Cardiac resynchronization therapy (CRT) can reverse left ventricular dysfunction caused by right ventricular pacing in patients with heart failure, but response rates vary. A single-center observational study presented at ESC 2025, examined this theory.

The study included 55 patients undergoing CRT upgrades, with a median age of 76 years. Response was defined as an increase of ≥5% in left ventricular ejection fraction (LVEF) and improvement by at least one New York Heart Association (NYHA) class.

Overall, 64% of patients responded to CRT, with a mean LVEF increase of 10.7%. The strongest responses were observed in patients with non-ischemic cardiomyopathy, age <70 years at revision, and right ventricular pacing ≥40% at baseline. Nearly all responders improved their NYHA class, with 49% reaching class I at 6–12 months follow-up. Gender, baseline rhythm, duration since initial implant, and device type were not predictive of response.

These results demonstrate the significant potential of CRT upgrades in routine clinical practice, particularly in regional hospital settings, and identify key patient factors that may guide decision-making for optimal outcomes.