157 CARDIAC RHYTHM IN TRANSPOSITION OF THE GREAT ARTERIES PRIOR TO INTRA-ATRIAL SURGICAL CORRECTION

Abstract

Atrial dysrhythmias and conduction abnormalities are well described after intra-atrial corrective procedures for transposition of the great arteries (TGA). To assess the incidence of such dysrhythmias in children with TGA prior to open heart surgery (OHS), 16 consecutive patients (pts) with this diagnosis underwent 24 hr. ECG monitoring (EM). All 16 pts underwent balloon atrial septostomy (BAS); 3 pts required subsequent surgical atrial septectomy. The initial EM's were performed at a median age of 7 days (Range: 2 days-18 mos.) following clinical stabilization. In 8 pts,EM's were performed both in the newborn period and just prior to OHS. All 24 EM's demonstrated exclusively sinus rhythm with no evidence of atrial dysrhythmias or conduction abnormalities; a single pt manifested occasional unifocal ventricular premature contractions on newborn EM. No change was demonstrated on the serial EM's obtained in the newborn period and prior to OHS. Four pts have undergone a Mustard procedure and 2 a Senning procedure. ECG's obtained 2 mos. to 1 yr. post-operatively now demonstrate low amplitude P waves in 3; a single pt with supra-ventricular tachycardia has frequent atrial premature contractions on EM. In this group of pts with TGA evaluated by EM after BAS and atrial septectomy, cardiac rhythm was normal; dysrhythmias seen after intra-atrial correction appear to be exclusively surgically acquired.