Distinct CMR Phenotype in Alcoholic Cardiomyopathy: Greater Myocardial Fibrosis and Right Ventricular Dysfunction Compared with Idiopathic Dilated Cardiomyopathy

Background/Objectives: Alcoholic cardiomyopathy (ACM) is a major preventable cause of non-ischemic dilated cardiomyopathy (DCM), yet its specific cardiac magnetic resonance (CMR) remains incompletely defined. We aimed to characterize the CMR features of ACM, focusing on late gadolinium enhancement (LGE) subpatterns and biventricular function and to compare them with idiopathic DCM. Methods: In total, 148 consecutive patients (ACM n = 20, idiopathic DCM n = 128) referred for CMR at a single center were retrospectively analyzed. Sequential logistic regression adjusted for age, sex, left ventricular ejection fraction (LVEF), and right ventricular ejection fraction (RVEF) was used to identify independent association with LGE presence. Results: LVEF did not differ between groups (32.5% vs. 35.0%, p = 0.293). ACM patients showed significantly worse RVEF (40.5% vs. 52.0%, p = 0.010) and larger indexed right ventricle (RV) volumes. Any LGE was present in 70% vs. 40% (p = 0.015); when the non-specific RV insertion point pattern (non-RV-IP) was excluded, non-RV-IP LGE was 45% vs. 22.7% (p = 0.051), with a specific midwall linear pattern (25% vs. 8%, p = 0.033). ACM was independently associated with LGE across all models with an adjusted odds ratio (OR) of 3.06 [95% CI 1.05–8.95], p = 0.041, and RV dysfunction (RVEF < 45%) (OR 4.79 [95% CI 1.60–14.32], p = 0.005). No differences in major adverse cardiovascular events (MACEs) were observed at 24 months (log-rank p = 0.697). Conclusions: ACM has a distinct CMR phenotype characterized by midwall linear LGE fibrosis and more severe RV involvement, independent of left ventricle (LV) systolic function. These exploratory findings suggest that CMR may provide clinically relevant phenotypic information in ACM beyond LVEF, warranting confirmation in prospective studies.