From the Guidelines
No, a pacemaker is generally not needed for asymptomatic bifascicular block. Asymptomatic bifascicular block, which involves blockage in two of the three fascicles of the heart's conduction system, does not require pacemaker implantation in the absence of symptoms, as stated in the guidelines by the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society 1.
The risk of progression to complete heart block is relatively low, and the potential risks and complications of pacemaker implantation outweigh the benefits in truly asymptomatic individuals with stable conduction disease. Instead, these patients should undergo regular cardiac monitoring with annual electrocardiograms and clinical evaluations to detect any progression of conduction disease.
Some key points to consider in the management of asymptomatic bifascicular block include:
- The presence of additional conduction abnormalities
- Underlying structural heart disease
- Electrophysiological evidence of significant His-Purkinje conduction delay
- Development of symptoms such as syncope, presyncope, or documented episodes of high-grade atrioventricular block, which would indicate the need for pacemaker implantation 1.
Overall, the approach to asymptomatic bifascicular block prioritizes careful monitoring and evaluation over immediate pacemaker implantation, unless symptoms or other indications for pacing develop.
From the Research
Asymptomatic Bifascicular Block and Pacemaker Need
- The need for a pacemaker in patients with asymptomatic bifascicular block is a topic of discussion among medical professionals 2, 3, 4, 5.
- Studies have shown that the risk of complete heart block in patients with bifascicular block is low, and prophylactic pacing may not be necessary 3, 4.
- A study published in 1999 found that transcutaneous pacing was safe and effective in patients with asymptomatic chronic bifascicular block or left bundle branch block, but did not recommend routine prophylactic placement of a pacemaker 2.
- Another study published in 1981 found that no patient with bifascicular block and a long PR interval developed complete heart block during anesthesia, and concluded that prophylactic pacing is not necessary in asymptomatic patients 3.
- A 1998 study found that the incidence of perioperative bradyarrhythmias in patients with bifascicular block or left bundle branch block was low, and that an additional first-degree atrioventricular block did not increase the risk of severe bradyarrhythmias 4.
- A 2010 review article discussed the indications for temporary cardiac pacing in patients with bifascicular block undergoing anesthesia, and highlighted the importance of being aware of the current recommendations for permanent pacing in patients with chronic bifascicular and trifascicular block 5.
- A 2012 study sought to identify the optimal management strategy for patients with syncope and bifascicular conduction block, and compared empiric pacemaker implantation with a monitoring strategy using an implantable loop recorder 6.
Key Findings
- Prophylactic pacing may not be necessary in asymptomatic patients with bifascicular block 3, 4.
- The risk of complete heart block in patients with bifascicular block is low 3, 4.
- Transcutaneous pacing is safe and effective in patients with asymptomatic chronic bifascicular block or left bundle branch block 2.
- An additional first-degree atrioventricular block does not increase the risk of severe bradyarrhythmias in patients with bifascicular block or left bundle branch block 4.
- The optimal management strategy for patients with syncope and bifascicular conduction block is still being studied 6.