Rhythm Disturbances in Children With Down Syndrome who Underwent Surgery for Congenital Heart Defects.

Background: Down syndrome is the most common chromosomal abnormality in live-born infants, and approximately 40% to 60% of children with Down syndrome are diagnosed with congenital heart defects. Corrective cardiac surgery can be performed in these individuals with good outcomes. In this study, we aimed to determine the incidence and outcomes of postoperative arrhythmias in patients with Down syndrome who underwent cardiac surgery. Methods: We conducted a retrospective analysis of patients < 18 years of age who were diagnosed with Down syndrome and had cardiac surgery between 2008 and 2023 at two tertiary cardiac centers. Results: Of 328 total patients, the most frequently encountered lesions were complete atrioventricular septal defect (145/328, 44%), ventricular septal defect (85/328, 26%), and partial atrioventricular septal defect (38/328, 11%). The incidence of postoperative arrhythmias was 24% (87 events in 80 patients). Of these arrhythmias, 27/87 (31%) were tachyarrhythmias (junctional ectopic, atrial ectopic, and reentrant paroxysmal supraventricular tachycardia) and 60/87 (69%) were bradyarrhythmias. These included third-degree atrioventricular [AV] block (n = 56) and sinus node dysfunction (n = 4). Twenty-four patients required permanent pacemaker implantation for persistent postoperative AV block (7% of all the study group cohorts). This incidence was higher than the reported incidence of 1% to 3% in the literature and higher than that in infants without Down syndrome who underwent cardiac repair at our two centers (2.4%). Conclusion: Children with Down syndrome who undergo cardiac surgery have a higher incidence of complete AV block requiring permanent pacemaker implantation when compared to children without Down Syndrome. This information is important for the preoperative counseling of families of these patients and postoperative planning.