The ECG is normal. Decoding the cardiogram of the heart. ECG - what is it?

Conduction system of the heart designed to provide the function of automaticity and conductivity, i.e. the ability to autonomously generate electrical impulses and spread the excitation they cause (depolarization) to all parts of the contractile myocardium. This system contains nodes and bundles (groups of specialized cells - pacemakers), in which electrical impulses and fibers are born, through which excitation moves, spreading to the contractile myocardium.

The greatest activity has a sinoauricular node (SA node). Under physiological conditions (at rest), it produces 60-80 impulses per minute. However, in certain situations, the pulse frequency can increase to 150-200. This is a first order pacemaker. The atrioventricular junction (AV junction), which includes the AV node and the initial part of the His bundle, produces 40-60 electrical impulses per minute. This is a second-order pacemaker. Finally, the lower portion of the His bundle produces only 25-40 impulses per minute. This is a third-order pacemaker.

It should be noted that automatic AV connection and the His bundle is suppressed by the SA node and appears only with lesions of this node. In the normal state of the SA node, pacemakers of the second and third order perform only the conductivity function.

Speed conducting an electrical impulse in different parts of the conduction system is not the same. The minimum conduction velocity is observed in the AV node (50-200 mm/s). In Purkinje fibers, located directly in the ventricular myocardium, the speed of electrical impulses reaches 4000 mm/s.

In this feature prophetic system has an important physiological meaning. Inhibition of conduction in the AV node and high conduction velocity in the ventricular myocardium ensures rapid contraction of the ventricles only after the contraction (expulsion of blood) of the atria has ended. Inhibition of conduction in the AV node also helps to block frequent impulses emanating from the SA node during its pathology.

Electrocardiogram of a healthy person

In a typical electrocardiogram Usually there are several teeth located in different positions relative to the zero line (isoelectric line). Their location relative to the isoelectric line depends on the lead in which the electrocardiogram is recorded. In the standard, most augmented, and lateral thoracic (V5-V6) leads, the P, R, and T waves are positive, and the Q and S waves are negative. The isoelectric line (isoline) corresponds to the level of the T - P segment (from the end of the T wave to the beginning of the P wave) and is fixed on the ECG curve during the absence of potential difference, which occurs during “electrical diastole”.

P wave is a reflection of depolarization (excitation) of the atria, the P-Q interval corresponds to the duration of atrioventricular conduction, and the QRST complex reflects the dynamics of depolarization in the ventricular myocardium. It is believed that the QRS complex reflects the spread of depolarization processes in the ventricular myocardium, and the RS-T segment and the T wave reflect their extinction. The Q wave reflects depolarization processes in the interventricular septum. Point J reflects the beginning of the S-T segment. By its deviation from the isoline, the magnitude of the displacement of the S-T segment is usually judged.

Amplitude and the duration of the ECG waves and segments are normally shown in the figure.

When describing individual ECGs syndromes, we will dwell in more detail on the characteristics of these fragments of the electrocardiogram.

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Cardiogram of a healthy person's heart

A cardiogram of a healthy person shows the contractility of our heart. How to decipher a cardiogram? In this article we will try to give you an accelerated learning of the material. In general, cardiograms can characterize the heart rate, the functional state of the myocardium, and the state of the heart as a whole.

How to understand that a cardiogram is without pathology?

The cardiogram of the heart of a healthy person is characterized by the following.

In leads I, II, aVF, V2-V6, the P wave should always be positive. In lead aVR, on the contrary, it is always negative, as is the T wave in the same lead.
• In leads V1-V4, the amplitude of the R wave increases. V5-V6 - decreases.
• In leads V1-V6, the S wave decreases until it is completely absent.
• The RS-T segment must be on the isoline. An error of 0.5mm is allowed.

These are not all normal ECG indicators. We suggest that you first look at the general scheme for deciphering an ECG and then look at examples of different diseases, because without practice you can’t get anywhere.

General scheme for decoding an ECG:

What do diseases look like on cardiograms?

Conclusion on the first ECG:

1. Atrial flutter with rhythmic ventricular contraction 2:1.
2. Voltage reduced.
3. Normal position of the heart axis.
4. Signs left ventricular hypertrophy .

Conclusion on the second ECG:

1. Sinus rhythm, incomplete atrioventricular block 2 degrees with Samoilov-Wenckebach periods.
2. The voltage is satisfactory.
3. Deviation of the heart axis to the left.
4. Scar changes in the myocardium back wall.

Conclusion on the third ECG:

1. Sinus rhythm. Double-beam blockade of the left branches of the His bundle. 2. Voltage is satisfactory. 3. Deviation of the heart axis to the left.

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

The result of taking electrical indicators, the work of various parts of the organ, is the creation of an electrocardiogram.

Its parameters are recorded on special roll paper. The paper moving speed is available in 3 options:

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

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

Decoding of the recorded electrocardiogram.

The result of the analysis of electrocardiogram parameters is given by a cardiologist. The recording is deciphered by the doctor by establishing the duration of the intervals between the various elements of the recorded indicators. An explanation of the features of the electrocardiogram contains many points:

Normal ECG readings.

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

Electrocardiogram in case of myocardial infarction.

Myocardial infarction occurs due to exacerbation of coronary artery disease, when the internal cavity of the coronary artery of the heart muscle narrows significantly. If this disorder is not corrected within 15 to 20 minutes, the death of the heart muscle cells that receive oxygen and nutrients from this artery occurs. This circumstance creates significant disturbances in the functioning of the heart and turns out to be a severe and serious threat to life. If a heart attack occurs, an electrocardiogram will help identify the location of necrosis. The indicated cardiogram contains noticeably manifested deviations in the electrical signals of the heart muscle:

Heart rhythm disorder.

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

Hypertrophy of the heart.

An increase in the volume of the heart muscles is an adaptation of the organ to new operating conditions. Changes appearing on the electrocardiogram are determined by high bioelectric strength, a characteristic muscle area, a delay in the movement of bioelectric impulses in its thickness, and the appearance of signs of oxygen starvation.

Conclusion.

Electrocardiographic indicators of heart pathology are varied. Reading them is a complex activity that requires special training and improvement of practical skills. A specialist characterizing an ECG needs to know the basic principles of cardiac physiology and various versions of cardiograms. He needs to have skills in identifying abnormalities in cardiac activity. Calculate the effect of medications and other factors on the occurrence of differences in the structure of ECG waves and intervals. Therefore, the interpretation of the electrocardiogram should be entrusted to a specialist who has encountered in his practice various types of deficiencies in the functioning of the heart.

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Before moving on to deciphering the ECG, you need to understand what elements it consists of.

Waves and intervals on the ECG.
It is curious that abroad the P-Q interval is usually called P-R.

Any ECG consists of teeth, segments And intervals.

TEETH- these are convexities and concavities on the electrocardiogram.
The following waves are distinguished on the ECG:

• P(atrial contraction)
• Q, R, S(all 3 teeth characterize contraction of the ventricles),
• T(ventricle relaxation)
• U(non-permanent tooth, rarely recorded).

SEGMENTS
A segment on an ECG is called straight line segment(isolines) between two adjacent teeth. The most important segments are P-Q and S-T. For example, the P-Q segment is formed due to a delay in the conduction of excitation in the atrioventricular (AV-) node.

INTERVALS
The interval consists of tooth (complex of teeth) and segment. Thus, interval = tooth + segment. The most important are the P-Q and Q-T intervals.

Waves, segments and intervals on the ECG.
Pay attention to large and small cells (more about them below).

QRS complex waves

Since the ventricular myocardium is more massive than the atrial myocardium and has not only walls, but also a massive interventricular septum, the spread of excitation in it is characterized by the appearance of a complex complex QRS on the ECG. How to do it right highlight the teeth in it?

First of all they evaluate amplitude (sizes) of individual teeth QRS complex. If the amplitude exceeds 5 mm, the tooth indicates capital letter Q, R or S; if the amplitude is less than 5 mm, then lowercase (small): q, r or s.

The R wave (r) is called any positive(upward) wave that is part of the QRS complex. If there are several teeth, subsequent teeth indicate strokes: R, R", R", etc. Negative (downward) wave of the QRS complex, located before the R wave, is denoted as Q(q), and after - as S(s). If there are no positive waves at all in the QRS complex, then the ventricular complex is designated as QS.

Variants of the QRS complex.

Normal tooth Q reflects depolarization of the interventricular septum, tooth R- the bulk of the ventricular myocardium, tooth S- basal (i.e. near the atria) sections of the interventricular septum. The R V1, V2 wave reflects the excitation of the interventricular septum, and R V4, V5, V6 - the excitation of the muscles of the left and right ventricles. Necrosis of areas of the myocardium (for example, during myocardial infarction) causes the Q wave to widen and deepen, so close attention is always paid to this wave.

ECG analysis

General ECG decoding diagram

1. Checking the correctness of ECG registration.
2. Heart rate and conduction analysis:
   • assessment of heart rate regularity,
   • heart rate (HR) counting,
   • determination of the source of excitation,
   • conductivity assessment.
3. Determination of the electrical axis of the heart.
4. Analysis of the atrial P wave and P-Q interval.
5. Analysis of the ventricular QRST complex:
   • QRS complex analysis,
   • analysis of the RS - T segment,
   • T wave analysis,
   • Q-T interval analysis.
6. Electrocardiographic report.

Normal electrocardiogram.

1) Checking the correct ECG registration

At the beginning of each ECG tape there must be calibration signal- so-called reference millivolt. To do this, at the beginning of the recording, a standard voltage of 1 millivolt is applied, which should display a deviation of 10 mm. Without a calibration signal, the ECG recording is considered incorrect. Normally, in at least one of the standard or enhanced limb leads, the amplitude should exceed 5 mm, and in the chest leads - 8 mm. If the amplitude is lower, it is called reduced ECG voltage, which occurs in some pathological conditions.

Reference millivolt on the ECG (at the beginning of the recording).

2) Heart rate and conduction analysis:

1. assessment of heart rate regularity

   Rhythm regularity is assessed by R-R intervals. If the teeth are at an equal distance from each other, the rhythm is called regular, or correct. The variation in the duration of individual R-R intervals is allowed no more than ± 10% from their average duration. If the rhythm is sinus, it is usually regular.

2. heart rate counting(heart rate)

   The ECG film has large squares printed on it, each of which contains 25 small squares (5 vertical x 5 horizontal). To quickly calculate heart rate with the correct rhythm, count the number of large squares between two adjacent teeth R - R.

   At belt speed 50 mm/s: HR = 600 / (number of large squares).
   At belt speed 25 mm/s: HR = 300 / (number of large squares).

   On the overlying ECG, the R-R interval is approximately 4.8 large cells, which at a speed of 25 mm/s gives 300 / 4.8 = 62.5 beats/min.

   At a speed of 25 mm/s each small cell equal to 0.04 s, and at a speed of 50 mm/s - 0.02 s. This is used to determine the duration of the teeth and intervals.

   If the rhythm is incorrect, it is usually considered maximum and minimum heart rate according to the duration of the smallest and largest R-R interval, respectively.

3. determination of the excitation source

Sinus rhythm(this is a normal rhythm, and all other rhythms are pathological).
The source of excitation is in sinoatrial node. Signs on the ECG:

• in standard lead II, the P waves are always positive and are located before each QRS complex,
• P waves in the same lead have the same shape at all times.

P wave in sinus rhythm.

ATRIAL rhythm. If the source of excitation is located in the lower parts of the atria, then the excitation wave propagates to the atria from bottom to top (retrograde), therefore:

• in leads II and III the P waves are negative,
• There are P waves before each QRS complex.

P wave during atrial rhythm.

Rhythms from the AV connection. If the pacemaker is in the atrioventricular ( atrioventricular node) node, then the ventricles are excited as usual (from top to bottom), and the atria - retrograde (i.e. from bottom to top). At the same time, on the ECG:

• P waves may be absent because they are superimposed on normal QRS complexes,
• P waves can be negative, located after the QRS complex.

Rhythm from the AV junction, superimposition of the P wave on the QRS complex.

Rhythm from the AV junction, the P wave is located after the QRS complex.

Heart rate with a rhythm from the AV junction is less than sinus rhythm and is approximately 40-60 beats per minute.

Ventricular, or IDIOVENTRICULAR, rhythm(from Latin ventriculus [ventrikulyus] - ventricle). In this case, the source of rhythm is the ventricular conduction system. Excitation spreads through the ventricles in the wrong way and is therefore slower. Features of idioventricular rhythm:

• QRS complexes are widened and deformed (they look “scary”). Normally, the duration of the QRS complex is 0.06-0.10 s, therefore, with this rhythm, the QRS exceeds 0.12 s.
• There is no pattern between QRS complexes and P waves because the AV junction does not release impulses from the ventricles, and the atria can be excited from the sinus node, as normal.
• Heart rate less than 40 beats per minute.

Idioventricular rhythm. The P wave is not associated with the QRS complex.

1. conductivity assessment.
   To properly account for conductivity, the recording speed is taken into account.

   To assess conductivity, measure:

   • duration P wave(reflects the speed of impulse transmission through the atria), normally up to 0.1 s.
   • duration interval P - Q(reflects the speed of impulse conduction from the atria to the ventricular myocardium); interval P - Q = (wave P) + (segment P - Q). Fine 0.12-0.2 s.
   • duration QRS complex(reflects the spread of excitation through the ventricles). Fine 0.06-0.1 s.
   • internal deviation interval in leads V1 and V6. This is the time between the beginning of the QRS complex and the R wave. Normal in V1 up to 0.03 s and in V6 up to 0.05 s. It is used mainly to recognize bundle branch blocks and to determine the source of excitation in the ventricles in the case of ventricular extrasystole (extraordinary contraction of the heart).

Measuring the internal deviation interval.

3) Determination of the electrical axis of the heart.
In the first part of the ECG series, it was explained what the electrical axis of the heart is and how it is determined in the frontal plane.

4) Atrial P wave analysis.
Normally, in leads I, II, aVF, V2 - V6, the P wave always positive. In leads III, aVL, V1, the P wave can be positive or biphasic (part of the wave is positive, part is negative). In lead aVR, the P wave is always negative.

Normally, the duration of the P wave does not exceed 0.1 s, and its amplitude is 1.5 - 2.5 mm.

Pathological deviations of the P wave:

• Pointed high P waves of normal duration in leads II, III, aVF are characteristic of right atrial hypertrophy, for example, with “pulmonary heart”.
• Split with 2 apexes, widened P wave in leads I, aVL, V5, V6 is characteristic of left atrial hypertrophy, for example, with mitral valve defects.

Formation of the P wave (P-pulmonale) with hypertrophy of the right atrium.

Formation of the P wave (P-mitrale) with hypertrophy of the left atrium.

P-Q interval: fine 0.12-0.20 s.
An increase in this interval occurs when the conduction of impulses through the atrioventricular node is impaired ( atrioventricular block, AV block).

AV block There are 3 degrees:

• I degree - the P-Q interval is increased, but each P wave has its own QRS complex ( no loss of complexes).
• II degree - QRS complexes partially fall out, i.e. Not all P waves have their own QRS complex.
• III degree - complete blockade of conduction in the AV node. The atria and ventricles contract at their own rhythm, independently of each other. Those. idioventricular rhythm occurs.

5) Ventricular QRST analysis:

1. QRS complex analysis.

   The maximum duration of the ventricular complex is 0.07-0.09 s(up to 0.10 s). The duration increases with any bundle branch block.

   Normally, the Q wave can be recorded in all standard and enhanced limb leads, as well as in V4-V6. The amplitude of the Q wave normally does not exceed 1/4 R wave height, and the duration is 0.03 s. In lead aVR, there is normally a deep and wide Q wave and even a QS complex.

   The R wave, like the Q wave, can be recorded in all standard and enhanced limb leads. From V1 to V4, the amplitude increases (in this case, the r wave of V1 may be absent), and then decreases in V5 and V6.

   The S wave can have very different amplitudes, but usually no more than 20 mm. The S wave decreases from V1 to V4, and may even be absent in V5-V6. In lead V3 (or between V2 - V4) " transition zone"(equality of R and S waves).

2. RS - T segment analysis

   The S-T segment (RS-T) is a segment from the end of the QRS complex to the beginning of the T wave. The S-T segment is especially carefully analyzed in case of coronary artery disease, since it reflects the lack of oxygen (ischemia) in the myocardium.

   Normally, the S-T segment is located in the limb leads on the isoline ( ± 0.5 mm). In leads V1-V3, the S-T segment may shift upward (no more than 2 mm), and in leads V4-V6 - downward (no more than 0.5 mm).

   The point at which the QRS complex transitions to the S-T segment is called the point j(from the word junction - connection). The degree of deviation of point j from the isoline is used, for example, to diagnose myocardial ischemia.

3. T wave analysis.

   The T wave reflects the process of repolarization of the ventricular myocardium. In most leads where a high R is recorded, the T wave is also positive. Normally, the T wave is always positive in I, II, aVF, V2-V6, with T I > T III, and T V6 > T V1. In aVR the T wave is always negative.

4. Q-T interval analysis.

   The Q-T interval is called electrical ventricular systole, because at this time all parts of the ventricles of the heart are excited. Sometimes after the T wave there is a small U wave, which is formed due to short-term increased excitability of the ventricular myocardium after their repolarization.

6) Electrocardiographic report.
Should include:

1. Source of rhythm (sinus or not).
2. Regularity of rhythm (correct or not). Usually sinus rhythm is normal, although respiratory arrhythmia is possible.
3. Position of the electrical axis of the heart.
4. Presence of 4 syndromes:
   • rhythm disturbance
   • conduction disturbance
   • hypertrophy and/or overload of the ventricles and atria
   • myocardial damage (ischemia, dystrophy, necrosis, scars)

Examples of conclusions(not quite complete, but real):

Sinus rhythm with heart rate 65. Normal position of the electrical axis of the heart. No pathology was detected.

Sinus tachycardia with heart rate 100. Single supraventricular extrasystole.

Sinus rhythm with heart rate 70 beats/min. Incomplete blockade of the right bundle branch. Moderate metabolic changes in the myocardium.

Examples of ECG for specific diseases of the cardiovascular system - next time.

ECG interference

Due to frequent questions in the comments about the type of ECG, I’ll tell you about interference which may appear on the electrocardiogram:

Three types of ECG interference(explained below).

Interference on an ECG in the lexicon of health workers is called tip-off:
a) inrush currents: network pickup in the form of regular oscillations with a frequency of 50 Hz, corresponding to the frequency of alternating electric current in the outlet.
b) " swimming"(drift) of the isoline due to poor contact of the electrode with the skin;
c) interference caused by muscle tremors(irregular frequent vibrations are visible).

comment 73 to the note “Electrocardiogram (ECG of the heart). Part 2 of 3: ECG interpretation plan"

thank you very much, it helps to refresh your knowledge, ❗ ❗

My QRS is 104 ms. What does this mean. And is this bad?

The QRS complex is a ventricular complex that reflects the time of propagation of excitation through the ventricles of the heart. Normally in adults it is up to 0.1 seconds. Thus, you are at the upper limit of normal.

If the T wave is positive in the aVR lead, then the electrodes are not applied correctly.

I am 22 years old, I did an ECG, the conclusion says: “Ectopic rhythm, normal direction ... (incomprehensibly written) cardiac axis...”. The doctor said that this happens at my age. What is this and what is it connected with?

“Ectopic rhythm” means a rhythm NOT from the sinus node, which is the source of excitation of the heart normally.

Perhaps the doctor meant that such a rhythm is congenital, especially if there are no other heart diseases. Most likely, the pathways of the heart have not formed entirely correctly.

I can’t say in more detail - you need to know where exactly the source of the rhythm is.

I am 27 years old, the conclusion says: “changes in repolarization processes.” What does it mean?

This means that the recovery phase of the ventricular myocardium after excitation is somehow disrupted. On the ECG it corresponds to the S-T segment and the T wave.

Is it possible to use 8 leads for an ECG instead of 12? 6 chest and I and II leads? And where can I find information about this?

Maybe. It all depends on the purpose of the survey. Some rhythm disturbances can be diagnosed by one (any) lead. In case of myocardial ischemia, all 12 leads must be taken into account. If necessary, additional leads are removed. Read books on ECG analysis.

What will aneurysms look like on an ECG? And how to identify them? Thank you in advance…

Aneurysms are pathological dilations of blood vessels. They cannot be detected on an ECG. Aneurysms are diagnosed using ultrasound and angiography.

Please explain what “ …Sinus. rhythm 100/min.". Is this good or bad?

“Sinus rhythm” means that the source of electrical impulses in the heart is in the sinus node. This is the norm.

“100 per minute” is the heart rate. Normally, in adults it is from 60 to 90, in children it is higher. That is, in this case the frequency is slightly increased.

The cardiogram indicated: sinus rhythm, nonspecific ST-T changes, possibly electrolyte changes. The therapist said it didn't mean anything, did it?

Nonspecific are changes that occur in various diseases. In this case, there are slight changes on the ECG, but it is impossible to really understand what their cause is.

Electrolyte changes are changes in the concentrations of positive and negative ions (potassium, sodium, chlorine, etc.)

Does the fact that the child did not lie still and laugh during the recording affect the ECG results?

If the child behaved restlessly, then the ECG may show interference caused by electrical impulses from the skeletal muscles. The ECG itself will not change, it will just be more difficult to decipher.

What does the ECG conclusion mean - SP 45% N?

Most likely, what is meant is the “systolic indicator”. What is meant by this concept is not clearly explained on the Internet. Possibly the ratio of the duration of the Q-T interval to the R-R interval.

In general, the systolic indicator or systolic index is the ratio of minute volume to the patient’s body area. Only I have not heard of this function being determined by ECG. It is better for patients to focus on the letter N, which means normal.

The ECG shows a biphasic R wave. Is it considered pathological?

It's impossible to say. The type and width of the QRS complex in all leads is assessed. Particular attention is paid to the Q (q) waves and their proportions with R.

Jaggedness of the descending limb of the R wave, in I AVL V5-V6, occurs in anterolateral MI, but it makes no sense to consider this sign in isolation without others, there will still be changes in the ST interval with discrepancy, or the T wave.

Occasionally the R wave falls out (disappears). What does it mean?

If these are not extrasystoles, then the variations are most likely caused by different conditions for conducting impulses.

Now I’m sitting and re-analyzing the ECG, my head is a complete mess, what the teacher explained. What is the most important thing you need to know so as not to get confused?((((

I can do this. We have recently started the subject of syndromic pathology, and they are already giving patients ECGs and we must immediately say what is on the ECG, and here the confusion begins.

Julia, you want to immediately be able to do what specialists learn throughout their lives. 🙂

Buy and study several serious books on ECG, watch various cardiograms more often. When you learn from memory to draw a normal 12-lead ECG and ECG variants for major diseases, you will be able to very quickly determine the pathology on film. However, you will have to work hard.

An unspecified diagnosis is written separately on the ECG. What does it mean?

This is definitely not the conclusion of an electrocardiogram. Most likely, the diagnosis was implied when referring for an ECG.

thank you for the article, it really helps to understand the initial stages and Murashko is then easier to perceive)

What does QRST = 0.32 mean as a result of an electrocardiogram? Is this some kind of violation? With what it can be connected?

Length of the QRST complex in seconds. This is a normal indicator, do not confuse it with the QRS complex.

I found the results of an ECG from 2 years ago, in the conclusion it says “ signs of left ventricular myocardial hypertrophy". After this, I did an ECG 3 more times, the last time 2 weeks ago, in all three last ECGs in the conclusion there was not a word about LV myocardial hypertrophy. With what it can be connected?

Most likely, in the first case, the conclusion was made tentatively, that is, without compelling reasons: “ signs of hypertrophy..." If there were clear signs on the ECG it would indicate “ hypertrophy…».

how to determine the amplitude of the teeth?

The amplitude of the teeth is calculated by millimeter divisions of the film. At the beginning of each ECG there should be a control millivolt equal to 10 mm in height. The amplitude of the teeth is measured in millimeters and varies.

Normally, in at least one of the first 6 leads, the amplitude of the QRS complex is at least 5 mm, but not more than 22 mm, and in the chest leads - 8 mm and 25 mm, respectively. If the amplitude is smaller, they speak of reduced voltage ECG. True, this term is conditional, since, according to Orlov, there are no clear distinction criteria for people with different body types.

In practice, the ratio of individual teeth in the QRS complex, especially Q and R, is more important, because this may be a sign of myocardial infarction.

I am 21 years old, the conclusion says: sinus tachycardia with heart rate 100. Moderate diffusion in the myocardium of the left ventricle. What does it mean? Is it dangerous?

Increased heart rate (normally 60-90). “Moderate diffuse changes” in the myocardium - a change in electrical processes throughout the myocardium due to its dystrophy (impaired cell nutrition).

The cardiogram is not fatal, but it cannot be called good either. You need to be examined by a cardiologist to find out what is happening to the heart and what can be done.

My report says “sinus arrhythmia,” although the therapist said that the rhythm is correct, and visually the teeth are located at the same distance. How can this be?

The conclusion is made by a person, so it can be somewhat subjective (this applies to both the therapist and the functional diagnostics doctor). As written in the article, with correct sinus rhythm “ a spread in the duration of individual R-R intervals is allowed no more than ± 10% of their average duration." This is due to the presence respiratory arrhythmia, about which is written in more detail here:
website/info/461

What can left ventricular hypertrophy lead to?

I am 35 years old. In conclusion it is written: “ the R wave grows weakly in V1-V3". What does it mean?

Tamara, with hypertrophy of the left ventricle, thickening of its wall occurs, as well as remodeling (rebuilding) of the heart - a violation of the correct relationship between muscle and connective tissue. This leads to an increased risk of myocardial ischemia, congestive heart failure and arrhythmias. More details: plaintest.com/beta-blockers

Anna, in the chest leads (V1-V6), the amplitude of the R wave should normally increase from V1 to V4 (i.e., each subsequent wave should be greater than the previous one). In V5 and V6 the R wave is usually smaller in amplitude than in V4.

Tell me, what is the reason for the deviation in the EOS to the left and what does this mean? What is a complete right bundle branch block?

Deviation of the EOS (electrical axis of the heart) to the left There is usually hypertrophy of the left ventricle (i.e. thickening of its wall). Sometimes deviation of the EOS to the left occurs in healthy people if their diaphragm dome is located high (hypersthenic physique, obesity, etc.). For correct interpretation, it is advisable to compare the ECG with previous ones.

Complete right bundle branch block- this is a complete cessation of the propagation of electrical impulses along the right bundle branch (see here article on the conduction system of the heart).

hello, what does this mean? left type ecg, IBPBP and BPVPL

Left type of ECG - deviation of the electrical axis of the heart to the left.
IBPBP (more precisely: IBPBP) is an incomplete blockade of the right bundle branch.
LPBL - blockade of the anterior branch of the left bundle branch.

Tell me, please, what does the small growth of the R wave in V1-V3 indicate?

Normally, in leads V1 to V4, the R wave should increase in amplitude, and in each subsequent lead it should be higher than in the previous one. The absence of such an increase or a ventricular complex of the QS type in V1-V2 is a sign of myocardial infarction of the anterior part of the interventricular septum.

You need to redo the ECG and compare it with the previous ones.

Tell me, please, what does it mean “R increases poorly in V1 - V4”?

This means that it is growing either fast enough or not evenly enough. See my previous comment.

Tell me, where can a person who doesn’t understand this in life get an ECG so that they can tell him everything about it in detail later?

I did it six months ago, but I still didn’t understand anything from the vague phrases of the cardiologist. And now my heart began to worry again...

You can consult another cardiologist. Or send me an ECG report, I’ll explain. Although, if six months have passed and something is bothering you, you need to do an ECG again and compare them.

Not all ECG changes clearly indicate certain problems; most often, a change can have a dozen reasons. Such as, for example, changes in the T wave. In these cases, everything must be taken into account - complaints, medical history, results of examinations and medications, the dynamics of ECG changes over time, etc.

My son is 22 years old. His heart rate is from 39 to 149. What could this be? The doctors don't really say anything. Prescribed Concor

During the ECG, breathing should be normal. Additionally, after taking a deep breath and holding your breath, standard lead III is recorded. This is necessary to check for respiratory sinus arrhythmia and ECG positional changes.

If your resting heart rate ranges from 39 to 149, you may have sick sinus syndrome. In SSSS, Concor and other beta blockers are prohibited, since even small doses can cause a significant decrease in heart rate. My son needs to be examined by a cardiologist and have an atropine test done.

At the conclusion of the ECG it is written: metabolic changes. What does it mean? Is it necessary to consult a cardiologist?

Metabolic changes in the ECG conclusion can also be called dystrophic (electrolyte) changes, as well as a violation of repolarization processes (the last name is the most correct). They imply a metabolic disorder in the myocardium that is not associated with an acute disturbance of the blood supply (i.e., with a heart attack or progressive angina). These changes usually affect the T wave (it changes its shape and size) in one or more areas, lasting for years without the dynamics characteristic of a heart attack. They do not pose a danger to life. It is impossible to say the exact reason by ECG, because these nonspecific changes occur in a variety of diseases: hormonal disorders (especially menopause), anemia, cardiac dystrophy of various origins, ion balance disorders, poisoning, liver disease, kidney disease, inflammatory processes, heart injuries, etc. But you need to go to a cardiologist to try to figure out what is the reason for the changes on the ECG.

The conclusion of the ECG says: insufficient increase in R in the chest leads. What does it mean?

This can be either a normal variant or a possible myocardial infarction. The cardiologist needs to compare the ECG with previous ones, taking into account the complaints and clinical picture, if necessary, prescribe an EchoCG, a blood test for markers of myocardial damage, and repeat the ECG.

1. hello, tell me, under what conditions and in which leads will a positive Q wave be observed?

   There is no such thing as a positive Q wave (q), it is either there or it is not. If this tooth is directed upward, it is called R (r).

2. Question about heart rate. I bought a heart rate monitor. I used to work without it. I was surprised when the maximum heart rate was 228. There were no unpleasant sensations. I never complained about my heart. 27 years. Bike. In a calm state, the pulse is about 70. I checked the pulse manually without loads, the readings are correct. Is this normal or should the load be limited?

   The maximum heart rate during physical activity is calculated as “220 minus age.” For you, 220 - 27 = 193. Exceeding it is dangerous and undesirable, especially for a person with little training and for a long time. It is better to exercise less intensely, but for longer. Aerobic load threshold: 70-80% of maximum heart rate (135-154 for you). There is an anaerobic threshold: 80-90% of maximum heart rate.

   Since on average 1 inhalation-exhalation corresponds to 4 heartbeats, you can simply focus on the breathing frequency. If you can not only breathe, but also speak short phrases, then it’s fine.

3. Please explain what parasystole is and how it is detected on an ecg.

   Parasystole is the parallel functioning of two or more pacemakers in the heart. One of them is usually the sinus node, and the second (ectopic pacemaker) is most often located in one of the ventricles of the heart and causes contractions called parasystoles. To diagnose parasystole, a long-term ECG recording is required (one lead is sufficient). Read more in V.N. Orlov’s “Guide to Electrocardiography” or in other sources.

   Signs of ventricular parasystole on the ECG:
   1) parasystoles are similar to ventricular extrasystoles, but the coupling interval is different, because there is no connection between sinus rhythm and parasystoles;
   2) there is no compensatory pause;
   3) the distances between individual parasystoles are multiples of the smallest distance between parasystoles;
   4) a characteristic sign of parasystole is confluent contractions of the ventricles, in which the ventricles are excited from 2 sources simultaneously. The shape of the confluent ventricular complexes is intermediate between sinus contractions and parasystoles.

4. Hello, please tell me what a small increase in R means on the ECG transcript.

   This is simply a statement of the fact that in the chest leads (from V1 to V6) the amplitude of the R wave does not increase quickly enough. The reasons can be very different; they are not always easy to determine using an ECG. Comparison with previous ECGs, dynamic observation and additional examinations help.

5. Tell me what could be causing the change in QRS, which ranges from 0.094 s to 0.132 on different ECGs?

   A transient (temporary) disturbance of intraventricular conduction is possible.

6. Thank you for including the tips at the end. And then I received an ECG without decoding and when I saw solid waves on V1, V2, V3 as in example (a) - I felt uneasy...

7. Please tell me what do biphasic P waves in I, v5, v6 mean?

   A wide double-humped P wave is usually recorded in leads I, II, aVL, V5, V6 with hypertrophy of the left atrium.

8. Please tell me what the ECG conclusion means: “ Noteworthy is the Q wave in III, AVF (leveled off on inspiration), probably features of intraventricular conduction of a positional nature.»?

   Leveling = disappearing.

   The Q wave in leads III and aVF is considered pathological if it exceeds 1/2 of the R wave and is wider than 0.03 s. In the presence of pathological Q(III) only in the III standard lead, a test with a deep breath helps: with a deep breath, the Q associated with myocardial infarction is preserved, while the positional Q(III) decreases or disappears.

   Since it is not constant, it is assumed that its appearance and disappearance is not associated with a heart attack, but with the position of the heart.

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

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

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

Operating principle

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

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

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

When and why is it carried out?

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

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

Conclusion The ECG also reveals dilatation of the heart in case of heart failure or pulmonary embolism. A cardiogram is usually performed as part of a preoperative examination before a planned procedure under general anesthesia, or as part of a general examination.

There is no need to follow any special regime before the examination. All that matters is calmness.

Carrying out an examination

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

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

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

ECG modification

There are several ways to measure basic heart indicators:

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

24-hour Holter ECG monitoring

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

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

This test is also used primarily in adults for symptoms that occur less frequently. The person wears the device for longer than a day or two, activating it when difficulties arise.

Load monitoring

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

Esophageal monitoring

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

Decoding the curve

Decoding the cardiogram consists of 10 points:

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

The following table provides the norm indicators:

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

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

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

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

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

P wave

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

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

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

PQ interval

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

Pathology:

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

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

QRS complex

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

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

The QRS complex evaluates 3 factors:

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

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

QRS indicators:

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

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

Sokolov indices (Sokolov-Lyon criteria for ventricular hypertrophy)

From the size of the amplitude of QRS oscillations, the thickness of the chamber wall can be approximately determined. For this purpose, Sokolov indices are used, 1 for the right and 2 for the left ventricle.

Indicators for the right ventricle:

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

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

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

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

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

T wave

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

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

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

Deviations of the T wave occur during myocardial hypoxia.

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

QT interval

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

Research results

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

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

Quick page navigation

Almost every person who has undergone an electrocardiogram is interested in the meaning of different teeth and the terms written by the diagnostician. Although only a cardiologist can give a full interpretation of an ECG, everyone can easily figure out whether their heart cardiogram is good or if there are some abnormalities.

Indications for an ECG

A non-invasive study - an electrocardiogram - is performed in the following cases:

• The patient complains of high blood pressure, chest pain and other symptoms indicating cardiac pathology;
• Deterioration in the well-being of a patient with a previously diagnosed cardiovascular disease;
• Abnormalities in laboratory blood tests - increased cholesterol, prothrombin;
• In preparation for surgery;
• Detection of endocrine pathology, diseases of the nervous system;
• After severe infections with a high risk of heart complications;
• For prophylactic purposes in pregnant women;
• Examination of the health status of drivers, pilots, etc.

Decoding ECG - numbers and Latin letters

A full-scale interpretation of the cardiac cardiogram includes an assessment of the heart rhythm, the functioning of the conduction system and the condition of the myocardium. For this, the following leads are used (electrodes are installed in a certain order on the chest and limbs):

• Standard: I - left/right wrist on the hands, II - right wrist and ankle area on the left leg, III - left ankle and wrist.
• Strengthened: aVR - right wrist and combined left upper/lower limbs, aVL - left wrist and combined left ankle and right wrist, aVF - left ankle area and combined potential of both wrists.
• Thoracic (potential difference between the electrode with a suction cup located on the chest and the combined potentials of all extremities): V1 - electrode in the IV intercostal space along the right border of the sternum, V2 - in the IV intercostal space to the left of the sternum, V3 - on the IV rib along the left-sided parasternal line, V4 - V intercostal space along the left midclavicular line, V5 - V intercostal space along the anterior axillary line on the left, V6 - V intercostal space along the mid-axillary line on the left.

Additional pectorals - located symmetrically to the left pectoralis with additional V7-9.

One cardiac cycle on the ECG is represented by the PQRST graph, which records electrical impulses in the heart:

• P wave - displays atrial excitation;
• QRS complex: Q wave - the initial phase of depolarization (excitation) of the ventricles, R wave - the actual process of ventricular excitation, S wave - the end of the depolarization process;
• T wave - characterizes the extinction of electrical impulses in the ventricles;
• ST segment - describes the complete restoration of the original state of the myocardium.

When deciphering ECG indicators, the height of the teeth and their location relative to the isoline, as well as the width of the intervals between them, are important.

Sometimes a U pulse is recorded behind the T wave, indicating the parameters of the electrical charge carried away with the blood.

Interpretation of ECG indicators - the norm in adults

On the electrocardiogram, the width (horizontal distance) of the teeth - the duration of the period of excitation of relaxation - is measured in seconds, the height in leads I-III - the amplitude of the electrical impulse - in mm. A normal cardiogram in an adult looks like this:

• Heart rate - normal heart rate is within 60-100/min. The distance from the tops of adjacent R waves is measured.
• EOS - the electrical axis of the heart is considered to be the direction of the total angle of the electrical force vector. The normal value is 40-70º. Deviations indicate rotation of the heart around its own axis.
• The P wave is positive (directed upward), negative only in lead aVR. Width (duration of excitation) - 0.7 - 0.11 s, vertical size - 0.5 - 2.0 mm.
• PQ interval - horizontal distance 0.12 - 0.20 s.
• The Q wave is negative (below the isoline). Duration 0.03 s, negative height value 0.36 - 0.61 mm (equal to ¼ of the vertical size of the R wave).
• The R wave is positive. What matters is its height - 5.5 -11.5 mm.
• S wave - negative height 1.5-1.7 mm.
• QRS complex - horizontal distance 0.6 - 0.12 s, total amplitude 0 - 3 mm.
• The T wave is asymmetrical. Positive height 1.2 - 3.0 mm (equal to 1/8 - 2/3 of the R wave, negative in the aVR lead), duration 0.12 - 0.18 s (longer than the duration of the QRS complex).
• ST segment - passes at the level of the isoline, length 0.5 -1.0 s.
• U wave - height indicator 2.5 mm, duration 0.25 s.

Abbreviated results of ECG interpretation in adults and the norm in the table:

During normal research (recording speed - 50 mm/sec), ECG decoding in adults is carried out according to the following calculations: 1 mm on paper when calculating the duration of intervals corresponds to 0.02 sec.

A positive P wave (standard leads) followed by a normal QRS complex means normal sinus rhythm.

Normal ECG in children, interpretation

Cardiogram parameters in children are somewhat different from those in adults and vary depending on age. Interpretation of the ECG of the heart in children, normal:

• Heart rate: newborns - 140 - 160, by 1 year - 120 - 125, by 3 years - 105 -110, by 10 years - 80 - 85, after 12 years - 70 - 75 per minute;
• EOS - corresponds to adult indicators;
• sinus rhythm;
• tooth P - does not exceed 0.1 mm in height;
• length of the QRS complex (often not particularly informative in diagnosis) - 0.6 - 0.1 s;
• PQ interval - less than or equal to 0.2 s;
• Q wave - unstable parameters, negative values ​​in lead III are acceptable;
• P wave - always above the isoline (positive), the height in one lead may fluctuate;
• S wave - negative indicators of variable value;
• QT - no more than 0.4 s;
• The duration of the QRS and the T wave are equal, 0.35 - 0.40.

Example of an ECG with rhythm disturbance

Based on deviations in the cardiogram, a qualified cardiologist can not only diagnose the nature of the heart disease, but also record the location of the pathological focus.

Arrhythmias

The following cardiac rhythm disorders are distinguished:

1. Sinus arrhythmia - the length of the RR intervals fluctuates with a difference of up to 10%. It is not considered a pathology in children and young people.
2. Sinus bradycardia is a pathological decrease in the frequency of contractions to 60 per minute or less. The P wave is normal, PQ from 12 s.
3. Tachycardia - heart rate 100 - 180 per minute. In teenagers - up to 200 per minute. The rhythm is correct. With sinus tachycardia, the P wave is slightly higher than normal, with ventricular tachycardia, the QRS length indicator is above 0.12 s.
4. Extrasystoles are extraordinary contractions of the heart. Single ones on a regular ECG (on a 24-hour Holter - no more than 200 per day) are considered functional and do not require treatment.
5. Paroxysmal tachycardia is a paroxysmal (several minutes or days) increase in heart rate up to 150-220 per minute. It is characteristic (only during an attack) that the P wave merges with the QRS. The distance from the R wave to the P height of the next contraction is less than 0.09 s.
6. Atrial fibrillation is an irregular contraction of the atria with a frequency of 350-700 per minute, and of the ventricles - 100-180 per minute. There is no P wave, there are small-to-large undulating oscillations along the entire isoline.
7. Atrial flutter - up to 250-350 atrial contractions per minute and regular slow ventricular contractions. The rhythm may be correct; the ECG shows sawtooth atrial waves, especially pronounced in standard leads II - III and thoracic leads V1.

Deviation of EOS position

A change in the total EOS vector to the right (more than 90º), a higher value of the height of the S wave compared to the R wave indicate pathology of the right ventricle and His bundle block.

When the EOS is shifted to the left (30-90º) and there is a pathological ratio of the heights of the S and R waves, left ventricular hypertrophy and blockade of the bundle branch of His are diagnosed. Deviation of EOS indicates a heart attack, pulmonary edema, COPD, but it can also be normal.

Violation of the conduction system

The following pathologies are most often recorded:

• 1st degree of atrioventricular (AV) block - PQ distance more than 0.20 s. After each P, QRS naturally follows;
• Atrioventricular block, stage 2. - a gradually lengthening PQ throughout the ECG sometimes displaces the QRS complex (Mobitz 1 type deviation) or a complete loss of QRS is recorded against the background of a PQ of equal length (Mobitz 2);
• Complete block of the AV node - the atrial heart rate is higher than the ventricular heart rate. PP and RR are the same, PQ are different lengths.

Selected heart diseases

The results of ECG interpretation can provide information not only about the heart disease that has occurred, but also about the pathology of other organs:

1. Cardiomyopathy - atrial hypertrophy (usually the left one), low-amplitude waves, partial blockade of the His, atrial fibrillation or extrasystoles.
2. Mitral stenosis - the left atrium and right ventricle are enlarged, the EOS is deviated to the right, often atrial fibrillation.
3. Mitral valve prolapse - flattened/negative T wave, some QT prolongation, depressed ST segment. Various rhythm disturbances are possible.
4. Chronic pulmonary obstruction - EOS is to the right of normal, low-amplitude waves, AV block.
5. Damage to the central nervous system (including subarachnoid hemorrhage) - pathological Q, wide and high-amplitude (negative or positive) T wave, pronounced U, long duration of QT rhythm disturbance.
6. Hypothyroidism - long PQ, low QRS, flat T wave, bradycardia.

Quite often, an ECG is performed to diagnose myocardial infarction. At the same time, each of its stages corresponds to characteristic changes in the cardiogram:

• ischemic stage - a pointed T with a sharp apex is recorded 30 minutes before the onset of necrosis of the heart muscle;
• stage of damage (changes are recorded in the first hours to 3 days) - ST in the form of a dome above the isoline merges with the T wave, shallow Q and high R;
• acute stage (1-3 weeks) - the worst cardiogram of the heart during a heart attack - preservation of the dome-shaped ST and the transition of the T wave to negative values, decreased height of R, pathological Q;
• subacute stage (up to 3 months) - comparison of ST with the isoline, preservation of pathological Q and T;
• stage of scarring (several years) - pathological Q, negative R, smoothed T wave gradually comes to normal values.

There is no need to sound the alarm if you find pathological changes in the ECG issued to you. It should be remembered that some deviations from the norm occur in healthy people.

If an electrocardiogram reveals any pathological processes in the heart, you will definitely be scheduled for a consultation with a qualified cardiologist.