Acute Myocarditis With Very High Troponin but No Ventricular Dysfunction

A 13-year-old African boy without significant past medical history was admitted to our hospital because of syncope. He had a cold with flu-like symptoms and chest pain since the day before. Initial electrocardiography showed a first-degree atrioventricular block. While waiting in the emergency room, he suffered a second syncopal episode. Repeated electrocardiography showed a complete atrioventricular block and an escape rhythm with a heart rate of 20 beats/min (Figure 1), for which temporary pacing was performed. Echocardiography was normal with a left ventricular ejection function of 70%. He received only supportive care. High-sensitive cardiac troponin T was elevated to 1785 ng/L (normal value <14 ng/L) at time of admission, peaked at 2210 ng/L the next day, then trended down to 56 ng/L after 6 days (Figure 2). Cardiac magnetic resonance imaging showed areas of mid-myocardial delayed enhancement with sparing of the subendocardial tissue, compatible with myocardial inflammation. Blood samples revealed seroconversion for antibodies to parvovirus B19. The conduction disorders disappeared on the second day after admission and the patient made a full recovery without any recurring cardiovascular symptoms or findings after discharge.