What is the electrical axis of the heart and what are the consequences of deviations from the norm? Deviation of the electrical axis.

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

The electrical axis of the heart (EOS) is a term used in cardiology and functional diagnostics, reflecting the electrical processes occurring in the heart.

Direction electrical axis heart shows the total amount of bioelectrical 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.

Each electrode, when removed, registers the bioelectrical excitation that occurs in a certain area of the myocardium. If we project the electrodes onto a conditional coordinate system, then we can also calculate the angle of the electric axis, which will be located where the electrical processes are strongest.

The conduction system of the heart and why is it important to determine the EOS?

The conduction system of the heart is a section of the heart muscle, consisting of the so-called atypical muscle fibers. These fibers are well innervated and provide synchronous contraction of the organ.

Myocardial contraction begins with the appearance of an electrical impulse in the sinus node (which is why the correct rhythm healthy heart called sinus). From the sinus node, the electrical excitation impulse passes to the atrioventricular node and further along the bundle of His. This bundle passes in the interventricular septum, where it is divided into the right, heading to the right ventricle, and the left legs. The left leg of the bundle of His is divided into two branches, anterior and posterior. The anterior branch is located in the anterior sections of the interventricular septum, in the anterolateral wall of the left ventricle. The posterior branch of the left leg of the bundle of His is located in the middle and lower third of the interventricular septum, the posterolateral and lower wall of the left ventricle. We can say that the back branch is somewhat to the left of the front.

The conduction system of the myocardium is a powerful source of electrical impulses, which means that electrical changes occur in it first of all in the heart, preceding heart contraction. With violations in this system, the electrical axis of the heart can significantly change its position., which will be discussed next.

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

The mass of the cardiac muscle of the left ventricle is normally much greater than the mass of the right ventricle. Thus, the electrical processes occurring in the left ventricle are stronger in total, and the EOS will be directed specifically to it. If we project the position of the heart on the coordinate system, then the left ventricle will be in the region of +30 + 70 degrees. This will be the normal position of the axis. However, depending on individual anatomical features and physique the position of the EOS in healthy people ranges from 0 to +90 degrees:

So, vertical position EOS will be considered in the range from + 70 to + 90 degrees. This position of the axis of the heart is found in tall, thin people- asthenics.
Horizontal position of the EOS more common in short, stocky people with a wide chest - hypersthenics, and its value ranges from 0 to + 30 degrees.

The structural features for each person are very individual, there are practically no pure asthenics or hypersthenics, more often these are intermediate body types, therefore the electric axis can also have an intermediate value (semi-horizontal and semi-vertical).

All five positions (normal, horizontal, semi-horizontal, vertical and semi-vertical) are found in healthy people and are not pathological.

So, in the conclusion of an ECG in an absolutely healthy person, it can be said: "EOS vertical, sinus rhythm, heart rate - 78 per minute", which is a variant of the norm.

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 the diagnosis of diseases.

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

When the position of the EOS can talk about heart disease?

In itself, the position of the EOS is not a diagnosis. However There are a number of diseases in which there is a displacement of the axis of the heart. Significant changes in the position of the EOS lead to:

various genesis(especially dilated cardiomyopathy).

EOS deviations to the left

So, the deviation of the electrical axis of the heart to the left may indicate (LVH), i.e. its increase in size, which is also not an independent disease, but may indicate an overload of the left ventricle. This condition often occurs with a long-term current and is associated with significant vascular resistance to blood flow, as a result of which the left ventricle must contract with greater force, the mass of the muscles of the ventricle increases, which leads to its hypertrophy. Ischemic disease, chronic heart failure, cardiomyopathies also cause left ventricular hypertrophy.

hypertrophic changes in the myocardium of the left ventricle - the most common cause of EOS deviation to the left

In addition, LVH develops when the valvular apparatus of the left ventricle is damaged. This condition leads to stenosis of the aortic mouth, in which the ejection of blood from the left ventricle is difficult, insufficiency aortic valve when part of the blood returns to the left ventricle, overloading it with volume.

These defects can be either congenital or acquired. The most commonly acquired heart defects are the result of a transferred one. Left ventricular hypertrophy is found in professional athletes. In this case, it is necessary to consult a highly qualified sports doctor to decide whether it is possible to continue playing sports.

Also, the EOS is deflected to the left at and different. E-mail deviation the axis of the heart to the left, along with a number of other ECG signs, is one of the indicators of the blockade of the anterior branch of the left leg of the bundle of His.

EOS deviations to the right

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. chronic diseases respiratory organs, accompanied, such as bronchial asthma, chronic obstructive pulmonary disease with a long course, cause hypertrophy. Stenosis leads to right ventricular hypertrophy pulmonary artery and tricuspid valve insufficiency. As in the case of the left ventricle, RVH is caused ischemic disease heart disease, chronic heart failure and cardiomyopathies. Deviation of the EOS to the right occurs with a complete blockade of the posterior branch of the left leg of the bundle of His.

What to do if an EOS shift is found on the cardiogram?

None of the above diagnoses can be made on the basis of EOS displacement alone. The position of the axis serves only as an additional indicator in the diagnosis of a particular disease. If the axis of the heart deviates beyond normal values (from 0 to +90 degrees), a consultation with a cardiologist and a series of studies is necessary.

But still The main cause of EOS displacement is myocardial hypertrophy. The diagnosis of hypertrophy of one or another part of the heart can be made according to the results. Any disease that leads to a displacement of the axis of the heart is accompanied by a number of clinical signs and requires further investigation. The situation should be alarming when, in the pre-existing position of the EOS, its sharp deviation on the ECG. In this case, the deviation most likely indicates the occurrence of a blockade.

By itself, the displacement of the electrical axis of the heart does not need treatment, refers to electrocardiological signs and requires, first of all, finding out the cause of the occurrence. Only a cardiologist can determine the need for treatment.

Video: EOS in the course “ECG for everyone”

The average electric axis of the complex QRS- the main measurement required for each electrocardiogram. In most healthy individuals, it is between -30° and +100°. An angle of -30° or more negative is described as left axis deviation, and an angle of +100° or more positive as right axis deviation. In other words, the deviation of the axis to the left is the changed position of the average electrical axis of the complex QRS in people with a horizontal position of the electrical axis of the heart. Deviation of the axis to the right is an altered position of the middle electrical axis of the complex QRS in people with a vertical position of the electrical axis of the heart.

The position of the average electrical axis of the complex QRS depends on the anatomical position of the heart and the direction of impulse propagation through the ventricles (the direction of ventricular depolarization).

Influence of the anatomical position of the heart on the electrical axis of the QRS complex

Confirmed breathing effect. When a person inhales, the diaphragm descends and the heart takes a more vertical position in the chest, which is normal. accompanied by a vertical displacement of the EOS(to the right). In patients with emphysema, an anatomically vertical position of the heart and an electrically vertical mean electrical axis of the complex are usually observed. QRS. On the contrary, when exhaling, the diaphragm rises and the heart takes a more horizontal position in the chest, which is usually accompanied by a horizontal displacement of the EOS(left).

Influence of the direction of ventricular depolarization

It can be confirmed with incomplete blockade of the anterior branch of the LBBB, when the propagation of impulses along the upper left ventricle is disturbed and the average electrical axis of the complex QRS deviated to the left (see section "Violation of intraventricular conduction"). On the contrary, with hypertrophy of the pancreas, it is deviated to the right.

How to recognize EOS deviation to the right and left

Right axis deviation

It is revealed if the average electric axis of the complex QRS is +100° or more. Remember that with high teeth R equal amplitude in leads II and III, the angle of the axis should be +90°. Approximate Rule indicates a deviation of the axis to the right, if there are high teeth in the II, III leads R, and the tooth R in lead III exceeds the tooth R in lead II. In addition, a complex is formed in lead I RS-type, where the depth of the tooth S more height prong R(see fig. 5-8; 5-9).

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The conduction system of the heart and why is it important to determine the EOS?

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). From the sinus node, the electrical excitation impulse passes to the atrioventricular node and further along the bundle of His. This bundle passes in the interventricular septum, where it is divided into the right, heading to the right ventricle, and the left legs. The left leg of the bundle of His is divided into two branches, anterior and posterior. The anterior branch is located in the anterior sections of the interventricular septum, in the anterolateral wall of the left ventricle. The posterior branch of the left leg of the bundle of His is located in the middle and lower third of the interventricular septum, the posterolateral and lower wall of the left ventricle. We can say that the back branch is somewhat to the left of the front.

The conduction system of the myocardium 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. With violations in this system, the electrical axis of the heart can significantly change its position., which will be discussed next.

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

The mass of the cardiac muscle of the left ventricle is normally much greater than the mass of the right ventricle. Thus, the electrical processes occurring in the left ventricle are stronger in total, and the EOS will be directed specifically to it. If we project the position of the heart on the coordinate system, then the left ventricle will be in the region of +30 + 70 degrees. This will be the normal position of the axis. However, depending on the individual anatomical features and physique the position of the EOS in healthy people ranges from 0 to +90 degrees:

So, vertical position EOS will be considered in the range from + 70 to + 90 degrees. This position of the axis of the heart is found in tall, thin people - asthenics.
Horizontal position of the EOS more common in short, stocky people with a wide chest - hypersthenics, and its value ranges from 0 to + 30 degrees.

All five positions (normal, horizontal, semi-horizontal, vertical and semi-vertical) are found in healthy people and are not pathological.

So, in the conclusion of an ECG in an absolutely healthy person, it can be said: "EOS vertical, sinus rhythm, heart rate - 78 per minute", which is a variant of the norm.

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 the diagnosis of diseases.

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

When the position of the EOS can talk about heart disease?

Cardiac ischemia.
Cardiomyopathy of various origins (especially dilated cardiomyopathy).
Chronic heart failure.
Congenital anomalies of the structure of the heart.

EOS deviations to the left

Thus, the deviation of the electrical axis of the heart to the left may indicate left ventricular hypertrophy (LVH), i.e. its increase in size, which is also not an independent disease, but may indicate an overload of the left ventricle. This condition often occurs with long-term arterial hypertension and is associated with significant vascular resistance to blood flow, as a result of which the left ventricle must contract with greater force, the muscle mass of the ventricle increases, which leads to its hypertrophy. Ischemic disease, chronic heart failure, cardiomyopathies also cause left ventricular hypertrophy.

In addition, LVH develops when the valvular apparatus of the left ventricle is damaged. This condition leads to stenosis of the aortic mouth, in which the ejection of blood from the left ventricle is difficult, aortic valve insufficiency, when part of the blood returns to the left ventricle, overloading it with volume.

These defects can be either congenital or acquired. The most commonly acquired heart defects are the result of rheumatic fever. Left ventricular hypertrophy is found in professional athletes. In this case, it is necessary to consult a highly qualified sports doctor to decide whether it is possible to continue playing sports.

Also, the EOS is deviated to the left with violations of intraventricular conduction and various heart blocks. E-mail deviation the axis of the heart to the left, along with a number of other ECG signs, is one of the indicators of the blockade of the anterior branch of the left leg of the bundle of His.

EOS deviations to the right

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. Chronic diseases of the respiratory system, accompanied by pulmonary hypertension, such as bronchial asthma, chronic obstructive pulmonary disease with a long course cause hypertrophy. Pulmonary artery stenosis and tricuspid valve insufficiency lead to right ventricular hypertrophy. As with the left ventricle, RVH is caused by coronary heart disease, congestive heart failure, and cardiomyopathies. Deviation of the EOS to the right occurs with a complete blockade of the posterior branch of the left leg of the bundle of His.

What to do if an EOS shift is found on the cardiogram?

But still The main cause of EOS displacement is myocardial hypertrophy. The diagnosis of hypertrophy of one or another part of the heart can be made according to the results of ultrasound. Any disease that leads to a displacement of the axis of the heart is accompanied by a number of clinical signs and requires additional examination. The situation should be alarming when, with the pre-existing position of the EOS, its sharp deviation occurs on the ECG. In this case, the deviation most likely indicates the occurrence of a blockade.

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Normal values and causes of violation

The direction of this indicator depends on various physiological and anatomical factors. average rate the position +59 0 is considered. But normogram options fall into a wide range from +20 0 to +100 0.

Healthy Electric Axis shifts to the left at following conditions :

at the moment of deep exhalation;
when changing the position of the body to horizontal - internal organs put pressure on the diaphragm
with a high-standing diaphragm - observed in hypersthenics (short, strong people).

Indicator shift to the right in the absence of pathology observed in such situations:

at the end of a deep breath;
when changing the position of the body to the vertical;
in asthenics (tall, thin people), the vertical position of the EOS is the norm.

Diagnostics on the ECG

An electrocardiogram is the main tool for determining EOS. To detect changes in the location of the axis, use two equivalent ways. The first method is more often used by diagnosticians, the second method is more common among cardiologists and therapists.

Alpha Offset Detection

The value of the alpha angle directly shows the displacement of the EOS in one direction or another. To calculate this angle, find the algebraic sum of the Q, R and S waves in the first and third standard leads. To do this, measure the height of the teeth in millimeters, and when adding, the positive or negative value of a particular tooth is taken into account.

The value of the sum of the teeth from the first lead is found on horizontal axis, and from the third - on the vertical. The intersection of the resulting lines determines the alpha angle.

Visual Definition

A simpler and more visual way to determine the EOS - comparison of R and S waves in the first and third standard leads. If the absolute value of the R wave within one lead is greater than the value of the S wave, then one speaks of an R-type ventricular complex. If vice versa, then the ventricular complex is classified as S-type.

When the EOS deviates to the left, a picture of RI - SIII is observed, which means R-type ventricular complex in the first lead and S-type in the third. If the EOS is deviated to the right, then SI - RIII is determined on the electrocardiogram.

Establishing diagnosis

What does it mean if the electrical axis of the heart is deviated to the left? EOS displacement is not an independent disease. This is a sign of changes in the heart muscle or its conduction system, which lead to the development of the disease. The deviation of the electrical axis to the left indicates such violations:

an increase in the size of the left ventricle - hypertrophy (LVH);
malfunctions of the valves of the left ventricle, due to which the ventricle is overloaded with blood volume;
cardiac blockades, for example, left bundle branch blockade of Hiss (it looks like this on the ECG, which you can learn about from another article);
conduction disturbances within the left ventricle.

Diseases that are accompanied by a levogram

If a patient has an EOS deviation, then this may be due to diseases such as:

ischemic heart disease (CHD);
cardiopathy of various origins;
chronic heart failure (CHF) of the left ventricular type;
birth defects hearts;
myocardial infarction;
myocardial infection.

In addition to diseases, the intake of certain drugs can lead to blockade of the conduction system of the heart. medicines.

Additional Research

The detection on the cardiogram of the EOS deviation to the left side is not in itself the basis for the final conclusion of the doctor. In order to determine what specific changes occur in the heart muscle, additional instrumental studies are required.

Bicycle ergometry(electrocardiogram while walking on a treadmill or on an exercise bike). Test to detect ischemia of the heart muscle.
ultrasound. With the help of ultrasound, the degree of ventricular hypertrophy and violations of their contractile function are assessed.
24-hour Holter ECG monitoring. The cardiogram is removed during the day. Assign in cases of rhythm disturbance, which is accompanied by a deviation of the EOS.
X-ray examination chest. With significant hypertrophy of myocardial tissues, an increase in the cardiac shadow in the picture is observed.
Angiography coronary arteries(KAG). Allows you to determine the degree of damage to the coronary arteries in diagnosed coronary disease.
echocardioscopy. Allows you to purposefully determine the state of the patient's ventricles and atria.

Treatment

Deviation of the electrical axis of the heart to the left of the normal position in itself is not a disease. This is a sign defined by instrumental research, which allows you to identify violations in the work of the heart muscle.

Ischemia, heart failure, and some cardiopathies are treated with drugs. Additional diet and healthy lifestyle life leads to the improvement of the patient's condition.

In severe cases, surgery is required, for example, with congenital or acquired heart defects. If the conduction system is severely damaged, it may be necessary to transplant a pacemaker, which will send signals directly to the myocardium and cause it to contract.

Most often, the deviation is not a threatening symptom. But if the axis changes its position abruptly, reaches values of more than 90 0, this may indicate blockade of the legs of the Hiss bundle and threatens with cardiac arrest. This patient requires urgent hospitalization intensive care. A sharp and pronounced deviation of the electrical axis of the heart to the left looks like this:

Detection of displacement of the electrical axis of the heart is not a cause for concern. But if this symptom is detected, you should immediately consult a doctor for further examination and identify the cause of this condition. Annual scheduled Electrocardiography allows you to timely detect abnormalities in the work of the heart and immediately begin therapy.

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Axis location

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

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

If we indicate 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 axle arrangement.

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

The doctor may conclude:

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

All of these conclusions are the norm.

Concerning individual characteristics, it is noted that people tall and a thin physique, the EOS is in a semi-vertical position, and in people who are lower and at the same time they are stocky, the EOS has 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 state, the cavity is stretched, increases in size. Sometimes this is due to overload, but it can also be the result of a disease.

Diseases that cause hypertrophy are:

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

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

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

This pathology can be caused by such diseases:

As well as diseases characteristic of LV hypertrophy:

ischemia of the heart;
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 the norm.

It can be concluded 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. An axis change is simply an ECG sign of some kind of disease.

It is important to timely determine these indications and diseases.

Deviation of the axis of the heart does not cause any symptoms, the symptomatology manifests itself from hypertrophy, which disrupts the hemodynamics of the heart. The main symptoms are headaches, chest pains, swelling of the extremities and face, suffocation and shortness of breath.

With the manifestation of symptoms of a cardiological nature, you should immediately undergo an electrocardiography.

Definition of ECG signs

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

On the ECG, this is expressed as high R waves in the QRS complex. In this case, the R wave in lead III exceeds the wave in lead II. There is an RS complex in lead I, 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 the standard lead I, the QRS complex is expressed as an R-type, and in lead III, its form is S-type. In this case, the S tooth has a depth greater than the height R.

With blockade of the posterior branch of the left leg of His, the alpha angle is 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 tall R wave (III, aVF).

When blocking the anterior branch of the left leg of His, the values will be from -300 and more. On the ECG signs of this are the late R wave (lead aVR). Leads V1 and V2 may have a small r wave. At the same time, the QRS complex is not expanded, and the amplitude of its teeth is not changed.

Blockade of the anterior and posterior branches of the left leg of His (complete blockade) - 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 expanded, and its top is serrated. Near the high R wave 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 serious illnesses cardiological nature.

The definition of these diseases begins with an ECG, and then methods such as echocardiography, radiography, coronary angiography are prescribed. And also can be carried out ECG with stress and daily monitoring by Holter.

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 we transfer these values to a conditional three-dimensional coordinate system, we can understand how the electrical axis of the heart is located and calculate its angle with respect 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 the impulse through the myocardium. The conduction system of the heart is atypical muscle fibers connecting different parts of the body. It begins with the sinus node, located between the mouths of the vena cava. Further, the impulse is transmitted to the atrioventricular node, localized in the lower part of the right atrium. The next baton is taken by the bundle of His, which quickly diverges into two legs - left and right. In the ventricle, the branches of the bundle of His immediately pass into the Purkinje fibers, penetrating the entire heart muscle.

EOS location options

Cardiac ischemia;

Chronic heart failure;

Cardiomyopathy of various origins;

congenital defects.

What is the danger of changing the EOS?

The normal value of EOS is the interval 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.

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

The change in the EOS, revealed on the cardiogram, cannot be set 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 occurring in it inevitably affect the work of the whole organism. Regular examinations of the therapist and the passage of an ECG will allow timely detection of the appearance of serious diseases 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 conical shape, with its narrow end pointing down, forward and to the left, and the electrical axis has a semi-vertical position, that is, it is also directed down and to the left, and when projected onto a coordinate system, it can be in the range from +0 to +90 0.

An ECG conclusion is considered normal, which indicates any of the following positions of the axis of the heart: not rejected, has a semi-vertical, semi-horizontal, vertical or horizontal position. Closer to the vertical position, the axis is in thin tall people asthenic physique, and to the horizontal - in strong, stocky faces of a hypersthenic physique.

The range of position of the electrical axis is normal

For example, in the conclusion of the ECG, the patient may see the following phrase: "sinus rhythm, EOS is not rejected ...", or "the axis of the heart is in a vertical position", which means that the heart is working correctly.

In the case of heart diseases, 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 deciphering the ECG by the attending physician, it is necessary to determine the direction of the electrical axis.

Deviations from the norm are the 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

Determining the position of the axis of the heart is carried out by a doctor of functional diagnostics, deciphering the ECG, using special tables and schemes, by 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 one, then there is a levogram, or a deviation of the axis to the left. If there is more in III than in I, then a rightogram. Normally, the R wave is higher in lead II.

Causes of deviations from the norm

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

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

Deviation of the axis of the heart 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 whole heart. Hypertrophy can be caused by such diseases:

cardiomyopathy (increase in mass of the myocardium or expansion of the heart chambers) due to anemia, disorders hormonal background in the body, coronary heart disease, postinfarction cardiosclerosis. changes in myocardial structure after myocarditis ( inflammatory process in cardiac tissue)
long standing arterial hypertension, especially with constantly high pressure figures;
acquired heart defects, in particular stenosis (narrowing) or insufficiency (incomplete closure) of the aortic valve, leading to impaired intracardiac blood flow, and, therefore, increased load to the left ventricle;
congenital heart defects are often the cause of the deviation of the electrical axis to the left in a child;
violation of conduction along the left leg of the bundle of His - complete or incomplete blockade, leading to impaired contractility of the left ventricle, while the axis is rejected, 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 axis of the heart to the right is a variant of the norm when conducting an ECG in a newborn child, and in this case there may be a sharp deviation of the axis.

In adults, such a deviation, as a rule, is a sign of right ventricular hypertrophy, which develops with such diseases:

diseases bronchopulmonary system- prolonged bronchial asthma, severe obstructive bronchitis, pulmonary emphysema, leading to an increase in blood pressure in the pulmonary capillaries and increasing the load on the right ventricle;
heart defects with damage to the tricuspid (tricuspid) valve and the valve of the pulmonary artery extending from the right ventricle.

The greater the degree of ventricular hypertrophy, the more deviated the electrical axis, 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. Disorders of well-being appear in a patient if myocardial hypertrophy leads to severe hemodynamic disturbances and to heart failure.

The disease is characterized by pain in the region of the heart

Of the signs of diseases accompanied by a deviation of the axis of the heart to the left or right, headaches, pain in the region of the heart, swelling are characteristic. lower extremities and on the 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 found on the cardiogram, an additional examination should be performed to establish the cause of this condition, especially if it is found in a child.

Diagnostics

To determine the reason for a deviation by ECG Axis heart to the left or right, a cardiologist or therapist may prescribe additional methods research:

Ultrasound of the heart is the most informative method that allows you to evaluate anatomical changes and identify ventricular hypertrophy, as well as determine the degree of violation of their contractile function. This method is especially important for examining a newborn child for congenital pathology hearts.
ECG with exercise (walking on a treadmill - treadmill test, bicycle ergometry) can detect myocardial ischemia, which can be the cause of deviations of the electrical axis.
24-hour ECG monitoring in the event that not only axis deviation is detected, but also the presence of a rhythm not from the sinus node, that is, there are rhythm disturbances.
Chest X-ray - with severe myocardial hypertrophy, an expansion of the cardiac shadow is characteristic.
Coronary angiography (CAG) is performed to clarify the nature of coronary artery lesions in coronary artery disease a.

Treatment

Directly, the deviation of the electrical axis does not need treatment, since this is not a disease, but a criterion by which it can be assumed that the patient has one or another cardiac pathology. If any disease is detected after the additional examination, it is necessary to begin its treatment as soon as possible.

In conclusion, it should be noted that if the patient sees in the conclusion of the ECG the 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 - a sign, even if there are no symptoms does not occur.

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With the vertical position of the EOS, 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 that is generated in the sinus node (the main source of cardiac electrical potentials).

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

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

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

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

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

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

Methods for determining the position of the EOS.

In simple terms, an ECG is a dynamic recording of an electrical charge, thanks to which our heart works (that is, it contracts). The designations of these graphs (they are also called leads) - I, II, III, aVR, aVL, aVF, V1-V6 - can be seen on the electrocardiogram.

An EKG is completely painless and safe study, it is carried out by 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. With an increase in heart rate above 91 beats / min, they speak of tachycardia; if the heart rate is 59 beats / min or less, this is a sign of bradycardia.

The electrical axis of the heart (EOS): the essence, the norm of the 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 the norm and does not require treatment.

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

Extrasystole 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 blockade, A-V (AV) blockade - a violation of the impulse from the atria to the ventricles of the heart.

Blockade of the legs (left, right, left and right) of the His bundle (RBNG, BLNG), complete, incomplete - this is a violation of the conduction of an impulse along the conduction system in the thickness of the ventricular myocardium.

by the most common causes hypertrophy 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 transferred. In such a situation, the doctor prescribes treatment aimed at preventing a second heart attack and eliminating the cause of circulatory disorders in the heart muscle (atherosclerosis).

Timely detection and treatment of this pathology is necessary. Normal ECG in children aged 1-12 months. Typically fluctuations in heart rate depending on the behavior of the child (increase in crying, anxiety). 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 the position of the EOS can talk about heart disease?

The direction of the electrical axis of the heart shows the total amount of bioelectrical 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 we project the electrodes onto a conditional coordinate system, then we can also calculate the angle of the electric axis, which will be located where the electrical processes are strongest. The conduction system of the heart is a section of the heart muscle, consisting of the so-called atypical muscle fibers.

Normal ECG

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 conduction system of the myocardium 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 the diagnosis of diseases. In itself, the position of the EOS is not a diagnosis.

These defects can be either congenital or acquired. The most commonly acquired heart defects are the result of rheumatic fever.

In this case, it is necessary to consult a highly qualified sports doctor to decide whether it is possible to continue playing sports.

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 with the left ventricle, RVH is caused by coronary heart disease, congestive heart failure, and cardiomyopathies.

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Department of Medical Cybernetics and Informatics, Russian National Research Medical University named after N.I. Pirogov

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

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

MOSCOW 2014

General about ECG

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

To register 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 (axes - in the horizontal plane).

Leads from limbs.

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, the electrodes are applied as follows: I - left hand and right arm, II - left leg and right arm, III - left leg and left arm.

In enhanced 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 due to the fact that the electrode that is applied to the limb under study is excluded from the zero electrode (for example, in the aVF lead, the combined electrode from the right hand and the left hand serves as the zero electrode).

On the right leg a ground electrode is always applied.

Breast leads.

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

The indifferent electrode is a conventional zero electrode.

The ECG in each lead is a projection of the total vector onto the axis of this lead. Thus, different leads, as it were, allow us to look at the electrical processes in the heart from different angles. The twelve ECG leads collectively create a three-dimensional picture of the electrical activity of the heart; in addition to them, additional leads are sometimes used. So, for the diagnosis of right ventricular infarction, the right chest leads V3R, V4R and others are used. Esophageal leads can 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 used.

Lead value

Why are there so many leads? 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 only see 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 EMF of the heart. The first 6 leads (3 standard and 3 reinforced from the extremities) 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 allows you to clarify the localization of the pathological focus (for example, myocardial infarction): the interventricular septum, the apex of the heart, the lateral sections 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 will 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, which can be used to assess the location of the pathological focus and the electrical axis of the heart.

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 that of the first 6 leads, in which the highest positive teeth are recorded, and is perpendicular to the lead in which the value of the positive teeth is equal to the value of the negative teeth. Two examples of determining the electrical axis of the heart are given at the end of the article.

Options for 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 (in thin people it is directed more vertically from the average values, and in obese people it is more horizontally). For example, with hypertrophy (growth) of the right ventricle, the axis of the heart deviates to the right. With conduction disorders, the electrical axis of the heart can deviate sharply to the left or right, which in itself is diagnostic sign. For example, with complete blockade of the anterior branch of the left branch of the bundle of His, there is a sharp deviation of the electrical axis of the heart to the left (α ≤ −30°), the posterior branch to the right (α ≥ +120°).

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

Complete blockade of the posterior branch of the left leg of the bundle of His. The EOS is sharply deviated to the right (α ≅+120°), since the highest 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 the ECG

Any ECG consists of teeth, segments and intervals.

The teeth are the bulges and concavities on the electrocardiogram. The following teeth are distinguished on the ECG:

P (atrial contraction),

Q, R, S (all 3 teeth characterize the contraction of the ventricles),

T (relaxation of the ventricles),

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 P-Q and S-T segments. For example, the P-Q segment is formed due to a delay in conduction of excitation in the atrioventricular (AV-) node.

An 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-teeth

Normally, the excitation wave propagates from the sinus node along the myocardium of the right and then the left atrium, and the total atrial depolarization vector is directed mainly 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 aVR.

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

QRS Complex

Normally, the wave of excitation 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, there is depolarization of the interventricular septum from left to right (vector 1), and then depolarization of the left and right ventricles (vector 2). Because the wave of depolarization spans the thick left ventricle for a longer time than the thin right ventricle, vector 2 faces left and backward. In the right chest leads, this two-phase process is reflected by a small positive tooth (septal r wave) and a deep S wave, and in the left chest leads (for example, in V6) it is reflected by a small negative tooth (septal q wave) and a large R wave. In leads V2-V5, the amplitude of the R wave gradually increases, the S-shape decreases. That lead in which the amplitude of the R and S waves is 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 prevailing, more precisely, the time-averaged direction of the total ventricular depolarization vector 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 a deviation of the axis to the left or right.

Deviation of the electrical axis of the heart to the left may be a variant of the norm, but more often caused by left ventricular hypertrophy, blockade of the anterior branch of the left leg of the His bundle, lower myocardial infarction.

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

False representation of the deviation of the electrical axis can occur when the electrodes are applied incorrectly.

T-teeth

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

U-Teeth

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

Tall U-prongs speak of increased risk pirouette tachycardia. Negative U-waves in the chest leads - always pathological sign; it can serve as the first manifestation of myocardial ischemia.

ECG analysis

General ECG decoding scheme

№ actions	Purpose of action	Action plan
	Checking the correctness of ECG registration.	Checking the fixation of the electrodes, checking the contacts, checking the operation of the device.
	Heart rate and conduction analysis	Evaluation of heart rate regularity
		Calculation of heart rate (HR)
		Determining the source of excitation
		Conductivity rating
	Determination of the electrical axis of the heart	Construction of the electrical axis of the heart, determination of its angles, evaluation of the obtained values
	Analysis of atrial P wave and P-Q interval	Analysis of the length, borders of teeth, interval and segments, evaluation of the obtained values
	Analysis of the ventricular QRST complex	Analysis of the QRS complex
		Analysis of the RS-T segment
		T wave analysis
		Analysis of the interval Q - T
	Electrocardiographic conclusion	Establishing diagnosis

ECG interpretation

Checking the correctness of the ECG registration

At the beginning of each ECG tape there must be a calibration signal - the so-called control 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 invalid. Normally, in at least one of the standard or augmented 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 variation in 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 correct.

counting the heart rate (HR)

Large squares are printed on the ECG film, each of which includes 25 small squares (5 vertical x 5 horizontal). For a quick heart rate calculation 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 approximately 4.8 large cells, which at a speed of 25 mm / s gives 300 / 4.8 = 62.5 bpm.

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

With an irregular rhythm, the maximum and minimum heart rates are usually considered according to the duration of the smallest and most large interval R-R respectively.

determination of the source of excitation

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 disturbances of excitability and conduction can be very intricately combined, which can lead to misdiagnosis and improper treatment. To correctly determine the source of excitation on the ECG, you need to know the conduction system of the heart well.

Determination of the electrical axis of the heart.

In the first part of the cycle about the ECG, it was explained what the electrical axis of the heart is and how it is determined in the frontal plane.

Analysis of the atrial P wave.

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 right atrial hypertrophy, for example, in cor pulmonale.

Split with 2 peaks, an extended P wave in leads I, aVL, V5, V6 is characteristic of left atrial hypertrophy, for example, with mitral valve defects.

P-Q interval: normal 0.12-0.20 s.

An increase in this interval occurs with impaired conduction of impulses through the atrioventricular node (atrioventricular block, AV block).

AV blockade is 3 degrees:

I degree - P-Q interval enlarged, but each P wave has its own QRS complex (no prolapsed 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 in their own rhythm, independently of each other. Those. an 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 blockade of the legs of the bundle of His.

Normally, the Q wave can be recorded in all standard and augmented 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. Lead aVR normally has a deep and wide Q wave and even a QS complex.

The R wave, like Q, 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 be of 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 assignment V3 (or between V2 - V4) "transitional zone" (equality of R and S teeth) is usually registered.

analysis of the RS-T segment

The ST segment (RS-T) is a segment from the end of the QRS complex to the beginning of the T wave. The ST segment is especially carefully analyzed in CAD, as it reflects a lack of oxygen (ischemia) in the myocardium.

Fine S-T segment located in the limb leads on the isoline (± 0.5 mm). In leads V1-V3, the S-T segment can be shifted 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.

analysis of the interval Q - T.

The Q-T interval is called the electrical systole of the ventricles, 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 a short-term increased excitability of the ventricular myocardium after their repolarization.

Electrocardiographic conclusion.

Should include:

Rhythm source (sinus or not).

Rhythm regularity (correct or not). Usually sinus rhythm is correct, although respiratory arrhythmia is possible.

The position of the electrical axis of the heart.

The presence of 4 syndromes:

rhythm disorder
conduction disorder
hypertrophy and/or congestion 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 one.

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

If we indicate 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 axle arrangement.

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

The doctor may conclude:

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

All of these conclusions are the norm.

As for individual characteristics, it is noted that in people of high stature and thin build, the EOS is in a semi-vertical position, and in people who are lower and at the same time they are of a stocky build, the EOS has 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 state, the cavity is stretched, increases in size. Sometimes this is due to overload, but it can also be the result of a disease.

Diseases that cause hypertrophy are:

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

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

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

This pathology can be caused by such diseases:

As well as diseases characteristic of LV hypertrophy:

ischemia of the heart;
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 the norm.

It can be concluded 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. An axis change is simply an ECG sign of some kind of disease.

It is important to timely determine these indications and diseases.

With the manifestation of symptoms of a cardiological nature, you should immediately undergo an electrocardiography.

Definition of ECG signs

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

When blocking the anterior branch of the left leg of His, the values will be from -300 and more. On the ECG, signs of this are a late R wave (lead aVR). Leads V1 and V2 may have a small r wave. At the same time, the QRS complex is not expanded, and the amplitude of its teeth is not changed.

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 diseases of a cardiological nature.

The definition of these diseases begins with an ECG, and then methods such as echocardiography, radiography, coronary angiography are prescribed. And also an ECG with a load and daily monitoring according to the Holter can be performed.

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How is an electrocardiogram taken?

The ECG is recorded in a special room, shielded as much as possible from various electrical interferences. The patient is comfortably positioned 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 with 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 if there are abnormalities in the functioning of the organ, and, if necessary, refer the patient for a consultation with a cardiologist.

What affects 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 the impulse 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. Further, the impulse is transmitted to the atrioventricular node, localized in the lower part of the right atrium. The next baton is taken by the bundle of His, which quickly diverges into two legs - left and right. In the ventricle, the branches of the bundle of His immediately pass into the Purkinje fibers, penetrating the entire heart muscle.

The impulse that came to the heart cannot escape the conduction system of the myocardium. This is a complex structure with fine settings, sensitive to the slightest changes in the body. With any disturbances in the conduction system, the electrical axis of the heart is able to change its position, which will immediately be 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 larger than that of the right one. In this case, 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 precisely 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 of +30 to +70 degrees. Most often, these values are recorded on the ECG. The electrical axis of the heart can also be located in the range from 0 to +90 degrees, and this, according to cardiologists, is also the norm. Why are there such differences?

Normal location of the electrical axis of the heart

There are three main provisions of the EOS. The normal range is from +30 to +70°. This variant 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, densely built patients. In their card, the doctor will mark the EOS angle from 0 to + 30 °. Each of these options is the norm 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 in itself a diagnosis. However, such changes on the electrocardiogram may indicate various disorders in the work of the most important organ. The following diseases lead to serious changes in the functioning of the conduction system:

Cardiac ischemia;

Chronic heart failure;

Cardiomyopathy 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 inpatient treatment. In some cases, when registering a deviation of the EOS, the patient needs emergency assistance in intensive care.

Deviation of the electrical axis of the heart to the left

Most often, such changes on the ECG are noted with an increase in the left ventricle. This usually happens with the progression of heart failure, when the organ simply cannot fully perform its function. It is not excluded the development of such a condition in arterial hypertension, 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 the inevitable violation of the passage of the impulse through the myocardium.

Deviation of the electrical axis of the heart to the left also occurs with narrowing of the aortic orifice. In this case, there is a stenosis of the lumen of the valve located at the outlet of the left ventricle. This condition is accompanied by a violation of the normal blood flow. Part of it lingers in the cavity of the left ventricle, causing it to stretch, and, as a result, compaction of its walls. All this causes a regular change in the 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 some respiratory diseases (for example, in bronchial asthma or chronic obstructive pulmonary disease). Some congenital heart defects can also cause an enlarged right ventricle. First of all, here it is worth noting stenosis of the pulmonary artery. In some situations, tricuspid valve insufficiency can also lead to the occurrence of a similar pathology.

What is the danger of changing the EOS?

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 in connection with the blockade of the bundle of His. In this case, the conduction of the impulse along the myocardium is disrupted, which means that 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 rejected both to the left and to the right, depending on the localization of the process. The cause of the blockade can be myocardial infarction, an infectious lesion of the heart muscle, as well as taking certain drugs. A conventional 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 provide normal work organ.

What to do if the EOS is changed?

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

Summing up, several important points should be highlighted:

The normal value of EOS is the interval 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.

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

The change in the EOS, revealed on the cardiogram, cannot be set as a diagnosis, but is a reason to visit a cardiologist.

is a term that means the electrical activity of an organ, that is, the total indicator of its average vector during depolarization. This is an indicator of the electrical processes of the heart.

This concept is used in cardiology and in functional diagnostics. Determining the direction of the EOS is carried out using an ECG.

In the direction of the axis, the doctor determines bioelectrical changes that occur in the myocardium during contraction.

To determine the direction of the EOS, there is a coordinate system that is located on the entire chest.

With electrocardiography, the doctor can set the electrodes according to the coordinate system, while it will be clear where the axis angle is, that is, the places where the electrical impulses are strongest.

The impulses pass through. It consists of atypical fibers that are located in certain areas of the body.

This system begins in the sinus node. Further, the impulse passes to the atria and ventricles and to the bundle of His.

When any violations occur in the conductor system, then the EOS changes its direction.

Axis location

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

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

If we indicate 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 axle arrangement.

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

The doctor may conclude:

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

All of these conclusions are the norm.

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 state, the cavity is stretched, increases in size. Sometimes this is due to overload, but it can also be the result of a disease.

Diseases that cause hypertrophy are:

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

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

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

This pathology can be caused by such diseases:

As well as diseases characteristic of LV hypertrophy:

ischemia of the heart;
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 the norm.

It can be concluded 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. An axis change is simply an ECG sign of some kind of disease.

It is important to timely determine these indications and diseases.

With the manifestation of symptoms of a cardiological nature, you should immediately undergo an electrocardiography.

Definition of ECG signs

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

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

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 diseases of a cardiological nature.

The electrical axis of the heart (EOS) is a concept that implies the activity of conducting nerve excitations synthesized and performed in the heart.

This indicator is characterized by the amount of conduction of electrical signals through the cavities of the heart, occurring with any contraction of the heart tissues.

The electrical axis of the heart is one of the characteristics determined by the ECG. To make a diagnosis, it is necessary to conduct additional hardware studies.

During an electrocardiogram study, the device captures nerve excitations emitted by different parts of the heart by applying electrocardiograph sensors to different parts of the chest.

To calculate the direction of the EOS, doctors use a coordinate system, comparing the location of the heart with it. Due to the projection of electrodes onto it, the angle of the EOS is calculated.

In places where the zone of the heart muscle, in which the electrode is installed, emits stronger nerve excitations, there is the EOS angle.

Why is the normal conduction of electrical excitations of the heart so important?

The fibers that make up the heart perfectly conduct nerve excitations, and with their multitude create the cardiac system, where they conduct these nervous excitations.

The initial functioning of the heart muscle begins in the sinus node, with the appearance of nervous excitation. Next, the nerve signal is transported to the ventricular node, which transmits the signal to the bundle of His, through which the signal propagates further.

The location of the latter is localized in the septum separating the two ventricles, where it branches into the anterior and posterior legs.

The nervous excitation conduction system is very important for the healthy functioning of the heart, because, thanks to electrical impulses, it sets the normal rhythm of heart contractions, which sets the healthy functioning of the body.

If deviations appear in the signal conduction structure, then significant deviations in the position of the EOS are possible.

How is the electrical axis of the heart determined?

Reveal the location of the EOS, subject to the attending physician, deciphering the ECG using diagrams and tables, and finding the alpha angle.

This angle is formed from two straight lines. One of them is the 1st axis of abduction, and the second is the line of the vector of the electrical axis of the heart.

Location features include:

Normal	If the location of the angle is within plus thirty - plus sixty nine, then this indicates normal indicators of the electrical axis of the heart
Vertical EOS	Registered when defining the axis within seventy - ninety degrees
Horizontal	When the angle is in the range from zero to thirty degrees
Offset to the left	The position of the ventricle is within an angle from zero to minus ninety degrees
Offset right	It is registered with indicators of the position of the ventricle in the range from ninety-one to one hundred and eighty.

Another way to identify the electrical axis of the heart is to compare QRS complexes, the main task of which is the synthesis of nerve excitations and contraction of the ventricles.

Definition indicators are given below:

Normal	With these electrical axis values, the R-wave of the second lead is larger than the R-wave in the first lead, and the similar tooth of the third compartment is smaller than in the first. (R2>R1>R3)
Left Deviation	If the normal position of the electrical axis is violated to the left side, the R-tooth of the first compartment is recorded - the largest, and the second and third, respectively, are smaller. (R1>R2>R3)
Right Deviation	Violation of the electrical axis of the heart in right side characterized by the largest third R-wave, and a corresponding decrease in the second and first. (R1

To accurately determine the height of the teeth, if they are approximately at the same level, use the following technique:

QRS complexes are determined in leads 1 and 3;
The height of the R-teeth of the 1st lead is summarized;
A similar operation is performed with the R-teeth of the 3rd lead;
The resulting sums are inserted into a certain table, the data joining point corresponding to a certain corner radius is identified. By identifying the normal values of the alpha angle, you can easily determine the location of the EOS.

You can also determine the position of the electric axis with a pencil. This method is not accurate enough, and is used, in many cases, by students.

To determine in this way, attach the back of the pencil to the results of the electrocardiogram in the places of three leads and determine the highest R-wave.

After that, the sharp side of the pencil is directed to the R-wave, to the lead, where it is as large as possible.

Normal indicators of EOS

The boundaries of normal levels of the electrical axis of the heart are determined by the study of the electrocardiogram.

In weight ratio, the right ventricle is larger than the left. Therefore, in the latter, nervous excitations are much stronger, which directs the EOS to it.

If we compare the heart with the coordinate system, then its position will be in the range from thirty to seventy degrees.

This arrangement is normal for the axis. But its position can fluctuate from zero to ninety degrees, which varies from the personal parameters of the human body:

Horizontal. In the majority of cases, it is recorded in people of short stature, but with a wide sternum;
Vertical. Mostly recorded in people of high stature, but thin build.

When fixing the electrical axis of the heart, the above positions are rarely noted. Semi-horizontal and semi-vertical positions of the axis are recorded in the predominant number of cases.

All of the above location options are normal indicators. Turns of the heart on the projection on the coordinate system will help determine the location of the heart, and diagnose possible diseases.

In the results of the electrocardiogram, rotations of the EOS around the coordinate axis can be recorded, which may be the norm. Such cases are considered individually, depending on the symptoms, condition, complaints of the patient and the results of other examinations.

Violations of the norm indicators are deviations to the left or right.

Normal indicators in children

For infants, he notes a clear axis shift on the ECG, in the process of growth it normalizes. For a period of one year from birth, the indicator is usually located vertically. Normalization of the position is characterized by an increase and development of the left ventricle.

In children of school and preschool age, the normal electrical axis of the heart predominates, and there is also a vertical and very rarely horizontal.

Norms for children:

Infants, ninety to one hundred and seventy degrees;
Children from one to three years old - the vertical position of the axis;
Adolescent children - the normal position of the axis.

What is the purpose of EOS?

Only one displacement of the electrical axis of the heart does not diagnose the disease. This factor is one of the parameters on the basis of which abnormalities in the body can be diagnosed.

In certain pathologies, axis deviation is most characteristic.

These include:

insufficient supply of blood to the heart;
Primary damage to the heart muscle, not associated with inflammatory, tumor, ischemic lesions;
Heart failure;
Heart defects.

What does EOS shift to the right mean?

Complete blockade of the posterior branch of the bundle of His also leads to a violation of the electrical axis to the right. In the case of registering a right-sided displacement, a pathological increase in the dimension of the right ventricle, which is responsible for supplying blood to the lungs, is possible for oxygen saturation.

This disease is caused by narrowing of the arteries of the lung and insufficiency of the tricuspid valve.

Pathological growth of the right ventricle occurs with ischemia and / or heart failure, and other diseases that do not occur under the influence of inflammatory and ischemic processes.

What does the displacement of the EOS to the left mean?

When determining the displacement of the electrical axis to the left side, it may indicate a pathological increase in the left ventricle, as well as its overload.

This pathological condition, in most cases, is provoked by the following factors of influence:

Persistent increase in blood pressure, which leads to the fact that the ventricle contracts much more strongly. Such a process leads to the fact that it grows in weight, and, accordingly, in size;
Ischemic attacks;
Heart failure;
Primary heart lesions not associated with ischemic and inflammatory processes;
Left ventricular valve disease. It involves the narrowing of the largest vessel in the human body - the aorta, in which the normal ejection of blood from the left ventricle is disrupted, and its valve insufficiency, when some part of the blood is thrown back into the left ventricle;
People involved in sports at a professional level. In this case, it is necessary to consult a sports doctor about further sports activities.

Violation of the normal boundaries of the electrical axis can be both a congenital indicator and an acquired one. In most situations, heart defects are the consequences of a fever caused by rheumatism.

Also, displacements of the electrical axis to the left side can appear with a displacement of the conduction of nerve excitations inside the ventricles, and blockade of the anterior leg of the His bundle.

Symptoms

A separate displacement of the EOS does not entail any symptoms. But since it occurs as a consequence of some pathological condition, the symptoms correspond to the disease present in the body.

The most common symptoms are:

If you find the slightest symptoms, you should seek the advice of a cardiologist. Timely diagnosis and effective treatment can save a patient's life.

Diagnostics

To diagnose diseases associated with a violation of the electrical axis of the heart, it is required to conduct several hardware studies, in addition to the ECG, to confirm the diagnosis.

These include:

Ultrasound examination (ultrasound). It is a method that provides a large amount of information about the state of the heart, in which it is possible to determine structural disorders in the heart. During this examination, a visual picture of the state of the heart is displayed on the screen, which will help diagnose enlargement. The method is safe and painless, which makes it available to any category of people, including infants and pregnant women;
Daily electrocardiogram. Allows you to determine the slightest disturbances in the work of the heart, by the method of research by an electrocardiograph throughout the day;
MRI of the heart- is a very complex type of safe research and is very effective. Many mistakenly think that it is associated with ionizing radiation, but it is not. The basis of MRI is a magnetic field, as well as radio frequency pulses. During the examination, the patient is placed in a special apparatus - a tomograph;
Load tests (treadmill, bicycle ergometry). A treadmill is a study during exercise on a special type of treadmill. Bicycle ergometer - a similar way to check, but with the help of a special bike;
X-ray of the sternum. During this method of research, the patient is irradiated with x-rays. The results help determine the enlargement of the heart;
Coronography.
The choice of research method belongs to the attending physician, depending on the patient's complaints and symptoms.

Treatment
All the diseases listed in this article can be diagnosed by only one violation of the electrical axis. If a shift is detected, it is necessary to consult a cardiologist and conduct additional studies.
Registration of a violation in one direction or another does not require treatment.

It normalizes after the initial pathological condition is eliminated. And only by eliminating it, the indicators of the electric axis return to normal.

What could be the consequences?
The onset of burdens depends on the disease that provoked the deviation of the electrical axis.
Due to insufficient blood supply to the heart (ischemia), the following complications can progress:
- Tachycardia. A pathological increase in the rate of contractions of the heart occurs when the myocardium does not have enough blood volume for healthy work, which it tries to compensate for in a large number of contractions;
- Death of heart tissue. The progression of a heart attack due to prolonged oxygen starvation, provoked by insufficient blood supply to the heart, is inevitable;
- Circulation failure in the body. Against the background of circulatory failures in the body, blood stagnation, tissue death of vital organs, gangrene and other irreversible complications can progress;
- Violation of the structure of the heart;
- Fatal outcome. Extensive myocardial infarction and other serious burdens can lead to rapid death.
To prevent the development of serious complications and to prevent possible unexpected death, if symptoms are detected, you should immediately go to the hospital.

Examinations will help doctors to correctly diagnose the disease, and prescribe effective therapy or surgery.

What is the electrical axis of the heart and what are the consequences of deviations from the norm? Deviation of the electrical axis.

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

The conduction system of the heart and why is it important to determine the EOS?

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

When the position of the EOS can talk about heart disease?

EOS deviations to the left

EOS deviations to the right

What to do if an EOS shift is found on the cardiogram?

Video: EOS in the course “ECG for everyone”

Influence of the anatomical position of the heart on the electrical axis of the QRS complex

Influence of the direction of ventricular depolarization

How to recognize EOS deviation to the right and left

Right axis deviation

The conduction system of the heart and why is it important to determine the EOS?

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

When the position of the EOS can talk about heart disease?

EOS deviations to the left

EOS deviations to the right

What to do if an EOS shift is found on the cardiogram?

Normal values ​​and causes of violation

Diagnostics on the ECG

Alpha Offset Detection

Visual Definition

Establishing diagnosis

Diseases that are accompanied by a levogram

Additional Research

Treatment

Axis location

Reasons for rejection

Definition of ECG signs

EOS location options

What is the danger of changing the EOS?

The range of position of the electrical axis is normal

How to determine the position of the electrical axis

Causes of deviations from the norm

Symptoms

Diagnostics

Treatment

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

Methods for determining the position of the EOS.

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

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

When the position of the EOS can talk about heart disease?

Normal ECG

Axis location

Reasons for rejection

Definition of ECG signs

How is an electrocardiogram taken?

What affects the location of the EOS?

EOS location options

Normal location of the electrical axis of the heart

Pathological location of the electrical axis of the heart

Deviation of the electrical axis of the heart to the left

Deviation of the electrical axis of the heart to the right

What is the danger of changing the EOS?

What to do if the EOS is changed?

Axis location

Reasons for rejection

Definition of ECG signs

Why is the normal conduction of electrical excitations of the heart so important?

How is the electrical axis of the heart determined?

Normal indicators of EOS

Normal indicators in children

What is the purpose of EOS?

What does EOS shift to the right mean?

What does the displacement of the EOS to the left mean?

Symptoms

Diagnostics

Treatment

What could be the consequences?

Normal values and causes of violation