CMR GUIDE missed its main target and found a signal under age 70
The CMR GUIDE work tested whether an implantable device lowers sudden-death risk in people with magnetic-resonance scar and a left ventricular ejection fraction of 36 per cent to 50 per cent. The main measure showed no difference across the whole group, while a reduction stood out in those younger than 70. Commentators said scar imaging alone does not settle the device decision and that device trials must move overall death rather than arrhythmic death alone.
Science··Midday
The main measure showed no difference with scar and mid-range ejection fraction
The CMR GUIDE work compared an implantable device with a recorder in 353 people with ischaemic or non-ischaemic cardiomyopathy who had magnetic-resonance scar and a left ventricular ejection fraction of 36 per cent to 50 per cent. The main measure was time to sudden cardiac death or significant ventricular tachycardia. Across the full group, the device did not produce a clear difference on that measure. The study ran at 18 sites in Australia, Germany and the United Kingdom, testing defibrillator use one step before the severe pump-failure range where these devices are usually offered.[1], [2]
A reduction stood out in those younger than 70
In people younger than 70, a reduction on the main measure did stand out. That age pattern came from a subgroup rather than the outcome named in advance, so it describes a group worth testing again rather than a settled use rule. On its own, sudden cardiac death did fall across the whole cohort. What looked promising in scar imaging did not carry through to the trial's declared success criterion for the full population.[1], [2]
Scar imaging alone does not settle the decision
Published commentary around the result said belief in the scar-imaging theory now runs ahead of what the trial showed. Scar imaging alone does not settle the device decision, one line of debate argued; trials of these devices should aim to reduce overall death, not arrhythmic death alone. The findings were presented at the European Society of Cardiology Congress in Munich and appeared in JAMA. Investigators led from Flinders University in Adelaide described the age signal as worth further study rather than as proof that every person with scar and mid-range ejection fraction should receive a device.[2], [1]
