Pacemaker Implantation in Patients With Pre-Existing Bundle Branch Block Undergoing Balloon-Expandable Transcatheter...

Area of Science:

• Cardiology
• Interventional Cardiology
• Cardiac Electrophysiology

Background:

• Transcatheter aortic valve replacement (TAVR) is a common procedure for aortic stenosis.
• Pre-existing bundle branch block (BBB) can influence outcomes after TAVR.
• Right bundle branch block (RBBB) and left bundle branch block (LBBB) have different implications for pacemaker implantation.

Purpose of the Study:

• To compare permanent pacemaker (PPM) implantation rates after balloon-expandable TAVR between patients with RBBB and LBBB.
• To evaluate long-term clinical outcomes based on baseline conduction status and post-TAVR PPM implantation.
• To identify predictors of PPM implantation post-TAVR.

Main Methods:

• Retrospective study of 380 patients undergoing balloon-expandable TAVR (2016-2020).
• Patients were stratified into pre-existing RBBB (n=269) and LBBB (n=111) groups.
• Exclusion criteria included prior pacemaker or implantable cardioverter-defibrillator use.

Main Results:

• Higher 30-day PPM implantation rates in RBBB vs. LBBB patients (18.59% vs. 7.21%, p=0.003).
• RBBB patients had larger annular dimensions, greater calcification, and narrower membranous septum angle.
• No significant 2-year differences in mortality or heart failure hospitalization between groups, irrespective of PPM status.
• Baseline RBBB (OR 3.56) and prior atrial fibrillation/flutter (OR 4.13) predicted increased 30-day PPM risk.

Conclusions:

• Pre-existing RBBB significantly increases early PPM implantation rates after balloon-expandable TAVR compared to LBBB.
• Long-term clinical outcomes are comparable between RBBB and LBBB patients, regardless of PPM implantation.
• Risk factors for PPM include RBBB and atrial fibrillation/flutter; deeper valve implantation may reduce risk.