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The normal pacemaker of the cardiac conduction system is the sinoatrial (SA) node. This specialized group of cells, located in the right atrium, generates electrical impulses that initiate each heartbeat. The SA node has the highest rate of automaticity compared to other components of the cardiac conduction system, meaning it is capable of setting and controlling the pace of the heart by automatically generating electrical signals.

These impulses spread throughout the atria, causing them to contract and push blood into the ventricles. The SA node's intrinsic firing rate typically ranges from 60 to 100 beats per minute in a resting state, which is why it is referred to as the primary pacemaker.

The other components of the conduction system, such as the atrioventricular (AV) node, the Bundle of His, and the Purkinje fibers, have slower intrinsic rates and serve as secondary pacemakers. If the SA node fails, the AV node can take over but at a reduced rate of about 40 to 60 beats per minute. The Bundle of His and Purkinje fibers can further take over if necessary, but they operate at even slower rates of 20 to 40 beats per minute. Thus, the SA node's role as the