Better responses by combination of left bundle branch area pacing and cardiac resynchronization therapy in heart failure patients

Background Left bundle branch-optimized CRT (LOT-CRT), combining left bundle branch area pacing (LBBAP) with coronary venous pacing, may enhance resynchronization.WE aimed to compare LOT-CRT efficacy versus conventional biventricular CRT (BiV-CRT) or LBBAP-only. Methods This prospective study included 70 patients (66 ± 9 years, 68.6% male) (30 LOT-CRT, 40 BiV-CRT). Apart from QRS duration (QRSd), interventricular mechanical delay (IVMD), peak strain dispersion (PSD), global longitudinal strain (GLS) and myocardial work (MW) as global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were assessed by speckle-tracking echocardiography. LOT-CRT responders were switched to LBBAP-only mode for one month. Results During 6-month follow-up, the LOT-CRT group had a more profound reduction in QRSd (42.0 [23.3, 74.5] vs. 17.0 [16.3, 23.8]ms, P < 0.001) and PSD (72.0 [43.0, 114.3] vs. 35.5 [4.3, 82.0]ms, P = 0.001). Similar improvement was achieved in left ventricular ejection fraction (LVEF) (16.5 [3.8, 24.0] vs. 15.5 [5.3, 20.8]%) and GLS (-4.5 [-6.0, -3.0] vs. -3 [-6.0, -1.3]%) but the LOT-CRT group displayed better increase in GWE (24.0 [11.0, 29.3] vs. 10.0 [6.3, 14.8] %, P < 0.001). Both echocardiographic and clinical responses were achieved in 66.7% patients receiving LOT-CRT and 72.5% receiving BiV-CRT (P = 0.598). After switching to LBBAP, LOT-CRT responders (n = 20) showed QRSd widening (131.5 ± 26.4 vs. 142.2 ± 29.4ms, P < 0.001) accompanied by worsening LVEF (55.6 ± 7.7 vs 51.1 ± 7.7%, P = 0.002) and GLS (-10.9 ± 2.8 vs. -10.0 ± 2.3%, P = 0.006). Conclusions LOT-CRT represented as a viable alternative to BiV-CRT with superior intraventricular resynchronization, whereas LBBAP alone failed to maintain the benefits in cardiac synchrony and function of LOT-CRT. Trial registration: This study was registered with the Chinese Clinical Trial Registry (ChiCTR) at http://www.chictr.org.cn/ (registration number: ChiCTR2500110771).