First Degree AV Bock

First-degree atrioventricular block (AV block), or PR prolongation, is a disease of the electrical conduction system of the heart in which the PR interval is lengthened beyond 0.20 seconds.

In first-degree AV block, the impulse conducting from atria to ventricles through the atrioventricular node (AV node) is delayed and travels slower than normal.

Heart Blocks

First Degree AV Block

Second Degree AV Block - Type 1 (wenckebach)

Second Degree AV Block - Mobitz Type 2

3rd Degree AV Block (Complete Heart Block)