Anatomy and Function of the Conducting System of the Heart

Arterial Blood Supply to the Conducting System

The conducting system of the heart is responsible for generating and transmitting electrical impulses that regulate cardiac rhythm. This system includes the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, and Purkinje fibers.

Blood Supply to the SA Node

The SA node, often referred to as the heart's natural pacemaker, is primarily supplied by the sinoatrial nodal artery. This artery originates from the right coronary artery (RCA) in approximately 60% of individuals, while in others, it arises from the left circumflex artery (LCx).

Blood Supply to the AV Node

The AV node receives its arterial blood supply from the atrioventricular nodal artery, which typically branches from the posterior descending artery (PDA). The PDA itself is derived from the RCA in right-dominant circulation and from the LCx in left-dominant circulation.

Blood Supply to the Bundle of His and Purkinje Fibers

The bundle of His and its branches are supplied by septal perforating branches of the left anterior descending artery (LAD). The Purkinje fibers, which extend into the ventricular myocardium, receive blood from smaller branches of the LAD and RCA.

Clinical Significance

Compromised arterial blood supply to the conducting system can lead to arrhythmias, including sinus node dysfunction and AV block. Understanding the vascular anatomy is crucial for managing ischemic heart disease and planning interventions such as pacemaker implantation.