What does a heart cardiogram mean? Cardiogram of the heart (ECG) interpretation. ECG methods

The concept "ECG" stands for "electrocardiogram". This is a graphical recording of the electrical impulses of the heart.

The human heart has its own pacemaker. The pacemaker is located directly in the right atrium. This place is usually called the sinus node. The impulse that comes from this node is called the sinus impulse (it will help decipher what the ECG will show). It is this source of impulses that is located in the very heart and produces electrical impulses itself. They are then sent to the conduction system. Impulses in people who do not have cardiac pathology pass through the cardiac conduction system evenly. All these outgoing impulses are recorded and displayed on the ECG tape.

It follows from this that an ECG - electrocardiogram - is a graphically recorded impulse of the cardiac system. Will an ECG show heart problems? ? Of course it's great and quick way detect any heart disease. Moreover, an electrocardiogram is the most basic method in diagnosing pathology and various heart diseases.

It was created by the Englishman A. Waller back in the seventies of the 19th century. Over the next 150 years, the machine that records the electrical activity of the heart has undergone changes and improvements. Although the principle of operation has not changed.

Modern ambulance teams are necessarily equipped with portable ECG devices, with which you can quickly make an ECG, saving valuable time. Using an ECG, you can even diagnose a person. An ECG will show heart problems: from acute cardiac pathologies to In these cases, not a minute can be lost, and therefore a timely cardiogram can save a person’s life.

The doctors of the ambulance teams themselves decipher the ECG tape and in the case of acute pathology, if the device shows a heart attack, then, turning on the siren, they quickly take the patient to the clinic, where he will immediately receive emergency care. But in case of problems, urgent hospitalization is not necessary; everything will depend on what the ECG shows.

In what cases is an electrocardiogram prescribed?

If a person has the symptoms described below, the cardiologist will refer him to an electrocardiogram:

• legs swell;
• fainting conditions;
• there is shortness of breath;
• chest pain, back pain, neck pain.

An ECG is mandatory for pregnant women for examination, for people preparing for surgery, or for a medical examination.

ECG results are also required if you travel to a sanatorium or if you need permission for any sports activities.

For prevention and if a person has no complaints, doctors recommend taking an electrocardiogram once a year. Often this can help diagnose cardiac pathologies that are asymptomatic.

What will the ECG show?

On the tape itself, the cardiogram can show a combination of waves, as well as recessions. These teeth are designated in capital Latin letters P, Q, R, S and T. When deciphering, the cardiologist studies and deciphers the width, height of the teeth, their size and the intervals between them. Based on these indicators, you can determine the general condition of the heart muscle.

Using an electrocardiogram, various heart pathologies can be detected. Will an ECG show a heart attack? Absolutely yes.

What does an electrocardiogram determine?

• Heart rate - heart rate.
• Rhythms of heart contractions.
• Heart attack.
• Arrhythmias.
• Ventricular hypertrophy.
• Ischemic and cardystrophic changes.

The most disappointing and serious diagnosis on the electrocardiogram is myocardial infarction. In the diagnosis of heart attacks, the ECG plays an important and even the main role. Using a cardiogram, the zone of necrosis, the localization and depth of lesions in the heart area are revealed. Also, when decoding the cardiogram tape, you can recognize and distinguish acute myocardial infarction from an aneurysm and past scars. Therefore, when undergoing a medical examination, it is necessary to do a cardiogram, because it is very important for the doctor to know what the ECG will show.

Most often, a heart attack is associated directly with the heart. But it is not so. A heart attack can occur in any organ. Occurs (when lung tissue partially or completely dies if arteries are blocked).

There is a cerebral infarction (otherwise known as ischemic stroke) - the death of brain tissue, which can be caused by thrombosis or rupture of brain vessels. With a cerebral infarction, functions such as speech, physical movement, and sensation may be completely lost or lost.

When a person has a heart attack, living tissue in their body dies or becomes necrosis. The body loses tissue or a section of an organ, as well as the functions performed by this organ.

Myocardial infarction is the death or ischemic necrosis of areas or areas of the heart muscle itself due to complete or partial loss of blood supply. Heart muscle cells begin to die approximately 20-30 minutes after blood flow stops. If a person has a myocardial infarction, blood circulation is disrupted. One or more blood vessels fail. Most often, heart attacks occur due to blockage of blood vessels by blood clots (atherosclerotic plaques). The area of ​​distribution of the infarction depends on the severity of the dysfunction of the organ, for example, extensive myocardial infarction or microinfarction. Therefore, you should not immediately despair if the ECG shows a heart attack.

This becomes a threat to the functioning of the entire cardiovascular system of the body and threatens life. In modern times, heart attacks are main reason mortality among the population of developed countries of the world.

Symptoms of a heart attack

• Dizziness.
• Labored breathing.
• Pain in the neck, shoulder, which can radiate to the back, numbness.
• Cold sweat.
• Nausea, feeling of a full stomach.
• Feeling of tightness in the chest.
• Heartburn.
• Cough.
• Chronic fatigue.
• Loss of appetite.

The main signs of myocardial infarction

1. Intense pain in the heart area.
2. Pain that does not go away after taking nitroglycerin.
3. If the pain lasts for more than 15 minutes.

Causes of heart attack

1. Atherosclerosis.
2. Rheumatism.
3. Congenital heart defect.
4. Diabetes.
5. Smoking, obesity.
6. Arterial hypertension.
7. Vasculitis.
8. Increased blood viscosity (thrombosis).
9. Previous heart attacks.
10. Severe coronary artery spasms (for example, when taking cocaine).
11. Age-related changes.

An ECG can also identify other diseases, such as tachycardia, arrhythmia, and ischemic disorders.

Arrhythmia

What to do if the ECG shows arrhythmia?

Arrhythmia can be characterized by numerous changes in the contraction of the heartbeat.

Arrhythmia is a condition in which there is a disturbance in the heart rhythm and heart rate. More often, this pathology is marked by an irregular heartbeat; The patient has either a rapid or slow heartbeat. An increase is observed when inhaling, and a decrease is observed when exhaling.

Angina pectoris

If the patient experiences attacks of pain under the sternum or to the left of it in the area of ​​the left arm, which can last a few seconds or can last up to 20 minutes, then the ECG will show angina.

The pain usually intensifies with lifting weights, heavy physical activity, or going out into the cold and may disappear with rest. Such pain decreases within 3-5 minutes when taking nitroglycerin. The patient's skin turns pale and the pulse becomes uneven, which causes interruptions in the functioning of the heart.

Angina pectoris is one of the forms of the heart. It is often quite difficult to diagnose angina pectoris, because such abnormalities can also manifest themselves in other cardiac pathologies. Angina pectoris can further lead to heart attacks and strokes.

Tachycardia

Many people are very worried when they find out that the ECG showed tachycardia.

Tachycardia - increase at rest. Heart rhythms during tachycardia can reach 100-150 beats per minute. This pathology can also occur in people, regardless of age, when lifting heavy objects or during increased physical activity, as well as during strong psycho-emotional arousal.

Still, tachycardia is considered not a disease, but a symptom. But it is no less dangerous. If the heart begins to beat too quickly, then it cannot have time to fill with blood, which subsequently leads to a decrease in blood output and a lack of oxygen in the body, as well as the heart muscle itself. If tachycardia lasts more than a month, it can lead to further disruption of the heart muscle and an increase in heart size.

Symptoms characteristic of tachycardia

• Dizziness, fainting.
• Weakness.
• Dyspnea.
• Increased anxiety.
• Feeling of increased heart rate.
• Heart failure.
• Pain in the chest area.

The causes of tachycardia can be: coronary heart disease, various infections, toxic effects, ischemic changes.

Conclusion

Nowadays, there are many different heart diseases that can be accompanied by excruciating and painful symptoms. Before starting their treatment, it is necessary to diagnose, find out the cause of the problem and, if possible, eliminate it.

Today, an electrocardiogram is the only effective method in diagnosing heart pathologies, which is also completely harmless and painless. This method is suitable for everyone - both children and adults, and is also accessible, effective and highly informative, which is very important in modern life.

Introduction.

After the previous review, I received a lot of comments about the first newsletter.

Users focused on the difficulty of understanding the material and the lack of clarity, this newsletter will try to correct everything.

1. What is an ECG (electrocardiogram)?

The word "electrocardiogram" with Latin language literally translated as follows:

ELECTRO—electric potentials;

CARDIO - heart;

GRAM - recording.

Therefore, an electrocardiogram is a recording of the electrical potentials (electrical impulses) of the heart.

2. Where is the source of impulses in the heart?

The heart works in our body under the guidance of its own pacemaker, which produces electrical impulses and directs them to the conduction system.

Rice. 1. Sinus node

The pacemaker of the heart is located in the right atrium at the confluence of the vena cava, i.e. in the sinus, and is therefore called the sinus node, and the excitation impulse emanating from the sinus node is called the sinus impulse.

In a healthy person, the sinus node produces electrical impulses with a frequency of 60-90 per minute, uniformly sending them through the conduction system of the heart. Following it, these impulses excite the parts of the myocardium adjacent to the conduction pathways and are recorded graphically on the tape as an ECG curve line.

Consequently, an electrocardiogram is a graphical display (registration) of the passage of an electrical impulse through the conduction system of the heart.

Rice. 2. Tape E K G. teeth and intervals

The passage of an impulse through the conduction system of the heart is graphically recorded vertically in the form of peaks - rises and falls of a curved line. These peaks are usually called electrocardiogram waves and are designated by the Latin letters P, Q, R, S and T.

In addition to recording the waves, the time during which the impulse travels through certain parts of the heart is recorded horizontally on the electrocardiogram. A segment on an electrocardiogram measured by its duration in time (in seconds) is called an interval.

3. What is a P wave?
Rice. 3. P wave - atrial excitation.

The electrical potential, having gone beyond the sinus node, excites primarily the right atrium, in which the sinus node is located. This is how the peak excitation of the right atrium is recorded on the ECG.

Rice. 4. Excitation of the left atrium and its graphic representation

Next, through the conduction system of the atria, namely the interatrial bundle of Bachmann, the electrical impulse passes to the left atrium and excites it. This process is reflected on the ECG by a peak of excitation of the left atrium. Its excitation begins at a time when the right atrium is already engulfed in excitement, which is clearly visible in the figure.

Rice. 5 P wave.

Displaying the excitations of both atria, the electrocardiographic apparatus sums up both peaks of excitation and records the P wave graphically on the tape.

Thus, the P wave is a summation display of the passage of the sinus impulse through the conduction system of the atria and the alternate excitation of first the right (ascending limb of the P wave) and then the left (descending limb of the P wave) atria.

4. What is the P-Q interval?

Simultaneously with the excitation of the atria, the impulse leaving the sinus node is sent along the lower branch of the Bachmann bundle to the atrioventricular (atrioventricular) junction. A physiological delay of the impulse occurs in it (slowing down the speed of its conduction). Passing through the atrioventricular junction, the electrical impulse does not cause excitation of the adjacent layers, therefore excitation peaks are not recorded on the electrocardiogram. The recording electrode draws a straight line called an isoelectric line.

The passage of an impulse through the atrioventricular connection can be assessed in time (how many seconds does it take for the impulse to travel through this connection). This is the genesis of the P-Q interval.

Rice. 6. P-Q interval 5. What are the “Q”, “R”, “S” waves?

Continuing its path through the conduction system of the heart, the electrical impulse reaches the conduction pathways of the ventricles, represented by the His bundle, passes through this bundle, thereby stimulating the ventricular myocardium.

Rice. 7. Excitation of the interventricular septum (Q wave)

This process is reflected on the electrocardiogram by the formation (recording) of the ventricular QRS complex.

It should be noted that the ventricles of the heart are excited in a certain sequence.

First, the interventricular septum is excited for 0.03 s. The process of its excitation leads to the formation of a Q wave on the ECG curve.

Then the apex of the heart and adjacent areas are excited. This is how the R wave appears on the ECG. The apex excitation time is on average 0.05 s.

Rice. 8. Excitation of the apex of the heart (R wave)

And last of all, the base of the heart is excited. The consequence of this process is the registration of the S wave on the ECG. The duration of excitation of the base of the heart is about 0.02 s.

Rice. 9. Excitation of the base of the heart (S wave)

The above-mentioned Q, R and S waves form a single ventricular QRS complex with a duration of 0.10 s.

6. What are S-T segments and T waves?

Having embraced the ventricles with excitement, the impulse that began its journey from the sinus node fades away, because the myocardial cells cannot remain excited for long. They begin the processes of restoring their original state before the excitement.

The processes of extinction of excitation and restoration of the initial state of myocardiocytes are also recorded on the ECG.

The electrophysiological essence of these processes is very complex, here great importance there is a rapid entry of chlorine ions into the excited cell, coordinated operation of the potassium-sodium pump, there is a phase of rapid decay of excitation and a phase of slow decay of excitation, etc. All complex mechanisms of this process are usually united by one concept - repolarization processes. For us, the most important thing is that the repolarization processes are displayed graphically on the ECG by the S-T segment and the T wave.

Rice. 1 0. Processes of excitation and repolarization of the myocardium 7. We figured out the teeth and intervals, but what is their normal size?

To remember the size (height or depth) of the main waves, you need to know: all devices that record ECG are configured in such a way that the control curve drawn at the beginning of the recording is equal in height to 10 mm, or 1 millivolt (m V).

Rice. 1 1. Control curve and height of the main ECG waves

Traditionally, all measurements of waves and intervals are usually made in the second standard lead, designated by the Roman numeral II. In this lead, the height of the R wave should normally be 10 mm, or 1 mV.

Rice. 1 2. Time on ECG tape

The height of the T wave and the depth of the S wave should correspond to 1/2-1/3 of the height of the R wave or 0.5-0.3 mV.

The height of the P wave and the depth of the Q wave will be equal to 1/3-1/4 of the height of the R wave or 0.3-0.2 mV.

In electrocardiography, the width of the waves (horizontally) is usually measured not in millimeters, but in seconds, for example, the width of the P wave is 0.10 s. This feature is possible because the ECG is recorded at a constant tape feed speed. So, with a tape drive speed of 50 mm/s, each millimeter will be equal to 0.02 s.

For convenience, characterizing the duration of the teeth and intervals, remember the time equal to 0.10 +- 0.02 s. In further study of the ECG, we will often refer to this time.

The width of the P wave (how long it takes for the sinus impulse to cover both atria with excitation) is normal. 0.10±0.02s.

The duration of the P-Q interval (how long it takes for the sinus impulse to travel through the atrioventricular junction) is normal. 0.10 ± 02 s.

The width of the ventricular QRS complex (how long it takes for the sinus impulse to cover the ventricles with excitation) is normally: 0.10 ± 0.02 s.

The sinus impulse to excite the atria and ventricles will normally require (taking into account that normally it can only reach the ventricles through the atrioventricular connection) 0.30 ± 0.02 s (0.10 - three times).

Indeed, this is the duration of excitation of all parts of the heart from one sinus impulse. It has been empirically determined that the repolarization time and the excitation time of all parts of the heart are approximately equal.

Therefore, the duration of the repolarization phase is approximately 0.30 ± 0.02 s.

Let’s summarize the results of the first revised version of the “ECG. sources of waves, intervals and segments on the ECG. ECG is normal (physiological).”:

1. An excitation impulse is formed in the sinus node.

2. Moving along the conduction system of the atria, the sinus impulse alternately excites them. Alternate excitation of the atria is graphically displayed on the ECG by recording the P wave.

3. Following along the atrioventricular connection, the sinus impulse undergoes a physiological delay in its conduction and does not excite the adjacent layers. A straight line is recorded on the ECG, which is called an isoelectric line (isoline). The segment of this line between the P and Q waves is called the P - Q interval.

4. Passing through the conduction system of the ventricles (bundle of His, right and left bundle branches, Purkinje fibers), the sinus impulse excites the interventricular septum and both ventricles. The process of their excitation is reflected on the ECG by recording the ventricular QRS complex.

5. Following the processes of excitation in the myocardium, repolarization processes begin (restoration of the original state of myocardiocytes). Graphic display of repolarization processes leads to the formation of S-T interval and T wave.

6. The height of the teeth on the electrocardiographic tape is measured vertically and expressed in millivolts.

7. The width of the teeth and the duration of the intervals are measured horizontally on the tape and expressed in seconds.

Additional information for the first newsletter:

1. Segment information

In electrocardiography, a segment is considered to be a segment of the ECG curve in relation to the isoelectric line. For example, the S-T segment is located above the isoelectric line or the S-T segment is located below the isoline.
Rice. 13. Segment S-T above and below the isoline

2. The concept of internal deviation time

The conduction system of the heart, which was discussed above, is located under the endocardium, and in order to cover the heart muscle with excitement, the impulse seems to “penetrate” the thickness of the entire myocardium in the direction from the endocardium to the epicardium

Rice. 1 4. The path of the impulse from the endocardium to the epicardium

It takes a certain time for the excitation to cover the entire thickness of the myocardium. And this time during which the impulse travels from the endocardium to the epicardium is called the internal deflection time and is denoted by the capital letter J.

Determining the time of internal deviation on an ECG is quite simple: to do this, you need to lower the perpendicular from the top of the K wave until it intersects with the isoelectric line. The segment from the beginning of the Q wave to the point of intersection of this perpendicular with the isoelectric line is the time of internal deflection.

The internal deviation time is measured in seconds and is equal to 0.02-0.05 s.

Rice. 1 5. Determination of internal deviation time

Inna Izmailova

This publication is not a textbook on medicine. All treatment procedures must be agreed with the attending physician.

All rights reserved. No part of this book may be reproduced in any form without the written permission of the copyright holders.

The worst thing is when children get sick. We were diagnosed with a “patent foramen ovale” when our daughter was 12 years old. We contacted the Institute of Maternal and Child Health in Kyiv, and they told us that “we need to observe” and nothing more specific. But it was very alarming, so we looked for information. I received the book in a timely manner, very accessible and clearly written. We look into the future with optimism, many thanks to the authors!

Vitaly Kravchenko, Kyiv

A. S. Kharitonov, 47 years old

The book you are holding in your hands was co-authored by a doctor and a patient.

The patient, however, was not me, but my son, whose doctor Inna Mikhailovna Izmailova discovered heart problems during an appointment. We came with a good ECG and normal tests, to put on the card admission to classes after lobar pneumonia. Inna Mikhailovna, barely glancing at the ECG tape, began a physical examination. And after listening for a long time, she said: “I don’t believe your cardiogram - I need to repeat it. Let's do it now!" We have known Dr. Izmailova for a long time and warmly as neighbors. And in the office that day we met for the first time: a taciturn specialist who did not allow objections.

On the second attempt, the ECG recorded an arrhythmia, which the doctor detected with his ear. Then there was an additional examination. It showed that the infection was not limited to the lungs, but also bit heart valve. When it turns out that a child has heart problems, parents are very scared. The son, a strong young man who was confident in his health, was also quite depressed. And a long treatment of the heart began - an organ about which I knew almost nothing at that time. And our doctor, by the way, was not aimed at explanations: “Believe me, this is serious. But we caught it in time - we’ll get treatment and everything will go away. Carry out your assignment, don’t be burdened with unnecessary knowledge!”

I just wanted to understand as much as possible what was happening. The terms “extrasystole” and “valve regurgitation” were frightening. The examination seemed incomprehensible, the prescription strange. I had to read, understand, write down, and take the “sapient patient” course. And then explain what he had learned to his son, because due to ignorance he “failed” tests and was worried. The heart was initially beating too fast from excitement, and research under additional stress became unacceptable. When we wised up, the rhythm returned to normal: knowledgeable person not only calm during the exam, but also in the diagnostic room.

To my surprise, after some time I managed to “qualifiedly” calm down my sick colleague. Unpleasant symptoms in the heart area seemed to her a harbinger of something terrible, because her parents (both!) died early due to heart disease. I persuaded my colleague to put aside her fear and go with me to the doctor, joked: “The doctor will treat you, and I’ll tell you what and why!”

Once I gently reproached Inna Mikhailovna that indifferent and uneducated patients are a thing of the past. And that treating us is not enough, we need to heal more! And she answered bitterly that the time allotted for seeing the patient was catastrophically insufficient. “So, doctor,” I asked, “we need to write books for patients, and not just for colleagues and students!”

From this conversation, I got the idea to create notes about arrhythmia: what you need to know about your heart so that, on the one hand, you do not develop a hypochondriac in yourself and, on the other hand, you do not show carelessness. Every person experiences arrhythmia, and in every person it can go beyond the normal limits after a banal infection or stress. The chest protects the heart from shocks, and we ourselves must protect it from everything else - with a reasonable attitude. I was fascinated by working on the notes, and when they were finished, I showed them to Dr. Izmailova. To my pleasant surprise, she took on the task of clarifying, correcting and, in the end, calling them worthy popular science material. These same notes have now been expanded into a real book. And this is the merit not of the patient, but of the doctor, who systematized heart diseases and explained to the reader the most important thing - any possible pathology! Treatment, that is, a conversation for which time is not allocated at an appointment with a therapist, cardiologist, or arrhythmologist, took place on these pages. This conversation is important for everyone because everyone has a heart.

There is such a concept in medical statistics as cardiovascular risk . associated not so much with the heart, but with the gender-social factor. In our country this risk is very high. And the most achievable way to reduce it is through our awareness and understanding of our hearts. Speaking strictly and seriously, no matter how high the level of medical care, we ourselves are able to serve our heart much better, we just have to get to know it!

Work on mistakes

The outstanding American cardiologist Paul Dudley White, who during the Khrushchev Thaw became a foreign member of the USSR Academy of Medical Sciences, made a lot of efforts in the field of preventive cardiology. Among his main works is a monograph on the characteristics of cardiovascular diseases in young people, on the possibility and methods of extending life into old age. Dr. White has a statement that back in the 60s could have become the motto of every health department, if it had not exposed White as a man of faith: Heart disease before age 80 – not God’s punishment, but a consequence of one’s own mistakes!

If you thought that below would be a familiar and boring list of bad habits that you need to get rid of, criticism of fast food, frequent night vigils and calls to immediately do exercises - you are, in general, close to the truth. You are a man of iron logic, and today you are clearly (or mentally) walking on the right path - shouldn’t I urge you on? for what!

But on the right road there are hidden irregularities, bumps, insidious traps, the existence of which cannot be predicted, because our own body masks them, turning off the instinct of self-preservation. And nothing can be done about it: the body gains experience no earlier than we ourselves gain experience. And he is more resilient than ours! Through incredible efforts of will, we sometimes overcome the “dead point” during physical activity, experience shortness of breath, tightness in the chest, and feel the pulsation of blood vessels in the head. We run with all our strength, it seems that we are about to fall, we want to leave the race - and the body suddenly gets a “second wind”! It allows you to run and creates the illusion of endless reserve possibilities.

From time to time, reports appear in the media about the awkward deaths of unjustifiably self-confident young people: one enthusiast worked for several days without rest, another won a beer festival at the cost of his own life, the third was a passionate sports fan and sacrificed a night’s sleep for a week for the sake of passion. Some famous artists, due to the busy schedule of performances and filming, give themselves a heart attack at the age of 30. And even strong people, champions of sports and favorites of the public, sometimes fall as if knocked down right in the sports arena - the heart exhausts its capabilities.

Among middle-aged people, a sudden illness leading to disability or death is in most cases associated with problems of the cardiovascular system. And this despite the fact that 90?% of cases of sudden death of able-bodied, intelligent, energetic people can be prevented! Their body, most likely, was designed by nature to last 100 years. But an error has crept into human calculations of daily physical activity. A serious mistake, leading first to great fatigue, constant drowsiness, then to palpitations, barely noticeable drops in pulse, and finally to a fatal heart attack.

In conditions that “can be neglected,” we stimulate ourselves with coffee or fashionable tinctures of ginseng and ginger “for a surge of strength.” In fact, it is to aggravate the disruption of the heart rhythm. Every minute someone on earth becomes a victim of similar errors, which cardiologists selflessly try to correct. Because they know for sure: it was not God’s punishment that fell upon a person, but the result of a misunderstanding, a lack of understanding of one’s own heart - and one must fight for life.

Here's an interesting fact for you! Most organs in the body use only a quarter of the oxygen supplied by the blood for nutrition. The heart consumes three quarters of oxygen from the blood of the coronary arteries. It depends three times more than other organs and systems on adequate gas exchange and nutrition. Now think about the fact that a tired or sick body cannot nourish our heart to the required extent, nor carry out its normal nervous and hormonal regulation not able to.

But the heart is able to give soft signals for quite a long time about the disease of the associated organs, about brain fatigue, while working at the required volume. You need to catch these signals in time and learn to respond to them adequately: carefully, quickly and without unnecessary panic. You need to respond even faster to heart signals about your own pathology, since these are urgent conditions. To do this, you don’t need much at all – to know your heart!

It is never too early to become familiar with the work of the most tireless organ of our body, understand it and become its friend. While the heart is still resilient, it is not too late to overcome the consequences of our past mistakes. While we are alive, no matter what we are sick with, there is still time to help a tired heart get healthier and prolong our life. We will find out how to do this on the pages of this book!

Chapter 1. Every person experiences arrhythmia

Command your heart to “knock evenly!” as hopeless as forbidding yourself to love, worry, rejoice, run, jump and actually live - interestingly and fully. The heart always works in accordance with the physical and mental state person. This condition is very variable, so throughout our lives we experience arrhythmia from time to time.

Certain types of arrhythmia can be classified as “cosmetic”; they do not need to be treated if they do not cause us inconvenience. Let's figure out which heart rate is within the normal range and which indicates problematic situations in the body.

Sinus rhythm is normal

If you have ever had an electrocardiogram, then you could read in its transcript sinus rhythm . This is the most correct rhythm, and here's why. There is a special node in the heart, called the “sinus” node, which gives an electrical impulse to cardiac activity. Passing along the nerve fibers, the electrical impulse causes the heart muscle to contract. In Fig. 1 you can see where this node is located: at the point where the vena cava flows into the right atrium. The idea of ​​a node will just satisfy the curiosity of most of us: rarely does the pacemaker become displaced from the sinus node. Although, unfortunately, this happens and requires a solution to the problem. We will talk about this periodically.

Rice. 1. Pacemakers

In sinus rhythm, the normal heart rate (HR) for an adult is 60–90 beats per minute, and even 100 beats is not too bad. For children, the norm is much higher - up to 140 beats.

Let's count heart rate correctly!

The correct measurement is to count the beats for 2 minutes. The result obtained must be divided by two, this will be the average heart rate for 1 minute.

So, measured heartbeats that do not exceed the established limits indicate that the body is at rest, the “electrical wiring” of the heart is not disturbed, the heart works as usual. If the heart rate exceeds 100 beats per minute, the heart is in a hurry, but at the same time beats rhythmically - we have tachycardia. But this is a normal situation; physiologically, tachycardia can manifest itself daily!

The “flame motor” obeys the law of automatism

From the point of view of a person far from medicine, the heart performs one function - it is a continuous blood pump. Those who seriously study the capabilities of the heart say that it is endowed with the functions of automaticity, excitability, conductivity, contractility and some others. All functions are interconnected, and it is impossible to single out the main one. Automatism - this is the ability of our heart, without any external influences, to contract rhythmically and consistently, second by second, day by day, decade by decade. And the reason for automatism still remains a mystery!

IN myocardium (as the heart muscle is called), there are three centers of automatic excitation (Fig. 1):

The sinus node, located in the wall of the right atrium, which generates impulses at a frequency of 60–90 units per minute. This first order pacemaker .

The atrioventricular node at the base of the right atrium and in the interatrial septum has a self-excitation rate of 40–60 times per minute. This second order pacemaker .

Ventricular centers of automaticity ( third order pacemaker ) operate at a frequency of 30 times per minute.

The law of automatism that the heart obeys is that the pacemaker with the highest frequency of self-excitation determines the rhythm of the heart. And this is the sinus node! If the rhythm is disrupted, but the pacemaker remains in the sinus node, they speak of sinus tachycardia . increased heart rate, which is familiar to any person. Or about sinus bradycardia (slow pulse), it is inherent in the heart of athletes. Cases of displacement of the pacemaker from the sinus node can be detected accidentally on the electrocardiogram. But they require attention because they are a consequence of damage to the pacemaker of the first or second order.

Any abnormal heart rhythm is called arrhythmia . There is even a branch of cardiology called “arrhythmology”. We will mainly focus on those problems that the patient encounters for the first time - in order, on the one hand, to prevent unnecessary worries. And on the other hand, to prevent carelessness in relation to a serious arrhythmia that does not give subjective sensations.

The myocardium, the heart muscle, unlike other muscles of the body, relaxes only for a split second. During a human life, it carries out 2.5 billion cycles of contraction and relaxation.

Heart rate and blood fraction volume are regulated by two mechanisms. The main one is the central nervous system. It works automatically and causes the heart to contract at the required rhythm, even when we sleep. One group of the nervous network accelerates the heart rate, while the other slows it down.

The second mechanism of regulation is through hormones. Adrenaline, a hormone produced by the adrenal glands, causes the heart to beat faster. This increases the body’s readiness for action. Hyperactivity thyroid gland causes a constant increase in heart rate and tires the heart. And reduced thyroid function unjustifiably slows down the pulse, as a result a person freezes even in a warm room.

When does tachycardia require treatment?

Whatever the nature of tachycardia (physiological or pathological, that is, painful), it is only a symptom. Physiological tachycardia is a normal response of the heart to physical activity, a normal reaction to the release of hormones of joy or stress into the blood. 10 minutes after physical activity, the heart rate should return to its normal rhythm, if the load was not prohibitive. Sports training that overloads the heart must be reduced, otherwise it will not bring any benefit to the body.

To determine your maximum heart rate (HR), subtract your age in years from 220. If you are 40 years old, your maximum heart rate should not exceed 180 beats per minute.

Tachycardia during exercise should gradually increase and go away smoothly. Remember that to normalize heart rate, a healthy person performing a feasible exercise needs no more than 5 minutes! Exceeding this time indicates an unbearable load or problems in the body.

Tachycardia is necessarily accompanied by an increase in body temperature: with an increase in body temperature by 1 degree, heart rate increases by 8–10 beats per minute. The temperature normalizes, and the tachycardia goes away.

Pathological tachycardia occurs without visible reasons and significantly worsens the quality of life. If it suddenly begins to cause palpitations that do not stop within 15 minutes, you should consult a therapist. Tachycardia is especially unpleasant, which manifests itself as obsessive frequent beats at rest, unexpectedly, and is accompanied by sweating, dizziness, chest pain, a feeling of fear, and sometimes fainting. Such symptoms require identification of a cause, and the list of suspected causes is extensive.

Thyroid diseases.

Anemia, low blood hemoglobin.

Constant intake of stimulants medicines(atropine, caffeine, aminophylline).

Poisoning of any nature.

Respiratory failure, acute or chronic.

Increased blood pressure.

Congenital defects hearts; atherosclerosis of blood vessels, leading to malnutrition of the myocardium (heart muscle).

Myocardial inflammation.

Coronary heart disease, including acute conditions: heart failure, angina pectoris, myocardial infarction.

If the causes of tachycardia are not related to the functioning of the heart and blood vessels, it will go away after treatment of the underlying disease. In other cases, a cardiologist will begin to work with tachycardia, since the arrhythmia is a response to a decrease contractility of the heart . That is, the heart performs its work in the body to the required extent, but only due to frequent contractions, and not due to the force of the push. And through subjective sensations it demands help from us.

IN in some cases in case of tachycardia an ambulance is required or urgent Care. The heart rate is sometimes such that it becomes impossible to count the beats. The pacemaker is displaced from the sinus node, and only an emergency physician, based on the results of an electrocardiogram, can determine what type of tachycardia is: atrial, ventricular. An attack of tachycardia in such cases is manifested by paroxysms (frequent peak repetitions), it should be eliminated immediately. And in the future, treat the heart or blood vessels.

Attacks of rapid heartbeat, which are accompanied by dizziness, darkening of the eyes, pain in the heart, weakness, nausea - this is paroxysmal tachycardia. You need to call an ambulance!

Stop heart attack. How to read an ECG and take care of your heart

We regret to admit that the causes of cardiac conduction and rhythm disturbances often remain unknown. Firstly, because there are usually several reasons for this. Secondly, because the functions of the heart are still not sufficiently studied, there are too many factors influencing its work. But risk groups are identified statistically and do not raise doubts. There is also no doubt that a healthy lifestyle plays an important role in maintaining normal heart conduction.

Typical complaints with conduction disorders

On initial stages complaints with conduction disturbances do not differ from complaints with disturbances in the automaticity or excitability of the heart. Therefore, any condition requires a thorough examination. Most often the nature of the complaints is as follows.

Palpitations (strong and rapid heart beats). Such complaints are characteristic of tachycardia.

Periodic “loss” of the next contraction, which can be detected both subjectively and objectively if you measure heart rate for 2 minutes.

Palpitations may be accompanied by dizziness or fainting, as a result of hypoxia, that is, insufficient oxygen supply to the brain with blood.

Pain in the heart area, often of the angina type: burning behind the sternum, shortness of breath with normal exertion. Read about what angina is and what its manifestations are in Chapter 4. Angina pectoris and atherosclerosis of coronary vessels .

Arrhythmias due to cardiac conduction disturbances

At the beginning of this section, we already became familiar with the concepts of sinus tachycardia and sinus bradycardia. These rhythm disturbances occur in the sinus node, that is, they are associated with a violation of automaticity, but are not associated with disturbances in conductivity and excitability. Tachycardias associated with suppression of sinus node function are atrial and ventricular tachycardia. Read about them in the section Let us only add that in case of conduction disturbances, not only short-term paroxysmal tachycardias are characteristic (as in the case of excitability disturbances), but also permanent non-sinus tachycardias that last more than six months.

Now we will talk about the most threatening arrhythmias caused by impaired conduction of the heart: flickering and fluttering of the heart.

Atrial fibrillation

In Latin, atrial fibrillation is eloquently called: “madness of the heart.” Ancient doctors called it that, not yet knowing that with this pathology, the effective sinus rhythm is disrupted and the heart cannot pump out blood in a sufficient volume. The atria work not only not synchronously, but completely randomly, they flutter and “flicker”. Following the atria, the ventricles begin to contract irregularly and rapidly.

Risk group

Atrial fibrillation (flickering, or atrial fibrillation ), unfortunately, is familiar to many regular patients of cardiologists firsthand.

In 40–50 year old people, atrial fibrillation does not occur often; after 60 years, the danger increases many times. And in old age, every tenth person experienced an attack of atrial fibrillation, which is associated with a constant worsening of the pathology of blood vessels and the heart. Hypertension is often the basis for atrial fibrillation because high blood pressure leads to stretching of the chambers of the heart and atria.

An overactive thyroid gland (thyrotoxicosis) and alcohol abuse can lead to atrial flutter at a young age. Hereditary factor also plays an important role.

For the development of arrhythmia, the trigger mechanism is often an electrolyte imbalance.

If during the flu or acute respiratory viral infection the patient sweats a lot, but does not replenish fluid loss by drinking, the body quickly loses potassium. Such an imbalance, in principle, increases the risk of arrhythmias, including the risk of atrial fibrillation!

Symptoms of atrial fibrillation

Subjective sensations with atrial fibrillation vary greatly. Elderly patients may not feel discomfort. Atrial flutter is detected randomly by ECG.

In other patients, the heart rate reaches 200 beats, weakness and even fainting appear. Sometimes, for several days, a person ignores causeless fatigue, shortness of breath, and feelings of anxiety and seeks help only if he feels a dull pain in the chest or a sharp decrease in blood pressure.

If atrial fibrillation occurs in attacks, it is called paroxysmal atrial fibrillation .

Consequences and complications

With atrial fibrillation, the chambers of the heart contract asynchronously, and blood can stagnate in them. This creates conditions for the formation of clots, which can be released into the blood when the heart contracts. The consequences depend on whether the complication can be diagnosed in time and the blood clot dissolved. Otherwise, it will turn into a blood clot that blocks a vessel.

Drinking significant amounts of alcohol greatly increases the risk of atrial fibrillation.

There is sad statistics of an increase in hospitalization of young and middle-aged men with attacks of atrial fibrillation after the New Year holidays. A sleepless night and excessive alcohol consumption disables the sinus node and creates conditions for cardiac conduction disturbances.

In most cases, doctors are able to relieve the attack because the blood vessels of young men are not worn out. However, there is reason to think about healthy way life!

In older people whose blood vessels are damaged atherosclerosis (read about atherosclerosis in Chapter 4 Angina and atherosclerosis of the coronary vessels), there is a high risk of blockage of blood vessels in the brain. Therefore, for atrial fibrillation, anticoagulants (blood thinners) are prescribed along with antiarrhythmic drugs.

Atrial flutter

Atrial flutter is a rhythm disturbance that is almost always associated with existing pathologies of the heart muscle: rheumatic disease, myocarditis, mitral heart defects, chronic ischemic heart disease (read about all these pathologies in the following chapters of the book), fibrous changes in the area of ​​the sinus node (the is at the point where the vena cava enters the right atrium).

Flutter is manifested by regular (rhythmic) contractions of the atria with a frequency of up to 350 per minute. In Fig. 10 shows a recording of atrial flutter.

Rice. 10. Recording an ECG for atrial flutter

Prevention of this arrhythmia can only be timely treatment of the underlying heart disease. Moreover, there is almost always time for this. Look at the table and see that, fortunately, this type of arrhythmia cannot be called “young”!

Table 1

Incidence of atrial fibrillation

Ventricular fibrillation (fibrillation)

Such a serious rhythm disorder as fibrillation or ventricular fibrillation of the heart, without urgent cardiac care, leads to death. Ventricular fibrillation is triggered by ventricular tachycardia, which you can read about in the section Excitability.../How to detect extrasystole. 24-hour Holter monitoring. Ventricular fibrillation is always associated with severe cardiac pathology. The severity of the arrhythmia is due to the lack of full contraction of all chambers of the heart, which leads to low blood supply to vital important organs. And also a high risk of cardiac arrest.

And we will not talk more about this arrhythmia only because it is not a primary disorder and cannot occur suddenly. With adequate treatment of heart disease, the doctor will definitely prevent ventricular fibrillation.

Heart blocks

It happens that when recording an ECG during a preventive medical examination, the doctor writes “blockade” in the conclusion. And at the same time, the person did not even suspect that he was sick; there were no subjective sensations. But most often when heart blocks there is a disturbance (slowdown) of the heart rhythm and a feeling of “loss” of pulse beats.

Blockades, that is, disruption of impulse transmission along normal pathways, can occur with any damage to the heart muscle (myocardium). Such lesions include angina pectoris, myocarditis, cardiosclerosis, cardiac hypertrophy . We will not ignore any of these pathologies in subsequent chapters.

In athletes, blockade can occur due to excessive stress on the heart muscle. There is also a hereditary predisposition to blockades. Those patients who are already familiar with this disorder are aware of this classification.

1st degree blockade – impulses are carried out with a significant delay.

Blockade 2nd degree, incomplete – some impulses are not carried out.

Blockade 3rd degree, complete – impulses are not carried out at all. If impulses to the ventricles are not carried out, the heart rate may drop to 30 per minute or lower. When the interval between contractions reaches several seconds, “cardiac syncope” occurs, and convulsions are possible. Without medical assistance, unfortunately, such a blockade will lead to death.

Intraatrial block called a disturbance in the conduction of impulses along the atrial pathways, often leading to asynchronous functioning of the right and left atria. The condition is not as dangerous as ventricular block. Blockades of individual branches of the cardiac conduction system, in principle, do not require special treatment; they only indicate a certain pathology. At successful treatment cardiac pathology, such a symptom as 1st or 2nd degree blockade goes away. Or it is specifically removed with medications.

Diagnosis of blockades

An ECG (electrocardiogram) makes it possible to evaluate the work of the heart only at the time of the study. And blockades can occur periodically - this is the insidiousness of such conditions! To reveal temporary blockades, use 24-hour Holter monitoring. You can read more about it in the section Excitability is another function of the heart/... How to detect extrasystole. 24-hour Holter monitoring.

Sometimes echocardiography is required to clarify the diagnosis. We will dwell on this type of study in detail after explaining the common bundle branch block.

Bundle branch block

If you hear from a cardiologist the complex name “atrioventricular node”, this is the designation of the atrioventricular node in Latin (atrium - atrium, and ventriculus - ventricle). A bundle of conducting fibers coming from the atrioventricular node is called His bundle. named after the famous German anatomist Wilhelm Gies, a foreign member of the St. Petersburg Academy of Sciences.

At the end of the 19th century, Dr. Gies examined the microscopic structure of the heart and described a 20-centimeter bundle of conducting fibers that causes the ventricles of the heart to contract in a timely and synchronous manner.

The bundle of His is divided into right and left legs, going to both halves of the heart (Fig. 11). Disturbances in the passage of an electrical impulse along the length of the His bundle are called bundle branch blocks . Blockades are reflected on the ECG. Sometimes they distort the electrocardiogram so much that they make it difficult to diagnose heart pathology.

Rice. eleven. Conduction system of the heart

Right bundle branch block

If a person feels well, and the electrocardiogram records incomplete blockade of the right bundle branch, this is a variant of the norm. Most likely, a cardiographic effect recorded by chance or caused by excitation of the nervous system. With minor subjective sensations of the patient, it can be assumed that there are so-called electrolyte disturbances. That is, the body lacks the microelements potassium and magnesium. This problem can be easily eliminated - the doctor will prescribe appropriate medications and advise you to eat dried fruits rich in potassium (raisins, apricots, figs).

Complete blockade of the right leg can be caused by congenital or acquired heart defects ( mitral valve stenosis . for example, read about it in Chapter 3. Changes in the mitral valve), coronary heart disease, acute myocardial infarction ( Read about these pathologies in Chapter 4). Complete blockade can occur in people without heart disease, but the cause of the condition will have to be identified, since normal conduction of the system must be restored.

Single bundle branch block (left or right) is not life-threatening. Since the impulse will still cause the ventricles of the heart to contract in a roundabout way.

As an independent manifestation not related to heart pathology, bundle branch block can only be detected on an ECG. And most often it does not require any treatment.

Don't be afraid that during complete blockade right bundle branch, the right half of the heart stops working! Excitement is transmitted to her in a roundabout way: the saving impulse comes from the left half of the heart. The complexity of this situation lies in the fact that the left ventricle contracts first, and then the contraction impulse is slowly transmitted to the right ventricle. Normally, the ventricles should contract simultaneously and quickly, but with incomplete blockade, the slowdown in impulse conduction is subtle or not significant at all.

When the heart rate is high, right bundle branch block sometimes occurs, which is called tachycardia-dependent blockade (that is, dependent on tachycardia). As soon as the tachycardia is removed, the heart block will go away.

Left bundle branch block

Left bundle branch block (complete or incomplete) is always associated with heart damage. It may indicate myocardial infarction, cardiosclerosis, hypertrophy (enlargement) of the left ventricle, acquired heart defects, myocarditis. All these diseases are described in subsequent chapters of the book.

Another reason for the blockade may be a violation of calcium metabolism in the body and calcification (changes in cellular structure) conduction system of the heart.

Unfortunately, if both bundle branches are completely blocked, the condition is equivalent to a 3rd degree block. The only way to eliminate the blockade in this case is to implant a pacemaker.

Echocardiography, or ultrasound of the heart

Word echocardiography made up of three words: “echo”, “heart” and “image”. And it accurately characterizes the research method, which is based on capturing ultrasonic signals reflected from the tissues and structures of the heart. These signals are converted into an image on the monitor. The study allows the doctor to assess the size of the heart and its structures - the ventricles, atria, interventricular septa, the thickness of the myocardium of the ventricles and atria. Using ECHO (in other words, Ultrasound of the heart ) find out the condition of the heart valves, the condition of the pericardium and endocardium of the outer and inner cardiac membranes, respectively (read about various pathologies of heart structures in the following chapters).

Measurements and special calculations give an accurate idea of ​​the mass of the heart, its contractility, and the volume of blood ejected. ECHO is used during heart surgery - special probes are inserted through the vessels to monitor the functioning of the heart valves. Today, cardiologists have several types of echocardiographic studies available. One type allows you to analyze the movement of heart structures (atria, ventricles, valves) in real time. The other allows you to determine the speed of blood movement and turbulence of blood flow ( Doppler echocardiography ). It is believed that ECHO is complete if the Doppler method is used to determine the speed of blood flow in different parts of the heart and blood vessels.

Unfortunately, ECHO cannot be performed on patients suffering from obesity and emphysema ( various lesions lungs, leading to their excessive filling with air).

What is determined using Doppler echocardiography

The heart research technique gets its name from the Doppler effect. The effect was discovered in the field of physics, and its essence is as follows. If an ultrasonic wave is reflected from a moving structure, the frequency of the wave changes: as soon as the structure approaches the sensor, the speed increases, and as it moves away, it decreases. And the faster the object moves, the more the frequency of the wave changes.

In general, nothing complicated, but a lot of benefits for cardiology! After all, blood flow is the very structure whose speed must be determined.

With the help of ECHO, such disorders can be diagnosed.

Changes in the thickness and disturbance of the movement of the valves, which lead to their stenosis, prolapse, insufficiency ( Chapter 3/Acquired heart defects).

Valve stenosis caused by changes in the leaflets, the formation of adhesions, thickening or shortening of the chords (connecting elements).

Rheumatic deformities, endocarditis ( Chapter 2 / Inflammation inner shell hearts).

Congenital defects, cardiomyopathies ( Chapter 3 / Congenital heart defects).

Most neoplasms (tumors) involve the heart and pericardium (the outer lining of the heart).

What does blood biochemistry tell you about arrhythmias?

In case of persistent arrhythmia, a general blood test is performed to determine the hemoglobin content. If hemoglobin levels are low, the concentration of iron in the blood is additionally examined. Be sure to do a biochemical blood test for the content of electrolytes such as potassium, magnesium, calcium. The lack of these elements in the body can provoke arrhythmia. In severe attacks of arrhythmia and angina, the content of individual enzymes and organic accelerators of biochemical processes is determined. This allows you to clarify the diagnosis. Now let’s look one by one at what each indicator provides.

Hemoglobin

Hemoglobin – This is a red iron-containing blood pigment, it is the main component of erythrocytes, red blood cells. Hemoglobin delivers oxygen to the body's cells, and carbon dioxide carries for cleaning. Reduced hemoglobin in iron deficiency anemia provokes tachycardia, since the heart has to work faster to properly supply tissues with oxygen. Imagine the difficult situation the myocardium finds itself in if it itself suffers from a lack of oxygen.

Normally, men's blood contains hemoglobin in the amount of 130 – 160 g/l, in women the figure is below 120 – 140 g/l (in the new standards, respectively, 12 – 14 and 13 – 16 g%).

Potassium takes an important part in a number of processes occurring in our organs and tissues. Among these processes: normalization of heart rate and maintenance of normal blood pressure; adjustment water balance; influence on the functioning of muscles (including the myocardium) and nerve fibers. There is no potassium reserve in the body – this must be remembered. All of the above functions will be reduced as a result of potassium deficiency. However, excess potassium can provoke ventricular tachycardia. However, excessive accumulation of potassium in the blood is not associated with mindless overeating of potassium-containing foods (these are dried fruits for the most part), but with abnormal metabolism. If an excess is detected, then consumption adjustment will be required. Potassium content norm 3.5 – 5.5 mmol/l.

A lot can be said about the role of calcium in our body. Besides the fact that calcium – an element of bone tissue, it is involved in muscle contraction, blood clotting, iron absorption, and regulates heart rhythm. Calcium content norm 2.2 – 2.55 mmol/l.

Magnesium takes an active part in the work of the heart. With its help, the anti-stress mechanism is controlled and heart attacks are prevented. The normal magnesium content is 0.65–1.03 mmol/l.

If you are prescribed a blood test for magnesium levels, you should prepare for it. A week before blood sampling, stop taking magnesium-containing drugs, which are prescribed preventively for tachycardia. On the day before blood sampling, you should avoid alcohol and reduce physical activity.

Iron ions are part of blood hemoglobin. The main processes in which iron is involved are respiration and hematopoiesis. A deficiency of iron in hemoglobin is called iron deficiency anemia. It is characterized by shortness of breath, palpitations, muscle weakness, and many other problems. The norm of iron content depends on the norm of hemoglobin (that is, age, gender and even body type are taken into account). The need for iron entering the body in women is 2 times higher than the need in men due to menstrual blood loss. By the way, women are susceptible to functional tachycardia much more often than men. Iron content standards are 8.95–28.7 µmol/l (for men) and 7.16–26.85 µmol/l (for women).

Preparation for a blood test for iron content is as follows: if iron-containing drugs were previously prescribed, you should stop taking them a week before the blood draw.

Chapter 2. Can we carry the flu on our feet? No, on the heart!

People have been suffering from heart pathologies since ancient times. The history of medical science has an invaluable opportunity to study Egyptian mummies. Their computer study showed that heart disease was common in Egypt, despite living in harmony with nature at the time. Egyptian healers foresaw the importance of the heart in the body. In the so-called Esbers papyrus (a German Egyptologist named Georg Esbers), dating from the 17th century BC. there is an entry: “The beginning of the secrets of a doctor is knowledge of the course of the heart, from which vessels go to all members, for every doctor, every priest of the goddess Sokhmet, every spellcaster, touching the head, back of the head, arms, palms, legs, touches the heart everywhere. Vessels are directed from it to each member...”

But only 12 centuries later, the great Hippocrates described the structure of the heart as a muscular organ. He formed a concept of cardiac ventricles and large vessels leaving the heart close to reality.

If today you hear from a cardiologist about Purkinje fibers or the atrioventricular bundle of His, this is a very recent story. At the end of the 19th century, the Czech physiologist Jan Evangelista Purkinje studied specific muscle fibers that conduct excitation throughout the heart. This is how the conduction system of the heart was discovered. Over the next 50 years, the pacemakers we talked about in Chapter 1 / Every person experiences arrhythmia. Interestingly, the first order pacemaker (the sinus node, which we have already talked about quite a lot) was the last to open!

Here is an introductory fragment of the book.

Only part of the text is open for free reading (restriction of the copyright holder). If you liked the book, the full text can be obtained on our partner's website.

pages: 1 2 3 4 5 6 7 8 9 10 11 12

MINISTRY OF HEALTH OF THE RF

NIZHNY NOVGOROD STATE

MEDICAL INSTITUTE

A.V. SUVOROV

Publishing house NGMI NIZHNY NOVGOROD, 1993

Kyiv – 1999

UDC 616.12–008.3–073.96

Suvorov A.V. Clinical electrocardiography. – Nizhny Novgo-

genus. Publishing house NMI, 1993. 124 p. Ill.

The book by Suvorov A.V. is a good, complete textbook for cardiologists, therapists and senior students of medical institutes on all sections of electrocardiography. The features of ECG recording, normal ECG in standard and unipolar leads, all types of atrioventricular blocks, bundle branch blocks, ECG features in hypertrophies, conduction disorders, arrhythmias, myocardial infarction, ischemic heart disease, thromboembolism, cerebrovascular accidents, etc. are described in detail.

Published by decision of the editorial and publishing council of NMI

Scientific editor Professor S. S. BELOUSOV

Reviewer Professor A. A. OBUKHOVA

ISBN 5-7032-0029-6

© Suvorov A.V., 1993

PREFACE

Electrocardiography is one of the informative and most common methods of examining patients with heart disease. An ECG also makes it possible to diagnose diseases and syndromes that require emergency cardiac care, and above all myocardial infarction, paroxysmal tachyarrhythmias, conduction disorders with Morgagni–Edams–Stokes syndrome, etc. The need for their diagnosis arises at any time of the day, but, unfortunately, interpretation ECG presents significant difficulties for many doctors, and the reason for this is poor study of the method at the institute, and the lack of courses on ECG diagnostics at advanced training faculties for doctors. It is very difficult to acquire literature on clinical electrocardiography. The author sought to fill this gap.

The manual on electrocardiography is structured traditionally: first, the electrophysiological foundations of electrocardiography are briefly outlined, and the section is presented in detail normal ECG in standard, single-pole and chest leads, electrical position of the heart. The section “ECG for myocardial hypertrophy” describes general signs and criteria for atrial and ventricular hypertrophy.

When describing rhythm and conduction disorders, the pathogenetic mechanisms of the development of syndromes, clinical manifestations and medical tactics are presented.

The sections on ECG diagnosis of coronary artery disease, especially myocardial infarction, as well as infarction-like diseases, which are of great importance for practice, are covered in detail.

For complex ECG syndromes, a diagnostic search algorithm has been developed to facilitate the diagnosis of pathology.

The book is intended for doctors who want to study the theory and practice of this important area of ​​cardiology on their own or with the help of a teacher in a short time.

1. TECHNIQUE FOR REMOVING ELECTROCARDIOGRAM

The electrocardiogram is recorded using electrocardiographs. They can be single-channel or multi-channel. All electrocardiographs (Fig. 1) consist of an input device (1), an amplifier of cardiac biopotentials (2) and a recording device (3).

The input device is a lead switch with cables of different colors extending from it.

The amplifiers have a complex electronic circuit that allows them to enhance the biopotentials of the heart several hundred times. The power source for the amplifier can be batteries or AC power. For safety reasons when working with an electrocardiograph and to prevent interference, the device must be grounded using a wire, one end of which is attached to a special terminal of the electrocardiograph, and the other to a special circuit. If this is not available, in emergency cases, central heating water pipes can be used for grounding (as an exception).

The recording device converts electrical vibrations into mechanical ones. Mechanical pen recording is carried out using ink or carbon paper. Recently, thermal recording has become widespread.

The point is that a feather heated by electric current melts the fusible layer of the tape, exposing the black base.

To record an ECG, the patient is placed on a couch. For getting good contact Place gauze pads moistened under the electrodes. saline solution. Electrodes are applied to the inner surfaces of the lower third of the upper and lower extremities, a red cable is connected to the right arm, a black cable (patient grounding) to the right leg, a yellow cable to the left arm and a green cable to the left lower extremity. The pear-shaped chest electrode with a suction cup is connected to a white cable and installed in specific positions on the chest.

ECG recording begins with a reference millivolt, which should be equal to 10 mm.

IN 12 leads are recorded without fail - three standard, three unipolar and six chest leads, III, avF leads should preferably be taken in the inhalation phase. Additional leads are recorded according to indications.

IN Each lead should record at least 5 QRS complexes; for arrhythmias, one of the leads (II) is recorded on a long tape. The standard recording speed is 50 mm/sec; for arrhythmias, a speed of 25 mm/sec is used to reduce paper consumption. The voltage of the QRS complexes can be increased and decreased by 2 times depending on the research task.

An application for an ECG study is written on a special form or in a journal, which indicates the full name, gender, blood pressure, age of the patient, and diagnosis. It is imperative to report any medications you are taking.

therapy with cardiac glycosides, β-blockers. diuretics, electrolytes, antiarrhythmic drugs of the quinidine series, rauwolfia, etc.

2. ELECTROPHYSIOLOGICAL BASICS OF ELECTROCARDIOGRAPHY

Heart is hollow muscular organ, divided by a longitudinal septum into two halves: left arterial and right venous. The transverse septum divides each half of the heart into two sections: the atrium and the ventricle. The heart performs certain functions: automaticity, excitability, conductivity and contractility.

Automaticity is the ability of the conduction system of the heart to independently produce impulses. To the greatest extent the function

The sinus node (the center of first-order automaticity) has automaticity. At rest, it produces 60–80 impulses per minute. In case of pathology, the source of rhythm can be the atrioventricular node (the center of second-order automaticity); it produces 40–60 impulses per minute.

The conduction system of the ventricles (idioventricular rhythm) also has an automatic function. However, only 20–50 impulses are generated per minute (third-order center of automaticity).

Excitability is the ability of the heart to respond by contraction to internal and external stimuli. Normally, excitation and contraction of the heart occur under the influence of impulses from the sinus node.

Impulses can be not only nomotopic (from the sinus node), but also heterotopic (from other parts of the conduction system of the heart). If the heart muscle is in a state of excitation, it does not respond to other impulses (absolute or relative refractory phase). Therefore, the heart muscle cannot be in a state of tetanic contraction. When the myocardium is excited, an electromotive force appears in it in the form of vector quantities, which is recorded in the form of an electrocardiogram.

Conductivity. Having originated in the sinus node, the impulse spreads orthograde through the atrial myocardium, then through the atrioventricular node, the His bundle, and the ventricular conduction system. The intraventricular conduction system includes the right branch of the His bundle, the main trunk of the left branch of the His bundle and its two branches, anterior and posterior, and ends with the Purkinje fibers, which transmit impulses to the cells of the contractile myocardium (Fig. 2).

The speed of propagation of the excitation wave in the atria is 1 m/sec, in the ventricular conduction system 4 m/sec, and in the atrioventricular node 0.15 m/sec. Retrograde impulse conduction is sharply slowed down, atrioventricular delay allows the atria to contract before the ventricles. The most vulnerable areas of the conduction system are: atrioventricular node with AV delay, right bundle branch, left anterior branch,

As a result of the impulse, the process of excitation (depolarization) of the myocardium begins at the beginning of the interventricular septum, right and left ventricles. Excitation of the right ventricle may begin earlier (0.02"") than the left. Subsequently, depolarization captures the myocardium of both ventricles, and the electromotive force (total vector) of the left ventricle is greater than the right one.

th. The process of depolarization proceeds from the apex to the base of the heart, from the endocardium to the epicardium.

The process of recovery (repolarization) of the myocardium begins at the epicardium and spreads to the endocardium. During repolarization, a significantly lower electromotive force (EMF) occurs than during depolarization.

The process of depolarization and repolarization of the myocardium is accompanied by bioelectric phenomena. It is known that the protein-lipid membrane of the cell has the properties of a semi-permeable membrane. K+ ions easily penetrate through the membrane and phosphates, sulfates, and proteins do not penetrate. Since these ions are negatively charged,

they attract positively charged K+ ions. The concentration of K+ ions inside the cell is 30 times higher than in the extracellular fluid. Nevertheless, negative charges predominate on the inner surface of the membrane. Na+ ions are located predominantly on outer surface membranes, because the cell membrane at rest is poorly permeable to Na+. The Na+ concentration in the extracellular fluid is 20 times higher than inside the cell. The cell potential at rest is approximately

but 70–90 mV.

When the myocardium is depolarized, the permeability of cell membranes changes, sodium ions easily penetrate the cell and change the charge of the inner surface of the membrane. Due to the fact that Na+ enters the cell, the electrical charge on the outer surface of the membrane changes. Depolarization changes the charge on the outer and inner surfaces of cell membranes. The potential difference that occurs during excitation is called the action potential, it is about 120 mV. During the process of repolarization, K+ ions leave the cell and restore the resting potential. Upon completion of repolarization, Na+ is removed from the cell into the extracellular space using sodium pumps, and K+ ions actively penetrate into the cell through the semi-permeable cell membrane (Fig. 3).

The repolarization process proceeds more slowly than depolarization and causes less emf than the excitation process.

Repolarization begins in the subepicardial layers and ends in the subendocardial layers.

The process of depolarization in a muscle fiber is more complex than in an individual cell. The excited area is charged negatively in relation to the area at rest, and dipole charges are formed, equal in magnitude and opposite in direction. If a dipole with a positive charge moves towards the electrode, a positively directed tooth is formed, if from the electric

troda – negatively directed.

The human heart contains many muscle fibers. Each excited fiber represents a dipole. Dipoles move in different directions. The sum of the vectors of muscle fibers of the right and left ventricles is written as a scalar quantity

– electrocardiograms.

IN In each lead, the ECG curve represents the sum of the vectors of the right and left ventricles and atria (biocardiogram theory).

3. NORMAL ECG IN STANDARD LEADS

IN At the beginning of the 20th century, Einthoven proposed standard leads. Einthoven presented the human body in the form of an equilateral triangle. The first standard lead registers the potential difference between the right and left hands, the second – the potential difference right hand and the left leg, the third is the potential difference between the left arm and left leg. According to Kirchhoff's law, the second lead represents the algebraic sum of the first and third leads. All elements of the electrocardiogram obey this rule. The first lead reflects the potentials of the subepicardial surface of the left ventricle, the third – the potentials back wall the left ventricle and the subepicardial surface of the right ventricle.

A normal ECG in standard leads is represented by a series of waves and intervals, designated by Latin letters (Fig. 4). If the amplitude of the tooth is more than 5 mm, it is indicated by a capital letter, if less than 5 mm, then by a small letter.

Wave P - this atrial complex consists of a hollow ascending limb and a symmetrically located descending limb, which are connected by a rounded apex. The duration (width) of the tooth does not exceed 0.08-0.1 seconds (1 mm - 0.02 ""), the height P is 0.5-2.5 mm. The largest amplitude P in

second standard lead. Normally PII >PI >PIII. PI >0.l"" indicates hypertrophy of the left atrium; with PIII >2.5 mm we can speak of hypertrophy of the right atrium. The duration of the P wave is measured from the beginning of the ascending to the end of the descending knee, the amplitude

P - from the base of the tooth to its top.

Interval PQ (R) – from the beginning of P to the beginning of g or R. It corresponds to the time of passage of the impulse through the atria, through the atrioventricular node, along the His bundle, bundle branches, and Purkinje fibers.

The duration of the PQ interval normally fluctuates 0.12"÷ 0.20"" and depends on the pulse rate. Prolongation of the PQ interval is observed when atrioventricular conduction is impaired; shortening of PQ is associated with a sympatheticoadrenal reaction, premature ventricular excitation syndrome, atrial or nodal pacemaker, etc.

Segment PQ – located from the end of P to the beginning of Q (R). The ratio of P to the PQ segment is called the Makruz index, its norm is 1.1–1.6. An increase in the Macruse index indicates hypertrophy of the left atrium.

The QRS complex reflects the process of ventricular depolarization, measured in the second standard lead from the beginning of Q to the end of S, the normal duration is 0.05–0.1 "". QRS prolongation is associated with myocardial hypertrophy or intraventricular conduction disturbances.

The Q wave is associated with the excitation of the interventricular septum (optional, with a negative amplitude). The duration of Q in the first and second standard leads is up to 0.03"", in the third standard lead - up to 0.04". The amplitude of Q is normally no more than 2 mm or no more than 25% R. Widening of Q and its increase indicate the presence of focal changes in the myocardium.

The R wave is caused by ventricular depolarization, has an ascending limb, an apex, and a descending limb. The time from Q (R) to the perpendicular from the apex of R indicates an increase in the rate of depolarization of the ventricles and is called the time of internal deviation, for the left ventricle no more than 0.04"", for the right - 0.035"". Serration R

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Electrocardiogram is a widely used method of objective diagnostics various pathologies of the human heart, which is used almost everywhere today. An electrocardiogram (ECG) is taken in a clinic, in an ambulance, or in a hospital department. ECG is a very important recording that reflects the condition of the heart. That is why the reflection of various types of cardiac pathology on the ECG is described by a separate science - electrocardiography. Electrocardiography also deals with the problems of correct ECG recording, decoding issues, interpretation of controversial and unclear points, etc.

Definition and essence of the method

An electrocardiogram is a recording of the heart, which is presented as a curved line on paper. The cardiogram line itself is not chaotic; it has certain intervals, teeth and segments that correspond to certain stages of the heart.

To understand the essence of an electrocardiogram, you need to know what exactly is recorded by a device called an electrocardiograph. The ECG records the electrical activity of the heart, which changes cyclically in accordance with the onset of diastole and systole. The electrical activity of the human heart may seem like fiction, but this unique biological phenomenon exists in reality. In reality, the heart contains so-called cells of the conduction system, which generate electrical impulses that are transmitted to the muscles of the organ. It is these electrical impulses that cause the myocardium to contract and relax with a certain rhythm and frequency.

The electrical impulse propagates through the cells of the conduction system of the heart strictly sequentially, causing contraction and relaxation of the corresponding sections - the ventricles and atria. The electrocardiogram reflects precisely the total electrical potential difference in the heart.

decryption?

An electrocardiogram can be taken in any clinic or multidisciplinary hospital. You can contact a private medical center where there is a specialist cardiologist or therapist. After recording the cardiogram, the tape with curves is examined by the doctor. It is he who analyzes the recording, deciphers it and writes a final report, which reflects all visible pathologies and functional deviations from the norm.

An electrocardiogram is recorded using a special device - an electrocardiograph, which can be multi-channel or single-channel. The speed of ECG recording depends on the modification and modernity of the device. Modern devices can be connected to a computer, which, with a special program, will analyze the recording and issue a final conclusion immediately after the procedure is completed.

Any cardiograph has special electrodes that are applied in a strictly defined order. There are four clothespins in red, yellow, green and black that are placed on both arms and both legs. If you go in a circle, then the clothespins are applied according to the rule “red-yellow-green-black”, from the right hand. It's easy to remember this sequence thanks to the student saying: "Every-Woman is an Eviler Trait." In addition to these electrodes, there are also chest electrodes, which are installed in the intercostal spaces.

As a result, the electrocardiogram consists of twelve waveforms, six of which are recorded from the chest electrodes, and are called chest leads. The remaining six leads are recorded from electrodes attached to the arms and legs, with three of them called standard and three more called enhanced. The chest leads are designated V1, V2, V3, V4, V5, V6, the standard ones are simply Roman numerals - I, II, III, and the reinforced leg leads - the letters aVL, aVR, aVF. Different leads of the cardiogram are necessary to create the most complete picture of the activity of the heart, since some pathologies are visible on the chest leads, others on the standard ones, and still others on the enhanced ones.

The person lies down on the couch, the doctor attaches the electrodes and turns on the device. While the ECG is being written, the person must be absolutely calm. We must not allow the appearance of any irritants that can distort the true picture of the work of the heart.

How to correctly perform an electrocardiogram followed by
transcript - video

The principle of decoding an ECG

Since the electrocardiogram reflects the processes of contraction and relaxation of the myocardium, it is possible to trace how these processes occur and identify existing pathological processes. The elements of the electrocardiogram are closely related and reflect the duration of the phases of the cardiac cycle - systole and diastole, that is, contraction and subsequent relaxation. Decoding the electrocardiogram is based on the study of the teeth, their position relative to each other, duration, and other parameters. The following elements of the electrocardiogram are studied for analysis:
1. Teeth.
2. Intervals.
3. Segments.

All sharp and smooth convexities and concavities on the ECG line are called teeth. Each tooth is designated by a letter of the Latin alphabet. The P wave reflects contraction of the atria, the QRS complex – contraction of the ventricles of the heart, the T wave – relaxation of the ventricles. Sometimes after the T wave on the electrocardiogram there is another U wave, but it has no clinical and diagnostic role.

An ECG segment is considered to be a segment enclosed between adjacent teeth. For diagnosing heart pathology, the P – Q and S – T segments are of great importance. The interval on the electrocardiogram is a complex that includes a tooth and an interval. The P–Q and Q–T intervals are of great importance for diagnosis.

Often in the doctor’s report you can see small Latin letters, which also indicate teeth, intervals and segments. Small letters are used if the prong is less than 5 mm long. In addition, several R waves may appear in the QRS complex, which are usually designated R’, R”, etc. Sometimes the R wave is simply missing. Then the entire complex is designated by only two letters - QS. All this has important diagnostic value.

ECG interpretation plan - general scheme for reading results

When deciphering an electrocardiogram, the following parameters reflecting the work of the heart must be established:

• position of the electrical axis of the heart;
• determining the correctness of the heart rhythm and conductivity of the electrical impulse (blockades, arrhythmias are identified);
• determining the regularity of contractions of the heart muscle;
• determination of heart rate;
• identifying the source of the electrical impulse (whether sinus rhythm is determined or not);
• analysis of the duration, depth and width of the atrial P wave and the P – Q interval;
• analysis of the duration, depth, width of the QRST ventricular wave complex;
• analysis of parameters of the RS – T segment and T wave;
• analysis of Q – T interval parameters.

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

In the conclusion on the electrocardiogram, the doctor must reflect the following parameters:

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

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

Example of deciphering an electrocardiogram

At the very beginning of the electrocardiogram tape there should be a calibration signal, which looks like a large letter “P” 10 mm high. If this calibration signal is not present, then the electrocardiogram is uninformative. If the height of the calibration signal is below 5 mm in standard and enhanced leads, and below 8 mm in chest leads, then there is a low voltage of the electrocardiogram, which is a sign of a number of heart pathologies. For subsequent decoding and calculation of some parameters, you need to know what period of time fits into one cell of graph paper. At a belt speed of 25 mm/s, one cell 1 mm long is equal to 0.04 seconds, and at a speed of 50 mm/s – 0.02 seconds.

Checking the regularity of heart contractions

It is assessed by the intervals R - R. If the teeth are located at the same distance from each other throughout the entire recording, then the rhythm is regular. Otherwise it is called correct. Estimating the distance between the R - R teeth is very simple: the electrocardiogram is recorded on graph paper, which makes it easy to measure any gaps in millimeters.

Heart rate (HR) calculation

It is carried out using a simple arithmetic method: count the number of large squares on graph paper that are placed between two R waves. Then the heart rate is calculated using the formula, which is determined by the speed of the tape in the cardiograph:
1. The tape speed is 50 mm/s - then the heart rate is 600 divided by the number of squares.
2. The tape speed is 25 mm/s - then the heart rate is 300 divided by the number of squares.

For example, if 4.8 large squares fit between two R teeth, then the heart rate, at a belt speed of 50 mm/s, will be equal to 600/4.8 = 125 beats per minute.

If the heart rate is abnormal, then the maximum and minimum heart rate is determined, also taking as a basis the maximum and minimum distances between the R waves.

Identifying the source of the rhythm

The doctor studies the rhythm of heart contractions and finds out which node nerve cells causes cyclic processes of contraction and relaxation of the heart muscle. This is very important for identifying blockages.

Decoding ECG - rhythms

Normally, the pacemaker is the sinus node. And such a normal rhythm itself is called sinus - all other options are pathological. In various pathologies, any other node of the nerve cells of the cardiac conduction system can act as a pacemaker. In this case, the cyclic electrical impulses become confused and the heart rhythm is disrupted - arrhythmia occurs.

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

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

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

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

Detection of pathology of electrical impulse conduction through the structures of the heart

To do this, measure the duration of the P wave, the P–Q interval and the QRS complex. The duration of these parameters is calculated from the millimeter tape on which the cardiogram is recorded. First, count how many millimeters each tooth or interval occupies, after which the resulting value is multiplied by 0.02 at a recording speed of 50 mm/s, or by 0.04 at a recording speed of 25 mm/s.

The normal duration of the P wave is up to 0.1 seconds, the P – Q interval is 0.12-0.2 seconds, the QRS complex is 0.06-0.1 seconds.

Electrical axis of the heart

Denoted as the alpha angle. It can have a normal position, horizontal or vertical. Moreover, in a thin person the axis of the heart is more vertical relative to the average values, while in a fat person it is more horizontal. The normal position of the electrical axis of the heart is 30–69 o, vertical – 70–90 o, horizontal – 0–29 o. The alpha angle, equal to 91 to ±180 o, reflects a sharp deviation of the electrical axis of the heart to the right. The alpha angle, equal to 0 to –90 o, reflects a sharp deviation of the electrical axis of the heart to the left.

The electrical axis of the heart can deviate under various pathological conditions. For example, hypertension leads to a deviation to the right; a conduction disorder (blockade) can shift it to the right or left.

Atrial P wave

The atrial P wave should be:

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

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

Pathological forms of the P wave may indicate the following pathologies:
1. Tall and sharp teeth in leads II, III, aVF appear with hypertrophy of the right atrium (“cor pulmonale”);
2. A P wave with two peaks and a large width in leads I, aVL, V5 and V6 indicates hypertrophy of the left atrium (for example, mitral valve disease).

P–Q interval

The P–Q interval has a normal duration of 0.12 to 0.2 seconds. An increase in the duration of the P–Q interval is a reflection of atrioventricular block. On the electrocardiogram, three degrees of atrioventricular block (AV) can be distinguished:

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

Ventricular QRST complex

The ventricular QRST complex consists of the QRS complex itself and the S – T segment. The normal duration of the QRST complex does not exceed 0.1 seconds, and its increase is detected with blockades of the Hiss bundle branches.

QRS complex consists of three waves, Q, R and S, respectively. The Q wave is visible on the cardiogram in all leads except 1, 2 and 3 chest leads. A normal Q wave has an amplitude up to 25% of that of an R wave. The duration of the Q wave is 0.03 seconds. The R wave is recorded in absolutely all leads. The S wave is also visible in all leads, but its amplitude decreases from the 1st thoracic to the 4th, and in the 5th and 6th it may be completely absent. The maximum amplitude of this tooth is 20 mm.

The S–T segment is very important from a diagnostic point of view. It is by this tooth that myocardial ischemia can be detected, that is, a lack of oxygen in the heart muscle. Usually this segment runs along the isoline, in the 1st, 2nd and 3rd chest leads; it can rise up by a maximum of 2 mm. And in the 4th, 5th and 6th chest leads, the S-T segment can shift below the isoline by a maximum of half a millimeter. It is the deviation of the segment from the isoline that reflects the presence of myocardial ischemia.

T wave

The T wave is a reflection of the process of eventual relaxation in the cardiac muscle of the ventricles of the heart. Typically, when the amplitude of the R wave is large, the T wave will also be positive. A negative T wave is normally recorded only in lead aVR.

Q-T interval

The Q–T interval reflects the process of eventual contraction in the myocardium of the ventricles of the heart.

ECG interpretation - normal indicators

The transcript of the electrocardiogram is usually recorded by the doctor in conclusion. A typical example of a normal cardiac cardiogram looks like this:
1. PQ – 0.12 s.
2. QRS – 0.06 s.
3. QT – 0.31 s.
4. RR – 0.62 – 0.66 – 0.6.
5. Heart rate is 70 - 75 beats per minute.
6. sinus rhythm.
7. The electrical axis of the heart is located normally.

Normally, the rhythm should be only sinus, the heart rate of an adult is 60 - 90 beats per minute. The P wave is normally no more than 0.1 s, the P – Q interval is 0.12-0.2 seconds, the QRS complex is 0.06-0.1 seconds, Q – T is up to 0.4 s.

If the cardiogram is pathological, then it indicates specific syndromes and deviations from the norm (for example, partial blockade of the left bundle branch, myocardial ischemia, etc.). The doctor can also reflect specific violations and changes in the normal parameters of the waves, intervals and segments (for example, shortening of the P wave or Q-T interval, etc.).

Interpretation of ECG in children and pregnant women

In principle, children and pregnant women have normal heart electrocardiogram readings - the same as in healthy adults. However, there are certain physiological characteristics. For example, the heart rate of children is higher than that of an adult. The normal heart rate of a child up to 3 years of age is 100–110 beats per minute, 3–5 years old – 90–100 beats per minute. Then gradually the heart rate decreases, and in adolescence it is compared with that of an adult - 60 - 90 beats per minute.

In pregnant women, there may be a slight deviation of the electrical axis of the heart in late gestation due to compression by the growing uterus. In addition, sinus tachycardia often develops, that is, an increase in heart rate to 110 - 120 beats per minute, which is functional state, and goes away on its own. An increase in heart rate is associated with a greater volume of circulating blood and increased workload. Due to the increased load on the heart, pregnant women may experience overload in various parts of the organ. These phenomena are not a pathology - they are associated with pregnancy and will go away on their own after childbirth.

Decoding the electrocardiogram during a heart attack

Myocardial infarction is a sudden cessation of oxygen supply to the heart muscle cells, resulting in the development of necrosis of a tissue area that is in a state of hypoxia. The reason for the disruption of oxygen supply can be different - most often it is a blockage of a blood vessel, or its rupture. A heart attack affects only part of muscle tissue heart, and the extent of the damage depends on the size of the blood vessel that is blocked or ruptured. On an electrocardiogram, myocardial infarction has certain signs by which it can be diagnosed.

In the process of development of myocardial infarction, four stages are distinguished, which have different manifestations on ECG:

• acute;
• acute;
• subacute;
• cicatricial.

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

Sometimes it is possible to detect the phase of myocardial ischemia preceding the acute phase, which is characterized by high T waves.

Acute stage A heart attack lasts 2–3 weeks. During this period, a wide and high-amplitude Q wave and a negative T wave are recorded on the ECG.

Subacute stage lasts up to 3 months. The ECG shows a very large negative T wave with a huge amplitude, which gradually normalizes. Sometimes a rise in the S-T segment is detected, which should have leveled off by this period. This is an alarming symptom, as it may indicate the formation of a cardiac aneurysm.

Scar stage heart attack is final, since connective tissue is formed at the damaged site, incapable of contraction. This scar is recorded on the ECG as a Q wave, which will remain for life. Often the T wave is smoothed, has a low amplitude, or is completely negative.

Interpretation of the most common ECGs

In conclusion, doctors write the result of the ECG interpretation, which is often incomprehensible because it consists of terms, syndromes and simply statements of pathophysiological processes. Let's consider the most common ECG conclusions, which are incomprehensible to a person without a medical education.

Ectopic rhythm means not sinus - which can be either a pathology or a norm. The norm ectopic rhythm occurs when there is congenital malformation of the conduction system of the heart, but the person does not present any complaints and does not suffer from other cardiac pathologies. In other cases, an ectopic rhythm indicates the presence of blockades.

Changes in repolarization processes on the ECG reflects a violation of the process of relaxation of the heart muscle after contraction.

Sinus rhythm This is the normal heart rate of a healthy person.

Sinus or sinusoidal tachycardia means that a person has a correct and regular rhythm, but an increased heart rate - more than 90 beats per minute. In young people under 30 years of age, this is a variant of the norm.

Sinus bradycardia- this is a low heart rate - less than 60 beats per minute against the background of a normal, regular rhythm.

Nonspecific ST-T changes mean that there are minor deviations from the norm, but their cause may be completely unrelated to heart pathology. It is necessary to undergo a full examination. Such nonspecific ST-T changes can develop with an imbalance of potassium, sodium, chlorine, magnesium ions, or various endocrine disorders, often during menopause in women.

Biphasic R wave in combination with other signs of a heart attack indicates damage to the anterior wall of the myocardium. If no other signs of a heart attack are detected, then a biphasic R wave is not a sign of pathology.

QT prolongation may indicate hypoxia (lack of oxygen), rickets, or overexcitation of the child’s nervous system, which is a consequence of birth trauma.

Myocardial hypertrophy means that the muscular wall of the heart is thickened and works under enormous load. This can lead to the formation of:

• heart failure;
• arrhythmias.

Also, myocardial hypertrophy can be a consequence of previous heart attacks.

Moderate diffuse changes in the myocardium mean that tissue nutrition is impaired and cardiac muscle dystrophy has developed. This is a fixable condition: you need to see a doctor and undergo an adequate course of treatment, including normalizing your diet.

Deviation of the electrical axis of the heart (EOS) left or right is possible with hypertrophy of the left or right ventricle, respectively. EOS can deviate to the left in obese people, and to the right - in thin people, but in this case this is a variant of the norm.

Left type ECG– EOS deviation to the left.

NBPNG– an abbreviation for “incomplete right bundle branch block.” This condition can occur in newborns and is a normal variant. In rare cases, RBBB can cause arrhythmia, but generally does not lead to the development of negative consequences. Block of the Hiss bundle branch is quite common in people, but if there are no complaints about the heart, then it is not at all dangerous.

BPVLNPG– an abbreviation meaning “blockade of the anterior branch of the left bundle branch.” Reflects a violation of the conduction of electrical impulses in the heart, and leads to the development of arrhythmias.

Small growth of the R wave in V1-V3 may be a sign of interventricular septal infarction. To accurately determine whether this is the case, it is necessary to do another ECG study.

CLC syndrome(Klein-Levy-Kritesco syndrome) is a congenital feature of the conduction system of the heart. May cause the development of arrhythmias. This syndrome does not require treatment, but it is necessary to be regularly examined by a cardiologist.

Low voltage ECG often recorded with pericarditis ( large volume connective tissue in the heart, replacing muscle tissue). In addition, this sign may be a reflection of exhaustion or myxedema.

Metabolic changes are a reflection of insufficient nutrition of the heart muscle. It is necessary to be examined by a cardiologist and undergo a course of treatment.

Conduction slowdown means that the nerve impulse travels through the tissues of the heart more slowly than normal. This condition itself does not require special treatment - it may be a congenital feature of the conduction system of the heart. Regular monitoring by a cardiologist is recommended.

Blockade 2 and 3 degrees reflects a serious disturbance of cardiac conduction, which is manifested by arrhythmia. In this case, treatment is necessary.

Rotation of the heart by the right ventricle forward may be an indirect sign of the development of hypertrophy. In this case, it is necessary to find out its cause and undergo a course of treatment, or adjust your diet and lifestyle.

Price of an electrocardiogram with interpretation

The cost of an electrocardiogram with interpretation varies significantly, depending on the specific medical institution. So, in public hospitals and in clinics, the minimum price for the procedure of taking an ECG and interpreting it by a doctor is from 300 rubles. In this case, you will receive films with recorded curves and a doctor’s conclusion on them, which he will make himself, or using a computer program.

If you want to receive a thorough and detailed conclusion on the electrocardiogram, a doctor’s explanation of all the parameters and changes, it is better to contact a private clinic that provides such services. Here the doctor will be able not only to write a conclusion after deciphering the cardiogram, but also to calmly talk to you, taking his time to explain all the points of interest. However, the cost of such a cardiogram with interpretation in a private medical center ranges from 800 rubles to 3,600 rubles. You should not assume that bad specialists work in an ordinary clinic or hospital - it’s just that a doctor in a public institution, as a rule, has a very large amount of work, so he simply does not have time to talk with each patient in great detail.

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

1. Heart rhythm: what is the state of the electrical impulse generators and the cardiac systems that conduct these impulses.
2. Heart 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 receive an electrocardiogram along with its results. It is impossible to decipher it yourself. To read the diagram, you will need special medical education. There is no need to be nervous before meeting with a functional diagnostician. At the appointment, he will explain all the risks of the diagnosis and prescribe effective treatment. But if the patient is diagnosed with a serious illness, then a consultation with a cardiologist will be required.

When the ECG interpretation does not give clear results, the doctor may prescribe additional studies:

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

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

On the ECG of a healthy person, the inscription “Sinus rhythm” is found. If a 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 an indicator of the rhythm of the sinus node, which is the main rhythm producer for regulating and generating electrical impulses with the help of which the heart muscle contracts. An electrocardiogram description that includes sinus rhythm is the norm, indicating the health of the sinus node and the heart muscle itself.



If the heart cardiogram does not have any other marks in its description, it indicates complete heart health. 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.



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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% sinus arrhythmias should be monitored by a cardiologist. Patients should be examined and re-tested every 3-4 months. Such precautions will protect you as much as possible from the development of more serious heart diseases.



Sinus bradycardia is a rhythm of heart contractions up to 50 times per minute. This phenomenon It is also possible in healthy people during sleep or in professional athletes. Bradycardia of a pathological nature may be a sign of sick sinus syndrome. This case implies severe bradycardia, reaching up to 35 heartbeats per minute. This pathology can be observed 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 disruption in the supply of oxygen to the tissues, which usually leads to fainting. Only an electrical pacemaker, 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.

The causes of a poor cardiogram may be associated with sinus tachycardia, which is a contraction of the heart rate more than 90 times per minute. It is divided into tachycardia of a physiological and pathological nature. Healthy people may experience sinus tachycardia during physical and emotional stress, drinking coffee or strong tea, alcoholic 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 fairly short time after reducing the intensity of physical activity.



With tachycardia of a pathological nature, a rapid heartbeat bothers the patient all the time. The cause of increased heart rate can be: increased body temperature, infection, blood loss, dehydration, anemia and more. The root cause causing tachycardia needs to be treated. Relief of sinus tachycardia occurs only in the case of myocardial infarction or acute coronary syndrome.



How does extrasystole manifest?

A specialist can identify this pathology immediately, since this is a change in rhythm, the nature of which is 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 heartbeat occurs due to nervous stress. Rhythm can be either rapid or slow, sometimes chaotic. The patient himself can notice the dips that occur in the rhythm of the heartbeat.

An example of decoding an ECG with extrasystole is an example of pathology that is visible even to non-specialists. Some patients complain not only of changes in rhythm, but also of unpleasant and painful sensations in the chest area. They experience tremors, tingling, and a sinking feeling of fear rising in their stomach.



Such manifestations are not always pathological and life-threatening.

Many types of extrasystoles do not inhibit blood circulation and do not reduce the performance of the heart.

Extrasystoles are divided into 2 types:

• functional (manifest against a 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 heart surgery. A single manifestation of extrasystole occurs rarely (up to 5 times in 1 hour). Such gaps are functional in nature and are not an obstacle to normal blood supply. There are moments 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. To accurately diagnose this manifestation, it is prescribed additional analysis ECG and Holter with installation for 24 hours.



Main classes of pathology

Extrasystoles also have the form of allorhythmia. When an extrasystole appears on every second contraction, experts diagnose bigeminy, on every third - trigeminy, on every fourth - quadrigeminy. According to Laum’s classification, extrasystoles of ventricular nature are divided into 5 classes depending on the daily examination indicators:

1. 1. Single cases of disease manifestations up to 60 times every hour, united by one focus (monotopic).
2. 2. Constant monotopic changes, occurring more than 5-6 times every minute.
3. 3. Constant polymorphic (have different shapes) and polytopic (have different centers of occurrence) changes.
4. 4. Paired or group, accompanied by episodic attacks of paroxysmal tachycardia.
5. 5. Early manifestation of extrasystoles.

No medications are prescribed for treatment. When the disease manifests itself less than 200 times a day (Holter monitoring will help establish the exact number), extrasystoles are considered safe, so there is no need to worry about their manifestations. Regular examinations by a cardiologist are required every 3 months.

If the patient’s electrocardiogram reveals 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. Treatment of manifestations is specific and requires special approach, since it is not the extrasystoles that are being treated, but the root causes of their occurrence.



Paroxysmal tachycardia

Paroxysm is a manifestation of an attack. This process of increased heart rate can last for several hours or several days. The electrocardiogram displays equal 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 distinguish supraventricular and ventricular types of tachycardia. The basis of this pathology is the abnormal circulation of electrical impulses in cardiovascular system. You can get rid of this manifestation at home, but for a while: you need to hold your breath, start coughing hysterically, or dip your face in cold water. But such methods are ineffective. Therefore there is medical method for the treatment of paroxysmal tachycardia.

One of the types 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 of an extra bundle of nerves between the atria and ventricles, which conducts the rhythm faster than the main driver. As a result, the heart contracts one extra time. This pathology can be treated conservatively or surgically. The operation is prescribed only in case of low effectiveness or the patient is allergic to the active components of treatment, in case of atrial fibrillation or heart defects of various types.

Clerk-Levy-Christesco syndrome is a manifestation similar to the previous pathology, but it is characterized by earlier than normal stimulation of the ventricles with the help of an additional bundle through which the nerve impulse passes. The syndrome is a 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 lengths between contractions. This is explained by the fact that the rhythm is set not by the sinus node, but by other cells of the atria. The frequency of contractions can reach even 700 beats in 1 minute. Full contraction of the atria is simply absent; it occurs due to muscle fibers, which do not allow the ventricles to be completely filled with blood. The consequence of this process is a deterioration in the heart’s output of blood, which leads to oxygen starvation of organs and tissues of all body systems.

Atrial fibrillation also has another name: atrial fibrillation. In fact, not all atrial contractions travel directly to the ventricles. This results in a decrease in the normal heart rate (bradysystole, which has a beat rate of less than 60 times per minute). But the heart contraction can be normal (normosystole, 60-90 times per minute) or increased (tachysystole, more than 90 times per minute).



Determining atrial fibrillation on an electrocardiogram is easy, since attacks are difficult to miss. The onset of an attack in 90% of cases is a strong shock to the heart muscle. Next, a series of arrhythmic oscillations of the heart develops with an increased or normal frequency. The patient's condition also worsens: he becomes weak, sweaty, and dizzy. The patient awakens to a pronounced fear of death. Shortness of breath and an agitated state may occur. Sometimes loss of consciousness occurs. Reading a cardiogram at the final stage of an attack is also easy: the rhythm returns to normal. But the patient feels desire to urination, during which enough comes out a large number of liquids.

The disease is relieved 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. Pulmonary embolism and stroke may occur.

A constant form of flicker, in which neither medications nor electrical stimulation of the heart helps, becomes commonplace in the patient’s life and is felt only during tachysystole (increased heart rate). If the electrocardiogram reveals 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 is constant and frequent contractions of the atria (more than 200 times per minute) and ventricles (less than 200 times). Flutter in 90% of cases has an acute form, but is tolerated much better 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. It is easy to read an ECG for this disease, as it is manifested by frequent rhythmic heartbeat, swollen veins in the neck, shortness of breath, increased sweating and weakness.



In the normal state, electrical excitation is generated in the sinus node, which passes through the conduction system. It experiences a physiological delay of literally a split second in the area of ​​the atrioventricular node. The atria and ventricles, whose function is to pump blood, are stimulated by this impulse. When an impulse is delayed in some part of the system, it reaches other areas of the heart later, which leads to disruptions in the normal operation of the pumping system. Changes in conductivity are called blockade.

The occurrence of blockades is a 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 block: the passage of an impulse directly from the sinus node is difficult. Then this blockade develops into sick sinus syndrome, leading to a decrease in the number of contractions until a new blockade occurs, impaired blood supply to the peripheral section, shortness of breath, weakness, dizziness and loss of consciousness.
2. 2. Samoilov-Wenckebach block - the second degree of sinoatrial block.
3. 3. Atrioventricular block is a delayed excitation of the atrioventricular node for more than 0.09 seconds. There are 3 degrees of blockade of this type. With the highest degree of disease, the ventricles contract more often. Therefore, at the highest stages, blood circulation disorders become more severe.

Conduction disturbances 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 conductivity of the electrical signal. Specialists can easily diagnose this deviation from the norm on an ECG. At the same time, the diagram clearly shows that one of the ventricles is stimulated later than the second, because the signaling is produced with a delay, passing along bypass paths due to the blockade of the desired area.



The blockade is classified not only by place of origin, 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 conduction: coronary disease, cardiomyopathy, defects of various types, fibrosis, cancer of the heart. The consumption of antiarrhythmic drugs, increased potassium levels in the blood, oxygen starvation, and more can affect the occurrence of the disease.

The most common blockage of the superior branch is on the left bundle branch. The second place is taken by the blockade of the entire area of ​​the right leg. It does not occur due to other heart diseases. Left leg block occurs when the myocardium is damaged by a number of diseases. The lower branch of the left leg suffers from pathological changes in the structure of the human chest. It can also occur when the right ventricle is overloaded.