Myocardial Inflammation Reveals a Genetic Desmosomal Cardiomyopathy in an Athlete

BACKGROUND: Myocarditis frequently overlaps with phases of myocardial inflammation in inherited cardiomyopathies. CASE SUMMARY: A 32-year-old female athlete was referred because of bradycardia, troponin elevation, and high burden of premature ventricular contractions. Cardiac magnetic resonance imaging demonstrated features of both potential myocardial inflammation and arrhythmogenic right ventricular cardiomyopathy (ARVC). Despite clinical stability, troponin I levels rose to a peak level of 304,065 ng/L. Endomyocardial biopsy showed evidence of acute lymphocytic myocarditis, and immunosuppressive therapy was initiated. Genetic testing revealed a likely pathogenic variant in the PKP2 gene, which encodes plakophilin 2. A diagnosis of ARVC was made. DISCUSSION: This case highlights the overlap between apparent myocarditis in an athlete and "hot-phase" ARVC. TAKE-HOME MESSAGE: Genetic testing may have an important role in athletes presenting with myocarditis, because high-intensity exercise may trigger rapid disease progression and increases the risk for ventricular arrhythmias in patients with inherited cardiomyopathies, especially in ARVC.