Impact of tricuspid regurgitation in patients undergoing left bundle branch area pacing for cardiac resynchronization therapy

Introduction Left bundle branch area pacing (LBBAP) is increasingly being used as an alternative cardiac resynchronization strategy. Recently, LBBAP has been associated with an increased risk in tricuspid regurgitation (TR). Whether this has an impact on clinical outcomes is yet to be determined. Purpose To determine the incidence and impact of TR in patients undergoing LBBAP for CRT. Methods Patients with heart failure with a left ventricular ejection fraction <40% undergoing LBBAP between September 2020 and March 2025 were included. TR was graded according to standard criteria (1); significant TR was defined as moderate or severe TR. The prevalence of preprocedural TR, changes in TR (unchanged, improved, worsening to significant) and their impact on the composite outcome of HF-related hospitalization and all-cause mortality, were evaluated. Results A total of 257 patients (female 30.7%, age 69.3±9.9 years) with a median follow-up of 522 [286-855] days, were included. 104 patients (40.5%) had significant TR before the procedure. Preprocedural TR was associated with a higher incidence of the composite outcome (HR 1.69, 95% CI 1.11-2.6, Log Rank P 0.005) (Figure 1); however, patients with preexistent TR had a higher prevalence of atrial fibrillation (64.4% vs. 39.7%, p<0.001), a lower prevalence of coronary artery disease (30.8% vs. 45.1%, p=0.027), and were less likely to receive iSLT2 (69.4% vs- 82.4%, p=0.016) or ARNI (49% vs. 35.6%, p=0.04) respectively. After the procedure, 43.2% of patients had no significant change in TR, 25.7% had improved TR, and 19.5% of patients had worsening to significant TR; postprocedural TR evaluation was not available in 11.5% of patients, due to lack of insurance or patient decision (21 patients, 8.2%) or early death (6 patients, 2.3%). During follow-up, there were no significant differences in the composite outcome of HF-related hospitalization and all-cause mortality according to the change in TR (Log Rank p=0.779)(Figure 2). Conclusions In patients undergoing LBBAP CRT, worsening TR occurs in a significant proportion of patients. However, in this study, worsening TR was not associated with significantly worse clinical outcomes compared to patients with improved or unchanged TR. Our results suggest that in the setting of LBBAP CRT, worsening TR does not appear to be a major determinant of clinical outcomes.Figure 1Figure 2