Long-term Outcome in Patients With Pacemakers Following the Fontan Operation Steven B. Fishberger, MD, Gil Wernovsky, MD, Thomas L. Gentles, MB, ChB, Walter J. Gamble, MD, Kimberlee Gauvreau, ScD, Janice Burnett, John E. Mayer, Jr., MD, and Edward P. Walsh, MD T he Fontan operation has been performed for a va- riety of complex congenital heart lesions when the cardiac anatomy precludes a 2-ventricle repair.ls3 Earlier reports suggest that preoperative criteria for a successful Fontan operation included the presence of sinus rhythm with normal atrioventricular (AV) conduction.4 However, many patients who are can- didates for a Fontan operation, particularly those with L-looped ventricles ( AV discordance) develop complete heart block, resulting in placement of a pacemaker.5 Furthermore, frequent sequelae after a Fontan operation include atria1 tachyarrhythmias and sinus node dysfunction.6-s Pacemaker implantation is often beneficial as primary or adjunctive ther- apy. 9,‘o With recent modifications, “,‘* there has been increased interest in performing the Fontan operation in patients who were previously considered to be un- suitable candidates. Although many patients who un- dergo a Fontan operation also have a permanent pacemaker, little is known about the long-term re- sults in this population. Previous reports have been limited to case reports or small series of patients.‘3-‘” The purpose of this study was to report on the char- acteristics of a large group of patients with pace- makers who have undergone a Fontan procedure to evaluate their long-term outcome. . . . Between April 1973 and July 1991, 500 patients underwent a Fontan operation at Children’s Hospital, Boston. A retrospective chart review, and review of all available anatomic and hemodynamic data, elec- trocardiograms, and Holter monitor recordings were performed. As part of a comprehensive cross-sec- tional review conducted between September 1992 through June 1994, surviving patients’ cardiologists were requested to provide a recent clinical evalua- tion, electrocardiogram, and Holter monitor record- ing. A questionnaire inquiring about the functional state was sent to each surviving patient. Patients de- termined to have had a permanent pacemaker either before or after a Fontan operation form the basis of this report. Hemodynamic and electrophysiologic re- sults are the subject of separate reports. Age-specific functional data were obtained from the questionnaire or from the referring physician if a questionnaire was not available, and a New York Heart Association From the Departments of Cardiolo y ond Cardiac Surgery, Children’s Hospital, and the Departments o Pedlatrlcs and Surgery, Harvard 9 ” MedIcal School. Dr. Walsh’s address IS: Department of Cardiology, Children’s Hospital, 300 ion wood Avenue, Boston, Massachusetts 02 1 15. Manuscript receive c? July 2 1, 1995; revised manuscript re ceived and accepted November 17, 1995. classification of functional status was derived by consensus of 2 of the authors. Univariate analyses of pacing modalities with re- spect to survival and New York Heart Association class following Fontan surgery were performed us- ing the Kaplan-Meier method. Differences between groups were evaluated by a log rank test. A p value co.05 was considered statistically significant. Of the 500 patients who underwent a Fontan op- eration, pacemakers were implanted in 46 (9.2.%), 9 before Fontan, 4 at the time of Fontan surgery, and 33 after Fontan. Anatomic diagnoses included 16 with L- looped ventricles, 13 with tricuspid atresia. 7 with a single left ventricle, 2 with heterotaxy syndrome, 2 with hypoplastic left heart syndrome, and 6 witlh a va- riety of other complex cardiac lesions. Patients under- went a Fontan operation at a mean age of 9.6 t- 7.6 years. An extracardiac conduit was performed in 9 pa- tients, a direct atriopulmonary connection in 23, and a total cavopulmonary anastomosis in 14. The mean fol- low-up interval was 6.0 2 4.4 years (range 0 to 14.5) after Fontan, and 3.2 i 2.7 years (range 0 to 12.2) after pacemaker implantation, with a mean age at fol- low up of 15.6 2 9.2 years. Indications for pacemaker implantation include sinus node dysfunction (n = 7)) AV block (n = 22)) atria1 flutter with (n = 13) and without (n = 2) co- existing sinus node dysfunction, or sinus node dys- function and AV block (n = 2). All 9 pacemakers placed before Fontan surgery were for AV block. The mean time to pacemaker implantation after Fon- can surgery in patients with sinus node dysfunction, atria1 flutter, or both, was 5.4 ? 4.3 years (range 0 to 12.7). Pacing modes included 9 with single-chamber ventricular pacing (VVI), 19 with dual-chamber pacing (DDD), and 18 with atria1 pacing ( AAI), 8 of which have antitachycardia pacing capability. Since 1984, most patients (90% ) aged >2 years with AV block received dual-chamber pacing. Among the 9 patients who received a VVI pacemaker, 3 were aged 52 years at the time of pacemaker implanta- tion, and 4 had their pacemaker placed before 1984. Whereas none of patients with DDD pacing, had an extracardiac conduit, the distribution with respect to a direct atriopulmonary connection and a total ca- vopulmonary anastomosis was similar between those with VVI and DDD pacing. Preoperative hemody- namics measured at cardiac catheterization and age at Fontan surgery did not differ among the various pacing modes. One patient with congenital A.V block initially received a VVI pacemaker as a newborn and BRIEF REPORTS 887