Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart muscle disease in which normal myocardium, mainly of the right ventricle (RV), is gradually replaced by fibrous and fatty tissue. This creates a substrate for dangerous ventricular arrhythmias and is one of the recognised causes of sudden cardiac death (SCD) in young people and athletes. It matters in sport because intense exercise can both provoke arrhythmias and accelerate the disease itself, placing it squarely in the sport and exercise medicine (SEM) field. Modern terminology increasingly uses arrhythmogenic cardiomyopathy, since the disease may involve the right ventricle, the left ventricle (LV) or both, but ARVC remains the best recognised phenotype and a common exam term.
For the SEM doctor and the wider musculoskeletal (MSK) team, ARVC is met through screening, an athlete with palpitations or exertional blackout, or a family history of sudden death. The role is to recognise it, investigate sensibly, distinguish it from the athletic heart, refer, and advise on activity.
ARVC is often related to pathogenic variants in the genes encoding desmosomal proteins, the structures binding heart muscle cells together, and is most commonly autosomal dominant, so first-degree relatives are at risk. The genetics are not uniform: penetrance is incomplete, expression varies, rarer recessive forms exist, and a disease-causing variant is found in only a proportion of cases. A variant alone does not establish the diagnosis; it counts alongside clinical, electrocardiographic, imaging, arrhythmic and family features, and is most useful for cascade testing once a familial variant is known.
When desmosomes fail, the stress of repeated contraction damages myocytes, which are replaced by fibrofatty tissue. This begins in the thin-walled right ventricle, producing regional wall motion abnormality, dilatation and, over time, impaired RV function, with the left ventricle involved in a substantial proportion. The scar weakens the pump and, more importantly, disrupts conduction, creating circuits for ventricular tachycardia (VT) and ventricular fibrillation that often arise from the right ventricle and are frequently triggered by exercise. The condition tends to progress from a concealed phase to overt structural and electrical disease.
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