The authors report the case of an 18 month old infant with double-outlet right ventricle and subaortic ventricular septal defect with severe subaortic obstruction. Echocardiography showed the subaortic obstruction to be due to severe hypertrophy of the parietal band which grew upwards to the aortic annulus. A peak instantaneous Doppler gradient of 72 mmHg was recorded between the right ventricle and the aorta. The hypertrophy of the band was secondary to pulmonary artery banding performed in the neonatal period at the same time as cure of an isthmic coarctation of the aorta. Surgical exploration confirmed the echocardiographic findings a circular subaortic muscular stenosis related to hypertrophy of the parietal band. Resection of this band liberated the left ventricular outflow tract and made possible a tunnelisation procedure between the left ventricle and the aorta. Postoperative Doppler echocardiography showed the absence of subaortic stenosis.