Nomograms for mitral inflow Doppler and tissue Doppler velocities in Caucasian children

BACKGROUND: Pediatric echocardiographic nomograms for systolic/diastolic functional indices are limited by small sample size and inconsistent methodologies. Our aim was to establish pediatric nomograms for mitral valve (MV) pulsed wave Doppler (PWD) and tissue Doppler imaging (TDI) velocities. METHODS: We performed PWD/TDI measurements of MV velocities and generated models testing for linear/logarithmic/exponential/square root relationships. Heteroscedasticity was accounted for by White test or Breusch-Pagan test. Age, weight, height, heart rate (HR), and body surface area (BSA) were used as independent variables in different analyses to predict the mean values of each measurement. RESULTS: In all, 904 Caucasian Italian healthy children (age 0 days-17 years; 45.5% females; BSA 0.12-2.12m2) were prospectively studied. No individual variable provided equations with an acceptable coefficient of determination (R2) and even the inclusion of multiple variables in the model resulted in only a partial amelioration of the R2. Higher R2 were obtained for PWD-E deceleration time (0.53), septal (Se') and lateral (Le') MV-TDI e' velocity (Se': 0.54; Le': 0.55). Variability was higher at lower age and BSA. In older children patterns were more reproducible; however, the exclusion of neonates did not substantially improve the final models. The low R2 hampered building of z-scores and calculation of estimated percentiles. Thus normative data have been presented as observed percentile according to age for all measurements. CONCLUSIONS: We report normal ranges for PWD and TDI mitral velocities derived from a large population of Caucasian children. Variability of diastolic patterns especially at lower ages needs to be taken into account.