Blockade of the left bundle branch block

Blockade of bundle branch foot
ICD-10I 44.4 44.4 -I 44.7 44.7, I 45 45.
ICD-9426.3 426.3 - 426.5 426.5
DiseasesDB7352
eMedicineped / 2501 ped / 2500 ped / 2500
MeshD002037

Guis bundle legs are an element of the cardiac conduction system. They are responsible for conducting electrical stimulation in the ventricles of the heart. The bundle of His is divided into the rear leg of the bundle of His and two front: left front and right front. The back branch goes down, it is thicker than the others and is like a continuation of the common trunk, then the right anterior branch is separated from the general trunk first and then the left anterior branch (responsible for the left anterior ventricular septum and the anterior-lateral wall of the left ventricle). The posterior branch is responsible for the posterior-left section of the interventricular septum and the posterior (lower) wall of the left ventricle. Between the anterior and posterior branches of the left leg of the bundle of his, there is a network of anastomoses.

Based on the structure of the branches of the bundle of His, one-beam, two-beam and three-beam blockades are distinguished. With any type of single-blockade blockade, the QRS complex is slightly expanded, its width remains within the upper limit of the norm or slightly increases (0.08 - 0.11 sec.) With a complete blockade of the right leg of His, however, it can be expanded to 0.12 sec. . and more.

Pathogenesis

Diseases leading to overload and hypertrophy of the pancreas, in particular: pulmonary heart, mitral stenosis, congenital heart defects with an increase in the load on the right ventricle, coronary artery disease in combination with arterial hypertension, acute myocardial infarction, often zadnediafragmalny and apical, Brugad Syndrome. Rarely can occur in individuals without heart disease. Detection of a previously non-existent blockade of the right bundle of His can be a sign of a progressive pathological process in the heart (sarcoidosis, etc.)

Intoxication with digitalis, quinidine, overdose of b-blockers. Electrolyte disturbances. Often this type of blockade occurs in healthy young people - a variant of the norm.

Pathogenesis

Causes and risk factors

Causes that can cause a disturbance in the conduction of excitation along the structures of the His bundle are divided into cardiac and extracardiac.

Cardiac causes of blockades:

  • congenital and acquired heart defects (stenosis of the aortic orifice, pulmonary artery, left atrioventricular orifice, coarctation, or segmental narrowing, aortic orifice, aortic insufficiency, mitral valve, pulmonary artery valve, interatrial septal defects),
  • cardiomyopathy (including hypertrophic obstructive cardiomyopathy),
  • coronary artery disease,
  • dystrophic changes in the myocardium,
  • idiopathic calcification of the cardiac conduction system,
  • Brugada syndrome,
  • fibrous changes of the bundle branch foot,
  • ischemic heart disease (including myocardial infarction),
  • cardiosclerosis (including post-infarction),
  • levy's disease
  • heart failure,
  • myocarditis,
  • endocarditis,
  • left ventricular myocardial hypertrophy.

Every fifth patient with a diagnosis of “myocardial infarction” blockade of the bundle of the His bundle already exists or develops on the background of an acute condition.

  • intoxication with drugs of the cardiac glycosides group, quinidine, beta-blockers,
  • thyrotoxicosis,
  • electrolyte imbalance,
  • severe or long-standing diabetes,
  • Iron-deficiency anemia,
  • metabolic syndrome,
  • alimentary obesity,
  • chronic alcoholic illness
  • autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus, autoimmune thyroiditis),
  • pulmonary embolism,
  • chronic obstructive pulmonary diseases (obstructive bronchitis, bronchial asthma),
  • long smoking history.

Forms of the disease

In accordance with the anatomical structure of the atrioventricular bundle, the following types of blockades are distinguished:

  • one-tuft - one of the structures suffers (the right leg of the bundle of His, the front or rear branch of the left leg),
  • dvuhpuchkovaya - a combined lesion of the right leg and one of the branches of the left or violation of the conduction of nerve impulses along both branches of the left leg,
  • three-beam - simultaneous damage to the right and left legs of the bundle of His.

When blocking the left leg of the bundle of His and the full three-beam blockade, the prognosis is unfavorable. Mortality in this case increases by 5 times, the survival rate is on average 3.3 years.

The blockade of the right leg of the His bundle is asymptomatic and is an accidental finding detected by the results of an ECG study during routine medical examination, medical examination or treatment for other diseases.

Odnopuchkovye (front or rear) left blockade also does not have clinically significant manifestations.

The blockade of the left bundle of His has symptoms of the disease that caused it, most often it is:

  • decrease in tolerance to loading,
  • shortness of breath with little physical exertion,
  • heart failure,
  • heart palpitations
  • pain in the heart,
  • change of heart tones during auscultation weakened or elongated tone I (in 70% of cases), less often (16% of cases) - its splitting, splitting of the II tone (80%).

Three-bundle blockade has the most severe clinical manifestations:

  • extremely low frequency of contractions of the heart - 20–40 beats / min,
  • severe dyspnea at rest,
  • heart failure,
  • heart rhythm disorders
  • dizziness,
  • short episodes of unconsciousness,
  • cyanosis of the skin.

Diagnostics

The main diagnostic measures:

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

Blockade of the bundle of the His branch occurs in more than 0.5% of the population, the frequency increases with age: in those over 60, it is 1-2%.

Laboratory research methods do not allow to diagnose the blockade of the bundle of the His bundle and can be used to identify the underlying disease that led to conduction disturbance.

There is no specific treatment for this pathology, first of all, correction of the underlying disease with nitrates, cardiac glycosides, and hypotensive drugs is carried out.

When blocking the right leg of the bundle of His in the absence of the underlying disease, pharmacotherapy is not indicated.

When blocking the left leg or trekhpuchkovoy blockade assigned the following therapy:

  • vitamin preparations of group B,
  • antioxidants and antihypoxants,
  • antiplatelet drugs
  • lipid-lowering drugs.

With the ineffectiveness of pharmacotherapy, surgical treatment is indicated.

Possible complications and consequences

Complications of the blockade of the bundle branch block can be:

  • heart rhythm disorders
  • heart failure,
  • thromboembolism
  • acute heart failure.

The prognosis depends on the severity of the underlying disease. With a single blockade or blockade of the right leg, the prognosis is favorable.

When blocking the right leg of the bundle of His in the absence of the underlying disease, pharmacotherapy is not indicated.

The blockade of the left leg of the bundle of His and the full three-bundle blockade are less favorable prognostic. Mortality in this case increases by 5 times, the survival rate is on average 3.3 years, with a normal heart size, it is extended to 4.3 years, with an increase in the size of the heart, the average survival rate is shortened to 2.5 years.

Prognosis worsen heart failure, cardiomegaly, angina, myocardial infarction in history, atrial fibrillation, the deviation of the electrical axis to the left.

Registered in acute myocardial infarction, regardless of whether it was before the infarction or developed in connection with it, the blockade of the left bundle of His, increases the mortality of patients up to 60%.

Education: higher, 2004 (GOU VPO “Kursk State Medical University”), specialty “General Medicine”, qualification “Doctor”. 2008-2012 - Post-graduate student of the Department of Clinical Pharmacology of the SBEI HPE "KSMU", Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".

The information is generalized and is provided for informational purposes only. At the first signs of illness, consult a doctor. Self-treatment is dangerous to health!

Causes of Guis bundle blockade

Diseases of conductivity inside the ventricles can be caused by such diseases as:

- congenital and acquired heart defects - stenosis of the aortic and mitral valves, stenosis of the pulmonary artery, stenosis and coarctation of the aortic mouth, aortic valve insufficiency, atrial septal defect
- cardiomyopathy, myocardiodystrophy of various origin - endocrine (thyrotoxicosis, diabetes mellitus), metabolic (anemia), food (alcoholism, obesity), autoimmune (systemic lupus erythematosus, rheumatoid arthritis)
- coronary heart disease
- cardiosclerosis as the outcome of many cardiological diseases, leads to the replacement of part of the muscle fibers with scar tissue, including atypical muscle fibers
- myocarditis of viral or bacterial origin
- heart damage in case of rheumatism - endocarditis, myocarditis
- myocardial infarction
- long-existing arterial hypertension, leading to myocardial hypertrophy
- intoxication with cardiac glycosides
- pulmonary embolism
- chronic lung diseases (chronic obstructive bronchitis, pulmonary emphysema, severe bronchial asthma) leading to the formation of a pulmonary heart - stagnation of blood in the right atrium and ventricle with their hypertrophy and expansion

In young children and adolescents, incomplete single-arm right blockade may be accompanied by minor anomalies of heart development (additional chord in the left ventricle, open oval window, mitral valve prolapse), and in the absence of organic lesion of the heart is considered a variant of the norm.

Single or double-left blockade is almost always associated with acquired rather than congenital heart disease and cannot be regarded as a variant of the norm.

Symptoms of blockade of the bundle branch block

The right-handed blockade, as a rule, does not manifest itself and is detected by chance during the passage of a planned ECG. The presence of complaints such as shortness of breath, pain in the heart, feelings of disruption of the heart, fatigue, may be due to the underlying disease that caused the blockade.

With anterior or posterior left hemiblocade (one of the branches), clinical manifestations are also minimal and are caused by the underlying disease.

Complete left block may be manifested by palpitations, dizziness, pain in the region of the heart. It can be caused by massive changes in the heart muscle of the left ventricle, for example, acute myocardial infarction.

The three-beam blockade is caused by a complete or incomplete block in the path of a pulse. Incomplete blockade is characterized by the delay of impulses arriving to the ventricles and carried out along several intact fibers, and complete - by the absence of conduction of impulses to the ventricles and the appearance of an ectopic (not located where necessary) focus of excitation in them, and complete separation of the atria and ventricles occurs, which reduced in their rhythm with a frequency of 20 - 40 beats per minute. Such a frequency of contractions is significantly below the norm and cannot provide adequate release of blood into the aorta. It is clinically manifested by frequent dizziness, a feeling of heart failure and a tendency to faint as a result of a sharp decrease in cerebral blood flow (attacks of Morgagni - Edems - Stokes). It can lead to the development of life-threatening complications or cause sudden cardiac death.

Treatment of blockade of the bundle branch foot

There is no specific medical treatment for this conduction disturbance. Patients with a blockade of the right bundle of His in the absence of the underlying disease, do not need treatment. The following groups of drugs may be prescribed to patients with a single or two-beam blockade for the treatment of the underlying disease:

- vitamins - thiamine (vitamin B1) with lipoic acid, riboflavin (vitamin B2), nicotinic acid (vitamin PP)
- antioxidants - ubiquinone, carnitine, mexidol, preductal
- sedatives of plant origin (St. John's wort, motherwort, valerian, sage)
- antihypertensive drugs for the treatment of arterial hypertension - ACE inhibitors (perindopril, lisinopril), angiotensinogen II receptor antagonists (losartan, valsartan), beta-adrenergic blockers (bisoprolol, atenolol), calcium channel antagonists (amlodipine, verapathol), verapamine antagonists (bisoprolol, atenolol), calcium channel antagonists (amlodipine, verapathol). The last two groups should be administered with caution, as they reduce the heart rate.
- Anaginal preparations for the treatment of coronary heart disease - short and long-acting nitrates (nitroglycerin, isoket, cardict, monochinkwe)
- antiplatelet agents for the prevention of thrombosis in the heart and in vessels - aspirin, cardiomagnyl, thrombotic Ass
- lipid-lowering drugs to normalize cholesterol levels - statins (rosuvastatin, atorvastatin, simvastatin)
- diuretics and cardiac glycosides in the development of chronic heart failure - indapamide, diuver, lasix, strophanthin, digoxin
- drugs for the treatment of diseases of the bronchopulmonary system that caused the development of a "pulmonary" heart - inhaled adreno-mimetics and glucocorticosteroids (berotek, berodual, spirit, backlasone)
- antibiotics, nonsteroidal anti-inflammatory drugs for inflammation of the lining of the heart - penicillin, nimesulide, diclofenac

In addition to the medication, a surgical method is used to treat the blockade, which consists in installing a pacemaker (EX) to the patient. Complete right blockade, especially in combination with the left hemiblocade (blockade of one branch of the left leg), and complete left blockage that developed in the acute period of myocardial infarction (10-14 days), are indications for conducting temporary pacing by inserting an electrode through the central vein into the right ventricle. A three-bundle blockade with a complete atrioventricular block, a rare ventricular rhythm and Morgagni-Edems-Stokes seizures (unconsciousness) is an indication for permanent pacing (implantation of an artificial pacemaker or cardioverter-defibrillator).

Lifestyle with blockade of the bundle of His

A patient with a blockage of the right leg without clinical manifestations and without heart disease can lead a healthy lifestyle with habitual physical exertion. In the presence of the underlying disease that caused the double-or three-beam blockade, you need to limit the loads and stresses, rest more, eat right, get rid of bad habits.

When installing the patient, the patient should always carry a cardiac pacemaker card with him, avoid close exposure of electrical appliances and a mobile phone to the implantation area. For example, not leaning against the TV, talking on the phone, pressing it to your ear on the opposite side, having a hair dryer or electric shaver no closer than 10 cm from the implantation area.

The patient should visit the doctor once a year for an ECG, or more often if it is prescribed by the attending physician. When installing an EKS, the first visit to the doctor - cardiac surgeon and arrhythmologist after discharge will take place in three months, then in half a year, then twice a year.

Complications

Complications include paroxysmal ventricular tachycardias, ventricular fibrillation, asystole (cessation of cardiac activity - sudden cardiac death). Complications of the underlying disease in a patient with a blockade may be acute and chronic heart failure, thromboembolic complications (pulmonary embolism, stroke).

Prevention of the development of complications is a timely examination, regular visits to the doctor and the fulfillment of all his prescriptions, especially for patients with heart and vascular disease.

Summarizing everything written, it can be said that the blockade of the bundle of His is not a disease, but a symptom of heart disease, which is either detected on an ECG or manifests itself clinically. To know what the consequences of this or that type of blockade may be, it is necessary to take into account that the prognosis depends on the disease that led to the development of the block.

With a single block right blockade and the absence of cardiac or pulmonary pathology, the prognosis is favorable. With the development of a complete blockade of the left leg against the background of myocardial infarction, the prognosis is unfavorable, since the mortality rate reaches 40-50% in the acute period of the infarction. The prognosis of the three-bundle blockade is also unfavorable, since it increases the likelihood of asystole.

1 Anatomy

Before studying the clinic and the causes of dysfunction in the pathways, let us examine how the bundle of His. This element is a direct extension of the AV node, which is located between the upper and lower heart chambers, and is the center of automatism of the 2nd order. The AV node receives impulses from the higher center, the sinoatrial center, processes and carries the impulse further along the bundle of His.

The beam branches into two legs: right and left. In turn, the left branch is divided into front and back, which, while continuing to branch, end with Purkinje fibers. Pathology of the left leg in the form of a slowing down or absence of impulses means a blockade of the left ventricle to a greater extent, since these branches of the conducting system braid this particular cardiac section.

2 Pathology of impulses

If the violation of impulses occurs at the level of the bundle of His, intraventricular blockade occurs. If the right leg and both branches of the left are immediately affected, a three-beam blockade occurs. Multiple variations may have double-beam blockades. If only one branch of the left leg is affected, the blockade is called incomplete.

The causes of the pathology of impulses through the fibers and cells of the left leg can be the following states:

  • myocardial infarction,
  • cardiomyopathy
  • inflammatory heart diseases: myo-endocarditis,
  • cardiac pathologies that lead to an increase in the size of the left ventricle: arterial hypertension, defects, valvular defects, calcification,
  • coarctation of the aorta and its defects,
  • excess blood potassium
  • TELA,
  • intoxication with cardiac glycosides,
  • inflammation of the inner lining of the heart of bacterial origin,
  • cardiac defects.

Stress factors, excessive emotional and physical overvoltages, exogenous intoxication with alcohol and nicotine, infectious diseases, lack of sleep and rest, irregular working hours, and “wear and tear” can provoke a deterioration in conductivity. These factors are predisposing to the occurrence of the above violations - the causes of the development of blockades.

A complete blockade is a dangerous and sometimes life-threatening condition.

If conduction disturbances are minor, i.e. impulses pass, but with minimal delay, without affecting the work of the heart and hemodynamics - there is no particular cause for concern. The nature is very prudent, since for such cases it has come up with workarounds for carrying out the impulses - anastomoses, in case the individual fibers of the left leg branch suddenly fail.

A complete blockade is a dangerous and sometimes life-threatening condition, as well as blocking the impulses of large trunks of the branches of the left leg. At the same time, extensive sections of the myocardium are not reduced, bypass routes do not work. These areas are simply turned off from the cardiac rhythm, and what is even worse, the myocardial fibers begin to contract randomly, each in its own rhythm with the development of very dangerous ventricular arrhythmias that can be fatal.

5 Symptoms

It should be understood that this condition is not an independent disease, but a sign of cardiac pathology. It indicates that the patient has a health problem: organic heart disease or non-heart disease. The clinic and the symptoms of both complete and incomplete blockades are always caused by the underlying disease - the cause that provoked them. If it is a heart attack, the clinic will be bright: acute chest pains, not resolved by nitroglycerin, with atherosclerotic cardiosclerosis, the process will proceed gradually, with the development of shortness of breath, chest heaviness, interruptions in the heart.

Rule No 1: There are no specific symptoms for blocking the left bundle of the bundle of His. The clinical picture may be completely absent or be due to the underlying disease. A blockade may not manifest itself at all and may be detected as a random find at the time of removing the cardiogram, for example, during a medical preventive examination. Such asymptomatic conditions are very dangerous because they increase the risk of sudden cardiac death in patients.

When a blockade without clinical manifestations is detected, repeated studies should be conducted regularly to monitor the dynamics of the pathways. In the case of conduction disorders, the absence of symptoms does not mean the absence of heart problems.

7 Treatment of blockade of the left bundle.

Elimination of the cause of the blockade of the left leg

There is no specific treatment. Correction should be carried out on the underlying disease. If the reason lies in the coronary artery disease, ischemic changes, it is necessary to appoint according to indications of nitrates, cardiac glycosides, diuretics, cardioprotective drugs. If a patient has a transient blockade on the background of hypertensive crises, you should correctly choose the pills that help maintain blood pressure figures at a normal level. With valvular defects, the question of surgical correction may be considered.

Treatment of myocarditis is carried out by hormonal drugs, nonsteroidal anti-inflammatory drugs, if a bacterial pathogen has been identified - it is necessary to conduct a full course of antibiotic therapy with a preliminary study of the susceptibility of the microorganism to AB. If electrolyte disturbances are the cause of the blockade, they are corrected and the electrolyte level in the blood is brought to normal with subsequent biochemical control.

Elimination of the cause of the blockade of the left leg contributes to its disappearance or reduction. The exception is post-infarction changes that have occurred as a result of the extinction of some elements of the pathways. In this case, to reduce the ECG signs are unlikely to succeed. Such patients are assigned ECG monitoring over time.

General information

Blockade of the Gis bundle legs is an incomplete or complete disruption of the passage of an electrical impulse through the cell bundles of the cardiac conduction system, leading to a change in the sequence of ventricular myocardial coverage. In cardiology, blockade of the bundle of the His branch is not considered as an independent disease. As a rule, it acts as a consequence and at the same time an electrocardiographic symptom of any independent cardiac pathology. According to the ECG, blockade of the bundle of the His path is diagnosed in 0.6% of people, more often in men, among persons over 60 years old, its frequency increases to 1-2%.

The bundle of His is a part of the cardiac conduction system, represented by clusters of modified muscle fibers. In the interventricular septum the bundle of His is divided into two legs - right and left. In turn, the left leg is divided into anterior and posterior branches, which descend on both sides of the interventricular septum. The smallest branches of the intraventricular conduction system are Purkinje fibers, which penetrate the entire heart muscle and are directly connected with the contractile ventricular myocardium. Myocardial contractions occur due to the propagation of electrical impulses originating in the sinus node, through the atria to the atrioventricular node, then through the bundle of His and his legs to the Purkinje fibers.

Classification blockade of the bundle branch block

Taking into account the anatomical structure of the bundle of His, the blockade can be one-beam, two-beam, and three-beam. Single-beam blockade includes cases of lesion of only one leg (branch) of the His bundle: blockade of the right leg, blockade of the left anterior or left posterior branch. Two-bundle blockades are a simultaneous lesion of 2 branches of the bundle of His: the anterior and posterior branches of the left leg, the right leg and the anterior left branch, the right leg and the posterior left branch. With three-beam blockades, all three branches of the His bundle are affected.

According to the degree of violation of the impulse of blocking the legs of the bundle of His, they may be incomplete and complete. In case of incomplete blockade, the conduction of a pulse along one of the legs of the His bundle is disturbed, while the functioning of the second leg or one of its branches is not disturbed. In this case, the excitation of the myocardium of the ventricles is provided by intact branches, but occurs with a delay.

Thus, with the slowing down of the process of the propagation of an impulse along the branches of the bundle of His, there is an incomplete heart block I degree. In that case, if not all impulses reach the ventricles, they speak of an incomplete heart block II degree. Complete blockade (or blockage of III degree) is characterized by the absolute impossibility of conducting impulses from the atria to the ventricles, in connection with which the latter begin to contract independently, at a speed of 20-40 beats. in minutes

Blockade of the feet of the bundle of His can be transient (intermittent) or permanent (irreversible). In some cases, the blockade of the bundle of the His branch develops only when the heart rate changes (bradycardia, tachycardia).

Characteristics of the various options blockade of the bundle branch block

Blockade of the legs of the bundle of His does not have independent clinical manifestations, in most cases they are manifested by symptoms of the underlying disease and specific ECG changes. In some cases, with a decrease in cardiac output, the blockade of the bundle of the His bundle may be accompanied by frequent dizziness, severe bradycardia, and sometimes - bouts of unconsciousness.

Consider the main clinical options for blocking the bundle of His.

Blockade of the right bundle branch block

In the case of a complete blockade of the right leg of the bundle of His, the impulse and excitation of the myocardium of the right ventricle and the right half of the MILV are performed along the contractile muscle fibers from the left ventricle and from the left half of the MILV. In case of incomplete blockade, a deceleration of conducting an electrical impulse along the right leg of the His branch is noted. Sometimes incomplete blockade of the right bundle of His is detected in practically healthy young people, in this case it is regarded as a variant of the physiological norm.

ECG-signs of complete blockade of the right bundle of His bundle are expansion of the S wave, increase in amplitude and expansion of the R wave, the QRS complex has the form of qRS with an extension of up to 0.12 sec. and more.

Blockade of the left bundle branch block

With a complete blockade of the left leg of the His bundle, a wave of excitation is not conducted along the stem of the leg until it branching out or does not extend simultaneously to both branches of the left leg (two-beam blockade). The excitation wave is transmitted to the myocardium of the left ventricle with a delay from the right half of the MILV and the right ventricle along the Purkinje fibers. On the ECG - the deviation of the EOS to the left, the broadening of the QRS complex to 0.12 seconds. or more.

At the heart of the blockade of the anterior branch of the left leg of the bundle of His is a violation of the impulse to the anterolateral wall of the myocardium of the left ventricle. In this case, after the excitation of MUZhP and lower sections of the posterior wall along the anastomoses of Purkinje fibers, the excitation wave propagates from the anterolateral wall of the left ventricle from the bottom up.

During the blockade of the posterior branch of the left leg of the bundle of His, impaired conduction to the lower back parts of the myocardium of the left ventricle is disturbed. The wave of activation propagates from the anterior and anterolateral wall of the left ventricle along the Purkinje fibers to the lower back sections of the left ventricle, i.e. from top to bottom.

Incomplete blockade of the left leg of the bundle of His is characterized by a slowing down of the impulse conduction along the main left trunk or along both branches of the left leg. At the same time, part of the myocardium of the left ventricle is excited by impulses propagating along the right leg.

Two-beam blockade

When combined with the blockade of the right leg of the bundle of His, blockade of the left anterior branch, an electrical impulse propagates along the back branch of the left leg of the bundle of His, causing excitation first of the lower back sections of the myocardium of the left ventricle, then its anterolateral segments. Following this, the impulse slowly spreads to the right ventricular myocardium along the contractile fibers.

The delay in excitation of the anterolateral wall of the left ventricle and right ventricle is reflected on the ECG in the form of an expansion of the QRS complex to 0.12 seconds, the serration of the ascending knee of the S wave, negative T wave, EOS deviation to the left.

In the case of a combined blockade of the right bundle of His's bundle with a blockade of the posterior left branch, the impulse is conducted through the anterior left branch, the anterolateral departments of the left ventricle anastomosis to the lower back sections of the left ventricle, and then the contractile fibers to the right ventricle. The ECG reflects signs of blockade of the left posterior branch and right leg of the His bundle, deviation of the EOS to the right. This combination indicates common and profound changes in the myocardium.

Three-beam blockade

Incomplete three-bundle blockade is accompanied by the spread of an excitation pulse to the ventricles along the least affected branch of the bundle of His. At the same time atrioventricular block I or II is marked.

In the case of a full three-bundle blockade, the conduction of impulses from the atria to the ventricles becomes impossible (AV-blockade of the third degree), which leads to the dissociation of the atrial and ventricular rhythms. At the same time, the ventricles contract in their own idioventricular rhythm, which is characterized by low frequency and arrhythmia, which can lead to the appearance of atrial fibrillation and asystole of various duration.

The ECG pattern with complete blockade of the bundle of the His branch corresponds to the signs of AV blockade of one degree or another.

Prediction of blockade of the bundle branch block

The prognosis of the bundle of His bundle in asymptomatic patients is favorable. In the presence of organic pathology of the heart, the prognosis is determined by the underlying disease. In turn, the blockade of the bundle of his bundle increases both the risk of sudden death in this category of patients and the development of long-term complications.

The progression of the defect of the conduct, the development of AV-blockade, cardiomegaly, hypertension and heart failure increases the likelihood of an adverse outcome.

Watch the video: Intro to EKG Interpretation - Bundle Branch Blocks (January 2020).