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 ...

The sinus of your heart has nothing to do with your nose as you might guess; it’s a structure in the right atrium where blood ...

Sinoatrial exit block occurs when the action potential initiated by the sinoatrial node is inhibited or completely blocked before it is able to leave the SA node and reach the atrium, and thus no P ...

Junctional rhythm is an irregular heart rhythm that stems from a natural pacemaker in the heart known as the atrioventricular junction. The heart has several built-in pacemakers that help control its ...

What is Sick Sinus Syndrome (SSS)? Sick sinus syndrome is not a disease condition but a clinical syndrome that is related to the sinoatrial node (SA node). It is also referred to as sinus node disease ...

A premature atrial contraction occurs when a focus in the atrium (not the sinoatrial node) generates an action potential before the next scheduled SA node action potential. There are four main ...