From the Guidelines
For patients with bifascicular block and syncope, a permanent pacemaker implantation is recommended, especially if other causes of syncope have been excluded, as it can significantly reduce the risk of syncope recurrence, as shown in the PRESS trial 1.
Key Considerations
- Bifascicular block is a cardiac conduction abnormality that affects the heart's electrical conduction system, potentially leading to complete heart block.
- Patients with bifascicular block may be asymptomatic, but the condition requires monitoring as it can progress to complete heart block.
- For symptomatic patients experiencing syncope, presyncope, or documented high-degree AV block, a permanent pacemaker implantation is typically indicated.
- The European guidelines recommend a strategy of ILR if prior EPS findings are unremarkable, while the U.S. guidelines recommend ILR implantation for syncope suspected to be of an arrhythmic etiology 1.
Management Approach
- Asymptomatic patients with bifascicular block require regular cardiac follow-up with ECG monitoring.
- Symptomatic patients with bifascicular block and syncope should undergo further evaluation, including EPS and/or prolonged monitoring with ILR, to determine the underlying cause of syncope.
- A permanent pacemaker implantation is recommended for patients with bifascicular block and syncope, especially if other causes of syncope have been excluded, as it can significantly reduce the risk of syncope recurrence, as shown in the PRESS trial 1.
Important Studies
- The PRESS trial demonstrated a significant absolute 20% reduction of syncope recurrence with cardiac pacing in patients with bifascicular block and syncope 1.
- The European guidelines recommend EPS-guided pacemaker implantation for patients with bifascicular block and syncope, based on evidence that this strategy results in a parsimonious pacemaker implantation with rare syncope recurrence in paced patients 1.
From the Research
Definition and Risks of Bifascicular Block
- Bifascicular block is a condition where there is a blockage in two of the three main electrical conduction pathways of the heart, which can increase the risk of complete heart block [(2,3)].
- The risk of progression to complete heart block is a primary concern in patients with bifascicular block, and an additional first-degree A-V block may increase this risk 3.
Perioperative Risks and Management
- Patients with bifascicular block undergoing anesthesia may be at risk of developing complete heart block or other conduction defects [(2,3,4)].
- However, studies have shown that the incidence of perioperative bradyarrhythmias in patients with bifascicular block is relatively low, and routine prophylactic insertion of a temporary pacemaker may not be necessary [(2,5)].
- Transesophageal pacing has been successfully used to manage complete atrioventricular block in patients with bifascicular block during anesthesia 4.
Evaluation and Treatment of Bifascicular Block in Unexplained Syncope
- The presence of bifascicular block on electrocardiography may suggest that unexplained syncope is due to complete heart block, and European Society of Cardiology (ESC) guidelines recommend investigating it with electrophysiology study (EPS) 6.
- However, a single-center audit found that adherence to these guidelines was low, with only 10.3% of patients undergoing guideline-directed evaluation 6.
- Cardiology consultation and evaluation with EPS and/or implantable loop recorder (ILR) are important for guiding treatment, including the potential use of permanent pacemakers (PPM) 6.