Risk factors for postoperative arrhythmia in patients with physiologic univentricular hearts undergoing Fontan procedure

Objective: Advanced age, dilated right atrium, increased preoperative pulmonary artery pressure, increased right atrial pressure, technique of operation, and poor ventricular function were reported to be risk factors for postoperative arrhythmia. Aim of this study is to determine the risk factor for postoperative arrhythmia after Fontan operation with regard to ventricle dominancy and hemodynamic parameters. Methods: In this retrospective study, the data of the patients including age, weight, dominant ventricle, type of cardiac anomaly, previous operations, duration of cardiopulmonary bypass (CPB), duration of aortic clamping, cardiac rhythm, pulmonary artery pressure, the Nakata Index, systemic atrioventricular (AV) valve insufficiency were obtained from the hospital records, the echocardiographic files, and cardiac catheterization records. Patients were assigned to dominant left ventricle or dominant right ventricle groups. Statistical analysis was performed using the Mann-Whitney U test. Results: Arrhythmia was observed in 21 (52.5%) patients in the postoperative period. No postoperative arrhythmia was observed in patients with a right atrial pressure of 5 mmHg, whereas postoperative arrhythmias were observed in patients with a right atrial pressure of ≥5 mmHg (p 0.05). When the effects of preoperative and postoperative pulmonary artery pressures on postoperative arrhythmia were evaluated, post- operative arrhythmia was determined in only 2 (12.5%) of 8 patients with a preoperative mean pulmonary artery pressure of ≤9 mmHg, where- as postoperative arrhythmia was observed in 19 (59.3%) of 32 patients with a preoperative pulmonary artery pressure of ≥10 mmHg. A preoperative mean pulmonary artery pressure of 10 mmHg increased the risk of postoperative arrhythmia (p 0.02). Postoperative arrhythmia was determined in 8 (53%) of 15 patients with a dominant right ventricle, and in 13 (52%) of 25 patients with a dominant left ventricle (p 0.05). Conclusion: While a preoperative mean pulmonary artery pressure of 10 mmHg and a preoperative right atrial pressure of 5 mmHg were the risk factors for postoperative arrhythmia in patients undergoing Fontan procedure, the right or left ventricular dominance was not a risk factor.