Study title: ICDs in patients with severe LV systolic dysfunction: REFINE-ICD

Presented at: ESC 2025

Link: https://www.escardio.org/Congresses-Events/ESC-Congress/Congress-resources/Congress-news/Hot-Line-3-REFINE-ICD

Prepared by: Dr. Kemal Göçer

Introduction
After myocardial infarction (MI), patients with moderate left ventricular systolic dysfunction (LVEF 36–50%) and abnormal electrocardiographic (ECG) markers such as impaired heart rate turbulence and T-wave alternans have a poor prognosis. It was unknown whether implantable cardioverter defibrillators (ICDs) would provide additional benefit in this population.

Study Design
This was an international, investigator-initiated, randomized trial. About 2000 post-MI patients who were at least two months from the event were screened. A total of 597 patients with high-risk ECG findings were randomized into two groups: ICD plus optimal medical therapy or optimal medical therapy alone. The mean follow-up duration was 5.7 years.

Results
Patients with high-risk markers had a 2.5-fold higher risk of death compared to those without (HR 2.59; p<0.001). However, when comparing randomized groups: overall mortality was 24.5% in the ICD arm vs. 21.3% in the control arm (HR 1.07; p=0.69); cardiac mortality was 8.8% vs. 7.6% (HR 1.11; not significant); and sudden cardiac death was 2.6% vs. 3.8% (HR 0.66; not significant). Nearly half of all deaths (47.4%) were due to non-cardiac causes.

Conclusion
In this high-risk ECG subgroup, ICD implantation did not reduce overall or cardiac mortality. The observed mortality risk was lower than expected, with a large proportion of deaths due to non-cardiac causes.

Commentary
REFINE-ICD demonstrates that routine ICD implantation in post-MI patients with moderate LVEF reduction and abnormal ECG markers does not provide clear benefit. Clinically, this highlights the need for more selective strategies and novel risk stratification methods in this patient group.