Risk Factors and Outcomes for Post-operative Arrhythmias Following the Norwood Operation

Despite improvements in survival following staged surgical palliation for single ventricle heart disease, morbidity and mortality remain substantial, particularly during the interstage period following the Norwood operation. Post-operative arrhythmias are common in this population, yet their risk factors and impact on outcomes are not well defined. This study aims to characterize the risk factors and clinical outcomes of arrhythmias following the Norwood operation. We conducted a retrospective cohort study of neonates who underwent the Norwood operation between January 2010 and December 2023 at a quaternary care children's hospital. Clinically significant arrhythmias requiring pharmacologic or electrical intervention were identified. Demographic, intra-, and post-operative variables were collected, along with arrhythmia characteristics. Multivariable logistic regression was used to assess associations with arrhythmias and operative mortality. Among 322 patients, post-operative arrhythmias occurred in 107 (33.2%), with supraventricular tachycardias being most common. Bradyarrhythmias occurred in 3.7% of patients, with 58.3% requiring permanent pacemaker placement. Patients with arrhythmias were younger at surgery and had a higher incidence of acute kidney injury. Arrhythmias were associated with longer ICU (p = 0.003) and hospital stays (p = 0.001). Operative mortality was 18.3%, and while associated with arrhythmias in univariate analysis, only cardiac arrest, higher vasoactive-inotropic scores, and prolonged cardiopulmonary bypass time remained independently associated with mortality. Clinically significant arrhythmias are common following the Norwood operation, particularly supraventricular tachyarrhythmias. Younger age at surgery and post-operative acute kidney injury were associated with arrhythmias. Although arrhythmias were associated with increased morbidity, they were not independent predictors of operative mortality.