Early rhythm disorders after arterial switch and intraatrial repair in infants with simple transposition of the great arteries.

Between 1986 and 1990 68 infants with transposition of the great arteries (TGA) have been repaired within their first six months of life. From the 51 simple TGA, forming the study group, 20 underwent intraatrial repair according to Mustard and Brom (group I) and 31 received the arterial switch procedure (group II). We compared the observed rhythm disorders after both surgical methods. There were no deaths in group I and 3 deaths in group II. Group I: 7 cases (35%) had early postoperative arrhythmias, 6 patients received transient therapy. There were 3 cases of supraventricular tachycardia (SVT), 2 cases of frequent supraventricular premature beats (SVPB), 1 infant with temporary AV junctional rhythm and 1 with temporary total AV block. Both needed external pacemaker support for maximal two days. Group II: 14 cases (50%) presented rhythm disorders, 13 patients received transient therapy. There were 4 SVT and 3 SVPB. The time of occurrence was between the first and the sixth postoperative day. 2 cases of temporary AV junctional rhythm and 2 infants with transient total AV block needed external pacemaker support for maximal two days. 3 cases with relative sinus bradycardia (less than 130 beats/min) improved clinically with temporary external pacemaker support for several hours. Finally all patients of both groups were in sinus rhythm and after two months all antiarrhythmic drugs could be stopped. There have not been any ventricular arrhythmias in the early postoperative period. During the whole follow up (mean 28 months, range 4-60 m) no arrhythmias reappeared with two (4%) exceptions.