Right ventricular (RV) pacing in patients with atrioventricular (AV) block can lead to pacing-induced cardiomyopathy (PICM), higher need for cardiac resynchronization therapy (CRT) upgrade, and heart failure–related complications. Conduction system pacing (CSP) has emerged as a physiological alternative, but randomized data comparing the two strategies have been limited.

The CSPACE randomized controlled trial, published in the Journal of the American College of Cardiology, enrolled 202 patients with AV block and no baseline CRT indication. Patients were randomized 1:1 to RV septal pacing (RVsP) or CSP. Over a mean follow-up of 25.2 months, CSP reduced the composite outcome of PICM, CRT upgrade, heart failure hospitalization, and all-cause mortality compared with RVsP (7.17 vs 20.69 events per 100 person-years; HR 0.35; 95% CI 0.19–0.64; p < 0.001). The difference was driven by lower rates of PICM (HR 0.31; p = 0.002) and avoidance of CRT upgrade (p = 0.043). Rates of hospitalization (p = 0.057) and mortality (p = 0.337) were similar between groups.

CSP was associated with a higher rate of lead revision (7.9% vs 1.0%; p = 0.017), which represents a procedural limitation. Overall, CSP demonstrated superior long-term outcomes compared with RVsP in patients with AV block, supporting its consideration as an upfront pacing strategy in this population.