Case Illustration of the Natural History of Left Dominant Arrhythmogenic Cardiomyopathy.

Arrhythmogenic left ventricular cardiomyopathy is an increasingly recognized cause of recurrent myocarditis, a mimicker of acute coronary syndrome, and an important cause of malignant ventricular arrythmias and heart failure. Desmoplakin is a protein that is critical to maintaining the structural integrity of the myocardium. Disruption of desmoplakin leads to fibrofatty infiltration of the myocardium which leads to congestive heart failure, cardiac arrhythmias, and sudden cardiac death. However, desmoplakin cardiomyopathy is often misdiagnosed, resulting in significant morbidity and mortality. We report 2 contrasting cases illustrating the natural history-hot and cold phases-of arrhythmogenic left ventricular cardiomyopathy. The first case demonstrates a common phenotypic presentation of desmoplakin cardiomyopathy manifested as recurrent myocarditis and myocardial injury representing the hot phase. The second case is an undulating course of chronic systolic heart failure and ventricular arrhythmias representing the cold phase. Arrhythmogenic cardiomyopathy manifests as a spectrum of disease processes that involve the right, left, or both ventricles. Mutations in the desmoplakin gene are often associated with a left dominant ventricular cardiomyopathy. Diagnosis remains difficult as the condition has no signature clinical presentation, and imaging findings are variable.