The bundle branches are part of the normal electrical system of the heart. The electrical impulse that causes the heart muscle to contract starts high in the right atrium in a node of tissue called the sinoatrial node. From there, the electrical impulse travels through the atria, through the atrioventricular node and then down the Bundle of His, the first part of the electrical system in the ventricles. The Bundle of His then splits into two “bundles”, the left and right bundles, each directing the impulse to the respective direction. The electrical impulse then spreads out through the heart muscle through the Purkinje fibers. When any part of the heart muscle receives an impulse, it contracts.
Either the right or left bundle can fail to conduct the impulse properly. This is called a “bundle branch block”. The right or left bundle branch block each has a characteristic appearance on the EKG. Having a bundle branch block does not usually prevent the heart from contracting.
|
