Electrophysiological abnormalities before and after surgery for atrial septal defect.

The authors evaluated the electrophysiological parameters, atrial-His interval, His-ventricular interval, Wenckebach cycle length, corrected sinus node recovery time (CSNRT), and sinoatrial conduction time (SACT) before and after operation in 28 children with atrial septal defect (ASD). Before operation, electrophysiological abnormalities were detected in 20 (79%) of the 28 patients. Preoperative comparison of the mean value in each parameter between the two age groups showed higher values in all parameters in the older group. In 17 patients who underwent operation, atrial-His interval, Wenckebach cycle length, CSNRT, and atrial effective refractory period (AERP) significantly decreased after operation; preoperatively abnormal Wenckebach cycle length, CSNRT, and AERP values were normalized in many of them. Thus, electrophysiological abnormalities were already present before operation in the ASD children and were severer in the older children, but were improved to some degree following operation.