Arrhythmogenic right ventricular dysplasia is responsible for ventricular tachycardia affecting an apparently healthy heart. It can sometimes lead to sudden death, which may be the presenting symptomatology of the disease. It results from fibro-adipose infiltration of the free wall of the right ventricle, and sometimes of the septum, possibly secondary to myocarditis. The prognosis depends upon the quality of the left ventricle. If it is healthy, the only risk is that of arrhythmia. Treatment using anti-arrhythmic drugs is most often effective and, with proper management, the prognosis is good and the risk of sudden death eliminated. If the left ventricle is abnormal, there is the risk that dysplasia associated with arrhythmia will progress to right then congestive cardiac failure in the context of a dilated idiopathic cardiomyopathy with ventricular tachycardias originating on the right side. Arrhythmogenic right ventricular dysplasia is a notable cause of sudden death in athletes. Routine screening of such individuals is justified, as is that of those with high risk occupations (locomotive and vehicle drivers, etc.).