Background: Transcatheter aortic valve implantation (TAVI) has become a well-established treatment for patients with severe aortic stenosis who are at intermediate or high surgical risk. Despite procedural advances, post-procedural conduction disturbances remain among the most common complications, particularly new-onset left bundle branch block (LBBB). This study aimed to investigate the impact of balloon pre- and post-dilatation on the cardiac conduction system during TAVI.

Methods: A retrospective analysis was conducted on 447 consecutive patients who underwent successful TAVI between June 2021 and June 2025. After excluding patients with baseline bundle branch block or permanent pacemaker rhythm, 282 patients were included. Standard 12-lead electrocardiograms were evaluated before and after TAVI. Post-procedural QRS prolongation was defined as QRS >120 ms, and logistic regression analysis was performed to identify predictors.

Result: The mean age was 76.5 ± 6.9 years, and 63.8% of patients were female. Larger prosthesis diameter (OR = 1.173, 95% CI 1.082-1.271; P < .001) and post-dilatation (OR = 2.147, 95% CI 1.235-3.733; P = .007) were independently associated with QRS prolongation. Post-dilatation specifically correlated with new-onset LBBB but not with right bundle branch block (RBBB), intraventricular conduction delay, or high-grade atrioventricular (AV) block. No significant predictors were identified for permanent pacemaker implantation.

Conclusion: Balloon post-dilatation during TAVI is an independent risk factor for the development of new-onset LBBB. Patients with pre-existing conduction abnormalities, such as RBBB or first-degree AVr block, should be monitored closely after post-dilatation, as LBBB may adversely affect left ventricular function and long-term clinical outcomes.