Conduction System Pacing Inferior to BiVP for Outcomes in HFrEF with LBBB, Finds Study

Cardiac resynchronization therapy is a key treatment for patients with HFrEF and electrical dyssynchrony, such as LBBB. While biventricular BiVP is the standard approach, CSP, particularly left bundle-branch area pacing, has emerged as a potentially more physiological and cost-effective alternative. However, its effect on major heart failure outcomes remains uncertain.

To examine this, André Zimerman and colleagues conducted the PhysioSync-HF trial, an investigator-initiated, multicenter, noninferiority randomized clinical study across 14 hospitals in Brazil. Adults with symptomatic HFrEF (New York Heart Association class II–III), LVEF ≤35%, and LBBB with QRS duration ≥130 milliseconds were enrolled between November 2022 and December 2023 and followed for 12 months.

The study included 173 patients (median age 62 years; 49.7% women), with about two-thirds having dilated cardiomyopathy. The median baseline LVEF was 26%, and the median QRS duration was 180 milliseconds. Participants were randomly assigned in a 1:1 ratio to receive either CSP—preferably left bundle-branch area pacing—or conventional BiVP.

The primary outcome was a hierarchical composite of all-cause death, heart failure hospitalizations, urgent heart failure visits, and change in LVEF at 12 months, with a prespecified noninferiority margin set at an odds ratio of 1.2.

The authors noted several limitations, including differences in care across participating centers and the possibility of a learning curve, as operators had less experience with CSP than with BiVP. The moderate sample size and relatively few clinical events also indicate that larger studies are needed to further evaluate these findings.

Reference:

Zimerman A, dal Forno A, Rohde LE, et al. Conduction System vs Biventricular Pacing in Heart Failure: The PhysioSync-HF Randomized Clinical Trial. JAMA Cardiol. Published online March 11, 2026. doi:10.1001/jamacardio.2026.0101