The impact of persistent LBBB After TAVI: unraveling its effect on cardiac function and survival

Introduction Cardiac conduction abnormalities frequently occur after transcatheter aortic valve implantation (TAVI). While the need for a permanent pacemaker (PM) is a recognized concern, new-onset left bundle branch block (LBBB) is also prevalent and may impact clinical outcomes. Aims To assess the incidence and persistence of new-onset LBBB after TAVI, its impact on left ventricular ejection fraction (LVEF), and its effect on survival. Methods Single-center retrospective cohort analysis of TAVI patients from January 2010 to January 2022. Primary outcomes included LBBB development, LBBB persistence, 1-year LVEF variation, and all-cause mortality. Results Of 552 patients, 431 were included after excluding those with prior PM (n=52), LBBB (n=30), or right bundle branch block (RBBB) (n=39). During hospitalization, 165 patients (38.3%) developed LBBB, 43 (10.1%) required PM implantation, and 7 (1.6%) developed RBBB. At 1-month follow-up, LBBB persisted in 69 cases (41.8%), with 2 additional patients developing persistent LBBB. Among the remaining new-onset LBBB cases, 38 (23%) underwent PM implantation, while LBBB resolved in 58 (35.8%). Patients with persistent LBBB exhibited a 6.2% lower LVEF variation at 1-year follow-up (95% CI: -8.1%, -4.5%, p<0.001) compared to those without rhythm disturbances. New-onset left ventricular dysfunction was significantly higher in persistent LBBB patients (16.9%) compared to only 0.01% in those without rhythm disturbances (p<0.001). In contrast, patients with transient LBBB showed no significant impact on LVEF evolution (p=0.295). Patients with persistent LBBB had a median survival of 58 months (±5.4), significantly lower than the 94 months (±10.4) observed in those without rhythm disturbances (p<0.001). When combining transient and persistent LBBB cases, no significant mortality differences were identified (p=0.431). Demographic parameters and comorbid conditions were well balanced between groups, with a median age of 81 years [IQR: 75-85], and 56% female. Conclusion Our study highlights the high prevalence and clinical impact of new-onset LBBB after TAVI. Nearly half of new-onset LBBB cases persisted, correlating with worsened LVEF and increased mortality. Recognizing LBBB risk pre-TAVI is crucial for informed treatment decisions, while closer post-TAVI monitoring is key for identifying those who may benefit from resynchronization therapy.