ECG uncertain position of EOS. What does the vertical position of the heart axis on an ECG mean?

In this issue I will briefly touch on these issues. From the next issues we will begin to study pathology.

Also, previous issues and materials for a more in-depth study of ECG can be found in the "" section.

1. What is the resulting vector?

Inextricably linked with the concept of the resulting vector of ventricular excitation in the frontal plane.

The resulting vector of ventricular excitation is the sum of three moment vectors of excitation: the interventricular septum, the apex and base of the heart.
This vector has a certain orientation in space, which we interpret in three planes: frontal, horizontal and sagittal. In each of them, the resulting vector has its own projection.

2. What is the electrical axis of the heart?

Electrical axis of the heart called the projection of the resulting vector of ventricular excitation in the frontal plane.

The electrical axis of the heart may deviate from its normal position either to the left or to the right. The exact deviation of the electrical axis of the heart is determined by the alpha (a) angle.

3. What is the alpha angle?

Let us mentally place the resulting vector of ventricular excitation inside Einthoven’s triangle. Corner, formed by the direction of the resulting vector and the I axis of the standard lead, and is required angle alpha.

The value of the alpha angle are found using special tables or diagrams, having previously determined on the electrocardiogram the algebraic sum of the teeth of the ventricular complex (Q + R + S) in standard leads I and III.

Find the algebraic sum of the teeth ventricular complex is quite simple: measure in millimeters the size of each wave of one ventricular QRS complex, taking into account that the Q and S waves have a minus sign (-), since they are below the isoelectric line, and the R wave has a plus sign (+). If any wave on the electrocardiogram is missing, then its value is equal to zero (0).

If the alpha angle is within 50-70°, talk about the normal position of the electrical axis of the heart (the electrical axis of the heart is not deviated), or a normogram. When the electrical axis of the heart deviates right angle alpha will be determined in within 70-90°. In everyday life, this position of the electrical axis of the heart is called a legal grammar.

If the alpha angle is greater than 90° (for example, 97°), it is considered that this ECG has block of the posterior branch of the left bundle branch.
By defining the alpha angle within 50-0° we speak of deviation of the electrical axis of the heart to the left, or levogram.
A change in the alpha angle within 0 - minus 30° indicates a sharp deviation of the electrical axis of the heart to the left or, in other words, about the sharp leftogram.
And finally, if the value of the alpha angle is less than minus 30° (for example, minus 45°), they speak of anterior branch blockade left bundle branch.

Determination of the deviation of the electrical axis of the heart by the alpha angle using tables and diagrams is carried out mainly by doctors in functional diagnostics offices, where the corresponding tables and diagrams are always at hand.
However, it is possible to determine the deviation of the electrical axis of the heart without the necessary tables.

In this case, the deviation of the electrical axis is determined by analyzing the R and S waves in standard leads I and III. In this case, the concept of the algebraic sum of the teeth of the ventricular complex is replaced by the concept "defining tooth" QRS complex, visually comparing the R and S waves in absolute value. They speak of an “R-type ventricular complex,” meaning that in this ventricular complex the R wave is higher. On the contrary, in "S-type ventricular complex" The defining wave of the QRS complex is the S wave.

If on the electrocardiogram in the first standard lead the ventricular complex is represented by the R-type, and the QRS complex in the third standard lead has an S-type shape, then in in this case electric the axis of the heart is deviated to the left (levogram). Schematically, this condition is written as RI-SIII.

On the contrary, if in standard lead I we have the S-type of the ventricular complex, and in lead III the R-type of the QRS complex, then the electrical axis of the heart deviated to the right (pravogram).
Simplified, this condition is written as SI-RIII.

The resulting vector of ventricular excitation is normally located in frontal plane like this that its direction coincides with the direction of axis II of the standard lead.

The figure shows that the amplitude of the R wave in standard lead II is greatest. In turn, the R wave in standard lead I exceeds the RIII wave. Under this condition of the ratio of R waves in various standard leads, we have normal position of the electrical axis of the heart(the electrical axis of the heart is not deviated). A short notation for this condition is RII>RI>RIII.

4. What is the electrical position of the heart?

Close in meaning to the electrical axis of the heart is the concept electrical position of the heart. Under the electrical position of the heart imply the direction of the resulting vector of ventricular excitation relative to axis I of the standard lead, taking it as if it were the horizon line.

Distinguish vertical position of the result vector relative to axis I of the standard lead, calling it the vertical electrical position of the heart, and the horizontal position of the vector is the horizontal electrical position of the heart.

There is also a basic (intermediate) electrical position of the heart, semi-horizontal and semi-vertical. The figure shows all the positions of the resulting vector and the corresponding electrical positions of the heart.

For these purposes, the ratio of the amplitude of the K waves of the ventricular complex in the unipolar leads aVL and aVF is analyzed, keeping in mind the features of the graphic display of the resulting vector with the recording electrode (Fig. 18-21).

Conclusions from this issue of the newsletter “Learning ECG step by step - it’s easy!”:

1. The electrical axis of the heart is the projection of the resulting vector in the frontal plane.

2. The electrical axis of the heart is capable of deviating from its normal position either to the right or to the left.

3. The deviation of the electrical axis of the heart can be determined by measuring the alpha angle.

A small reminder:

4. The deviation of the electrical axis of the heart can be determined visually.
RI-SШ levogram
RII > RI > RIII normogram
SI-RIII spelling

5. The electrical position of the heart is the position of the resulting vector of excitation of the ventricles in relation to axis I of the standard lead.

6. On the ECG, the electrical position of the heart is determined by the amplitude of the R wave, comparing it in leads aVL and aVF.

7. The following electrical positions of the heart are distinguished:

Conclusion.

You can find everything you need to study deciphering an ECG and determining the electrical axis of the heart in the section of the site: " ". The section contains both clear articles and video tutorials.
If there are problems with understanding or deciphering, we are waiting for questions on the forum for free consultations with a doctor -.

Additional Information:

1. The concept of “inclination of the electrical axis of the heart”

In some cases, when visually determining the position of the electrical axis of the heart, a situation is observed when the axis deviates from its normal position to the left, but clear signs of a leftogram are not detected on the ECG. The electrical axis is, as it were, in a borderline position between the normogram and the levogram. In these cases, they talk about a tendency to levogramma. In a similar situation, deviations of the axis to the right indicate a tendency towards a right-hand grammar.

2. The concept of “uncertain electrical position of the heart”

In some cases, it is not possible to find on the electrocardiogram the conditions described for determining the electrical position of the heart. In this case, they speak of an uncertain position of the heart.

Many researchers believe that the practical significance of the electrical position of the heart is small. It is usually used for more accurate topical diagnosis of the pathological process occurring in the myocardium and to determine hypertrophy of the right or left ventricle.

Training video for determining the EOS (electrical axis of the heart) using an ECG

Electrical axis of the heart - those words that appear first when deciphering an electrocardiogram. When they write that her position is normal, the patient is satisfied and happy. However, in conclusions they often write about the horizontal, vertical axis, and its deviations. In order not to experience unnecessary anxiety, it is worth having an understanding of EOS: what it is, and what the dangers are if its position is different from the normal one.

General idea of ​​EOS - what is it

It is known that the heart, during its tireless work, generates electrical impulses. They originate in a certain area - in the sinus node, then normally the electrical excitation passes to the atria and ventricles, spreading along the conducting nerve bundle, called the bundle of His, along its branches and fibers. In total, this is expressed as an electric vector, which has a direction. EOS is the projection of this vector onto the anterior vertical plane.

Doctors calculate the position of the EOS by plotting the amplitudes of the ECG waves on the axis of the Einthoven triangle formed by standard ECG leads from the limbs:

• the amplitude of the R wave minus the amplitude of the S wave of the first lead is plotted on the L1 axis;
• a similar magnitude of the amplitude of the teeth of the third lead is deposited on the L3 axis;
• from these points, perpendiculars are set towards each other until they intersect;
• the line from the center of the triangle to the intersection point is the graphic expression of the EOS.

Its position is calculated by dividing the circle describing the Einthoven triangle into degrees. Typically, the direction of the EOS roughly reflects the location of the heart in the chest.

The normal position of the EOS - what is it?

Determine the position of the EOS

• speed and quality of passage of the electrical signal through the structural divisions of the conduction system of the heart,
• the ability of the myocardium to contract,
• changes in internal organs that can affect the functioning of the heart, and in particular the conduction system.

In a person who does not have serious health problems, the electrical axis can occupy a normal, intermediate, vertical or horizontal position.

It is considered normal when the EOS is located in the range from 0 to +90 degrees, depending on constitutional features. Most often, normal EOS is located between +30 and +70 degrees. Anatomically, it is directed down and to the left.

The intermediate position is between +15 and +60 degrees.

On the ECG, positive waves are higher in the second, aVL, aVF leads.

• R2>R1>R3 (R2=R1+R3),
• R3>S3,
• R aVL=S aVL.

Vertical position of the EOS

When verticalized, the electrical axis is located between +70 and +90 degrees.

It occurs in people with a narrow chest, tall and thin. Anatomically, the heart literally “hangs” in their chest.

On the ECG, the highest positive waves are recorded in aVF. Deep negative – in aVL.

• R2=R3>R1;
• R1=S1;
• R aVF>R2,3.

Horizontal position of the EOS

The horizontal position of the EOS is between +15 and -30 degrees.

It is typical for healthy people with a hypersthenic physique - wide chest, short stature, increased weight. The heart of such people “lies” on the diaphragm.

On the ECG, the highest positive waves are recorded in aVL, and the deepest negative ones in aVF.

• R1>R2>R3;
• R aVF=S aVF
• R2>S2;
• S3=R3.

Deviation of the electrical axis of the heart to the left - what does it mean?

The deviation of the EOS to the left is its location in the range from 0 to -90 degrees. Up to -30 degrees can still be considered a variant of the norm, but a more significant deviation indicates a serious pathology or a significant change in the location of the heart. for example, during pregnancy. Also observed with maximally deep exhalation.

Pathological conditions accompanied by deviation of the EOS to the left:

• hypertrophy of the left ventricle of the heart is a companion and consequence of prolonged arterial hypertension;
• violation, blockade of conduction along the left leg and fibers of the His bundle;
• left ventricular myocardial infarction;
• heart defects and their consequences that change the conduction system of the heart;
• cardiomyopathy, which impairs the contractility of the heart muscle;
• myocarditis - inflammation also impairs the contractility of muscle structures and the conduction of nerve fibers;
• cardiosclerosis;
• myocardial dystrophy;
• calcium deposits in the heart muscle, preventing it from contracting normally and disrupting innervation.

These and similar diseases and conditions lead to an increase in the cavity or mass of the left ventricle. As a result, the excitation vector travels longer on the left side and the axis deviates to the left.

The ECG in the second and third leads is characterized by deep S waves.

• R1>R2>R2;
• R2>S2;
• S3>R3;
• S aVF>R aVF.

Deviation of the electrical axis of the heart to the right - what does it mean?

Eos is deviated to the right if it is in the range from +90 to +180 degrees.

Possible reasons for this phenomenon:

• violation of the conduction of electrical excitation along the fibers of the His bundle, its right branch;
• myocardial infarction in the right ventricle;
• overload of the right ventricle due to narrowing of the pulmonary artery;
• chronic pulmonary pathology, the consequence of which is “pulmonary heart”, characterized by intense work of the right ventricle;
• the combination of coronary artery disease with hypertension - depletes the heart muscle, leading to heart failure;
• PE - blocking of blood flow in the branches of the pulmonary artery, of thrombotic origin, as a result the blood supply to the lungs is depleted, their vessels spasm, which leads to a load on the right side of the heart;
• mitral heart disease, valve stenosis, causing congestion in the lungs, which causes pulmonary hypertension and increased work of the right ventricle;
• dextrocardia;
• emphysema – moves the diaphragm down.

On the ECG, a deep S wave is noted in the first lead, while in the second and third it is small or absent.

• R3>R2>R1,
• S1>R1.

It should be understood that a change in the position of the heart axis is not a diagnosis, but only signs of conditions and diseases, and only an experienced specialist should understand the reasons.

The figure below shows the six-axis Bailey lead system, which shows the red vector electrical axis of the heart located horizontally (angle α=0..+30°). The dotted line marks the projections of the e.o.s. vector. on the lead axis. Explanations for the figure are given in the table below.

On the "Automatic detection of EOS" page, a specially developed script will help you determine the location of the EOS based on ECG data from any two different leads.

Signs of horizontal position of the electrical axis of the heart

Signs of horizontal position of e.o.s. ( angle α=0°)

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Sinus rhythm. The voltage is satisfactory.

Normal position of the electrical axis of the heart

ECG 2. NORMAL POSITION OF THE ELECTRICAL AXIS OF THE HEART

Sinus arrhythmia of the heart EOS vertical

Discounts » History » Sinus arrhythmia of the heart EOS vertical

Sinus arrhythmia, causes of its occurrence and main symptoms. Diagnostic criteria. Sinus arrhythmia is a normal change in heart rate. The concept of cardiography combines different methods of studying cardiac activity. Good afternoon. Please tell me. I did a cardiogram and heart ultrasound for my children. Cardiac arrhythmia can manifest itself in cases of dysfunction of the autonomic nervous system, a. What ECG signs are observed with sinus arrhythmia. Sinus arrhythmia happens. Okg cardiology Description. The right rhythm. Sinus waves p are of normal configuration (their amplitude varies).

1. Sinus arrhythmia of the heart
2. Sinus arrhythmia all questions and
3. Cardiography of the heart and blood vessels
4. Child's cardiogram result
5. Arrhythmia – medicine consultations

Now almost every ambulance team is equipped with a portable, lightweight and mobile one. Decoding the cardiogram in children and adults general principles, reading the results, example. When recording an ECG in twelve conventional leads, practically no signs are detected. Eos is short for electrical axis of the heart - this indicator. Thin people usually have a vertical position of the eos, while thick people and faces have a vertical position. Sinus arrhythmia is an abnormal sinus rhythm with periods.

Sinus arrhythmia is an abnormal heart rhythm that... The vertical position of the heart axis is sinus arrhythmia, do not be alarmed. Sinus arrhythmia (irregular sinus rhythm). This term means. Their average contraction frequency is 138 beats, the eos is vertical. Vertical electrical position of the heart (or vertical. Sinus arrhythmia can be respiratory (associated with phases.). I did an ultrasound of the heart after a cardiogram with sinus arrhythmia. Sinus arrhythmia, the position of the eospolus is vertical vagal. The electrical activity of the heart is recorded on the ECG, which changes. The normal position of the electrical axis of the heart is 3069o, vertical. Deviation of the electrical axis of the heart (EOS) to the left or right. The conclusion was written by sinus arrhythmia with tendon. Symptoms of blood cancer after 40 years. And she sometimes points her finger to her chest in the area of ​​​​the heart and says that she has. Hello. Sinus arrhythmia - one of the most. In the 4th stage, qt 0.28 in the 4th stage, sinus arrhythmia 111-150, vertical position of the eos. Deviation of the electrical axis of the heart (eos) to the right (angle a 90170). In most infants, the eos moves to a vertical position. On average up to 110120 beats, some children develop sinus arrhythmia.

Mild sinus arrhythmia (vertical position of the eos) is also not a diagnosis. What already. Sinus arrhythmia of the heart, the causes of which can be completely different, can be as follows. Conclusion: sinus rhythm, pronounced arrhythmia with heart rate from 103 to 150. Eos, incomplete blockade of the right bundle branch. Ultrasound of the heart at 2 years old. The conclusion is sinus arrhythmia, EOS vertical bradycardia. Eos is short for electrical axis of the heart - this indicator allows. Sinus arrhythmia is an abnormal sinus rhythm with periods.

Sinus rhythm with heart rate 71 eos vertical metabolic change in the myocardium. Eos (electrical axis of the heart), however, it will be correct. Reduced wave voltage, sinus tachycardia, diffuse changes in the myocardium. It was written that I have sinus arrhythmia (severe) vertical electrical position of the heart. Tell me, is this serious? An ECG records the electrical activity of the heart, which changes cyclically. Deviation of the electrical axis of the heart (EOS) to the left or right is possible with hypertrophy of the left or. Electrical position is vertical. The conclusion was written as sinus arrhythmia with Qrst0.26 n e. The cardiac axis is not deviated. According to the ECG data, the conclusion is sinus arrhythmia, EOS vertical bradycardia. Violation. The following are typical for physiological cardiac hypertrophy in athletes. Sinus arrhythmia indicates a dysregulation of the sinus node and... Vertical eos is more often observed in football players and skiers. Symptoms of skin cancer on the hands Deviation of the eos to the left. 40 is blocked, sinus arrhythmia of the heart, they prescribed Concor and statins, will Concor lower the blood pressure. Hello. I’m 26 years old. Severe sinus arrhythmia on Holter is scary? Open. Sinus arrhythmia is common in healthy people. Found. Deviation of EOS to the left. The coronary artery is 40 blocked, sinus arrhythmia of the heart, they prescribed Concor and statins, will Concor lower the blood pressure. Yesterday we did an ultrasound of the heart, and the doctor diagnosed sinus tachycardia. Registered. Sinus tachycardia, moderate arrhythmia, coraxan. Sinus tachycardia, vertical position of the eos and shortening of the interval. II degree - mild sinus arrhythmia, rhythm fluctuations within limits. The power of the heart is represented by the electrical axis of the heart (EOS). Eos is short for electrical axis of the heart - this indicator. Thin people usually have a vertical position of the eos, while thick people and faces have a vertical position. Sinus arrhythmia is an abnormal sinus rhythm with periods.

Posted: 10 Feb 2015

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An electrocardiogram provides useful information for diagnosing cardiovascular diseases in children. Decoding the results of the cardiogram allows you to obtain data on the state of the heart muscle, the frequency and rhythm of heart contractions.

ATTENTION! Before asking a question, we recommend that you read the contents of the “Frequently Asked Questions” section. There is a high probability that you will find the answer to your question there right now, without wasting time waiting for an answer from a consultant doctor.

Rimma asks.

Hello! My son is 4 years old. At an appointment with a pediatrician, they listened to a heart murmur and did an ECG: sinus bradycardia with a heart rate of 88 per minute, vertical position of the EOS, incomplete block of the right bundle branch. They sent me for a consultation with a cardiologist. Please explain how serious this is? What does this even mean?

information about the consultant

As for the conclusion about your child’s condition, the best answer to this question is a pediatric cardiologist, who will be familiar not only with the description of the cardiogram, but also with the entire history of the child’s health, and will also examine him in person.

Methods for determining the position of the EOS.

1. Visual.

2. Graphic - using various coordinate systems (Einthoven triangle, Bailey's 6-axis scheme, Diede scheme).

3. From tables or diagrams.

Visual determination of the EOS position – used for rough estimation.

1 way. Assessment based on 3 standard leads.

To determine the position of the EOS, pay attention to the severity of the amplitude of the R waves and the ratio of the R and S waves in standard leads.

Note: if you write standard leads in Arabic numerals (R 1, R 2, R 3), then it is easy to remember the serial number of the digits according to the size of the R wave in these leads: normogram - 213, rightogram - 321, leftogram - 123.

Method 2. Assessment using 6 limb leads.

To determine the position of the EOS, first they are guided by three standard leads, and then pay attention to the equality of the R and S waves in standard and reinforced ones.

3 way. Assessment using the 6-axis Bayley system (limb leads).

This method gives a more accurate estimate. To determine the position of the EOS, successive steps must be taken.

Step 1. Find the lead in which the algebraic sum of the amplitudes of the QRS complex waves approaches 0 (R=S or R=Q+S). The axis of this lead is approximately perpendicular to the desired EOS.

Step 2. Find one or two leads in which the algebraic sum of the QRS complex waves has a positive maximum value. The axes of these leads approximately coincide with the direction of the EOS

Step 3. Compare the results of the first and second steps and draw a final conclusion. Knowing the angle at which the lead axes are located, determine the angle α.

To determine the angle α graphically or using the tables of R.Ya. Pismenny it is necessary to calculate the algebraic sum of the amplitudes of the QRS complex waves sequentially in standard leads I and then in standard leads III. To obtain the algebraic sum of the waves of the QRS complex in any lead, it is necessary to subtract the amplitude of the negative waves from the amplitude of the R wave, i.e. S and Q. If the dominant wave of the QRS complex is R, then the algebraic sum of the waves will be positive, and if S or Q, it will be negative.

The obtained values ​​are plotted on the axis of the corresponding leads and the angle α is graphically determined in any of the listed coordinate systems. Or, using the same data, the angle α is determined according to the tables of R.Ya. Pismenny (see tables 5, 6, 7 of the appendix, there are also rules for using the tables).

Exercise: on the ECG, independently calculate the angle α and determine the position of the EOS using the listed methods.

6. Analysis of waves, intervals, ECG complexes

6.1. Prong R. Analysis of the P wave involves determining its amplitude, width (duration), shape, direction and severity in various leads.

6.1.1. Determination of P wave amplitude and its assessment. The P wave is small in size from 0.5 to 2.5 mm. Its amplitude should be determined in the lead where it is most clearly expressed (most often in standard leads I and II).

6.1.2. Determination of P wave duration and its assessment. The P wave is measured from the beginning of the P wave to its end. Standard indicators for assessment are given in Table 3 of the Appendix.

6.1.3. Degree of severity and direction of the P wave depend on the magnitude and direction of the electrical axis of the vector P, which occurs during excitation of the atria. Therefore, in different leads the size and direction of the P wave change from well-defined positive to smoothed, biphasic or negative. The P wave is more pronounced in the limb leads and weakly in the thoracic leads. In most leads, the positive P wave predominates (I, II, aVF, V 2 -V 6), because vector P is projected onto the positive parts of most leads (but not all!). The always negative wave vector P is projected onto the positive parts of most leads (but not all!). negative P wave in lead aVR. In leads III, aVL, V 1 can be weakly positive or biphasic, and in leads III, aVL it can sometimes be negative.

6.1.4. P wave shape should be smooth, rounded, dome-shaped. Sometimes there may be a slight jaggedness at the apex due to non-simultaneous coverage of the right and left atria by excitation (no more than 0.02-0.03 s).

6.2. PQ interval. The PQ interval is measured from the beginning of the P wave to the beginning of the Q wave (R). For measurement, select the lead from the limbs where the P wave and the QRS complex are well defined, and in which the duration of this interval is greatest (usually standard lead II). In the chest leads, the duration of the PQ interval may differ from its duration in the limb leads by 0.04 s or even more. Its duration depends on age and heart rate. The younger the child’s age and the higher the heart rate, the shorter the PQ interval. Standard indicators for assessment are given in Table 3 of the Appendix.

6.3. QRS complex – the initial part of the ventricular complex.

6.3.1. Designation of the QRS complex waves depending on their amplitude. If the amplitude of the R and S waves is more than 5 mm, and Q is more than 3 mm, they are designated by capital letters of the Latin alphabet Q, R, S; if less, then in lowercase letters q, r, s.

6.3.2. Designation of the teeth of the QRS complex when there are several R or S waves in the complex. If there are several R waves in the QRS complex, they are designated R, R', R” (r, r', r”), respectively; if there are several S waves, then – S, S', S” (s, s', s” ). The sequence of teeth is as follows - the negative tooth preceding the first R wave is designated by the letter Q (q), and the negative tooth immediately following the R wave and before the R’ wave is designated by the letter S (s).

6.3.3. The number of teeth of the QRS complex in various leads. The QRS complex can be represented by three waves - QRS, two - QR, RS, or one wave - R or the QS complex. This depends on the position (orientation) of the QRS vector relative to the axis of a particular lead. If the vector is perpendicular to the lead axis, then 1 or even 2 teeth of the complex may not be registered.

6.3.4. Measuring the duration of the QRS complex and its evaluation. The duration of the QRS complex (width) is measured from the beginning of the Q (R) wave to the end of the S (R) wave. It is best to measure the duration in standard leads (usually in II), taking into account the greatest width of the complex. With age, the width of the QRS complex increases. Standard indicators for assessment are given in Table 3 of the Appendix.

6.3.5. Amplitude of the QRS complex (ECG voltage) varies significantly. In chest leads it is usually greater than in standard leads. The amplitude of the QRS complex is measured from the top of the R wave to the top of the S wave. Normally, it should exceed 5 mm in at least one of the standard or enhanced limb leads, and 8 mm in the precordial leads. If the amplitude of the QRS complex is less than the numbers mentioned or the sum of the amplitudes of the R waves in three standard leads is less than 15 mm, then the ECG voltage is considered reduced. An increase in voltage is considered to be an excess of the maximum permissible amplitude of the QRS complex (in the limb lead - 20-22 mm, in the chest lead - 25 mm). However, it should be taken into account that the terms “decrease” and “increase” in the voltage of ECG waves do not differ in the accuracy of the accepted criteria, because There are no standards for the amplitude of the teeth depending on the body type and different thickness of the chest. Therefore, it is not so much the absolute size of the QRS complex waves that is important, but their ratio in terms of amplitude indicators.

6.3.6. Comparison of amplitudes and R and S waves in different leads important for determining

- EOS directions(angle α in degrees) – see section 5;

- transition zone. So called chest lead, in which the amplitude of the R and S waves is approximately the same. When moving from the right to the left chest leads, the ratio of the R/S teeth gradually increases, because the height of the R waves increases and the depth of the S waves decreases. The position of the transition zone changes with age. In healthy children (except for children 1 year of age) and adults, it is most often recorded in lead V 3 (V 2 -V 4). Analysis of the QRS complex and transition zone allows us to assess the dominance of electrical activity of the right or left ventricles and the rotation of the heart around the longitudinal axis clockwise or counterclockwise. The localization of the transition zone in V 2 -V 3 indicates the dominance of the left ventricle;

- rotations of the heart around its axes(antero-posterior, longitudinal and transverse).

6.4. Q wave. Analysis of the Q wave involves determining its depth, duration, severity in various leads, and comparing its amplitude with the R wave.

6.4.1. Depth and width of the Q wave. More often, the Q wave has a small size (up to 3 mm, type q) and a width of 0.02-0.03 s. In lead aVR, a deep (up to 8 mm) and wide Q wave, such as Qr or QS, can be recorded. An exception is also Q III, which can be up to 4-7 mm deep in healthy individuals.

6.4.2. The degree of severity of the Q wave in various leads. The Q wave is the most unstable wave of the ECG, so it may not be registered in some leads. More often it is detected in the limb leads, more pronounced in I, II, aVL, aVF and, especially, in aVR, as well as in the left thoracic (V 4 -V 6). In the right chest, especially in leads V 1 and V 2, as a rule, it is not recorded.

6.4.3. The ratio of the amplitude of the Q and R waves. In all leads where the Q wave is recorded (except for aVR), its depth should not exceed ¼ of the amplitude of the following R wave. The exception is lead aVR, in which the deep Q wave significantly exceeds the amplitude of the r wave.

6.5. R wave Analysis of the R wave involves determining the degree of severity in different leads, amplitude, shape, interval of internal deviation, comparison with the S wave (sometimes with Q) in different leads.

6.5.1. The degree of severity of the R wave in different leads. The R wave is the highest wave of the ECG. The highest R waves are recorded in the chest leads, slightly less high - in the standard ones. The degree of its severity in different leads is determined by the position of the EOS.

- In the normal position of the EOS in all limb leads (except aVR), high R waves are recorded with a maximum in standard lead II (with R II > R I > R III). In the chest leads (except V 1), high R waves with a maximum in V 4 are also recorded. In this case, the amplitude of the R waves increases from left to right: from V 2 to V 4, then from V 4 to V 6 it decreases, but the R waves in the left chest leads are higher than in the right ones. And only in two leads (aVR and V 1) the R waves have minimal amplitude or are not recorded at all, and then the complex has the appearance of QS.

- the highest R wave is recorded in lead aVF, slightly smaller R waves in standard leads III and II (with R III >R II >R I and R aVF >R III), and in standard leads aVL and I the R waves are small, in aVL is sometimes absent.

- the highest R waves are recorded in standard I and aVL leads, somewhat smaller in standard leads II and III (with R I >R II >R III) and in lead aVF.

6.5.2. Determination and evaluation of R wave amplitude. Fluctuations in the amplitude of the R waves in various leads range from 3 to 15 mm depending on age, width 0.03-0.04 sec. The maximum permissible height of the R wave in standard leads is up to 20 mm, in chest leads – up to 25 mm. Determining the amplitude of the R waves is important for assessing the ECG voltage (see paragraph 6.3.5.).

6.5.3. R wave shape should be smooth, pointed, without notches and splits, although their presence is allowed if they are not at the top, but closer to the base of the wave, and if they are determined in only one lead, especially on low R waves.

6.5.4. Determination of the internal deviation interval and its evaluation. The internal deviation interval gives an idea of ​​the duration of activation of the right (V 1) and left (V 6) ventricles. It is measured along the isoelectric line from the beginning of the Q (R) wave to the perpendicular lowered from the top of the R wave to the isoelectric line, in the chest leads (V 1, V 2 - right ventricle, V 5, V 6 - left ventricle). The duration of ventricular activation in the right precordial leads changes little with age, but in the left precordial leads it increases. Norm for adults: in V 1 no more than 0.03 s, in V 6 no more than 0.05 s.

6.6. S wave Analysis of the S wave involves determining the depth, width, shape, severity in different leads and comparison with the R wave in different leads.

6.6.1. Depth, width and shape of the S wave. The amplitude of the S wave varies widely: from absence (0 mm) or shallow depth in a few leads (especially in standard leads) to a large value (but not more than 20 mm). More often, the S wave is of small depth (from 2 to 5 mm) in the limb leads (except aVR) and quite deep in leads V 1 -V 4 ​​and in aVR. The width of the S wave is 0.03 s. The shape of the S wave should be smooth, pointed, without notches or splits.

6.6.2. The degree of severity of the S wave (depth) in different leads depends on the position of the EOS and changes with age.

- In the normal position of the EOS in the limb leads, the deepest S wave is determined in aVR (rS or QS type). In the remaining leads, the S wave of small depth is recorded, most pronounced in the II standard and aVF leads. In the chest leads, the greatest amplitude of the S wave is usually observed in V 1, V 2 and gradually decreases from left to right from V 1 to V 4, and in leads V 5 and V 6 the S waves are small or not recorded at all.

- When the EOS is in a vertical position The S wave is most pronounced in leads I and aVL.

- When the EOS is in a horizontal position The S wave is most pronounced in leads III and aVF.

6.7. ST segment – a segment from the end of the S (R) wave to the beginning of the T wave. Its analysis involves determination of isoelectricity and degree of displacement. To determine the isoelectricity of the ST segment, one should focus on the isoelectric line of the TP segment. If the TR segment is not located on the isoline or is poorly expressed (with tachycardia), focus on the PQ segment. The junction of the end of the S (R) wave with the beginning of the ST segment is indicated by the point “j”. Its location is important in determining the displacement of the ST segment from the isoline. If there is a displacement of the ST segment, it is necessary to indicate its value in mm and describe the shape (convex, concave, horizontal, oblique-ascending, oblique-descending, etc.). In a normal ECG, the ST segment does not completely coincide with the isoelectric line. The exact horizontal direction of the ST segment in all leads (except III) can be considered pathological. The deviation of the ST segment in the limb leads is allowed up to 1 mm upward and up to 0.5 mm downward. In the right precordial leads, a deviation of up to 2 mm upward is allowed, and in the left - up to 1.0 mm (usually downward).

6.8. T wave Analysis of the T wave involves determining the amplitude, width, shape, severity and direction in various leads.

6.8.1. Determination of the amplitude and duration (width) of the T wave. There are fluctuations in the amplitude of the T wave in different leads: from 1 mm to 5-6 mm in leads from the extremities to 10 mm (rarely up to 15 mm) in the chest leads. The duration of the T wave is 0.10-0.25 s, but it is determined only in pathology.

6.8.2. T wave shape. A normal T wave is somewhat asymmetrical: it has a flat ascending bend, a rounded apex, and a steeper descending bend.

6.8.3. The degree of severity (amplitude) of the T wave in different leads. The amplitude and direction of the T wave in various leads depend on the magnitude and orientation (position) of the ventricular repolarization vector (T vector). Vector T has almost the same direction as vector R, but less magnitude. Therefore, in most leads the T wave is small and positive. In this case, the largest R wave in various leads corresponds to the largest T wave in amplitude and vice versa. In standard leads T I > T III. In the chest - the height of the T wave increases from left to right from V 1 to V 4 with a maximum at V 4 (sometimes in V 3), then decreases slightly towards V 5 -V 6, but T V 6 >T V1.

6.8.4. Direction of the T wave in different leads. In most leads (I, II, aVF, V 2 -V 6) the T wave is positive; in lead aVR – always negative; in III, aVL, V 1 (sometimes V 2) can be slightly positive, negative or biphasic.

6.9. U wave rarely recorded on ECG. This is a small (up to 1.0-2.5 mm) positive wave, following after 0.02-0.04 seconds or immediately after the T wave. The origin is not completely clear. It is assumed that it reflects the repolarization of the fibers of the cardiac conduction system. More often it is recorded in the right chest leads, less often in the left chest leads, and even less often in the standard ones.

6.10. QRST complex – ventricular complex (electrical ventricular systole). Analysis of the QRST complex involves determining its duration, the value of the systolic indicator, the ratio of the time of excitation and the time of cessation of excitation.

6.10.1. Determination of the duration of the QT interval. The QT interval is measured from the beginning of the Q wave to the end of the T (U) wave. Normally it is 0.32-0.37 s for men, 0.35-0.40 s for women. The duration of the QT interval depends on age and heart rate: the younger the child’s age and the higher the heart rate, the shorter the QT (see Appendix Table 1).

6.10.2. QT interval assessment. The QT interval found on the ECG should be compared with the standard, which is either given in the table (see Table 1 of the Appendix), where it is calculated for each heart rate value (R-R), or can be approximately determined using the Bazett formula: , where K is a coefficient equal to 0 .37 for men; 0.40 for women; 0.41 for children under 6 months of age and 0.38 for children under 12 years of age. If the actual QT interval is 0.03 s or more longer than normal, then this is regarded as a prolongation of the electrical systole of the ventricles. Some authors distinguish two phases in the electrical systole of the heart: the excitation phase (from the beginning of the Q wave to the beginning of the T wave - Q-T 1 interval) and the recovery phase (from the beginning of the T wave to its end - T 1 -T interval).

6.10.3. Determination of systolic index (SP) and its assessment. The systolic indicator is the ratio of the duration of the electrical systole in seconds to the total duration of the cardiac cycle (RR) in seconds, expressed in %. The SP standard can be determined from the table depending on the heart rate (RR duration) or calculated using the formula: SP = QT / RR x 100%. The SP is considered increased if the actual indicator exceeds the standard by 5% or more.

7. Plan (scheme) for deciphering the electrocardiogram

Analysis (interpretation) of the ECG includes all the positions outlined in the section “Analysis and characteristics of the elements of the electrocardiogram”. To better remember the sequence of actions, we present a general diagram.

1. Preparatory stage: getting to know the child’s data – age, gender, main diagnosis and concomitant diseases, health group, etc.

2. Checking the standards of ECG recording technology. ECG voltage.

3. A quick scan of the entire tape to obtain preliminary data on the presence of pathological changes.

4. Heart rate analysis:

a. determination of heart rhythm regularity,

b. definition of pacemaker,

c. counting and assessing the number of heartbeats.

5. Conductivity analysis and assessment.

6. Determination of the position of the electrical axis of the heart.

7. Analysis of the P wave (atrial complex).

8. Analysis of the ventricular QRST complex:

a. QRS complex analysis,

b. S(R)T segment analysis,

c. T wave analysis,

d. analysis and evaluation of the QT interval.

9. Electrocardiographic report.

8. Electrocardiographic report

The electrocardiographic conclusion is the most difficult and important part of the ECG analysis.

In conclusion, it should be noted:

Source of heart rhythm (sinus, non-sinus);

Rhythm regularity (correct, incorrect) and heart rate;

EOS position;

ECG intervals, a brief description of ECG waves and complexes (if there are no changes, indicate that the ECG elements correspond to the age norm);

Changes in individual elements of the ECG with an attempt to interpret them from the point of view of a supposed violation of electrophysiological processes (if there are no changes, this point is omitted).

ECG is a method of very high sensitivity, capturing a wide range of functional and metabolic changes in the body, especially in children, so ECG changes are often non-specific. Identical ECG changes can be observed in various diseases, and not only of the cardiovascular system. Hence the difficulty of interpreting the found pathological indicators. ECG analysis must be carried out after familiarization with the patient's medical history and clinical picture of the disease, and a clinical diagnosis cannot be made from the ECG alone. When analyzing children's ECGs, small changes are often detected even in apparently healthy children and adolescents. This is due to the processes of growth and differentiation of heart structures. But it is important not to miss the early signs of ongoing pathological processes in the myocardium. It should be borne in mind that a normal ECG does not necessarily indicate the absence of changes in the heart and vice versa.

At absence of pathological changes indicate that ECG is an option age norm.

ECG having deviations from the norm, should be classified. There are 3 groups.

Group I. ECG with changes (syndromes) related to age norm options.

Group II. Borderline ECGs. Changes (syndromes) requiring mandatory in-depth examination and long-term monitoring over time with ECG monitoring.