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Cardiovascular diseases are one of the leading causes of death among people worldwide. Behind last decades this figure has decreased significantly due to the advent of more modern methods of examination, treatment, and, of course, new medications.

Electrocardiography (ECG) is a method of recording the electrical activity of the heart, one of the first research methods that long time remained practically alone in this field of medicine. About a century ago in 1924, Willem Einthoven received Nobel Prize in medicine, he designed a device with which the ECG was recorded, gave names to its teeth and identified the electrocardiographic signs of some heart diseases.

Many research methods are losing their relevance with the advent of more modern developments, but this does not apply to electrocardiography. Even with the advent of imaging techniques (CT, CT, etc.), the ECG for decades continues to be the most common, very informative, and in some places the only available method for studying the heart. Moreover, over the century of its existence, neither the device itself nor the method of its use have changed significantly.

Indications and contraindications

Electrocardiography is a unique examination method that helps make a diagnosis or becomes Starting point to draw up a plan for further examination of the patient. In any case, the diagnosis and treatment of any heart disease begins with an ECG.

An ECG is an absolutely safe and painless method of examination for people of all ages; there are no contraindications to conventional electrocardiography. The study takes only a few minutes and does not require any special preparation.

But there are so many indications for electrocardiography that it is simply impossible to list them all. The main ones are the following:

• general examination during medical examination or medical commission;
• assessment of the state of the heart in various diseases (atherosclerosis, lung diseases, etc.);
• differential diagnosis for chest pain and (often have a non-cardiac cause);
• suspicion of, as well as control of the course of this disease;
• diagnosis of heart rhythm disorders (24-hour Holter ECG monitoring);
• disturbance of electrolyte metabolism (hyper- or hypokalemia, etc.);
• overdose of drugs (for example, cardiac glycosides or antiarrhythmic drugs);
• diagnosis of non-cardiac diseases (pulmonary embolism), etc.

The main advantage of an ECG is that the study can be performed outside a hospital; many ambulances are equipped with electrocardiographs. This allows the doctor at the patient’s home to detect myocardial infarction at its very beginning, when damage to the heart muscle is just beginning and is partially reversible. After all, treatment in such cases begins while the patient is being transported to the hospital.

Even in cases where the emergency room is not equipped with this device and the emergency doctor does not have the opportunity to perform the study at the prehospital stage, the first diagnostic method in the emergency room of a medical institution will be an ECG.

Interpretation of ECG in adults

In most cases, cardiologists, therapists, and emergency doctors work with electrocardiograms, but a specialist in this field is a functional diagnostics doctor. Interpreting an ECG is not an easy task, which is beyond the power of a person who does not have the appropriate qualifications.

Typically, on the ECG of a healthy person, five waves can be distinguished, recorded in a certain sequence: P, Q, R, S and T, sometimes a U wave is recorded (its nature is not exactly known today). Each of them reflects the electrical activity of the myocardium in different parts of the heart.

When recording an ECG, several complexes corresponding to heart contractions are usually recorded. In a healthy person, all the teeth in these complexes are located at the same distance. The difference in the intervals between complexes indicates.

In this case, in order to accurately determine the form of the arrhythmia, Holter ECG monitoring may be necessary. Using a special small portable device, the cardiogram is recorded continuously for 1-7 days, after which the resulting recording is processed using a computer program.

• The first P wave reflects the process of depolarization (excitation coverage) of the atria. Based on its width, amplitude and shape, the doctor can suspect hypertrophy of these chambers of the heart, a disturbance in the conduction of impulses through them, and suggest that the patient has organ defects and other pathologies.
• The QRS complex reflects the process of excitation of the ventricles of the heart. Deformation of the shape of the complex, a sharp decrease or increase in its amplitude, the disappearance of one of the teeth can indicate a variety of diseases: myocardial infarction (with the help of an ECG you can determine its location and duration), scars, conduction disorders (bundle branch block), etc.
• The last T wave is determined by ventricular repolarization (relatively speaking, relaxation); deformation of this element can indicate electrolyte disturbances, ischemic changes and other heart pathologies.

The ECG sections connecting different waves are called “segments”. Normally, they lie on the isoline, or their deviation is not significant. Between the teeth there are intervals (for example, PQ or QT), which reflect the time of passage of the electrical impulse through the parts of the heart; in a healthy person they have a certain duration. Lengthening or shortening of these intervals is also a significant diagnostic sign. Only a qualified doctor can see and evaluate all changes on the ECG.

In deciphering an ECG, every millimeter is important, sometimes even half a millimeter is decisive in choosing treatment tactics. Very often, an experienced doctor can make an accurate diagnosis using an electrocardiogram without the use of additional research methods, and in some cases its information content exceeds the data of other types of research. In essence, this is a screening method of examination in cardiology, which allows one to identify or at least suspect heart disease in the early stages. That's why the electrocardiogram is still long years will remain one of the most popular diagnostic methods in medicine.

Which doctor should I contact?

For a referral for an ECG, you need to contact a physician or cardiologist. The analysis of the cardiogram and the conclusion on it are given by a functional diagnostics doctor. The ECG report itself is not a diagnosis and must be considered by the clinician in combination with other data about the patient.

Basics of electrocardiography in educational video:

Video course “Everyone can do an ECG”, lesson 1:

Video course “Everyone can do an ECG”, lesson 2.

An electrocardiogram is a diagnostic method that allows you to determine the functional state of the most important organ of the human body - the heart. Most people have dealt with such a procedure at least once in their lives. But having received the ECG result, not every person, unless he has a medical education, will be able to understand the terminology used in cardiograms.

What is cardiography

The essence of cardiography is the study of electrical currents arising during the work of the heart muscle. The advantage of this method is its relative simplicity and accessibility. Strictly speaking, a cardiogram is the result of measuring the electrical parameters of the heart, displayed in the form of a time graph.

Creation of electrocardiography in its modern form is associated with the name of the Dutch physiologist of the early 20th century, Willem Einthoven, who developed the basic ECG methods and terminology used by doctors to this day.

Thanks to the cardiogram, it is possible to obtain the following information about the heart muscle:

• Heart rate,
• Physical condition of the heart
• The presence of arrhythmias,
• The presence of acute or chronic myocardial damage,
• The presence of metabolic disorders in the heart muscle,
• Presence of electrical conductivity disturbances,
• Position of the electrical axis of the heart.

Also, a cardiac electrocardiogram can be used to obtain information about certain vascular diseases not related to the heart.

An ECG is usually performed in the following cases:

• Feeling of abnormal heartbeat;
• Attacks of shortness of breath, sudden weakness, fainting;
• Heartache;
• Heart murmurs;
• Deterioration of the condition of patients with cardiovascular diseases;
• Passing medical examinations;
• Medical examination of people over 45 years of age;
• Examination before surgery.

• Pregnancy;
• Endocrine pathologies;
• Nervous diseases;
• Changes in blood counts, especially with an increase in cholesterol;
• Over 40 years of age (once a year).

Where can I get a cardiogram?

If you suspect that there is something wrong with your heart, you can contact a therapist or cardiologist so that he can give you a referral for an ECG. Also, for a fee, a cardiogram can be done in any clinic or hospital.

Methodology of the procedure

ECG recording is usually performed in a supine position. To take a cardiogram, a stationary or portable device is used - an electrocardiograph. Stationary devices are installed in medical institutions, and portable ones are used by emergency teams. The device receives information about electrical potentials on the surface of the skin. For this purpose, electrodes are used that are attached to the chest area and limbs.

These electrodes are called leads. There are usually 6 leads installed on the chest and limbs. The chest leads are designated V1-V6, the leads on the limbs are called basic (I, II, III) and reinforced (aVL, aVR, aVF). All leads give several different picture oscillations, however, by summing up the information from all electrodes, it is possible to find out the details of the work of the heart as a whole. Sometimes additional leads are used (D, A, I).

Typically, the cardiogram is displayed in the form of a graph on paper containing millimeter markings. Each electrode lead has its own schedule. The standard speed of the belt is 5 cm/s; other speeds may be used. The cardiogram displayed on the tape can also indicate the main parameters, normal indicators and a conclusion generated automatically. Data can also be recorded in memory and on electronic media.

After the procedure, the cardiogram is usually deciphered by an experienced cardiologist.

Holter monitoring

In addition to stationary devices, there are also portable devices for daily (Holter) monitoring. They are attached to the patient's body along with electrodes and record all information received over a long period of time (usually within 24 hours). This method gives much more full information about processes in the heart in comparison with a regular cardiogram. For example, when taking a cardiogram in a hospital setting, the patient must be at rest. Meanwhile, some deviations from the norm may appear during physical activity, sleep, etc. Holter monitoring provides information about such phenomena.

Other types of procedures

There are several other methods for carrying out the procedure. For example, this is monitoring with physical activity. Abnormalities are usually more pronounced on the stress ECG. The most common way to provide the body with the necessary physical activity is treadmill. This method is useful in cases where pathologies can only manifest themselves in the case of increased heart function, for example, if coronary artery disease is suspected.

During phonocardiography, not only the electrical potentials of the heart are recorded, but also the sounds that arise in the heart. The procedure is prescribed when it is necessary to clarify the occurrence of a heart murmur. This method often used when heart defects are suspected.

It is necessary that the patient remains calm during the procedure. A certain period of time must pass between physical activity and the procedure. It is also not recommended to undergo the procedure after eating, drinking alcohol, caffeinated drinks, or cigarettes.

Reasons that can affect the ECG:

• Times of Day,
• Electromagnetic background,
• Physical exercise,
• Eating,
• Electrode position.

Types of teeth

First we should talk a little about how the heart works. It has 4 chambers - two atria and two ventricles (left and right). The electrical impulse, due to which it contracts, is formed, as a rule, in the upper part of the myocardium - in the sinus pacemaker - the sinoatrial (sinus) node. The impulse spreads down the heart, first affecting the atria and causing them to contract, then passes through the atrioventricular nerve node and another nerve node, the bundle of His, and reaches the ventricles. The main burden of pumping blood is taken on by the ventricles, especially the left one, which is involved in big circle blood circulation This stage is called heart contraction or systole.

After contraction of all parts of the heart, the time comes for their relaxation - diastole. The cycle then repeats again and again - this process is called heartbeat.

The condition of the heart, in which there are no changes in the propagation of impulses, is reflected on the ECG in the form of a straight horizontal line, called an isoline. The deviation of the graph from the isoline is called a spike.

One heartbeat on the ECG contains six waves: P, Q, R, S, T, U. The waves can be directed both up and down. In the first case they are considered positive, in the second - negative. The Q and S waves are always positive, and the R wave is always negative.

The teeth reflect the different phases of heart contraction. P reflects the moment of contraction and relaxation of the atria, R – excitation of the ventricles, T – relaxation of the ventricles. Special designations are also used for segments (spaces between adjacent teeth) and intervals (sections of the graph that include segments and teeth), for example, PQ, QRST.

Correspondence between the stages of heart contraction and some elements of cardiograms:

• P – atrial contraction;
• PQ horizontal line, transition of the discharge from the atria through the atrioventricular node to the ventricles. The Q wave may be absent normally;
• QRS – ventricular complex, the element most often used in diagnostics;
• R – ventricular excitation;
• S – myocardial relaxation;
• T – ventricular relaxation;
• ST – horizontal line, myocardial recovery;
• U – may be absent normally. The reasons for the appearance of the prong are not clearly understood, but the prong is valuable for diagnosing certain diseases.

Below are some abnormal ECG findings and their possible explanations. This information, of course, does not negate the fact that it is more advisable to entrust the decoding to a professional cardiologist who better knows all the nuances of deviations from the norm and associated pathologies.

Main deviations from the norm and diagnosis

Table of cardiogram parameters in adults

Normal duration of cardiogram elements in children

The norms indicated in the table may also depend on age.

Rhythm of contractions

Violation of the rhythm of contractions is called. The irregularity of the rhythm during arrhythmia is measured as a percentage. An irregular rhythm is indicated by a deviation in the distance between similar teeth by more than 10%. Sinus arrhythmia, that is, arrhythmia combined with sinus rhythm, may be normal for adolescents and young adults, but in most cases it indicates the onset of a pathological process.

A type of arrhythmia is extrasystole. They say it in the case when extraordinary contractions are observed. Single extrasystoles (no more than 200 per day with Holter monitoring) can also be observed in healthy people. Frequent extrasystoles that appear on the cardiogram in the amount of several pieces may indicate ischemia, myocarditis, or heart defects.

Heart rate

This option is the simplest and most understandable. It determines the number of contractions in one minute. The number of contractions may be higher than normal (tachycardia) or lower than normal (bradycardia). The normal heart rate in adults can range from 60 to 80 beats. However, the norm in in this case The concept is relative, so bradycardia and tachycardia may not always be evidence of pathology. Bradycardia can be observed during sleep or in trained people, and tachycardia - during stress, after physical activity or at elevated temperatures.

Heart rate norms for children of different ages

Photo: Africa Studio/Shutterstock.com

Heart Rate Types

There are several types of heart rhythm, depending on where the nerve impulse begins to spread, causing the heart to contract:

• Sinus,
• Atrial,
• Atrioventricular,
• Ventricular.

Normally, the rhythm is always sinus. In this case, sinus rhythm can be combined with both a heart rate above normal and a heart rate below normal. All other types of rhythms are evidence of problems with the heart muscle.

Atrial rhythm

Atrial rhythm also often appears on the cardiogram. Is atrial rhythm normal or is it a type of pathology? In most cases, the atrial rhythm on the ECG is not normal. However, this is comparatively mild degree heart rhythm disturbances. It occurs when the sinus node is suppressed or disrupted. Possible causes are ischemia, hypertension, sick sinus syndrome, endocrine disorders. However, isolated episodes of atrial contractions can also be observed in healthy people. This type of rhythm can take on both the character of bradycardia and the character of tachycardia.

Atrioventricular rhythm

Rhythm emanating from the atrioventricular node. With atrioventricular rhythm, the pulse rate usually drops to less than 60 beats per minute. Causes: weakness of the sinus node, atrioventricular block, taking certain medications. Atrioventricular rhythm, combined with tachycardia, can occur during heart surgery, rheumatism, and heart attack.

Ventricular rhythm

With ventricular rhythm, contractile impulses propagate from the ventricles. The contraction frequency drops to below 40 beats per minute. The most severe form of rhythm disturbance. Occurs in acute infarction, heart defects, cardiosclerosis, cardiac circulatory failure, and in a preagonal state.

Electrical axis of the heart

One more important parameter is the electrical axis of the heart. It is measured in degrees and reflects the direction of propagation of electrical impulses. Normally, it should be slightly inclined to the vertical and be 30-69º. At an angle of 0-30º the axis is said to be horizontal, and at an angle of 70-90º it is said to be vertical. Deviation of the axis in one direction or another may indicate a disease, for example, hypertension or intracardiac blockades.

What do the conclusions on cardiograms mean?

Let's look at some terms that an ECG transcript may contain. They do not always indicate serious pathologies, but in any case they require a visit to a doctor for advice, and sometimes additional examinations.

Photo: Have a nice day Photo/Shutterstock.com

Atrioventricular block

It is reflected on the graph as an increase in the duration of the P-Q interval. Stage 1 disease is reflected in the form of a simple prolongation of the interval. Grade 2 is accompanied by deviation of QRS parameters (loss of this complex). At grade 3, there is no connection between P and the ventricular complex, which means that the ventricles and atria each work in their own rhythm. The syndrome in stages 1 and 2 is not life-threatening, but requires treatment, as it can progress to the extremely dangerous stage 3, in which there is a high risk of cardiac arrest.

Ectopic rhythm

Any heart rhythm that is not sinus. It may indicate the presence of blockades, coronary heart disease, or be a variant of the norm. It can also appear as a result of an overdose of glycosides, neurocirculatory dystonia, and hypertension.

Sinus bradycardia or tachycardia

Sinus rhythm on the ECG, the frequency of which is below (bradycardia) or above (tachycardia) the normal limits. It can be either a variant of the norm or a symptom of certain pathologies. However, in the latter case, this symptom will most likely not be the only one indicated in the transcript of the cardiogram.

Nonspecific ST-T changes

What it is? This entry suggests that the reasons for the interval change are unclear and further research is required. It may indicate a disturbance in metabolic processes in the body, for example a change in the balance of potassium, magnesium, sodium ions or endocrine disorders.

Disorders associated with conduction within the ventricles

As a rule, they are associated with conduction disturbances within the His nerve bundle. May affect the beam trunk or its legs. May lead to a delay in the contraction of one of the ventricles. Direct therapy for His bundle blockades is not carried out; only the disease that caused them is treated.

Incomplete right bundle branch block (RBBB)

Common ventricular conduction disorder. In most cases, however, it does not lead to the development of pathologies and is not their consequence. If the patient has no problems with cardiovascular system, then this symptom does not require treatment.

Complete right bundle branch block (RBBB)

This violation is more serious compared to incomplete blockade. May indicate myocardial damage. Usually occurs in older and older people; it is rarely found in children and adolescents. Possible symptoms are shortness of breath, dizziness, general weakness and fatigue.

Block of the anterior branch of the left bundle branch (ALBBB)

Occurs in patients with hypertension who have had a heart attack. It may also indicate cardiomyopathies, cardiosclerosis, atrial septal defect, and mitral valve insufficiency. Has no characteristic symptoms. It is observed mainly in older people (over 55 years old).

Block of the posterior branch of the left bundle branch (B3VLBP)

As a separate symptom, it is rare; as a rule, it is combined with a blockade of the right bundle branch. May indicate a heart attack, cardiosclerosis, cardiomyopathy, or calcification of the conduction system. A blockade is indicated by a deviation in the electrical axis of the heart to the right.

Metabolic changes

Reflects nutritional disorders of the heart muscle. First of all, this concerns the balance of potassium, magnesium, sodium and. The syndrome is not an independent disease, but indicates other pathologies. Can be observed with ischemia, cardiomyopathy, hypertension, rheumatism, cardiosclerosis.

Low voltage ECG

Electrodes installed on the patient's body detect currents of a certain voltage. If the voltage parameters are below normal, then they speak of low voltage. This indicates insufficient external electrical activity of the heart and may be a consequence of pericarditis or a number of other diseases.

Paroxysmal tachycardia

A rare condition that differs from ordinary (sinus) tachycardia, first of all, in that it involves a very high heart rate - more than 130 beats per second. In addition, paroxysmal tachycardia is based on improper circulation of the electrical impulse in the heart.

Atrial fibrillation

Atrial fibrillation is based on atrial fibrillation or flutter. Arrhythmia caused by atrial fibrillation can occur in the absence of heart pathologies, for example, with diabetes, intoxication, and smoking. Atrial flutter may be characteristic of cardiosclerosis, some types of ischemic disease, and inflammatory processes of the myocardium.

Sinoatrial blockade

Difficulty in the exit of an impulse from the sinus (sinoatrial) node. This syndrome is a type of sick sinus syndrome. It is rare, mainly in older people. Possible causes are rheumatism, cardiosclerosis, calcinosis, severe hypertension. May lead to severe bradycardia, fainting, convulsions, and breathing problems.

Hypertrophic conditions of the myocardium

They indicate an overload of certain parts of the heart. The body feels this situation and responds to it by thickening the muscle walls of the corresponding section. In some cases, the causes of the condition may be hereditary.

Myocardial hypertrophy

General myocardial hypertrophy is defensive reaction, indicating excessive strain on the heart. May lead to arrhythmia or heart failure. Sometimes it is a consequence of a heart attack. A type of disease is hypertrophic cardiomyopathy, a hereditary disease that leads to abnormal alignment of heart fibers and carries the risk of sudden cardiac arrest.

Left ventricular hypertrophy

The most common symptom, which does not always indicate severe heart pathologies. May be characteristic of arterial hypertension, obesity, and some heart defects. Sometimes it is observed in trained people, people engaged in heavy physical labor.

Right ventricular hypertrophy

A rarer, but at the same time much more dangerous symptom than left ventricular hypertrophy. Indicates pulmonary circulatory failure, severe pulmonary diseases, valve defects or severe heart defects (tetralogy of Fallot, ventricular septal defect).

Left atrial hypertrophy

Reflected as a change in the P wave on the cardiogram. With this symptom, the tooth has a double peak. Indicates mitral or aortic stenosis, hypertension, myocarditis, cardiomyopathies. Leads to chest pain, shortness of breath, increased fatigue, arrhythmias, and fainting.

Right atrial hypertrophy

Less common than left atrial hypertrophy. It can have many causes - pulmonary pathologies, chronic bronchitis, arterial embolism, tricuspid valve defects. Sometimes observed during pregnancy. May lead to circulatory problems, swelling, and shortness of breath.

Normocardia

Normocardia or normosystole means normal heart rate. However, the presence of normosystole in itself does not indicate that the ECG is normal and everything is in order with the heart, since it may not exclude other pathologies, such as arrhythmias, conduction disorders, etc.

Nonspecific T wave changes

This symptom is typical for approximately 1% of people. A similar conclusion is made if it cannot be unambiguously associated with any other disease. Thus, for nonspecific T wave changes, additional studies are necessary. The sign may be characteristic of hypertension, ischemia, anemia and some other diseases, and may also occur in healthy people.

Tachysystole

Also often called tachycardia. This is the general name for a number of syndromes in which there is an increased frequency of contractions of various parts of the heart. There are ventricular, atrial, and supraventricular tachysystoles. Such types of arrhythmias as paroxysmal tachycardia, atrial fibrillation and flutter also belong to tachysystoles. In most cases, tachysystoles are a dangerous symptom and require serious treatment.

Heart ST depression

ST segment depression is common in high-frequency tachycardias. It often indicates a lack of oxygen supply to the heart muscle and may be characteristic of coronary atherosclerosis. At the same time, the appearance of depression is also observed in healthy people.

Borderline ECG

This conclusion often frightens some patients who have detected it on their cardiograms and are inclined to think that “borderline” means almost “deathbed.” In fact, such a conclusion is never given by a doctor, but is generated by a program that analyzes the parameters of the cardiogram on an automatic basis. Its meaning is that a number of parameters are outside the normal range, but it is impossible to unambiguously draw a conclusion about the presence of some kind of pathology. Thus, the cardiogram is on the border between normal and pathological. Therefore, when receiving such a conclusion, a doctor’s consultation is required, and perhaps everything is not so scary.

Pathological ECG

What it is? This is a cardiogram on which some serious deviations from the norm were clearly detected. These may be arrhythmias, conduction or nutritional disorders of the heart muscle. Pathological changes require immediate consultation with a cardiologist, who should indicate a treatment strategy.

Ischemic changes on the ECG

Coronary artery disease is caused by impaired circulation in the coronary vessels of the heart and can lead to such serious consequences as myocardial infarction. Therefore, identifying ischemic signs on an ECG is very important task. Early ischemia can be diagnosed by changes in the T wave (rising or falling). At a later stage, changes in the ST segment are observed, and at an acute stage, changes in the Q wave are observed.

Interpretation of ECG in children

In most cases, deciphering a cardiogram in children is not difficult. But the normal parameters and the nature of the disorders may differ compared to similar indicators in adults. So, children normally have a much faster heartbeat. In addition, the sizes of the teeth, intervals and segments are slightly different.

ECG is considered one of the most common and informative diagnostic methods. With its help, a variety of cardiac pathologies are identified, and the effectiveness of treatment is also monitored. But what does an ECG of the heart show and how often can it be done? We will talk about its features below.

What is ECG

Electrocardiography is a method of examining the electrophysiological functioning of the heart muscle. Used for diagnosis special apparatus, registering the slightest changes in its activity, and then displaying them in graphic representation. Conduction, contraction frequency, hypertrophic changes, scarring and other changes in myocardial function can all be detected using an ECG.

During the diagnostic process, special electrodes record the contraction of the heart, namely the bioelectric potentials that arise. Electrical excitation covers different parts of the heart muscle in different time, therefore, a potential difference is fixed between the unexcited and excited sections. It is this data that is captured by electrodes placed on the body.

The video below will tell you about the indicators and features of the ECG in a simple and accessible form:

Who is it prescribed to?

ECG is used to diagnose a number of cardiac abnormalities. So, the indications for prescribing the procedure are:

1. Scheduled examination. Necessary for different categories of people, including adolescents, pregnant women, athletes, before surgical interventions or in the presence of any diseases (pulmonary and gastrointestinal diseases, thyroid gland, diabetes).
2. For the diagnosis of secondary or primary diseases as a preventive measure or to identify possible complications.
3. Carrying out monitoring during the treatment period or after its completion if any diseases are detected.

An electrocardiogram is performed if there are indications for using this diagnostic method. It is also required when undergoing a medical examination of drivers, the draft board, or when being sent for treatment to a sanatorium. For pregnant women, the test is done at least 2 times: at the time of registration and before giving birth.

Why do it?

Diagnostics helps determine early stages cardiac dysfunction, as well as prerequisites for the development of serious pathologies. An electrocardiogram is capable of detecting the slightest changes occurring in the heart: thickening of its walls, changes in the normal dimensions inside its cavities, and its location, size, etc. This greatly affects the accuracy of the prognosis and the selection of appropriate treatment, not to mention the importance of timely prevention.

Doctors note that those who have celebrated their fortieth birthday require an annual scheduled examination, even in the absence of objective symptoms and prerequisites for cardiac problems. This is explained by the increasing risk of complications in the functioning of the main “motor” of the body with age. In other cases, it is enough to visit a doctor for this procedure once every 1-2 years.

Types of diagnostics

There are several methods and types of electrocardiographic examination of the heart (ECG):

• At rest. Standard method used in most cases. If the diagnosis at this stage does not provide accurate data, they resort to other types of ECG.
• With load. This type of examination involves the use of physical (bicycle ergometry, treadmill test) or medicinal load. This also includes inserting a sensor through the esophagus to electrically stimulate the heart. This technique makes it possible to identify diseases that are not detected at rest.
• . A small device is installed in the chest area, which monitors cardiac activity throughout the day. Heart function is recorded during everyday activities, which is one of the advantages of the study.
• Transesophageal ECG performed with low information content of electrocardiography through the chest wall.

Indications for testing

You should contact the clinic for an examination if:

• complaints of pain in the thoracic region, including the spine;
• over 40 years of age;
• episodes of varying degrees and intensity of pain in the heart, especially those arising from temperature changes;
• shortness of breath;
• chronic respiratory system diseases;
• , and a number of other cardiac pathologies;
• fainting, episodes of increased heart rate, dizziness, disruption of the heart muscle.

A specialist will tell you about the indications for the ECG procedure in the video below:

Contraindications for

There are no special contraindications that could cause refusal to perform an ECG. Difficulties in carrying out the procedure are observed only in certain categories of citizens ( high degree hair growth, obesity, chest trauma). The data is distorted in persons with an installed pacemaker.

There are a number of contraindications for performing a stress ECG (an electrocardiogram is performed under load):

1. worsening the course of existing diseases,
2. myocardial infarction in the acute period,
3. acute infections,
4. (heavy).

If a transesophageal ECG is necessary, then contraindications are, accordingly, pathologies of the esophagus.

Safety of the procedure

The cardiogram is completely safe, even for pregnant women. It never gives any complications, including those related to the development of the child.

How to prepare for a cardiac ECG

No special preparation is required before the test.

• You can take food and water without restricting yourself in front of it.
• But you should give up energy drinks, including coffee.
• It is also better to leave cigarettes and alcohol aside before the examination so as not to distort the data.

How does the session work?

To conduct an electrocardiogram, you do not need to be in a hospital; you just need to visit a clinic. In case of emergency hospitalization, the initial examination can be carried out immediately on the spot, which will allow the ambulance team to effectively help the victim.

1. In the diagnostic room, the patient must take a supine position on the couch.
2. To ensure good conductivity, skin areas on the chest, ankles and hands are wiped with a damp sponge.
3. After this, a pair of electrodes in the form of clothespins are placed on the arms and legs, and 6 “suction cups” are placed on the left chest area in the projection of the heart.
4. After this preparation, the device turns on and the electrical activity of the heart muscle begins to be recorded on a special thermal film in the form of a graphic curve. Sometimes the result goes through the device directly to the doctor’s computer.

Throughout the entire period of the study, which usually lasts no longer than 10 minutes, the patient does not feel any discomfort, everything passes in a calm state and without discomfort. After this, all that remains is to wait for the received data to be decrypted. This procedure is also performed by a doctor, and then he transmits the results to the treating doctor’s office or directly into the hands of the visitor. If pathologies requiring immediate treatment are identified, he may be sent to a hospital, but if there are none, the patient is sent home.

Read on to learn how to decipher an ECG of the heart.

Results and their interpretation

After receiving the results of the study, it is necessary to decipher the cardiac electrocardiography (ECG) indicators in children and adults. The result of the cardiogram includes several main components:

• Segments ST, QRST, TP- this is the name of the distance located between the nearest teeth.
• Prongs- these are acute angles, including those directed downwards. These include the designations R, QS, T, P.
• Interval. It includes the entire segment and tooth. This is PQ, that is, the interval, the period of passage of the impulse from the ventricles to the atria.

The cardiologist analyzes these components; they also help determine the time of contraction and excitation of the myocardium. An ECG can determine the approximate location of an organ in the chest, which is possible due to the presence of an electrical axis.

Electrocardiography or ECG of the heart is a test in which a device senses the electrical activity of the heart. ECG results are 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 tells important information about the function of the heart. Therefore, it belongs to the basic medical examinations.

Many people know which doctor does an ECG. An electrocardiogram is performed by a cardiologist, who also interprets 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, whose cells 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 cavities of the heart.

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

When and why is it carried out?

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

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

Conclusion The ECG also reveals expansion of the heart when it is insufficient or. A cardiogram is usually performed as part of a preoperative examination before a planned procedure under general anesthesia, or as part of a general examination.

Before the examination there is no need to comply with any special regime. All that matters is calmness.

Carrying out an examination

The ECG is the same for adults and children. The patient undergoing the examination should undress to the waist, if necessary, remove socks or stockings - the patient's chest, ankles and wrists should be accessible.

The examination is carried out in a lying position. The nurse or doctor performing the examination applies a small amount of conductive gel to the skin of the patient, 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 a total of 10 electrodes: 6 on the chest and 1 on each limb. When all electrodes are placed, the electrocardiograph is turned on, and within a few seconds the paper with the electrocardiographic curve comes out of the device - the electrocardiography is completed.

ECG modification

There are several ways to measure basic heart indicators:

• intermittent daily monitoring;
• load monitoring;
• esophageal monitoring.

24-hour Holter ECG monitoring

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

This test is very important in diagnosing heart rhythm disturbances that occur periodically, to confirm or rule out certain problems associated with heart disease. The patient keeps a diary during the examination, and if symptoms of the disease appear, he independently records the time. The doctor can subsequently interpret the ECG in this time period.

This test is also used primarily in adults for symptoms that occur less frequently. The 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 load. The examination can be carried out in both adults and children. The patient receives exercise on a treadmill, while the device reflects his cardiac activity.

Esophageal monitoring

This is a less common examination, performed on an empty stomach. The patient has an electrode 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, making the ECG easier to read. It is used in cases where the interpretation of the classical ECG was unclear, or as a therapeutic method when electrical stimulation provides a physiological healthy rhythm.

Decoding the curve

Decoding 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 the norm indicators:

The norm in the table is indicated for adults. In children, the ECG norm is different and varies depending on age-related changes.

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 electric field hearts. ECG is characterized by irregular R-R intervals, i.e., repeating the QRS.

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 contraction of the cardiac chamber. A normal ECG in this regard is 0.08-0.12 seconds. The QRS shape in a healthy patient should be regular and constant.

In principle, the ideal cardiogram 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, today a specialized software. It not only decrypts the data, but also analyzes the signal. Modern methods are able to detect even the smallest pathological changes in heart rhythm much more accurately.

P wave

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

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

• Positivity and negativity. 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 seconds. Elongation indicates, the tooth is called P mitrale, and is typical of.

PQ interval

The PQ interval corresponds to atrial systole and air retention in the AV node. Measured from the beginning of the P wave to the beginning of the ventricular complex. Normal values ​​are from 0.12 to 0.20 seconds.

Pathology:

• prolonged PQ interval occurs in AV node blocks;
• a shortened PQ interval indicates preexcitation syndrome (air bypassing the AV node through parallel connections).

If the P wave does not contain a cardiac cardiogram, the PQ interval is not deciphered (the same applies to the case if the P wave does not depend on the QRS complex).

QRS complex

The QRS complex represents the contraction of the ventricular cardiac muscle:

• Q – first negative oscillation, may be absent;
• R – each positive oscillation. Usually only one is present. If there is more than 1 vibration of R in a complex, it is indicated by an asterisk (for example, R*);
• S – every negative oscillation after at least one R. A larger number of oscillations is designated similarly to R.

The QRS complex evaluates 3 factors:

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

If after overall assessment The ECG reveals LBBB, Sokolov indices are not measured.

QRS indicators:

• QRS duration. The physiological duration of the QRS complex is up to 0.11 s. Pathological extension up to 0.12 s. may indicate incomplete block, myocardial infarction and ventricular hypertrophy. Extension over 0.13 s. indicates LBBB.
• Q fluctuations. Q oscillations are detected in all terminals. 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 longer than 0.04 s. clearly shows the scar after. Based on the data of their individual vibrations, 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 QRS oscillations, the thickness of the chamber wall can be approximately determined. For this purpose, Sokolov indices are used, 1 for the right and 2 for the left ventricle.

Indicators for the right ventricle:

• the sum of the P wave amplitudes in leads V1, S and lead V6 usually does not exceed 1.05 mV;
• normal readings: 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 vibration in tap V1 and in the R vibration in taps V5 or V6.

• 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:

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

T wave

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

• I and II – positive concordant;
• III – concordant (polarity does not matter);
• aVR – negative T wave on 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 when.

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 ECG assessment.

Research results

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

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