Rethinking atrial pacing support in cardiac resynchronization therapy: insights from the CRT-NEXT trial.

Cardiac resynchronization therapy defibrillators traditionally require a dedicated right atrial lead to provide atrial sensing and pacing in addition to biventricular pacing. However, the clinical value of routine atrial pacing in CRT recipients without sinus node dysfunction remains uncertain, while additional transvenous leads increase procedural complexity and lead-related complications. The CRT-NEXT trial evaluated whether a simplified two-lead CRT-DX system, capable of atrial sensing through a floating atrial dipole but without atrial pacing, was non-inferior to conventional three-lead CRT-D. In this randomized non-inferiority trial, CRT-DX met the prespecified non-inferiority criterion for the composite endpoint of all-cause mortality, cardiovascular hospitalization, and lead-related complications at 12 months. Mortality, cardiovascular hospitalization, arrhythmic outcomes, reverse remodeling, and functional capacity were comparable between groups, while CRT-DX was associated with shorter procedure time and fewer atrial lead-related complications. Importantly, atrial sensing remained reliable during follow-up, CRT delivery was preserved, and only one patient required late atrial lead implantation. These findings challenge the routine need for atrial pacing support in carefully selected CRT-D candidates and suggest that reliable atrial sensing may be sufficient for most patients without sinus node dysfunction. Future integration of DX-based atrial sensing with conduction system pacing may further advance device simplification toward single-lead CRT-D platforms.