ARVC may not cause any symptoms in its early stages. However, affected individuals may still be at risk of sudden death, especially during strenuous exercise. When symptoms occur, they most commonly include a sensation of fluttering or pounding in the chest (palpitations), light-headedness, and fainting (syncope). Over time, ARVC can also cause shortness of breath and abnormal swelling in the legs or abdomen. If the myocardium becomes severely damaged in the later stages of the disease, it can lead to heart failure.\n\nArrhythmogenic right ventricular cardiomyopathy (ARVC) is a form of heart disease that usually appears in adulthood. ARVC is a disorder of the myocardium, which is the muscular wall of the heart. This condition causes part of the myocardium to break down over time, increasing the risk of an abnormal heartbeat (arrhythmia) and sudden death.

Short QT syndrome is a cardiac channelopathy associated with a predisposition to atrial fibrillation and sudden cardiac death. Patients have a structurally normal heart, but electrocardiography (ECG) exhibits abbreviated QTc (Bazett's corrected QT) intervals of less than 360 ms (summary by Moreno et al., 2015). For a discussion of genetic heterogeneity of short QT syndrome, see SQT1 (609620).

Familial cold autoinflammatory syndrome-3 is an autosomal dominant immune disorder characterized by the development of cutaneous urticaria, erythema, and pruritus in response to cold exposure. Affected individuals have variable additional immunologic defects, including antibody deficiency, decreased numbers of B cells, defective B cells, increased susceptibility to infection, and increased risk of autoimmune disorders (summary by Ombrello et al., 2012). For a discussion of genetic heterogeneity of FCAS, see FCAS1 (120100).

Brugada syndrome is characterized by cardiac conduction abnormalities (ST segment abnormalities in leads V1-V3 on EKG and a high risk for ventricular arrhythmias) that can result in sudden death. Brugada syndrome presents primarily during adulthood, although age at diagnosis may range from infancy to late adulthood. The mean age of sudden death is approximately 40 years. Clinical presentations may also include sudden infant death syndrome (SIDS; death of a child during the first year of life without an identifiable cause) and sudden unexpected nocturnal death syndrome (SUNDS), a typical presentation in individuals from Southeast Asia. Other conduction defects can include first-degree AV block, intraventricular conduction delay, right bundle branch block, and sick sinus syndrome.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia-14 (ARVD14) is characterized by palpitations, chest pain, and presyncope. Electrocardiography shows epsilon waves, T-wave inversion across anterior leads, premature ventricular contractions, ventricular tachycardia, and left bundle branch block. Dilation of the right ventricle with hypokinesia and aneurysmal changes are seen on echocardiography. Cardiac MRI may show fibrofatty infiltration, which has been confirmed by endocardial biopsy in some patients. Sudden death may occur (Mayosi et al., 2017). For a discussion of genetic heterogeneity of ARVD, see ARVD1 (107970).