216-75: Intraoperative arrhythmias in children with congenital heart disease: transient, innocent events?

Abstract

Purpose: Incidences of arrhythmias at intensive care units (ICU) in children after surgery for congenital heart disease (CHD) vary from 15 to 48%. The incidence of arrhythmias in the operating room (OR) in this population has never been reported. In this study, the incidence of intraoperative arrhythmias in children during surgery for CHD will be determined by beat-to-beat rhythm analysis and clinical characteristics of patients with these arrhythmias will be described. Furthermore, we will examine whether intraoperative arrhythmias are associated with development of persistent arrhythmias during follow-up. Methods: Pediatric patients (N = 137, 56% male) undergoing cardiac surgery for various CHD were included. Continuous rhythm registrations (CRR, N = 144) were examined for the occurrence of arrhythmias from the moment the aortic clamps were taken off until the moment the child left the OR and from arrival at the ICU until discharge to the pediatric ICU. Results: Mean age at surgery was 2.5 ± 3.9 years; 7 patients underwent a redo procedure during the study period. In the OR, transient arrhythmias were often observed, including 2nd (45%) and 3rd degree AV-block (AVB, 24%), junctional rhythm (24%) and ectopic atrial rhythm (26%). After cardiopulmonary bypass was stopped, the number of patients with these arrhythmias decreased significantly (p < 0.01). Supraventricular premature beats occurred at a median of 4 per hour (0 – 43) and ventricular premature beats at a median of 3 per hour (0 – 70), both in 106 patients (74%). Atrial fibrillation (N = 1) and ventricular fibrillation (VF, N = 4) occurred infrequently. Mean durations of aortic cross-clamp time and cardiopulmonary bypass were significantly longer in patients with 2nd degree AVB compared to patients without (p = 0.01). Ventricular couplets occurred more frequently in patients undergoing closure of a ventricular septal defect (p < 0.01). At the ICU, junctional rhythm and ectopic atrial rhythm were observed in 8 (6%) and 10 (7%) patients, respectively; 3 and 5 of these patients did not yet have these arrhythmias in the OR. Pre-existent AVB was observed in 3 patients (2%). At the follow-up ECG after 31 months (1 day – 54 months), 87% of patients had sinus rhythm. Fifteen patients (11%) with preoperative sinus rhythm did no longer have sinus rhythm on the late postoperative ECG (p < 0.01); however, 7 of these patients did not have any arrhythmias in the OR or ICU, apart from a low number of atrial/ventricular premature beats. Eight patients died during follow-up at a median age of 1.9 years (0 – 13.4); these patients did not suffer from more arrhythmias in the OR compared to surviving patients (p > 0.11) except for VF (25% versus 2%, p = 0.02). Conclusions: Various intraoperative arrhythmias were frequently observed in children undergoing surgery for CHD but most arrhythmias were transient. However, 11% of patients did no longer have sinus rhythm at latest follow-up. The development of arrhythmias during follow-up appeared not to be related specifically to arrhythmias in the OR or ICU.