Arrhythmogenic right ventricular cardiomyopathy, or ARVC, is a type of cardiomyopathy that is characterised by the replacement of heart muscle with fatty and fibrous tissue. It is a type of cardiomyopathy that affects the ventricles (the lower pumping chambers) of the heart and causes arrhythmias (abnormal heart rhythms). It affects the right ventricle, and often also affects the left ventricle. For this reason it is sometimes called arrhythmic cardiomyopathy (as the main symptoms are arrhythmias). It doesn't affect the atria (upper chambers) of the heart.

It is caused by a defect in the proteins that join the cells of the heart muscle together. This means that the proteins do not develop properly and cannot keep the muscle cells together. When this happens the muscle cells detach and die and are replaced with fibrous scar tissue and fat deposits. This affects the structure of the heart muscle, and it becomes thin and stretched, causing arrhythmias and preventing the heart from pumping blood properly.

ARVC can be caused by changes in genes that encode for proteins that are involved in the structure and function of the heart muscle. ARVC is inherited in an autosomal dominant manner.

ARVC can be caused by variants in genes that encode for proteins that are involved in the structure and function of the heart muscle. These proteins include desmosomal proteins, which are involved in cell-to-cell adhesion in the heart muscle.

Mutations in the PKP2 gene are the most common cause of familial ARVC. Other genes that have been linked to ARVC include DSG2, DSP, and JUP. 

Genetic testing is not always necessary for diagnosing ARVC. The condition can also be diagnosed based on clinical symptoms, such as arrhythmias or abnormal electrocardiogram (ECG) results.

Some cases may be due to other factors, such as viral infections or inflammation.