ARRHYTHMIAS AND THROMBOEMBOLIC COMPLICATIONS AFTER THE EXTRACARDIAC FONTAN OPERATION

Background: Late morbidity and mortality after the Fontan operation ar e largely due to atrial arrhythmias, ventricular failure, and thrombus formation. The extracardiac Fontan procedure avoids extensive atrial manipulation and suture lines, theoretically minimizing the impetus fo r these events. We examined our experience with the extracardiac Fonta n operation with particular attention to thromboembolism and arrhythmi as, Methods and results: We retrospectively reviewed the medical and s urgical records of all 16 patients who underwent an extracardiac Fonta n operation between July 1993 and May 1996. Fifteen patients (94%) wer e in sinus rhythm before the operation. In the immediate postoperative period, seven (44%) had arrhythmias consisting of accelerated junctio nal rhythm and ectopic atrial rhythm. No associated hemodynamic compro mise and no early deaths occurred. Patients were followed up for 3 to 34 months after the Fontan operation. Arrhythmias were detected in eig ht patients (50%) on surface electrocardiograms, and seven (44%) showe d evidence of sinus node dysfunction on 24-hour Holter monitor studies . Thrombi were found in three patients (19%). All patients were asympt omatic, with no evidence of conduit obstruction by echocardiogram. Con clusions: The incidence of hemodynamically significant tachyarrhythmia s appears to be reduced after the extracardiac Fontan operation. A sig nificant percentage of patients have evidence of sinus node dysfunctio n, suggesting the presence of other surgical or nonsurgical factors re sponsible for this finding. Our incidence of thrombotic events is simi lar to previous reports with other Fontan modifications. It appears to be a reasonable option to maintain these patients on anticoagulation indefinitely.