Cardiac Magnetic Resonance Guidance of Implantable Cardioverter Defibrillator Implantation in Non-ischemic Dilated Cardiomyopathy

This study uses cardiac MRI to guide decisions about whether to implant a defibrillator (ICD) in patients with non-ischemic dilated cardiomyopathy (NIDCM) — a type of heart muscle disease where the heart becomes enlarged and weakened without a history of heart attacks or blocked arteries. Currently, defibrillators are often offered to all patients with severely reduced heart function, but cardiac MRI can reveal which patients have scar tissue (fibrosis) in their heart, which is a key risk factor for dangerous arrhythmias. This study tests whether using MRI to identify fibrosis leads to better-targeted use of defibrillators. The study is for adults aged 18 and older with a diagnosis of idiopathic or familial dilated cardiomyopathy, reduced ejection fraction (35% or below), and evidence of fibrosis on cardiac MRI. You may be eligible if: - You are 18 or older - You have been diagnosed with non-ischemic dilated cardiomyopathy (idiopathic or familial) - Your left ventricular ejection fraction is 35% or below - Your cardiac MRI shows evidence of fibrosis - You have not already had a pacemaker or defibrillator implanted You may NOT be eligible if: - Your heart disease is due to a prior heart attack or coronary artery disease - You have another cardiomyopathy type (e.g., hypertrophic, amyloid, sarcoid) - You have severe kidney disease (creatinine clearance below 30 mL/min) - You have a contraindication to MRI (e.g., pacemaker, claustrophobia, metal implants) - You are pregnant - Your life expectancy is less than 2 years Talk to your doctor to see if this trial is right for you.