Three-year trajectory of ventricular function recovery in newly diagnosed heart failure with reduced ejection fraction using a wearable cardioverter-defibrillator

Background In patients with de novo heart failure with reduced ejection fraction (HFrEF), improvement of left ventricular ejection fraction (LVEF) is expected when guideline-directed medical therapy is initiated. Previous studies have demonstrated LVEF improvement up to one year, but longer-term follow-up data remain limited. Purpose To assess changes in left ventricular function over a three-year follow-up in newly diagnosed HFrEF patients prescribed a wearable cardioverter-defibrillator (WCD). Methods Between April 2017 and July 2025, among 188 patients prescribed a WCD at our institution, we identified 61 newly diagnosed heart failure patients with baseline LVEF ≤35% who had echocardiographic data available at 3 months, 1 year, and 3 years. Changes in ventricular function were analyzed. Results The mean age was 60.6±11.4 years, and 46 patients (75.4%) were male. The mean body mass index was 24.6±9.0 kg/m2. Seventeen patients (27.9%) had ischemic cardiomyopathy, while 37 (60.7%) of the non-ischemic cohort had dilated cardiomyopathy. WCD was prescribed for primary prevention in 50 patients (82.0%) , and no appropriate shock therapies were delivered. Beta-blockers were prescribed in 98.4%, renin-angiotensin system inhibitors in 100%, mineralocorticoid receptor antagonists in 91.8%, and sodium-glucose cotransporter 2 inhibitors in 63.9% of patients. All patients had a baseline LVEF ≤35%, and improvement to >35% was observed in 49.2% at 3 months, 67.2% at 1 year, and 70.5% at 3 years (p<0.001). A significant difference was observed between 3 months and 1 year (p<0.05), but not between 1 year and 3 years (p=0.625). Conclusion Although WCD prescription is limited to 3 months, improvement of LVEF can be expected during the first year of follow-up, while no significant improvement was observed beyond one year.