5. Signals from the right and left bundle branches travel to the ventricles and deliver the message to contract and pump the blood to the rest of the body.
6. Ventricles relax and the process begins again.
A bundle branch block occurs when this electrical signal is interrupted. The interruption can be partial or complete and may occur in either the left or right bundle branch. Because the signal is interrupted, the heart is not working at optimal efficiency.
Hearts with bundle branch blocks have to work harder than normal to deliver blood to the rest of the body. People with bundle branch block frequently have no symptoms, although some people may experience fainting, bradycardia (slower heart rate than normal), or presyncope (feeling as if you’re going to faint).
Bundle branch blocks are a very common condition. Because they are generally caused by an underlying heart condition, there is no treatment for bundle branch blocks. Instead, the underlying cause is treated. The only way to diagnose a bundle branch block is through the use of an electrocardiogram.
Bundle branch blocks can be caused by a variety of conditions:
Right Bundle Branch Block
While it may occur in healthy persons with no underlying cause, right bundle branch block may occur with any condition that affects the right side of the heart or lungs such as chronic lung diseases, blood clots in the lungs, congenital heart defects, heart attack, high blood pressure, scar tissue in the heart from prior surgery, infection of the heart muscle or cardiomyopathy.
Left Bundle Branch Block
Left Bundle Branch Block generally serves as a signal that there is an underlying heart condition such as hypertrophic cardiomyopathy, cardiomyopathy, coronary artery disease or heart disease high blood pressure, congestive heart failure or aortic valve disease.
Bundle branch block can have some serious complications. Persons with bundle branch block may experience a heart rate that is slower than normal or a heart arrhythmia or irregular heartbeat. In some cases, bundle branch block may result in cardiac arrest or sudden cardiac death.