Ambulatory blood pressure and left ventricular mass index in hypertensive children.

To determine whether ambulatory blood pressure is more predictive of left ventricular hypertrophy than is casual blood pressure in hypertensive children, echocardiography and ambulatory blood pressure data from 37 untreated hypertensive children were analyzed. Left ventricular mass was calculated using the Devereux equation, left ventricular mass index was calculated as left ventricular mass (in grams)/height(2.7) (in meters), and left ventricular hypertrophy was defined as left ventricular mass index >51 g/m(2.7). Average blood pressure, blood pressure load, and blood pressure index (average blood pressure divided by pediatric ambulatory blood pressure 95th percentile) were calculated. Left ventricular mass index was strongly correlated with 24-hour systolic blood pressure index (r=0.43, P=0.008) and was also correlated with 24-hour systolic blood pressure (r=0.34, P=0.037), 24-hour systolic blood pressure load (r=0.38, P=0.020), wake systolic blood pressure load (r=0.37, P=0.025), sleep systolic blood pressure (r=0.33, P=0.048), and sleep systolic blood pressure load (r=0.38, P=0.021). Left ventricular mass index did not correlate with age, weight, clinic blood pressure, or ambulatory diastolic blood pressure. The overall prevalence of left ventricular hypertrophy was 27%. The prevalence of left ventricular hypertrophy was 47% (8 of 17) in patients with both systolic blood pressure load >50% and 24-hour systolic blood pressure index >1.0, compared with 10% (2 of 20) in patients without both criteria (P=0.015). These data suggest ambulatory blood pressure monitoring may be useful for the clinical assessment of hypertensive children by identifying those at high risk for the presence of end organ injury.