What is the horizontal position of the electrical axis of the heart. The concept of “uncertain electrical position of the heart”

The electrical axis of the heart (EOS) is the first word that every person sees when they have a transcript of the cardiogram in their hands. When a specialist next to them adds that the EOS is in a normal position, the person being examined has nothing to worry about his health. But what if the axis takes a different position or has deviations?

It is no secret that the heart is constantly working and producing electrical impulses. The place of their formation is the sinus node, from which they normally pass this way:

1. Atria.
2. Ventricles.
3. Bundle of His.

As a result, the movement is an electric vector with strictly designated movement. The electrical axis of the heart represents the projection of the impulse onto the anterior plane, which is in a vertical position.

The placement of the axis is calculated by dividing the circle drawn around the triangle by degrees. The direction of the vector gives the specialist an approximate idea of ​​the location of the heart in the chest.

EOS

The concept of EOS norm

The position of the EOS depends on:

• The speed and correctness of impulse movement through the cardiac systems.
• Quality of myocardial contractions.
• Conditions and pathologies of organs that affect the functionality of the heart.
• Heart condition.

For a person who does not suffer from serious illnesses, characteristic axis:

• Vertical.
• Horizontal.
• Intermediate
• Normal.

The normal position of the EOS is located according to Died at coordinates 0 - +90º. For most people, the vector passes the limit of +30 - +70º and is directed to the left and down.

In an intermediate position, the vector passes within +15 - +60 degrees.

According to the ECG, the specialist sees that the positive waves are longer in the second, aVF and aVL leads.

Correct placement of EOS in children

Babies have a strong axis deviation in right side, which during the first year of life turns into vertical plane. This situation has a physiological explanation: right part the heart “overtakes” the left in weight and production of electrical impulses. The transition of the axis to normal is associated with the development of the LV.

Children's EOS standards:

• Up to a year - the passage of the axis is between +90 - +170 degrees.
• From one to three years - vertical EOS.
• 6-16 – stabilization of indicators to adult standards.

Measuring indicators using electrocardiography

ECG signs in the analysis of EOS are determined by the rightogram and the leftogram.

A rightogram is finding a vector between indicators 70-900. On electrocardiography it is demonstrated by long R waves in the QRS group. The vector of the third lead is larger than the wave of the second. For the first lead, the RS group is considered normal, where the depth of S exceeds the height of R.

Pravogram

The levogram on an ECG is the alpha angle passing between 0-500. Electrocardiography helps to determine that the usual lead of the first QRS group is characterized by an R-type expression, but already in the third lead it has an S-type shape.

Levogram

Why does deviation occur?

When the axis is deviated to the left, this means that the patient has left ventricular hypertrophy.

The causes of the disease include:

1. Hypertension. Especially in cases of frequent increases in blood pressure.
2. Ischemic diseases.
3. Chronic heart failure.
4. Cardiomyopathy. This disease is the growth of the heart muscle in a mass and expansion of its cavities.
5. Pathology aortic valve. They can be congenital or acquired. They provoke blood flow disturbances and LV reloading.

Important! Very often, hypertrophy worsens in people who spend a lot of time on varied sports activities.

With a strong deviation of the axis to the right, a person may have hypertrophy of the PR, which is caused by:

1. High pressure in the arteries of the lungs, which causes bronchitis, asthma and emphysema.
2. Pathological diseases of the tricuspid valve.
3. Ischemia.
4. Heart failure.
5. Blocking of the posterior branch of the His node.

ECG for “cor pulmonale”

Vertical position of the EOS

A vertical position is characterized by a range of +70 - +90º. Characteristic of tall, thin people with a narrow sternum. According to anatomical indicators, with such a physique, the heart seems to be “hanging.”

On the electrocardiogram, the highest positive vectors are observed in aVF, negative ones - in aVL.

Horizontal position of the EOS

In a horizontal position, the vector passes between +15 - -30º. Most often observed in people with a hypersthenic physique: short stature, wide chest, excess weight. From an anatomical point of view, in this case, the heart is located on the diaphragm.

On the cardiogram, the highest positive waves appear in aVL, and negative ones in aVF.

Horizontal position of the EOS

EOS deviation to the left

Deviation of the electrical axis in left side the location of the vector in the range 0 - -90º is called. Distance up to -30º in some cases goes as the norm, but the slightest excess of the indicator can be regarded as a symptom of a serious illness. In some people, such indicators are provoked by deep exhalation.

Important! In women, a change in the coordinates of the heart in the chest can be triggered by pregnancy.

Reasons why the axis deviates to the left:

• LV hypertrophy.
• Disruption or blockage of the His bundle.
• Myocardial infarction.
• Myocardial dystrophy.
• Heart defects.
• Violation of CM contractions.
• Myocarditis.
• Cardiosclerosis.
• Calcium accumulations in the organ, blocking normal contraction.

These ailments and pathologies can provoke an increase in the mass and size of the LV. Because of this, the tooth on this side is longer, resulting in a deviation of the electrical axis to the left.

Reasons for EOS deviation to the right

The deviation of the axis to the right is fixed when it passes between +90 - +180º. This shift can be caused by:

1. Damage to the pancreas by infarction.
2. The simultaneous occurrence of coronary artery disease and hypertension - they deplete the heart with a vengeance and provoke failure.
3. Pulmonary diseases of a chronic nature.
4. Incorrect passage of electrical impulses along the right branch of the His bundle.
5. Pulmonary emphysema.
6. Severe strain on the pancreas caused by obstruction pulmonary artery.
7. Dextrocardia.
8. Mitral heart defect, which provokes pulmonary hypertension and stimulates the work of the pancreas.
9. A thrombotic block of blood flow in the lungs, which causes a deficiency of the organ in the blood and overloads the entire right side of the heart.

Because of these pathologies, the specialist determines on electrocardiography that the EOS is deviated to the right.

EOS deviation to the right

What to do if the axis is deviated?

If you are diagnosed with a pathological deviation of the axis, the specialist must resort to new studies. Each ailment that provokes displacement of the EOS is accompanied by several symptoms that require careful analysis. Most often they resort to ultrasound diagnostics hearts.

Finally

Determining the electrical axis of the heart is just a technique that allows you to understand the location of the heart and diagnose it for the presence of pathologies and ailments. A conclusion on it can only be drawn qualified specialist, since deviation does not always mean the presence of heart problems.

More:

Classification sinus rhythm: What can a cardiogram tell you about the condition of the heart?

The electrical axis of the heart is connected with the total vector of the electrodynamic force of the heart. Most often, it coincides with the anatomical axis of the organ. As a rule, the heart has the shape of a cone, with its narrow part directed down to the left and forward. In this case, the position of the electrical axis is in the range from 0 to 90 degrees.

The presence of the electrical axis is determined by the muscle fibers. Thanks to their contractions, the heart contracts.

The contraction originates in the sinus node, where an electrical impulse occurs. This impulse travels through the atrioventricular node and is directed to the His bundle. If there are disturbances in the conduction system, the electrical axis of the heart can change its position.

How can the EOS be located?

The location of the electrical axis of the heart can be determined using an ECG. The following options are usually considered normal:

• Vertical (location range from 70 to 90 degrees).
• Horizontal (location range from 0 to 30 degrees).
• Semi-horizontal.
• Semi-vertical.
• No tilt.

The figure shows the main options for the passage of the electrical axis of the heart. It is possible to determine what type of axis location is characteristic of a particular person (vertical, horizontal or intermediate) using an ECG.

Electrical axis of the heart

Often the position of the EOS depends on the person’s physique.

For tall people with a thin physique, a vertical or semi-vertical type of arrangement is characteristic. Short and dense people are characterized by horizontal and floor horizontal position EOS.

Intermediate options for placement of EOS are formed due to the fact that the physique of each person is individual, and there are many others between thin and dense body types. This explains the different positions of the EOS.

Deviations

Deviation of the electrical axis of the heart to the left or right is not a disease in itself. Most often, this phenomenon is a symptom of another pathology. Therefore, doctors pay attention to this anomaly and conduct diagnostics to determine the reasons why the axis has changed its position.

Axial deviation to the left is sometimes observed in healthy people who are actively involved in sports.

But most often this phenomenon indicates left ventricular hypertrophy. This disease is characterized by an increase in the size of this part of the heart. It may be accompanied by the following diseases:

If the electrical axis of the heart is shifted to the right, this can also be considered normal, but only in the case of a newborn child. The baby may even have a strong deviation from the norm.

Note! In other cases, this position of the electrical axis is a symptom of right ventricular hypertrophy.

Diseases that cause it:

• Problems with respiratory system(asthma, obstructive bronchitis).
• Heart defects.

The more pronounced the hypertrophy, the more the EOS changes position.

Tetralogy of Fallot (disorder)

Also, the electrical axis of the heart may be displaced due to coronary artery disease or heart failure.

Do I need treatment?

If the EOS has changed its position, unpleasant symptoms, as a rule, does not arise. More precisely, they do not arise due to axis deviation. All difficulties are usually associated with the cause that caused the displacement.

Most often, this cause is hypertrophy, so the symptoms occur the same as with this disease.

Sometimes no signs of the disease may appear until more serious illnesses heart and cardiovascular system.

Cardiac hypertrophy

To avoid danger, any person needs to carefully monitor their well-being and pay attention to any discomfort, especially if they are repeated frequently. You should consult a doctor if you have the following symptoms:

All these signs may indicate the development of heart disease. Therefore, the patient needs to visit a cardiologist and undergo an ECG. If the electrical axis of the heart is displaced, then additional diagnostic procedures need to be performed to find out what is causing this.

Diagnostics

To establish the cause of the deviation, use following methods diagnostics:

• Ultrasound of the heart
• Holter monitoring
• Coronary angiography

Ultrasound of the heart

This diagnostic method allows you to identify changes in the anatomy of the heart. It is with its help that hypertrophy is detected, and the peculiarities of the functioning of the heart chambers are determined.

The diagnostic method applied not only to adults, but also to very young children to ensure that they do not have serious pathologies.

Holter monitoring

In this case, an ECG is performed within 24 hours. The patient performs all his usual activities during the day, and the devices record the data. This method is used in case of deviations in the position of the EOS, accompanied by a rhythm outside the sinus node.

This method also makes it possible to judge the presence of hypertrophy, since the cardiac shadow will be expanded in the image.

ECG during physical activity

The method is a conventional ECG, the data of which is recorded while the patient is performing physical exercise(running, push-ups).

In this way, it is possible to establish coronary heart disease, which can also affect changes in the position of the electrical axis of the heart.

Coronary angiography

I use this method to diagnose problems with blood vessels.

Deviation of EOS does not imply therapeutic effects. The disease that caused the defect should be treated. Therefore, after a thorough examination, the doctor must prescribe the necessary therapeutic interventions.

This defect, identified during the examination, requires examination, even if the patient does not have any complaints about the heart. Heart diseases often occur and develop asymptomatically, which is why they are detected too late. If the doctor, after diagnosing, prescribed treatment and advised to adhere to certain rules, this needs to be done.

Treatment of this defect depends on what disease caused it, so the methods may be different. The main one is drug therapy.

In extremely life-threatening situations, the doctor may recommend surgery aimed at neutralizing the underlying disease.

At timely detection pathology of EOS can be returned to normal condition, what happens after the underlying disease is eliminated. However, in most cases, doctors’ actions are aimed at preventing deterioration in the patient’s condition.

May also be useful as treatment traditional methods using medicinal fees and tinctures. But before using them, you need to ask your doctor whether such actions will harm you. It is unacceptable to start taking medications on your own.

It is also important to follow measures to prevent heart disease. They are associated with a healthy lifestyle, nutritious food and rest, reducing the amount of stress. It is necessary to carry out feasible loads and maintain active image life. From bad habits and coffee abuse should be avoided.

Changes in the position of the EOS do not necessarily indicate problems in the human body. But detection of such a defect requires attention from doctors and the patient himself.

If measures are prescribed therapeutic effects, then they are related to the cause of the defect, and not to the defect itself.

By itself incorrect location electrical axis means nothing.

In contact with

The heart, like any human organ, is controlled by packets of impulses coming from the brain through nervous system. It is obvious that any violation of the control system leads to serious consequences for the body.

The electrical axis of the heart (EOS) is the total vector of all impulses observed in the conduction system of this organ during one contraction cycle. Most often it coincides with the anatomical axis.

The norm for the electrical axis is the position in which the vector is located diagonally, that is, directed down and to the left. However, in some cases this parameter may deviate from the norm. Based on the position of the axis, a cardiologist can learn a lot about the work of the heart muscle and possible problems.

Depending on a person’s physique, there are three main values ​​of this indicator, each of which is considered normal under certain conditions.

• In most patients with a normal build, the angle between the horizontal coordinate and the vector of electrodynamic activity ranges from 30° to 70°.
• For asthenics and skinny people the normal angle reaches 90°.
• In short, dense people, on the contrary, the angle of inclination is smaller - from 0° to 30°.

Thus, the position of the EOS is influenced by the constitution of the body, and for each patient the norm for this indicator is relatively individual.

The possible position of the EOS is shown in this photo:

Reasons for changes

The deviation of the vector of electrical activity of the heart muscle itself is not a diagnosis, but may indicate, among other things, serious disorders. Its position is influenced by many parameters:

• organ anatomy leading to hypertrophy or;
• malfunctions in the conductive system of the organ, in particular, which is responsible for conducting nerve impulses to the ventricles;
• cardiomyopathies due to various causes;
• chronic heart failure;
• persistent hypertension for a long time;
• chronic respiratory diseases such as obstructive pulmonary disease or bronchial asthma, can lead to deviation of the electrical axis to the right.

In addition to the above reasons, temporary deviations in EOS can cause phenomena not directly related to the heart: pregnancy, ascites (fluid accumulation in the abdominal cavity), intra-abdominal tumors.

How to determine on an electrocardiogram

The EOS angle is considered one of the main parameters that is studied at. For a cardiologist, this parameter is an important diagnostic indicator, the abnormal value of which clearly signals various violations and pathologies.

By studying the patient's ECG, the diagnostician can determine the position of the EOS by examining QRS complex waves, which show the work of the ventricles on the graph.

An increased amplitude of the R wave in the I or III chest leads of the graph indicates that the electrical axis of the heart is deviated to the left or right, respectively.

In the normal position of the EOS, the greatest amplitude of the R wave will be observed in the II chest lead.

Diagnosis and additional procedures

As mentioned earlier, deviation of the EOS to the right on the ECG is not considered a pathology in itself, but serves diagnostic sign disorders of its functioning. In the vast majority of cases this symptom indicates that the right ventricle and/or right atrium is abnormally enlarged, and finding out the causes of such hypertrophy allows you to make a correct diagnosis.

For a more accurate diagnosis, the following procedures can be used:

• ultrasound examination is a method with the highest information content showing changes in the anatomy of an organ;
• Chest x-ray may reveal myocardial hypertrophy;
• used if, in addition to EOS deviation, there are also rhythm disturbances;
• ECG under stress helps in detecting myocardial ischemia;
• Coronary angiography (CAG) diagnoses lesions coronary arteries, which can also lead to EOS tilt.

What diseases are caused

A pronounced deviation of the electrical axis to the right may indicate the following diseases or pathologies:

• Cardiac ischemia. , characterized by blockage of the coronary arteries that supply blood to the heart muscle. When uncontrolled, it leads to myocardial infarction.
• Congenital or acquired. This is the name given to the narrowing of this large vessel, which prevents the normal flow of blood from the right ventricle. Leads to increased systolic blood pressure and, as a consequence, to myocardial hypertrophy.
• Atrial fibrillation. Erratic electrical activity in the atria, which can eventually cause a cerebral stroke.
• Chronic cor pulmonale . Occurs when there is a malfunction of the lungs or pathologies of the chest, which lead to the inability of the left ventricle to function fully. Under such conditions, the load on the right ventricle increases significantly, which leads to its hypertrophy.
• Defect interatrial septum . expressed in the presence of holes in the septum between the atria, through which blood can be discharged from the left side to the right. As a result, heart failure and pulmonary hypertension develop.
• Stenosis mitral valve - between the left atrium and the left ventricle, which leads to difficulty in diastolic blood flow. Refers to acquired defects.
• Pulmonary embolism. Caused by blood clots, which, after occurring in large vessels move around circulatory system And .
• Primary pulmonary hypertension- blood in the pulmonary artery, which is caused by various reasons.

In addition to the above, a tilt of the EOS to the right may be a consequence of poisoning with tricyclic antidepressants. The somatotropic effect of such drugs is achieved by the influence of the substances they contain on the conductive system of the heart, and thus they can harm it.

What to do

If the electrocardiogram showed a tilt of the electrical axis of the heart to the right, it should be without delay, carry out a more extensive diagnostic examination at the doctor's. Depending on the problem identified during a more in-depth diagnosis, the doctor will prescribe appropriate treatment.

The heart is one of the most important parts human body, and therefore his condition should be the subject increased attention. Unfortunately, they often remember about it only when it starts to hurt.

To prevent such situations, you need to at least stick to general recommendations for the prevention of heart disorders: eat right, do not neglect a healthy lifestyle, and be examined by a cardiologist at least once a year.

If in the results of the electrocardiogram there is a record of a deviation of the electrical axis of the heart, a more in-depth diagnosis should be immediately carried out to determine the causes of this phenomenon.

Introduction

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

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

1. What is the resulting vector?

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

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

2. What is the electrical axis of the heart?

Electric axis hearts called the projection of the resulting vector of ventricular excitation in the frontal plane.

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

3. What is the alpha angle?

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

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

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

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

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

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

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

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

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

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

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

4. What is the electrical position of the heart?

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

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

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

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

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

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

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

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

A little reminder:

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

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

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

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

Conclusion.

Everything you need to study ECG interpretation, definitions of the electrical axis of the heart can be found in the section of the site: "". The section contains both clear articles and video tutorials.
If there are problems with understanding or decoding, we are waiting for questions on the forum free consultations doctor - .

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Additional Information:

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

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

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

In some cases, the electrocardiogram cannot find the conditions described for determining electrical position hearts. In this case, they speak of an uncertain position of the heart.

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

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

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

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

The 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 lowers and the heart takes a more vertical position in chest what is usual accompanied by vertical displacement of the EOS(to the right). In patients with pulmonary emphysema, an anatomically vertical position of the heart and an electrically vertical average electrical axis of the complex are usually observed. QRS. On the contrary, when you exhale, the diaphragm rises and the heart takes a more horizontal position in the chest, which is usually accompanied by horizontal displacement of the EOS(left).

Effect of direction of ventricular depolarization

Can be confirmed in case of incomplete blockade of the anterior branch of the left ventricle, when the propagation of impulses along the upper left parts of the left ventricle is disrupted and the average electrical axis of the complex QRS deviated to the left (see section “Impaired intraventricular conduction”). On the contrary, with pancreatic hypertrophy it is deviated to the right.

How to recognize EOS deviation to the right and left

Axis deviation to the right

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

cardiography.ru

Conducting system of the heart and why is it important for determining EOS?

The conduction system of the heart consists of sections of the heart muscle consisting of 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 impulse travels to the atrioventricular node and further along the His bundle. This bundle passes through the interventricular septum, where it divides into the right, heading towards the right ventricle, and the left legs. The left bundle branch 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 bundle branch is located in the middle and lower third of the interventricular septum, the posterolateral and inferior wall of the left ventricle. We can say that the posterior branch is located slightly to the left of the anterior one.

The myocardial conduction system is a powerful source of electrical impulses, which means that electrical changes occur in it first in the heart, preceding heart rate. If there are disturbances in this system, the electrical axis of the heart can significantly change its position, which will be discussed below.

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 overall stronger, and EOS will be directed specifically at it. If we project the position of the heart on the coordinate system, the left ventricle will be in the area +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 heart axis is found in tall, thin people - asthenics.
• Horizontal position of the EOS It is 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 they are intermediate body types, therefore the electrical axis can have an intermediate value (semi-horizontal and semi-vertical).

All five position options (normal, horizontal, semi-horizontal, vertical and semi-vertical) occur in healthy people and are not pathological.

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

Turns the heart around longitudinal axis help determine the position of the organ in space and, in some cases, are additional parameter when diagnosing diseases.

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

When can the position of the EOS indicate heart disease?

The position of the EOS itself is not a diagnosis. However There are a number of diseases in which there is a displacement of the heart axis. Significant changes in the position of the EOS result from:

1. Cardiac ischemia.
2. Cardiomyopathies of various origins (especially dilated cardiomyopathy).
3. Chronic heart failure.
4. Congenital anomalies of the heart structure.

EOS deviations to the left

Thus, deviation of the electrical axis of the heart to the left may indicate left ventricular hypertrophy (LVH), i.e. increasing it in size, which is also not independent disease, but may indicate left ventricular overload. This condition often occurs during 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 mass of the ventricular muscles increases, which leads to its hypertrophy. Ischemic disease, chronic heart failure, and cardiomyopathies also cause left ventricular hypertrophy.

In addition, LVH develops when the valve apparatus of the left ventricle is damaged. This condition is caused by stenosis of the aortic mouth, in which the ejection of blood from the left ventricle is difficult, and 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 common acquired heart defects are a consequence of previous rheumatic fever. Left ventricular hypertrophy is found in professional athletes. In this case, consultation is necessary sports doctor highly qualified to resolve the issue of the possibility of continuing sports activities.

Also, the EOS can be deviated to the left in case of intraventricular conduction disturbances and various blockades hearts. Deviation el. the axis of the heart to the left, together with a number of other ECG signs, is one of the indicators of blockade of the anterior branch of the left bundle branch.

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 pulmonary hypertension, such as bronchial asthma, chronic obstructive pulmonary disease over a long period of time cause hypertrophy. Pulmonary stenosis and tricuspid valve insufficiency lead to right ventricular hypertrophy. As in the case of the left ventricle, RVH is caused by coronary disease heart disease, chronic heart failure and cardiomyopathies. Deviation of the EOS to the right occurs with complete blockade of the posterior branch of the left bundle branch.

What to do if EOS displacement 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 diagnosing a particular disease. When the heart axis is deviated beyond the limits normal values(from 0 to +90 degrees), consultation with a cardiologist and a number of studies are required.

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

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

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Normal values ​​and causes of violation

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

In a healthy state, the electrical axis shifts to the left when following conditions :

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

Shift indicator to the right in the absence of pathology is observed in such situations:

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

Diagnosis using 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 angle 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 algebraic sum of 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, take into account the positive or negative meaning has a specific tooth.

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

Visual definition

Simpler and visual way to determine 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 we speak of an R-type ventricular complex. If on the contrary, 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 of the 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 that lead to the development of the disease. Deviation of the electrical axis to the left indicates the following violations:

• an increase in the size of the left ventricle - hypertrophy (LVH);
• malfunction of the left ventricular valves, which causes the ventricle to be overloaded with blood volume;
• cardiac blockades, for example, blockade of the left bundle branch (on the ECG this looks like this, which you can learn about from another article);
• disturbances in electrical conductivity inside the left ventricle.

Diseases that are accompanied by levogram

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

• coronary heart disease (CHD);
• cardiopathy of various origins;
• chronic heart failure (CHF) of the left ventricular type;
• congenital heart defects;
• myocardial infarction;
• infectious damage to the myocardium.

In addition to diseases, blockage of the conduction system of the heart can result from taking certain medicines.

Additional Research

The detection of a deviation of the EOS to the left side on the cardiogram is not in itself the basis for the doctor’s final conclusion. 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. Using ultrasound, the degree of ventricular hypertrophy and disturbances in their contractile function are assessed.
• 24-hour Holter ECG monitoring. The cardiogram is taken within 24 hours. Prescribed in cases of rhythm disturbance, which is accompanied by deviation of the EOS.
• X-ray examination chest. With significant hypertrophy of myocardial tissue, an increase in the cardiac shadow in the image is observed.
• Coronary artery angiography (CAG). Allows you to determine the degree of damage to the coronary arteries with diagnosed ischemic disease.
• Echocardioscopy. Allows targeted determination of the condition of the patient’s ventricles and atria.

Treatment

Deviation of the electrical axis of the heart to the left from the normal position is not in itself a disease. This is a sign determined using instrumental research, which allows you to identify disturbances in the functioning of the heart muscle.

Ischemia, heart failure and some cardiopathy are treated with medications. Additional diet and healthy image life leads to normalization of the patient's condition.

IN severe cases required surgery , for example, with congenital or acquired heart defects. At severe violation conduction system may require transplantation of a pacemaker, which will send signals directly to the myocardium and cause it to contract.

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

Detection of a 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 identifying the cause of this condition. Annual planned activities Electrocardiography allows for timely detection of disturbances in the functioning of the heart and immediate initiation of therapy.

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Axis location

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

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

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

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

The doctor may make the following conclusion:

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

All these conclusions are the norm.

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

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

Reasons for rejection

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

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

Diseases that cause hypertrophy are:

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

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

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

This pathology can be caused by the following diseases:

As well as diseases characteristic of LV hypertrophy:

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

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

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

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

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

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

If cardiac symptoms occur, you should immediately undergo electrocardiography.

Determination of ECG signs

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

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

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

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

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

Blockade of the anterior and posterior branches 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 widened and its apex is jagged. Near the high R wave there is a negative T wave.

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

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