The results were as follows;

1) Cardiomegaly (cardiothoracic ratio over 0.5) was seen in 0.19% of each sex and it was higher in middle and high school ages (12~17 years) than primary school ages (6~11 years).

2) Incidences of abnormal electrocardiogram in cardiomegaly were 59.5% in male and 54.7% of female students. Major abnormal electrocardiograms in cardiomegaly were right ventricular hypertrophy (24.8%), left ventricular hypertrophy (11.6%), biventricular hypertrophy(4.8%), complete right bundle branch block (7.7%), incomplete right bundle branch block (8.7%), first degree A-V block (5.8%) and premature beat (4.3%).

3) Left ventficular hypertrophy was seen most frequently in high school ages (15~17 years) and decreased with decreasing age. Right ventricular hypertropy was seen most frequently in primary school ages (9~11 years) and decreased with increasing age. Biventricular hypertrophy was seen most frequently in primary school ages (6~8 years) and decreased with increasing age.

4) Complete and incomplete right vundle branch block were seen commonly in 12~17 years of age and first degree A-V block in 9~11 years of age.