Our group has previously reported a large prospective experience with the use of intraoperative echocardiography with Doppler color-flow imaging (IE-DCFI) during the repair of congenital heart defects. We have now performed IE-DCFI in 621 patients and have observed a major change in the impact of this technology, which has stabilized during our most recent experience (the last 207 patients). To evaluate the surgical learning curve with IE-DCFI, we divided patients into three groups: group 1, patients 1 through 207; group 2, patients 208 through 414; and group 3, patients 415 through 621. There were no major differences between groups with respect to age or disease entities. The average time needed to perform an IE-DCFI examination decreased from 3.75 +/- 1.77 minutes in group 1 to 3.35 +/- 1.52 minutes in group 2 and has remained stable. The number of patients requiring revisions in the operating room (based on IE-DCFI findings) decreased from 17 (8%) in group 1 to 7 (3%) in group 2 to 5 (2%) in group 3. Furthermore, revisions were 100% successful in correcting the problem in groups 2 and 3, whereas 18% of group 1 patients left the operating room with persistent residual defects by IE-DCFI. Surgeons can acquire the ability to interpret the results of IE-DCFI themselves and use it to enhance their operative repair of congenital heart defects, but this requires an experience of at least 200 cases.(ABSTRACT TRUNCATED AT 250 WORDS)