Pediatric/Adult Congenital Heart Disease -> Pediatric Cardiology D-PO04 - Poster Session IV (ID 15) Poster

D-PO04-032 - Prevalence Of Post-operative Heart Block Following Biventricular Repair Of Unbalanced Atrioventricular Canal Defects (ID 421)


Background: Patients with unbalanced complete atrioventricular canal defects (uCAVC) have historically been surgically palliated to a single ventricle physiology. In an effort to avoid the morbidities associated with single ventricle palliation, our center has adopted a biventricular repair (BiV) strategy for patients with uCAVC. Due to the posterior displacement of the AV node in CAVC defects and the high prevalence of heterotaxy in uCAVC, the location of the AV node is unpredictable intraoperatively, raising concern for postoperative heart block.
Objective: To quantify the prevalence of postoperative complete AV block (AVB) requiring permanent pacemaker (PM) implantation following BiV repair of uCAVC defects.
Methods: Single center retrospective cohort study of pediatric patients undergoing repair of uCAVC between 2001-2019. The primary outcome was PM implantation for AVB following BiV repair. Patients with uCAVC were included if: (1) preoperative left or right ventricular end diastolic volume Z-scores were less than -2.0 on cardiac magnetic resonance imaging or echocardiography; or (2) patients had previously undergone any stage of single ventricle palliation.
Results: 105 patients underwent BiV repair for uCAVC with a median age of 2.7 (range 0.23-16.0) years and weight of 11.8 (4.3-47.9) kg. 100 (95%) of patients had a prior palliative surgical procedure. Right ventricular dominance was present in 75 (71%) of cases. Heterotaxy was present in 53 (50%) and L-looped ventricles in 21 (20%) patients. PM implantation for AVB occurred in 12 (11%) patients. AVB was not associated with age or weight at time of BiV repair, ventricular dominance, ventricular looping, heterotaxy, or prior single ventricle palliation. Those who experienced AVB trended towards longer median intensive care unit length of stays (14 vs 11 days, p=0.07).
Conclusion: Patients undergoing BiV repair for uCAVC are at an elevated risk of AVB requiring permanent pacing. No clear patient or procedural-level risk factors for this complication were identified. Catheter-based or intraoperative mapping of the His bundle is now being added to our management scheme in an effort to reduce conduction system injury, given the long-term morbidities associated with ventricular pacing.