A Pictorial Review of the 2020 Padua Criteria in Diagnosing Arrhythmogenic Cardiomyopathy with Insights from Native T1 Mapping

Arrhythmogenic cardiomyopathy (ACM) is a heritable myocardial disorder characterized by progressive fibrofatty replacement, typically involving the right and/or left ventricles. The 2020 Padua Criteria offer an updated, multiparametric diagnostic framework that addresses the limitations of the 2010 Task Force Criteria. Cardiac magnetic resonance (CMR), particularly native T1 mapping, has emerged as a pivotal modality for myocardial tissue characterization in ACM. This prospective study evaluated four patients with clinically suspected ACM and 12 age-matched healthy controls. All participants underwent comprehensive CMR at 3.0 Tesla, including cine imaging, late gadolinium enhancement (LGE), and native/postcontrast T1 mapping. The Padua Criteria were applied for diagnostic classification and phenotypic characterization. Quantitative T1 mapping was employed to assess myocardial fibrosis. Application of the Padua Criteria yielded diagnoses of right-dominant ACM (n = 1), biventricular ACM (n = 2), and a borderline case (n = 1). Native T1 values were significantly elevated in the right ventricular free wall among ACM patients compared with controls (mean 1462.25 vs. 1245.51 ms, p < 0.0001). Notably, native T1 mapping identified diffuse myocardial abnormalities in cases lacking LGE. The Padua Criteria facilitates accurate phenotypic classification of ACM. Native T1 mapping enhances diagnostic sensitivity, particularly in early or subtle disease, and represents a promising noninvasive biomarker of myocardial fibrosis. Further validation in larger cohorts is warranted.