Cardiac magnetic resonance imaging as a prognostic tool in patients with nonischemic cardiomyopathy.

Technical advancements have enabled cardiac magnetic resonance (CMR) imaging to provide a noninvasive assessment of cardiomyopathy. Cardiac magnetic resonance imaging acts as the reference standard for quantifying left and right ventricular function. It also assesses the etiology of cardiomyopathy by demonstrating the presence and size of myocardial scar and by detecting myocardial inflammation and interstitial infiltration. Cardiomyopathy can result in early mortality and arrhythmic risk, and CMR imaging aids in risk stratification among this group of patients. Left ventricular ejection fraction predicts which patients will benefit most from implantable cardioverter-defibrillators (ICDs), but this is not a perfect marker of arrhythmic risk. The etiology of cardiomyopathy, as assessed with CMR imaging, adds further prognostic information with infiltrative cardiomyopathies, resulting in higher mortality than idiopathic cardiomyopathies. Among patients with nonischemic cardiomyopathy (NICM), the degree of fibrosis as determined by the CMR imaging sequence of late gadolinium enhancement (LGE) imaging offers further prognostic information. Late gadolinium enhancement imaging in patients with NICM portends an approximately 3- to 8-fold greater risk of death or hospitalization than NICM without LGE imaging. Further research is needed to determine if the presence of LGE will be helpful in predicting which patients may benefit from ICD implantation.