Detection and evaluation of asymptomatic myocarditis in schoolchildren - Report of four cases

Study objective: Data on the prevalence of myocarditis in children are limi ted, Autopsy studies have shown that myocarditis is often undiagnosed. We a ttempted to investigate the clinical features of asymptomatic myocarditis i n four schoolchildren detected during a mass ECG screening in schoolchildre n, Design and setting: To evaluate asymptomatic myocarditis, we clinically exa mined 12 schoolchildren who were referred to Shiga University of Medical Sc ience Hospital, Otsu, Japan, because of abnormal ST or T waves detected dur ing ECG screening. None of the 12 children had experienced any episodes sug gesting cardiac disease or Kawasaki disease, Cardiac function and myocardia l viability were assessed by two-dimensional echocardiography (2-DE), thall ium-201 (Tl-201) myocardial scintigraphy, and cardiac catheterization. Endo myocardial biopsy specimens were examined histologically. Patients: Endomyocardial biopsy specimens revealed histologic evidence of m yocarditis in 4 of the 12 children with abnormal ST or T waves. Results: Abnormal tracer perfusion was observed on Tl-201 myocardial scinti grams in these four children, but the results of coronary arteriography wer e normal, 2-DE showed left ventricular hypokinesis in one child and left ve ntricular enlargement in one of the four children with histologic evidence of myocarditis. A second endomyocardial biopsy specimen was obtained in two of four children, showing persistent myocarditis in one child, Conclusions: This type of screening program and indepth evaluation using 2- DE and Tl-201 myocardial scintigraphy appear to be helpful in identifying c hildren with myocarditis. The present histologic investigations suggested t hat even asymptomatic myocarditis might result in persistent heart damage.