The sinoatrial (SA) node is the natural pacemaker of the heart. It generates electrical impulses that cause the heart’s chambers to contract, setting the heart rate. The SA node typically generates 60 ...

What Is a Normal Sinus Rhythm? Normal sinus rhythm is when your heart beats in a regular, organized way. Your body has a built-in pacemaker called the sinoatrial (SA) node, or sinus node. It uses ...

New research helps explain how the body's "flight-or-fight" response is mediated. The study may provide new answers to the question of how the heart pacemaker -- the sinoatrial node -- is regulated.

DEAR DR. ROACH: At age 76, I was diagnosed with sinus node dysfunction last year after several episodes of what I’d call being “spaced out” (for lack of a better term). I couldn’t explain these ...