A pediatric case of hypertrophic cardiomyopathy with mid-ventricular obstruction incidentally detected by electrocardiography.

A 13-year-old girl was admitted to our hospital because mitral P wave and ST depression in leads II, III, aVF, and V3-6 were incidentally detected on electrocardiography at a school health examination. Although she had noted no cardiac symptoms during club volley ball games, the treadmill exercise test induced chest discomfort in the absence of obvious electrocardiographic changes. B-type natriuretic peptide was elevated at 685 pg/ml. Echocardiography revealed left mid-ventricular hypertrophy and obstruction, sparing of the apical ventricle at end-systole, and severe left atrial dilatation. Continuous-wave Doppler echocardiography clarified a peak pressure gradient of about 40 mmHg between the apical and basal sites of the left ventricle. Swan-Ganz catheterization suggested elevated atrial pressure and left ventricular end-diastolic pressure. Left ventriculography showed an "hourglass" appearance. Endomyocardial biopsy revealed cardiac muscle cell disarray. We diagnosed a rare pediatric case of hypertrophic cardiomyopathy with mid-ventricular obstruction. This case reconfirms that electrocardiography during school health examinations is a very important screening tool for the detection of asymptomatic or mild symptomatic cardiac diseases.