Methods: A total of 670 pediatric patients (355 males, 315 females; median age: 4 months; range, 1 day to 18 years) who underwent cardiac surgery due to congenital heart defects between December 2018 and November 2019 were included. The rate of postoperative arrhythmias, diagnosis, potential risk factors, and management strategies were evaluated. Multivariate regression analysis was used to identify significant factors of development of postoperative arrhythmias.

Results: Tachyarrhythmia was detected in 54 patients (8.1%), and the most common tachyarrhythmia was junctional ectopic tachycardia. Medical treatment was required in 25/38 (66%) of junctional ectopic tachycardia patients. Amiodarone was initiated in 18, dexmedetomidine in five, and flecainide + amiodarone in two of the patients. Different degrees of atrioventricular block were observed in 30 patients (4.5%). In 12 patients, permanent pacemakers were implanted during hospitalization. Age at the time of surgery under one-year-old, high inotropic scores, prolonged operation time, and high Aristotele"s scores were independent risk factors associated with early postoperative arrhythmia (p<0.05). The most common operations associated with early postoperative arrhythmia were left ventricular outflow tract, (6/20, 30%), complete atrioventricular septal defect (13/53, 24%), and tetralogy of Fallot (20/134, 14%) surgeries.

Conclusion: Cardiac arrhythmias are common in the early period after congenital heart surgery in children. The diagnosis and frequency of arrhythmias may vary according to different surgical procedures.