Cardiac Magnetic Resonance Imaging and Arrhythmic Risk Stratification in Cardiomyopathies.

Cardiac magnetic resonance imaging (CMRI) has become an indispensable tool in evaluating arrhythmic risk and guiding therapeutic decisions in patients with non-ischemic cardiomyopathies (NICMs), including dilated (DCM), hypertrophic (HCM), and arrhythmogenic cardiomyopathies (ACM). Both European and American guidelines have given an additive and different value of late gadolinium enhancement (LGE) in specific morpho-functional (hypertrophic, dilated, and arrhythmogenic) phenotypes. In particular, LGE plays a different weight in relation to different cardiomyopathies. In dilated cardiomyopathy, LGE is able to predict arrhythmic risk in relationship to the presence and localization (septal and/or ring like LGE). On the contrary, in HCM, LGE is related to increased risk of cardiac death according to the extent (LGE >15%), while in ACM, it has a greater role in the presence of fat infiltration associated with LGE. In this review, we aim to identify predictors of sudden cardiac death related to myocardial structural features seen in CMRI in cardiomyopathies, going beyond the sole assessment of left ventricular function and ejection fraction.