Arrhythmogenic right ventricular cardiomyopathy (ARVC), also known as Arrhythmogenic Cardiomyopathy (AC), is a type of cardiomyopathy where some of the heart muscle is replaced with fatty and fibrous tissue.

This condition primarily affects the ventricles (the lower chambers of the heart) responsible for pumping blood which can lead to arrhythmias, which are also known as abnormal heart rhythms. ARVC mainly affects the right ventricle but often also involves the left ventricle, which is why it is sometimes referred to as arrhythmic cardiomyopathy. Importantly, it does not affect the atria (the upper chambers of the heart).

The cause of ARVC is a defect in the proteins that hold the heart muscle cells together. Due to this defect, the proteins do not form correctly, causing the muscle cells to detach and die. These dead cells are then replaced by scar tissue and fat. The replacement process weakens and stretches the heart muscle, leading to abnormal heart rhythms and reducing the heart's ability to pump blood effectively. 

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.

The Cardiac Society of Australia and New Zealand (CSANZ) has released a Position Statement on the Diagnosis and Management of Arrhythmogenic Right Ventricular Cardiomyopathy (2019 Update). This document is written for clinicians, not patients, but is included here for those who wish to explore more technical information about ARVC.