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 ...

If the SA node of the heart isn't functioning properly, then this might lead to abnormal rhythms and irregular heartbeat. It is then that you might need a pacemaker. Sometimes the SA node is not able ...

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 ...

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 ...

A premature atrial contraction (PAC) occurs when a focus in the atrium (not the SA node), generates an action potential before the next scheduled SA node action potential. When this occurs prior to ...

A junctional escape rhythm is when the heartbeat starts in a different part of the heart than it should. This type of arrhythmia may not need treatment, but a doctor does need to investigate the ...