Biatrial tachycardia
Six of 31 regular ATs had reentrant circuits which included both the right and left atria (biatrial tachycardia). Notably, all 6 of these biatrial tachycardias were observed in group B, and no patients in other groups developed biatrial tachycardia. The reentrant circuit consisted of the mitral annulus and right atrial septum in all biatrial tachycardias.
Clinical background, ablation procedures, and ablation outcomes of each patient with biatrial tachycardia are shown in the Supplementary Table. Comparisons of anatomical and electrophysiological properties between patients with and without biatrial AT in group B are shown in Table 4. Patients with biatrial tachycardia had larger anterior and/or septal LVAs, and underwent anterior and/or septal linear ablations.
Ablation targeting breakout points into the left and/or right atria successfully eliminated biatrial tachycardia in 4 of 6 (66.7%) patients. In the remaining 2 patients with failed ablation at left and right atrial breakout points, lateral mitral isthmus linear ablation was performed in 1 patient, but block line could not be achieved. The other patient had conduction disturbance across the septal to anterior region due to an ablation scar, and did not undergo lateral mitral isthmus ablation in consideration of electrical isolation of the left atrial appendage.
Successful AT elimination rate was significantly lower for biatrial tachycardias than for the other ATs (4 of 6 [66.7%] vs. 25 of 25 [100%] ATs, p = 0.010).