ECG horizontal position EOS. Deviation of EOS to the left treatment

Article publication date: 05/14/2017

Article updated date: 12/21/2018

From this article you will learn what EOS is and what it should be normally. When the EOS is deviated slightly to the left - what does this mean, what diseases can it indicate. What treatment may be required.

The electrical axis of the heart is diagnostic criterion, which displays the electrical activity of the organ.

The electrical activity of the heart is recorded using an ECG. Sensors are placed on different areas of the chest, and to find out the direction electrical axis, you can imagine it ( chest) in the form of a three-dimensional coordinate system.

The direction of the electrical axis is calculated by the cardiologist during the course. To do this, he sums the values ​​of the Q, R and S waves in lead 1, then finds the sum of the values ​​of the Q, R and S waves in lead 3. Next, it takes the two obtained numbers and calculates the alpha angle using a special table. It's called the Diede table. This angle is the criterion by which it is determined whether the location of the electrical axis of the heart is normal.

The presence of a significant deviation of the EOS to the left or right is a sign of cardiac dysfunction. Diseases that provoke EOS deviation almost always require treatment. After getting rid of the underlying disease, the EOS takes a more natural position, but sometimes it is impossible to completely cure the disease.

To resolve this problem, consult a cardiologist.

The location of the electrical axis is normal

In healthy people, the electrical axis of the heart coincides with the anatomical axis of this body. The heart is located semi-vertically - its lower end is directed down and to the left. And the electrical axis, like the anatomical one, is in a semi-vertical position and tends down and to the left.

The standard alpha angle is from 0 to +90 degrees.

The location of the anatomical and electrical axes depends to some extent on body type. In asthenics (thin people with tall stature and long limbs), the heart (and, accordingly, its axes) is located more vertically, while in hypersthenics (not tall people stocky build) - more horizontal.

Normal alpha angle depending on body type:

Significant displacement of the electrical axis to the left or right side- This is a sign of pathologies of the conduction system of the heart or other diseases.

A deviation to the left is indicated by a minus alpha angle: from -90 to 0 degrees. About its deviation to the right - values ​​from +90 to +180 degrees.

However, it is not at all necessary to know these numbers, since in case of violations in the ECG interpretation you can find the phrase “EOS is deviated to the left (or right).”

Reasons for shift to the left

Deviation of the electrical axis of the heart to the left – typical symptom problems with the left side of this organ. It could be:

• hypertrophy (enlargement, proliferation) of the left ventricle (LVH);
• – Impaired impulse conduction in the anterior part of the left ventricle.

Causes of these pathologies:

Symptoms

EOS displacement itself does not have characteristic symptoms.

The diseases that accompany it can also be asymptomatic. That is why it is important to undergo an ECG for preventive purposes - if the disease is not accompanied by unpleasant symptoms, you can find out about it and begin treatment only after deciphering the cardiogram.

However, sometimes these diseases still make themselves felt.

Symptoms of diseases that are accompanied by a displacement of the electrical axis:

But let us repeat once again - symptoms do not always appear; they usually develop late stages diseases.

Additional diagnostics

To find out the reasons for the EOS deviation, the ECG is analyzed in detail. They may also assign:

After a detailed examination, appropriate therapy is prescribed.

Treatment

The deviation of the electrical axis of the heart to the left in itself does not require specific treatment because it is just a symptom of another disease.

All measures are aimed at eliminating the underlying disease, which is manifested by displacement of the EOS.

Treatment for LVH depends on what caused the myocardial growth

Treatment of blockade of the anterior branch of the left bundle branch - . If it occurs as a result of a heart attack - surgical repair blood circulation in the coronary vessels.

The electrical axis of the heart returns to normal only if the size of the left ventricle is returned to normal or the conduction of impulses through the left ventricle is restored.

If the EOS is deviated to the left, what does this mean, you need to find out from your doctor. The conclusion is made after examining the patient and analyzing the clinical parameter.

Medical indicators

Using the electrical axis of the heart, cardiologists evaluate the electrical processes that move the heart muscles. The direction of EOS depends on various anatomical and physiological factors. Average rate indicator is +590. Normally, the EOS value fluctuates between +200...+1000.

The patient is examined in a specialized room, which is shielded from various electrical noise. The patient takes a supine position with a pillow placed under his head. To take an ECG, electrodes are applied. Data is recorded during quiet breathing. At the same time, the device records the frequency and regularity of heartbeats, including the position of the EOS and other parameters.

U healthy person deviation of the electrical axis of the heart to the left is allowed when:

• deep exhalation;
• changing body position;
• body features (hypersthenic).

The EOS shifts to the right in a healthy person when:

• the end of a deep breath;
• body features (asthenic).

The location of the EOS is determined by the mass of the 2 parts of the ventricle. The indicator under consideration is determined using 2 methods.

In the first case, the specialist identifies a displacement in the alpha angle. The value of the main indicator is calculated using a special table according to Diede.

In the second case, the specialist compares the R and S waves in leads 1 and 3. A sharp deviation of the EOS in any direction is not an independent pathology.

An electrical axis shifted to the left indicates the following problems:

• left ventricular hypertrophy;
• impaired functioning of the left ventricular valve;
• cardiac blockade.

The above phenomena lead to incorrect functioning of the left ventricle. Any deviation of EOS indicates pathologies such as ischemia, CHF, congenital heart disease, and heart attack. Blockade of the conduction system of the main organ is associated with taking certain medications.

Additional diagnostic techniques

If a deviation of the electrical axis to the left is recorded on the cardiogram, additional instrumental examination of the patient is performed. It is recommended to have an electrocardiogram while walking on a treadmill or exercise bike. Using ultrasound, the degree of ventricular hypertrophy is assessed.

If sinus rhythm is disturbed, EOS is rejected, daily monitoring Holter ECG. Data is recorded throughout the day. If the myocardial tissue is significantly hypertrophied, a chest x-ray is performed. Using angiography of the coronary arteries, the degree of vascular damage during current ischemia is determined. Echocardioscopy allows you to determine the condition of the atria and ventricles of the heart.

Therapy for the phenomenon under consideration is aimed at eliminating the underlying disease. Some heart pathologies are treated medically. Additionally, it is recommended to eat right and healthy image life.

At severe course the disease requires surgical intervention. If the conduction system is seriously impaired, a pacemaker transplant is performed. This device sends signals to the myocardium, causing it to contract.

Most often, the phenomenon in question does not threaten human life. But, if a sharp change in the position of the axis is diagnosed (value greater than +900), this can lead to cardiac arrest. Such a patient must be urgently hospitalized intensive care. To prevent this condition, annual scheduled examinations by a cardiologist are indicated.

Changes to the right

Deviation of the axis to the right is not an independent pathology, but is diagnostic symptom disorders of the functioning of the main organ. Most often, such a clinic indicates an abnormal enlargement of the right atrium or ventricle. After clarification exact reason the development of this anomaly, the doctor makes a diagnosis.

If necessary, the patient is prescribed additional diagnostics:

1. 1. Ultrasound - provides information about changes in the anatomy of the main organ.
2. 2. Chest X-ray - reveals myocardial hypertrophy.
3. 3. Daily ECG - performed for concomitant rhythm disturbances.
4. 4. ECG during exercise - helps to detect myocardial ischemia.
5. 5. CAG - performed to diagnose lesions of the coronary artery.

Deviation of the axis to the right can be caused by the following pathologies:

1. 1. Ischemia is an incurable pathology in which there is blockage of the coronary arteries. If left untreated, the disease can lead to myocardial infarction.
2. 2. Acquired or congenital stenosis of the pulmonary artery - due to the narrowing of the vessel, the normal flow of blood from the right ventricle stops, which provokes an increase in blood pressure.
3. 3. Atrial fibrillation - can provoke a cerebral stroke.
4. 4. Chronic cor pulmonale- observed with impaired lung function, chest pathology. Under such conditions, hypertrophy may develop.
5. 5. The presence of a hole in the septum between the atria, through which blood is ejected from left to right. This provokes the development of heart failure.
6. 6. Valve stenosis - manifests itself as a narrowing of the opening between the left ventricle and the corresponding atrium, which impedes the diastolic movement of blood. This pathology is acquired.
7. 7. Pulmonary embolism - provoked by blood clots that occur in large vessels. They then move through the system, clogging the artery and its branches.
8. 8. Primary pulmonary hypertension, which is accompanied high pressure blood caused by various reasons.

The electrical axis of the heart (EOS) is one of the main parameters of the electrocardiogram. This term is actively used both in cardiology and in functional diagnostics, reflecting the processes occurring in the most important organ human body.

The position of the electrical axis of the heart shows the specialist what exactly is happening in the heart muscle every minute. This parameter is the sum of all bioelectrical changes observed in the organ. When taking an ECG, each electrode of the system registers excitation passing at a strictly defined point. If you transfer these values ​​to a conventional three-dimensional coordinate system, you can understand how the electrical axis of the heart is located and calculate its angle relative to the organ itself.

Before discussing the direction of the electrical axis, you should understand what the conduction system of the heart is. It is this structure that is responsible for the passage of impulses through the myocardium. The conduction system of the heart is atypical muscle fibers, connecting different parts of the organ. It begins with the sinus node, located between the mouths of the vena cava. Next, the impulse is transmitted to the atrioventricular node, located in the lower part of the right atrium. The next to take up the baton is the His bundle, which quickly diverges into two legs - left and right. In the ventricle, the branches of the His bundle immediately become Purkinje fibers, which penetrate the entire cardiac muscle.

EOS location options

Cardiac ischemia;

Chronic heart failure;

Cardiomyopathies of various origins;

Congenital defects.

Why is changing EOS dangerous?

The normal EOS value is considered to be the range from +30 to +70°.

Horizontal (from 0 to +30°) and vertical (from +70 to +90°) positions of the heart axis are acceptable values and do not talk about the development of any pathology.

Deviations of the EOS to the left or to the right may indicate various disorders in the conduction system of the heart and require consultation with a specialist.

A change in EOS detected on a cardiogram cannot be made as a diagnosis, but is a reason to visit a cardiologist.

The heart is an amazing organ that ensures the functioning of all systems of the human body. Any changes that occur in it inevitably affect the functioning of the whole organism. Regular examinations by a therapist and an ECG will allow timely detection of serious illnesses and avoid the development of any complications in this area.

The electrical axis of the heart is a concept that reflects the total vector of the electrodynamic force of the heart, or its electrical activity, and practically coincides with the anatomical axis. Normally, this organ has a cone-shaped shape, with its narrow end directed downwards, forward and to the left, and the electrical axis has a semi-vertical position, that is, it is also directed downwards and to the left, and when projected onto the coordinate system it can be in the range from +0 to +90 0.

An ECG conclusion is considered normal if it indicates any of the following positions of the heart axis: not deviated, semi-vertical, semi-horizontal, vertical or horizontal position. The axis is closer to the vertical position in thin, tall people asthenic build, and to the horizontal - in strong stocky persons of hypersthenic physique.

Electric axis position range is normal

For example, in the conclusion of an ECG, the patient may see the following phrase: “sinus rhythm, EOS is not deviated...”, or “the axis of the heart is in a vertical position,” this means that the heart is working correctly.

In the case of heart disease, the electrical axis of the heart, along with the heart rhythm, is one of the first ECG criteria that the doctor pays attention to, and when interpreting the ECG, the attending physician must determine the direction of the electrical axis.

Deviations from the norm are deviation of the axis to the left and sharply to the left, to the right and sharply to the right, as well as the presence of non-sinus heart rate.

How to determine the position of the electrical axis

Determination of the position of the heart axis is carried out by a functional diagnostics doctor who deciphers the ECG using special tables and diagrams using the angle α (“alpha”).

The second way to determine the position of the electrical axis is to compare the QRS complexes responsible for the excitation and contraction of the ventricles. So, if the R wave has a greater amplitude in the I chest lead than in the III, then there is a levogram, or deviation of the axis to the left. If there is more in III than in I, then it is a legal grammar. Normally, the R wave is higher in lead II.

Reasons for deviations from the norm

Axial deviation to the right or left is not considered an independent disease, but it can indicate diseases that lead to disruption of the heart.

Deviation of the heart axis to the left often develops with left ventricular hypertrophy

Deviation of the heart axis to the left can occur normally in healthy individuals who are professionally involved in sports, but more often develops with left ventricular hypertrophy. This is an increase in the mass of the heart muscle with a violation of its contraction and relaxation, necessary for the normal functioning of the entire heart. Hypertrophy can be caused by the following diseases:

• cardiomyopathy (increase in myocardial mass or expansion of the heart chambers), caused by anemia, hormonal imbalances in the body, coronary disease heart, post-infarction cardiosclerosis. changes in myocardial structure after myocarditis ( inflammatory process in cardiac tissue);
• long-standing arterial hypertension, especially with constantly high blood pressure numbers;
• acquired heart defects, in particular stenosis (narrowing) or insufficiency (incomplete closure) aortic valve, leading to disruption of intracardiac blood flow, and, consequently, increased load on the left ventricle;
• congenital heart defects often cause a deviation of the electrical axis to the left in a child;
• conduction disturbance along the left bundle branch - complete or incomplete blockade, leading to impaired contractility of the left ventricle, while the axis is deviated, and the rhythm remains sinus;
• atrial fibrillation, then the ECG is characterized not only by axis deviation, but also by the presence of non-sinus rhythm.

Deviation of the heart axis to the right is a normal variant when conducting an ECG in a newborn child, and in this case it may occur sharp deviation axes.

In adults, such a deviation is usually a sign of right ventricular hypertrophy, which develops in the following diseases:

• diseases bronchopulmonary system– long-term bronchial asthma, severe obstructive bronchitis, pulmonary emphysema, leading to increased blood pressure in the pulmonary capillaries and increasing the load on the right ventricle;
• heart defects with damage to the tricuspid (three-leaf) valve and the valve of the pulmonary artery, which arises from the right ventricle.

The greater the degree of ventricular hypertrophy, the more the electrical axis is deflected, respectively, sharply to the left and sharply to the right.

Symptoms

The electrical axis of the heart itself does not cause any symptoms in the patient. The patient feels unwell if myocardial hypertrophy leads to pronounced violations hemodynamics and heart failure.

The disease is characterized by pain in the heart area

Signs of diseases accompanied by deviation of the heart axis to the left or right include headaches, pain in the heart area, swelling of the lower extremities and face, shortness of breath, asthma attacks, etc.

If any unpleasant cardiac symptoms appear, you should consult a doctor for an ECG, and if an abnormal position of the electrical axis is detected on the cardiogram, further examination must be performed to determine the cause of this condition, especially if it is detected in a child.

Diagnostics

To determine the reason for deviation according to ECG axis heart left or right, a cardiologist or therapist can prescribe additional methods research:

1. Cardiac ultrasound is the most informative method for assessing anatomical changes and identify ventricular hypertrophy, as well as determine the degree of impairment of their contractile function. This method is especially important for examining a newborn child for congenital heart pathology.
2. ECG with exercise (walking on a treadmill - treadmill test, bicycle ergometry) can detect myocardial ischemia, which may be the cause of deviations in the electrical axis.
3. Daily ECG monitoring in the event that not only an axis deviation is detected, but also the presence of a rhythm not from the sinus node, that is, rhythm disturbances occur.
4. Chest X-ray - with severe myocardial hypertrophy, an expansion of the cardiac shadow is characteristic.
5. Coronary angiography (CAG) is performed to clarify the nature of lesions of the coronary arteries in coronary artery disease.

Treatment

Direct deviation of the electrical axis does not require treatment, since it is not a disease, but a criterion by which it can be assumed that the patient has one or another cardiac pathology. If, after further examination, some disease is identified, it is necessary to begin treatment as soon as possible.

In conclusion, it should be noted that if the patient sees in the ECG conclusion a phrase that the electrical axis of the heart is not in a normal position, this should alert him and prompt him to consult a doctor to find out the cause of such an ECG sign, even if there are no symptoms does not arise.

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When the EOS is in a vertical position, the S wave is most pronounced in leads I and aVL. ECG in children aged 7–15 years. Characterized by respiratory arrhythmia, heart rate 65-90 per minute. The position of the EOS is normal or vertical.

Regular sinus rhythm - this phrase means an absolutely normal heart rhythm, which is generated in the sinus node (the main source of cardiac electrical potentials).

Left ventricular hypertrophy (LVH) is a thickening of the wall and/or enlargement of the left ventricle of the heart. All five position options (normal, horizontal, semi-horizontal, vertical and semi-vertical) occur in healthy people and are not pathological.

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

The definition of “rotation of the electrical axis of the heart around an axis” may well be found in descriptions of electrocardiograms and is not something dangerous.

The situation should be alarming when, with a pre-existing position of the EOS, its sharp deviation on the ECG occurs. In this case, the deviation most likely indicates the occurrence of a blockade. 6.1. P wave. Analysis of the P wave involves determining its amplitude, width (duration), shape, direction and degree of severity in various leads.

The always negative wave vector P is projected onto the positive parts of most leads (but not all!).

6.4.2. The degree of severity of the Q wave in various leads.

Methods for determining the position of the EOS.

To put it simply, an ECG is a dynamic recording of the electrical charge that makes our heart work (that is, contract). The designations of these graphs (they are also called leads) - I, II, III, aVR, aVL, aVF, V1-V6 - can be seen on the electrocardiogram.

ECG is a completely painless and safe research, it is performed on adults, children and even pregnant women.

Heart rate is not a disease or a diagnosis, but just an abbreviation for “heart rate,” which refers to the number of contractions of the heart muscle per minute. When the heart rate increases above 91 beats/min, they speak of tachycardia; if the heart rate is 59 beats/min or less, this is a sign of bradycardia.

Electrical axis of the heart (EOS): essence, norm of position and violations

Thin people usually have a vertical position of the EOS, while thick people and obese people have a horizontal position. Respiratory arrhythmia is associated with the act of breathing, is normal and does not require treatment.

Requires mandatory treatment. Atrial flutter - this type of arrhythmia is very similar to atrial fibrillation. Sometimes polytopic extrasystoles occur - that is, the impulses that cause them come from various parts of the heart.

Extrasystoles can be called the most common ECG finding; moreover, not all extrasystoles are a sign of the disease. In this case, treatment is necessary. Atrioventricular block, A-V (A-V) block - a violation of the conduction of impulses from the atria to the ventricles of the heart.

Block of the branches (left, right, left and right) of the His bundle (RBBB, LBBB), complete, incomplete, is a violation of the conduction of an impulse through the conduction system in the thickness of the ventricular myocardium.

The most common reasons hypertrophies are arterial hypertension, heart defects and hypertrophic cardiomyopathy. In some cases, next to the conclusion about the presence of hypertrophy, the doctor indicates “with overload” or “with signs of overload.”

Variants of the position of the electrical axis of the heart in healthy people

Cicatricial changes, scars are signs of a myocardial infarction once suffered. In such a situation, the doctor prescribes treatment aimed at preventing a recurrent heart attack and eliminating the cause of circulatory problems in the heart muscle (atherosclerosis).

Timely detection and treatment of this pathology is necessary. Normal ECG in children aged 1 – 12 months. Typically, heart rate fluctuations depend on the child’s behavior (increased frequency when crying, restlessness). At the same time, over the past 20 years there has been a clear trend towards an increase in the prevalence of this pathology.

When can the position of the EOS indicate heart disease?

The direction of the electrical axis of the heart shows the total magnitude of bioelectric changes occurring in the heart muscle with each contraction. The heart is a three-dimensional organ, and in order to calculate the direction of the EOS, cardiologists represent the chest as a coordinate system.

If you project the electrodes onto a conventional coordinate system, you can also calculate the angle of the electrical axis, which will be located where the electrical processes are strongest. The conduction system of the heart consists of sections of the heart muscle consisting of so-called atypical muscle fibers.

Normal ECG readings

Myocardial contraction begins with the appearance of an electrical impulse in the sinus node (which is why the correct rhythm of a healthy heart is called sinus). The myocardial conduction system is a powerful source of electrical impulses, which means that electrical changes that precede cardiac contraction occur in it first of all in the heart.

Rotations of the heart around the longitudinal axis help determine the position of the organ in space and, in some cases, are an additional parameter in diagnosing diseases. The position of the EOS itself is not a diagnosis.

These defects can be either congenital or acquired. The most common acquired heart defects are a consequence of rheumatic fever.

In this case, consultation is necessary sports doctor highly qualified to resolve the issue of the possibility of continuing sports activities.

A shift in the electrical axis of the heart to the right may indicate right ventricular hypertrophy (RVH). Blood from the right ventricle enters the lungs, where it is enriched with oxygen.

As in the case of the left ventricle, RVH is caused by coronary heart disease, chronic heart failure and cardiomyopathies.

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Department of Medical Cybernetics and Informatics RNRMU named after N.I. Pirogov

Work on the section Using the capabilities of a word processor to process and present medical information

The work was carried out by a student of group 243 Mikhailovskaya Ekaterina Aleksandrovna

MOSCOW 2014

General information about ECG

An ECG is a recording of the potential difference between two electrodes located on the surface of the body. The combination of two such electrodes is called an electrocardiographic lead, and an imaginary straight line connecting the two electrodes is called the axis of this lead. Leads can be bipolar or unipolar. In bipolar leads, the potential changes under both electrodes. In unipolar leads, the potential changes under one (active) electrode, but not under the second (indifferent) electrode.

To record an ECG, an indifferent electrode is obtained by combining together the electrodes from the left arm, right arm and left leg; This is the so-called zero electrode (combined electrode, central terminal).

ECG leads.

Typically 12 leads are used. They are combined into two groups:

six limb leads (their axes lie in the frontal plane)

six chest leads (axis - in the horizontal plane).

Limb leads.

The limb leads are divided into three bipolar (standard leads I, II and III) and three unipolar (enhanced leads aVR, aVL and aVF).

In standard leads, electrodes are applied as follows: I - left hand and right hand, II - left leg and right hand, III - left leg and left hand.

In amplified leads, the active electrode is placed: for lead aVR - on the right hand (R - right), for lead aVL - on the left hand (L - left), for lead aVF - on the left leg (F - foot). The letter “V” in the names of these leads means that they measure the potential values ​​(Foliage) under the active electrode, the letter “a” means that this potential is enhanced (Augmented).

Strengthening is achieved by excluding from the null electrode the electrode that is applied to the limb under study (for example, in lead aVF, the null electrode is the combined electrode from the right hand and left hand).

On right leg A grounding electrode is always applied.

Chest leads.

To obtain unipolar chest leads, electrodes are installed at the following points:

• fourth intercostal space along the right edge of the sternum,

• fourth intercostal space on the left edge of the sternum,

• between V2 and V4,

• fifth intercostal space along the left midclavicular line;

• at the same vertical level as V4, but, respectively, along the anterior and midaxillary line.

The indifferent electrode is the usual zero electrode.

The ECG in each lead is a projection of the total vector onto the axis of this lead. Thus, different leads allow us to look at the electrical processes in the heart from different angles. The twelve ECG leads together create a three-dimensional picture of the heart's electrical activity; in addition to them, additional leads are sometimes used. Thus, to diagnose right ventricular infarction, right chest leads V3R, V4R and others are used. Esophageal leads allow us to detect changes in the electrical activity of the atria that are not visible on a conventional ECG.

For telemetric ECG monitoring, one is usually used, and for Holter monitoring, two modified leads are usually used.

Lead meaning

Why were so many leads invented? The EMF of the heart is the vector of the EMF of the heart in the three-dimensional world (length, width, height) taking into account time. On a flat ECG film we can see only 2-dimensional values, so the cardiograph records the projection of the EMF of the heart on one of the planes in time.

Body planes used in anatomy.

Each lead records its own projection of the cardiac EMF. The first 6 leads (3 standard and 3 enhanced from the limbs) reflect the EMF of the heart in the so-called frontal plane and allow you to calculate the electrical axis of the heart with an accuracy of 30° (180° / 6 leads = 30°). The missing 6 leads to form a circle (360°) are obtained by continuing the existing lead axes through the center to the second half of the circle.

6 chest leads reflect the EMF of the heart in the horizontal (transverse) plane (it divides the human body into upper and lower halves). This makes it possible to clarify the localization of the pathological focus (for example, myocardial infarction): interventricular septum, apex of the heart, lateral parts of the left ventricle, etc.

 Electrical axis of the heart (EOS)

If we draw a circle and draw lines through its center corresponding to the directions of the three standard and three enhanced limb leads, we obtain a 6-axis coordinate system. When recording an ECG in these 6 leads, 6 projections of the total EMF of the heart are recorded, from which the location of the pathological focus and the electrical axis of the heart can be assessed.

The electrical axis of the heart is the projection of the total electrical vector of the ECG QRS complex (it reflects the excitation of the ventricles of the heart) onto the frontal plane. Quantitatively, the electrical axis of the heart is expressed by the angle α between the axis itself and the positive (right) half of the axis I of the standard lead, located horizontally.

The rules for determining the position of the EOS in the frontal plane are as follows: the electrical axis of the heart coincides with the one of the first 6 leads in which the highest positive teeth are recorded, and is perpendicular to the lead in which the size of the positive teeth is equal to the size of the negative teeth. Two examples of determining the electrical axis of the heart are given at the end of the article.

Variants of the position of the electrical axis of the heart:

normal: 30° > α< 69°,

vertical: 70° > α< 90°,

horizontal: 0° > α< 29°,

sharp axis deviation to the right: 91° > α< ±180°,

sharp axis deviation to the left: 0° > α< −90°.

Normally, the electrical axis of the heart approximately corresponds to its anatomical axis (y skinny people is directed more vertically from the average values, and in obese people - more horizontally). For example, with hypertrophy (growth) of the right ventricle, the heart axis deviates to the right. With conduction disturbances, the electrical axis of the heart may deviate sharply to the left or right, which in itself is diagnostic sign. For example, with a complete block of the anterior branch of the left bundle branch, a sharp deviation of the electrical axis of the heart to the left (α ≤ −30°) is observed, and a sharp deviation of the posterior branch to the right (α ≥ +120°).

Complete block of the anterior branch of the left bundle branch. The EOS is sharply deviated to the left (α ≅− 30°), because the highest positive waves are visible in aVL, and the equality of the waves is noted in lead II, which is perpendicular to aVL.

Complete block of the posterior branch of the left bundle branch. The EOS is sharply deviated to the right (α ≅+120°), because The tallest positive waves are seen in lead III, and the equality of the waves is noted in lead aVR, which is perpendicular to III.

Waves in ECG

Any ECG consists of waves, segments and intervals.

Waves are convex and concave areas on an electrocardiogram. The following waves are distinguished on the ECG:

P (atrial contraction),

Q, R, S (all 3 teeth characterize ventricular contraction),

T (ventricular relaxation),

U (non-permanent wave, rarely recorded).

A segment on an ECG is a segment of a straight line (isoline) between two adjacent teeth. Highest value have segments 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.

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

P-Wines

Normally, the excitation wave propagates from the sinus node through the myocardium of the right and then the left atrium, and the total vector of atrial depolarization is directed predominantly down and to the left. Because it faces the positive pole of lead II and the negative pole of lead aVR, the P wave is normally positive in lead II and negative in lead aVR.

With retrograde excitation of the atria (inferior atrial or AV nodal rhythm), the opposite picture is observed.

QRS-Complex

Normally, the excitation wave quickly spreads through the ventricles. This process can be divided into two phases, each of which is characterized by a certain predominant direction of the total vector. First, depolarization of the interventricular septum occurs from left to right (vector 1), and then depolarization of the left and right ventricles (vector 2). Since the depolarization wave covers the thick left ventricle for a longer time than the thin right ventricle, vector 2 is directed to the left and backward. In the right chest leads, this two-phase process is reflected by a small positive wave (septal r wave) and a deep S wave, and in the left chest leads (for example, in V6) - by a small negative wave (septal q wave) and a large R wave. In leads V2-V5, the amplitude of the R wave gradually increases, the S- wave decreases. The lead in which the amplitudes of the R and S waves are approximately equal (usually V3 or V4) is called the transition zone.

In healthy people, the shape of the QRS complex in the limb leads varies significantly depending on the position of the electrical axis of the heart (the predominant, or more precisely, the time-averaged direction of the total vector of ventricular depolarization in the frontal plane). The normal position of the electrical axis of the heart is from -30* to +100*; in all other cases, they speak of axis deviation to the left or right.

Deviation of the electrical axis of the heart to the left can be a normal variant, but is more often caused by left ventricular hypertrophy, blockade of the anterior branch of the left bundle branch, and inferior myocardial infarction.

Deviation of the electrical axis of the heart to the right also occurs normally (especially in children and young people), with right ventricular hypertrophy, infarction of the lateral wall of the left ventricle, dextrocardia, left-sided pneumothorax, and blockade of the posterior branch of the left bundle branch.

A false impression of electrical axis deviation can occur if the electrodes are applied incorrectly.

T-waves

Normally, the T wave is directed in the same direction as the QRS complex (concordant with the QRS complex). This means that the predominant direction of the ventricular repolarization vector is the same as the vector of their depolarization. Considering that depolarization and repolarization are opposite electrical processes, the unidirectionality of the T wave of the QRS complex can only be explained by the fact that repolarization moves in the direction opposite to the depolarization wave (that is, from the epicardial endocardium and from the apex to the base of the heart).

U-Prongs

The U wave is normally a small rounded wave (less than or equal to 0.1 mV) that follows the Ti wave and has the same direction. An increase in U wave amplitude is most often caused by medicines(quinidine, procainamide, disopyramide) and hypokalemia.

Tall U waves indicate an increased risk of torsade de pointes. Negative U waves in precordial leads - always pathological sign; it may serve as the first manifestation of myocardial ischemia.

ECG analysis

General scheme of ECG decoding

ECG interpretation

Checking the correct ECG registration

At the beginning of each ECG tape there must be a calibration signal - the 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 on the tape. 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, this is called reduced ECG voltage, which occurs in some pathological conditions.

Heart rate and conduction analysis:

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 spread of the duration of individual R-R intervals is allowed no more than ± 10% of their average duration. If the rhythm is sinus, it is usually regular.

heart rate counting (HR)

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

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

On the overlying ECG interval R-R is equal to 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 is 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, the maximum and minimum heart rate is usually calculated according to the duration of the smallest and largest R-R interval respectively.

determination of the excitation source

In other words, they are looking for where the pacemaker is located, which causes contractions of the atria and ventricles. Sometimes this is one of the most difficult stages, because various disorders of excitability and conduction can be very confusingly combined, which can lead to incorrect diagnosis and improper treatment. To correctly determine the source of excitation on an ECG, you need to have a good knowledge of the conduction system of the heart.

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.

Atrial P wave analysis.

Normally, in leads I, II, aVF, V2 - V6, the P wave is 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 hypertrophy of the right atrium, for example, with “cor pulmonale”.

Split with 2 apexes, widened P wave in leads I, aVL, V5, V6 is characteristic of left atrium hypertrophy, for example, with mitral valve defects.

P-Q interval: normal 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).

There are 3 degrees of AV block:

I degree - P-Q interval is enlarged, but each P wave corresponds to its own QRS complex (there is 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.

Analysis of the ventricular QRST complex:

analysis of the QRS complex.

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 of the height of the R wave, 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 (while the rV1 wave 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), a “transition zone” is usually recorded (equality of the R and S waves).

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 transition point of the QRS complex to the S-T segment is called 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.

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 TI > TIII, and TV6 > TV1. In aVR the T wave is always negative.

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 a small U wave is recorded, which is formed due to short-term increased excitability of the ventricular myocardium after their repolarization.

Electrocardiographic report.

Should include:

Source of rhythm (sinus or not).

Regularity of rhythm (correct or not). Usually sinus rhythm is normal, although respiratory arrhythmia is possible.

Position of the electrical axis of the heart.

Presence of 4 syndromes:

• rhythm disturbance

  conduction disturbance

  hypertrophy and/or overload of the ventricles and atria

  myocardial damage (ischemia, dystrophy, necrosis, scars)

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Axis location

In a healthy person, the left ventricle has a larger mass than the right.

This means that stronger electrical processes occur in the left ventricle, and accordingly the electrical axis is directed there.

If we denote this in degrees, then the LV is in the region of 30-700 with a value of +. This is considered the standard, but it should be said that not everyone has this axis arrangement.

There may be a deviation greater than 0-900 with a value of +, since it is necessary to take into account the individual characteristics of each person’s body.

The doctor may make the following conclusion:

• no deviations;
• semi-vertical position;
• semi-horizontal position.

All these conclusions are the norm.

Concerning individual characteristics, then they note that in people who are tall and have a thin build, the EOS is in a semi-vertical position, and in people who are shorter and have a stocky build, the EOS is in a semi-horizontal position.

The pathological condition looks like a sharp deviation to the left or right.

Reasons for rejection

When the EOS deviates sharply to the left, this may mean that there are certain diseases, namely LV hypertrophy.

In this condition, the cavity stretches and increases in size. Sometimes this occurs due to overload, but it can also be a consequence of a disease.

Diseases that cause hypertrophy are:

In addition to hypertrophy, the main causes of axis deviation to the left are conduction disorders inside the ventricles and during blockades of various types.

Quite often, with such a deviation, blockade of the left leg of His, namely its anterior branch, is diagnosed.

As for the pathological deviation of the heart axis sharply to the right, this may mean that there is RV hypertrophy.

This pathology can be caused by the following diseases:

As well as diseases characteristic of LV hypertrophy:

• cardiac ischemia;
• chronic heart failure;
• cardiomyopathy;
• complete blockade of the left leg of His (posterior branch).

When the electrical axis of the heart is sharply deviated to the right in a newborn, this is considered normal.

We can conclude that the main cause of pathological displacement to the left or right is ventricular hypertrophy.

And the greater the degree of this pathology, the more EOS is rejected. A change in the axis is simply an ECG sign of some disease.

It is important to carry out timely identification of these indications and diseases.

Deviation of the heart axis does not cause any symptoms; symptoms manifest themselves from hypertrophy, which disrupts the hemodynamics of the heart. The main symptoms are headaches, chest pain, swelling of the limbs and face, suffocation and shortness of breath.

If cardiac symptoms occur, you should immediately undergo electrocardiography.

Determination of ECG signs

Legal form. This is the position at which the axis is within the range of 70-900.

On the ECG this is expressed as tall R waves in the QRS complex. In this case, the R wave in lead III exceeds the wave in lead II. In lead I there is an RS complex, in which S has a greater depth than the height of R.

Levogram. In this case, the position of the alpha angle is within the range of 0-500. The ECG shows that in standard lead I the QRS complex is expressed as R-type, and in lead III its form is S-type. The S wave has a depth greater than the height R.

With blockade of the posterior branch of the left leg of His, the alpha angle has a value greater than 900. On the ECG, the duration of the QRS complex may be slightly increased. There is a deep S wave (aVL, V6) and a high R wave (III, aVF).

With blockade of the anterior branch of the left leg of His, the values ​​will be from -300 or more. On ECG signs These are the late R wave (lead aVR). Leads V1 and V2 may have a small r wave. In this case, the QRS complex is not expanded, and the amplitude of its waves is not changed.

Blockade of the anterior and posterior branches of the left leg of His (complete block) - in this case, the electrical axis is sharply deviated to the left and can be located horizontally. On the ECG in the QRS complex (leads I, aVL, V5, V6), the R wave is widened and its apex is jagged. Near the high R wave there is a negative T wave.

It should be concluded that the electrical axis of the heart can be moderately deviated. If the deviation is sharp, then this may mean the presence of serious cardiac diseases.

Determination of these diseases begins with an ECG, and then methods such as echocardiography, radiography, and coronary angiography are prescribed. An ECG with stress and 24-hour Holter monitoring can also be performed.

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How is an electrocardiogram taken?

ECG recording is performed in a special room, maximally shielded from various electrical interference. The patient sits comfortably on the couch with a pillow under his head. To take an ECG, electrodes are applied (4 on the limbs and 6 on the chest). An electrocardiogram is recorded during quiet breathing. In this case, the frequency and regularity of heart contractions, the position of the electrical axis of the heart and some other parameters are recorded. This simple method allows you to determine whether there are abnormalities in the functioning of the organ, and, if necessary, refer the patient for a consultation with a cardiologist.

What influences the location of the EOS?

Before discussing the direction of the electrical axis, you should understand what the conduction system of the heart is. It is this structure that is responsible for the passage of impulses through the myocardium. The conduction system of the heart is atypical muscle fibers that connect different parts of the organ. It begins with the sinus node, located between the mouths of the vena cava. Next, the impulse is transmitted to the atrioventricular node, located in the lower part of the right atrium. The next to take the baton is the His bundle, which quickly diverges into two legs - left and right. In the ventricle, the branches of the His bundle immediately become Purkinje fibers, which penetrate the entire cardiac muscle.

An impulse entering the heart cannot escape the myocardial conduction system. This is a complex structure with fine settings, sensitively responding to the slightest changes in the body. In case of any disturbances in the conduction system, the electrical axis of the heart can change its position, which will be immediately recorded on the electrocardiogram.

EOS location options

As you know, the human heart consists of two atria and two ventricles. Two circles of blood circulation (large and small) ensure the normal functioning of all organs and systems. Normally, the mass of the myocardium of the left ventricle is slightly greater than that of the right. It turns out that all impulses passing through the left ventricle will be somewhat stronger, and the electrical axis of the heart will be oriented specifically towards it.

If you mentally transfer the position of the organ to a three-dimensional coordinate system, it will become clear that the EOS will be located at an angle from +30 to +70 degrees. Most often, these are the values ​​recorded on the ECG. The electrical axis of the heart can also be located in the range from 0 to +90 degrees, and this, too, according to cardiologists, is the norm. Why do such differences exist?

Normal location of the electrical axis of the heart

There are three main provisions of the EOS. The range from +30 to +70° is considered normal. This option occurs in the vast majority of patients who visit a cardiologist. The vertical electrical axis of the heart is found in thin, asthenic people. In this case, the angle values ​​will range from +70 to +90°. The horizontal electrical axis of the heart is found in short, tightly built patients. On their card, the doctor will mark the EOS angle from 0 to +30°. Each of these options is normal and does not require any correction.

Pathological location of the electrical axis of the heart

A condition in which the electrical axis of the heart is deviated is not a diagnosis in itself. However, such changes in the electrocardiogram may indicate various disorders in the functioning of the important body. The following diseases lead to serious changes in the functioning of the conduction system:

Cardiac ischemia;

Chronic heart failure;

Cardiomyopathies of various origins;

Congenital defects.

Knowing about these pathologies, the cardiologist will be able to notice the problem in time and refer the patient to hospital treatment. In some cases, when EOS deviation is registered, the patient requires emergency care in intensive care.

Deviation of the electrical axis of the heart to the left

Most often, such changes in the ECG are observed with enlargement of the left ventricle. This usually occurs with the progression of heart failure, when the organ simply cannot fully perform its function. It is possible that this condition may develop in arterial hypertension, which is accompanied by pathology of large vessels and increased blood viscosity. In all these conditions, the left ventricle is forced to work hard. Its walls thicken, leading to inevitable disruption of the impulse through the myocardium.

Deviation of the electrical axis of the heart to the left also occurs with narrowing of the aortic mouth. In this case, stenosis of the lumen of the valve located at the exit from the left ventricle occurs. This condition is accompanied by a disruption of normal blood flow. Part of it is retained in the cavity of the left ventricle, causing it to stretch and, as a result, thickening of its walls. All this causes a natural change in EOS as a result of improper conduction of the impulse through the myocardium.

Deviation of the electrical axis of the heart to the right

This condition clearly indicates right ventricular hypertrophy. Similar changes develop in certain respiratory diseases (for example, bronchial asthma or chronic obstructive pulmonary disease). Some congenital heart defects can also cause the right ventricle to become enlarged. First of all, it is worth noting pulmonary artery stenosis. In some situations, tricuspid valve insufficiency can also lead to a similar pathology.

Why is changing EOS dangerous?

Most often, deviations of the electrical axis of the heart are associated with hypertrophy of one or another ventricle. This condition is a sign of a long-standing chronic process and, as a rule, does not require emergency assistance cardiologist. The real danger is the change in the electrical axis due to His bundle block. In this case, the conduction of impulses through the myocardium is disrupted, which means there is a risk of sudden cardiac arrest. This situation requires urgent intervention by a cardiologist and treatment in a specialized hospital.

With the development of this pathology, the EOS can be deviated both to the left and to the right, depending on the localization of the process. The blockade may be caused by myocardial infarction, infectious lesion heart muscle, as well as taking certain medications. A regular electrocardiogram allows you to quickly make a diagnosis, which means it allows the doctor to prescribe treatment taking into account all important factors. In severe cases, it may be necessary to install a pacemaker (pacemaker), which will send impulses directly to the heart muscle and thereby provide normal work organ.

What to do if the EOS is changed?

First of all, it is worth considering that the deviation of the heart axis itself is not the basis for making a particular diagnosis. The position of the EOS can only give impetus to a more careful examination of the patient. For any changes in the electrocardiogram, you cannot do without consulting a cardiologist. An experienced doctor will be able to recognize normal and pathological conditions and, if necessary, prescribe additional examinations. This may be echocardioscopy for targeted study of the condition of the atria and ventricles, monitoring blood pressure and other techniques. In some cases, consultation is required related specialists to decide on further management of the patient.

To summarize, several important points should be highlighted:

The normal EOS value is considered to be the range from +30 to +70°.

Horizontal (from 0 to +30°) and vertical (from +70 to +90°) positions of the heart axis are acceptable values ​​and do not indicate the development of any pathology.

Deviations of the EOS to the left or to the right may indicate various disorders in the conduction system of the heart and require consultation with a specialist.

A change in EOS detected on a cardiogram cannot be made as a diagnosis, but is a reason to visit a cardiologist.

The heart is an amazing organ that ensures the functioning of all systems of the human body. Any changes that occur in it inevitably affect the functioning of the whole organism. Regular examinations by a therapist and an ECG will allow timely detection of serious diseases and avoid the development of any complications in this area.

The resulting vector of all bioelectrical oscillations of the heart muscle is called electric axle. Most often it coincides with the anatomical one. This indicator is used when analyzing ECG data to assess the dominance of one part of the heart, which may be indirect sign myocardial hypertrophy.

Read in this article

Normal electrical axis of the heart

The direction of the heart axis is calculated in degrees. To do this, they use such a concept as the alpha angle. It is formed by a horizontal line that is drawn through the electrical center of the heart. To determine it, the axis of the first ECG lead is shifted to the Einthoven center. This is a triangle, its vertices are the hands spread out to the side and the left foot.

In a healthy person, the electrical axis fluctuates between 30 and 70 degrees. This is due to the fact that the left ventricle is more developed than the right, therefore, more impulses come from it. This position of the heart occurs with a normosthenic physique, and the ECG is called a normogram.

Position deviations

A change in the direction of the heart axis on an electrocardiogram is not always a sign of pathology. Therefore, for making a diagnosis, its deviations are of auxiliary importance and are used for the preliminary formulation of the conclusion.

Right

Pravogramma (alpha 90 - 180) on the ECG occurs with an increase in the mass of the myocardium of the right ventricle. The following diseases lead to this condition:

• chronic obstructive pulmonary diseases;
• bronchitis;
• bronchial asthma;
• narrowing of the pulmonary artery trunk, mitral orifice;
• circulatory failure with congestion in the lungs;
• cessation of the passage of impulses (blockade) of the left Hiss leg;
• thrombosis of pulmonary vessels;
• cirrhosis of the liver.

Left

A left-side shift of the electrical axis (alpha from 0 to minus 90) occurs quite often. Leads to him. This may be due to the following conditions:

How to determine by ECG

In order to identify the position of the axis, it is necessary to examine two leads aVL and aVF. You need to measure the tooth in them R. Normally, its amplitude is equal. If it is high in aVL and absent in aVF, then the position is horizontal; in vertical it will be the other way around.

There will be an axis deviation to the left if R in the first standard lead is greater than S in the third. Pravogram - S1 exceeds R3, and if R2, R1, R3 are arranged in descending order, then this is a sign of a normogram. For a more detailed study, special tables are used.

Additional Research

If the ECG reveals an axis shift to the right or left, then the following additional examination methods are used to clarify the diagnosis:

If there is only a pathological alpha angle, and no other manifestations are detected on the ECG, the patient does not experience difficulty breathing, the pulse and blood pressure are normal, then this condition does not require any further action. This may be due to an anatomical feature.

A more unfavorable sign is pravogramma with lung diseases, as well as levogramma combined with hypertension. In these cases, the displacement of the heart axis can be used to judge the degree of progression of the underlying pathology. If the diagnosis is unknown, and there is a significant axis deviation with cardiac symptoms, then the patient should be fully examined to identify the cause of this phenomenon.

The displacement of the electrical axis can be to the left or to the right, depending on which of the heart ventricles the activity predominates. Such changes in the ECG are an indirect sign of myocardial hypertrophy and are considered in conjunction with other indicators. If there are complaints about heart function, additional examination is required. In children younger age spelling is physiological state, requiring no intervention.

Read also

The detected bundle branch block indicates many abnormalities in the functioning of the myocardium. It can be right and left, complete and incomplete, branches, anterior branch, two- and three-bundle. Why is blockade dangerous in adults and children? What are the ECG signs and treatment? What are the symptoms in women? Why was it detected during pregnancy? Is bundle block block dangerous?

The electrical axis of the heart (EOS) is one of the main parameters of the electrocardiogram. This term is actively used in cardiology and in functional diagnostics, reflecting the processes occurring in the most important organ of the human body.

The position of the electrical axis of the heart shows the specialist what exactly is happening in the heart muscle every minute. This parameter is the sum of all bioelectrical changes that are observed in the organ. When taking an ECG, each electrode of the system registers excitation passing at a strictly defined point. If you transfer these values ​​to a conventional three-dimensional coordinate system, you can understand how the electrical axis of the heart is located and calculate its angle relative to the organ itself.

How is an electrocardiogram taken?

ECG recording is carried out in a special room, maximally shielded from various electrical interference. The patient sits comfortably on the couch with a pillow under his head. To take an ECG, electrodes are applied (4 on the limbs and 6 on the chest). An electrocardiogram is recorded during quiet breathing. In this case, the frequency and regularity of heart contractions, the position of the electrical axis of the heart and some other parameters are recorded. This simple method allows you to determine whether there are abnormalities in the functioning of the organ, and, if necessary, refer the patient for a consultation with a cardiologist.

What influences the location of the EOS?

Before discussing the direction of the electrical axis, you should understand what the conduction system of the heart is. It is this structure that is responsible for the passage of impulses through the myocardium. The conduction system of the heart is atypical muscle fibers that connect different parts of the organ. It begins from the sinus node, located between the mouths of the vena cava. Next, the impulse is transmitted to the atrioventricular node, located in the lower part of the right atrium. The next to take the baton is the His bundle, which quite quickly diverges into two legs - left and right. In the ventricle, the branches of the His bundle immediately become Purkinje fibers, which penetrate the entire cardiac muscle.

An impulse entering the heart cannot be avoided by the myocardial conduction system. This is a complex structure with fine settings, sensitively reacts to the slightest changes in the body. In case of any disturbances in the conduction system, the electrical axis of the heart can change its position, which will be immediately recorded on the electrocardiogram.

EOS location options

As you know, the human heart consists of two atria and two ventricles. Two circles of blood circulation (large and small) ensure the normal functioning of all organs and systems. Normally, the mass of the myocardium of the left ventricle is greater than that of the right. It turns out that all impulses passing through the left ventricle will be somewhat stronger, and the electrical axis of the heart is oriented specifically towards it.

If you mentally transfer the positions of the organ to a three-dimensional coordinate system, it will become clear that the EOS will be located at an angle from +30 to +70 degrees. Most often, these are the values ​​recorded on the ECG. The electrical axis of the heart can be located in the range from 0 to +90 degrees, and this, too, according to cardiologists, is the norm. Why do such differences exist?

Normal location of the electrical axis of the heart

There are three main provisions of the EOS. The range from +30 to +70° is considered normal. This option occurs in the vast majority of patients who visit a cardiologist. The vertical electrical axis of the heart is found in thin, asthenic people. In this case, the angle value will fluctuate from +70 to +90°. The horizontal electrical axis of the heart appears in short, densely built patients. On their card, the doctor will mark the EOS angle from 0 to +30°. Each of these options is normal and does not require any correction.

Pathological location of the electrical axis of the heart

A condition in which the electrical axis of the heart is deviated is not a diagnosis in itself. However, such changes in the electrocardiogram may indicate various disorders in the functioning of the most important organ. The following diseases lead to serious changes in the functioning of the conduction system:

Cardiac ischemia;

Chronic heart failure;

Cardiomyopathies of various origins;

Congenital defects.

Knowing about these pathologies, the cardiologist will be able to notice the problem in time and refer the patient for inpatient treatment. In some cases, when EOS deviation is registered, the patient needs emergency care in intensive care.

Deviation of the electrical axis of the heart to the left

Most often, such changes in the ECG are observed with enlargement of the left ventricle. This usually occurs with the progression of heart failure, when the organ simply cannot fully perform its function. It is possible that the development of such a condition, with arterial hypertension, is accompanied by pathology of large vessels and an increase in blood viscosity. In all these conditions, the left ventricle is forced to work hard. Its walls thicken, leading to inevitable disruption of the impulse through the myocardium.

Deviation of the electrical axis of the heart to the left also occurs with narrowing of the aortic mouth. In this case, stenosis of the lumen of the valve located at the exit from the left ventricle occurs. This condition is accompanied by a disruption of normal blood flow. Part of it is retained in the cavity of the left ventricle, causing it to stretch and, as a result, thickening of its walls. All this causes a natural change in EOS as a result of improper conduction of the impulse through the myocardium.

Deviation of the electrical axis of the heart to the right

This situation clearly indicates right ventricular hypertrophy. Similar changes develop in certain respiratory diseases (for example, bronchial asthma or chronic obstructive pulmonary disease). Some congenital heart defects can cause the right ventricle to become enlarged. First of all, it is worth noting pulmonary artery stenosis. In some situations, tricuspid valve insufficiency can also lead to this pathology.

Why is changing EOS dangerous?

Most often, deviation of the electrical axis of the heart is associated with hypertrophy of one or another ventricle. This condition is a sign of a long-standing chronic process and, as a rule, does not require emergency help from a cardiologist. The real danger is the change in the electrical axis due to His bundle block. In this case, the conduction of impulses through the myocardium is disrupted, which means there is a risk of sudden cardiac arrest. This situation requires urgent intervention by a cardiologist and treatment in a specialized hospital.

With the development of this pathology, EOS can be deviated both on the left and on the right, depending on the localization of the process. The blockade can be caused by myocardial infarction, infection of the heart muscle, as well as taking certain medications. A regular electrocardiogram allows you to quickly make a diagnosis, and therefore enable the doctor to prescribe treatment, taking into account all important factors. In severe cases, it may be necessary to install a pacemaker (pacemaker), which will send impulses directly to the heart muscle and thereby ensure normal functioning of the organ.

What to do if the EOS is changed?

First of all, it is worth considering that the deviation of the heart axis itself is not the basis for making a particular diagnosis. The position of the EOS can only give impetus to a more careful examination of the patient. For any changes in the electrocardiogram, you cannot do without consulting a cardiologist. An experienced doctor will be able to recognize normal and pathological conditions and, if necessary, prescribe additional examinations. This may include echocardioscopy for targeted study of the condition of the atria and ventricles, blood pressure monitoring and other techniques. In some cases, consultation with related specialists is required to decide on the further management of the patient.

To summarize, several important points should be highlighted:

The normal EOS value is considered to be the range from +30 to +70°.

Horizontal (from 0 to +30°) and vertical (from +70 to +90°) position of the heart axis are acceptable values ​​and do not indicate the development of any pathology.

Deviation of the EOS to the left or to the right may indicate various disorders in the conduction system of the heart and require specialist consultation.

A change in EOS detected on a cardiogram cannot be used as a diagnosis, but is a reason to visit a cardiologist.

The heart is an amazing organ that ensures the functioning of all systems of the human body. Any changes that occur in it inevitably affect the functioning of the whole organism. Regular examinations by a therapist and ECG will allow you to detect the emergence of serious diseases in time and avoid the development of any complications in this area.