Implantable Cardioverter Defibrillators Show No Mortality Benefit in Certain Heart Attack Patients

Recent research presented at ESC Congress 2025 has questioned the effectiveness of implantable cardioverter defibrillators (ICDs) in reducing mortality among specific heart attack survivors. The study focused on patients with a history of myocardial infarction (MI), who also exhibited persistent moderate left ventricular (LV) systolic dysfunction and abnormal ECG markers indicative of increased arrhythmia risk.

The large, international REFINE-ICD trial involved nearly 2,000 post-MI patients across North America, Europe, the Middle East, and Africa. Participants underwent ambulatory ECG testing, assessing indicators like heart rate turbulence and T wave alternans, which are known to predict ventricular arrhythmias. Out of these, 597 patients with LVEF between 36-50%, impaired heart rate turbulence, and abnormal T wave alternans were randomized to receive a defibrillator along with optimal medical therapy or medical therapy alone.

The median age was 65 years, with 19% women. Overall, patients with both abnormal markers faced a higher risk of death. However, over an average follow-up of about 5.7 years, the study found no significant reduction in mortality due to ICD implantation. Deaths occurred at similar rates in both groups—24.5% in those with ICDs and 21.3% in the control group. Notably, nearly half of all deaths were non-cardiac, highlighting other factors influencing prognosis. Cardiac deaths and sudden cardiac death rates did not differ significantly between groups, indicating that the ICD did not provide a survival advantage for this patient subset.

Professor Derek Exner, lead investigator, summarized the findings, emphasizing that patients with prior MI, moderate LV dysfunction, and arrhythmia risk markers had a doubled risk of death compared to those without these risks. Yet, despite the higher risk profile, ICD therapy did not lead to a reduction in mortality or sudden cardiac death, suggesting a need to rethink intervention strategies for these patients. Further research is crucial to identify more effective methods for improving long-term outcomes in this high-risk group.

This study adds valuable insight into the ongoing evaluation of ICD utility beyond traditional indications and underscores the importance of personalized approaches to post-MI treatment.

Source: https://medicalxpress.com/news/2025-09-implantable-cardioverter-defibrillators-mortality-heart.html