Venous inflow stenoses either pulmonary or systemic represents a major complication after Mustard's operation. In order to eliminate such stenoses two modified methods of atrial in version have been developed using no or a minimum of foreign material. The indication for each method is different. Both methods have the incorporation of the remaining atrial septum and of a part of the left atrial wall into the new septum in common. The midportion is completed using a small Dacron patch in cases with fragile atrial tissue (method I) or a flap of the rightatrial wall in cases with normal tissue (method II). The incorporation of growing tissue into the new atrial septum minimizes the risk of secondary stenoses, due to shrinkage or excessive apposition of fibrous pannus.