cardiovascular disorders
Atrioventricular Block
Key Points
There are 3 degrees of AV block: first, second, and third. First- and second-degree blocks are partial and third-degree block is complete. First-degree AV block is rarely symptomatic and no treatment is required. Second-degree AV block Mobitz type I may be physiologic and if heart rate slows, a reliable junctional escape rhythm typically develops and treatment is therefore unnecessary unless symptomatic bradycardia occurs. Second-degree AV block Mobitz type II and third-degree AV block are always pathologic and a pacemaker is typically required unless the cause is transient or reversible. 