Determinants of myocarditis in young adults — a single centre 3-year experience

Abstract

Introduction. Myocarditis is a challenging diagnosis due to the heterogeneity of clinical presentations. This inflammatory myocardial disease should be diagnosed based on established clinical, laboratory and imaging criteria.

Material and methods. We studied consecutive patients aged 18–40 years admitted to an emergency department (ED) with the diagnosis of an acute coronary syndrome (ACS) between January 01, 2011 and December 31, 2013. Demographic, clinical and laboratory data were analysed. The patients were diagnosed with myocarditis based on the history of a respiratory or gastrointestinal tract infection, clinical symptoms of reduced exercise tolerance, chest pain, arrhythmias or new onset symptoms of heart failure, with abnormal electrocardiographic and/or echocardiographic findings and elevated markers of myocardial necrosis. All subjects underwent coronary angiography to exclude or confirm an ACS.

Results. Patients with myocarditis were younger (median age 30.5 years, interquartile range [IQR] 20.5–32) compared to ACS patients (median age 39 years, IQR 35–39.5; (p = 0.001). All young adults with myocarditis had a history of infection within 4 weeks and it was the strongest determinant of myocarditis (odds ratio [OR] 113.7, 95% confidence interval [CI] 5.64–2289.7; p < 0.001). Compared to ACS patients, those with myocarditis were more likely to report a history of fever (OR 17.22; 95% CI 0.9–330.5; p = 0.06) and have an elevated white blood cell count (median 9.95, IQR 8.3–11.95 vs. 8.2, IQR 6.4–10.32; p = 0.07), elevated high-sensitivity C-reactive protein level (OR 29.3; 95% CI 1.14–748.6; p = 0.04), higher left ventricular ejection fraction (median 60, IQR 60–65 vs. 55, IQR 50–55; p = 0.001),and elevated creatine kinase activity (OR 7.94; 95% CI 1.41–44.8; p = 0.02). Dyslipidaemia was less frequent in young adults with myocarditis (OR 0.03; 95% CI 0.003–0.3; p = 0.002).

Conclusions. Infection-related parameters are key determinants of myocarditis in young adults with chest pain. These easily accessible clinical and laboratory parameters should guide further clinical decision-making in ED.