1983 Volume 49 Issue 5 Pages 216-232
Health and clinical examinations of circulatory organs on 1, 400 high-school boys aged 12 to 17 years have been conducted from 1967 to 1981. The followed up data of health examination and clinical tests of cardiovascular disorders were analyzed, and the following conclusions were obtained. 1. Annual Fluctuation of Blood Pressure (observed number: 1, 061) 1) The annual blood pressure fluctuation are shown differently in high and low pressure groups which are divided at 120mmHg of systolic pressure and 70mmHg of diastolic pressure. In the higher blood pressure group, many boys had rather lower pressures at the second year than at the first year, while many boys in the lower blood pressure group had rather higher pressures at the last than at the former. It seems roughly that blood pressures in both groups are gathering to the average of the group. 2) Using both a erage blood pressures and the standard deviations in data for two years, the boys were categorized into three groups according to their blood pressure levels: high blood pressure groups (2.0%), increasing blood pressure group (1.1%), and decreasing blood pressure group (1.3%). 3) The incidence of families with a positive history of hypertension was significantly higher for the high blood pressure group than for the normal blood pressure and low blood pressure groups, thus suggesting that genetic factors give also school-age males some loading of the high blood pressure disposition. 2. Development of Ventricular Conduction Defect in 931 Boys Followed up. 1) After three years' observation, percentage figures for persistent fixation of cardiac ventricle conduction defect were obtained 83.3% for CRBBB, 62.5% for IRBBB, and 43.8% for IRBBB (R>R'), with a clear tendency for the more serious codes to be more fixed. 2) The number of improved cases (39.1%) was greater than that of the deteriorated (19.6%). Such a difference is more evident in cases with a short history of the disease, (improving group: 29.4% and deteriorated group: 8.8%). 3. Time-Course Results of A-V Conduction Defect (observed number: 1, 396) 1) Three years' observation showed that the incidence of I" A-V block was 0.64%, WPW syndrome 0.14%, and P-R shortening 0.07%. 2) The fluctuations of this defect in the course of time showed that the unchangeable type with a constant code was 59.7%, the improving type whose symptoms disappered completely was 22.6%, and the subjects newly developping the condition was 17.7%. 3) The results of Master's two-step test (double) conducted for I" A-V block (observed number: 22) (except for temporary and intermittent cases) showed that the improving type in which the P-R interval tends to be shorter after physical exertion accounted for 77.3%, while the deteriorating type in which this interval tends to be longer after physical exertion for accounted for 9.1%.
