Statistical Comparison of Echocardiographically Determined Left Ventricular Size Estimated by X-Y Digitizer System between Normotensive and Early Hypertensive Children -The Shimane Heart Study

Recent cardiovascular studies in spontaneous hypertensive rats (SHR) showed that cardiac hypertrophy can he found at the prehypertensive stage. The Shimane Heart Study was carried out since the spring of 1978 for analogous findings in human beings. The population studied included 407 normotensive and 93 early hypertensive children from 9 to 17 years old. We estimated left ventricular posterior wall thickness(LVPWTd) and left ventricular muscle volume (LVMV) on echocardiographic recording paper by X-Y digitizer system which we developed. To make these values independent of age and body size,LVMV/BSA and LVPWTd/LVIDd are calculated. Here BSA and LVIDd are body surface area and left ventricular internal dimension, respectively. Both indices which exhibit left ventricular hypertrophy were significantly larger in early hypertensive children than in normotensive children. Thus, cardiac hypertrophy begins at the early hypertensive stage in human beings as well as in SHR.