Arrhythmogenic left ventricular cardiomyopathy
Domenico Corrado, Cristina Basso
Abstract
### Learning objectives Arrhythmogenic cardiomyopathy (ACM) is a genetic heart muscle disease characterised by substitution of the ventricular myocardium by fibrofatty tissue.1 The disease was originally termed ‘arrhythmogenic right ventricular (dysplasia/) cardiomyopathy’ (ARVC) to define a condition which distinctively affected the right ventricle (RV) and predisposed to potentially fatal ventricular arrhythmias, particularly in young individuals and athletes.2–4 New insights arising from postmortem investigations, genotype–phenotype correlation studies and myocardial tissue characterisation by contrast-enhanced cardiac magnetic resonance (CMR) led to increased awareness that the disease often also involves the left ventricle (LV).5–11 The current designation of ‘arrhythmogenic cardiomyopathy’ better reflects the evolving concept of a heart muscle disease affecting both ventricles, with some phenotypic variants characterised by a parallel or predominant involvement of the LV. The adjective ‘arrhythmogenic’ refers to the distinctive clinical propensity of the disease to cause ventricular arrhythmias in relation to the fibrofatty scar tissue, which is a recognised arrhythmogenic myocardial substrate. Patients with a long-standing disease may develop RV or biventricular dysfunction.4 This definition of ACM substantially differs from that provided by the 2019 expert consensus statement endorsed by the Heart Rhythm Society (HRS),12 that is, a non-specific entity which encompasses a heterogeneous group of heart muscle disorders, including ‘systemic’ diseases such as sarcoidosis and amyloidosis; ‘inflammatory’ diseases such as myocarditis; ‘infectious’ diseases such as Chagas disease; and ‘genetic’ diseases such as desmosomal and non-desmosomal forms; and ‘ion …