Aneurysm of the membranous ventricular septum. Surgical consideration and experience in 29 cases.

Twnety-nine cases of aneurysm of the membranous septum in association with various cardiac abnormalities are described. These aneurysms are more common than has been previously thought (10% of the total associated anomalies managed surgically). The patients' ages ranged from 3 months to 28 years. All of the 29 patients were divided into three groups. Group I consisted of 15 patients with ventricular septal defect (VSD), 5 of whom had associated artrial septal defect (ASD). Group II consisted of 5 patients with VSD and pulmonic obstruction, and Group III comprised 9 patients with transposition of the great arteries (TGA). Complete correction was performed in all the patients, and the aneurysm was imbricated in the suture line of the VSD in all cases but one. There was only one hospital death, the result of subpulmonic obstruction. This occurred in the first patient of this series, who had aneurysm of the membranous septum in TGA and VSD and in whom the aneurysm was not suspected preoperatively and was overlooked at surgery. There were no late deaths. In 5 patients a small residual VSD and in 3 patients a small recurrent aneurysm were found in a postoperative study. When these accompanying aneurysms are encountered during surgery or are previously diagnosed, resection or imbrication of the sac should be accomplished in order to prevent further enlargement or postoperative arrhythmias and, especially in TGA, to avoid fatal subpulmonic obstruction as occurred in our only death. According to the present data, in the presence of an aneurysm, even a small VSD should be closed by a patch and the aneurysm should perhaps be excised.