Kidney growth in 717 healthy children aged 0–18 months: a longitudinal cohort study
The purpose of this study was to establish normal left ventricular acoustic quantification (AQ) reference values for children from infancy to adolescence and to compare AQ-derived parameters with traditional M-mode and Doppler indices. We studied 150 normal, healthy children aged 2 days to 14 1/2 years. Left ventricular parasternal end diastolic area and left ventricular end diastolic volume calculated by AQ were linearly related to the body surface area to the 1.1 and 1.4 powers. AQ parasternal peak filling rate and atrial fractional area change in the neonatal period were 140% and 142% of the adolescent's values, respectively, and decreased to 110% and 112% by 36 months of age. The duration of the rapid filling phase and the rapid filling contribution, as identified by AQ, was shorter or lower than that measured by the Doppler method. Interobserver variability of AQ parameters ranged from 8.1% for the ejection fraction to 18.2% for the peak filling rate. Manual biplane determinations of volumes were slightly higher than AQ calculations with highly significant correlations (p <0.001). Our data permit the determination of normal ranges of AQ parameters in relation to body surface area or age.