Bradycardia is a condition characterized by a slower than normal heart rate. While a normal adult heart beats between 60 and ...

Bradycardia occurs if impulses are sent from the SA node at a decreased rate or if their conduction is delayed. Usually, a decline in heart rate to below 50 or 60 bpm is termed bradycardia. Types ...

What is first-degree heart block – both in terms of what it means within the heart and how that translates into ECG findings – and how common is it? The electrical activity in the heart starts in the ...

This results in a decreased heart rate through decreased sinoatrial (SA) node activity and decreased atrioventricular (AV) nodal conduction, as well as decreased inotropy — contractility — of ...

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. There are four main ...

Normally, the SA node sets the beat of your heart. It speeds up when you exercise or feel emotional, and slows down when you sleep . Ordinarily, your SA node is in complete control of the pace of ...

D'Souza A, Wang Y, Anderson C, et al. A circadian clock in the sinus node mediates day-night rhythms in Hcn4 and heart rate. Heart Rhythm. 2021;18(5):801-810. Boas EP, Weiss MM. The heart rate during ...

INJURY to the invisible subendocardial conduction system during surgical closure of congenital defects in the ventricular septum is an uncommon but extremely grave complication.1 , 2 Impalement of ...