ABSTRACT
Echocardiography provides anatomic and pathophysiologic information with reliable quantification of Q p/Q s flow ratio in patients with ventricular septal defect. The aim of this study was to assess the accuracy and reliability of the four different echo color Doppler methods for determining Q p/Q s] ratio comparing the results with the standard oximetry shunt quantification obtained from catheterization laboratory.50 patients [23males, 27 females] were collected from National Heart Institute. Q p/Q s ratio was determined by several methods using Doppler echocardiography and correlated with that obtained from cardiac catheterization. It was found that there was no correlation between method I and cardiac catheterization in detection of Q p/Q s ratio [R = 0.29]. There was a moderate correlation between method II and cardiac catheterization [R = 0.52]. While the correlation decreased in large defects [R = 0.49], there was a well significant correlation in small defects [R = 0.72] and a moderate correlation in moderate defects [R = 0.59]. There was a weak correlation between method III and cardiac catheterization [R = 0.40], while there was no correlation in large defects [R = 0.13], there was a weak correlation in small defects [R = 0.40] and in moderate defects [R = 0.47]. Method IV [Teien] demonstrated the best correlation with catheterization [R = 0.64]. In small defects it was 0.98, moderate defects showed good correlation [R = 0.78] and a less significant correlation was present in large defects. [R = 0.45]. Right to left shunt calculated by Aorta flow + ventricular septal defect flow - Pulmonary Artery flow was found to correlate significantly with catheterization [R = 0.93]. Conclusion and Recoinrnendation. The Doppler Q p/Q s ratio shunt ratio calculated by Teien method correlated the best with oximetry estimates of Q p/Q s ratio and seemed sufficiently accurate for clinical decision making a serial evaluation in infants and children with ventricular septal defect. The new equation [Right - left shunt = Aorta flow + ventricular septal defect flow - Pulmonary Artery flow] is useful in detecting Right to left shunt