Multisite pacing upgrade for refractory heart failure in dual-chamber pacemaker recipients: a single-center experience of 71 cases

Background Prolonged right ventricular (RV) pacing in dual-chamber pacemaker recipients can induce electrical and mechanical dyssynchrony, leading to pacing-induced cardiomyopathy, compromised systolic function, and symptoms of heart failure (HF). The upgrade to Multisite Pacing (MSP), or Cardiac Resynchronization Therapy, is a physiological approach aimed at restoring cardiac synchrony and optimizing hemodynamic performance. Studies demonstrate its potential to improve ejection fraction and functional status. Objective This study evaluates the clinical and hemodynamic outcomes of a cohort of patients who underwent an upgrade from a dual-chamber pacemaker to Multisite Pacing at a specialized center. Methods Between March 2006 and October 2025, 914 MSP devices were implanted at our service. This analysis focused on 71 patients who were upgraded from a dual-chamber pacemaker to MSP due to a widened QRS complex secondary to chronic RV apical pacing, ventricular dyssynchrony, and persistent HF symptoms despite optimized medical therapy. The procedure involved coronary sinus cannulation via the femoral vein and left subclavian vein punctures for lead insertion, followed by venography to optimize the left ventricular lead position. Device programming targeted the shortest possible QRS interval. Patient characteristics and post-upgrade follow-up data, particularly regarding ejection fraction (EF), were collected. Results The 71 upgraded patients represented 7.8% of the total MSP implantations. The mean age was 60.5 years (range 45 to 76 years), and 64.8% were male. Underlying etiologies included Chagas Disease (47.9%), Coronary Artery Disease (22.5%), and Valvular Heart Disease (11.3%). The overall technical and clinical success rate for the upgrade procedure was 77.5%. Notably, there were no reported complications during or after the procedure. Of the patients, 77.5% received a system associated with an Implantable Cardioverter-Defibrillator (CRT-D). In 52 patients, there was a significant increase in Ejection Fraction (EF) of 73.2% after 12 months of follow-up. Conclusion The upgrade from a dual-chamber pacemaker to Multisite Pacing is an effective and safe intervention, demonstrating a high success rate and a clinically significant improvement in Ejection Fraction (73.2%) in patients with pacing-induced dyssynchrony and refractory heart failure, confirming relevant hemodynamic and functional benefits.