EARLY IDENTIFICATION OF PATIENTS AT RISK FOR SINUS NODE DYSFUNCTION AFTER MUSTARD OPERATION

We studied 60 patients who had survived the Mustard procedure for tran sposition of the great arteries, performed between the ages of 2 days and 24 months (mean 4.51 +/- 3.79). All patients were given a postoper ative 24-hour dynamic electrocardiogram at 15 days, 1 year and 3 years and then every 2 years. Those who were found to have sinus node dysfu nction during follow-up, were given a dynamic electrocardiogram every 3-6 months. The average follow-up period was 38.7 +/- 19.8 months, med ian 36. Sinus node dysfunction was detected during follow-up in 20 pat ients (33.3% of the total), 8 of whom had had a pacemaker inserted. Ri sk factors for late development of sinus node dysfunction were found t o include prolonged cross-clamping of the aorta during surgery (P = 0. 003), especially over 50 minutes (relative risk 3.5:1), and the presen ce of even transient sinus node dysfunction after surgery (P = 0.006). These observations suggests, first, that sinus node dysfunction may d evelop after the Mustard operation as a combined effect of extensive a trial surgery and a long period of myocardial ischemia and, second, th at the presence of the disease immediately after the operation sometim es indicates that it will recur or persist during follow-up.