Heart blocks are caused by a blockage in the conduction system at which specific point?

Heart blocks refer to an impairment in the conduction of electrical impulses through the heart's conduction pathways. The most common site for this blockage is the atrioventricular (AV) node. The AV node acts as a gatekeeper, allowing electrical impulses to travel from the atria to the ventricles. When there is a blockage or delay at this point, it leads to different types of heart blocks, such as first-degree, second-degree, or third-degree blocks.

A first-degree heart block, for example, is characterized by a prolonged PR interval, while second-degree heart blocks may show dropped beats on an ECG. Identifying the AV node as the point of blockage is essential for understanding the implications for heart rhythm and function.

In contrast, while issues in the sinus node, Purkinje fibers, or bundle branches can lead to other conduction disturbances, they do not specifically define the classic presentation of heart blocks as seen with AV node blockages. Therefore, focusing on the functions and locations within the conduction system emphasizes why the AV node is the primary site associated with heart blocks.