ECHOCARDIOGRAPHIC APPEARANCES AND SURGICA L FINDINGS IN SECONDARY SUBAORTIC OBSTRUCTION AFTER CORRECTION OF DOUBLE-OUTLET RIGHT VENTRICLE

The authors report echocardiographic appearances of subaortic obstruct ion secondary to correction of double outlet right ventricle in 8 chil dren reoperated between January 1994 and June 1996. The initial repair of the double outlet right ventricule was performed before 3 months o f age in 6 cases. Forms with subaortic ventricular septal defects (4 c ases) and those with ventricular septal defects not connected to the g reat arteries (2 cases) were treated by tunneling between the left ven tricule and the aorta, and forms with subpulmonary ventricular septal defects (2 cases) by tunneling between the left ventricle and pulmonar y artery and detransposition. Reoperation for subaortic obstruction wa s 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 : stenosi s of the tunneling patch (n = 2), subaortic fibrous ring (n = 3), musc ular septal hypertrophy (n = 1), antero-lateral muscular hypertrophy ( n = 1), relies 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 deter mined in 6 of the 8 cases. The mechanism of obstruction by stenosis of the tunneling patch was only detected in 1 of the Z cases. This study shows 2D echocardiography to be the investigation of choice for follo w-up of operated double outlet right ventricle for the diagnosis of se condary subaortic obstruction.