Estimation of outflow tract pressure gradients by continuous wave Doppler in children.

Continuous wave Doppler echocardiography was used to estimate pressure gradients in 27 children with right or left ventricular outflow tract obstruction. The pressure gradients predicted by Doppler were compared to peak-to-peak and instantaneous gradients measured at cardiac catheterization. When the Doppler study was performed the pressure gradient obtained at catheterization was not known to the examiner. A correlation coefficient of 0.76 was found for the comparison between the Doppler predicted gradient and the peak-to-peak gradient and 0.78 for the comparison with the instantaneous pressure gradient. Clinically significant obstructions could be reliably separated from insignificant obstructions by the Doppler technique.