We report a case of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVD) in order to evaluate the course of an under-recognized form of cardiomyopathy with a vast array of clinical manifestations. The patient is a 49-year-old white woman transferred from an outside hospital due to dyspnea and persistent hypoxia. She had a pertinent family history that included a sister who died suddenly in her 30s from unexplained heart failure. Initial work-up for hypoxia was unrevealing. Transthoracic echocardiography revealed isolated right ventricular dysfunction with dilation and multiple trabeculations. Further investigation, including cardiac computed tomography and magnetic resonance imaging, revealed fatty infiltration into the right ventricular wall suggestive of ARVD.