Abstract
Arrhythmogenic cardiomyopathies (ACM) are rare inherited cardiac disorders, with an incidence below 1% in adults and an undetermined prevalence in pediatric populations. Formerly recognized primarily as arrhythmogenic right ventricular cardiomyopathy (ARVC), affecting exclusively the right ventricle (RV), recent diagnostic advancements have shed light on the involvement of the myocardium in ACM, revealing fibrous infiltration in both ventricles. In 2023, the European Society of Cardiology introduced updated phenotypic classifications of cardiomyopathy, highlighting the coexistence of multiple types within families and the potential transition from one cardiomyopathy to another. We present a case series comprising four pediatric cases of ARVC with diverse presentations and outcomes. Subsequent evaluations unveiled both left ventricle (LV) and RV dysfunction, culminating in a diagnosis of ARVC based on the 2020 diagnostic criteria. Additionally, genetic testing uncovered mutations in genes associated with cardiomyopathies. Cardiac magnetic resonance imaging (MRI) corroborated the biventricular involvement, aligning with a diagnosis of ACM per the 2020 Padua criteria. In conclusion, recent updates in diagnostic criteria have refined the classification of ACM, underscoring the importance of cardiac MRI and morphological features for precise diagnosis. Genetic testing has identified novel mutations linked to cardiomyopathy, emphasizing the significance of personalized treatment strategies and genetic counselling for affected individuals and their families.