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The following is a summary of “Intraoperative Conduction Mapping to Reduce Postoperative Atrioventricular Block in Complex Congenital Heart Disease,” published in the November 2024 issue of Cardiology by O’Leary et al.  

Atrioventricular block requiring pacemaker (AVB/PM) placement complicates 14% to 25% of biventricular repair surgeries for complex congenital heart disease (CHD) and in those with heterotaxy syndrome.  

Researchers conducted a retrospective study to assess whether intraoperative His bundle  (HB) mapping can reduce postoperative AVB/PM implantation in complex CHD repairs.  

They performed HB mapping using a commercially available multielectrode grid catheter in patients with complex CHD undergoing biventricular repair (2019 and 2022); compared with an unmapped cohort, the primary outcome was postoperative AVB/PM placement.  

The results showed that 149 patients underwent HB mapping, compared to 201 controls who did not. The median age of the mapped patients was 1.9 years (Q1-Q3: 0.9–3.9 years). Heterotaxy syndrome was present in 31% (n = 46 of 149), ventricular septal defect in 95% (n = 142 of 149), and prior single ventricle palliation in 68% (n = 89 of 149). The HB was identified in 97% (n = 144 of 149) of cases, the median mapping time was 6 minutes and, no episodes of intraoperative systemic air embolism occurred. Postoperative AVB/PM frequency was reduced in mapped patients with heterotaxy syndrome (2% [n = 1 of 46] vs. 16% [n = 11 of 67]; P=0.026) and in patients without L-malposed great arteries (3% [n = 3 of 88] vs. 11% [n = 15 of 134]; P=0.045).  

They concluded that intraoperative HB mapping safely reduced AVB/PM placement in selected patients undergoing complex CHD repair.  

Source: jacc.org/doi/10.1016/j.jacc.2024.07.054