BACKGROUND: Anti-melanoma differentiation-associated gene 5 dermatomyositis (anti-MDA5 Ab+ DM) is characterized by amyopathic DM with interstitial lung disease. Its impact on the right ventricle remains unclear. We aim to evaluate RV involvement in anti-MDA5 Ab+ DM patients using cardiovascular magnetic resonance (CMR). METHODS: This single-center, prospective cohort study included 43 anti-MDA5 Ab+ DM patients (24 males, mean age = 44.7 ± 11.1 years) and 30 age- and gender-matched healthy controls (18 males, mean age = 44.8 ± 10.4 years). All patients underwent CMR before treatment. RV functional parameters, including ejection fraction (RVEF), end-diastolic/end-systolic remodeling index (RVEDRI/RVESRI), and right ventricular long-axis strain (RV-LAS), and RV and LV T1 and T2 mapping were analyzed. Differences between the two groups were evaluated, and correlations with clinical data were explored. RESULTS: Anti-MDA5 Ab+ DM patients exhibited a significant decrease in RVEF (45.7 ± 5.9% vs. 52.7 ± 6.6%, CONCLUSION: RV subclinical dysfunction is common in patients with anti-MDA5 Ab+ DM. RV parameters on CMR such as RV-LAS and RVESRI serve as valuable imaging markers for early detection and risk stratification. These findings underscore the importance of routine cardiac evaluation in anti-MDA5 Ab+ DM.