Your heart isn’t plugged into an outlet. And you don’t use a switch to turn it on. But just like a lamp, your heart runs on an electrical system. Every time your heart beats, an electrical signal ...

Also known as complete heart block, third-degree heart block is the most serious type of heart block. Considered a medical emergency, it can be fatal without prompt treatment. The steady beating of ...

There are three types of second degree heart block, also called atrioventricular (AV) block. In type I the signal sometimes does not reach the ventricles, causing skipped beats. It is often benign and ...

This ECG shows P waves that are not always associated with a QRS complex. This is called "AV dissociation" and occurs in complete heart block (a.k.a. 3rd degree heart block). In this situation, the P ...