Dysrhythmias after repair of atrial septal defect.

To determine the incidence of dysrhythmias following repair of isolated secundum atrial septal defect, postoperative electrocardiograms were reviewed in 292 patients. The PR interval was shortened by the 7th postoperative day (p <.05) as compared to the preoperative PR interval. Sinus rhythm only was observed in 228/292 (78%). Nine patients (3%) had a preoperative dysrhythmia. A postoperative dysrhythmia was observed in 64/292 (22%). Twenty-two (7.5%) had symptomatic postoperative dysrhythmias. A tachydysrhythmia was found in 16/64 (25%) of these. The latest occurrence of symptomatic dysrhythmia was 17 years after surgery. Currently, 7/292 (2.4%) of the patients reviewed have a pacemaker. Five of 292 (1.7%) had Holt-Oram syndrome. All five patients with Holt-Oram syndrome had postoperative dysrhythmias; two patients were symptomatic. Serious dysrhythmias may present years after repair of an atrial septal defect. Patients with Holt-Oram syndrome are at greater risk for development of postoperative dysrhythmias.