Refining Patient Selection Criteria for LV-Only Fusion Pacing in Cardiac Resynchronization Therapy: A Systematic...

Objectives: This review aims to systematically evaluate the clinical outcomes of left ventricle-only fusion pacing (LV-only fCRTp) and identify evidence-based selection criteria that may optimize patient response and long-term therapeutic benefit. Background: Cardiac resynchronization therapy (CRT) is traditionally associated with biventricular pacing (BiVp). However, approximately 20-40% of patients seem to remain non-responders to this therapy. LV-only fCRTp offers a more physiological alternative by combining left ventricular epicardial pacing with the intrinsic ventricular activation wavefront. Beyond optimization strategies, the observed variability in response highlights the need for better patient selection in order to fully unlock its therapeutic potential. Methods: A systematic literature search was conducted in PubMed and Cochrane Library for original articles published up to April 2025, following PRISMA 2020 guidelines. The search focused on LV-only fCRTp performed either through standard RA/LV/RV biventricular devices or RA/LV dual-chamber systems. Results: Twenty-seven studies met the inclusion criteria. Among these, 17 studies obtained LV-only fCRTp using biventricular devices, and 10 were considered true LV-only fCRTp using RA/LV dual-chamber devices. Standard and specific selection criteria were used to qualify patients for LV-only fCRTp. Preserved atrioventricular conduction, ischemic cardiomyopathy, arrhythmic risk stratification, and the management of supraventricular arrhythmias were common overlapping parameters among studies with high variability, highlighting their potential role in response. RA/LV devices yielded consistent clinical benefits and low complication rates, particularly in nonischemic patients with stable AV conduction and low arrhythmic risk, while having a lower financial burden. Conclusions: Beyond guideline recommendations for CRT, this review identifies supplementary selection criteria that could further influence the effectiveness and stability of fusion pacing.