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 ...

Sinus arrhythmia is when your heart beats too slowly or too fast. The change of pace may happen when you breathe. This condition is common and usually benign. But, it could indicate an underlying ...