Arrhythmogenic right ventricular cardiomyopathy/dysplasia is characterized by the progressive replacement of myocardium by fatty or fibrofatty tissue. Presenting symptoms are generally related to ventricular arrhythmias, including sudden cardiac death. Heart failure due to right ventricular and sometimes left ventricular dysfunction is uncommon in the early stages of the disease, but is known to occur in advanced cases. This case report describes identical adolescent twins with presenting symptoms related predominantly to right heart failure.