What causes a bundle branch blockage?

A bundle branch blockage occurs when there is an interruption or delay in the electrical signals that control the heartbeat as they pass through the bundle branches, which are part of the heart's conduction system. The left bundle branch is one of the two main branches that carry electrical impulses from the atrioventricular (AV) node to the ventricles. When this branch is blocked, it can lead to a condition known as left bundle branch block (LBBB). The causes of a left bundle branch blockage can be varied and are often related to underlying heart conditions. Some of the most common causes include: 1. Dilated Cardiomyopathy: A condition where the heart muscle becomes weakened and enlarged, affecting its ability to pump blood effectively. 2. Hypertrophic Cardiomyopathy: A disease where the heart muscle becomes abnormally thick, which can obstruct blood flow. 3. High Blood Pressure: Over time, high blood pressure can damage the heart and lead to changes in the conduction system. 4. Aortic Valve Disease: Issues with the aortic valve can affect the heart's structure and function, potentially leading to conduction problems. 5. Coronary Artery Disease: This disease can reduce blood flow to the heart muscle, which may result in changes to the heart's electrical system. While a left bundle branch block can also be seen in individuals without heart disease, it is less common. It's important to note that the presence of a bundle branch blockage should prompt a thorough medical evaluation to determine the underlying cause and appropriate treatment.

A left bundle branch block usually is a sign of an underlying heart disease, including dilated cardiomyopathy, hypertrophic cardiomyopathy, high blood pressure, aortic valve disease, coronary artery disease and other heart conditions. While left bundle branch block can appear in healthy people, it most often does not.