Doppler echocardiography has been shown to have high sensitivity and specificity for noninvasive detection of the flow disturbance of ventricular septal defect. After surgery for ventricular septal defect, one might expect loss of the ventricular septal defect flow disturbance. We used two-dimensional and pulsed Doppler echocardiography to evaluate 30 children undergoing surgery for ventricular septal defect to determine postoperative Doppler findings and the effect of ventricular septal defect patch material on those findings. Twenty-one patients had Dacron patches and nine pericardial patches. Doppler examinations were performed immediately after surgery and at intervals thereafter. The patches were imaged on two-dimensional echocardiograms and the Doppler method was used to evaluate flow at the patches. Doppler echocardiography was also used to estimate volume flow in the aorta and pulmonary artery to estimate postoperative ratio of pulmonary to systemic flow (Qp/Qs). Immediately after surgery 93% of patients had a flow disturbance detected by Doppler echocardiography in the region of the surgically placed patch. On postoperative day 1, 62% of Dacron-patched defects and 66% of pericardial patched defects showed evidence of residual shunting on Doppler examination. By the third postoperative day, this prevalence fell to 23% and 44%, respectively. By 2 weeks after surgery there was evidence of residual shunting in only two patients. In 26 of 30 early postoperative Qp/Qs estimates were under 1.6/1; all but two of these lost the Doppler-detected flow disturbance by 2 weeks after surgery. In three of 30 Qp/Qs estimates exceeded 1.9/1; two of these three required reoperation.(ABSTRACT TRUNCATED AT 250 WORDS)