Indications for Pacemaker Implantation in Bifascicular Block

Class I Indications

The American College of Cardiology recommends permanent pacemaker implantation for patients with bifascicular block who have intermittent complete heart block with symptomatic bradycardia, or bifascicular/trifascicular block with intermittent type II second-degree AV block, regardless of symptoms 1, 2
Bifascicular block with intermittent complete heart block associated with symptomatic bradycardia is a class I indication for pacemaker implantation, according to the American College of Cardiology 1, 4
The American Heart Association suggests that bifascicular or trifascicular block with intermittent type II second-degree AV block is a class I indication for pacemaker implantation 1
Persistent advanced second-degree AV block or complete heart block after acute myocardial infarction with block in the His-Purkinje system is a class I indication for pacemaker implantation, as recommended by the American College of Cardiology 4, 5
The American College of Cardiology recommends pacemaker implantation for patients with syncope and bifascicular block when other causes have been excluded, especially if syncope may have been due to transient third-degree AV block 1, 2

The American College of Cardiology suggests that bifascicular or trifascicular block with syncope not proven to be due to complete heart block, when other causes have been excluded, is a class IIa indication for pacemaker implantation 1
Markedly prolonged HV interval (≥100 ms) found during electrophysiological study is a class IIa indication for pacemaker implantation, according to the European Heart Journal 4, 6, 1
Intra- or infra-Hisian block demonstrated during incremental atrial pacing at a pacing rate <150 bpm during electrophysiological study is a class IIa indication for pacemaker implantation, as suggested by the European Heart Journal 6, 7
Patients with syncope and bundle branch block with normal HV conduction time may benefit from pacemaker implantation, according to the European Heart Journal 6, 7

Asymptomatic bifascicular block without evidence of intermittent AV block is not an indication for pacemaker implantation, according to the European Heart Journal and the American College of Cardiology 6, 1, 2
Acquired left anterior hemiblock in the absence of AV block is not an indication for pacemaker implantation, as stated by the American College of Cardiology 4
First-degree AV block with bundle branch block not previously demonstrated is not an indication for pacemaker implantation, according to the American College of Cardiology 4

The rate of progression from bifascicular block to complete heart block is generally slow, according to the American College of Cardiology and the American Heart Association 1, 2
No single clinical or laboratory variable, including bifascicular block alone, identifies patients at high risk of death due to future bradyarrhythmia, as stated by the American College of Cardiology and the American Heart Association 1, 2
PR interval prolongation is common in patients with bifascicular block, but the delay is often at the level of the AV node and does not correlate with progression to complete heart block or sudden death, according to the American College of Cardiology and the American Heart Association 1, 2
Although HV interval prolongation is associated with increased mortality, death is often due to underlying heart disease rather than AV block, as suggested by the American College of Cardiology and the American Heart Association 1, 2
In patients with neuromuscular disease and any degree of fascicular block, cardiac pacing may be indicated due to unpredictable progression of AV conduction disease, according to the European Heart Journal 6, 7

For patients with bifascicular block requiring pacing, suitable modes include VVI, DDD, or single-lead VDD, as recommended by the European Heart Journal 6, 7
Devices that maintain synchrony between atria and ventricles (DDD/VDD) are generally preferred, especially in older patients, to maintain the contribution of atrial contraction to ventricular filling, according to the European Heart Journal and the American College of Cardiology 8, 3