Cardiac Resynchronization Therapy using Left-Bundle-Branch Area and Left Ventricular Pacing

Introduction: Cardiac resynchronization therapy via biventricular pacing is an established therapy for patients with heart failure. However, high nonresponder rates and inability to predict response remains a challenge. Recently left bundle branch area pacing (LBBAP) has been shown to be feasible and may also improve clinical outcomes. In this article we describe sequential LBBAP followed by left ventricular (LV) pacing (LOT-CRT) and assess the feasibility of LOT-CRT. Methods: The RV implantation site was positioned and the LBBAP lead was implanted using our methods. The QRS duration (QRSd) at baseline, during LBBAP, biventricular pacing, and LOT-CRT was measured. Results: LOT-CRT was successful in 5 patients (age 71.8 ± 5.1 years, men 3, ischemic 3). The QRSd at baseline was 158.0 ± 13.0 ms and significantly narrowed to 117.0 ± 6.7 ms during LOT-CRT (P < 0.01). During 3-month follow-up, LV ejection fraction improved from 32.8 ± 5.2 % to 45.0 ± 5.1% (P < 0.01), and New York Heart Association functional class changed from 3.25 ± 0.5 to 2.5 ± 0.6 (P < 0.05). A decrease in left ventricular end-diastolic dimension was observed, with widening from (68.2 ± 12.3) mm at baseline to (62.2 ± 11.3) mm at pacing (P < 0.05). The length of operation time was (152.0 ± 31.1) min. Conclusions: The study demonstrates that LOT-CRT is clinically feasible in patients with systolic HF and LBBB. LOT-CRT was associated with significant narrowing of QRSd and improvement in LV function, especially in patients with ischemic cardiomyopathy.