When to implant an ICD in patients with heart failure and reduced ejection fraction? Insights from the HF-OPT trial

Background In patients with de novo heart failure with reduced ejection fraction (HFrEF) improvement of left ventricular ejection fraction (LVEF) is expected to occur when started on guideline-recommended medical therapy (GRMT). However, the period of time, when LVEF improvement is completed, is unknown. Purpose Evaluation of improvement of LVEF >35% within the first year after de novo diagnosis of HFrEF with severely reduced LVEF <35%. Methods In the prospective HF-OPT-trial, patients with de novo HFrEF and LVEF ≤35% prescribed the wearable cardioverter defibrillator (WCD) were enrolled and followed up to one year. GRMT was initiated and uptitrated according current guidelines. LVEF improvement >35% under GRMT was echocardiographically assessed at day 0, day 90, day 180 and day 360. Results A total of 487 patients (59 years (IQR: 51-68), 27% women) were followed until day 180. Out of 487 patients 392 patients were followed additionally to day 360. Dosages of GRMT were significantly increased during follow-up (p<0.001) At 90 days, 46% (CI: 41%-50%) of the patients had LVEF improvement >35%. About half of those with persistently LVEF<35% at day 90 (46%, CI: 40%-52%) had LVEF improvement >35% by day 180, increasing the total rate of improvement >35% to 68% (CI: 63% - 72%). Until day 360 the rate of LVEF improvement >35% increased to 78%. Conclusions 78% of patients with de novo HFrEF showed improvement in LVEF >35% during the first year after diagnosis following GRMT. This finding impacts decision making for primary preventive ICD implantation.Development of LVEF.