Predictors of rhythm disturbances and subsequent morbidity after the Fontan operation

The electrocardiographic, hemodynamic and surgical data of 30 patients who underwent a Fontan operation between 1977 and 1986 were retrospectively reviewed to identify the incidence and predictors of immediate and late postoperative arrhythmias and associated morbidity in long-term survivors. Of 4 patients who died <1 year after operation (mortality 13%), 1 death was related to an arrhythmia. Three patients were not in sinus rhythm before operation and were excluded from the statistical analysis that examined predictors of arrhythmias. The remaining 23 long-term survivors have been followed 6.3 ± 2.6 years (mean ± standard deviation) since surgery and all remain in New York Heart Association functional class I or II. Ten patients (43%) developed immediate postoperative arrhythmias (≤ 30 days) whereas 11 (48%) had late arrhythmias. With up to 10.7 years of followup, the proportion of patients free from late arrhythmias continues to decline. Arrhythmias included bradyarrhythmias, atrial tachyarrhythmias, the tachy-brady syndrome and supraventricular ectopic activity. Immediate postoperative arrhythmias predicted late arrhythmias (p = 0.022). The preoperative electrocardiogram was the only variable useful in predicting both immediate and late postoperative arrhythmias. A more negative P-wave deflection in lead V₁ (-2.4 ± 0.7 vs -1.4 ± 1.2 mV, p = 0.02) predicted patients with immediate postoperative arrhythmias, whereas both greater P-wave duration and a more negative deflection in this lead predicted late arrhythmias (103 ± 14 vs 83 ± 20 ms, p = 0.01, and -2.5 ± 0.8 vs -1.3 ±1.0 mV, p = 0.005, respectively). Of the 26 surviving patients, 10 (38%) have required ≥1 hospitalizations for control of late arrhythmias. Eight patients are receiving maintenance therapy with multiple antiarrhythmic drugs including amiodarone (1 patient) and 5 have received permanent epicardial pacemakers. Thus, despite excellent functional results after the Fontan operation, postoperative arrhythmias are frequent and cause significant morbidity that will continue to increase with time. Atrial abnormalities on the preoperative electrocardiogram predict those patients who will develop arrhythmias both in the immediate and late postoperative periods. The appearance of an immediate postoperative arrhythmia also predicts the subsequent development of late arrhythmias. Recognition of these predictors may facilitate monitoring and therapy of such patients.