Forty seven patients who underwent anatomical repair of transposition of the great arteries were assessed by Doppler Echocardiography on average 16 months after surgery. Thirty three had transposition alone and 14 had an associated ventricular septal defect. Abnormal left ventricular function was observed in 4 patients (8%) and was associated with a preoperative left to right ventricular systolic pressure ratio less than that of patients with normal left ventricular function (0.76 +/- 0.22 vs 0.90 +/- 0.14 respectively, p = 0.10). Aortic regurgitation was detected in 19 children (40%). It was minimal in 18 cases and mild in the other case, in which a ventricular septal defect has been approached via the original pulmonary valves. Previous pulmonary banding before detransposition was a predisposing factor for postoperative aortic regurgitation. Thirteen patients had pulmonary pressure gradients of over 20 mmHg. The site of obstruction was usually the main pulmonary artery. The 3 cases in which the coronary orifices were closed with two patches instead of one had significant stenosis of the main pulmonary artery. Pulmonary regurgitation was detected in 38 patients (81%); it was minimal in 29 cases, mild in 5 cases and severe in 4 cases. Five patients (11%) had minimal mitral regurgitation and 16 (34%) tricuspid regurgitation. In the 22 cases who had serial echocardiographic evaluation with an average follow-up of 18 months, the postoperative abnormalities were characterised by their stability, with no significant progression of the regurgitant lesions. A reduction in pulmonary pressure gradient was observed in 5 patients and an increase in 1 patient (from 28 to 40 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)