ECG measurement Deciphering a regular ECG will reveal all the heart's secrets. The irreducible elements of the heart include

Pathology of cardio-vascular system is one of the most common problems that affects people of all ages. Timely treatment and diagnosis of the circulatory system can significantly reduce the risk of developing dangerous diseases.

Today, the most effective and easily accessible method for studying heart function is an electrocardiogram.

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

• Teeth;
• Intervals;
• Segments.

Not only their presence or absence is assessed, but also their height, duration, location, direction and sequence.

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

Cardiogram analysis

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

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

Sinus rhythm of the heart

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

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

Heart rate

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

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

Excitation source

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

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

You can read detailed and comprehensive information about the symptoms of cardiac cardiosclerosis.

Conductivity

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

Electric axis

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

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

In cases where there is a tilt of more than 90° or more than -30°, there is a serious disruption of the His bundle.

Teeth, segments and intervals

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

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

Intervals are ECG sections lying on the isoline.

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

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

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

Normal for men and women

ECG interpretation heart and normal indicators in adults are presented in this table:

Healthy Childhood Outcomes

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

Dangerous diagnoses

Which dangerous conditions can it be determined by ECG readings during decoding?

Extrasystole

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

If extrasystoles appear no more than 5 times per hour, then they cannot cause significant harm to health.

Arrhythmia

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

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

Bradycardia

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

Tachycardia

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

Conduction disturbance

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

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

Many factors can lead to disruptions in the functioning of the heart muscle itself. Tumors develop, muscle nutrition is disrupted, and depolarization processes are disrupted. Most of these pathologies require serious treatment.

Why there might be differences in performance

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

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

Additional examination techniques

Holter

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

Treadmill

Unlike a conventional ECG, which is recorded at rest, this method based on analysis of results after physical activity. This is most often used for risk assessment 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 and the risks of developing endo- and rheumatic carditis.

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

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

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

An electrocardiogram is a very simple and informative method, which allows you to study the functioning of the human heart and determine the causes of pain in the heart. Using an ECG, you can evaluate the heart rhythm and the condition of the heart muscle itself. The result of an electrocardiographic study looks like incomprehensible, at first glance, lines on a piece of paper. At the same time, they contain information about the condition and functioning of the heart. Interpretation of ECG indicators should be carried out an experienced doctor, but if you know how to interpret an ECG, you can independently evaluate the work of your heart.

ECG heart data appears as alternating waves, flat intervals, and segments. These elements are located on an isoline. You need to understand what these elements mean:

• Waves on an ECG are bumps that point downward (negative) or upward (positive). The P wave on the ECG means the work of the cardiac atria, and the T wave on the ECG reflects the recovery capabilities of the myocardium;
• Segments on an ECG are the distance between several teeth that are nearby. The most important indicators of the segments on the ECG are ST and PQ. The duration of the ST segment on the ECG is influenced by the pulse rate. The PQ segment on the ECG reflects the penetration of biopotential into the ventricles through the ventricular node directly to the atrium;
• An interval on an ECG is a gap that includes both a segment and a wave. Roughly speaking, this is 1 tooth with a piece of isoline. For diagnostics great importance have PQ and QT intervals.

A total of 12 curves are recorded on the cardiogram. When interpreting an ECG, you must pay attention to the heart rhythm, electrical axis, interval conduction, QRS complexes, ST segments and waves.

To decipher an ECG, you need to know what period of time fits into one cell. The standard indicators are as follows: a cell of 1 mm is equal to 0.04 seconds at a speed of 25 mm/s.

The intervals between the R waves should be equal, this determines the rhythm of the human heart. By counting the number of cells between the R waves and knowing the recording speed, you can also determine the heart rate (HR). The normal heart rate when deciphering an ECG is from 60 to 90 heart beats per minute. Calculating heart rate on an ECG is very simple. If the speed of the tape is 50 mm/s, then heart rate = 600/ per number of large squares.

By assessing the P wave, you can determine the source of excitation in the heart muscle. The ECG transcript shows sinus rhythm - the norm for a healthy person.

It is also worth paying attention to the displacement of the electrical axis of the heart. If the displacement is sharp, then this indicates problems with the cardiovascular system.

On the ECG, the decoding of the norm should look like this:

• The heart rate should be sinus;
• Normal indicator heart rate - 60-90 beats/min;
• QT intervals - 390-450 ms.
• EOS - it is always calculated based on the isoline. The height of the teeth is taken as a basis. The norm assumes that R exceeds S in height. If the ratio is the opposite, the likelihood of ventricular disease is high;
• QRS - when studying this complex, pay attention to its width. Normally it can reach 120 ms. There should also be no pathological Q;
• ST - the norm assumes being on the isoline. The T wave is directed upward and is characterized by asymmetry.

Prolongation of intervals may indicate atherosclerosis, myocardial infarction, etc. And with shortened intervals, the presence of hypercalcemia can be assumed.

Reading ECG waves.

• P - reflects the excitation of the right and left atria; this wave must be positive. It consists half of excitation of the right atrium and half of excitation of the left atrium;
• Q - is responsible for excitation of the interventricular septum. It's always negative. Its normal value is considered to be ¼ R at 0.3 s. An increase in the normal value indicates myocardial pathology;
• R is the excitation vector of the apex of the heart. It determines the activity of the walls of the ventricles. Must be determined on each lead. Otherwise, ventricular hypertrophy is assumed;
• S - the tooth is negative, its height should be 20 mm. It is also worth paying attention to the ST segment. Its deviations indicate myocardial ischemia;
• T - usually directed upward in the first and second leads, in VR it has a negative value. A change in the indicator indicates the presence of hyper- or hypokalemia.

Waves of a normal human ECG: indicators in the table

Video

Decoding ECG - rhythms.

The rhythm when deciphering the ECG is of great importance. The normal rhythm when interpreting the ECG is sinus. And all the rest are pathological.

With sinus rhythm on the electrocardiogram in lead II, the P wave is present before each QRS complex, and it is always positive. In one lead, all P waves should have the same shape, length and width.

With atrial rhythm, the P wave in leads II and III is negative, but is present before each QRS complex.

Atrioventricular rhythms are characterized by the absence of P waves on cardiograms, or the appearance of this wave after the QRS complex, and not before it, as is normal. With this type of rhythm, the heart rate is low, ranging from 40 to 60 beats per minute.

Ventricular rhythm is characterized by an increase in the width of the QRS complex, which becomes large and quite frightening. The P waves and the QRS complex are completely unrelated to each other. That is, there is no strict correct normal sequence - the P wave, followed by the QRS complex. Ventricular rhythm is characterized by a decrease in heart rate - less than 40 beats per minute.

Interpretation of ECG in adults: the norm in the table

Analysis of the position of the teeth on the ECG and measurement of the distance between the high teeth R and R are indicators of the cardiogram that may indicate a normal ECG in adults.

The maximum difference between high R and R waves can be 10%, ideally they should be equal. If the sinus rhythm is slow, then this indicates bradycardia, and if it is frequent, then the patient has tachycardia.

Table of indicators of cardiogram norms in adults

The cardiogram may separately indicate deviations from the norm and specific syndromes. This is indicated if the cardiogram is pathological. Separately, violations and changes in the parameters of segments, intervals and teeth are also noted.

Normal ECG in children.

ECG normal a child’s reading is quite different from an adult’s reading and looks like this:

• The baby's heart rate is quite high. Up to 110 blows in children under 3 years old, up to 100 blows in children from 3 to 5 years old. 60 to 90 strokes for teenagers;
• The rhythm should be sinus;
• The normal P wave in children is up to 0.1 s;
• the QRS complex can have values ​​of 0.6-0.1 s;
• PQ - can fluctuate within 0.2 s;
• QT up to 0.4 s;

The electrocardiogram of the heart is the main diagnostic study, allowing one to draw conclusions about the functioning of the organ, the presence or absence of pathologies and the degree of their severity. The interpretation of the ECG of the heart is carried out by a cardiologist who sees not only the curves on paper, but can also visually assess the patient’s condition and analyze his complaints.

The indicators, collected all together, help make the correct diagnosis. Without making an accurate diagnosis it is impossible to prescribe effective treatment, so doctors especially carefully study the patient’s ECG results.

Brief information about the ECG procedure

Electrocardiography examines electric currents, arising during the work of the human heart. This method is quite simple and accessible - these are the main advantages diagnostic procedure, which has been carried out by doctors for quite a long time and doctors have accumulated sufficient practical experience regarding the interpretation of results.

The heart cardiogram was developed and implemented in its modern form at the beginning of the twentieth century by the Dutch scientist Einthoven. The terminology developed by the physiologist is still used to this day. This once again proves that ECG is a relevant and in-demand study, the indicators of which are extremely important for diagnosing heart pathologies.

Cardiogram value

An electrocardiogram is extremely important, since its correct reading makes it possible to detect serious pathologies, on the timely diagnosis of which the patient’s life depends. A cardiogram is performed in both adults and children.

Upon receipt of the results, the cardiologist can evaluate the frequency of heart contractions, the presence of arrhythmia, metabolic pathologies in the myocardium, disturbances in electrical conductivity, myocardial pathologies, localization of the electrical axis, and the physiological state of the main human organ. In some cases, a cardiogram can confirm other somatic pathologies that are indirectly related to cardiac activity.

Important! Doctors recommend doing a cardiogram if the patient experiences obvious changes in heart rhythm, suffers from sudden shortness of breath, weakness, or faints. It is necessary to do a cardiogram in case of primary pain in the heart, as well as in those patients who have already been diagnosed with abnormalities in the functioning of the organ and experience murmurs.

An electrocardiogram is a standard procedure when undergoing a medical examination, in athletes during medical examination, in pregnant women, and before surgical interventions. An ECG with and without exercise has diagnostic value. A cardiogram is done for pathologies of the endocrine and nervous systems, and for increased lipid levels. For the purpose of prevention, it is recommended to do heart diagnostics for all patients who have reached forty-five years of age - this will help to identify abnormal organ performance, diagnose pathology and begin therapy.

What are the results of the study?

The results of the study will be absolutely incomprehensible to dummies, so you cannot read a heart cardiogram yourself. The doctor receives from the electrocardiograph a long graph paper with curves printed on it. Each graph reflects an electrode attached to the patient's body at a certain point.

In addition to graphs, devices can provide other information, for example, basic parameters, the norm of one or another indicator. The preliminary diagnosis is generated automatically, so the doctor needs to independently study the results and only take into account what the device gives in terms of possible illness. Data can be recorded not only on paper, but also on electronic media, as well as in the device’s memory.

Interesting! A type of ECG is Holter monitoring. If the cardiogram is taken in the clinic in a few minutes with the patient lying down, then with Holter monitoring the patient receives a portable sensor, which he attaches to his body. The sensor must be worn for a full day, after which the doctor reads the results. The peculiarity of such monitoring is the dynamic study of cardiac activity in various conditions. This allows you to get a more complete picture of the patient's health status.

Decoding the research results: main aspects

Curves on graph paper are represented by an isoline - a straight line, which means there are no impulses at the moment. Deviations up or down from the isoline are called teeth. In one full cycle heart rate There are six teeth, which are assigned standard letters of the Latin alphabet. Such teeth on the cardiogram are either directed upward or downward. The upper teeth are considered positive, and the downward ones are considered negative. Normally, the S and Q waves fall slightly downward from the isoline, and the R wave is a peak rising upward.

Each tooth is not just a picture with a letter; behind it lies a certain phase of the heart’s work. You can decipher a cardiogram if you know which teeth mean what. For example, the P wave demonstrates the moment when the atria are relaxed, R indicates the excitation of the ventricles, and T indicates their relaxation. Doctors take into account the distances between the teeth, which also has its own diagnostic value, and if necessary, entire groups of PQ, QRS, ST are examined. Each research value indicates a certain characteristic of the organ.

For example, if the distance between the R waves is unequal, doctors talk about extrasystole, atrial fibrillation, and weakness of the sinus node. If the P wave is elevated and thickened, this indicates thickening of the walls of the atria. An extended PQ interval indicates artrioventicular block, and an expanded QRS suggests ventricular hypertrophy and His bundle block. If there are no gaps in this segment, doctors suspect fibrillation. A prolonged QT interval indicates serious heart rhythm disturbances that can be fatal. And if this QRS combination is presented in the form of a flag, then doctors talk about myocardial infarction.

Table of normal values ​​and other indicators

To interpret the ECG, there is a table containing the normal values. Based on it, doctors can see deviations. As a rule, in the process of long-term work with cardiac patients, doctors no longer use a table at hand; in adults, they have learned the norm by heart.

In addition to the table values, doctors also consider other parameters of the heart:

• rhythm of heart contractions– in the presence of arrhythmia, i.e. disruptions in the rhythm of contractions of the heart muscle, the difference between the indices of the teeth will be more than ten percent. People with a healthy heart have a normosystole, but pathological data make the doctor wary and look for abnormalities. The exception is sinus arrhythmia in combination with sinus rhythm, as often happens in adolescence, but in adults, sinus rhythm with deviations indicates the onset of the development of pathology. A striking example of deviations is extrasystole, which manifests itself in the presence of additional contractions. It occurs with cardiac malformations, myocardial inflammation, ischemia;
• heart rate– the most accessible parameter, you can evaluate it yourself. Normally, in one minute there should be from 60 to 80 complete cycles of the heart. With an accelerated cycle, more than 80 beats indicate tachycardia, but less than 60 is bradycardia. The indicator is more illustrative, since not all severe pathologies give rise to bradycardia or tachycardia, and in isolated cases, the ECG of a healthy person will also show such phenomena if he is nervous during electrocardiography.

Heart Rate Types

An electrocardiogram shows another important parameter - the type of heart rhythm. It refers to the place from which the signal travels, causing the heart to contract.

There are several rhythms - sinus, atrial, ventricular and atrioventricular. The norm is sinus rhythm, and if the impulse occurs in other places, then this is considered a deviation.

Atrial rhythm on ECG is a nerve impulse originating in the atria. Atrial cells provoke the appearance of ectopic rhythms. This situation arises when the functioning of the sinus node is disrupted, which should produce these rhythms on its own, and now the atrial innervation centers do it for it. The immediate cause of this deviation is hypertension, weakness of the sinus node, ischemic disorders, some endocrine pathologies. With such an ECG, nonspecific ST-T changes are recorded. In some cases, atrial rhythm is observed in healthy people.

Atrioventricular rhythm occurs at the node of the same name. The pulse rate with this type of rhythm falls below 60 beats/min, which indicates bradycardia. The causes of atrioventricular rhythm are a weak sinus node, taking certain medications, and blockage of the AV node. If tachycardia occurs during atrioventricular rhythm, this is evidence of earlier suffered a heart attack, rheumatic changes, such a deviation appears after surgical interventions on the heart.

Ventricular rhythm is the most severe pathology. The impulse emanating from the ventricles is extremely weak, contractions often fall below forty beats. This rhythm occurs in heart attack, circulatory failure, cardiosclerosis, heart defects, and in the preadgonal state.

When deciphering the analysis, doctors pay attention to the electrical axis. It is reflected in degrees and demonstrates the direction of the moving impulses. The norm for this indicator is 30-70 degrees when tilted to the vertical. Deviations from the norm suggest intracardiac blockades or hypertension.

When decoding the ECG, terminological conclusions are issued, which also demonstrate normality or pathology. A bad ECG or a result without pathology will show all the indicators of heart function in combination. Atrioventricular block will be reflected as a prolonged PQ interval. Such a deviation in the first degree does not threaten the patient’s life. But with the third degree of pathology, there is a risk of sudden cardiac arrest, since the atria and ventricles work in their own incompatible rhythm.

If the conclusion contains the word “ectopic rhythm,” this means that the innervation does not come from the sinus node. The condition is both a variant of the norm and a severe deviation due to cardiac pathologies, intake medicines etc.

If the cardiogram shows nonspecific ST-T changes, then this situation requires additional diagnostics. The cause of the deviation may be metabolic disorders, imbalance of essential electrolytes or endocrine dysfunction. A high T wave may indicate hypokalemia, but is also a normal variant.

In some heart pathologies, the conclusion will show low voltage - the currents emanating from the heart are so weak that they are recorded below normal. Low electrical activity occurs due to pericarditis or other cardiac pathologies.

Important! A borderline ECG of the heart indicates a deviation of some parameters from the norm. This output is generated by the electrocardiograph system and does not mean serious violations. When receiving such data, patients should not be upset - they just need to undergo additional examination, identify the cause of the disorders and treat the underlying disease.

Myocardial infarction on ECG

An ECG during myocardial infarction records extremely important diagnostic data, which can be used not only to diagnose a heart attack, but also to determine the severity of the disorders. The manifestation of pathology on the ECG will be noticeable already when the symptoms of a crisis begin. There will be no R wave on the millimeter tape - this is one of the leading signs of myocardial infarction.

The second obvious sign is the registration of an abnormal Q wave, the excitation time of which is no more than 0.03 s. The pathological Q wave occurs in those leads where it was not previously recorded. Abnormal displacement also indicates a heart attack. section S-T below the isoline, which is called the cat's back because of the characteristic winding lines, there is a negative T wave. Based on the cardiogram data, doctors make a diagnosis and prescribe treatment.

The value of the ECG is extremely important for people suffering from heart pathologies. Basic data obtained during interpretation of the ECG of the heart allows the doctor to suspect pathological heart function at an early stage. Taking into account the fact that the organ is innervated independently and does not depend on other indicators, it is the registration of electrical impulses that will have a decisive diagnostic value.

7.2.1. Myocardial hypertrophy

The cause of hypertrophy, as a rule, is excessive load on the heart, either by resistance (arterial hypertension) or volume (chronic renal and/or heart failure). Increased work of the heart leads to an increase in metabolic processes in the myocardium and is subsequently accompanied by an increase in the number of muscle fibers. The bioelectrical activity of the hypertrophied part of the heart increases, which is reflected in the electrocardiogram.

7.2.1.1. Left atrial hypertrophy

A characteristic feature Left atrial hypertrophy is an increase in the width of the P wave (more than 0.12 s). The second sign is a change in the shape of the P wave (two humps with a predominance of the second peak) (Fig. 6).

Rice. 6. ECG for left atrial hypertrophy

Left atrial hypertrophy is a typical symptom of mitral valve stenosis and therefore the P wave in this disease is called P-mitrale. Similar changes are observed in leads I, II, aVL, V5, V6.

7.2.1.2. Right atrial hypertrophy

With hypertrophy of the right atrium, changes also affect the P wave, which takes on a pointed shape and increases in amplitude (Fig. 7).

Rice. 7. ECG for hypertrophy of the right atrium (P-pulmonale), right ventricle (S-type)

Hypertrophy of the right atrium is observed with atrial septal defect, hypertension of the pulmonary circulation.

Most often, such a P wave is detected in diseases of the lungs; it is often called P-pulmonale.

Right atrium hypertrophy is a sign of changes in the P wave in leads II, III, aVF, V1, V2.

7.2.1.3. Left ventricular hypertrophy

The ventricles of the heart are better adapted to stress, and in the early stages their hypertrophy may not appear on the ECG, but as the pathology develops, characteristic signs become visible.

With ventricular hypertrophy, the ECG shows significantly more changes than with atrial hypertrophy.

The main signs of left ventricular hypertrophy are (Fig. 8):

Deviation of the electrical axis of the heart to the left (levogram);

Shift of the transition zone to the right (in leads V2 or V3);

The R wave in leads V5, V6 is high and larger in amplitude than RV4;

Deep S in leads V1, V2;

Expanded QRS complex in leads V5, V6 (up to 0.1 s or more);

Bias S-T segment below the isoelectric line with the convex upward;

Negative T wave in leads I, II, aVL, V5, V6.

Rice. 8. ECG for left ventricular hypertrophy

Left ventricular hypertrophy is often observed with arterial hypertension, acromegaly, pheochromocytoma, as well as mitral and aortic valve insufficiency, congenital defects hearts.

7.2.1.4. Right ventricular hypertrophy

Signs of right ventricular hypertrophy appear on the ECG in advanced cases. Diagnosis at the early stage of hypertrophy is extremely difficult.

Signs of hypertrophy (Fig. 9):

Deviation of the electrical axis of the heart to the right (pravogram);

Deep S wave in lead V1 and high R wave in leads III, aVF, V1, V2;

The height of the RV6 tooth is less than normal;

Expanded QRS complex in leads V1, V2 (up to 0.1 s or more);

Deep S wave in lead V5 and also V6;

Displacement of the S-T segment below the isoline with convexity upward in the right III, aVF, V1 and V2;

Complete or incomplete blockade of the right bundle branch;

Shift the transition zone to the left.

Rice. 9. ECG for right ventricular hypertrophy

Right ventricular hypertrophy is most often associated with increased pressure in the pulmonary circulation in pulmonary diseases, mitral valve stenosis, mural thrombosis and stenosis pulmonary artery and congenital heart defects.

7.2.2. Rhythm disorders

Weakness, shortness of breath, rapid heartbeat, frequent and difficult breathing, interruptions in heart function, a feeling of suffocation, fainting or episodes of loss of consciousness may be manifestations of cardiac arrhythmias due to cardiovascular diseases. An ECG helps confirm their presence, and most importantly determine their type.

It should be remembered that automatism is unique property cells of the conduction system of the heart, and the sinus node, which controls the rhythm, has the greatest automaticity.

Rhythm disturbances (arrhythmias) are diagnosed in cases where there is no sinus rhythm on the ECG.

Signs of normal sinus rhythm:

P wave frequency – ranging from 60 to 90 (per 1 min);

Identical duration of R-R intervals;

Positive P wave in all leads except aVR.

Heart rhythm disturbances are very diverse. All arrhythmias are divided into nomotopic (changes develop in the sinus node itself) and heterotopic. In the latter case, excitatory impulses arise outside the sinus node, that is, in the atria, atrioventricular junction and ventricles (in the branches of the His bundle).

Nomotopic arrhythmias include sinus brady and tachycardia and irregular sinus rhythm. Heterotopic - atrial fibrillation and flutter and other disorders. If the occurrence of arrhythmia is associated with a dysfunction of excitability, then such rhythm disturbances are divided into extrasystole and paroxysmal tachycardia.

Considering the variety of types of arrhythmias that can be detected on an ECG, the author, in order not to bore the reader with the intricacies of medical science, allowed himself only to define the basic concepts and consider the most significant rhythm and conduction disorders.

7.2.2.1. Sinus tachycardia

Increased generation of impulses in the sinus node (more than 100 impulses per minute).

On the ECG it is manifested by the presence of a normal P wave and a shortening of the R-R interval.

7.2.2.2. Sinus bradycardia

The pulse generation frequency in the sinus node does not exceed 60.

On the ECG it is manifested by the presence of a normal P wave and a prolongation of the R-R interval.

It should be noted that with a contraction frequency of less than 30, bradycardia is not sinus.

In both cases of tachycardia and bradycardia, the patient is treated for the disease that caused the rhythm disturbance.

7.2.2.3. Irregular sinus rhythm

Impulses are generated irregularly in the sinus node. The ECG shows normal waves and intervals, but the duration of the R-R intervals differs by at least 0.1 s.

This type of arrhythmia can occur in healthy people and does not require treatment.

7.2.2.4. Idioventricular rhythm

Heterotopic arrhythmia, in which the pacemaker is either the bundle branches or the Purkinje fibers.

Extremely severe pathology.

A rare rhythm on the ECG (that is, 30–40 beats per minute), the P wave is absent, the QRS complexes are deformed and widened (duration 0.12 s or more).

Occurs only in severe heart pathology. A patient with such a disorder requires emergency care and is subject to immediate hospitalization in a cardiac intensive care unit.

7.2.2.5. Extrasystole

Extraordinary contraction of the heart caused by a single ectopic impulse. Of practical importance is the division of extrasystoles into supraventricular and ventricular.

A supraventricular (also called atrial) extrasystole is recorded on an ECG if the focus causing extraordinary excitation (contraction) of the heart is located in the atria.

Ventricular extrasystole is recorded on the cardiogram when an ectopic focus is formed in one of the ventricles.

Extrasystole can be rare, frequent (more than 10% of heart contractions in 1 minute), paired (bigemeny) and group (more than three in a row).

Let us list the ECG signs of atrial extrasystole:

P wave changed in shape and amplitude;

The P-Q interval is shortened;

A prematurely recorded QRS complex does not differ in shape from the normal (sinus) complex;

The R-R interval that follows the extrasystole is longer than usual, but shorter than two normal intervals (incomplete compensatory pause).

Atrial extrasystoles are more common in older people against the background of cardiosclerosis and coronary disease heart, but can also be observed in practically healthy people, for example, if a person is very worried or experiencing stress.

If extrasystole is noticed in a practically healthy person, then treatment consists of prescribing Valocordin, Corvalol and ensuring complete rest.

When registering an extrasystole in a patient, treatment of the underlying disease and taking antiarrhythmic drugs from the isoptin group are also required.

Signs of ventricular extrasystole:

The P wave is absent;

The extraordinary QRS complex is significantly widened (more than 0.12 s) and deformed;

Full compensatory pause.

Ventricular extrasystole always indicates heart damage (ischemic heart disease, myocarditis, endocarditis, heart attack, atherosclerosis).

In case of ventricular extrasystole with a frequency of 3–5 contractions per 1 minute, antiarrhythmic therapy is mandatory.

Lidocaine is most often administered intravenously, but other drugs can also be used. Treatment is carried out with careful ECG monitoring.

7.2.2.6. Paroxysmal tachycardia

Sudden attack ultra-frequent contractions, lasting from a few seconds to several days. The heterotopic pacemaker is located either in the ventricles or supraventricularly.

With supraventricular tachycardia (in this case, impulses are formed in the atria or atrioventricular node), the correct rhythm is recorded on the ECG with a frequency of 180 to 220 contractions per minute.

QRS complexes are not changed or widened.

With ventricular form paroxysmal tachycardia P waves may change their location on the ECG, QRS complexes are deformed and widened.

Supraventricular tachycardia occurs in Wolff–Parkinson–White syndrome, less commonly in acute heart attack myocardium.

The ventricular form of paroxysmal tachycardia is detected in patients with myocardial infarction, with ischemic heart disease, and electrolyte metabolism disorders.

7.2.2.7. Atrial fibrillation(atrial fibrillation)

A type of supraventricular arrhythmias caused by asynchronous, uncoordinated electrical activity of the atria with subsequent deterioration of their contractile function. The flow of impulses is not carried out entirely to the ventricles, and they contract irregularly.

This arrhythmia is one of the most common heart rhythm disturbances.

It occurs in more than 6% of patients over 60 years of age and in 1% of patients younger than this age.

Signs of atrial fibrillation:

R-R intervals are different (arrhythmia);

There are no P waves;

Flicker waves are recorded (they are especially clearly visible in leads II, III, V1, V2);

Electrical alternation (different amplitudes of the I waves in one lead).

Atrial fibrillation occurs when mitral stenosis, thyrotoxicosis and cardiosclerosis, and also often with myocardial infarction. Medical care is to restore sinus rhythm. Procainamide, potassium preparations and other antiarrhythmic drugs are used.

7.2.2.8. Atrial flutter

It is observed much less frequently than atrial fibrillation.

With atrial flutter, normal excitation and contraction of the atria are absent and excitation and contraction of individual atrial fibers are observed.

7.2.2.9. Ventricular fibrillation

The most dangerous and severe rhythm disorder, which quickly leads to cessation of blood circulation. Occurs during myocardial infarction, as well as in the terminal stages of various cardiovascular diseases in patients who are in a state of clinical death. In case of ventricular fibrillation, urgent resuscitation measures are required.

Signs of ventricular fibrillation:

Absence of all teeth of the ventricular complex;

Registration of fibrillation waves in all leads with a frequency of 450–600 waves per 1 min.

7.2.3. Conduction disorders

Changes in the cardiogram that occur in the event of a disturbance in the conduction of an impulse in the form of a slowdown or complete cessation of the transmission of excitation are called blockades. Blockades are classified depending on the level at which the violation occurred.

There are sinoatrial, atrial, atrioventricular and intraventricular blockades. Each of these groups is further subdivided. For example, there are sinoatrial blockades I, II and III degree, blockade of the right and left bundle branches. There is also a more detailed division (blockade of the anterior branch of the left bundle branch, incomplete block of the right bundle branch). Among conduction disorders recorded using ECG, the following blockades are of greatest practical importance:

Sinoatrial III degree;

Atrioventricular I, II and III degrees;

Blockade of the right and left bundle branches.

7.2.3.1. III degree sinoatrial block

A conduction disorder in which the conduction of excitation from the sinus node to the atria is blocked. On a seemingly normal ECG, the next contraction suddenly disappears (is blocked), that is, the entire P-QRS-T complex (or 2-3 complexes at once). An isoline is recorded in their place. The pathology is observed in those suffering from coronary artery disease, heart attack, cardiosclerosis, and when using a number of drugs (for example, beta blockers). Treatment consists of treating the underlying disease and using atropine, isadrin and similar agents).

7.2.3.2. Atrioventricular block

Impaired conduction of excitation from the sinus node through the atrioventricular connection.

Slowing of atrioventricular conduction is first degree atrioventricular block. Manifests itself on the ECG as a prolongation of the P-Q interval (more than 0.2 s) with a normal heart rate.

Second degree atrioventricular block is an incomplete block in which not all impulses coming from the sinus node reach the ventricular myocardium.

On the ECG, the following two types of blockade are distinguished: the first is Mobitz-1 (Samoilov-Wenckebach) and the second is Mobitz-2.

Signs of Mobitz-1 type blockade:

Constantly lengthening P interval

As a result of the first sign, at some stage after the P wave the QRS complex disappears.

A sign of Mobitz-2 type block is the periodic loss of the QRS complex against the background of an extended P-Q interval.

Third degree atrioventricular block is a condition in which not a single impulse coming from the sinus node is carried to the ventricles. The ECG records two types of rhythm that are not related to each other; the work of the ventricles (QRS complexes) and the atria (P waves) is not coordinated.

Third degree blockade often occurs in cardiosclerosis, myocardial infarction, and improper use of cardiac glycosides. The presence of this type of blockade in a patient is an indication for his urgent hospitalization in a cardiology hospital. Atropine, ephedrine and, in some cases, prednisolone are used for treatment.

7.2.Z.Z. Bundle branch blocks

In a healthy person, an electrical impulse originating in the sinus node, passing through the branches of the His bundle, simultaneously excites both ventricles.

When the right or left bundle branch is blocked, the impulse path changes and therefore the excitation of the corresponding ventricle is delayed.

Incomplete blockades and so-called blockades of the anterior and posterior branches of the bundle branch are also possible.

Signs of complete blockade of the right bundle branch (Fig. 10):

Deformed and widened (more than 0.12 s) QRS complex;

Negative T wave in leads V1 and V2;

Displacement of the S-T segment from the isoline;

Widening and splitting of the QRS in leads V1 and V2 in the form of RsR.

Rice. 10. ECG with complete block of the right bundle branch

Signs of complete blockade of the left bundle branch:

The QRS complex is deformed and widened (more than 0.12 s);

Offset of the S-T segment from the isoline;

Negative T wave in leads V5 and V6;

Expansion and splitting of the QRS complex in leads V5 and V6 in the form of RR;

Deformation and expansion of the QRS in leads V1 and V2 in the form of rS.

These types of blockades occur in cases of heart injury, acute myocardial infarction, atherosclerotic and myocardial cardiosclerosis, and with the improper use of a number of medications (cardiac glycosides, novocainamide).

Patients with intraventricular block do not need special therapy. They are hospitalized for treatment of the disease that caused the blockade.

7.2.4. Wolff-Parkinson-White syndrome

This syndrome (WPW) was first described by the above-mentioned authors in 1930 as a form of supraventricular tachycardia that is observed in young healthy people (“functional bundle branch block”).

It has now been established that in the body, sometimes, in addition to the normal path of impulse conduction from the sinus node to the ventricles, there are additional bundles (Kent, James and Mahaim). Along these pathways, excitation reaches the ventricles of the heart faster.

There are several types of WPW syndrome. If excitation enters the left ventricle earlier, then WPW syndrome type A is recorded on the ECG. With type B, excitation enters the right ventricle earlier.

Signs of WPW syndrome type A:

The delta wave on the QRS complex is positive in the right precordial leads and negative in the left (the result of premature excitation of part of the ventricle);

The direction of the main teeth in the chest leads is approximately the same as with blockade of the left bundle branch.

Signs of WPW syndrome type B:

Shortened (less than 0.11 s) P-Q interval;

The QRS complex is widened (more than 0.12 s) and deformed;

Negative delta wave for the right chest leads, positive for the left ones;

The direction of the main teeth in the chest leads is approximately the same as with blockade of the right bundle branch.

It is possible to register a sharply shortened P-Q interval with an undeformed QRS complex and the absence of a delta wave (Lown-Ganong-Levin syndrome).

Additional bundles are inherited. In approximately 30–60% of cases they do not manifest themselves. Some people may develop paroxysms of tachyarrhythmias. In case of arrhythmia health care turns out to be in accordance with the general rules.

7.2.5. Early ventricular repolarization

This phenomenon occurs in 20% of patients with cardiovascular pathology (most often found in patients with supraventricular heart rhythm disturbances).

This is not a disease, but patients with cardiovascular disease who experience this syndrome, are 2–4 times more likely to suffer from rhythm and conduction disorders.

Signs of early ventricular repolarization (Fig. 11) include:

ST segment elevation;

Late delta wave (notch on the descending part of the R wave);

High amplitude teeth;

Double-humped P wave of normal duration and amplitude;

Shortening of PR and QT intervals;

A rapid and sharp increase in the amplitude of the R wave in the chest leads.

Rice. 11. ECG for early ventricular repolarization syndrome

7.2.6. Cardiac ischemia

In coronary heart disease (CHD), the blood supply to the myocardium is impaired. On early stages There may be no changes in the electrocardiogram; in the later stages they are very noticeable.

With the development of myocardial dystrophy, the T wave changes and signs of diffuse changes in the myocardium appear.

These include:

Reduced amplitude of the R wave;

S-T segment depression;

Biphasic, moderately widened and flat T wave in almost all leads.

IHD occurs in patients with myocarditis of various origins, and dystrophic changes myocardium and atherosclerotic cardiosclerosis.

7.2.7. Angina pectoris

With the development of an attack of angina, the ECG can reveal a displacement of the S-T segment and changes in the T wave in those leads that are located above the area with impaired blood supply (Fig. 12).

Rice. 12. ECG for angina pectoris (during an attack)

The causes of angina are hypercholesterolemia, dyslipidemia. In addition, arterial hypertension, diabetes mellitus, psycho-emotional overload, fear, and obesity can trigger the development of an attack.

Depending on which layer of the heart muscle ischemia occurs, there are:

Subendocardial ischemia (above the ischemic area S-T offset below the isoline, the T wave is positive, large amplitude);

Subepicardial ischemia (rise of the S-T segment above the isoline, T negative).

The occurrence of angina is accompanied by the appearance of typical chest pain, usually provoked physical activity. This pain is pressing in nature, lasts several minutes and goes away after taking nitroglycerin. If the pain lasts more than 30 minutes and is not relieved by taking nitro drugs, it is highly likely to assume acute focal changes.

Urgent Care for angina pectoris is to relieve pain and prevent recurrent attacks.

Analgesics (from analgin to promedol), nitro drugs (nitroglycerin, sustak, nitrong, monocinque, etc.), as well as validol and diphenhydramine, seduxen are prescribed. If necessary, oxygen inhalation is carried out.

7.2.8. Myocardial infarction

Myocardial infarction is the development of necrosis of the heart muscle as a result of prolonged circulatory disorders in the ischemic area of ​​the myocardium.

In more than 90% of cases, the diagnosis is determined using an ECG. In addition, a cardiogram allows you to determine the stage of a heart attack, find out its location and type.

An unconditional sign of a heart attack is the appearance on the ECG of a pathological Q wave, which is characterized by excessive width (more than 0.03 s) and greater depth (a third of the R wave).

Possible options: QS, QrS. An S-T shift (Fig. 13) and T wave inversion are observed.

Rice. 13. ECG for anterolateral myocardial infarction (acute stage). There are cicatricial changes in the posteroinferior parts of the left ventricle

Sometimes an S-T displacement occurs without the presence of a pathological Q wave (small-focal myocardial infarction). Signs of a heart attack:

Pathological Q wave in leads located above the infarction area;

Displacement of the S-T segment by an arc upward (lifting) relative to the isoline in the leads located above the infarction area;

Discordant displacement below the S-T segment isoline in leads opposite the area of ​​infarction;

Negative T wave in leads located above the infarction area.

As the disease progresses, the ECG changes. This relationship is explained by the stages of changes during a heart attack.

There are four stages in the development of myocardial infarction:

Acute;

Subacute;

Scarring stage.

The most acute stage (Fig. 14) lasts several hours. At this time, the S-T segment rises sharply in the corresponding leads on the ECG, merging with the T wave.

Rice. 14. Sequence of ECG changes during myocardial infarction: 1 – Q-infarction; 2 – not Q-infarction; A – the most acute stage; B – acute stage; B – subacute stage; D – scar stage (post-infarction cardiosclerosis)

In the acute stage, a zone of necrosis forms and a pathological Q wave appears. The R amplitude decreases, the S-T segment remains elevated, and the T wave becomes negative. The duration of the acute stage is on average about 1–2 weeks.

The subacute stage of infarction lasts for 1–3 months and is characterized by a cicatricial organization of the necrosis focus. On the ECG at this time there is a gradual return of the S-T segment to the isoline, the Q wave decreases, and the R amplitude, on the contrary, increases.

The T wave remains negative.

The scarring stage can last for several years. At this time, the organization of scar tissue occurs. On the ECG, the Q wave decreases or disappears completely, S-T is located on the isoline, negative T gradually becomes isoelectric, and then positive.

This phasing is often called the natural dynamics of the ECG during myocardial infarction.

A heart attack can be localized in any part of the heart, but most often occurs in the left ventricle.

Depending on the location, a distinction is made between anterior lateral and rear walls left ventricle. The localization and extent of changes are revealed by analyzing ECG changes in the corresponding leads (Table 6).

Table 6. Localization of myocardial infarction

Great difficulties arise in diagnosis re-infarction, when new changes are superimposed on an already changed ECG. Dynamic monitoring with recording of a cardiogram at short intervals helps.

A typical heart attack is characterized by burning, severe chest pain that does not go away after taking nitroglycerin.

There are also atypical forms of heart attack:

Abdominal (pain in the heart and stomach);

Asthmatic (cardiac pain and cardiac asthma or pulmonary edema);

Arrhythmic (cardiac pain and rhythm disturbances);

Collaptoid (cardiac pain and a sharp drop in blood pressure with profuse sweating);

Painless.

Treating a heart attack is an extremely difficult task. As a rule, the more difficult it becomes, the more widespread the lesion is. At the same time, according to the apt remark of one of the Russian zemstvo doctors, sometimes the treatment of an extremely severe heart attack goes unexpectedly smoothly, and sometimes an uncomplicated, simple micro-infarction makes the doctor sign of impotence.

Emergency care consists of relieving pain (for this purpose, narcotic and other analgesics are used), also eliminating fears and psycho-emotional arousal with the help of sedatives, reducing the area of ​​the heart attack (using heparin), and sequentially eliminating other symptoms depending on the degree of their danger.

After finishing inpatient treatment Patients who have had a heart attack are sent to a sanatorium for rehabilitation.

The final stage is long-term observation in a local clinic.

7.2.9. Syndromes due to electrolyte disturbances

Certain ECG changes make it possible to judge the dynamics of electrolyte content in the myocardium.

To be fair, it should be said that there is not always a clear correlation between the level of electrolytes in the blood and the content of electrolytes in the myocardium.

Nevertheless, electrolyte disturbances detected by ECG serve as a significant aid to the doctor in the process of diagnostic search, as well as in choosing the correct treatment.

The most well studied changes in the ECG are disturbances in potassium and calcium metabolism (Fig. 15).

Rice. 15. ECG diagnosis of electrolyte disorders (A. S. Vorobyov, 2003): 1 – normal; 2 – hypokalemia; 3 – hyperkalemia; 4 – hypocalcemia; 5 – hypercalcemia

7.2.9.1. Hyperkalemia

Signs of hyperkalemia:

Tall, pointed T wave;

Shortening QT interval;

Decreased R amplitude.

With severe hyperkalemia, intraventricular conduction disturbances are observed.

Hyperkalemia occurs in diabetes (acidosis), chronic renal failure, severe injuries with crushing muscle tissue, adrenal insufficiency, and other diseases.

7.2.9.2. Hypokalemia

Signs of hypokalemia:

Decreased S-T segment downwards;

Negative or biphasic T;

The appearance of U.

With severe hypokalemia, atrial and ventricular extrasystoles and intraventricular conduction disturbances appear.

Hypokalemia occurs when there is a loss of potassium salts in patients with severe vomiting, diarrhea, after prolonged use of diuretics, steroid hormones, for a number of endocrine diseases.

Treatment consists of replenishing potassium deficiency in the body.

7.2.9.3. Hypercalcemia

Signs of hypercalcemia:

Shortening of the Q-T interval;

Shortening of the S-T segment;

Expansion of the ventricular complex;

Rhythm disturbances with a significant increase in calcium.

Hypercalcemia is observed with hyperparathyroidism, bone destruction by tumors, hypervitaminosis D and excessive administration of potassium salts.

7.2.9.4. Hypocalcemia

Signs of hypocalcemia:

Increasing the duration of the QT interval;

Lengthening the S-T segment;

Decreased T amplitude.

Hypocalcemia occurs when the function of the parathyroid glands decreases, in patients with chronic renal failure, with severe pancreatitis and hypovitaminosis D.

7.2.9.5. Glycoside intoxication

Cardiac glycosides have long been successfully used in the treatment of heart failure. These tools are irreplaceable. Their intake helps to reduce heart rate (heart rate) and more vigorously expel blood during systole. As a result, hemodynamic parameters improve and manifestations of circulatory failure decrease.

In case of an overdose of glycosides, characteristic ECG signs appear (Fig. 16), which, depending on the severity of intoxication, require either dose adjustment or discontinuation of the drug. Patients with glycoside intoxication may experience nausea, vomiting, and interruptions in heart function.

Rice. 16. ECG in case of overdose of cardiac glycosides

Signs of glycoside intoxication:

Decreased heart rate;

Shortening of electrical systole;

Decreased S-T segment downwards;

Negative T wave;

Ventricular extrasystoles.

Severe intoxication with glycosides requires discontinuation of the drug and the prescription of potassium supplements, lidocaine and beta blockers.

Decoding an ECG is the job of a knowledgeable doctor. With this method functional diagnostics estimated:

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

However, modern patients often have access to their medical documents, in particular, to electrocardiography films on which medical reports are written. With their diversity, these records can reach even the most balanced but ignorant person. After all, the patient often does not know for certain how dangerous to life and health is what is written on the back of the ECG film by hand 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 not a single serious diagnosis (myocardial infarction, acute rhythm disturbances), a functional diagnostician will not let a patient leave the office, but, at a minimum, will send him for a consultation with a fellow specialist right there. About the rest of the “open secrets” in this article. In all unclear cases of pathological changes in the ECG, ECG monitoring, 24-hour monitoring (Holter), ECHO cardioscopy (ultrasound of the heart) and stress tests (treadmill, bicycle ergometry) are prescribed.

Numbers and Latin letters in ECG interpretation

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

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

QRS – (0.06-0.1s) -ventricular complex

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

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

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

Heart Rate Description Options

Sinus rhythm

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

Sinus arrhythmia

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

Sinus bradycardia

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

Sinus tachycardia

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

Extarsystole

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

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

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

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

• Class 1 - single rare extrasystoles with a frequency of up to 60 per hour, emanating from one focus (monotopic)
• 2 – frequent monotopic more than 5 per minute
• 3 – frequent polymorphic ( 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 drug treatment. In general, if there are less than 200 ventricular extrasystoles per day, they should be classified as functional and not worry about them. For more frequent cases, ECHO CS is indicated, and sometimes cardiac MRI is indicated. It is not the extrasystole that is treated, but the disease that leads to it.

Paroxysmal tachycardia

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

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

WPW syndrome

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

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

CLC – syndrome (Clerk-Levi-Christesco)

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

Atrial fibrillation

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

Atrial fibrillation

Atrial fibrillation

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

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

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

An attack of atrial fibrillation is difficult to miss.

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

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

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

Examples of recordings on ECG films:

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

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

Atrial flutter

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

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

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

Conduction disorders

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

Sinoatrial blockade

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

Atrioventricular block (AV block)

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

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

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

Impaired conduction within the ventricles

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

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

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

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

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

Myocardial hypertrophy

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

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

Changes in myocardial contractility and nutrition

Early ventricular repolarization syndrome

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

Moderate or severe diffuse changes in the myocardium

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

Nonspecific ST changes

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

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

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

Advanced heart attack

It is usually described:

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

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

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