Electrocardiograph with ecg decoding. Deciphering the ecg cardiogram of the heart

Electrocardiography is a method for diagnosing the state of the myocardium. This article will focus on the ECG norms in children, adults and women during pregnancy. In addition, the reader will learn about what cardiography is, how an ECG is done, what is the decoding of a cardiogram.

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Electrocardiography is a method used to record the electrical currents that occur when the heart muscle contracts and relaxes. For the study, an electrocardiograph is used. With the help of this device, it is possible to fix the electrical impulses that come from the heart and convert them into a graphic pattern. This image is called an electrocardiogram.

Electrocardiography reveals abnormalities in the work of the heart, malfunctions in the functioning of the myocardium. In addition, after deciphering the results of the electrocardiogram, some non-cardiac diseases can be detected.

How does an electrocardiograph work?

The electrocardiograph consists of a galvanometer, amplifiers and a recorder. Weak electrical impulses that originate in the heart are read by electrodes and then amplified. Then the galvanometer receives data on the nature of the pulses and transmits them to the registrar. In the registrar, graphic images are applied to special paper. Graphs are called cardiograms.

How is an EKG done?

Do electrocardiography according to established rules. The procedure for taking an ECG is shown below:

A person removes metal jewelry, removes clothes from the shins and from the upper part of the body, after which he assumes a horizontal position.
The doctor processes the contact points of the electrodes with the skin, after which he applies the electrodes to certain places on the body. Further, fixes the electrodes on the body with clips, suction cups and bracelets.
The doctor attaches the electrodes to the cardiograph, after which the impulses are registered.
A cardiogram is recorded, which is the result of an electrocardiogram.

Separately, it should be said about the leads used in the ECG. Leads use the following:

3 standard leads: one of them is located between the right and left hands, the second is between the left foot and the right hand, the third is between the left foot and the left hand.
3 limb leads with enhanced character.
6 leads located on the chest.

In addition, if necessary, additional leads can be used.

After the cardiogram is recorded, it is necessary to decrypt it. This will be discussed further.

Deciphering the cardiogram

Conclusions about diseases are made on the basis of the parameters of the heart, obtained after deciphering the cardiogram. The following is the procedure for decoding the ECG:

The heart rhythm and myocardial conduction are analyzed. To do this, the regularity of contractions of the heart muscle and the frequency of contractions of the myocardium are evaluated, and the source of excitation is determined.
The regularity of heart contractions is determined as follows: R-R intervals are measured between successive heart cycles. If the measured R-R intervals are the same, then a conclusion is made about the regularity of contractions of the heart muscle. If the duration of the R-R intervals is different, then a conclusion is made about the irregularity of heart contractions. If a person has irregular contractions of the myocardium, then they conclude that there is an arrhythmia.
The heart rate is determined by a certain formula. If the heart rate in a person exceeds the norm, then they conclude that there is tachycardia, if the person has a heart rate below the norm, then they conclude that there is bradycardia.
The point from which excitation emanates is determined as follows: the movement of contraction in the atrial cavities is estimated and the relationship of the R waves to the ventricles is established (according to the QRS complex). The nature of the heart rhythm depends on the source that is the cause of the excitation.

The following patterns of heart rhythms are observed:

The sinusoidal nature of the heart rhythm, in which the P waves in the second lead are positive and are in front of the ventricular QRS complex, and the P waves in the same lead have an indistinguishable shape.
Atrial rhythm of the nature of the heart, in which the P waves in the second and third leads are negative and are in front of the unchanged QRS complexes.
The ventricular nature of the heart rhythm, in which there is a deformation of the QRS complexes and a loss of communication between the QRS (complex) and the P waves.

The conduction of the heart is determined as follows:

Measurements of P-wave length, PQ interval length, and QRS complex are evaluated. Exceeding the normal duration of the PQ interval indicates too low conduction velocity in the corresponding cardiac conduction section.
Myocardial rotations around the longitudinal, transverse, anterior and posterior axes are analyzed. To do this, the position of the electrical axis of the heart in a common plane is estimated, after which the presence of turns of the heart along one axis or another is established.
The atrial P wave is analyzed. For this, the amplitude of the P bison is assessed, the duration of the P wave is measured. After that, the shape and polarity of the P wave are determined.
The ventricular complex is analyzed - For this, the QRS complex, the RS-T segment, the QT interval, the T wave are evaluated.

During the assessment of the QRS complex, do the following: determine the characteristics of the Q, S and R waves, compare the amplitude values of the Q, S and R waves in a similar lead and the amplitude values of the R/R waves in different leads.

At the time of evaluation of the RS-T segment, the nature of the displacement of the RS-T segment is determined. The offset can be horizontal, skew-down and skew-up.

For the period of analysis of the T wave, the nature of the polarity, amplitude and shape are determined. The QT interval is measured by the time from the beginning of the QRT complex to the end of the T wave. When assessing the QT interval, do the following: analyze the interval from the starting point of the QRS complex to the end point of the T wave. To calculate the QT interval, the Bezzet formula is used: the QT interval is equal to the product of the R-R interval and a constant coefficient.

The coefficient for QT depends on gender. For men, the constant coefficient is 0.37, and for women it is 0.4.

A conclusion is made and the results are summarized.

In conclusion, the ECG specialist draws conclusions about the frequency of the contractile function of the myocardium and heart muscle, as well as the source of excitation and the nature of the heart rhythm and other indicators. In addition, an example of the description and characteristics of the P wave, QRS complex, RS-T segment, QT interval, T wave is given.

Based on the conclusion, it is concluded that a person has heart disease or other ailments of internal organs.

Electrocardiogram norms

The table with ECG results has a clear view, consisting of rows and columns. In the 1st column, the lines list: heart rate, beat rate examples, QT intervals, examples of axis displacement characteristics, P-wave readings, PQ readings, QRS reading examples. ECG is carried out equally in adults, children and pregnant women, but the norm is different.

The ecg norm in adults is presented below:

heart rate in a healthy adult: sinus;
P-wave index in a healthy adult: 0.1;
the frequency of contractions of the heart muscle in a healthy adult: 60 beats per minute;
QRS rate in a healthy adult: from 0.06 to 0.1;
QT score in a healthy adult: 0.4 or less;
RR in a healthy adult: 0.6.

In the case of observation of deviations from the norm in an adult, a conclusion is made about the presence of the disease.

The norm of cardiogram indicators in children is presented below:

P-wave score in a healthy child: 0.1 or less;
heart rate in a healthy child: 110 beats per minute or less in children under 3 years old, 100 beats per minute or less in children under 5 years old, no more than 90 beats per minute in children in adolescence;
QRS index in all children: from 0.06 to 0.1;
QT score in all children: 0.4 or less;
PQ in all children: if the child is under 14 years old, then the example PQ is 0.16, if the child is from 14 to 17 years old, then the PQ is 0.18, after 17 years the normal PQ is 0.2.

If in children, when deciphering the ECG, any deviations from the norm were found, then treatment should not be started immediately. Some disorders in the work of the heart disappear in children with age.

But in children, heart disease can be congenital. It is possible to determine whether a newborn child will have a heart pathology even at the stage of fetal development. For this purpose, electrocardiography is done to women during pregnancy.

The norm of electrocardiogram indicators in women during pregnancy is presented below:

heart rate in a healthy adult child: sinus;
P wave score in all healthy women during pregnancy: 0.1 or less;
the frequency of contractions of the heart muscle in all healthy women during pregnancy: 110 or less beats per minute in children under 3 years old, 100 or less beats per minute in children under 5 years old, no more than 90 beats per minute in children in adolescence;
QRS rate in all expectant mothers during pregnancy: from 0.06 to 0.1;
QT score in all expectant mothers during pregnancy: 0.4 or less;
PQ index for all expectant mothers during pregnancy: 0.2.

It is worth noting that in different periods of pregnancy, ECG indicators may differ slightly. In addition, it should be noted that ECG during pregnancy is safe for both the woman and the developing fetus.

Additionally

It is worth saying that under certain circumstances, electrocardiography can give an inaccurate picture of a person's health status.

If, for example, a person subjected himself to heavy physical exertion before an ECG, then an erroneous picture may be revealed when deciphering the cardiogram.

This is explained by the fact that during physical exertion the heart begins to work differently than at rest. During physical exertion, the heart rate increases, some changes in the rhythm of the myocardium may be observed, which is not observed at rest.

It should be noted that the work of the myocardium is affected not only by physical loads, but also by emotional loads. Emotional loads, like physical loads, disrupt the normal course of myocardial work.

At rest, the heart rhythm normalizes, the heartbeat evens out, therefore, before electrocardiography, it is necessary to be at rest for at least 15 minutes.

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

How to decipher the cardiogram of the heart: general principles

The main elements of the electrocardiographic curve are:

ECG analysis

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

It determines whether the heart beats rhythmically, that is, whether the rhythm is correct. To do this, he measures the intervals between the R waves, they should be the same everywhere, if not, this is already the wrong rhythm.
Calculates the rate at which the heart beats (HR). This is easy to do, knowing the ECG recording speed and counting the number of millimeter cells between adjacent R waves. Normally, the heart rate should not go beyond 60-90 beats. in a minute.
According to specific features (mainly by the P wave), it determines the source of excitation in the heart. Normally, this is the sinus node, that is, in a healthy person, sinus rhythm is considered normal. Atrial, atrioventricular and ventricular rhythms indicate pathology.
Assesses the conduction of the heart by the duration of the teeth and segments. For each of them there are indicators of the norm.
Determines the electrical axis of the heart (EOS). For very thin people, a more vertical position of the EOS is characteristic, for full people it is more horizontal. With pathology, the axis shifts sharply to the right or left.
Analyzes teeth, segments and intervals in detail. The doctor writes down their duration on the cardiogram by hand in seconds (this is an incomprehensible set of Latin letters and numbers on the ECG). Modern electrocardiographs automatically analyze these indicators and immediately provide measurement results, which simplifies the work of the doctor.
Gives a conclusion. It necessarily indicates the correctness of the rhythm, the source of excitation, heart rate, characterizes the EOS, and also highlights specific pathological syndromes (rhythm disturbance, conduction disturbance, the presence of overload of individual parts of the heart and myocardial damage), if any.

Examples of electrocardiographic findings

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

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

In addition, in conclusion, we can talk about a non-specific change in the ST-T interval. This means that the changes are not indicative and it is impossible to determine their cause only by the ECG. Another fairly common condition that can be diagnosed by a cardiogram is a violation of repolarization processes, that is, a violation of the recovery of the ventricular myocardium after excitation. This change can be caused by both severe heart disease and chronic infections, hormonal imbalances and other causes that the doctor will subsequently look for.

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

Deciphering the ECG in children

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

Also, sinus or respiratory arrhythmia (increased heart rate on inspiration and decrease on expiration) can be recorded in babies without any pathology. In addition, the characteristics of some teeth and intervals differ from those of adults. For example, a child may have an incomplete blockade of part of the conduction system of the heart - the right leg of the bundle of His. All these features are taken into account by pediatric cardiologists when they make a conclusion on the ECG.

Features of the ECG during pregnancy

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

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

Deciphering the ECG, the norm of indicators

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

heart rhythm - the state of the generators of electrical impulses and the state of the heart system that conducts these impulses
the state of the heart muscle itself (myocardium). the presence or absence of its inflammation, damage, thickening, oxygen starvation, electrolyte imbalance

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

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

Numbers and Latin letters in ECG decoding

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

P - (0.1s) height 0.25-2.5 mm describes atrial contractions. Can talk about their hypertrophy.

QRS - (0.06-0.1s) - ventricular complex

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

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

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

Options for describing the heart rate

Sinus rhythm

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

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

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

Sinus tachycardia

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

Extrasystole

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

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

Single extrasystoles are most often rare (less than 5 per hour). They are usually functional and do not interfere with the normal blood supply.
Paired extrasystoles of two accompany a certain number of normal contractions. Such a rhythm disturbance often indicates pathology and requires additional examination (Holter monitoring).
Allorhythmias are more complex types of extrasystoles. If every second contraction is an extrasystole, it is bigymenia, if every third is trigynemia, and every fourth is quadrihymenia.

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

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

The higher the class, the more serious the violations, although today even grades 3 and 4 do not always require medical treatment. In general, if there are less than 200 ventricular extrasystoles per day, they should be classified as functional and not worry about them. With more frequent, ECHO of the COP is indicated, sometimes - MRI of the heart. They do not treat extrasystole, but the disease that leads to it.

Paroxysmal tachycardia

In general, paroxysm is an attack. Paroxysmal acceleration of the rhythm can last from several minutes to several days. In this case, the intervals between heartbeats will be the same, and the rhythm will increase over 100 per minute (on average from 120 to 250). There are supraventricular and ventricular forms of tachycardia. The basis of this pathology is the abnormal circulation of an electrical impulse in the conduction system of the heart. Such a pathology is subject to treatment. From home remedies to eliminate an attack:

breath holding
increased forced cough
face immersion in cold water

WPW syndrome

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

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

CLC - Syndrome (Clerk-Levy-Christesco)

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

Atrial fibrillation

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

Atrial fibrillation

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

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

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

An attack of atrial fibrillation is difficult to miss.

It usually starts with a strong heartbeat.
It develops as a series of absolutely non-rhythmic heartbeats with a high or normal frequency.
The condition is accompanied by weakness, sweating, dizziness.
The fear of death is very pronounced.
There may be shortness of breath, general arousal.
Sometimes there is a loss of consciousness.
The attack ends with the normalization of the rhythm and the urge to urinate, in which a large amount of urine leaves.

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

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

Examples of recordings on ECG films:

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

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

atrial flutter

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

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

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

Conduction disorders

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

Sinoatrial blockade

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

Atrioventricular block (AV block)

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

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

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

Conduction disturbance within the ventricles

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

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

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

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

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

Myocardial hypertrophy

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

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

Changes in myocardial contractility and nutrition

Syndrome of early repolarization of the ventricles

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

Moderate or severe diffuse changes in the myocardium

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

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

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

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

Developed heart attack

It is usually described as:

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

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

How to decipher the ECG of the heart?

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

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

Decryption principles

Each curve on the cardiogram graph has its own elements:

Teeth, which are bulges directed down or up. All of them are denoted by Latin capital letters. "P" shows the work of the heart atria. "T" is the restorative capacity of the myocardium.
Segments are the distance between several ascending or descending teeth in the neighborhood. Doctors are especially interested in indicators of such segments as ST, as well as PQ.
An interval is a gap that includes both a segment and a tooth.

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

How are the results analyzed?

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

The correct rhythm is determined by the intervals between the "R"-teeth. They must be equal. Otherwise, it can be concluded that the heart rhythm is incorrect.
With the help of an ECG, you can determine the heart rate. To do this, you need to know the speed at which the indicators were recorded. Additionally, you will also need to count the number of cells between the two R waves. The norm is from 60 to 90 beats per minute.
The source of excitation in the heart muscle is determined by a number of specific features. This will be told, among other things, by the evaluation of the parameters of the “P” wave. The norm implies that the source is the sinus node. Therefore, a healthy person always has a sinus rhythm. If there is a ventricular, atrial or any other rhythm, then this indicates the presence of pathology.
The specialist evaluates the conduction of the heart. This happens according to the duration of each segment and tooth.
The electrical axis of the heart, if it shifts to the left or right sharply enough, may also indicate problems with the cardiovascular system.
Each tooth, interval and segment is analyzed individually and in detail. Modern ECG devices immediately automatically issue indicators of all measurements. This greatly simplifies the work of the doctor.
Finally, the specialist makes a conclusion. It indicates the decoding of the cardiogram. If any pathological syndromes were found, they must be indicated there.

Normal indicators of adults

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

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

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

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

What do teeth mean?

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

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

Normal pediatric electrocardiogram readings

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

The heart rate of babies under 3 years old is about 110 pulsations per minute, and at the age of 3-5 years - 100 beats. This indicator in adolescents is already lower - 60-90 pulsations.
The norm of QRS readings is 0.6-0.1 s.
The P wave should normally not be higher than 0.1 s.
The electrical axis of the heart in children should remain unchanged.
The rhythm is only sinus.
On the ECG, the Q-T interval e can exceed 0.4 s, and P-Q should be 0.2 s.

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

Why are the scores different?

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

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

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

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

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

Learning to read an electrocardiogram on your own

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

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

Meaning of cells (cells)

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

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

teeth

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

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

All ECG teeth have their own reading characteristics.

Prong R

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

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

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

R wave

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

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

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

300/number of large squares = heart rate.

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

300/4=75 heart beats per minute.

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

PQ wave interval

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

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

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

Interval between QT waves

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

ST interval

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

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

Norm

The decoding of the cardiogram normally should look like this:

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

ECG in pathologies: sinus arrhythmia

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

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

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

The manifestation of a heart attack on the ECG

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

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

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

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

Ischemia

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

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

Changes in the ventricles

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

Holter method

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

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

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

ECG decoding schemes

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

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

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

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

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

cardiac conduction

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

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

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

All kinds of pathologies of the cardiovascular system are faced by representatives of both sexes and in any age category. Timely diagnosis greatly facilitates the selection of appropriate treatment and the process of stabilizing the condition of patients.

For many years, the electrocardiogram has been the most accessible, but at the same time quite informative method of examining the heart. The implementation of such a procedure involves the registration of cardiac electrical impulses and their graphic recording in the form of teeth on a special paper film. The obtained data allow not only to evaluate the transmission of electrical impulses in the heart, but also to diagnose problems in the structure of the heart muscle.

ECG allows diagnosing from minor to critical pathological conditions of the heart. However, on their own without special professional training, a person will not be able to fully decipher the electrocardiogram. Although he can draw certain conclusions, knowing what a normal ECG looks like.

Basic elements of an ECG

The biopotentials of the heart are recorded by fixing the electrodes of the electrocardiograph on the upper and lower extremities, as well as on the chest on the left. Thus, it turns out to collect all directions of electrogenesis in the human body. The recording electrodes are placed on different parts of the body and this is what affects the leads. They are standard, unipolar and chest.

Deciphering the ECG in adults is based on the study of all positive and negative peaks of the cardiogram, their duration, contiguity and other parameters. In the process, the following main elements of the ECG are analyzed:

the response of the heart to contractions in the form of peaks (teeth);
isolines between two adjacent teeth (segments);
complex of teeth + segment (intervals).

After the passage of an electrical impulse through the conduction system of the heart, the cardiogram displays rises and falls of a curved line, which are denoted by capital letters of the Latin alphabet - P, Q, R, S and T. The P wave occurs when the atria are excited, the QRS complex characterizes the excitation of the myocardial ventricles, the wave T indicates the process of extinction of excitation and restoration of the initial state.

The interval on the electrocardiogram is measured in seconds. It indicates the passage of an impulse through certain parts of the heart. For diagnostic purposes, special attention is paid to the PQ interval (characterizes the time of excitation to the ventricles) and QT (does not have constant values and depends on the heart rate).

An ECG segment is a segment of an isoline located between two adjacent peaks. In the diagnosis, the PQ segments (the time from the end of the P wave to the beginning of the Q wave) and ST segments (normally located on the isoelectric line or slightly deviate from it) turn out to be informative. In the conclusion of a doctor, not only uppercase, but also lowercase letters of the Latin alphabet can also be found. They are also intended to indicate the main elements, but only in the case when the peak does not exceed 5 mm in length.

If the ECG is recorded at a speed of 50 mm / s, then each small cell (1 mm) on the tape is equal to 0.02 seconds.

Additional Nebu leads can be used to obtain more accurate information about the state of the myocardium.

Decryption plan

Deciphering the cardiogram of the heart must necessarily include the following parameters:

the total direction of the electrical impulse;
characteristics of the heart rhythm and impulse propagation;
frequency and regularity of heart contractions;
determination of the electrical impulse generator;
amplitude of the P wave, PQ interval and QRST complex;
RST isoline and T wave parameters;
QT interval parameters.

During the examination of people with problems with the heart and blood vessels, the following pathologies can be detected: bradycardia, tachycardia, arrhythmia, blockade, ventricular or atrial overload, and damage to the myocardial structure itself.

In the description of the ECG conclusion, the following parameters must be indicated:

rhythmic heartbeats;
estimation of distances between peaks;
the number of heartbeats per unit of time;
EOS position (horizontal/vertical).

Sample conclusion: “Sinus rhythm with 65 heartbeats per minute. EOS has a normal position. No pathological abnormalities were found." And maybe in conclusion, not everything is so smooth: “Sinus rhythm with severe tachycardia (100 contractions). Supraventricular untimely depolarization and contraction of the heart or its individual chambers. Incomplete blockade of PNPG. In the myocardium, a moderate metabolic disorder is observed.

At the beginning of each electrocardiogram tape, a calibration signal must be present, which, when a standard voltage of 1 millivolt is applied, should give a deviation of 10 mm. If it is absent, then the ECG recording is considered incorrect.

As a rule, on the ECG, each lead (12 pieces) is given a specific area

Rhythm of contractions

The main pacemaker of the first order is considered to be the sinus node or the Keith-Flak node. But in a number of pathological conditions, the sinus node loses its functionality and then it begins to be replaced by the underlying structures.

Possible variants of electrocardiographic rhythms:

With sinus rhythm on the cardiogram (the electrode of the left leg (+) and the electrode of the right hand (-), each QRS complex is preceded by a P wave going up from the isoline. The amplitude of all peaks is the same.
Atrial rhythm occurs when the function of the sinus node weakens, and impulses begin to come from the lower atrial centers. The P wave still occurs before each QRS complex, but in leads with electrodes connected to the left leg (+) and right arm (-), it goes down from the isoline.
The rhythm of the atrioventricular connection. In this case, impulses propagate retrograde to the atria and antegrade to the ventricles. Such a rhythm is characterized by the complete absence of P waves on cardiograms, or they appear after the QRS complex.
The ventricular (indioventricular) rhythm is characterized by the presence of dilated and deformed QRS complexes. And there is also no classic relationship between the P waves and the QRS complex. Heart rate in this case can be reduced to 40.

If any other structure becomes the pacemaker, then the electrical impulses of the heart, which are cyclical, get confused, and arrhythmia occurs against this background.

Multiple repetition of the rhythm

Heart rate cycling is an ECG indicator that is assessed by comparing the duration of the wave-and-segment complex (R-R) between several successive cycles. The regular rhythm on the cardiogram of the heart looks like this - throughout the entire registration, the peaks have the same amplitude and are evenly distributed one after another. Assess the gap between the two positive teeth of the complex by measuring any gaps between them. The graph paper of the electrocardiograph helps a lot with this.

heart rate

The heart rate is calculated mathematically. On the tape with the cardiogram, large squares between the rises and falls of the curved line are clearly evident. They are counted and if the recording was carried out at a speed of 50 mm / s, then the number 600 is divided by their number. And if the speed was 25 mm / s, then 300 is substituted instead of 600.

If the heart rhythm is obviously wrong, then it is necessary to calculate the minimum and maximum number of contractions of the heart muscle. For this, the largest and smallest distance between the teeth that occur during atrial excitation are taken as a basis.

Total EMF vector

On the ECG of the heart, the electrical axis is designated - ∠ α (alpha) and is the total vector of electromotive force (EMF) or ventricular depolarization. The total EMF vector may reflect a normal position, or it may be located vertically (in thin patients) or horizontally (in stocky ones).

EOS within the normal range is in the range from +30° to +69°, in a vertical position - from +70° to +90°, and in a horizontal position - from 0° to +29°. With a significant deviation of the axis to the right, indicators from +91° to +180° are observed. With a pronounced shift to the left - from 0 ° to -90 °. A persistent increase in blood pressure will mix the total EMF vector to the right, and with heart blockades, both right-sided and left-sided shifts can be observed.

The table shows the ECG norm in adults

The main criteria of the norm

If the decoding of the ECG in adults has normal values, then the following may be indicated in the conclusion:

The interval from the beginning of the P wave to the beginning of the ventricular QRS complex is 0.12 seconds.
The duration of intraventricular excitation (QRS complex) is 0.06 seconds.
The distance from the start of the QRS complex to the end of the T wave is 0.31 seconds.
The stable frequency of contractions of the heart muscle (RR interval) is 0.6.
The heart beats at a rate of 75 beats in 60 seconds.
Normal heart rhythm (impulse generated by the sinus node).
Normogram (normal position of the EOS).

The ECG of a healthy person implies the following norms: sinus heart rate, heart rate above 60, but below 90 beats per 60 seconds, the P peak is 0.1 second, the PQ interval is in the range of 0.12–0.2 seconds, the RS-T segment is on the isoline, the QT interval does not exceed 0.4 seconds.

ECG norms in children are practically no different from adults. However, in young patients, due to the physiological factor, the heart rate is higher than in older patients. In babies under 3 years old, the heart can make up to 100-110 beats per minute, which is considered quite normal. And already at the age of 3 to 5 years, this figure decreases by 10 units. As they grow older, the heart rate decreases and already in adolescents it is no different from adults.

Decryption steps

To determine the ECG is normal or not, such actions will help. Expand the tape with the ECG record and begin to carefully study the graphs. They are several parallel horizontal lines with positive and negative teeth. In some places, at the moment of interruption of the recording, there are no teeth at some intervals.

The cardiogram is performed in different leads, so each new segment has its own designation (I, II, III, AVL, VI). It is necessary to find the lead, in which the positive electrode is fixed on the left leg, and the negative and the highest peak in it on the right hand, and then measure the intervals between them and derive the average value of the indicator. This figure will come in handy in the further calculation of heart rate in 60 seconds.

Calculations should be carried out taking into account the dimensions of graph paper (1 large cell = 5 mm, 1 small cell or dot = 1 mm). To determine the characteristics of multiple repetitions of heart beats, the intervals between the R waves (identical or very different) should be assessed. Then you should sequentially evaluate and measure all the complexes of teeth and segments on the cardiogram.

And to understand whether they correspond to the norm, you can use special diagnostic tables. However, it should be remembered that a person without special education can only roughly evaluate the individual elements of the cardiogram and, using the tables, check their compliance with the norm. But only a certified specialist in cardiology can make a final conclusion on the ECG and prescribe adequate treatment.

Registration of an electrocardiogram is a method of studying electrical signals generated during the activity of the muscles of the heart. To record electrocardiogram data, 10 electrodes are used: 1 zero on the right leg, 3 standard ones from the extremities and 6 in the heart area.

The result of the removal of electrical indicators, the work of various departments of the body, is the creation of an electrocardiogram.

Its parameters are recorded on a special roll paper. Paper movement speed is available in 3 options:

25 mm.sec;
50 mm.sec;
100 mm.sec;

There are electronic sensors that can record ECG parameters on the hard drive of the system unit and, if necessary, display this data on a monitor or print it on the required paper formats.

Interpretation of the recorded electrocardiogram.

The specialist cardiologist gives the result of the analysis of the parameters of the electrocardiogram. The doctor deciphers the record by establishing the duration of the intervals between the various elements of the recorded indicators. An explanation of the features of the electrocardiogram contains many points:

Normal ECG.

Consideration of a standard cardiogram of the heart is represented by the following indicators:

Electrocardiogram in case of myocardial infarction.

Myocardial infarction occurs due to an exacerbation of coronary disease, when the internal cavity of the coronary artery of the heart muscle is significantly narrowed. If this violation is not eliminated within 15 - 20 minutes, the death of the muscle cells of the heart, which receive oxygen and nutrients from this artery, occurs. This circumstance creates significant disturbances in the functioning of the heart and is a severe and serious threat to life. In the event of a heart attack of the heart, an electrocardiogram will help identify the site of necrosis. The specified cardiogram contains markedly manifested deviations in the electrical signals of the heart muscle:

Heart rhythm disorder.

A disorder in the rhythm of contraction of the heart muscles is detected when shifts appear on the electrocardiogram:

Hypertrophy of the heart.

An increase in the volume of the heart muscles is an adaptation of the body to new conditions of functioning. The changes that appear on the electrocardiogram are determined by the high bioelectric force of a characteristic muscle area, the delay in the movement of bioelectric impulses in its thickness, and the appearance of signs of oxygen starvation.

Conclusion.

Electrocardiographic indicators of cardiac pathology are diverse. Reading them is a complex activity that requires special training and improvement of practical skills. A specialist characterizing an ECG needs to know the basic principles of the physiology of the heart, various versions of cardiograms. He needs to have skills in the ability to determine anomalies in the activity of the heart. Calculate the effect of drugs and other factors on the occurrence of differences in the structure of the waves and gaps of the ECG. Therefore, the interpretation of the electrocardiogram should be entrusted to a specialist who has encountered in his practice with various options for shortcomings in the work of the heart.