Case summary:
A 21-year-old athletic male with a family history of unknown ventricular arrhythmias, presented with near syncope, chest pain and exertional palpitations. He had an initial work-up that was grossly unremarkable including, electrocardiography (ECG), echocardiography and CMR imaging. Six months later, he presented again with recurrent symptoms during exercise and his ECG demonstrating a new epsilon wave. He had markedly elevated cardiac biomarkers, (troponin I >100 ng/dl, normal value < 0.04 ng/dl). A subsequent coronary angiogram was performed, which was normal. Holter monitoring further showed subsequent episodes of ventricular tachycardia with a right bundle branch morphology. An endomyocardial biopsy was performed, which was negative. A follow-up CMR demonstrated the new development and prominentleft ventricular epicardial scar in the lateral wall.
The patient underwent familial genetic testing, which confirmed the presence of an isolated JUP gene mutation and showed multiple genes consistent with ARVC in his mother. Thus, he manifested a partial transmission of only one abnormal gene for ARVC and exhibited a markedly different expression in his disease without evidence of typical right-sided heart pathology. A third CMR study was performed, which showed partial improvement in myocardial fibrosis after exercise cessation.