Indications of the cardiogram interpretation. Why do an ECG of the heart? Deciphering the analysis, norms, indications and contraindications

Electrocardiography is one of the most common and most informative methods for diagnosing a huge number of diseases. An ECG involves a graphical display of electrical potentials that are formed in a beating heart. The removal of indicators and their display is carried out by means of special devices - electrocardiographs, which are constantly being improved.

As a rule, during the study, 5 teeth are fixed: P, Q, R, S, T. At some points, it is possible to fix an inconspicuous U wave.

Electrocardiography allows you to identify the following indicators, as well as options for deviations from the reference values:

• Heart rate (pulse) and regularity of myocardial contractions (arrhythmias and extrasystoles can be detected);
• Violations in the heart muscle of an acute or chronic nature (in particular, with ischemia or infarction);
• metabolic disorders of the main compounds with electrolytic activity (K, Ca, Mg);
• violations of intracardiac conduction;
• hypertrophy of the heart (atria and ventricles).

Note:when used in parallel with a cardiophone, the electrocardiograph provides the ability to remotely determine some acute heart diseases (presence of ischemia or heart attacks).

ECG is the most important screening technique for detecting coronary artery disease. Valuable information is provided by electrocardiography with the so-called. "load tests".

In isolation or in combination with other diagnostic methods, ECG is often used in the study of cognitive (mental) processes.

Important:an electrocardiogram must be taken during the medical examination, regardless of age and general condition patient.

ECG: indications for holding

There are a number of pathologies of cardio-vascular system and other organs and systems in which an electrocardiographic study is prescribed. These include:

• angina;
• myocardial infarction;
• reactive arthritis;
• peri- and myocarditis;
• nodular periarteritis;
• arrhythmias;
• acute renal failure;
• diabetic nephropathy;
• scleroderma.

With hypertrophy of the right ventricle, the amplitude of the S wave in leads V1-V3 increases, which may be an indicator of symmetrical pathology from the left ventricle.

With left ventricular hypertrophy, the R wave is pronounced in the left chest leads and its depth is increased in leads V1-V2. The electrical axis is either horizontal or deviated to the left, but it can often correspond to the norm. The QRS complex in lead V6 has a qR or R shape.

Note:this pathology is often accompanied by secondary changes in the heart muscle (dystrophy).

Left atrial hypertrophy is characterized by a rather significant increase in the P wave (up to 0.11-0.14 s). It acquires a "double-humped" shape in the left chest leads and leads I and II. In rare clinical cases, there is some flattening of the tooth, and the duration of the internal deviation of P exceeds 0.06 s in leads I, II, V6. Among the most prognostic evidence of this pathology is an increase in the negative phase of the P wave in lead V1.

Hypertrophy of the right atrium is characterized by an increase in the amplitude of the P wave (over 1.8-2.5 mm) in leads II, III, aVF. This tooth acquires a characteristic pointed shape, and the electrical axis P is installed vertically or has some shift to the right.

Combined atrial hypertrophy is characterized by a parallel expansion of the P wave and an increase in its amplitude. In some clinical cases, changes such as sharpness of P in leads II, III, aVF and splitting of the apex in I, V5, V6 are noted. In lead V1, an increase in both phases of the P wave is occasionally recorded.

For heart defects formed during fetal development, a significant increase in the amplitude of the P wave in leads V1-V3 is more characteristic.

In patients with severe chronic cor pulmonale with emphysematous lung disease, as a rule, an S-type ECG is determined.

Important:combined hypertrophy of two ventricles at once is rarely determined by electrocardiography, especially if the hypertrophy is uniform. In this case, pathological signs tend to be mutually compensated, as it were.

With "syndrome of premature excitation of the ventricles" on the ECG, the width of the QRS complex increases and the R-R interval becomes shorter. The delta wave, which affects the increase in the QRS complex, is formed as a result of an early increase in the activity of sections of the heart muscle of the ventricles.

Blockades are caused by the termination of the conduction of an electrical impulse in one of the sections.

Violations of impulse conduction are manifested on the ECG by a change in the shape and an increase in the size of the P wave, and with intraventricular blockade - an increase in QRS. Atrioventricular blockade may be characterized by the loss of individual complexes, an increase in P-Q interval, and in the most severe cases - a complete lack of communication between QRS and P.

Important:sinoatrial blockade appears on the ECG as a rather bright picture; it is characterized by the complete absence of the PQRST complex.

In case of violations heart rate evaluation of electrocardiography data is carried out on the basis of analysis and comparison of intervals (inter- and intra-cycle) for 10-20 seconds or even longer.

An important diagnostic value in the diagnosis of arrhythmias is the direction and shape of the P wave, as well as the QRS complex.

Myocardial dystrophy

This pathology is visible only in some leads. It is manifested by changes in the T wave. As a rule, its pronounced inversion is observed. In some cases, a significant deviation from the normal RST line is recorded. Pronounced dystrophy of the heart muscle is often manifested by a pronounced decrease in the amplitude of the QRS and P waves.

If a patient develops an attack of angina pectoris, then a noticeable decrease (depression) in RST is recorded on the electrocardiogram, and in some cases, inversion of T. These changes on the ECG reflect ischemic processes in the intramural and subendocardial layers of the cardiac muscle of the left ventricle. These areas are the most demanding for blood supply.

Note:short-term rise of the RST segment is hallmark pathology known as Prinzmetal's angina.

Approximately 50% of patients in the intervals between angina attacks, changes in the ECG may not be recorded at all.

In this life-threatening condition, an electrocardiogram makes it possible to obtain information about the extent of the lesion, its exact location and depth. In addition, the ECG allows you to track the pathological process in dynamics.

Morphologically, it is customary to distinguish three zones:

• central (zone of necrotic changes in myocardial tissue);
• the zone of the expressed dystrophy of a cardiac muscle surrounding the center;
• peripheral zone of pronounced ischemic changes.

All changes that are reflected in the ECG dynamically change according to the stage of development of myocardial infarction.

Dishormonal myocardial dystrophy

Myocardial dystrophy, caused by a sharp change in the hormonal background of the patient, as a rule, is manifested by a change in the direction (inversions) of the T wave. Depressive changes in the RST complex are much less common.

Important: The severity of changes over time may vary. Pathological changes recorded on the ECG are only in rare cases associated with such clinical symptoms as pain in the area chest.

To distinguish manifestations of coronary artery disease from myocardial dystrophy against a background of hormonal imbalance, cardiologists practice tests using such pharmacological agents, as blockers of β-adrenergic receptors and potassium-containing drugs.

Changes in the electrocardiogram parameters against the background of the patient taking certain medications

Changes in the ECG picture can give the reception of the following drugs:

• drugs from the group of diuretics;
• agents related to cardiac glycosides;
• amiodarone;
• Quinidine.

In particular, if the patient takes digitalis preparations (glycosides) in the recommended doses, then the relief of tachycardia (rapid heartbeat) and a decrease in interval Q-T. "Smoothing" of the RST segment and shortening of T is also not excluded. An overdose of glycosides is manifested by such serious changes as arrhythmia (ventricular extrasystoles), AV blockade, and even a life-threatening condition - ventricular fibrillation (requires immediate resuscitation measures).

Pathology causes an excessive increase in the load on the right ventricle, and leads to its oxygen starvation and rapidly increasing dystrophic changes. In such situations, the patient is diagnosed with acute cor pulmonale. In the presence of thromboembolism of the pulmonary arteries, blockade of the branches of the bundle of His is not uncommon.

On the ECG, the rise of the RST segment is recorded in parallel in leads III (sometimes in aVF and V1.2). There is an inversion of T in leads III, aVF, V1-V3.

Negative dynamics is growing rapidly (a matter of minutes pass), and progression is noted within 24 hours. With positive dynamics, the characteristic symptoms gradually stop within 1-2 weeks.

Early repolarization of the cardiac ventricles

This deviation is characterized by an upward shift of the RST complex from the so-called. isolines. Another characteristic feature is the presence of a specific transition wave on the R or S waves. These changes on the electrocardiogram are not yet associated with any myocardial pathology, therefore they are considered a physiological norm.

Pericarditis

Acute inflammation of the pericardium is manifested by a significant unidirectional rise of the RST segment in any leads. In some clinical cases, the shift may be discordant.

Myocarditis

Inflammation of the heart muscle is noticeable on the ECG with deviations from the T wave. They can vary from a decrease in voltage to an inversion. If, in parallel, a cardiologist conducts tests with potassium-containing agents or β-blockers, then the T wave remains in a negative position.

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
• condition 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. 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 arrhythmias), 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.

sinus arrhythmia

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 suffering 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.

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. 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 impaired oxygen supply 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, anemia,. 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. They can occur 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 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 most often rare (less than 5 per hour). They are usually functional and do not interfere with the normal blood supply.
• Paired extrasystoles two each accompany a 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 ( 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 ventricular extrasystoles less than 200 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 may be in the form of an attack or permanent form. It manifests itself in the form of flutter or atrial fibrillation.

Atrial fibrillation

Atrial fibrillation

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

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

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

An attack of atrial fibrillation is difficult to miss.

• It usually starts with a strong heartbeat.
• It develops as a series of absolutely non-rhythmic heartbeats with a high or normal frequency.
• The condition is accompanied by weakness, sweating, dizziness.
• The fear of death is very pronounced.
• There may be shortness of breath, general arousal.
• Sometimes observed.
• The attack ends with the normalization of the rhythm and the urge to urinate, in 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 (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 (thromboembolism) increase pulmonary artery, stroke).

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 in detecting ECG signs tachysystole of a permanent form of atrial fibrillation is a decrease in 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, syndrome of weakness of the sinus node, 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 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 may appear as functional disorders, but more often are the results 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, manifestations are added brain symptoms(dizziness, flies in the eyes). 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 blockade are similar to other conduction disorders (CHD, myo- and endocarditis, cardiomyopathies, heart defects, arterial hypertension, fibrosis, heart tumors). Also, the intake of antiarthmic drugs, an increase in potassium in the blood plasma, acidosis, and oxygen starvation also affect.

• The most common is the blockade of the anteroposterior branch of the left leg of the bundle of His (BPVLNPG).
• In second place is the blockade of the right leg (RBNB). This blockade is usually not accompanied by heart disease.
• Blockade of the left leg of the bundle of His more characteristic of myocardial damage. At the same time, complete blockade (PBBBB) is worse than incomplete blockade (NBLBBB). It sometimes has to be distinguished from the WPW syndrome.
• Blockade of the posterior inferior branch of the left leg of the bundle of His may 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.

• (LVH) - typical for arterial hypertension, cardiomyopathy, 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- 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.
• Right atrial hypertrophy (RAH)- with cor pulmonale, tricuspid valve defects, chest deformities, pulmonary pathologies and pulmonary embolism.
• Indirect signs of ventricular hypertrophy is 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- 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

Syndrome of early repolarization of the ventricles

More often all-option norms, especially for athletes and persons 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 () or. Also, reversible diffuse changes accompany disturbances in the water and electrolyte balance (with vomiting or diarrhea), taking drugs (diuretics), severe physical exercise.

Nonspecific ST changes

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). Distinctive feature such changes are reversible. 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 infarct: there are anterior and anterior-septal, basal, lateral, lower (posterior diaphragmatic), circular apical, posterior basal and right ventricular.

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

All the variety of syndromes and specific ECG changes, the difference in indicators for adults and children, the abundance of causes leading to the same type ECG changes, do not allow a non-specialist to interpret even the 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.

Questions that arise during the reading of the article can be asked to specialists using the online form.

Free consultations are available around the clock.

What is an EKG?

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:

Many of our readers actively use the well-known method based on natural ingredients, discovered by Elena Malysheva, for the treatment of HEART DISEASES. We definitely recommend checking it out.

• 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:

1. 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.
2. 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.
3. 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.
4. 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:

1. 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.
2. 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.
3. 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:

1. Measurements of P-wave length, PQ interval length, and QRS complex are evaluated. Excess normal duration interval PQ indicates too low conduction velocity in the corresponding cardiac conduction department.
2. 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 assessed, after which the presence of turns of the heart along one axis or another is established.
3. 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.
4. 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 the same lead and the amplitude values ​​of the R/R waves in different leads.

Having carefully studied the methods of Elena Malysheva in the treatment of tachycardia, arrhythmia, heart failure, stena cordia and general healing of the body, we decided to bring it to your attention.

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 rows list: heart rate, beat rate examples, QT intervals, axis displacement characteristics examples, 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 for all healthy women during pregnancy: 0.1 or less;
• the frequency of contractions of the heart muscle in all healthy women during pregnancy: 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 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 should be noted that during 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.

• Do you often experience discomfort in the area of ​​the heart (stabbing or squeezing pain, burning sensation)?
• You may suddenly feel weak and tired.
• The pressure keeps dropping.
• There is nothing to say about shortness of breath after the slightest physical exertion ...
• And you have been taking a bunch of medications for a long time, dieting and watching your weight.

Deciphering the ECG in adults and children, the norms in the tables and other useful information

Pathology of the cardiovascular system is one of the most common problems affecting people of all ages. Timely treatment and diagnosis of the circulatory system can significantly reduce the risk of developing dangerous diseases.

To date, the most effective and easily accessible method of studying the work of the heart is an electrocardiogram.

Basic Rules

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

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

ECG analysis

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

To date, all these indicators are investigated by high-precision electrocardiographs.

Sinus rhythm of the heart

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

The rhythm is very easy to determine by the highest 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.

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

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

Source of excitation

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

In some cases, other nodes (atrial, ventricular, atrioventricular) can take on the role of the pacemaker. You can determine this by examining the P wave - inconspicuous, located just above the isoline.

What is postmyocardial cardiosclerosis and why is it dangerous? Is it possible to cure it quickly and effectively? Are you at risk? Find out everything!

The reasons for the development of cardiosclerosis of the heart and the main risk factors are discussed in detail in our next article.

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

Conductivity

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

Electric axis

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

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

Teeth, segments and intervals

Teeth - ECG sections lying above the isoline, their meaning is as follows:

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

Intervals are sections of the ECG lying on the isoline.

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

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

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

Norm in men and women

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

Healthy Childhood Outcomes

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

Dangerous diagnoses

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

Extrasystole

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

Arrhythmia

It is characterized by a change in the periodicity of the sinus rhythm, when the impulses arrive at different frequencies. Only 30% of these arrhythmias require treatment, because can lead to more serious illnesses.

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

Bradycardia

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

Tachycardia

The opposite phenomenon, characterized by an increase in heart rate of 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 fever.

Conduction disorder

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

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

Why there might be differences in performance

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

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

Learn all about recovery after a heart attack - how to live, what to eat and how to be treated to support your heart?

Is a disability group allowed after a heart attack and what to expect in terms of work? We will tell in our review.

A rare but accurate myocardial infarction of the posterior wall of the left ventricle - what is it and why is it dangerous?

Additional examination methods

Halter

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

Treadmill

Unlike a normal resting ECG, this method based on the analysis of the results after exercise. Most often, this is used to assess the risk of possible pathologies not detected on a standard ECG, as well as when prescribing a course of rehabilitation for patients who have had a heart attack.

Phonocardiography

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

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

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

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

Deciphering a cardiogram in children and adults: general principles, reading the results, an example of decoding

Definition and essence of the method

How to make an electrocardiogram with the subsequent

The principle of decoding the ECG

ECG interpretation plan - a general scheme for reading the results

• the position of the electrical axis of the heart;
• determination of the correctness of the heart rhythm and the conductivity of the electrical impulse (blockades, arrhythmias are detected);
• determination of the regularity of contractions of the heart muscle;
• determination of heart rate;
• identification of the source of the electrical impulse (determine whether the rhythm is sinus or not);
• analysis of the duration, depth and width of the atrial P wave and the P-Q interval;
• analysis of the duration, depth, width of the complex of teeth of the ventricles of the heart QRST;
• analysis of the parameters of the RS-T segment and the T wave;
• analysis of the parameters of the interval Q - T.

Based on all the studied parameters, the doctor writes a final conclusion on the electrocardiogram. The conclusion may look something like this: “Sinus rhythm with a heart rate of 65. Normal position of the electrical axis of the heart. No pathology has been identified. Or like this: “Sinus tachycardia with a heart rate of 100. A single supraventricular extrasystole. Incomplete blockade of the right leg of the bundle of His. Moderate metabolic changes in the myocardium.

• sinus rhythm or not;
• rhythm regularity;
• heart rate (HR);
• position of the electrical axis of the heart.

If any of the 4 pathological syndromes are identified, then indicate which ones - rhythm disturbance, conduction, overload of the ventricles or atria, and damage to the structure of the heart muscle (infarction, scar, dystrophy).

An example of decoding an electrocardiogram

Checking the regularity of heart beats

Calculation of heart rate (HR)

1. Belt speed is 50 mm/s - then HR is 600 divided by the number of squares.

2. The belt speed is 25 mm/s - then the heart rate is 300 divided by the number of squares.

Finding the Source of the Rhythm

ECG interpretation - rhythms

Identification of the pathology of the conduction of an electrical impulse in the structures of the heart

Electrical axis of the heart

Atrial P wave

• positive in I, II, aVF and chest leads (2, 3, 4, 5, 6);
• negative in aVR;
• biphasic (part of the tooth lies in the positive region, and part - in the negative) in III, aVL, V1.

The normal duration of P is no more than 0.1 seconds, and the amplitude is 1.5 - 2.5 mm.

1. High and sharp teeth in II, III, aVF leads appear with hypertrophy of the right atrium ("cor pulmonale");

2. The P wave with two peaks with a large width in I, aVL, V5 and V6 leads indicates left atrial hypertrophy (for example, mitral valve disease).

P–Q interval

• I degree: simple prolongation of the P-Q interval with the preservation of all other complexes and teeth.
• II degree: prolongation of the P-Q interval with partial loss of some QRS complexes.
• III degree: lack of communication between the P wave and QRS complexes. In this case, the atria work in their own rhythm, and the ventricles in their own.

Ventricular QRST complex

T wave

Q-T interval

ECG interpretation - norm indicators

5. Heart rate is 70 - 75 beats per minute.

6. sinus rhythm.

7. The electrical axis of the heart is located normally.

Deciphering the ECG in children and pregnant women

Deciphering an electrocardiogram in a heart attack

The most acute stage of myocardial infarction can last for 3 hours - 3 days from the moment of circulatory disorders. At this stage, the Q wave may be absent on the electrocardiogram. If it is present, then the R wave has a low amplitude, or is completely absent. In this case, there is a characteristic QS wave reflecting a transmural infarction. The second sign of an acute infarction is an increase in the S-T segment by at least 4 mm above the isoline, with the formation of one large T wave.

Deciphering the most common ECGs

Also, myocardial hypertrophy can be a consequence of myocardial infarction.

What is an ECG, how to decipher it yourself

From this article you will learn about such a diagnostic method as an ECG of the heart - what it is and what it shows. How is the registration of the electrocardiogram, and who can most accurately decipher it. And also you will learn to independently determine the signs of a normal ECG and the main heart diseases that can be diagnosed by this method.

What is an ECG (electrocardiogram)? This is one of the simplest, most accessible and informative methods for diagnosing heart diseases. It is based on the registration of electrical impulses that occur in the heart, and their graphic recording in the form of teeth on a special paper film.

Based on these data, one can judge not only the electrical activity of the heart, but also the structure of the myocardium. This means that with the help of an ECG, many different heart diseases can be diagnosed. Therefore, an independent interpretation of the ECG by a person who does not have special medical knowledge is impossible.

All that a simple person can do is only tentatively assess the individual parameters of the electrocardiogram, whether they correspond to the norm and what kind of pathology they can talk about. But the final conclusions on the conclusion of the ECG can only be made by a qualified specialist - a cardiologist, as well as a general practitioner or family doctor.

Method principle

The contractile activity and functioning of the heart is possible due to the fact that spontaneous electrical impulses (discharges) regularly occur in it. Normally, their source is located in the uppermost part of the organ (in the sinus node, located near the right atrium). The purpose of each impulse is to pass along the conductive nerve pathways through all departments of the myocardium, inducing their contraction. When an impulse arises and passes through the myocardium of the atria, and then the ventricles, their alternate contraction occurs - systole. During the period when there are no impulses, the heart relaxes - diastole.

ECG diagnostics (electrocardiography) is based on the registration of electrical impulses that occur in the heart. For this, a special device is used - an electrocardiograph. The principle of its work is to capture on the surface of the body the difference in bioelectric potentials (discharges) that occur in different parts of the heart at the time of contraction (in systole) and relaxation (in diastole). All these processes are recorded on a special heat-sensitive paper in the form of a graph consisting of pointed or hemispherical teeth and horizontal lines in the form of gaps between them.

What else is important to know about electrocardiography

Electrical discharges of the heart pass not only through this organ. Since the body has good electrical conductivity, the strength of the excitatory heart impulses is sufficient to pass through all the tissues of the body. Best of all, they spread to the chest in the region of the heart, as well as to the upper and lower limbs. This feature lies in ECG basis and explains what it is.

In order to register the electrical activity of the heart, it is necessary to fix one electrode of the electrocardiograph on the arms and legs, as well as on the anterolateral surface of the left half of the chest. This allows you to catch all directions of propagation of electrical impulses through the body. The paths of the discharges between the areas of contraction and relaxation of the myocardium are called cardiac leads and are indicated on the cardiogram as follows:

1. Standard Leads:
   • I - the first;
   • II - second;
   • Ш - the third;
   • AVL (similar to the first);
   • AVF (analogue of the third);
   • AVR (mirror image of all leads).
2. Chest leads (different points on the left half of the chest, located in the region of the heart):

The significance of the leads is that each of them registers the passage of an electrical impulse through a certain part of the heart. Thanks to this, you can get information about:

• How the heart is located in the chest (the electrical axis of the heart, which coincides with the anatomical axis).
• What is the structure, thickness and nature of the blood circulation of the myocardium of the atria and ventricles.
• How regularly impulses occur in the sinus node and whether there are any interruptions.
• Are all impulses conducted along the paths of the conducting system, and are there any obstacles in their path.

What is an electrocardiogram

If the heart had the same structure of all its departments, nerve impulses would pass through them at the same time. As a result, on the ECG, each electrical discharge would correspond to only one tooth, which reflects the contraction. The period between contractions (pulses) on the EGC has the form of a flat horizontal line, which is called an isoline.

The human heart consists of the right and left halves, in which the upper section is distinguished - the atria, and the lower - the ventricles. Since they have different sizes, thicknesses and are separated by partitions, the excitatory impulse passes through them at different speeds. Therefore, different teeth are recorded on the ECG, corresponding to a specific section of the heart.

What do the teeth mean

The sequence of propagation of systolic excitation of the heart is as follows:

1. The origin of electropulse discharges occurs in the sinus node. Since it is located close to the right atrium, it is this section that contracts first. With a slight delay, almost simultaneously, the left atrium contracts. On the ECG, such a moment is reflected by the P wave, which is why it is called atrial. It is facing up.
2. From the atria, the discharge passes to the ventricles through the atrioventricular (atrioventricular) node (accumulation of modified myocardial nerve cells). They have good electrical conductivity, so there is normally no delay in the node. This is displayed on the ECG as a P-Q interval - a horizontal line between the corresponding teeth.
3. Excitation of the ventricles. This part of the heart has the thickest myocardium, so the electrical wave passes through them longer than through the atria. As a result, the highest tooth appears on the ECG - R (ventricular), facing up. It may be preceded by a small Q wave that points in the opposite direction.
4. After the completion of the ventricular systole, the myocardium begins to relax and restore energy potentials. On the ECG, it looks like an S wave (facing down) - complete absence excitability. After it comes a small T wave, facing up, preceded by a short horizontal line - the S-T segment. They say that the myocardium has fully recovered and is ready to make another contraction.

Since each electrode attached to the limbs and chest (lead) corresponds to a specific part of the heart, the same teeth look different in different leads - in some they are more pronounced, and in others they are less.

How to decipher a cardiogram

Sequential ECG decoding in both adults and children involves measuring the size, length of the teeth and intervals, assessing their shape and direction. Your actions with decryption should be as follows:

• Unfold the paper with the recorded ECG. It can be either narrow (about 10 cm) or wide (about 20 cm). You will see several jagged lines running horizontally, parallel to each other. After a short gap, in which there are no teeth, after the recording is interrupted (1–2 cm), a line with several complexes of teeth begins again. Each such graph displays a lead, so it is preceded by a designation of which lead it is (for example, I, II, III, AVL, V1, etc.).
• In one of the standard leads (I, II, or III) that has the highest R wave (usually the second), measure the distance between three consecutive R waves (R-R-R interval) and determine the average value of the indicator (divide number of millimeters by 2). This is necessary to calculate the heart rate in one minute. Remember that such and other measurements can be made with a ruler with a millimeter scale or counting the distance on the ECG tape. Each large cell on paper corresponds to 5 mm, and each dot or small cell inside it corresponds to 1 mm.
• Evaluate the gaps between the R waves: they are the same or different. This is necessary in order to determine the regularity of the heart rate.
• Sequentially evaluate and measure each wave and interval on the ECG. Determine their correspondence normal indicators(table below).

Important to remember! Always pay attention to the speed of the tape - 25 or 50 mm per second. This is fundamentally important for calculating the heart rate (HR). Modern devices indicate the heart rate on the tape, and the calculation does not need to be carried out.

How to calculate the heart rate

There are several ways to count the number of heartbeats per minute:

1. Typically, an ECG is recorded at a speed of 50 mm/sec. In this case, you can calculate the heart rate (heart rate) using the following formulas:

What does an ECG look like in normal and pathological conditions?

What a normal ECG and wave complexes should look like, what deviations are most common and what they indicate, is described in the table.

Probably every adult at least once in his life has come across such a method of examination as an ECG. Many people know that this abbreviation stands for “electrocardiogram” and with its help the heart rhythm is recorded. On this, perhaps, for most patients, all knowledge ends and on the resulting tape they see nothing but a broken line.

For especially curious people who want to find out about their state of health even before visiting a specialist, let's try to figure out how the ECG is decoded and what can be learned from it.

Moreover, on our website you can always get advice from a qualified cardiologist who can interpret the data on the cardiogram tape in detail and accurately.

ECG is not only a modern, but also the most accessible method for determining the characteristics of heart activity. Thanks to portable devices, the procedure can be carried out and read in almost extreme conditions: on the street, at home, in an ambulance or in other transport, and it takes only 5-7 minutes.

Indications for this procedure can be any discomfort that appears in the chest, with "echoes" of pain in the back, left arm, abdominal cavity. In addition, a doctor of any specialization can refer a patient to an ECG as part of a routine examination or if he has:

• severe shortness of breath;
• hypertension;
• interruptions in the rhythm of the heart or noise in it;
• frequent fainting (or after a single case);
• causeless weakness;
• swelling of the extremities, etc.

Patients who have had a heart attack or stroke should be examined according to the prescription of the attending physician. In some cases, it is necessary to record the indicators of the daily work of the heart or with loads. And in order to prevent malfunctions in the work of the organ, even a healthy person should undergo an electrocardiography procedure at least 1 time in 1-2 years.

Can the heart be recorded?

To understand how to decipher a cardiogram, you should learn a little about the principle of the human heart and the method of taking an ECG.

On the wall of the right atrium there is a sinus node, from which the propagation of impulses normally begins. Passing through the muscles of the atrium, the excitation reaches the antroventricular node, then into the bundle of His and along its legs, the impulse propagates through the tissues of the ventricles. All this causes 4 sections of the heart to contract. It is this pattern of excitations that is normal and gives rise to sinus rhythm.

As is known, human body It has electrical conductivity, so the biocurrents of the heart can be projected onto its surface and recorded using ECG devices.

From the point of view of physics, an electrocardiogram is nothing more than a registration of electrical signals, which is carried out from several sections of the heart muscle. To do this, plates are attached to certain points of the body that transmit signals to the ECG apparatus.

In practice, 3 standard bipolar leads (I, II, III), 3 reinforced unipolar leads (aVR, aVL, aVF), which are attached to the limbs, and 6 reinforced unipolar chest leads (V 1 -V 6) are used. But, despite the simplicity of their layout, only a trained physician can correctly fix the electrodes, otherwise the ECG results will be incorrect. Three more leads (V 7 -V 9) are less commonly used, which provide more accurate information about abnormalities in the myocardium of the posterior wall of the left ventricle.

From the video below, you can learn more about the propagation of impulses in the heart and the correct application of electrodes during an ECG.

Prongs and intervals

All received electrical signals are converted into graphic information and applied to a special tape, which is divided into squares of 1 mm 2 . Thus, we see the whole process of the work of our heart as a curve with pronounced teeth, for convenience they have their own “names”: P, Q, R, S, T.

Each tooth reflects certain actions of the heart muscle and their duration:

• P - excitation of the right and then the left atrium, united by one tooth (at least 0.12 s.);
• Q - excitation of the interventricular septum (0.03 s);
• R - excitation of the apex of the heart with the adjacent area (0.05 s.);
• S - excitation of the base of the organ (0.02 s.);

The Q, R, S waves are considered as a single ventricular complex (0.10 s).

• T - this wave displays repolarization, that is, the restoration of the initial state of all parts of the heart.

The teeth form corresponding segments and intervals between themselves.

When deciphering a cardiogram, specialists usually adhere to a certain sequence.

Heart rate and frequency

Normally, the rhythm should be sinus, that is, the impulse "originates" in the sinus node. This will be indicated by the P wave, which should precede the QRS complex and be positive in all leads except aVR. If this is not the case, then we can talk about the pathology of the heart. In case of weakness of the sinus node, the atrioventricular node, bundles of His, or Purkinje fibers can become the pacemaker. This information can be indicated by the functional diagnostician on the ECG tape. In addition, it indicates the heart rate (HR), which, however, can be calculated independently. To do this, it is enough to find out at what speed the ECG was recorded and find out R-R distance(count the number of small squares between them).

If the writing speed is 25 mm / s, then it should be calculated according to the following formula:

HR= 60/R-R*0.04;

If - 50 mm / s, then heart rate \u003d 60 / R-R * 0.02;

For an adult, the normal heart rate is 60-90 beats per minute. For children, all indicators of the cardiogram change and "grow" with them. For example, the frequency varies from 110 in the first months of life to 90 strokes in adolescence.

If the rhythm is accelerated, then this indicates tachycardia, if slowed down, then bradycardia, and if the R-R distance is not the same, then this condition is called arrhythmia.

The figure shows examples of normal heart rhythm (a), tachycardia (b), bradycardia (c) and irregular rhythm (arrhythmia) of an adult (d).

Electrical axis of the heart

Next, the specialist draws attention to the location of the EOS. It can be not only normal, but also have a vertical, horizontal orientation, or be deviated to one of the sides. This indicator may depend on several factors at once - high growth, overweight, age, pregnancy, etc., therefore, it is not worth immediately and unequivocally making conclusions about deviations in the work of an adult organ. However, as well as ignore the changes, especially if the axis shift happened quite abruptly. This may indicate problems with the respiratory system, the development of heart disease, changes in the myocardium, atherosclerosis, etc. In this case, an additional examination of the patient will be scheduled.

When reading an ECG to determine the EOS, the following algorithm is used.

Wave and spacing analysis

ECG analysis is not complete without monitoring the waves and intervals. It all starts with the P wave, which, as mentioned above, should be sinus. If it in the second lead has an increased amplitude or duration, then this may indicate hypertrophy of the right or left atrium, respectively. Further, evaluating the PQ interval, it is possible to identify the blockade of the antroventricular node, which is characterized by an increased duration of the PQ interval or its complete absence.

A separate point in the analysis of the ECG is the reading of the QRS complex. Normally, its duration is 60-100 ms. Its elongation is evidence of a conduction disturbance in the legs of the His bundle. Below are examples of areas of the ECG, where the blockade of the right and left legs is clearly visible.

Moreover, a Q wave deeper than 1/3 of the R wave may indicate myocardial infarction.

The QT interval displays the duration of ventricular contraction and is 390-450 ms. Its lengthening indicates the development of coronary heart disease, and its shortening indicates hypercalcemia. The ST segment normally should not rise above the isoline by more than 1 mm and decrease by more than 0.5 mm. Violation of the first condition indicates an acute infarction or pericarditis, and the second - about ischemia.

The video shows the sequence and more detailed decoding of all the teeth of the ECG intervals:

But no matter how detailed such information is presented, it should be understood that only a specialist can correctly interpret the cardiogram.

The ruler is an indispensable assistant

Sometimes it happens that a person's life depends on precious minutes, during which the doctor must understand what is the reason for the deterioration of the patient's condition and take appropriate measures. Ambulance paramedics sometimes have to make a diagnosis right at the patient's home, relying only on electrocardiography indicators. It goes without saying that the analysis in such a situation must be carried out extremely quickly and at the same time correctly. For such emergencies and to help medical students, a ruler was developed for interpreting the obtained ECG.

With its help, you can quickly read the ECG: determine the heart rate, measure and compare intervals with the norm, their duration, and also determine the EOS. Such an invention as a ruler can also become useful when trying to decipher the ECG on your own.

Other ways to look into the "motor" of the human body

In addition to the electrocardiogram, modern medicine has such methods of examination of the heart as echocardiography and the method of daily monitoring of heart rate.

Holter method

This method allows you to obtain continuous data on the work of the heart for 24 hours (and sometimes even up to 7 days). Daily monitoring allows you to identify pathologies that are determined in special conditions. To do this, 2 or 3 electrodes (rarely more) are attached to the patient's body, a registrar is worn on the belt or over the shoulder on the belt, which keeps a continuous record. At the same time, the subject leads a normal life, with the usual physical activity, recording the time and circumstances in which unpleasant sensations appeared.

Recorders are divided into those that record on magnetic media and those that have digital memory. The analysis of the accumulated information is carried out on a computer with the software installed for this, but it is not complete without adjusting the results by a specialist. The conclusion on daily monitoring of the work of the heart contains the same mandatory items as in a conventional ECG. Only information about well-being is added, according to the diary, prescribed loads and related changes.

Echocardiogram

Like any organ, the heart is subject to ultrasound. The doctor performing the procedure sees a real-time video of the beating heart on the screen. Like conventional ultrasound, echocardiography is absolutely painless and has no contraindications. EchoCG may be prescribed if the patient:

• Murmurs in the heart;
• Signs of ventricular failure;
• IHD in chronic or acute form;
• chest trauma;
• Suspicion of aortic aneurysm or other vascular abnormalities, etc.

During echocardiography, a functional diagnostician can establish:

• Condition of all heart valves;
• The dimensions of all chambers of the heart and the thickness of their walls;
• Direction of blood flows and their speed;
• Pressure in the pulmonary artery.

To identify hidden pathologies or abnormalities that are not diagnosed at rest, certain loads can be assigned to the patient during echocardiography. This is called stress echo.

As practice shows, three factors can affect the results of echocardiography:

• Features of the patient, for example, obesity, specific location of the heart, chest deformity, emphysema.
• Experience and qualifications of a functional diagnostician.
• Ultrasound class.

Therefore, only one result of echocardiography does not make final conclusions about the health of the heart and does not make diagnoses. This procedure is usually prescribed in combination with electrocardiography.

conclusions

This article is more of a fact-finding character, because only a cardiologist who has been studying the heart for many years can read an electrocardiogram correctly. Thus, each person will be able to determine whether he has a sinus rhythm, heart rate, compare the duration of the intervals with the norm, and, guided by the proposed algorithm, set the EOS.

But it is worth reminding once again, if you find any abnormalities on your ECG, do not rush to diagnose yourself and take medication - wait for the doctors' opinion.

Cardiogram of the heart decoding is a special section of cardiology. Among the huge variety of instrumental research methods, of course, the leading place belongs to electrocardiography. Cardiogram of the heart decoding is a method for assessing the bioelectrical activity of the heart muscle. It allows diagnosing rhythm and conduction disorders, ventricular and atrial hypertrophy, ischemic disease and many other diseases. Cardiogram of the heart decoding includes measuring the length, amplitude of the teeth, the size of the segments, the presence of pathological changes in the normal cardiographic pattern.

The cardiogram of the heart decoding begins with the study of a normal ECG. When you know what the norm looks like, it is not difficult to guess in which particular section of the heart muscle pathological changes occurred. Any cardiogram consists of segments, intervals and teeth. All this reflects the complex process of transmission of a wave of excitation through the heart.

The main components of the ECG:

1. 
   teeth: P, Q, R, S, T;
2. 
   six main leads: I, II, III, AVL, AVR and AVF;
3. 
   six chest: V1, V2, V3, V4, V5, V6.

Prong P

PQ interval

Q wave

R wave

S wave

ST segment

T wave

Deciphering the cardiogram of the heart is not an easy and time-consuming task, it is important to remember many nuances and take them into account when describing. That is why this science was transferred into the hands of electrocardiologists.

Heart arrhythmias- these are disorders in which the functions of the heart change, providing a rhythmic and consistent contraction of its departments. Sinus rhythm- this is a normal heart rate, it is equal to 60 to 90 beats per minute at rest. The number of heartbeats in a person depends on various reasons. With physical exertion, an increase in body temperature, strong emotions, the frequency of the rhythm increases. To pathological changes heart rate include: sinus tachycardia, sinus bradycardia, atrial fibrillation, sinus arrhythmia, extrasystole, paroxysmal tachycardia.

Sinus tachycardia

Treatment of sinus tachycardia depends on the underlying disease. With neuroses, sedatives are prescribed (valerian tincture, Corvalol, etc.). If tachycardia is caused by a heart disease, cardiac glycosides and other drugs are prescribed.

Electrocardiogram for tachycardia

Sinus bradycardia

Sinus bradycardia does not disturb hemodynamics and does not require special treatment. If the bradycardia is very pronounced, drugs that stimulate the heart, such as aminophylline, caffeine, etc., can be prescribed. The prognosis of sinus bradycardia depends on the underlying disease.

Electrocardiogram for bradycardia

Atrial fibrillation

Sinus arrhythmia can develop with various heart diseases (rheumatism, cardiosclerosis, myocardial infarction, etc.), with intoxication with various substances (digitis, morphine, etc.).

If sinus arrhythmia is not associated with breathing, then it manifests itself in two forms: a periodic variant (gradual acceleration and deceleration of the rhythm), and a non-periodic variant (lack of correctness in changing the rhythm). These arrhythmias are usually seen with serious illnesses heart and, in very rare cases, with autonomic dystonia or an unstable nervous system.

Respiratory arrhythmia does not require treatment. In some cases, valerian, bromides, belladonna may be prescribed. If sinus arrhythmia is not associated with breathing, the underlying disease is treated.

Clinical manifestations depend on those diseases that are accompanied by extrasystole. Patients sometimes may not feel the extrasystole at all. For some people, an extrasystole is perceived as a beat in the chest, and a compensatory pause is felt as a feeling of cardiac arrest. The most serious extrasystole is with myocardial infarction.

Treatment for extrasystole is aimed at the underlying disease. If necessary, sedatives are prescribed and sleeping pills. The optimal mode of work and rest is assigned.

Electrocardiogram with extrasystole

Paroxysmal tachycardia

With paroxysmal tachycardia, patients complain of a sudden strong heartbeat, the onset of an attack is felt like a push in the chest. The attack stops suddenly with a feeling of short-term cardiac arrest and a subsequent strong blow. The attack may be accompanied by weakness, fear, dizziness, in some cases, fainting may occur.

Paroxysmal tachycardia requires mandatory treatment. Calming and hypnotic drugs are prescribed, as well as other drugs that relieve and prevent an attack. In some cases, with the ineffectiveness of drug treatment and with a severe course of the disease, surgical treatment is used.

Deciphering the ECG of the heart

• 
  the nature of the heart rate and the determination of the exact value of contractions in the time interval
• 
  cycle of cardiac biopotentials
• 
  excitation source recognition
• 
  conductivity assessment
• 
  study of the P wave and ventricular QRST interval
• 
  designation of the axis of signal propagation and the position of the heart relative to it

ECG decoding is a graphical display of the intensity of a given discharge, which helps to determine malfunctions in the work of the cardiac departments.

The rhythm of contractions of the heart muscle is determined by the duration of the measurement of R-R intervals. If their duration is the same or marked fluctuations of 10%- this is considered the norm, in other cases we can talk about a violation of the rhythm.

ECG indicators and their interpretation

Heart rate (HR)

We list the main ECG indicators that interest us on the cardiogram:

• 
  Teeth - characterize the stages of the cardiac cycle
• 
  6 leads - parts of the heart, displayed in numbers and letters
• 
  6 chest - fix changes in cardiac potentials in the horizontal plane

We begin to measure the height of the teeth from isolines- a horizontal straight line using a ruler, taking into account the location of the positive teeth above the straight line and the negative ones - below the axis.

Their shape and size depend on the passage of an electric wave and differ in all leads. Using the automatically specified formula, we calculate the duration intervals and segments- divide the distance between the segments by the speed of the tape.

PQ QRS QT interval displays impulse conduction

The values ​​​​of the teeth on the cardiogram

Deciphering the ECG in children

The norm is:

• 
  deep Q wave position
• 
  sinus arrhythmia
• 
  the ventricular QRST interval is subject to alternation (change in the polarity of the T waves)
• 
  movement of the source of rhythm is noted in the atria
• 
  as the child grows older, the number of chest leads with a negative T wave decreases
• 
  the large size of the atria determines the height of the P wave
• 
  The age of the child affects the ECG intervals - they become longer. In young children, the right ventricle predominates

What does sinus rhythm mean on a cardiogram

The rhythm indicated by 110 beats indicates the presence of sinus tachycardia. The cause of its occurrence may be physical activity or nervous excitability. This condition may be temporary and does not require long-term treatment.

With anemia, myocardium or fever, a persistent manifestation of tachycardia with palpitations was noted. The interpretation of the ECG in this case determines an unstable sinus rhythm, and indicates an arrhythmia - an increased frequency of contractions of the heart departments.

Children also have a similar symptom, but the sources of origin are different. These are cardiomyopathy, endocartitis and psychophysical overload.

The rhythm may be disturbed from birth, have no symptoms, and be detected during electrocardiography.

Deciphering the cardiogram. The work of the heart.

Heart it seems to work simply - contracting and reducing the volume of the chambers (systole), pushes oxygen-rich blood into the body, and relaxing (diastole) - receives blood back. Four chambers contract - 2 ventricles and 2 atria. In the presence of atrial fibrillation, the atria contract irregularly and do not drive blood, but you can live with this, but you cannot live without the normal functioning of the ventricles.

The work of the heart It is provided by electrical impulses (produced in the heart itself), nutrients, oxygen and the correct ionic balance of Ca, K, Na ions both inside and outside the cell.
Calcium provides contraction - the more it is, the stronger the contraction. If it is excessive, then the heart may contract and not relax. Calcium channel blockers (such as verapamil) reduce the force of contractions, and this is useful for angina pectoris. When potassium levels are high, the heart may stop when it relaxes.

With a heart mass of about half a percent of body weight, it consumes up to 10% of oxygen.

Getting energy from the heart. Unlike the brain, which needs only glucose, the heart at rest consumes fatty acids, lactic acid. And with an increase in the load, the heart switches to the consumption of glucose, which is more beneficial. To reduce the heart's need for oxygen, the energy metabolism is shifted towards glucose (trimetazidine), which is important for patients with angina pectoris and myocardial infarction.

When the heart begins to fail its pumping function, heart failure(acute or chronic. It may be the result of poor left ventricular function, then there is insufficient blood flow in the pulmonary circulation, shortness of breath occurs, a person in a supine position does not have enough air and it is easier for him to sit. With poor work of the right ventricle, edema occurs in the legs. See. angina pectoris).

To understand the nature of the electrical impulses of the heart, let's get acquainted with its conducting system. If you cut all the nerves leading to the heart, it will continue to beat - impulses are generated by the heart itself at certain nodes and spread through the heart.

Composition of the conducting system:

• 
  Sinus - atrial node
• 
  Atrioventricular node
• 
  Bundle of His with left and right legs
• 
  Purkinje fibers

Comparing the electrocardiograms of a healthy (1) and diseased (2) heart, one can see a clear difference between them and judge the nature of the damage to the heart muscle.

The shape and type of teeth, the duration and type of intervals of the cardiogram are directly related to the phases of excitation and relaxation of the heart muscles. The work of the atria is characterized by the P wave (the ascending section is the excitation of the right, the descending section is the excitation of the left atria), and the period of time when both atria are active is called PQ. The Q and R waves show the activity of the lower and upper parts of the heart. In the same period of time, the ventricles (their outer parts) are active. The ST segment is the activity of both ventricles, and the T wave means the transition of the heart muscles to a normal state.