Clinically it is important to detect slight changes in the size and contour of the heart and to try to differentiate between normal and slightly enlarged hearts. Enlargement of the left ventricle occurs frequently with rheumatic heart disease. The present study was undertaken to evaluate one of the quantitative roentgenologic methods used to indicate the size of the left ventricle in children.
Wilson,1 by determining the degree of rotation necessary to separate the left lower border of the heart (left ventricle) from the vertebral column in fluoroscopic examination in the left anterior oblique position, introduced an index of cardiac size and termed it the angle of clearance. For 97 per cent of 119 normal children ranging in age from 5 to 15 years the angle of clearance was less than 55 degrees; it was between 40 and 45 degrees for 49 per cent, between 45 and 55 degrees for