Feasibility, safety and outcomes of upgrading to left bundle branch pacing in patients with right ventricular pacing induced cardiomyopathy

Abstract Funding Acknowledgements Type of funding sources: None. Background Right ventricular pacing (RVP) induces abnormal electrical activation and asynchronous ventricular contraction and leads to pacing induced cardiomyopathy (PICM) in 10-20% of patients. Cardiac resynchronization therapy (CRT) utilizing biventricular pacing (BVP) is the recommended treatment. Left bundle branch pacing (LBBP) is a novel physiological pacing technique which may serve as an alternative to CRT. This study assessed feasibility and outcomes of LBBP delivered CRT in patients with PICM. Methods Twenty consecutive patients with PICM who received an upgrade of their pacemaker to LBBP were prospectively studied. Acute success rate, complications, functional and echocardiographic response and hospitalization for heart failure within six months from implantation were evaluated. Results LBBP was successfully delivered in all patients. Median duration of RVP before upgrade to LBBP was 3.8 years and the RVP percentage was 99. LBBP resulted in significant QRS narrowing (from 192 ± 18 to 131 ± 17 ms (p<0.001)), improvement in LVEF (from 31 ± 6 percent to 44 ± 8 percent (p<0.001)) and NYHA class (from 2.7 ± 0.5 to 1.4 ± 0.5 (p<0.001)) at 6 months. No LBBP-related complications occurred and no hospitalization for heart failure or death occurred. Conclusion LBBP is feasible and safe in delivering CRT in PICM. Preliminary analyses demonstrated significant electrical resynchronization and favourable improvement in LV function and NYHA functional class at short term follow-up. Data need to be validated in large randomized controlled trials.