[Secondary subaortic obstruction after correction of double outlet right ventricle. Echocardiographic aspects and surgical findings].

The authors report echocardiographic appearances of subaortic obstruction secondary to correction of double outlet right ventricle in 8 children reoperated between January 1994 and June 1996. The initial repair of the double outlet right ventricule was performed before 3 months of age in 6 cases. Forms with subaortic ventricular septal defects (4 cases) and those with ventricular septal defects not connected to the great arteries (2 cases) were treated by tunneling between the left ventricule and the aorta, and forms with subpulmonary ventricular septal defects (2 cases) by tunneling between the left ventricle and pulmonary artery and detransposition. Reoperation for subaortic obstruction was performed after 18 to 33 months. The instantaneous maximal gradient measured by Doppler echocardiography was high, ranging from 60 to 145 mmHg. The causes of the secondary subaortic obstruction were stenosis of the tunneling patch (n = 2), subaortic fibrous ring (n = 3), muscular septal hypertrophy (n = 1), antero-lateral muscular hypertrophy (n = 1), relics of tricuspid tissue inserted on the infundibular septum (n = 1). Subaortic obstruction was diagnosed in the echocardiographic subcostal views in all cases; the nature of the obstruction was determined in 6 of the 8 cases. The mechanism of obstruction by stenosis of the tunneling patch was only detected in 1 of the 2 cases. This study show, 2D echocardiography to be the investigation of choice for follow-up of operated double outlet right ventricle for the diagnosis of secondary subaortic obstruction.