136: Incidence and Outcomes of Arrhythmias During Pediatric Cardiac Extracorporeal Circulatory Support

Background: Patients on venoarterial extracorporeal membrane oxygenation (VA-ECMO) support may develop arrhythmias, however, data are limited regarding arrhythmia incidence, type, and their effect on outcomes. Methods: We performed a retrospective review of pediatric patients with heart disease requiring VA-ECMO from 1/2020-1/2023. Indications included extracorporeal cardiopulmonary resuscitation (eCPR), cardiogenic shock, hypoxemia, or inability to wean from cardiopulmonary bypass (CPB). Data including demographics, arrhythmia type, and treatment were collected and analyzed using univariable and multivariable analysis. Results: Ninety-one VA-ECMO cannulations in 82 patients were included for study (median age 5.7 months, weight 5.8kg). Diagnoses included congenital heart disease (n=68, 74%), cardiomyopathy (n=18, 19%), and myocarditis (n=3, 3%). Twenty-six patients experienced arrhythmias during 27 (30%) ECMO runs. Arrhythmias included ventricular tachycardia (n=10, 37%), ventricular fibrillation (n=9, 33%), atrial flutter (n=4, 15%), and atrioventricular block (n=4, 15%). Treatment occurred in 26 runs (96%), through a combination of medical therapy (n=15, 57%), defibrillation or cardioversion (n=12, 46%), and/or pacing (n=8, 31%). Arrhythmias on ECMO were associated with increased mortality or need for ventricular assist device (VAD) or transplant (OR 3.03, 95% CI 1.11-8.28), particularly in ventricular arrhythmias (OR 5.37, 95% 1.1-26.0). Ventricular arrhythmias on ECMO were associated with longer ECMO duration (322 vs. 144 hours, p<0.0001) and need for heart transplantation (OR 14.8, 95% CI 3.4-65.4). Conclusion: Patients on VA-ECMO for cardiac indications have a high risk of developing arrhythmias while on mechanical support. Arrhythmias, particularly ventricular arrhythmias, while on ECMO are associated with increased ECMO duration and worse transplant and VAD free survival.