Conduction system pacing vs biventricular resynchronization in heart failure with reduced ejection fraction and left bundle branch block: Rationale and design of the PhysioSync-HF Trial

Abstract

Background: Cardiac resynchronization therapy reduces heart failure hospitalizations and mortality in patients with heart failure with reduced ejection fraction (HFrEF) and left bundle branch block (LBBB). Conduction system pacing, which directly activates the His-Purkinje system, has emerged as a safe alternative to traditional biventricular resynchronization that may offer clinical benefits at lower costs.

Study design: The PhysioSync-HF trial is an investigator-led, randomized, multicenter clinical trial designed to assess whether conduction system pacing is noninferior to biventricular resynchronization on heart failure-related outcomes in patients with HFrEF and LBBB. The study population consists of 179 adults with symptomatic heart failure (New York Heart Association [NYHA] class II-III), left ventricular ejection fraction (LVEF) ≤35%, and LBBB (QRS ≥130 ms). Patients were randomized 1:1 to receive conduction system pacing or biventricular resynchronization and followed for 12 months postprocedure. The primary endpoint is a hierarchy of all-cause death, any hospitalization for heart failure, any urgent visit for heart failure, and change in LVEF from baseline. The key secondary endpoint is the mean total direct medical cost per patient. Additional endpoints include assessments of health-related quality of life, functional capacity, and safety. Enrollment began in November 2022 and concluded in December 2023.

Conclusions: PhysioSync-HF will determine whether conduction system pacing is noninferior to biventricular resynchronization on heart failure-related outcomes in patients with HFrEF with LBBB.

Registration number: NCT05572736.