Study finds: ICD implantation may reduce the risk of sudden death in some patients under 70 years old with mild to moderate cardiac dysfunction

2026/09/09 14:41

The study found that ICDs may benefit some patients under the age of 70 who have mild to moderate heart dysfunction and myocardial scarring. The picture shows a schematic diagram. (Extracted from shutterstock)

[Compiled by Xie Yizhe/Comprehensive Report] An Australian-led international study found that implantable cardioverter defibrillators (ICDs) may benefit some patients under the age of 70 who suffer from mild to moderate cardiac dysfunction and myocardial scarring. The study was published in the Journal of the American Medical Association.

According to the science website "SciTechDaily", an ICD is a small device implanted in the human body that can detect and correct dangerous heart rhythm abnormalities that may further lead to sudden cardiac death. Current treatment guidelines mainly believe that only patients with severely reduced cardiac function are suitable for ICD implantation. In this regard, Joseph Selvanayagam, professor of cardiovascular medicine at Flinders University in Australia, and his team tested whether ICDs can also benefit patients with milder conditions.

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The study was conducted at 18 research centers in Australia, Germany and the United Kingdom. The subjects were patients with mild to moderate cardiac dysfunction, left ventricular ejection fractions of 36% to 50%, and myocardial scarring detected by cardiac magnetic resonance. The research team implanted ICDs in such patients and observed whether it could reduce the incidence of sudden cardiac death or severe ventricular arrhythmias.

The analysis showed that when patients of all ages were combined, ICD implantation did not significantly reduce the overall incidence of sudden cardiac death or severe ventricular arrhythmia. However, the research team further analyzed sudden cardiac death separately and found that ICD implantation was associated with a significantly lower risk of sudden cardiac death in the overall study population.

The research team also noted that in a prespecified group analysis before the start of the study, patients under the age of 70 had a significantly lower incidence of sudden cardiac death or severe ventricular arrhythmia.

The research team stated that most patients who died suddenly due to cardiac events did not actually have severe cardiac dysfunction. Because these patients did not meet current accepted treatment guidelines during their lifetime, they are usually not provided with an ICD. The findings of this study provide important new information for individual patient treatment decisions.

The research team added that if someone has a mild to moderate decline in heart function due to cardiomyopathy or myocardial infarction, they should undergo a cardiac magnetic resonance examination.