Prognosis of transient atrioventricular conduction disturbances complicating open heart surgery for congenital heart defects

Two patients who had open heart correction of ventricular septal defect and atrioventricular canal in 1956 and 1958, respectively, had recurrences of high degree heart block several years after an episode of transient dysrhythmia in the immediate postperfusion period. As a result of these observations, we chose to review our surgical experience during a period when adequate electrocardiographic observations and follow-up studies were available.

A total of 911 patients less than 15 years of age had had open heart surgical correction of tetralogy of Fallot, ventricular septal defect or atrioventricular canal from 1960 through 1967. Of the 71 surviving patients who had transient complete heart block, second degree heart block, or atrioventricular dissociation immediately after surgery, 59 could be traced, and only 1 patient (with transient atrioventricular dissociation) had return of the dysrhythmia.

During this period, 7 patients had persistent complete heart block after leaving the operating room, and electronic pacing was instituted. Five died within 24 hours after surgery, and the remaining 2 died soon after discharge.

The study revealed that the risk of recurrence of transient postoperative high degree heart block or atrioventricular dissociation is low, and the prognosis for patients with sinus rhythm after such an episode is favorable.