Complete heart block of the left bundle branch: concept, signs, causes and treatment. Left heart block Transient complete left bundle branch block

Fedorov Leonid Grigorievich

Incomplete right bundle branch block is a fairly common problem. It can be detected during electrocardiography. The problem arises under the influence of congenital or acquired pathologies and requires timely diagnosis. This will avoid deterioration.

Organ description

Contraction of the muscles of the heart is provided by the conducting system. It includes sinus and atrioventricular nodes, a bundle of His and Purkinje fibers.

The bundle of His consists of the right and left legs. They provide the advancement of electrical signals to the tissues of the ventricles. If a blockade is diagnosed, this indicates that the signals through it do not pass completely or do not arrive at all.

In this case, excitement normally passes only along the left leg, which contributes to depolarization of the ventricles.

If a partial block develops, then the electrical signal is not transmitted along one leg. This condition does not pose a danger to the patient's life. Conductivity of the heart in this situation slows down. Similar processes can be detected in people who do not have health problems. Therefore, the problem is often viewed as a variant of the norm.

A great danger is a violation of the impulse conduction along the left leg, as this contributes to heart failure.

Pathology is most often diagnosed in men. Older women are more likely to suffer from left leg blockade.

Often the conduction of impulses slows down in childhood. If pathologies of the heart, respiratory and circulatory systems are absent, then this condition is not dangerous.

Although the disease most often proceeds without the slightest manifestation, it gradually disrupts the work of the ventricles.

Causes

Incomplete right leg blockade can occur under the influence of many diseases. Most scientists are inclined to believe that such disorders are not associated with a hereditary predisposition. Although in the presence of pathologies of the heart and blood vessels in close relatives, the likelihood of their development increases significantly.

Violation of conduction along the right leg occurs in different cases:

• with ischemic disorders in the heart;
• as a result of tumor processes;
• with anomalies in the development of the organ;
• with inflammatory processes in the endocardium or myocardium;
• if one pulmonary artery is blocked;
• at;
• if the prolonged course of hypertension has led to an increase in the heart;
• with pathologies in the respiratory system, which led to the appearance of cor pulmonale;
• after a heart attack;
• under the influence of bad habits;
• with constant emotional stress.

The electrical impulse is transmitted more slowly than it should if the person has taken large doses.

Incomplete right bundle branch block occurs when the vagus nerve is overexcited. This happens if a person is exposed to excessive physical exertion.

Blockages also develop if heart disease has been surgically treated.

Symptoms

Most often, when the electrical signal does not fully travel along the right leg, the person does not notice any symptoms. Determine the problems in the process of the planned passage of electrocardiography.

Patients may feel signs of an underlying pathology that has impaired cardiac conduction. Wherein:

• difficulty breathing
• soreness periodically appears in the chest;
• the rhythm of heart contractions is upset.

Therefore, the therapy of such diseases should be carried out on time.

But, if the signal is blocked completely:

When such violations appear, an urgent examination should be made, as this can occur with dangerous chronic diseases.

Although, with incomplete blockade, healthy people do not need specific therapy, since this condition is considered quite normal.

Establishing diagnosis

If you do not carry out diagnostic procedures, then the appropriate treatment option cannot be selected. Complete or even partial disruption of the advancement of the electrical signal leads to the fact that the number of ventricular contractions decreases. To confirm such changes, electrocardiography is performed and the blood is examined for hormones.

Incomplete blockade of the right bundle of His bundle on the ECG is manifested by a delayed passage of an electrical signal. In this case, there is a tooth showing contraction of the atria, but the tooth characteristic of a contraction of the ventricle is absent. This disorder is characterized by the appearance of small notches on the S wave and changes appear on the right.

If a person suffers from partial obstruction, then the QRS complex has a normal duration, but sometimes reaches 1, 1 second.

To identify pathological conditions that can disrupt the movement of the impulse, the patient must additionally undergo procedures in the form of:

Blockade of the anterior branch of the left bundle branch is considered one of the most common disorders that interfere with the normal conduction of the heart. In this case, electrical impulses cease to be conducted, but not in the back of the muscle, but in the anterior and anterolateral. The emergence of excitement begins in both the left and right bundle branch. In the first case, it goes from the back wall, and in the second - from the side and front.

This disease affects people in the age range from 55 years, but among those who have had a heart attack there are 15% of those who are at risk.

Causes of pathology

The disease does not appear on its own and only accompanies those pathologies that are already in the body. It can be:

Of course, there is also a risk group, which is characterized by an increased possibility of developing such a serious pathology. This traditionally includes people with obesity and diabetes, as well as a number of specific diseases: atopic myotonia, hemochromatosis, amyloidosis, hyperkalemia, collagenosis, sarcoidosis of heart tissue, degeneration in a progressive course.
According to the data, up to 75% of all those who have entered the stage of old age suffer from this disease.

Diagnosis and symptoms

Symptoms that would signal the onset of the development of the disease do not exist. That is why at the initial stages, deviations are rarely detected. Sometimes the manifestation of arrhythmia is possible, but doctors do not associate it with this pathology, since there are too many reasons for which it can occur. Most often, the symptomatology completely coincides with the disease that a person suffers without having any pronounced independent signs.

Important! You can prevent such a serious problem if you are regularly examined and, in particular, do an electrocardiogram. In this case, the presence of any abnormalities, including on the back wall of the heart muscle, will be detected on time.

Diagnosis is carried out by means of an ECG, which usually reveals an emerging deviation on the QRS axis to the left. In this case, the S and R waves are very pronounced. Diagnostics is not limited only to an ECG, since this will not allow to determine either the type of disease and the focus of occurrence, nor, of course, prescribe treatment. Therefore, MRI, as well as other deeper studies, can be prescribed as additional techniques.

Sometimes the block may be incomplete, and then it is displayed on the ECG. So, in the region of 40-60 degrees, the alpha angle is located. An intermediate position is noticeable in diagnostics. A sharp displacement of the axis is already considered a violation of electrical conductivity, and with the help of additional measures, it is ultimately clarified which factor is the deviation.

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The reasons for the development of pathology

Blockade of the anterior branch of the left branch of the bundle branch most often develops against the background of the following diseases:

• Chronic ischemia of the heart with cardiosclerosis, which is localized in the septum between the ventricles;
• Myocardial infarction, localized in the left ventricle (especially on its anterior wall);


• Myocarditis or cardiomyopathy, which are caused by various factors;
• Hypertrophic changes in the walls of the left ventricle with sclerotic or dystrophic changes in the myocardium;
• Dilation of the left ventricle, which develops due to aortic valve insufficiency;
• Idiopathically isolated calcification and sclerosis of the cardiac conduction system;
• Any congenital heart disease (especially manifested by defects of the interventricular or interatrial septa);
• The condition can develop in people who have undergone surgery for diseases of the cardiovascular system, as well as in patients with obesity, diabetes mellitus, hemochromatosis, sarcoidosis of cardiac tissues, atopic myotopy, collagenoses, hyperkalemia, progressive dystrophy, amyloidosis.

Statistics show that the disease can be found in almost 75% of elderly people, sometimes it is the only symptom of various myocardial diseases.

Symptoms and diagnosis of the disease

In most cases, the symptoms of blockade of the anterior branch of the left bundle branch are not manifested, and the disease is asymptomatic. Pathology can be diagnosed using an electrocardiogram - with pathology, there is a shift in the electrical axis of the QRS to the left of the normal side, and pronounced R (up) and S (down) waves. However, with the help of an ECG, it is impossible to determine the place of occurrence of a conduction disorder.

In very rare cases, the disease manifests itself as arrhythmia, but this is not the main factor in diagnosing the disease. The main symptoms almost completely coincide with the symptoms of the underlying disease and do not require differential diagnosis.

Treatment and prognosis of the disease

A specific treatment for blockade of the anterior branch of the left bundle branch has not been developed. A patient with this diagnosis most often does not need hospitalization. Patients whose electrocardiogram confirms the deviation of the left axis, if necessary, are prescribed therapy for the underlying disease that provoked the development of such a pathology. The treatment plan is developed individually.

The prognosis of LBBB blockade is favorable if its development is not associated with organic heart disease. In other cases, recovery depends on the disease, against which the pathology develops. It has been proven, despite the fact that treatment is not carried out, this pathology does not affect heart rhythm disturbances and mortality of patients.

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Anatomical aspects

To understand what this is a blockade of the anterior and posterior branches of the left bundle branch, you need to know about the conducting system and its main properties.

The main functions of myocardial cells are considered the ability to be excited, conduct nerve impulses and contract. Due to this, normal blood flow, tissue and organ nutrition with oxygen is carried out. These processes are closely interconnected.

The correct contraction of the heart is ensured by the continuous flow of nerve impulses through various structures. It goes from top to bottom.

This is provided by the conducting system, most of which is represented by the trunk of the His. It is located in the thickness of the interventricular septum.

Consists of two legs - left and right. The first has branching into the front and back. They go to the corresponding walls of the ventricles.

The branches of the left bundle branch end in the myocardium with Purkinje fibers. The path of the nerve impulse is carried out along these structures.

Blocks of the left bundle branch of His and its branches are called slowing down or lack of conduction of excitation along one or two branches. The consequence is a disturbed sequence of the path of the nerve impulse.

The excitement will first cover the interventricular septum. Then, along the unchanged right leg of the bundle of His ( PNPG) will reach the ventricle. This is normal.

The ventricle blocked on the left is excited in the last turn due to impulses from Purkinje fibers and an undisturbed branch of the His bundle. This is reflected in the electrocardiogram accordingly.

Classification

Left bundle branch block is divided into 2 large groups:

1. Complete.
2. Partial:
3. blockade of the anterior superior branch (PVLNPG);
4. posterior branch blockade (ZVLNPG).

They differ among themselves by the criteria for the ECG. Complete blockade of LPH is a prognostically unfavorable sign.

Also important is the classification by the duration of the blockade:

• constant;
• periodic (transient).

In the second case, it is considered as temporary ischemia (malnutrition of the heart muscle). Such patients undergo a thorough examination to select the most effective treatment.

Etiological factors

There are many reasons that can cause the appearance of conduction disorders on the cardiogram. The most common ones are as follows:

1. Various forms of ischemic disease - exertional angina, postinfarction cardiosclerosis.
2. Acute coronary syndrome with or without ST segment elevation (large and small focal myocardial infarctions).
3. Congenital heart defects.
4. Cardiomyopathy: dilated, due to physical stress, hypertrophic.


5. Acute toxic effects.
6. Acquired heart defects due to rheumatic fever (CRHD) or infective endocarditis.
7. Various types of cardiac arrhythmias.
8. Malignant arterial hypertension.
9. Some autoimmune diseases: ankylosing spondylitis, vasculitis, coronaritis.
10. Pericarditis.
11. Viral infections, accompanied by myocardial damage - cytomegalovirus, poliomyelitis, coxsackie, rubella.
12. Diffuse connective tissue diseases.
13. Spongy myocardium syndrome.
14. Chronic cor pulmonale.
15. Severe electrolyte and metabolic disorders, for example, in end-stage chronic renal failure.
16. Oncological processes.
17. Long-term and uncontrolled intake of serious drugs - diuretics, antiarrhythmics.
18. Injuries and trauma to the heart.

The result of these diseases is the defeat of the upper branching of the left branch of the bundle of His or the entire trunk, which determines the diagnostic picture.

Symptoms

Blockade of the anterior branch of the left bundle branch is not a disease. They are her consequence. Therefore, there are no complaints characteristic of a violation of conduction in the heart. All symptoms of the patient are due to the underlying disease. However, such a cohort of patients always notes:

• recurrent pain or discomfort in the left side of the chest;
• dizziness;
• general weakness;
• shortness of breath of varying severity;
• interruptions in the work of the heart or palpitations.

Fainting is common in patients with new-onset complete blockade of LDLH.

Diagnostics

Revealing of lesions of the His trunk occurs only when performing an ECG in 12 standard leads. The changes are due to a disturbed arousal pathway. Each type of blockade has its own distinctive features.

Signs of complete blockade of LNBH on the cardiogram are:

1. M-shaped QRS complexes in I, aVL, V5, V6 leads.
2. Deviation of the electrical axis of the heart to the right.
3. The increase in the QRS complex is more than 0.12 s.
4. Changes in V1, V2, III, aVF leads.

Blockade of the anterior branch of the left bundle branch of His on the ECG is accompanied by certain signs:

1. Changing the direction of the electrical axis of the heart (position sharply to the left).
2. There is no expansion of the ventricular complex.

If BZVLNPG takes place, then the following changes are recorded:

1. The electrical axis of the heart is deflected to the right.
2. The QRS complex is of normal size, no deformation is observed.

These signs of blockade are indicated by the doctor when decoding the cardiogram, which allows a faster diagnosis. In conclusion, the width of the complexes, the average value of the heart rate and all the identified changes are entered.

Ultrasound of the heart with blockade of the left anterior and posterior branches is of secondary importance. It allows you to determine the underlying disease that caused the conduction disorders.

Diagnosis of myocardial infarction is considered a difficult task in the case of registered complete left leg blockade, since it "hides" the cardiographic criteria.
Holter study - daily ECG monitoring shows a permanent, periodic type of complete or incomplete blockade. In the second case, you can find out the cause of its occurrence.

During the examination, the patient keeps a diary where he writes down his daily manipulations.

BPVLNPG is often recorded during physical and emotional stress. Holter research is important for the detection of various arrhythmias against the background of changes in conductivity.

Therapy

Any LPH blockade detected for the first time requires hospitalization in a specialized department. Changes do not require special treatment, but careful diagnosis is necessary.

It should be noted that the first complete LBBB, which is accompanied by pain in the heart, is regarded as an emergency pathology.

Such patients are hospitalized in the intensive care unit or intensive care unit. Treatment in these cases is similar to that for acute myocardial infarction!

In other cases, the management of patients is reduced to the treatment of the underlying disease, the prevention of its complications.

Knowing what an LBH blockade is, one can understand that it does not pose a serious health hazard. However, it always requires a thorough examination of the patient to identify cardiac pathology and the selection of rational treatment.

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If on your ECG doctors saw a blockade of the bundle branch, this means that you have problems with the performance of the ventricles of the heart. The legs of the His bundle are an element of the neuro-electrical excitation of the heart muscles. I write in simple words, as medical terms are quite abstruse.

The bundle of His is subdivided into two front legs (left and right) and one back (thick), from which, in fact, two front ones branch off. Moreover, first the right front leg departs, and just below the left front leg-branch.

The very structure of the branches suggests that there are one, two, and also three-beam blockades. Let us first consider single-beam ones.

Right bundle branch block

Single-beam blockade refers to the blockade of the right bundle branch (see upper figure). It rarely manifests itself in those who do not have any kind of heart disease. The problem indicates electrolyte disturbances.

Effects

With a complete blockade of the right bundle of His bundle, the right ventricle contracts not due to nerve impulses coming from the right pedicle, but due to those that break through from the left ventricles. The work of the ventricle, therefore, on the ECG looks like in the figure.

Causes

It occurs against the background of myocardial infarction, and other heart problems.

Effects

The anterior-lateral wall of the left ventricle suffers. The impulse arrives at the left rear wall. On the ECG, it looks like this:

Blockade of the posterior branch of the left bundle branch

Causes

It also develops against the background of heart attacks, cardiomyopathies, calcifications of the conducting cardiac systems.

Effects

With a complete blockade of the left bundle branch block, the impulse does not pass through the main trunk. The right ventricle works, and from it, the impulse enters the left ventricle, forcing it to contract, but with some delay.

With incomplete blockade of the left bundle branch block, there is only a slight slowdown in the passage of the electrical impulse. But all the same there is a delay, which is visible on the ECG.

Now let's look at two-beam blockades.

Blockade of the anterior left and posterior left branches of the His bundle

Causes

Aortic heart defects, cardiosclerosis.

Effects

The passage of impulses along the front left and rear left legs is blocked. The impulses go through the right leg, from the right ventricle. The activation time of the left ventricle is increased.

There are also blockades of the right leg and left anterior branch of the His bundle or the right pedicle and the left posterior branch of the His bundle.

But the blockade of the right leg and the left anterior branch of the His bundle is the most common option.

Three-beam blockades

Causes

Arterial hypertension, AMI, IHD, Lenegra's disease.

Effects

If the block is incomplete, then the weakened impulse passes along the least affected branch to the ventricles from the atria. And individual impulses may not pass at all. This is a difficult and difficult case.

Who is the first to suffer from bundle branch block?

Nervously excitable people who take all situations "to heart". May develop in people with cardiosclerosis who have had myocardial infarction.

What is contraindicated

Hard physical labor is contraindicated for people with blockages. You should protect yourself from heavy loads. Well, you shouldn't be nervous either. All this will negatively affect the work of the heart.

Heart Tincture Treatment

You can drink infusions and teas that improve heart function. You can also create an effective tincture from pharmacy ingredients and drink it.

Mix the tinctures: valerian - 30 ml, peony - 80 ml, motherwort - 40 ml, hawthorn - 50 ml, mint - 20 ml, calendula - 20 ml.

Drink should be 1-10 drops, diluted in a tablespoon of water three times a day. Start with 1 drop per table. spoon of water, add 1 drop every day, and so on up to 10 drops at a time.

The course of taking the tincture is 2 months. Then a break for 3 weeks and another 2 months for a second course.

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The formation of ideas about the blockade of the branches of LBBB (half-block) was an important step in the study of the mechanisms of AV block progression, since this made it possible to identify the involvement of LBBB in the presence of RBBB (bifascicular, or two-bundle, blockade). First, such patients (with two-beam blockade) were prophylactically implanted with pacemakers, which is currently considered unjustified in the absence of an obvious three-beam blockade. Blocks of branching of LNBP (half-block) were originally described in experiments on dogs, in which LBB is divided into two rather clearly defined bundles. In humans, LBB is more likely to divide in a fan-like manner along the left ventricular surface of the IVS, forming two distinct bundles. For this reason, typical changes in ECG data are similar, although not necessarily caused by a discrete lesion of a single, clearly differentiated beam.

The main changes to which the two-beam blockade leads are the delay in the onset of excitation of the myocardium, activated by the damaged beam, which, as in BNBG, upon activation, forms a higher-amplitude vector. The delay in the onset of myocardial excitation is not very large (≤20 ms), since excitation rapidly spreads through the Purkinje network from the intact bundle to the area blocked distal to the blockade site. Two-beam blockages lead to a slight expansion of the QRS complex (≤110 ms), but the QRS axis is significantly displaced towards the block. Semi-blocks also change the direction of the start vectors. Understanding the anatomy helps explain the electrical axis deviation.

Blockade of anterosuperior branching of the left bundle branch

The blockade of anterosuperior branching of LBB displaces the initial vectors (in the first 0-20 ms) downward and to the right due to the absence of early activation of the anterior-superior LV papillary muscle. As a result, q waves are recorded in leads I and aVL, and r waves are recorded in leads II, III and aVF. The downward displacement of the electrical axis may be sufficient to explain the small q waves in the right chest leads that are recorded high enough in the fourth intercostal space (Fig. 1). The cardinal sign of blockade of the anterior branch of LPH is a shift of the electrical axis of the QRS to -45-60 ° due to a change in the direction of vector 2 to the left and up. The QRS complex has a qR shape in leads I, aVL and rS - in leads II, III and aVF. In the chest leads, significant clockwise rotation with S waves in leads V5 and V6 is most often recorded, just as in cases of shift of the final QRS vectors to the right, but without the formation of an S wave in leads I and aVL. The S waves in leads V5-V6 are formed due to a significant upward shift in the direction of vector 2, which can even be directed oppositely to leads V5 and V6, despite the shift to the left (see Fig. 1). Recording leads V5 and V6 in the fourth intercostal space (instead of the usual position in the fifth) reduces the amplitude or leads to the disappearance of the S wave. The duration of the QRS complex is slightly increased to ≤110 ms, sometimes with a slight splitting of the terminal part. Blockade of the anterior branch of LBBH is not accompanied by secondary ST or T.

Fig. 1. Schematic and electrocardiographic reflection of the changes caused by the blockade of the anterior branch of the left bundle branch. The chest is presented in the frontal (A), horizontal (B) and left lateral (C) planes. Heart slices obtained by MRI are inserted into the figures to indicate the anatomical position (B). Offset vector 2 defining the axis of the QRS complex is shown in red. It is important to note that in the left lateral projection, the relatively high position of the V1 and V2 electrodes can be the cause of the initial q wave even in the case of the forward vector 1 (yellow). Also noteworthy is the fact that upward vector 2 can form a negative phase of the QRS complex in lead V6 as a result of its relatively low location. For a more detailed explanation, see the text.

Differential diagnosis of blockade of the anterior branch of LPH is carried out between clockwise rotation of the heart due to various conditions: an increase in the pancreas, positional changes or deformities of the chest. The presence of pronounced S waves in leads I and aVL is characteristic of clockwise rotation of the heart and makes it possible to distinguish between these two conditions. The clinical significance of isolated blockade of the anterior branch of LBB is very small, even in the presence of lengthening of the H-V interval (His bundle - Purkinje fibers).

Posterior inferior branching block of the left bundle branch

Isolated blockade of the posterior inferior bifurcation of LBBB is a rare condition often diagnosed in combination with RBBB. ECG diagnosis of this blockade is difficult and is more based on clinical data. The main sign of the blockade of the posterior-inferior branching of LPBH is the shift of the electrical axis of the QRS to the right up to + 100-120 °, which can also be observed in healthy people, especially at a young age, as well as in the case of an increase in the pancreas or deformation of the chest. All of these conditions must be ruled out before a diagnosis of a blockade of the posterior-inferior branching of LPHB is established.

Changes in the QRS complex caused by the blockade of the posterior-inferior branching of LBBH are almost a mirror image of the signs observed with the blockade of the antero-superior branch of LBBH (Fig. 2). The initial vector (vector 1) is displaced upward, since the "lower component", normally formed upon excitation of the posteroinferior papillary muscle, is absent. On the ECG, this is reflected by the q waves appearing in the inferior leads (II, III and aVF). Delayed excitation of the posterior LV wall shifts vector 2 down and to the right, which leads to a shift in the angle of the electric axis of the QRS to the right and a change in the shape of the complex in leads II, III and aVF by qR. There are no characteristic changes in the chest leads.

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Incomplete right bundle branch block - is it a "technical" diagnosis or a disease?

Such an unusual name for the diagnosis attracts, most likely, the word "blockade". In itself, this, of course, is alarming, but does not say anything concrete to a layman. In order to understand the meaning of this complex term, one must recall such an unusual anatomical structure as the cardiac conduction system.

This formation is designed to correctly distribute the impulses that go down from the sinus node. The conduction system of the human heart is responsible for the correct and synchronous contraction of the atria and ventricles. It is clear that the heart is a pump that "drives blood in one direction."

The general direction of the blood is as follows:

• from the left ventricle, blood is released into the aorta, the largest artery in the body;
• then, through the system of branching arteries of a smaller caliber, the blood enters the capillaries, while the speed of its flow slows down;
• gas exchange occurs in the capillaries, and the process of tissue respiration is realized: oxygen is given to the tissues, and carbon dioxide is taken;
• then, through the venous vessels of increasing caliber, the blood enters the vena cava system and ends up in the right atrium, which is the main "collector" of venous blood;
• from the right atrium, blood is sent to the right ventricle, and from there to the lungs, to enrich venous blood with oxygen and turn it into scarlet, arterial blood.

A bundle of His - what is it and why is it needed?

As you can see, arterial and venous blood in our heart does not mix, and the chambers of the heart contract strictly synchronously: at first there is a systole of the ventricles, and the atria at this time "rest", filling with blood. Then the ventricles during diastole are filled with blood, which is released from the atria.

For the normal contraction of the heart, it is necessary that the atria contract together, like the ventricles, in pairs. And there must be strict synchronicity between them.

In the event that such a synchronous contraction does not occur, then various options for the appearance of pathology of the electrical impulse are possible, which are called blockades. These conditions can be life threatening.

It is known that a special conduction system is located in the heart tissue, in the form of special bundles of nerve cells. They form nodes and bundles that help conduct impulse from the overlying parts of the heart to the underlying ones. There are patterns of impulse conduction, and there is a strict order.

One of these bundles is the bundle of His, which is otherwise referred to as the atrio-ventricular bundle. It passes in the thickness of the interventricular septum, and splits there into two legs - on the left and right. As the name suggests, the right leg approaches the right ventricle, and the left leg approaches the left ventricular myocardium.

These legs end with special Purkinje fibers, which branch out in the muscle tissue of the corresponding ventricles. The pulse is carried out through the structures of the His bundle at different speeds, which is, on average, 1-3 meters per second, which is quite noticeable with a bundle length of 15-18 mm.

In addition to arrhythmias, blockages of impulse conduction to the underlying parts of the heart can often be detected if, for some reason, there is a complete or incomplete blockage of impulse conduction along one of the legs of this bundle. What is this pathology, and how does it manifest itself?

Incomplete right bundle branch block - what is it?

It is important to know that in addition to the His bundle, which is the main pathway for the impulse, in the myocardium there are also Kent's bundle, Mahaim fibers, and two "alternative tracts" - James and Bershenmanshe. All these pathways can serve as additional conduction pathways, therefore, with bundle blockages, the heart still contracts, nothing terrible happens.

Clinically, this is manifested by the presence of a syndrome of intraventricular blockade, or by slowing down or stopping the conduction of an electrical impulse to the right ventricular myocardium. This occurs when there is a violation of the conduction of the right leg.

If we are talking about an incomplete blockade of the right leg, then this indicates that the impulse is passing, but its conduction is slowed down. In the event that the impulse does not pass at all to the myocardial site, then they speak of a complete blockade. In this case, the right ventricle is still excited and contracted, the person lives, and may not experience any unpleasant sensations.

Just the excitation of the right ventricle begins in a roundabout way. In other words, the wave of depolarization comes through the left ventricle, and the left half (lying on the other side) of the interventricular septum.

The causes of the blockade

It is known that various signs of incomplete blockade of the right bundle branch block, determined by ECG, are found in perfectly healthy people, more often in men who do not make any complaints. The incidence of this pathology in the population is quite high - 1-2% of the total population.

If we talk about a complete blockade of the right leg, then it occurs in recruits on average, in 0.2% of all cases, and over the age of 40, this figure rises to 5%. This means that every 20 adult male has some or other signs of a conduction disorder.

With regard to diseases, the complete blockade is caused by diseases in which an overload of the right heart can occur. These include:

• Chronic cor pulmonale (this is a condition in which blood circulation in the lungs is obstructed and the preload on the right side of the heart is increased). This condition develops with lung diseases: pneumosclerosis, and many other diseases;
• Ischemic heart disease (IHD) of the heart, or, especially when combined with arterial hypertension, or (hypertension);
• In acute and often with posterior diaphragmatic or apical localization of the necrosis zone;
• Sometimes a complete blockage occurs in completely healthy people, but this is rare. Much more often in healthy people, incomplete conduction disturbances are detected.

If we talk about an incomplete blockade, then exactly the same reasons lead to it, and diseases, only occurring in a "milder" form. In old age, these are all sorts of myocarditis, cardiosclerosis, chronic myocardial ischemia.

One of the important causes of incomplete conduction disturbances is the development of myocardial hypertrophy. In this case, the deceleration of the impulse conduction occurs because there is simply "a lot" of myocardium, and therefore the impulse seems to pass slowly.

This situation can develop in people with a sports heart, as well as in people with pulmonary hypertension, because it is in them that the myocardium of the right ventricle should be stronger.

In some cases, incomplete blocking of the impulses of the right leg develops with an overdose of cardiac glycosides and beta-blockers, with treatment with certain antiarrhythmic drugs, for example, quinidine, as well as with severe dehydration (with intestinal infections).

How dangerous is an incomplete right bundle branch block? The prognosis for this condition is not determined at all by this formulation of the diagnosis. As mentioned above, the degree of development of the underlying disease is of decisive importance, as well as the presence of the risk of developing a complete atrioventricular block (in which the atria and ventricles can contract each in their own rhythm, disorganized).

• It is the latter fact that can lead to the development of ventricular arrhythmias.

It should be noted that the blockade, especially incomplete, does not mean the automatic presence of arrhythmia. Simply, in the presence of predisposing and unfavorable factors, this can happen, and then the blockade of the leg, albeit incomplete, can increase the risk of sudden cardiac death.

So, the probability of the appearance of a complete atrioventricular block in persons with partial violations of the conduction of the legs of the bundle of His is 1% per year.

Of course, this figure takes into account conditions in which there is a pronounced cardiac pathology. It is in the presence of an AV block that treatment will already be required, which may consist in the installation of a pacemaker.

How does the blockade manifest?

Incomplete blockade of the right bundle branch block may not affect the heart in any way. In all clinical guidelines it is said that if the blockade has not reached the state of tricuscularity, then it does not manifest itself in any way. That is, in order for any manifestations of the blockade itself to arise (provided that there is no organic disease), it is necessary that immediately, jointly arise:

• left bundle branch block;
• complete or incomplete atrioventricular block.

In the overwhelming majority of cases, variants of incomplete conduction disturbance of only one leg (it does not matter, right or left) are a phenomenon that can only be determined on an ECG, for example, during examination during a medical examination.

In the same case, if the patient's CC has any heart disease, then the entire clinic is caused by the main complaints, for example, with emphysema or postinfarction cardiosclerosis, and the bundle branch block is a "small and secondary" diagnosis that practically does not play its own roles.

The only option in which you can suspect the presence of a blockade before the electrocardiography is the usual auscultation of the heart, or listening with a phonendoscope. The doctor may suspect this by ear if there is a splitting of tones that is not felt by the patient.

The next stage is the usual, routine, during which a special form of ventricular complexes in the first chest leads are determined, as well as a slight increase in the duration of the gastric QRS complex to 0.11 seconds. It is clear that this increase in time arises due to the "roundabout path", and the indirect following of the pulse along the blocked leg of the His bundle.

Holter monitoring is also shown, in which functional, or transient, variants of the development of the blockade can be identified. This can happen, for example, due to an overdose of certain medications while treating diseases.

In the event that the blockade of the leg occurs against the background of a cardiac disease, then an intracardiac electrophysiological study is performed. Its main task is to determine whether there are indications for the setting (implantation) of a permanent pacemaker.

Can I go in for sports and serve in the army?

With incomplete blockade of the right bundle branch block, sports are not contraindicated. Indeed, cardiologists are concerned about those conditions that increase the risk of sudden cardiac death, as well as various undiagnosed valvular defects, especially aortic stenosis, which, with an increase in the load on the heart, can lead to unpredictable complications.

Isolated and asymptomatic conduction disorders, especially at a young age, do not lead to a significant increase in complications. As a last resort, Holter monitoring can be performed, which will be carried out against the background of sports training.

If the analysis of the results does not reveal the progression of the volume of the blockade, the appearance of arrhythmia, or signs of a disorder of the atrioventricular connection, then there are no contraindications to sports events. It will only remain to pass an ECG annually in order to timely know the state of affairs with intraventricular conduction.

With regard to service in the armed forces, then, as we remember, in the absence of an unambiguous interpretation, the whole emphasis is on “dysfunction”. In this case, given the absence of pronounced organic damage and the asymptomatic course, such a young man will be drafted into the army under category B-4, that is, "fit with minor restrictions."

This actually means that he is unfit for the elite units of the RF Armed Forces, that is, where it is more or less prestigious to serve. As a result, it will be sent somewhere in the infantry, or in the signal troops, where, naturally, no restrictions will be observed, since the "automatic" determination of the type of troops will already serve as a guarantee that such restrictions have already been made.

About the treatment of right bundle branch block

As you probably already guessed, you need to treat only those blockade options in which there is an increased risk of cardiac death, or there is a pronounced desynchronization in the work of the upper (atrium) and lower (ventricles) parts of the heart. As a rule, in this case, we are talking about patients who have clinically significant and reliable signs of heart failure.

Such patients are usually hospitalized in the department of interventional cardiac surgery and arrhythmology, or in the diagnostic department of a cardiological hospital. Hospitalization is needed in order to:

• choose a good drug therapy if a diagnosed arrhythmia is observed against the background of a blockade;
• exclude acute myocardial infarction in the event of an acute blockade of the bundle branch (this is always suspicious, but, however, then the left leg is affected, not the right);
• conduct an electrophysiological intracardiac study;
• implant a pacemaker, or perform cardiac synchronization.

To reassure young people and their parents, it is safe to say that a pacemaker is not installed “just like that”. For this, there must be very strict indications, for example:

• Alternating blockade of the legs (when there is a "walking" violation of either the left or the right leg;
• Grade 3 atrioventricular block with syncope.
• Blockade of the legs, which has occurred with acute myocardial infarction;
• Severe heart failure of functional class 3 or 4, despite correct treatment.

Thus, it becomes clear that it is not the blockade of the right bundle branch block that is “treated”, but those conditions and diseases that it can aggravate or provoke.

In conclusion, it must be said that in order to avoid confusion and ambiguous interpretation, if there are signs of blockade during the ECG, it is advisable for the patient to undergo an ultrasound of the heart. Only then it will be possible to assess the thickness of the interventricular septum, and to conclude about the presence or absence of the right ventricle.

Only in this case, the diagnosis of blockade of any of the legs will have a real diagnostic value, since it will be exposed taking into account the presence or absence of myocardial hypertrophy.

His bundle branch block (BNBG) is a cardiac pathology, which is expressed in impaired intracardiac conduction, slowing down or complete cessation of conduction along the branches of the His bundle. Signs of incomplete right bundle branch block are usually absent at the initial stage of development. As the disease aggravates, a clinical picture will appear, which is characterized by weakness, dizziness, symptoms from the disruption of the cardiovascular system.

The blockade of the right and left bundle branch is diagnosed using instrumental research methods, and the most informative in this case is the cardiogram. Treatment of bundle branch blocks is prescribed on an individual basis. If conservative therapeutic measures do not give the desired result, then an operation is performed to install an artificial heart rate driver.

The prognosis, if the causes of the right bundle branch blockade do not have an organic cardiological basis, is favorable. In all other cases, the outcome of treatment will depend on the severity and form of the underlying factor. At the same time, it should be understood that if the blockade of the right bundle of His bundle in children or adults is not eliminated in a timely manner, this can lead to other pathological processes, and the risk of death also increases.

Etiology

The reasons for the development of such a disease can be divided into cardiac and non-cardiac.

The first group includes the following pathological factors:

• or ;
• dystrophic changes in the myocardium;
• coronary artery disease;
• idiopathic calcification;
• fibrotic changes in the legs of His;
• brugada syndrome;
• , including postinfarction forms;
• levy's disease;

At risk are people with a history of myocardial infarction.

As for the non-cardiac causes of the development of the pathological process, here it is necessary to highlight such factors as:

• excessive use of drugs, the action of which is aimed at the cardiovascular system;
• in severe form with frequent relapses;
• violation of the electrolyte balance in the body;
• alimentary obesity;
• chronic alcoholic illness;
• excessive drinking, smoking.

There are no age or sex restrictions: a transient or partial blockade can be diagnosed even in children.

Classification

This disease is classified according to several criteria: localization, nature and severity of the clinical picture.

By localization of the pathological process:

• incomplete right bundle branch block;
• complete blockade of the right bundle branch;
• incomplete left bundle branch block;
• complete blockade of the left bundle branch;
• blockade of the posterior branch of the left leg;
• blockade of the anterior branch of the left bundle branch.

According to the severity of the pathological process, the following forms are distinguished:

• single-beam - signal transmission is difficult along the right leg and partially on the left;
• two-bundle - the branches of the left leg are blocked, as well as the right leg with one of the branches of the left;
• three-beam - all three paths are affected simultaneously.

The stages of development of the pathological process are also distinguished:

• first degree - signals arrive with a delay;
• second degree - signals partially do not reach the organ;
• third degree - nerve signals do not reach the ventricular myocardium at all.

It should be noted that this disease is almost always a consequence of other pathological processes, therefore, when carrying out diagnostics, it is important not only to establish the form and severity, but also the underlying factor.

Symptoms

Quite often, such a disease is asymptomatic, which leads to delayed diagnosis.

As a rule, the clinical picture manifests itself already in the late stages of development, characterized by the following clinical signs:

• pronounced shortness of breath even with minor physical exertion;
• the patient cannot stand the measure of physical activity that was previously acceptable to him;
• heart palpitations;
• unstable heart function;
• blood pressure surges;
• chest pain, feeling of tightness and discomfort;
• with auscultation, a change in heart sounds will be diagnosed.

Symptoms of a bundle branch block in the later stages of development are as follows:

• severe shortness of breath even at rest;
• extremely low heart rate - up to 40 beats per minute;
• dizziness, weakness;
• pallor of the skin;
• increased cold sweating;
• violation of the heart rhythm;
• loss of consciousness;
• in some cases of the skin.

In addition, it should be noted that the overall clinical picture will be supplemented by specific symptoms of the underlying factor. Therefore, self-medication in this case is impossible: this can lead to extremely negative consequences.

Diagnostics

In this case, instrumental analyzes are the fundamental methods for determining the disease.

The doctor prescribes:

• daily ECG monitoring;
• electrocardiography;
• transesophageal electrophysiological examination of the heart.

As for standard laboratory tests, they are carried out only if necessary - to determine the nature of the course of the underlying disease. By themselves, in this case, they are not of diagnostic value.

In addition to laboratory and instrumental diagnostic measures, the doctor conducts a physical examination of the patient, during which:

• finds out the complete clinical picture;
• collects personal and family history;
• examines the patient's medical history;
• finds out if the patient is taking any medications to relieve symptoms.

Comprehensive diagnostics allows you to accurately determine the shape, severity of the disease, as well as the etiological factor. Based on these data, further treatment tactics will be determined.

Treatment

Treatment of the pathology of the right bundle branch, if the underlying factor is absent, is not carried out. In this case, the doctor gives general recommendations, which can be followed to prevent the development of pathological processes.

In general, drug therapy can be based on the following drugs:

• antihypoxants;
• antioxidants;
• b vitamins;
• antiplatelet;
• hypolipidemic;
• vitamin and mineral complexes;
• sedatives.

In addition, in some cases, a diet can be additionally prescribed, and a specific dietary table is determined on an individual basis, based on the underlying factor.

In the event that drug therapy does not give the desired result or if there is a high risk of complications, an operation is performed - the patient is installed a special device that normalizes the conduction of excitation impulses. With AV block, a pacemaker can be installed, in which the heart will work correctly.

If the diagnosed violation does not have any clinical signs, does not affect the patient's well-being, then no specific treatment is carried out - dynamic observation is shown.

Possible complications

Despite the fact that in most cases this pathology has a favorable prognosis, in the absence of treatment, complications such as:

• acute heart failure;
• thromboembolism;
• violation of the heart rhythm;
• cardiac arrest and death.

It should also be taken into account that complications may develop from the underlying disease.

The prognosis, if there is no pathological basis, is favorable - the violation does not pose a threat to human life and does not impair the quality of life. If the cause of BNBH is a cardiac disease, everything will depend on the underlying factor.

Prevention

Unfortunately, there are no specific methods of prevention.

• eat right;
• exclude excessive consumption of alcoholic beverages, quit smoking;
• observe the work and rest schedule;
• include moderate physical activity in your schedule;
• take daily walks in the fresh air.

People who have a history of cardiovascular and systemic diseases need to undergo a systematic medical examination, to fully comply with all the recommendations of doctors. If you feel unwell, you should seek medical help, and not treat yourself.

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