[Arrhythmia after atrial correction of transposition of the great vessels. Holter recording study of 123 surgically treated patients].

Sinus node dysfunction after intra-atrial repair of transposition of the great arteries by a Mustard or Senning procedure is well known. We undertook this study to evaluate the frequency, the nature, the severity and evolution of these dysrhythmias by performing Holter monitoring in 123 children followed up over 5 years; 302 Holter recordings were reviewed. The patients were divided into 3 groups of increasing severity: I = no sinus node dysfunction, II = moderate sinus node dysfunction, III = severe sinus node dysfunction with bradycardia of less than 30/min and/or pauses of over 2000 ms. The association of atrial hyperexcitability was classified in 3 subgroups: A = no extrasystoles, B = at least 4 extrasystoles per 24 hours, C = atrial tachycardia (focal tachycardia or flutter) after the first six postoperative months. There were only 15% of normal recordings (IA) and the majority of children (58%) were classified in the intermediary groups (IB, IIA and IIB). Sinus node dysfunction tended to become more severe with time in nearly 30% of the 69 cases followed up sequentially. The bradycardia tended to become more severe and associated with episodes of atrial tachycardia: the frequency of type B and C increased to 30% in Group I, to 68% in Group II and to 91% in Group III. The attacks were severe, especially in patients with a mediocre postoperative haemodynamic result. This explains the global mortality of 3%, the morbidity of 15% and the pacemaker implantation rate of 12%.(ABSTRACT TRUNCATED AT 250 WORDS)