Sinus rhythm is the term for the regular pattern of heartbeats driven by the heart’s natural pacemaker, the sinus node. Variations like sinus tachycardia (fast heart rate) and sinus bradycardia (slow ...

The rhythm is either sinus rhythm or not sinus rhythm. Sinus rhythm refers to the origination of the electrical activity coming from the sinus node — also known as the sinoatrial node, or SA node.

A sinus arrhythmia refers to a problem with the sinus node of the heart. This controls the rhythm of the heart and can be fast (sinus tachycardia) or slow (sinus bradycardia). This article looks at ...