What defines a normal sinus rhythm?

A normal sinus rhythm is characterized by a heart rate that falls within the range of 60 to 100 beats per minute, accompanied by a regular rhythm. This means that each heartbeat originates from the sinoatrial (SA) node, and the intervals between each beat are consistent. This regularity indicates that the electrical impulses are being conducted properly through the heart's conduction system.

In normal sinus rhythm, not only is the heart rate appropriately set within that optimal range, but the regularity of the rhythm is also essential; any deviations, such as irregularities or alterations in the heart rate, would suggest conditions such as arrhythmias or other cardiac issues. Therefore, the definition of normal sinus rhythm encapsulates both the appropriate rate and the regularity of beats, making the choice that identifies this range with regular rhythm the correct and complete definition.