Concurrent Arrhythmogenic Right Ventricular Cardiomyopathy and Hypertrophic Cardiomyopathy: A Rare Phenotypic Overlap

Background: Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) and Hypertrophic Cardiomyopathy (HCM) are distinct inherited cardiac disorders that represent leading causes of sudden cardiac death, particularly in young adults. While both conditions display autosomal dominant inheritance patterns, they typically involve different genetic mutations and pathophysiological mechanisms. Case report: We present a rare case of a 45-year-old male with ventricular tachycardia who demonstrated concurrent phenotypic features of both ARVC and HCM on comprehensive cardiac evaluation. Electrocardiography showed epsilon waves characteristic of ARVC, while cardiac magnetic resonance imaging (CMR) revealed right ventricular dilatation consistent with ARVC alongside mid-ventricular hypertrophic obstructive cardiomyopathy (HOCM). This unusual phenotypic overlap highlights the importance of comprehensive multimodality cardiac imaging and raises intriguing questions about potential genetic and molecular intersections between these cardiomyopathies. Conclusion: This case highlights the importance of comprehensive multimodality cardiac imaging in identifying complex structural abnormalities and raises questions about potential genetic and molecular intersections between ARVC and HCM. Our case also adds to the extremely limited literature documenting the co-occurrence of these conditions and underscores the value of CMR in identifying complex structural cardiac abnormalities. Management of patients with this rare phenotypic overlap presents unique challenges, requiring careful consideration of risk stratification and medical therapy. Further research may provide valuable insights into the pathophysiology and optimal management strategies for patients with overlapping cardiomyopathic phenotypes.