PREDICTORS OF EARLY-ONSET AND LATE-ONSET SUPRAVENTRICULAR TACHYARRHYTHMIAS AFTER FONTAN OPERATION

Background-The objectives of our study were to determine the frequency of supraventricular tachyarrhythmias (SVTAs) among modifications of t he Fontan operation and identify risk factors for developing SVTA. Met hods and Results-The population consisted of all patients who had any modification of the Fontan operation at the Mayo Clinic between 1985 a nd 1993. Clinically significant SVTAs were those requiring initiation or change of antiarrhythmic treatment, and they were divided into earl y SVTAs (<30 days after the operation) and late SVTAs (greater than or equal to 30 days after the operation). Clinical histories were review ed, and health status questionnaires were sent. Four hundred ninety-ni ne patients had various modifications of the Fontan operation. Frequen cy of early SVTA was 15%, Risk factors identified by multivariate anal ysis for early SVTA were AV valve regurgitation, abnormal AV valve, an d preoperative SVTA. Frequency of late SVTA was 6% by 1 year, 12% by 3 years, and 17% by 5 years. Risk factors for late SVTA were age at ope ration (<3 or greater than or equal to 10 years) and systemic AV valve replacement. By univariate and multivariate analysis, the type of Fon tan operation was not a significant risk factor for late SVTA when all 6 modifications were considered. However, when we analyzed the freque ncy of late SVTA for the 2 recently used modifications, we found a low er frequency of late SVTA in patients with atriopulmonary connection w ith lateral tunnel compared with those with total cavopulmonary connec tion. Conclusions-Postoperative SVTA continues to be a significant pro blem. Risk factors for SVTA are AV valve regurgitation, abnormal AV va lve, preoperative SVTA, and age at operation. Frequency of SVTA does n ot appear to be related to type of Fontan procedure except for slightl y lower frequency in patients with atriopulmonary connection with late ral tunnel compared with those with total cavopulmonary connection.