His Pacing vs Biventricular Pacing for Cardiac Resynchronization Therapy: Long-Term Follow-Up From the His-Alternative I Trial

BACKGROUND: The His-Alternative I (A Randomized Trial of His Pacing Versus Biventricular Pacing in Symptomatic Heart Failure Patients With Left Bundle Branch Block) trial was the first randomized European trial to compare cardiac resynchronization therapy (CRT) delivered by His bundle pacing (His-CRT) vs CRT delivered by conventional biventricular pacing (BiV-CRT).

OBJECTIVES: The goal of this study was to compare long-term lead performance, survival, and echocardiographic response between His-CRT and BiV-CRT.

METHODS: A total of 50 patients with symptomatic heart failure (HF), left ventricular ejection fraction ≤35%, and left bundle branch block were randomized 1:1 to undergo His-CRT or BiV-CRT. Following crossover at implantation, 19 patients received His-CRT and 31 received BiV-CRT. The primary analyses were conducted by these groups, with 5 years of follow-up. Outcomes included the occurrence of reinterventions, an endpoint of all-cause mortality or hospitalization for HF, and echocardiographic response (≥15% reduction in left ventricular end-systolic volume compared with baseline).

RESULTS: The median follow-up was 5.3 years (Q1-Q3: 4.6-5.7 years). More lead revisions (37% vs 3%; P = 0.003) and generator replacements (47% vs 10%; P = 0.005) occurred in the His-CRT group compared with the BiV-CRT group. However, no statistically significant differences in reinterventions and threshold development over time were observed between the His-CRT patients with implantation thresholds ≤2.5 V/1 millisecond and the BiV-CRT group. The risk of all-cause mortality or hospitalization for HF was similar between groups (HR: 0.32; 95% CI: 0.07-1.49; P = 0.147), and echocardiographic response was comparable between the 2 groups (89% in His-CRT and 90% in BiV-CRT; P = 1.0).

CONCLUSIONS: No statistically significant difference in long-term performance was detected between His-CRT with low implantation thresholds and BiV-CRT, and echocardiographic response was comparable.