Arrhythmogenic Right Ventricular Cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart muscle disease in which myocardium, mainly of the right ventricle (RV), is replaced by fibrous and fatty tissue, causing ventricular arrhythmias.

It is a recognised cause 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. The left ventricle (LV) is often involved too; some clinicians use the umbrella term arrhythmogenic cardiomyopathy, but the 2023 European Society of Cardiology (ESC) guidelines keep the name ARVC.

The sport and exercise medicine (SEM) clinician meets ARVC through screening, an athlete with palpitations or exertional blackout, or a family history of sudden death. The role is to recognise it, tell it apart from the athletic heart, refer, and advise on activity.

ARVC is often caused by variants in genes encoding desmosomal proteins, the structures that bind heart muscle cells together, and is most commonly autosomal dominant, so first-degree relatives are at risk. Penetrance is incomplete, rarer recessive forms exist, and a variant is found in only a proportion of cases. A variant alone does not make the diagnosis; it counts alongside clinical, ECG, imaging and family features, and is most useful for cascade testing.

When desmosomes fail, the stress of repeated contraction damages myocytes, which are replaced by fibrofatty tissue. This begins in the thin-walled RV, causing regional wall motion abnormality, dilatation and, over time, impaired function. The LV is involved in a substantial proportion.

The scar disrupts conduction, creating circuits for ventricular tachycardia (VT) and ventricular fibrillation that often arise from the RV and are frequently triggered by exercise. The disease tends to progress from a concealed phase to overt structural and electrical disease.