CLINICAL INVESTIGATION

ABSTRACT M mode echocardiograms were obtained from 654 healthy subjects, 7 to 22 years of age, whose diastolic blood pressure levels remained in the same height-, race-, and sex-specific decile during two biannual examinations. Echocardiographic measures of heart size, obtained according to the recommendations of the American Society for Echocardiography, were compared across the entire systolic and diastolic blood pressure distributions. Echocardiographic indexes of left heart size varied as a function of both blood pressure levels and body size. Significant positive correlations were present between systolic blood pressure and different measures of left ventricular size. Left ventricular wall thickness in systole correlated with systolic blood pressure (r =.42, p <.0001), and persistence of this relationship was noted after adjustment for body size. Left ventricular wall thickness in diastole correlated with blood pressure before adjustment (r =.31, p <.0001), but the relationship was not significant after adjustment for body size. The ratio of left ventricular thickness to chamber size (systole) correlated with systolic blood pressure levels both before and after adjustment for body size (r =.20 and r =.22, p <.001). Male subjects of both races demonstrated significantly higher adjusted left ventricular mass, left ventricular wall thickness, and left ventricular chamber size. Adjusted left ventricular wall stress was significantly related to both systolic (r =.14) and diastolic blood pressure levels (r =.14, p <.001). Measures of left ventricular wall thickness increased throughout the entire blood pressure distribution, indicating a consistent trend rather than a threshold effect seen only in the highest blood pressure groups. These data demonstrate the early changes in left ventricular geometry across a normal distribution of blood pressure in the young