What does a sinus rhythm indicate on an EKG?

A sinus rhythm on an EKG indicates that the heartbeat originates from the sinoatrial (SA) node, which is the natural pacemaker of the heart. The SA node is located in the right atrium and initiates electrical impulses that cause the heart to contract and pump blood. In a normal sinus rhythm, these impulses are generated at a regular rate, leading to a consistent pattern of P waves followed by QRS complexes on the EKG tracing.

This regularity signifies that the heart is functioning effectively under normal physiological conditions. The presence of P waves preceding each QRS complex is a hallmark of sinus rhythm, further confirming that the signals are originating from the SA node. In contrast, rhythms that derive from other areas, such as the AV node or those exhibiting irregularity, do not represent the normal functioning and coordination provided by the SA node.