What parts of the heart's electrical conduction system are involved in ventricular contraction?

Ventricular contraction is primarily governed by the electrical conduction system of the heart, particularly through the role of the bundle branches. The bundle branches are part of the conduction pathway that follows the atrioventricular (AV) node. After the electrical impulse travels from the sinoatrial (SA) node to the AV node, it proceeds through the bundle of His and then splits into the right and left bundle branches. These branches extend through the ventricles, transmitting electrical impulses that stimulate the ventricular myocardial cells to contract in a synchronized manner.

The effective contraction of the ventricles is critical for pumping blood efficiently to the lungs and the rest of the body. Dysfunction in the bundle branches can lead to impaired or uncoordinated contractions, resulting in decreased cardiac output and potential clinical issues.

While the ventricles do contract as a result of the electrical impulses, they are not part of the conduction system itself; instead, they are the muscle tissue that responds to these impulses. The AV node and coronary arteries do play roles in cardiac function, with the AV node facilitating the conduction delay necessary for atrial contraction and the coronary arteries supplying blood to the heart muscle, but they do not directly initiate or conduct the impulses responsible for ventricular contraction. Therefore, the bundle branches