slowed down rhythm;
• Disturbed regularity of sinus rhythm indicates the absence of response reflexes in the muscular lining of the heart to stimuli from the environment.

Sinus rhythm with heart rate is normal

In addition to establishing the nature of cardiac pulsation and the leading pacemaker, heart rate is always determined on the ECG. As a rule, the device for taking an electrocardiogram copes with this task independently.

However, his conclusion is not true in all cases. It is much better when the attending doctor calculates the heart rate.

Important. Normal values sinus rhythm will have a number of heart beats in the range from 60 to 90 per minute. However, it must be remembered that not in all cases a shift in value in one direction or another can signal a disease.

For example, the number of heart beats can increase with excitement during the study, inner experiences cigarette smoked before the examination, physical activity before electrocardiography.

On the other hand, often in people who are actively involved in sports, a decrease in the number of heart beats is found, and the blood flow has normal characteristics. In this case, no deviation from the norm is observed.

Irregular sinus rhythm - what is it?

Sinus rhythm can be regular or irregular. With irregular sinus rhythm, the heart rate may become faster or slower. In this case, the number of heart beats corresponds to the norm, but the intervals between them are not equal. This condition is called arrhythmia. It has a physiological or conditionally pathological nature.

Attention. Physiological arrhythmia is closely related to the act of breathing. When a person inhales, the heart rate increases; when exhaling, it decreases. This condition typical for children.

Conditionally pathological arrhythmia can be expressed as both tachycardia and bradycardia. The causes of this condition can be heart pathologies, as well as diseases of the nervous system, infections, adherence to a strict diet, etc.

What does sinus rhythm look like on an ECG, normally and with pathologies?

Conclusion The ECG is called an electrocardiogram. It allows you to record the rhythmic contractions of the heart on paper in the form of a special graph. An ECG records information from a person’s limbs and cardiac zone. The sinus rhythm of the heart is determined using standard leads, which are designated by Roman numerals I, II, III.

Doctors analyze the following components of the electrocardiogram:

• P wave;
• P-Q distance;
• QRS complex;
• P-wave spacing;
• distance between R teeth;
• number of heart beats.

What does a recording of normal sinus heart rhythm look like?

P wave and P-Q interval

• The P wave is normally directed upward – positive;
• Regarding the R wave, which has the most large size, it is small;
• Appears before each QRS complex;
• There is normally a small distance between the P wave and the QRS complex (P-Q interval), and it is equal between these elements throughout the entire graph.

QRS complexes and R-R-R intervals

• The largest wave, the R wave, is directed upward in each QRS complex;
• The distances between all R waves are normally equal - this is an indicator of the regularity of heart beats.

P-P interval

As in the previous case, the norm is the same distance between the P waves.

What does sinus rhythm pathology look like on an ECG?

Not only bring to a person discomfort, but can also be a harbinger of serious heart disease.

Sinus tachycardia

If the patient has sinus tachycardia, the electrocardiogram shows following features:

• Heart rate exceeds the normal threshold and is more than 90 beats per minute;
• The regularity of sinus rhythm is maintained, the P wave always appears before the QRS complex;
• Ventricular complex (QRS) without deviations from the norm;
• Reducing the gap between P waves;
• Increased or decreased T wave height;
• The EOS (electrical axis of the heart) can be directed to the left, right, and up.

Sinus bradycardia

An electrocardiogram taken from a patient with sinus bradycardia is characterized by the following features:

• The number of heart beats per minute ranges from 40 to 60;
• No deviations in the alternation of P waves and ventricular complexes were detected;
• The P wave is reduced in size;
• The distance between P and Q ranges from 0.12 to 0.22 seconds.

Sinus arrhythmia

Irregularity of heart rhythm on electrocardiographic examination is detected in the following cases:

• Presence of P waves in all leads. In lead II it is positive, in avR it is always negative;
• Sometimes the distance between the R waves changes by more than 0.1 seconds, and this is dependent on breathing. In some cases, after a short interval, the longest one is recorded. Based on the distance between the R waves, the type of arrhythmia can be identified. If it is physiological in nature (more often in adolescents), then all changes in the interval occur smoothly and evenly. In the case of pathological arrhythmia, the change in intervals may have an abrupt character;
• In young patients, when holding their breath during inhalation, the transformation of intervals stops; in elderly people, this does not happen.

Sinus extrasystole

Sinus extrasystole on an ECG is detected by a number of specific signs:

• Too much early onset heart cycle P QRST normal in shape;
• The P wave of the extrasystole is normal and coincides with similar P waves during a standard heart contraction. The QRST complex of extrasystoles is exactly the same as usual;
• The pre-extrasystolic intervals of all sinus extrasystoles on the electrocardiogram are equal;
• Post-ectrasystolic intervals - the distance between the P waves - are equal to the intervals between cycles of the leading sinus rhythm of the heart, that is, there is no compensatory pause.

Sick sinus syndrome

Sick sinus syndrome (SSNS) is also detected during an electrocardiographic study. Wherein this pathology has several subspecies, each of which has various characteristics, detected on the electrocardiogram:

• SSSS - sinus bradycardia: the number of heart contractions is approximately 45-50 per minute;
• SSSU - sinoatrial block of the second degree Mobitz type 1: manifested by a smooth decrease in the distance between the P waves. The length of the stop is less than the previous distance between the P waves, multiplied by two;
• SSSU - second-degree sinoatrial block Mobitz type 2: the distances between the P waves are the same. The length of the stop is equal to twice the distance between the P teeth;
• SSSU – sinoatrial node arrest: the electrocardiogram records a level line on which there are no P waves;
• SSSS - bradycardia-tachycardia syndrome: the electrocardiogram records alternating supraventricular tachycardia and pause moments of the sinus node with a replacement slow ventricular increase in rhythm.

Features of rhythm in children

Normally, electrocardiogram indicators in young patients have special, different from adult ECG, peculiarities:

• The frequency of heart contractions depends on the age of the child: in children under 3 years of age, the heartbeat occurs at a frequency of 100-110 beats per minute, 3-5 years of age - about a hundred beats, 6-8 years of age - in the range from 90 to 100 , 9-12 years of age - 70-85 contractions in 60 seconds;
• The duration of the ventricular complex in small patients ranges from 0.06 to 0.1 seconds;
• The duration of the P wave does not exceed 0.1 seconds;
• The duration of the PQ complex is approximately 0.2 seconds;
• The duration of the QT complex does not exceed 0.4 seconds.

To assess the quality of functioning of the cardiac conduction system and form an idea of ​​the structure of the myocardium, a fairly simple study is used - electrocardiography.

This technique helps in making a diagnosis in heart patients, is a screening procedure for identifying cardiac disorders, and is carried out before surgical interventions. Often the first phrase when ECG decoding sinus rhythm is indicated, what is it?

Nature of ECG

An electrocardiogram is a graphical representation electrical processes, occurring in the heart. The rhythmic contraction of the myocardium is associated with the emergence and passage of impulses along the autonomic nerve pathways of this organ.

The hierarchy of structures of the conduction system of the heart is represented by the sinus and atrioventricular nodes (AV), the His bundle and Purkinje fibers. Each of these components is capable of generating pulses with a certain frequency.

The source of healthy automaticity is the sinoatrial node (SA or SU), which suppresses the activity of other units. In this case, register on ECG sinus rhythm. On the contrary, as a result of activation of heterotopic foci of impulses, arrhythmias develop.

ECG interpretation includes analysis of the resulting curve during the study. The film shows various teeth and spaces between them, which correspond to the propagation of the excitation wave through the heart.

Main components of a cardiogram:

What could the rhythm be?

The normal functioning of the main source of automatism is indicated by a correct sinus rhythm with a frequency of 60–90 impulses per minute.

It should be noted that the distance between adjacent P waves, as well as QRS complexes, should be the same. In addition, all components on the ECG must comply with their duration standards.

Changes in intervals or expansion of complexes, while maintaining correct ratios between P waves and 1:1 ventricular beats indicates abnormal sinus rhythm, presence of blocks (slow conduction), or arrhythmia.

What is arrhythmia?

Arrhythmia literally means a lack of rhythm in the generated impulses. There is a physiological (respiratory) form and a pathological one, which can occur directly from the sinus node or during migration of the pacemaker (for example, atrial, from the AV junction).

Respiratory arrhythmia practically does not change the picture on the ECG. Its presence is distinguished cyclical changes the distances between the P waves associated with the act of “inhalation-exhalation”.

During electrocardiogram recording functional diagnostician may ask the subject to stop breathing for a few seconds to ascertain the nature of the arrhythmia.

When exhalation is held, sinus rhythm is reflected at regular intervals on the ECG film.

Classification of arrhythmias

1)

a) physiological;

b) pathological.

2) Non-sinus arrhythmia: atrial;

a) ventricular;

b) from the atrioventricular connection.

There are tachyarrhythmias, bradycardia (heart rhythm disturbances with increased or decreased heart rate), various blockades, and extrasystoles.

The most common non-sinus arrhythmias

If with each recorded cycle changes in the P wave and the PQ interval are recorded on film, a gradual inversion (decrease followed by reaching a negative value) of the P wave is observed, such a cardiogram indicates the presence of pacemaker migration.

This phenomenon is the result of a change in the main source of impulses (SU) to the atrioventricular connection. Pacemaker migration can reach the level of ventricular structures, but this phenomenon is very rare.

Common disorders include junctional rhythm. In such a situation, the atrioventricular node takes on the leading role in generating impulses.

In this case, an altered P wave is recorded on the ECG (negative, biphasic), there are deviations from the interval reflecting conduction through the atria, the heart rate is 40–60 beats per minute.

A junctional rhythm is said to occur when there are 6 or more consecutive impulses from the AV junction.

A special category of rhythm disturbances is atrial fibrillation(atrial fibrillation). In this case, the separate P-P cycles and QRS complexes as a result of the decoupling of sinus impulses and ventricular activity.

In critical cases, the rhythm of ventricular fibrillation and flutter is recorded on the ECG. As a rule, this type is diagnosed during resuscitation measures, requiring intensive care and defibrillation.

Extrasystoles

Episodes ectopic activity from various representatives of the conduction system can disrupt the harmonious picture ECG rhythm. Such impulses lead to an extraordinary contraction of the heart or a small part of it.

Extrasystole can be atrial, from the AV node, ventricular, manifested from one specific area or several at once. There are single and group (2, 3 or 4 extrasystoles).

Even healthy people Several episodes of ES are recorded per day. There are often cases when, to establish a pathological extrasystole, it is necessary to carry out daily monitoring ECG, as well as for paroxysms of atrial fibrillation.

Depending on the severity and number of episodes of extraordinary contractions, the doctor chooses the tactics for managing the patient.

Conduction disorders

Changes in the duration of intervals, waves and the ventricular complex mainly reflect blocking of impulses in the conduction system or confirm an increase in the myocardial walls.

There is also a syndrome of shortened PQ, associated with the presence of shortened paths to the AV junction and, accordingly, rapid conduction of biopotentials from the main source of automaticity to the ventricles. The presence of this condition increases the risk of arrhythmias.

Among the blockades there are:

• intraatrial;
• sinoatrial;
• several types of atrioventricular blocks;
• intraventricular (pedicles and branches of the His bundle).

As a rule, objective complaints are associated with the presence of sinus blockades and slowing of conduction from the AV node.

To simplify conductivity assessment, you can use the 0.1±0.02 rule. This means that any tooth, interval, or entire complex must not exceed the given duration in seconds. An increase above 0.12 indicates the presence of a blockade. LBBB and RBBB have characteristic M and W shapes in the precordial leads.

Example of a normal ECG description

The conclusion of an ideal cardiogram without pathology will indicate: sinus rhythm, correct, heart rate (from 60 to 90 in an adult), normal position of the electrical axis of the heart.

Vertical and horizontal EOS are also variants of the norm (depending on the patient’s constitution) for asthenic people and hypersthenics, respectively.

Bundle branch blocks are often presented as an electrocardiographic finding and do not affect the health status of the patient.