What should be the ecg. Intervals and ecg waves are normal

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 diseases heart (the presence of areas 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 hypertrophy of the left ventricle, the R wave is pronounced in the left chest leads and increased its depth 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 "ventricular preexcitation syndrome" on the ECG, the width of the QRS complex increases and becomes shorter R-R interval. 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 the P-Q interval, and in the most severe cases - total absence connections between QRS and R.

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 heart rhythm disturbances, the 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 angina attack, 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. Registered on the ECG pathological changes only in rare cases are associated with such clinical symptoms as pain in the chest area.

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 the QT interval are determined. “Smoothing” of the RST segment and shortening of T cannot be excluded. Overdose of glycosides is manifested by such serious changes as arrhythmia (ventricular extrasystoles), AV blockade, and even life threatening condition - ventricular fibrillation (requires immediate resuscitation).

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.

ECG interpretation is performed by a qualified specialist. This method functional diagnostic checks:

1. Heart rate: what is the state of the generators of the electrical impulse and the cardiac systems that conduct these impulses.
2. Cardiac muscle: its condition and performance, damage, inflammation and other pathological processes that could affect the condition of the heart.

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Heartbeat

Patients collect the electrocardiogram along with its results. It cannot be decrypted by itself. To read the diagram, you need a special medical education. No need to be nervous before meeting with a functional diagnostician. At the appointment, he will tell you all the risks of the diagnosis, prescribing effective treatment. But if a patient is diagnosed serious illness then you need to consult a cardiologist.

When the decoding of the ECG did not give clear results, the doctor may prescribe additional studies:

• ECG control;
• Holter (monitoring of the work of the heart throughout the day);
• Ultrasound of the heart muscle;
• Treadmill (a test for the performance of the heart during exercise).

The results of measurements using these studies are an accurate indicator of the work of the heart. If there are no failures in the work of the myocardium, the tests will have good results.

On the ECG healthy person there is an inscription "Sinus rhythm". If the frequency of beats per minute up to 90 is added to this inscription, the results are good, the heart works without interruption. Sinus rhythm is a measure of the rhythm of the sinus node, which is the main rhythm producer for regulating and generating electrical impulses with which the heart muscle contracts. The description of the electrocardiogram, which includes sinus rhythm, is the norm, indicating the health of the sinus node and the heart muscle itself.



If the cardiogram of the heart does not have any other notes in its description, it indicates the overall health of the heart. Sinus rhythm can be replaced by atrial, atrioventricular or ventricular. These types of rhythms indicate that contractions are carried out precisely by these parts of the heart, which is considered a pathology.



What is a lipidogram and lipid spectrum of blood - decoding of the analysis

What is sinus arrhythmia?

Sinus arrhythmia is a common diagnosis in childhood and adolescence. It is characterized by different time intervals between sinus contractions of the heart muscle. Experts say that this pathology can be caused by changes at the physiological level. Up to 40% of sinus arrhythmias should be monitored by a cardiologist. Patients should be examined and re-examined every 3-4 months. Such precautions will protect you as much as possible from the development of more serious heart diseases.



Sinus bradycardia is the rhythm of heart contractions up to 50 times per minute. This phenomenon is also possible in healthy people during sleep or in professional athletes. Pathological bradycardia may be a sign of sick sinus syndrome. This case implies a severe bradycardia, reaching up to 35 heartbeats per minute. You can observe such a pathology all the time, and not just at night.

If bradycardia consists of pauses between contractions of up to 3 seconds during the day and up to 5 seconds at night, there may be a violation of the supply of oxygen to the tissues, which usually leads to fainting. Only a pacemaker of electrical origin, which is placed directly on the heart during surgery, will help get rid of this problem. The installation takes place at the site of the sinus node, which further allows the heart to work without failures.

Causes of a poor cardiogram may be related to sinus tachycardia, which is a heart rate contraction of more than 90 times per minute. It is divided into physiological and pathological tachycardia. Healthy people may experience sinus tachycardia during physical and emotional stress, drinking coffee or strong tea, alcohol-containing drinks and energy drinks. Sinus tachycardia after active pastime is a brief manifestation. After the manifestation of an increased number of beats, the rhythm returns to its normal state in a sufficiently long time. a short time after reducing the intensity of physical activity.



With pathological tachycardia, a rapid heartbeat worries the patient all the time. The cause of increased heart rate can be: fever, infection, blood loss, dehydration, anemia, and more. Treat the underlying cause causing tachycardia. Relief of sinus tachycardia occurs only in the case of myocardial infarction or acute coronary syndrome.



How is extrasystole manifested?

The specialist can determine this pathology immediately, since this is a change in rhythm, the nature of which is the foci behind the sinus rhythm. They give extra contractions of the heart muscle. After this process, a pause doubled in time appears, the name of which is compensatory. Patients believe that such a change in the heartbeat occurs on the basis of nervous stress. Rhythm can be both rapid and slow, sometimes chaotic. The patient himself can notice the dips that occur in the rhythm of the heartbeat.

An example of deciphering an ECG with extrasystole is an example with a pathology that is visible even to non-specialists. Some patients complain not only of changes in rhythm, but also of unpleasant and pain in the chest area. They experience jolts, tingling, a constricting feeling of fear rising in the abdomen.



Such manifestations are not always pathological and life-threatening.

Many types of extrasystoles do not depress blood circulation and do not reduce the efficiency of the heart.

Extrasystoles are divided into 2 types:

• functional (manifested against the background of panic and nerves);
• organic (if a person has heart defects, myocarditis and congenital problems with the cardiovascular system).

In 20% of cases, the cause of the disease is intoxication or surgery in the heart area. A single manifestation of extrasystole occurs rarely (up to 5 times in 1 hour). Such dips are functional in nature, they are not an obstacle to normal blood supply. There are times when paired extrasystoles occur. They appear after a series of normal contractions. It is this rhythm that is an obstacle to the normal functioning of the heart muscle. For an accurate diagnosis of this manifestation, an additional ECG analysis and Holter are prescribed with a setting for a day.



The main classes of pathology

Extrasystoles also have the appearance of allorhythmia. When an extrasystole appears on every second contraction, specialists diagnose bigeminia, on every third - trigeminia, on every fourth - quadrigeminia. According to Laum's classification, ventricular extrasystoles are divided into 5 classes depending on the daily examination indicators:

1. 1. Isolated cases of manifestation of the disease up to 60 times every hour, united by one focus (monotopic).
2. 2. Constant monotopic changes, manifested in an amount of more than 5-6 times every minute.
3. 3. Permanent polymorphic (have different shape) and polytopic (have a different focus of occurrence) changes.
4. 4. Paired or group, accompanied by episodic attacks of paroxysmal tachycardia.
5. 5. Early manifestation of extrasystoles.

For treatment, medications are not prescribed. With the manifestation of the disease less than 200 times a day (Holter monitoring will help to establish the exact number), extrasystoles are considered safe, so you should not worry about their manifestations. Regular examinations by a cardiologist every 3 months are required.

If the patient's electrocardiogram revealed pathological contractions more than 200 times every day, then additional examinations are prescribed. Specialists prescribe ultrasound of the heart and magnetic resonance imaging (MRI) of the heart muscle. The treatment of the manifestation is specific and requires a special approach, since it is not extrasystoles that are treated, but the root causes of their occurrence.



Paroxysmal tachycardia

Paroxysm is a manifestation of an attack. A similar process of increased heart rate can last for several hours or several days. The electrocardiogram displays the same intervals between muscle contractions. But the rhythm changes and can reach more than 100 beats in 1 minute (the average is 120-250 times).



Doctors isolate the supraventricular and ventricular species tachycardia. The basis of this pathology lies in the abnormal circulation of an electrical impulse in the cardiovascular system. You can get rid of this manifestation at home, but for a while: you need to hold your breath, start coughing angrily or dip your face in cold water. But such methods are ineffective. Therefore, there is a medical method for the treatment of paroxysmal tachycardia.

One of the varieties of supraventricular tachycardia is Wolff-Parkinson-White syndrome. The title includes the names of all the doctors who described it. The reason for this type of tachycardia is the appearance between the atria and ventricles of an extra bundle of nerves that conducts the rhythm faster than the main driver. As a result - the occurrence of one extra time of contraction of the heart. Such a pathology can be cured conservatively or surgically. The operation is prescribed only in case of low efficiency or allergy in the patient to the active components of the treatment, with atrial fibrillation or heart defects of a different nature.

Clerk-Levy-Christesco syndrome is a manifestation similar to the previous pathology, but it is characterized by an earlier than normal stimulation of the ventricles with the help of an additional bundle through which the nerve impulse passes. The syndrome is congenital pathology. If you decipher the cardiogram of the heart, its manifestation can be seen immediately by attacks of rapid heartbeat.



Atrial fibrillation

During fibrillation, irregular contractions of the heart muscle are observed with intervals of varying length between contractions. This is explained by the fact that the rhythm is not set by the sinus node, but by other cells of the atria. The frequency of contractions can even reach 700 beats in 1 minute. A full-fledged atrial contraction is simply absent, it falls on muscle fibers that do not allow the ventricles to be completely filled with blood. The consequence of this process is the deterioration of the ejection of blood by the heart, which leads to oxygen starvation of organs and tissues of all body systems.

Atrial fibrillation has another name: atrial fibrillation. In fact, not all atrial contractions go directly to the ventricles. This leads to a decrease normal pulse(bradysystole, which has a frequency of contraction less than 60 times per minute). But the contraction of the heart can be normal (normosystole, 60-90 times per minute) and increased (tachysystole, more than 90 times per minute).



Determining atrial fibrillation on an electrocardiogram is easy, since attacks are difficult to miss. The beginning of an attack in 90% of cases is a strong push of the heart muscle. Then there is the development of a series of non-rhythmic fluctuations of the heart with an increased or normal frequency. The patient's condition also worsens: he becomes weak, sweaty, dizzy. The patient wakes up with a pronounced fear of death. There may be shortness of breath and an excited state. Sometimes there is a loss of consciousness. It is also easy to read the cardiogram at the final stage of the attack: the rhythm returns to normal. But the patient feels a strong desire to urinate, during which enough a large number of liquids.

The relief of the disease is carried out using reflex methods, drugs in the form of tablets or injections. Less commonly, specialists perform cardioversion - stimulation of the heart muscle using an electric defibrillator. If attacks of ventricular fibrillation are not eliminated within 2 days, complications may occur. Thromboembolism may occur pulmonary artery, stroke.

A constant form of flickering that does not help medical preparations, nor electrical stimulation of the heart, becomes commonplace in the patient's life and is felt only during tachysystole (increased heart rate). If the electrocardiogram revealed tachysystole and atrial fibrillation, then it is necessary to reduce the number of heart contractions to normal without trying to make them rhythmic. Atrial fibrillation can appear against the background of coronary heart disease, thyrotoxicosis, heart defects of various nature, diabetes mellitus, sick sinus syndrome, intoxication after alcohol poisoning.



atrial flutter

Atrial flutter - constant and frequent contractions of the atria (more than 200 times per minute) and ventricles (less than 200 times). flutter in 90% of cases sharp shape, but is much better tolerated and easier than fibrillation, since changes in blood circulation are less pronounced. The development of flutter is possible against the background of heart disease (cardiomyopathy, heart failure), after surgery on the heart muscle. With obstructive pulmonary disease, it practically does not manifest itself. Reading an ECG with this disease is easy, as it is manifested by frequent rhythmic heartbeats, swollen veins in the neck, shortness of breath, increased sweating and weakness.



In the normal state, an electrical excitation is formed in the sinus node, which passes through the conducting system. It experiences a delay of a physiological nature for literally a fraction of a second in the region of the atrioventricular node. The atria and ventricles, whose function is to pump blood, are stimulated by this impulse. If the impulse is delayed in some part of the system, it reaches other areas of the heart later, which leads to disturbances in the normal operation of the pumping system. Changes in conduction are called blockade.

The occurrence of blockades is functional disorder. But the reason for their occurrence in 75% of cases is alcohol or drug intoxication and organic diseases of the heart muscle. There are several types of blockades:

1. 1. Sinoatrial blockade: the passage of the impulse directly from the sinus node is difficult. Then this blockade develops into a syndrome of weakness of the sinus node, leads to a decrease in the number of contractions until a new blockade, disruption of the blood supply to the peripheral section, shortness of breath, weakness, dizziness and loss of consciousness.
2. 2. Blockade of Samoilov-Wenckebach - the second degree of the sinoatrial blockade.
3. 3. Atrioventricular block is delayed excitation of the atrioventricular node for more than 0.09 seconds. There are 3 degrees of blockade of this type. At the highest degree of the disease, the ventricles are more likely to contract. Therefore, in the highest stages, circulatory disturbances become more severe.

Conduction disorders in the ventricles

The electrical signal travels inside the ventricles to special cells made of muscle tissue. The propagation of this signal is carried out through systems such as the bundle of His, its legs and their branches. The cause of a bad cardiogram is the occurrence of disturbances in the conduction of an electrical signal. Specialists easily diagnose this deviation from the norm on the ECG. At the same time, the diagram clearly shows that one of the ventricles is stimulated later than the second, because the signaling is made with a delay, passing along bypass routes due to blockade of the desired area.



The blockade is classified not only by the place of occurrence, but also by type. There are complete and incomplete blockades, permanent and non-permanent. The root causes of blockades inside the ventricles are the same as in other diseases with poor conductivity: ischemic disease, cardiomyopathy, malformations of a different nature, fibrosis, cancers in the heart. May affect the occurrence of the disease consumption of antiarrhythmic drugs, increased levels of potassium in the blood, oxygen starvation and other.

Most often there is a blockage of the upper branch on the left leg of the bundle of His. The second place is taken by the blockade of the entire region right leg. It does not occur on the basis of other heart diseases. The blockade of the left leg occurs with myocardial lesions in a number of diseases. lower branch the left leg suffers from pathological changes in the structure of the human chest. It can also occur when overloading the right ventricle.

Doctors obtain important information about the state of the heart using an ECG (electrocardiography). This simple study allows you to identify dangerous diseases of the cardiovascular system in adults and children and prevent their further development.

Electrocardiography provides detailed information about the condition of the heart

ECG - what is it?

Electrocardiography (cardiogram) is a determination of the electrical activity of the heart.

With the help of the procedure, you can find out:

• heart rate and conduction;
• the presence of blockades;
• the size of the ventricles and atria;
• blood supply to the heart muscle.

The cardiogram is the main study that can identify a number of dangerous diseases- myocardial infarction, heart defects, heart failure, arrhythmia.

Cardiogram helps to identify abnormalities in the work of the heart

Thanks to the ECG, it is possible to detect not only cardiac disorders, but also pathologies in the lungs, endocrine system (diabetes), vessels (high cholesterol, high blood pressure).

No special preparation is required to undergo a heart examination. In public hospitals, an ECG requires a referral from the attending physician, the procedure is free.

Private clinics do not need a referral, but here the study is paid:

• the price of registering a cardiogram without decoding is 520–580 rubles;
• the cost of the decryption itself - from 430 rubles;
• ECG at home - from 1270 to 1900 rubles.

The cost of the procedure depends on the technique and the level of qualification of the hospital.

ECG methods

For complex diagnostics Cardiac activity There are several methods for conducting an electrocardiogram - a classic cardiogram of the heart, an ECG according to Holter and a stress ECG.

Classic cardiogram

The most common and simplest way to study the strength and direction of electrical currents that appear during each push of the heart muscle. The duration of the procedure does not exceed 5 minutes.

During this time, specialists manage to:

• study the electrical conductivity of the heart;
• detect heart attack pericarditis;
• examine the chambers of the heart, identify the thickening of their walls;
• determine the effectiveness of the prescribed therapy (how the heart works after taking certain medications).

The classical cardiogram is a simple and affordable method for examining the heart.

The disadvantage of this method is that it is carried out at rest. Therefore, pathologies that manifest themselves during stress (emotional, physical) or during sleep, this method of diagnosis will not be able to fix. In these cases, the doctor relies on the patient's complaints, the main signs and may prescribe other types of research.

The technique allows you to identify pathologies that do not appear in a calm state. The device records cardiac activity throughout the day and makes it possible to determine the moment of failure in the conditions familiar to the patient (during physical exertion, during stress, in sleep, while walking or running).

Thanks to the Holter study, it is possible to:

• to determine at what moments irregular appears heartbeat and what provokes it;
• identify the source of a feeling of pressure or burning in the chest, fainting or dizziness.

Heart rhythms according to the Holter method are measured for at least a day

Stress ECG is a monitoring of the work of the heart during exercise (exercises on a treadmill, exercises on an exercise bike). It is performed in the case when the patient has periodic disturbances in cardiac activity, which electrocardiography cannot detect at rest.

An exercise ECG allows you to:

• to identify the factors provoking deterioration in the period physical activity;
• find the cause of sudden pressure surges or irregular heartbeats;
• monitor exercise after a heart attack or surgery.

The study allows you to choose the most appropriate therapy, and monitor the effect medicines.

Stress ECG is performed to study the work of the heart under stress

Indications for electrocardiography

Usually, a heart cardiogram is prescribed based on the patient's complaints and the presence of unpleasant symptoms:

• pressure surges, more often upward;
• difficulty breathing, turning into shortness of breath even at rest;
• pain in the region of the heart;
• murmurs in the heart;
• diabetes;
• destruction of joints and muscles with damage to blood vessels and the heart (rheumatism);
• causeless disturbance of the pulse.

A cardiogram is always prescribed after a stroke, frequent fainting, and also before any surgical intervention.

With frequent pain in the heart, it is necessary to make a cardiogram

Study preparation

Electrocardiography does not require special preparation. For more reliable indicators, experts recommend adhering to simple rules on the eve of the study.

1. Relaxation. You need to sleep well, avoid emotional outbursts and stressful situations, do not overstrain the body with physical exertion.
2. Food. Do not overeat before the procedure. Doctors sometimes recommend fasting heart monitoring.
3. Drink. A few hours before the cardiogram, it is recommended to consume less liquid in order to reduce the load on the heart.
4. Meditation. Before the procedure itself, you need to calm down, take a deep breath, then exhale. Normalization of breathing has a positive effect on the functioning of the cardiovascular system.

Get a good night's sleep before an ECG

How is an EKG performed?

Many have come across a cardiogram of the heart and know that the procedure takes 5-7 minutes and consists of several stages.

1. The patient needs to expose the chest, forearms, wrists and shins. Lie down on the couch.
2. The specialist treats the areas where the electrodes will fit with alcohol and a special gel, which contributes to a better fit of the wires.
3. After fixing the cuffs and suction cups, the cardiograph is turned on. The principle of its operation is that it reads the rhythm of heart contractions with the help of electrodes and fixes any disturbances in the functioning of a vital organ in the form of graphic data.

The resulting cardiogram requires decoding, which is carried out by a cardiologist.

Special suction cups are placed in the region of the heart to measure heart rate

Contraindications for electrocardiography

A regular ECG does not harm the body. The equipment reads only cardiac currents and does not affect other organs. Therefore, it can be done during pregnancy, children and adults.

But electrocardiography with a load has serious contraindications:

• hypertension of the third stage;
• severe circulatory disorders;
• thrombophlebitis in exacerbation;
• myocardial infarction in the acute period;
• enlargement of the walls of the heart;
• severe illness infectious nature.

You can not do a cardiogram with thrombophlebitis

Deciphering the results

Cardiograph data reflect the work of a vital organ and are the basis for making a diagnosis.

ECG analysis algorithm

The sequence of studying cardiac activity consists of several stages:

1. Evaluation of the work of the heart muscle - the rhythm and contraction of the organ. The study of intervals and the identification of blockades.
2. Assessment of ST segments and identification of abnormal Q waves.
3. The study of the teeth R.
4. Examination of the left and right ventricle in order to identify their hypertrophy.
5. The study of the location of the heart and the determination of its electrical axis.
6. Study of the T wave and other changes.

The electrocardiography analysis consists of 3 main indicators, which are schematically depicted on the cardiograph tape:

• teeth (elevations or depressions with sharp ends above a straight line);
• segments (segments connecting teeth);
• interval (distance consisting of a tooth and a segment).

When deciphering a cardiogram, parameters such as:

• systolic indicator - the amount of blood that is ejected by the ventricle for 1 contraction;
• minute indicator - the volume of blood passed through the ventricle in 1 minute;
• heart rate (HR) - the number of heartbeats in 60 seconds.

After analyzing all the characteristics, you can see the overall clinical picture cardiac activity.

ECG norm in adults

An inexperienced person will not be able to independently decipher the resulting scheme, but it is still possible to have a general idea of ​​\u200b\u200bthe state. To do this, it is necessary to understand the main characteristics of such monitoring within the normal range.

Table "Indicators of a good ECG"

How the main indicators of the activity of the heart look in the cardiogram is shown in the photo.

The norm of the cardiogram in children

Some ECG parameters in a child differ from adult indicators and depend on age:

1. Heart rate - from 135 (in a newborn baby) to 75-80 (in a teenager).
2. EOS (electrical axis of the heart) - normally, the total angle of the electric force vector should not exceed 45–70 degrees. In a newborn, the heart is deviated to the right; in children under 14 years old, the axis is vertical.
3. The rhythm of the heart is sinus.

The location and duration of the teeth correspond to the normal cardiogram of an adult.

Normal heart rate in a child

Any deviations from the norm in deciphering the cardiogram are the reason for a more detailed examination of the person.

There are several end results of the ECG:

• low-amplitude ECG - a decrease in the height of the teeth (QRS complex) in all leads - a common sign of myocardial dystrophy;
• borderline or atypical ECG - some parameters do not meet the standards, but do not belong to severe pathologies.
• pathological ECG - serious abnormalities in cardiac activity that require immediate medical attention.

Cardiogram with deviations

Not all changes in the cardiogram should be taken as an indicator of serious heart problems. Rhythm disturbances or a reduction in the width of the segments between the teeth in a healthy person may be the result of emotional overstrain, stress, and physical activity. In this case, it is better to go through monitoring again and double-check the results.

Table "Pathological disorders of cardiac activity"

This interpretation of the ECG makes it possible for an inexperienced person to roughly navigate the general scheme of the ECG. It is important to remember that only a specialist can read electrocardiography and draw appropriate conclusions. Therefore, you should not try to diagnose yourself.

Is it dangerous to do an EKG?

A classic heart cardiogram simply reads heart impulses and transfers them to paper. The device does not affect the heart or other organs. Therefore, the ECG does not pose a danger to children and adults. It can be safely done even to a newborn child and women during pregnancy.

Monitoring of cardiac activity using ECG allows you to quickly and reliably obtain an analysis of the state of the heart. Thanks to this method, it is possible to detect serious diseases of the cardiovascular system in a short time, check the effectiveness of drug treatment and identify diseases of other organs. Cardiography is completely safe for human health (only stress ECG has contraindications).

An electrocardiogram (ECG) is a record of the electrical activity of heart muscle cells at rest. Professional ECG analysis allows you to assess the functional state of the heart and identify most cardiac pathologies. But this study does not show some of them. In such cases, additional studies are prescribed. So, latent pathology can be detected when taking a cardiogram against the background of a stress test. Holter monitoring is even more informative - taking a round-the-clock cardiogram, as well as echocardiography.

When is an ECG ordered?

The cardiologist issues a referral if the patient has the following primary complaints:

• pain in the heart, back, chest, abdomen, neck;
• swelling in the legs;
• dyspnea;
• fainting;
• interruptions in the work of the heart.

With the sudden appearance sharp pains in the region of the heart, an ECG should be taken immediately!

Regular removal of a cardiogram is considered mandatory for such diagnosed diseases:

• previous heart attack or stroke;
• hypertension;
• diabetes;
• rheumatism.

Without fail, an ECG is performed in preparation for operations, monitoring pregnancy, medical examination pilots, drivers, sailors. The result of the cardiogram is often required when applying for a voucher for sanatorium treatment and issuing permits for active sports activities. For preventive purposes, even in the absence of complaints, it is recommended to take an ECG every year for everyone, especially people over 40 years old. Often this helps to diagnose asymptomatic heart disease.

The heart works tirelessly throughout life. Take care of it amazing organ without waiting for his complaints!

What does the ECG show

Visually, the cardiogram shows a combination of teeth and recessions. The teeth are sequentially designated by the letters P, Q, R, S, T. Analyzing the height, width, depth of these teeth and the duration of the intervals between them, the cardiologist gets an idea about the state of different parts of the heart muscle. So, the first P wave contains information about the work of the atria. The next 3 teeth represent the process of excitation of the ventricles. After the T wave, there is a period of relaxation of the heart.

An example of an ECG fragment with a normal sinus rhythm

The cardiogram allows you to determine:

• heart rate (HR);
• heart rate;
• various types of arrhythmias;
• various types of conduction blocks;
• myocardial infarction;
• ischemic and cardiodystrophic changes;
• Wolf-Parkinson-White syndrome (WPW);
• ventricular hypertrophy;
• the position of the electrical axis of the heart (EOS).

Diagnostic value of ECG parameters

heart rate

The heart of an adult human normally contracts from 60 to 90 times per minute. At a lower value, bradycardia is determined, and at a higher value, tachycardia, which is not necessarily a pathology. So, significant bradycardia is characteristic of trained athletes, especially runners and skiers, and transient tachycardia is quite normal with mental experiences.

In healthy adults, the pulse rate corresponds to the heart rate and is equal to 60 -90 for 1 minute

Heartbeat

A normal heart rhythm is called regular sinus, that is, generated in the sinus node of the heart. Non-sinus generation is pathological, and irregularity indicates one of the types of arrhythmia.

During the ECG, the patient is asked to hold their breath in order to identify a possible pathological non-respiratory arrhythmia. A serious problem is atrial fibrillation (atrial fibrillation). With it, the generation of cardiac impulses occurs not in the sinus node, but in the cells of the atria. As a result, the atria and ventricles contract randomly. This contributes to thrombosis and creates a real threat of heart attack and stroke. To prevent them, lifelong antiarrhythmic and antithrombotic therapy is prescribed.

Atrial fibrillation is a fairly common disease in old age. It may be asymptomatic, but pose a real threat to health and life. Follow your heart!

Arrhythmia also includes extrasystole. An extrasystole is an abnormal contraction of the heart muscle under the influence of an excess electrical impulse that does not originate from the sinus node. There are atrial, ventricular and atrioventricular extrasystoles. What types of extrasystoles require intervention? Single functional extrasystoles (usually atrial) often occur with a healthy heart against the background of stress or excessive physical exertion. Potentially dangerous include group and frequent ventricular extrasystoles.

blockades

Atrioventricular (A-V) blockade is a violation of the conduction of electrical impulses from the atria to the ventricles. As a result, they contract out of sync. A-V block usually requires treatment and, in severe cases, a pacemaker.

Impaired conduction within the myocardium is called bundle branch block. It can be localized on the left or right leg or on both together and be partial or complete. With this pathology, conservative treatment is indicated.

Sinoatrial blockade is a conduction defect from the sinus node to the myocardium. This type of blockade occurs with other heart diseases or with an overdose of drugs. Requires conservative treatment.

myocardial infarction

Sometimes an ECG reveals a myocardial infarction - necrosis of a section of the heart muscle due to a cessation of its blood circulation. The cause may be large atherosclerotic plaques or a sharp vasospasm. The type of infarction is distinguished by the degree of damage - small-focal (not Q-infarction) and extensive (transmural, Q-infarction) types, as well as localization. Detection of signs of a heart attack suggests urgent hospitalization of the patient.

ECG for myocardial infarction

The detection of scars on the cardiogram indicates a past myocardial infarction, possibly painless and unnoticed by the patient.

Ischemic and dystrophic changes

Ischemia of the heart is called oxygen starvation of its various parts due to insufficient blood supply. The detection of such a pathology requires the appointment of anti-ischemic drugs.

Dystrophic refers to metabolic disorders in the myocardium that are not associated with circulatory disorders.

Wolff-Parkinson-White syndrome

it congenital disease, which consists in the existence of abnormal conduction pathways in the myocardium. If this pathology causes arrhythmic attacks, then treatment is necessary, and in severe cases, surgical intervention.

Hypertrophy of the ventricles - an increase in size or thickening of the wall. Most often, hypertrophy is a consequence of heart defects, hypertension, lung diseases. The position of the EOS has no independent diagnostic value either. In particular, with hypertension, a horizontal position or deviation to the left is determined. The composition also matters. In thin people, as a rule, the position of the EOS is vertical.

Features of the ECG in children

For children under the age of one year, tachycardia up to 140 beats per minute, fluctuations in heart rate when taking an ECG, incomplete blockade of the right leg of the His bundle, vertical EOS are considered normal. At the age of 6 years, a heart rate of up to 128 beats per minute is acceptable. Respiratory arrhythmia is typical for the age of 6 to 15 years.

Electrocardiography or ECG of the heart is an examination during which the device senses the electrical activity of the heart. ECG results is a graph, usually written on graph paper as a curve, showing changes in voltage between two points over time.

Electrocardiography is a quick, cheap, and easy test for people that provides important information about heart function. Therefore, it belongs to the main medical examinations.

Many people know which doctor does an ECG. An electrocardiogram is done by a cardiologist, who also deciphers it. Today, cardiologist services are available online, where it is also possible to evaluate the results of the examination - that is, calmly go to the page - and decipher your cardiac activity!

Operating principle

The stimulus for contraction of any muscle cell is a change in tension between the internal and external environment of the cell. The same applies to the heart muscle, the cells of which must work very stably.

The initial electrical impulse is produced in specialized cells in the atrium cluster (sinus node), from where it is rapidly distributed throughout the heart so that the heart muscle contracts in a coordinated manner and effectively pushes blood out of the heart cavities.

When the heart muscle relaxes, the tension returns to its original state. These electrical changes during cardiac work propagate to the surface of the body (we are talking about millivolts), where they are scanned through the electrodes - this is a brief ECG description.

When and why is it carried out?

EKG is necessary examination with suspected heart disease. Electrocardiography is used in the diagnosis of ischemic changes in the heart muscle, i.e. changes from a lack of oxygen, the most serious manifestation of which is the death of heart cells due to a lack of oxygen - myocardial infarction.

In addition, an ECG analysis can show an arrhythmia - an abnormal heart rhythm.

The conclusion of the ECG also reveals the expansion of the heart in case of its insufficiency or pulmonary embolism. An ECG is usually performed as part of a preoperative examination before a planned procedure under general anesthesia or during a general examination.

Before the examination, there is no need to observe any special regime. Only peace is important.

Conducting an examination

In adults and children, the ECG is the same. The patient being examined must undress to the waist, if necessary, remove socks or stockings - must be accessible rib cage patient, ankle and wrist.

The examination is carried out in the supine position. The nurse or physician who performs the examination applies a small amount of conductive gel to the patient's skin, adult or child, to improve the transmission of electrical signals to the electrodes. Then the electrodes themselves are attached using rubber suction cups. There are also electrodes in the form of stickers (disposable), already impregnated with gel.

There are 10 electrodes in total: 6 on the chest and 1 on each limb. When all the electrodes are placed, the electrocardiograph turns on, and within a few seconds, the paper with the electrocardiographic curve leaves the device - the electrocardiography is completed.

ECG modification

There are several ways to measure the main indicators of the work of the heart:

• 24-hour Holter ECG monitoring;
• intermittent daily monitoring;
• load monitoring;
• esophageal monitoring.

24-hour Holter ECG monitoring

This examination is carried out mainly in adults; the subject wears the attached device for 24-48 hours. The electrodes are located on the chest, and the device is attached around the waist, the patient can work with it normally and perform any other normal activities.

This study is very important in diagnosing irregular heart rhythms that occur periodically, to confirm or rule out some problems associated with heart disease. The patient during the examination keeps a diary, and in case of manifestation of symptoms of the disease, independently records the time. The doctor can subsequently decipher the ECG in this time period.

This study is also practiced, mainly in an adult in the case of symptoms that occur less frequently. A person wears the device for longer than a day or two, activating it when difficulties arise.

Load monitoring

Usually called bicycle ergometry; examines the work of the heart under increased stress. The examination can be carried out both in adults and in children. The patient receives a load on the treadmill, at which time the device reflects his cardiac activity.

Esophageal monitoring

This is a less common examination performed on an empty stomach. An electrode is inserted into the esophagus through the mouth or nose. The electrode is thus very close to the left atrium, which provides a better waveform than a conventional recording and makes the ECG easier to read. It is used in cases where, with classical ECG interpretation was indefinite, or as a therapeutic method, when electrical stimulation provides a physiologically healthy rhythm.

Curve interpretation

Deciphering the cardiogram consists of 10 points:

• heartbeat;
• sinus rhythm;
• heart rate;
• P wave
• PQ interval;
• QRS complex;
• ST segment;
• T wave;
• QT interval;
• axis of the heart.

The following table provides norm indicators:

The norm in the table is indicated for adults. In children ECG norm the other varies with age.

The most important parameter in the question of how to decipher a cardiogram is the QRS complex, its shape and ECG waves. The basis of vibrations and deviations are changes in the electric field of the heart. Sinus arrhythmia on the ECG is characterized by irregular R-R intervals, i.e., QRS repetition.

The duration of the QRS complex is measured from the beginning of the Q wave to the end of the S wave, and indicates the duration of the contraction of the heart chamber. Normal ECG in this regard is 0.08-0.12 seconds. QRS shape healthy patient should be regular and constant.

In principle, the ideal ECG is constantly repeating QRS complexes at regular intervals, and the QRS has the same shape.

To decipher the cardiogram of the heart, in addition to manual reading, specialized software is used today. It not only decrypts the data, but also analyzes the signal. Modern methods are able to detect even the smallest pathological changes in the heart rhythm much more accurately.

Prong P

A physiological P wave precedes each QRS complex, from which it is separated by a PQ interval. The frequency of occurrence, therefore, coincides with the frequency of systole.

The positivity and negativity, the amplitude and duration of the P wave are evaluated:

• Positive and negative. Physiologically, the P wave in leads I and II is positive, in lead III it is positive or negative. Negative P in lead I or II is pathological.
• Amplitude. In normal mode, the amplitude of the P wave does not exceed 0.25 mV. Higher values ​​indicate hypertrophy.
• The duration of the P wave does not exceed 0.11 sec. Elongation indicates atrial dilatation, the wave is called P mitrale, and is typical of mitral valve stenosis.

PQ interval

The PQ interval corresponds to atrial systole and air retention in the AV node. It is measured from the beginning of the P wave to the beginning of the ventricular complex. Normal values– from 0.12 to 0.20 seconds.

Pathology:

• a prolonged PQ interval occurs in AV node blocks;
• a shortened PQ interval indicates pre-excitation syndrome (air bypasses the AV node via parallel connections).

If the P wave does not contain a cardiac ECG, no decoding of the PQ interval is performed (the same applies if the P wave does not depend on the QRS complex).

QRS complex

The QRS complex represents contraction of the ventricular heart muscle:

• Q - the first negative oscillation, may be absent;
• R is each positive swing. Usually only one is present. If there is more than 1 vibration of R in the complex, it is indicated by an asterisk (for example, R*);
• S - each negative swing after at least one R. More swings are denoted similarly to R.

Three factors are evaluated on the QRS complex:

• duration;
• presence and duration of Q;
• Sokolov indices.

If LBBB is detected after a general ECG evaluation, the Sokolov indices are not measured.

QRS indicators:

• QRS duration. The physiological duration of the QRS complex is up to 0.11 s. Pathological prolongation up to 0.12 s. may indicate incomplete blockade, myocardial infarction, and ventricular hypertrophy. Extension over 0.13 s. indicates LBBB.
• Q fluctuations. In all conclusions, Q fluctuations are determined. They are usually present. However, their duration does not exceed 0.03 s. The only exception is the aVR oscillation, in which Q is not abnormal.

Q is longer than 0.04 s. clearly shows the scar after myocardial infarction. According to their individual fluctuations, it is possible to determine the location of the infarction (anterior wall, septal, diaphragmatic).

Sokolov indices (Sokolov-Lyon criteria for ventricular hypertrophy)

From the size of the amplitude of the QRS fluctuations, one can approximately determine the thickness of the chamber wall. For this, Sokolov indices are used, 1 for the right and 2 for the left ventricle.

Indicators for the right ventricle:

• the sum of the amplitudes of the P wave in the leads V1, S and in the lead V6, usually does not exceed 1.05 mV;
• normal values: R (V1) S + (V6)<1,05 мВ;
• right ventricular hypertrophy on ECG: ≥ 1.05 mV.

To determine left ventricular hypertrophy, there are 2 Sokolov indices (LK1, LK2). In this case, the amplitudes are also summed, but in the S wave in the V1 tap and in the R wave in the V5 or V6 taps.

• LK1: S (V1) + R (V5)<3,5 мВ (норма);
• LK2: S (V1) + R (V6)<4 мВ (норма).

If the measured values ​​exceed the norm, they are marked as pathological. The following indicators indicate left ventricular hypertrophy:

• LK1: S (V1) + R (V5) > 3.5 mV;
• LK2: S (V1) + R (V6) > 4mV.

T wave

The T wave on the ECG represents repolarization of the ventricular myocardium and is physiologically concordant. Otherwise, it is described as discordant, being pathological. The T wave is described in leads I, II, and III, in aVR, and in thoracic leads V3-V6.

• I and II - positive concordat;
• III - concordat (polarity does not matter);
• aVR - negative T wave on the ECG;
• V3-V6 - positive.

Any deviation from the norm is pathological. Sometimes the T wave is bipolar, in which case it is described as preterminally negative (-/+) or terminally negative (+/-).

T wave deviations occur with myocardial hypoxia.

A tall T wave (i.e. gothic) is typical of an acute heart attack.

QT interval

The distance from the beginning of the ventricular QRS complex to the end of the T wave is measured. Normal values ​​​​are 0.25-0.50 s. Other values ​​indicate an error in the examination itself or in the evaluation of the ECG.

Research results

The result of the study is available immediately, then its assessment depends on the doctor (ECG interpretation). It can determine if the heart is suffering from a lack of oxygen, if it is working at the correct rhythm, if the number of beats per minute is correct, etc.

Some heart conditions, however, may not be detected by an ECG. These include, for example, arrhythmia, which manifests itself periodically, or a violation of cardiac activity during any physical activity. If such a cardiac disorder is suspected, the doctor should perform some additional tests.