Myopericarditis in children: elevated troponin I level does not predict outcome.

Myopericarditis is primarily a pericarditic syndrome with some degree of myocardial involvement, as evident by elevated cardiac enzymes. Differentiating myopericarditis from acute coronary syndromes can be challenging and may require coronary angiography or perfusion studies. Data on myopericarditis and its outcome for children are scarce. This study delineates the demography, clinical presentation, and outcomes of myopericarditis for children and evaluates the prognostic value of elevated troponin I. The authors retrospectively reviewed 880 patients younger than 18 years of age who were admitted with diagnoses of chest pain, myocarditis, or pericarditis between 2000 and 2010 at their institution. Myopericarditis was defined as a clinical presentation of pericarditis in the presence of elevated levels of cardiac enzymes. Medical records were reviewed to abstract the demographic data, clinical presentation, evaluation, treatment, and follow-up outcomes. A total of 12 patients (1.4%) with myopericarditis were identified. All the patients were male, 8 (67%) of whom were Caucasian, and their median age was 16 years (range, 11-17 years). Two of the patients (17%) had recently used illicit drugs, and two (17%) had recently smoked cigarettes. At presentation, symptoms included chest pain in 12 patients (100%, 12/12), upper respiratory symptoms in 3 patients (25%, 3/12), and shortness of breath in 3 patients (25%, 3/12). No cardiac murmur or gallop was noted in any patient. Electrocardiographic (ECG) changes included diffuse ST-T changes (5 patients), localized ST-T changes (6 patients), and no ST-T changes (1 patient). All the patients had elevated levels of cardiac enzymes, with a median Troponin I level of 21.4 ng/ml (range, 5.0-134.4 ng/ml) and a median CK-MB level of 50.2 ng/ml (range, 7-135 ng/ml). Echocardiography showed normal left ventricular systolic function in all the patients (median ejection fraction, 61%; range, 56-69%). None had pericardial effusion during the first echocardiographic evaluation. Coronary angiography showed normal coronary arteries in all nine subjects for whom it was performed. Treatment of myopericarditis consisted of ibuprofen, acetaminophen, and/or aspirin. During a median follow-up period of 2 months (range, 2 weeks to 3 years), all the patients were asymptomatic with echocardiography showing normal left ventricular size and function. Myopericarditis was exclusively seen in male adolescents. Despite markedly elevated levels of cardiac enzymes, the clinical evolution of myopericarditis seems benign without any myocardial dysfunction. The inflammatory involvement of the myocardium appears to be self-limited without short-term, overt sequelae. An elevated troponin I level in myopericarditis, unlike acute coronary syndromes, does not seem to carry an adverse prognosis. Further studies are needed to evaluate the long-term prognosis for such patients.