Blockade of the bundle branch legs

bundle branch block - is malfunctioning cardiac activity due to partial or complete lack of momentum transfer pathways atrioventricular bundle lag provoking ventricular myocardium and is accompanied by changes in the electrocardiographic pattern.

In the structure of cardiovascular diseases accompanied by cardiac dysfunction, the blockade of the bundle of the bundle has a blockage of up to 2.5% of cases, among which the blockade of the anterior superior branch of the left branch of the bundle of His is a large proportion. Localization of this branch in the projection of the aortic valve ring promotes the development of blockade, due to the constant effect of increased pressure in the ventricular cavity, as well as the pathology of the aortic valve.

In the second place in the occurrence there is a blockade of the right leg of the bundle of His, which has no connection with any other cardiac pathology. The blockade of the posterior branching of the left branch of the bundle is uncommon, as isolated pathology, due to the fact that it is supplied from both the anterior and posterior descending coronary arteries. Recent scientific research has refuted the three-beam structure of the conducting pathways of the heart, although this concept is still used today for practical purposes. According to this theory, all possible intraventricular blockades are divided according to the principle of localization:

1. Blockage in the projection of one bundle:

* impairment of transmission of electric impulse along the anterior branch of the left foot of the atrioventricular bundle;

* blocking the transfer of the pulse along the posterior branch of the left foot of the atrioventricular bundle;

* violation of the conductivity function along the fibers of the right bundle of the bundle.

2. Blockage of both bundles:

* combined block( front upper branch of the left leg and right leg of the bundle of His);

* hemiblocade( the posterior lower branch of the left leg and the right leg of the bundle of His).

3. Blockade of three beams.

reasons bundle branch block

blockade in atrioventricular conduction system of the beam may occur against the background of well-being in healthy people( right bundle branch block), and be the result of an organic lesion of cardiac infarction. In some cases, the atrioventricular blockade is an accidental finding in ECG registration and becomes the reason for the patient's on-site examination for the presence of cardiac pathology.

Typically, disturbance of the electrical pulse is due to the presence of the hearth in the heart muscle with non-typical structure( necrosis, multiple sclerosis, myocardial defect), so in most cases resistant full bundle branch block are the result of organic disease of the heart muscle.

Among the causes of cardiac blockade leading position on the frequency of occurrence of bundle branch block belongs to: hypertension prone to crisis course, acute coronary insufficiency and transmurralny myocardial infarction, hypertrophic cardiomyopathy and dilatation forms, as well as the use of surgical treatment of heart disease.

The dependence of the onset of two-beam blockades and the patient's pathology of the aortic valve( congenital aortic defects), as well as coarctation of the aortic arch, was reliably proven.

Important in the appearance of the blockade is the state of electrolyte balance in the body. Thus, hyperkalemia and hypercalcemia with a combined decrease in the level of sodium in the blood can become a provocateur of the development of any form of disturbance of the rhythm of cardiac activity, including blockade of the legs of the bundle of His.

There is a separate type of blockade of the legs of the atrioventricular bundle of iatrogenic genesis( the appearance of signs of blockade after the application of separate groups of drugs - antiarrhythmic, diuretic drugs and cardiac glycosides).

major pathogenic mechanism for the development of disorders of impulse conduction pathways bundle branch block is the occurrence of focal lesions in the organic result of compression due to edema, necrosis followed sclerosis change excitability and duration of the refractory period, decrease the level of the potential on the membrane.

The blocks of fibers of the conductive bundle bundle are not accompanied by gross rhythm disturbances and unpleasant sensations in the patient, because the legs of the atrioventricular bundle are the drivers of the fourth order rhythm, that is, they are able to generate no more than 30 pulses per minute, in contrast toSinus-atrial node, generating up to 80 pulses for 1 minute. When this or that branching of the atrioventricular bundle is blocked, the pulses begin to be generated and propagate along the conductive paths of the Purkinje fibers with a slowed frequency up to 20 pulses per minute. These circumstances do not pose a threat to the life of the patient, but the prolonged course of the disease provokes irreversible changes in the brain, caused by a violation of the blood supply to the brain structures.

Symptoms of the blockade of the bundle of the bundle.

. Three types of blockades are distinguished along the course of the disease: persistent, transient( blockades alternate with unchanged intraventricular conduction) and alternating( ECG changes are determined for the blockade of one, then the second leg).

This form of cardiac rhythm disturbance refers to the category of intraventricular blockades, therefore it is not accompanied by gross disturbances of rhythm and heart rate. Patients suffering from blockage of the legs of the atrioventricular bundle, mostly present nonspecific complaints that do not allow to make a correct preliminary diagnosis during the initial examination of the patient: dizziness and short-term disturbances of consciousness, a feeling of shortness of breath, reduced efficiency and fast fatigue.

If a patient experiences a blockage of the left leg of the bundle of His, which develops against the background of the cardiovascular pathology, patients present complaints characteristic of certain nosological forms( cardialgia or typical attacks of angina, symptoms of heart failure).With percussion of the heart in such a situation, the expansion of cardiac dullness is determined, and the auscultative signs of blockade is the splitting of the II tone on the apex of the heart, which is dependent on the respiratory phases.

At laboratory examination of blood and urine there are no changes, only examination of the hormonal status allows to determine the extracardiac nature of the blockade of the bundle of the bundle.

Holter ECG monitoring is an obligatory instrumental method for examining a patient with suspected intragastric blockade. This method allows not only to determine the changes in ECG, characteristic of a particular form of blockade of the legs of the bundle, but also to record the clinical symptoms that arise in the patient at the time of the attack of the blockade. An indispensable condition for properly conducted Holter monitoring is the constant observation of the patient with their own sensations and the recording of all changes and the time of their occurrence. The maintenance of such a diary in some cases allows you to determine the cause of the blockade, the elimination of which helps prevent the development of a violation of the rhythm of the heart activity.

In a situation when ECG registration fails to reveal reliable symptoms of atrial-ventricular bundle blockade, the patient is shown to perform a transesophageal electrophysiological study that allows to assess the state of the conduction system of the heart.

Despite the absence of severe clinical symptoms, blockade of the bundle of the bundle does not always have a favorable course and in the situation of existing chronic cardiac pathology can be fatal.

Consequences of blockade of the bundle of the bundle are caused by complete blockade and characterized by the development of Morgagni-Adams-Stokes attacks. In order to prevent this condition, which is dangerous for the life and health of the patient, the patient is recommended the product of implantation of a pacemaker.

Blockade of the right leg of the bundle of the GIAS

. In the general structure of the incidence of blockade of the bundle of the bundle, the block of the right leg accounts for up to 4.5%, among which the majority of patients are men of elderly age suffering from coronary heart disease with episodes of acute coronary insufficiency.

Congenital etiological factors in the occurrence of blockade of the right foot of the atrioventricular bundle are the anomalies of the development of the fibers of the bundle of the bundle, as well as the disturbance of the normal position of the vessels. Acquired risk factors for chronic diseases of the heart, accompanied by organic pathology infarction( ischemic heart failure, hypertensive heart disease with frequent crises, acute myocardial infarction and myocardial infarction).

Clinical manifestations of blockade of the right foot of the atrioventricular bundle are non-specific and more characteristic of the main cardiac pathology, which provoked the development of the blockade. At the initial examination of the patient in favor of the blockade of bundle of His right leg indicates cleavage II tone in all auscultatory points due to asynchronous and non-simultaneous contraction of the ventricles by closing the aortic and pulmonary valves. In addition to the splitting of the second tone, its intensification during inspiration is noted, since in this period a physiological slowdown of the closing of the valves of the pulmonary valve takes place.

When determining the tactics of treatment of a patient with blockade of the right leg of the atrioventricular bundle, it should be based on the presence or absence of acute cardiac pathology. So, with blockade, which developed against a background of acute myocardial infarction, emergency hospitalization of a patient in a cardiac hospital is mandatory. If the blockade of the right leg of the bundle has developed in a perfectly healthy young man, this condition does not require medical treatment, since it rarely provokes complications and has favorable predictions for the patient's life.

In any situation, even if the existing concomitant cardiac pathology, the prognosis for the patient's life to the blockade of the right leg more favorable than the left leg of the atrioventricular bundle, as this block is almost never transforms into a complete atrioventricular block.

Blockade of the left bundle bundle branch of the

The risk group for the disease of the left bundle branch blockade is elderly women in the age group of 50-70 years old, suffering from hypertensive heart disease for a long time. At a young age in healthy people this form of rhythm disturbance practically does not occur.

Objective examination of the patients with blockade left bundle branch 90% elongation is accompanied by auscultation first tone combined with the second split-tone caused by uncoordinated contraction of the ventricles, uneven by closing of the aortic and pulmonary valves increases during exhalation.

Blockade of the electric pulse on the front left leg branching atrioventricular bundle occurs and progresses in diseases accompanied by an increase in thickness of the myocardium of the left ventricle of the projection( pathology interventricular septum, myocardial infarction, myocarditis, infectious origin, congenital and acquired defects of the aortic valve).As a result of this blockade, the impulse is not transmitted to the side wall, but spreads "from below-upward".Thus, excitation of the posterior wall of the left ventricle occurs first, and the lateral and anterior walls are excited with delay. Blockade of the left leg

atrioventricular bundle is first instigator occurrence complete atrioventricular block, ventricular tachycardia and ventricular shape flicker that in 70% of cases are fatal, so this dysrhythmia relates hazardous to the patient's life.

Incomplete bundle block bundle branch

In order to evaluate the mechanism of development of incomplete blockade of the legs of the bundle, the features of the conduction system of the heart should be taken into account. The atrioventricular fascicle has wide dimensions, therefore, conduction disturbance can be observed only in the part of the fibers related to the right or left leg of the bundle, and in this situation electrocardiography reveals signs of incomplete intraventricular blockade.

A characteristic difference between the incomplete blockade of the right bundle of the bundle and the full one is the cleavage of the QRS complex in V1-2 leads in the absence of a pronounced expansion of this ventricular complex.

The left leg of the atrioventricular fascicle has two branches, and as a result, an incomplete blockade of this leg means a violation of the advance of the electric pulse along one of the branches. In order to determine which branch of the left bundle of the bundle is blocked, it is necessary to evaluate the presence of a deviation of the electrical axis of the heart on the ECG in the II standard lead( the expressed left-hand diagram indicates blockade of the anterior branch, and the deviation of the electric axis to the right testifies to the blockade of the posterior branch).

Clinical manifestations of incomplete blockade of the bundle of the bundle are minimal, and with objective examination of the patient, auscultatory changes are not detected.

Complete blockade of the bundle branch legs

As a result of a complete blockade of the right leg of the bundle, the normal course of systolic excitation of the ventricular myocardium is disrupted. Thus, excitation from the interventricular septum is transmitted only to the cardiac muscle of the left ventricle, and excitation is transmitted to the right ventricle with a delay, since the transfer of the pulse in this case occurs via other conducting paths( Purkinje fibers).

Such anomalous excitation of the right ventricle is reflected electrocardiographically as an expansion of the ventricular complex in leads V1-2 with an unchanged value of the S-wave, which reflects the state of excitation of the left ventricle. The delay in transfer of impulse to the right ventricle is also reflected in the registration of the ECG in the form of negativity of the T wave in the right thoracic leads.

The main distinctive criterion for complete blockade of the right bundle of the bundle is the increase in the QRS aggregated ventricular complex in the II standard lead, the value of which is more than 0.12 s.

The pathogenesis of the complete blockage of the left leg of the bundle is identical, that is, the excitation from the interventricular septum is reached only by the right ventricle, from which, through the Purkinje network of fibers, the electrical impulse is transferred to the cardiac muscle of the left ventricle of the heart.

In this situation, all electrocardiographic changes are recorded in the left thoracic leads( expansion of the QRS summation complex in the second standard lead, discordant depression of the ST segment).

Block block of the bundle on the ECG

Very often, ECG diagnostics becomes the only effective method of instrumental examination, which makes it possible, even with the patient's initial treatment, to conclude that there are blockages of the bundle of the bundle. There are both common signs of ECG pattern changes, and specific for each form of blockade. Obligatory conditions for decoding the registration of electrocardiography is to estimate the width and shape of the QRS complex in all leads, as well as the definition of the thoracic leads in which the QRS complex has a cleavage.

Signs of blocking of the upper branch of the left foot of the atrioventricular bundle are:

- criteria for deviating the electrical axis to the left by at least 45%;

- expansion of QRS complex about 0,9-0,11 s;

- the presence of specific ventricular complexes of the type qR, rS / r in standard leads;

- in the chest leads decreases amplitude R and increases the depth S.

For blockade of the posterior lower branch of the left leg of the bundle, the following ECG signs of impulse conduction are characteristic:

- increased amplitude of the R wave in the III lead as compared to the II lead, which indicates a sharpDeviation of the electric axis of the heart by more than 90%;

- minor expansion of the QRS complex( not more than 0.11 s);

- width of tooth Q in III and aVF leads less than 0.04 s;

- presence of a deep tooth S in I and aVL leads with the formation of a rS wave.

Complete blockage of the left bundle branch is characterized by more significant changes in the ECG registration:

- a sharp expansion of the QRS complex more than 0.12 s;

- complete absence of S and Q teeth in I, aVL and V6 leads with simultaneous expansion of the R tooth with serrated tip;

- formation of rS and QS complex in III, aVF and V2 leads;

- definition of a descending incidence of the T wave and segment ST and dominant R wave in I, aVL and V6 leads with a discordant steep rise of the ST segment in leads V1-2.

The only difference between an incomplete blockade and a complete blockade is a slight change in the ST segment and a slight expansion of the QRS complex.

Diagnostic electrocardiographic criteria for complete blockage of the right bundle right leg are:

- extended to 0.12 with the QRS complex;

- registration in leads V1-2, aVF and III of ventricular complex of rSR type;

is an extension of the S wave and its prevalence over the width of the R wave in aVL, I and V6 leads;

- depression of the ST segment in V1-2 leads with simultaneous negation of the T wave;

Two-beam blockades have their own characteristic electrocardiographic changes, caused by impaired conductivity of the pulse along each of the bundles of the Gys. When two-beam

blockade of the anterior branch of the left leg and the right leg atrioventricular bundle observed following electrocardiographic signs:

- sharp left hand axis deviation;

- an extension of more than 0.12 from the QRS complex;

- skewed depression of the ST segment in V1-2 leads with simultaneous negation of the T wave with the formation of a ventricular complex of the rSR type;

- an increase in the depth of the S wave in leads II, III and aVF with the formation of the rS complex.

Localization of the blockade in the posterior branching of the left leg and right leg is also accompanied by a combination of characteristic ECG logging changes:

- sharp right-sided deviation of the electric axis;

- an extension of more than 0.12 from the QRS complex;

- depression of the ST segment in V1-2 leads with simultaneous negation of the T wave;

- the depth of the tooth S is greater than the depth of the tooth R in aVL and I leads.

When interpreting ECG should carefully evaluate the identified changes and compare them with the available patient clinical symptoms, as in some cases, double-bundle branch block blockade feet beam can simulate ECG signs of acute myocardial infarction transmurralnogo. Treatment

His-

beam legs blockade Due to the fact that in most cases, blockage legs atrioventricular bundle branch block is a random finding during registration electrocardiography and is not accompanied by gross organic lesions of the heart muscle specific medical and surgical treatment of this disease is not present.

People who have signs of the blockade of one of the bundle branch block, especially occurring in intermittent form, it is recommended to carry out simple rules during an attack, thus contributing to the elimination of partial intraventricular blockade attack:

- is necessary to completely eliminate physical activity during an attack, and if possible toA few minutes to take a horizontal position;

- it is recommended to perform simple breathing exercises with alternating deep inspiration and exhalation, as well as a delay in breathing during the "expiration" phase. This exercise allows a few minutes to remove the signs of blockade.

As preventive measures to reduce the number of seizures of the blockade and the prevention of its transformation into a more life-threatening atrioventricular block is recommended to observe a certain number of rules on the treatment and diet:

- mandatory daily night's sleep of at least eight hours;

- correction of eating behavior with the exception of products containing cholesterol and daily consumption of foods high in fiber;

- annual visit to a cardiologist and the passage of a control electrocardiographic and ultrasound examination.

Etiopatogenetichesky therapy is used only when clearly identified the background organic pathology of the cardiovascular system, which not only acts as an agent provocateur blockade transmission bundle of His pulse, but also to a large extent affect the prognosis and outcome of the disease.

Pathologies such as acute coronary syndrome, transmural myocardial infarction, pulmonary embolism and hypertensive crisis with concomitant signs of blockade of the bundle of the bundle are a rationale for inpatient hospitalization for qualitative diagnosis and the appointment of an adequate treatment regimen.

In a situation where the bundle of the bundle of the bundle arises against the background of high blood pressure, the use of antihypertensive agents of combined action is recommended to reduce the load on the myocardium( Kaptopres at a dose of 25 mg once and the subsequent transition to a maintenance dosage of 12.5 mg in the morning daily).

As a prophylaxis for further organic damage to the myocardium, as well as to improve the function of cardiac muscle conduction in patients with blockage of the atrioventricular bundle, the use of a course of drugs that improve metabolic processes in the myocardium( Mildronate in a daily dose of 0.5 g, Riboxin 200Mg 3 times a day, Trimetazidine in a daily dose of 40 g), a duration of at least 1.5 months.

The purpose of drug treatment is possible only with the exclusion of the blockade of the bundle of the bundle on the background of medication( the so-called "drug form" of the blockade).

No less effective in this situation are traditional medicine products, which have a cardioprotective and soothing effect( alcohol tincture of hawthorn fruit and May lily of the valley flowers in 10 drops in the morning).

Surgical method of treatment of bundle branch blockade is applied only in case of malignant progressive course with frequent Morgane-Adams-Stokes attacks and risk of full atrioventricular blockade and implantation of pacemaker as an artificial heart rhythm generator.