Immediate vs delayed left bundle branch block after transcatheter aortic valve replacement: incidence and risk factors for permanent pacemaker implantation.

BACKGROUND: Characteristics of patients with delayed compared to immediate new onset left bundle branch block (LBBB) after transcatheter aortic valve replacement (TAVR) are poorly defined. OBJECTIVES: To describe the incidence and features of patients with delayed post TAVR LBBB as well as risk factors for permanent pacemaker implantation (PPI). METHODS: 1469 consecutive TAVR patients were screened for the occurrence of new onset LBBB. ECG was performed within 1 week before the procedure, immediately post procedure, and daily thereafter until discharge. According to the immediate post TAVR ECG, patients were divided into 2 groups, immediate and delayed new onset LBBB. Both groups were followed for the occurrence of PPI and mortality. RESULTS: Among patients who underwent TAVR, 296 (20.1%) developed new-onset LBBB, of whom, 282 were included the present study. LBBB occurred immediately after the procedure in 249 patients (88.3%) and was delayed in 33 patients (11.7%). Rates of both early PPI within 2 weeks as well as long term PPI and mortality were comparable between patients with immediate vs. delayed onset LBBB. In patients with immediate LBBB, QRS width correlated with a need for PPI, while in patients with delayed LBBB, PR prolongation of ≥ 115 ms differentiated between patients with and without PPI. CONCLUSIONS: The appearance of new onset post TAVR LBBB may be delayed in ~ 12% of patients. These patients exhibit similar rates of PPI need and mortality; however different ECG parameters signify high risk for PPI need among these patients.