Third-degree atrioventricular nodal block, also known as third-degree heart block or complete heart block, occurs when no action potentials conduct through the AV node. This results in the P waves ...

Note the irregular R-R intervals making 3rd degree heart block unlikely. The rhythm on this ECG needs to be distinguished from high grade AV block which is a form of 3rd degree AV block that can ...

The first is the least serious and you may not have symptoms. A second degree heart block sometimes causes troublesome symptoms that need treatment and a third degree heart block is the most serious.