SINCE approximately 90% of the infants with untreated transposition of the great vessels die before they reach the age of 6 months, palliation should be undertaken early in most cases.1 The basic concept of atrial septectomy to facilitate intracardiac mixing described by Blalock and Hanlon in 19502 remains the standard method of palliation, although numerous modifications in technique have been developed because of the discouragingly high operative mortality.
Balloon dilatation of the foramen ovale with a cardiac catheter has recently lowered the risk of palliative atrial septotomy to less than 20%.3 However, in many cases the torn edges of the foramen ovale approximate and become thickened from scarring again within several weeks. Subsequent redilatation of the foramen ovale with a balloon catheter is more hazardous and may again be followed by stenosis of the septal defect.
This report describes an operative technique of atrial septectomy without