The relationship between blood pressure and left ventricular muscle volume in normal children and adolescents--the Shimane Heart study.

Blood pressure (BP) and left ventricular muscle volume (LVMV) were measured in 408 children and adolescents aged 9-15 years. LVMV was determined by M-mode echocardiography. Lean body weight was approximately calculated using body weight, upper arm circumference and triceps skin fold thickness. Lean-BSA was obtained by substituting lean body weight for body weight in the formula for BSA. Subjects were divided into the high and the low BP percentile groups according to their BP percentile values. LVMVI (= LVMV/BSA) and lean-LVMVI (= LVMV/L-BSA) were compared between the two groups. LVMVI and L-LVMVI were larger in the high BP percentile group than in the low one. Regression lines of LVMV to BSA were also compared between the two groups. Regression lines of the high BP percentile group were located in a higher position than those of the low percentile group. These results suggest that LVMV are larger in the high BP percentile group than in the low percentile group even if their BSAs are equal. We concluded that left ventricular hypertrophy has been already initiated in the pre-hypertensive stage of human beings as observed in spontaneously hypertensive rats.