What is the primary role of the AV node in Junctional Rhythm?

The primary role of the AV (atrioventricular) node in junctional rhythm is to pace the heart when the SA (sinoatrial) node fails. In situations where the SA node, which is the natural pacemaker of the heart, is not functioning properly or there is a block, the AV node can take over the pacing role. This is particularly significant in junctional rhythms, where the heart rhythm originates from the AV node itself rather than the SA node.

The AV node has the capability to generate impulses at a slower rate than the SA node, typically around 40 to 60 beats per minute, thereby ensuring that the heart continues to beat and maintain some level of cardiac output when the primary pacemaker is compromised. This alternative pacing mechanism highlights the importance of the AV node in maintaining cardiac function under that specific circumstance.

While the AV node does conduct impulses to the ventricles, its primary role in junctional rhythm is more about maintaining the rhythm through pacing, particularly when the SA node is inactive. The AV node is not responsible for initiating the heartbeat per se, as that role is mainly attributed to the SA node. Additionally, the regulation of heart rate during exercise primarily involves sympathetic nervous system modulation and is not directly tied