Conduction System vs Biventricular Pacing in Heart Failure: The PhysioSync-HF Randomized Clinical Trial

Area of Science:

• Cardiology
• Electrophysiology
• Heart Failure Management

Background:

• Conduction system pacing (CSP) presents a potential alternative to biventricular pacing (BiVP) for heart failure patients with reduced ejection fraction (HFrEF) and left bundle-branch block (LBBB).
• The comparative efficacy of CSP versus BiVP on heart failure (HF) outcomes in this specific patient population remains incompletely understood.
• Investigating novel pacing strategies is crucial for optimizing treatment and improving outcomes in HFrEF patients with LBBB.

Purpose of the Study:

• To compare the effectiveness of CSP against BiVP in patients diagnosed with HFrEF and LBBB.
• To evaluate the impact of CSP versus BiVP on key heart failure-related clinical outcomes.
• To determine the noninferiority of CSP compared to BiVP for HF management in this cohort.

Main Methods:

• A multicenter, noninferiority randomized clinical trial (PhysioSync-HF) was conducted.
• Adult patients with symptomatic HFrEF (NYHA classes II-III), LVEF ≤35%, and LBBB (QRS ≥130 ms) were randomized 1:1 to CSP or BiVP.
• The primary outcome was a composite of death, HF hospitalizations, urgent HF visits, and change in LVEF at 12 months.

Main Results:

• CSP failed to demonstrate noninferiority and was found to be inferior to BiVP for the primary composite endpoint (OR, 2.36; P=.002).
• The composite of death, HF hospitalizations, or urgent HF visits occurred more frequently with CSP (HR, 2.35).
• While both pacing methods improved LVEF, QRS duration, and quality of life metrics, BiVP showed a statistically significant greater increase in LVEF.
• CSP was associated with lower direct medical costs compared to BiVP.

Conclusions:

• In patients with HFrEF and LBBB, CSP was inferior to BiVP regarding a composite of major HF events and LVEF change at 12 months.
• The study findings do not support the routine use of CSP as the initial resynchronization strategy for this patient group.
• Further research may be needed to identify specific subgroups who might benefit from CSP or to refine CSP techniques.