Which node is recognized as the main pacemaker of the heart?

The sinoatrial (SA) node is recognized as the main pacemaker of the heart because it is responsible for initiating the electrical impulses that stimulate heartbeats. Located in the right atrium, the SA node generates regular electrical signals, which cause the atria to contract and push blood into the ventricles. This rhythmic activity sets the pace for the entire heart, influencing the heart rate and controlling the timing of the cardiac cycle.

The SA node’s role as the primary pacemaker is crucial because it ensures that the heart beats in a coordinated and efficient manner. If the SA node fails or is not functioning properly, other structures in the heart, such as the AV node or Purkinje fibers, may take over as secondary pacemakers, but they do so at a slower rate. This highlights the SA node's unique position as the natural pacemaker of the heart. The Bundle of His also plays a part in the conduction system, but its primary role is to transmit impulses from the AV node to the ventricles, rather than initiating them.