ICDs May Benefit Younger Patients With Mild-to-Moderate Heart Dysfunction, CMR GUIDE Trial Finds
核心洞察
The CMR GUIDE trial found that implantable cardioverter-defibrillators (ICDs) did not significantly improve the primary endpoint overall in patients with LVEF 36–50% and myocardial scarring.
A prespecified subgroup analysis showed ICD implantation was associated with a 72% reduction in the primary endpoint among patients younger than 70 years.
The secondary endpoint of sudden cardiac death (搜索) was significantly reduced in the ICD group compared with the implantable loop recorder (搜索) group (1.7% vs. 5.8%).
An implantable cardioverter-defibrillator (搜索) (ICD) did not improve the primary endpoint overall in the CMR GUIDE trial, but younger patients appeared to derive clinical benefit, according to results presented in a Hot Line session at ESC Congress 2026 and published simultaneously in JAMA.
Sudden death is a devastating complication of heart failure (搜索). An ICD is a small electrical device that monitors the heart rhythm continuously and delivers electrical pulses to correct abnormalities. ICDs are currently recommended to prevent sudden cardiac death (搜索) in certain patients with heart failure, namely those with left ventricular ejection fraction (LVEF) substantially reduced to 35% or less despite optimised heart failure medication. However, as noted by Principal Investigator Professor Joseph Selvanayagam from Flinders University, Flinders Medical Centre, Adelaide, Australia, most sudden cardiac deaths occur in patients with mild-to-moderate LVEF reductions who are not currently eligible for an ICD for primary prevention.
"In the CMR GUIDE trial, we assessed whether an ICD could improve outcomes in patients with LVEF 36–50% who have evidence of myocardial scarring, a risk factor for sudden cardiac death (搜索)," Professor Selvanayagam said.
Trial Design and Patient Population
The trial was conducted at 18 centres in Australia, Germany and the United Kingdom. A total of 353 patients with ischaemic or non-ischaemic cardiomyopathy (搜索), LVEF 36–50% on optimal heart failure (搜索) therapy, and myocardial scarring confirmed by cardiovascular magnetic resonance were included. Participants were randomised (1:1) to receive an ICD or an implantable loop recorder (搜索) (ILR), which monitors heart rate only. Most participants were aged over 70 years (68%), and 18% were women.
Primary and Secondary Endpoint Results
The primary endpoint of sudden cardiac death (搜索) or haemodynamically significant ventricular arrhythmias (ventricular arrhythmias producing loss of consciousness or significant drop in blood pressure) was not significantly different between the ICD and ILR groups. The primary endpoint occurred in 7.8% of patients assigned to ICDs and 9.2% assigned to ILRs (hazard ratio [HR] 0.76; 95% confidence interval [CI] 0.37 to 1.58).
In a prespecified subgroup analysis, ICD implantation was associated with a 72% reduction in the primary endpoint in patients younger than 70 years, whereas no benefit was observed in patients aged 70 years or older.
The secondary endpoint of sudden cardiac death (搜索) was significantly reduced in the ICD group compared with the ILR group (1.7% vs. 5.8%; HR 0.26; 95% CI 0.07 to 0.95).
Clinical Implications
"Overall, the primary endpoint was neutral," concluded Professor Selvanayagam. "However, younger patients appeared to derive clinical benefit from ICDs. We suggest that data from the CMR GUIDE trial are discussed with younger patients in whom ICDs may be an option in a shared decision-making process."
Finally, he remarked that data and insights from CMR GUIDE could be used to inform future trials in a larger number of patients.