Recommendations for Permanent Pacing in Chronic Bifascicular Block

Class I

(1) Permanent pacemaker implantation is indicated for advanced second-degree AV block or intermittent third-degree AV block.

(2) Permanent pacemaker implantation is indicated for type II second-degree AV block.

(3) Permanent pacemaker implantation is indicated for alternating bundle-branch block.

Class IIa 

(1) Permanent pacemaker implantation is reasonable for syncope not demonstrated to be due to AV block when other likely causes have been excluded, specifically ventricular tachycardia (VT).

(2) Permanent pacemaker implantation is reasonable for an incidental finding at electrophysiological study of a markedly prolonged HV interval (greater than or equal to 100 milliseconds) in asymptomatic patients.

(3) Permanent pacemaker implantation is reasonable for an incidental finding at electrophysiological study of pacing-induced infra-His block that is not physiological.

Class IIb 

(1) Permanent pacemaker implantation may be considered in the  setting of neuromuscular diseases such as myotonic muscular dystrophy, Erb dystrophy (limb-girdle muscular dystrophy), and peroneal muscular atrophy with bifascicular block or any fascicular block, with or without symptoms.

Class III  

(1) Permanent pacemaker implantation is not indicated for fascicular block without AV block or symptoms.

(2) Permanent pacemaker implantation is not indicated for fascicular block with first-degree AV block without symptoms.

JACC. 2008; 51; 2085-2105.