Comparisons of Long-Term Clinical Outcomes with Left Bundle Branch Pacing, Left Ventricular Septal Pacing and Biventricular Pacing for Cardiac Resynchronization Therapy

Background Left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are referred to as left bundle branch area pacing (LBBAP). Objective This study investigated whether long-term clinical outcomes differ in patients undergoing LBBP, LVSP, and biventricular pacing (BiVP) for cardiac resynchronization therapy (CRT). Methods Consecutive patients with reduced left ventricular ejection fraction (LVEF<50%) undergoing CRT were prospectively enrolled if they underwent successful LBBP, LVSP, or BiVP. The primary composite endpoint was all-cause mortality or heart failure hospitalization (HFH). Secondary endpoints included all-cause mortality, HFH, and echocardiographic measures of reverse remodeling. Results A total of 259 patients (68 LBBP, 38 LVSP, and 153 BiVP) were followed for a mean duration of 28.8 ± 15.8 months. LBBP was associated with a significantly reduced risk of the primary endpoint by 78% compared to both BiVP [7.4% vs. 41.2%; adjusted hazard ratio (aHR) 0.22 (0.08, 0.57), p=0.002] and LVSP [7.4% vs. 47.4%; aHR 0.22 (0.08, 0.63), p=0.004]. The adjusted risk of all-cause mortality was significantly higher in LVSP than BiVP [31.6% vs. 7.2%, aHR 3.19 (1.38, 7.39); p=0.007] but comparable between LBBP and BiVP [2.9% vs. 7.2%, aHR 0.33 (0.07, 1.52), p=0.155]. Propensity score adjustment also obtained similar results. LBBP showed a higher rate of echocardiographic response (ΔLVEF ≥10%: 60.0% vs. 36.2% vs. 16.1%; p<0.001) than BiVP or LVSP. Conclusion LBBP yielded superior long-term clinical outcomes to BiVP and LVSP. The role of LVSP for CRT needs to be reevaluated due to its high mortality risk.