Bundle branch block - partial or total disruption of the flow of electric pulse bundles of cells of the cardiac conduction system, leading to a change in the sequence of coverage ventricular myocardium. In the Cardiology bundle branch block blockade is not regarded as an independent disease. As a rule, it appears the investigation and at the same time electrocardiographic sign of any independent cardiac pathology. On ECG, bundle branch block blockade diagnosed in 0.6% of people, mostly men; among those over 60 years of rate increases to 1-2%.
Bundle of His - of the cardiac conduction system, represented by clusters of modified muscle fibers. The interventricular septum bundle of His divides into two legs - the right and left. In turn, the left leg is divided into anterior and posterior branches which descend on either side of the interventricular septum. The smallest branches of the intraventricular conduction system are the Purkinje fibers, which permeate the entire heart muscle and are directly related to myocardial contractility of the ventricles. Acronyms infarction is due to the spread of electrical impulses originated in the sinus node through the atria to the atrioventricular node, and then - on the beam of His and his legs to the Purkinje fibers.
atrial septal defect, tricuspid valve insufficiency, coronary heart disease, pulmonary heart, hypertension, acute myocardial infarction (zadnediafragmalnom or verhneverhushechnom) and others.
By the blockade left bundle branch block feet cause atherosclerotic cardio, aortic valve defects, cardiomyopathy, myocardial infarction, myocarditis, bacterial endocarditis, myocardial. Less bundle branch block develops on the background of pulmonary embolism, hyperkalemia and cardiac glycoside intoxication.
The reasons are two-stream blockages usually aortic disease (aortic regurgitation, aortic stenosis) and coarctation of the aorta.
dizziness, severe bradycardia, sometimes - seizures loss of consciousness.
Consider the main clinical variants of bundle branch block.
The blockade of right bundle branch block
In the event of a total blockade bundle branch block conduction of impulses of the right leg and the excitement of the right ventricle and the right half MZHZHP occurs contractile muscle fibers of the left ventricle and the left half MZHZHP. With incomplete blockade marked slowing of the electrical pulse by right bundle branch block. Sometimes an incomplete right bundle branch block is detected in apparently 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 branch block feet serve as the expansion wave S, increasing the amplitude and the expansion wave R, QRS-complex has qRS form with expansion up to 012 sec. and more.
The blockade of the left leg bundle branch block
With complete blockade of left bundle branch block wave excitation beam is not carried out on the trunk of her legs to a branch or not apply at the same time to both branches of the left foot (two-beam block). excitation wave is transmitted to the myocardium of the left ventricle with a delay from the right half MZHZHP and right ventricular Purkinje fibers. The ECG - rejection EOS left, widening of the QRS complex to 012 seconds. or more.
At the heart of left bundle branch block blockade of the anterior branch is a violation of the pulse to the anterolateral wall of the left ventricle. In this case, after the commencement MZHZHP and lower parts of the back wall on the Purkinje fibers anastomoses wave excitation extends to anterolateral wall of the left ventricle from the bottom up.
When the blockade rear branch of the left bundle branch conduction of impulses to the low back is broken areas of the left ventricle. Wave activation extends from the anterior and anterolateral wall of the left ventricle on the Purkinje fibers in the low back sections of the left ventricle, t. E. From top to bottom.
Incomplete blockade of the left bundle branch block is characterized by a slowing of momentum for the left main trunk or on both branches of the left leg. Part of the left ventricle is excited by pulses propagating from the right leg.
When combined blockade of the right bundle branch block with the blockade of the left anterior branch of the spread of the electric pulse is on the posterior branch of left bundle branch block, causing excitement first low back left ventricular departments, then - his anterolateral departments. Following this, the fibers under the contractile impulse spreads slowly on the myocardium of the right ventricle.
Delay excitation anterolateral wall of the left ventricle and the right ventricle is recognized on an electrocardiogram as an extension of the QRS-complex and 012 seconds, serration ascending limb the S-wave, negative T wave, EOS deviation to the left.
When combined blockade of the right bundle branch blockage from the back of the left branch of impulse conduction through the front left leg, anterolateral departments left ventricular myocardium anastomoses to the low back department of the left ventricle, and then - on the contractile fibers of the right ventricle. ECG reflects the signs of the blockade and the left posterior branch of the right bundle branch block, a deviation to the right AES. This combination indicates the widespread and profound changes in the myocardium.
Part Three-beam blockage is accompanied by the spread of the excitation pulse to the ventricles of the Least affected branch bundle branch block. It is noted atrioventricular block I or II.
In the case of a full blockade Three-beam conduction of impulses from the atria to the ventricles it becomes impossible (AV block III degree), which leads to dissociation of the atrial and ventricular rhythms. This ventricles in idioventricular own rhythm, characterized by low frequency and arrhythmia, which can lead to the appearance of atrial fibrillation and asystole different durations.
ECG pattern at full bundle branch block corresponds featured AV block one degree or another.
transesophageal electrocardiography (CHPEKG) rhythmocardiography, ambulatory ECG monitoring. To identify the data for organic heart failure is performed echocardiography, MRI, MDCT, PET heart.
In identifying the bundle branch block requires patient consultation cardiologist or cardiac surgeon arrhythmology.
Specific therapy bundle branch block does not exist; if the violation is necessary to treat the underlying disease. When bundle branch block complicated with angina, hypertension, congestive heart failure, therapy is performed by nitrates, cardiac glycosides, antihypertensives. When AV block should be considered indications for pacemaker implantation. When bundle branch block that runs without clinical manifestations, conducted follow-up.
Forecast bundle branch blocklegs.
Forecast bundle branch block blockade in asymptomatic patients is favorable. In the presence of organic pathology prognosis is determined by the underlying disease of the heart. In turn, bundle branch block blockade increases the risk of sudden death in these patients, and the development of long-term complications.
The progression of the defect, the development of AV block, cardiomegaly, hypertension and heart failure increases the likelihood of an unfavorable outcome.