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Left bundle branch block (LBBB) is an intraventricular heart block that slows or breaks conduction in the left bundle branch. A left bundle branch block may be a symptom of many heart diseases.
What is the left bundle branch block?
Left bundle branch block does not give specific symptoms. However, it is quite a serious heart problem, as it may worsen the symptoms of a patient’s previous medical conditions – for example, heart failure.
The heart is made of muscle cells that contract as a result of the impulses reaching them. The conductive system consists of the sinoatrial and atrioventricular nodes, the atrioventricular bundle and the bundle branch, i.e. pęczka Stock and its right and left branches.
When the heart is working properly, impulses that stimulate the cardiomyocytes pass successively through the individual elements of the stimulus-conducting system. They arise in the sinoatrial node, pass through the atrioventricular node, and then through bundle branches of His are sent to the farthest nerve fibers of the heart.
When a conductive system does not function properly, so-called heart blocks appear, the names and mechanisms of which differ depending on where the heart is disturbed. There are, for example, atrioventricular block, where the transmission of impulses between the atria and the heart chambers is impaired, and so-called intraventricular blocks, one of the types of which is left bundle branch block.
If it comes to left bundle branch blockyou have a specific condition disturbance of the heart rhythmwhich allows you to diagnose this ailment.
Heart rhythm disturbance in the case left bundle branch block most often it does not cause any additional symptoms noticeable to the patient – it is detected during heart examination (ECG, heart echo). Sometimes in severe cases associated with advanced coronary heart disease left bundle branch block Symptoms of shortness of breath and chest pain may appear. Left bundle branch block impairs the work of the left ventricle and makes the symptoms of ischemic heart disease and heart failure intensify, hence these ailments.
The causes of the left bundle branch block
Left bundle branch block may be due to the following reasons:
- advanced ischemic heart disease,
- recent myocardial infarction,
- aortic stenosis, also known as stenosis,
- rozstrzeniowa cardiomyopathy,
- myocarditis.
These are the most common causes this disorder, nevertheless left bundle branch block it can also be caused by other pathologies in the transmission of impulses in the heart’s conduction system. One of the less obvious causes This disease is, for example, Lyme disease caused by a tick bite.
How is left bundle branch block diagnosed?
Left bundle branch block is diagnosed on the basis of the examination ECG (cardiac electrocardiography). Left bundle branch block is diagnosed when the following heart problems are present:
- Widening of the QRS complex above 120 milliseconds – this means that the ventricles contract for too long; the left ventricle contracts more slowly than the right ventricles and hence the cumulative contraction time of both ventricles is extended.
- A wide and interlocking (M-shaped) R wave in some ECG leads.
- QRS or RS complex in leads V1, V2 and V3 – there is no upward tilt of the ECG curve (R wave) after downward tilt (Q wave).
- Changes in the ST segment and T wave – this allows to identify changes in the repolarization of myocardial cells, i.e. changes in their return to the baseline state after contraction. In the left bundle branch block, ST and T changes in the direction opposite to the main deflection of the QRS complex.
Prognosis and treatment for left bundle branch block
Treatment of left bundle branch block it depends on the cause that led to the appearance of this ailment. The same is the case with bargain – they depend on the underlying cause left bundle branch block.
If left bundle branch block appears in a patient with previously diagnosed ischemic heart disease, usually it is necessary to introduce a more intensive one treatment improving the efficiency of the heart muscle.
If as a result left bundle branch block you experience fainting, it may be necessary to implant a pacemaker, popularly known as a pacemaker.
In the case of left bundle branch block resulting from ischemic heart disease prognosis are generally better than when left bundle branch block appears as a result of a recent infarction. In any case, this ailment disrupts the work of the heart and leads to pathologies in the conduction of impulses, thereby weakening the heart muscle and the circulatory system.