Discussion

In patients undergoing the Mustard or Senning operation, extensive atrial reconstruction is performed by intra-atrial baffle. This procedure can induce atrial tachyarrhythmias.Reference Gelatt, Hamilton and McCrindle ¹ The mechanism of atrial tachyarrhythmia in adults after intra-atrial baffle procedures varies according to the underlying anatomic defect and the method of surgical repair or palliation.Reference Van Hare, Lesh and Ross ^{2 –} Reference Zrenner, Dong and Schreieck ⁴ However, the focus on arrhythmia was mainly dependent on the acquired surgical scar and chamber enlargement, which results from abnormal atrial pressure and volume loading. In this report, we initially targeted the left-sided pulmonary vein to ablate sustained atrial fibrillation, which was subsequently converted into atrial tachycardia. Atrial tachycardia was subsequently terminated by ablation at the cavo-tricuspid isthmus area of the pulmonary venous atrium side. To access the pulmonary venous atrium, a trans-septal puncture is essential. Compared with standard trans-septal alignment, the needle is directed superiorly and somewhat anteriorly into the septum.Reference Khairy and Van Hare ⁵ In this case, a mapping or an ablation catheter was inserted across a Mustard pericardial patch without complication. The second trans-septal puncture was achieved by directing the needle to a position that was relatively lower and more anterior than the first needle position, thereby making it easier to access the cavo-tricuspid isthmus area. In addition, a double trans-septal puncture helped to determine the confirmation of the bidirectional conduction block of the cavo-tricuspid isthmus by pacing from the low lateral pulmonary venous atrium and coronary sinus ostium. As previously demonstrated,Reference Zrenner, Dong and Schreieck ^{4 –} Reference Wu, Deisenhofer and Ammar ⁶ the most common circuit of intra-atrial re-entry in patients after a Mustard or Senning operation was similar to a typical cavo-tricuspid isthmus-dependent atrial flutter, but the circuit was modified. On the basis of the operative techniques, the cavo-tricuspid isthmus can be exclusively left in the pulmonary venous atrium or is partitioned in both the pulmonary and systemic venous atrium sides. Recently, remote-controlled catheter ablation by magnetic navigation in combination with accurate three-dimensional image integration allowed for the safe and successful elimination of supraventricular tachycardias in patients with intra-atrial baffle anatomy.Reference Ernst, Babu-Narayan and Keegan ⁷ In addition, another study recently demonstrated catheter ablation of atrial fibrillation in this clinical setting. The researchers were able to identify the pulmonary vein trigger and performed four pulmonary vein isolations.Reference Frankel, Shah and Aziz ⁸ It remains to be determined whether only left-sided pulmonary vein isolation is sufficient for eliminating atrial fibrillation. In this case, atrial fibrillation was spontaneously induced twice during the procedure and converted into atrial tachycardia during left-side pulmonary vein isolation. In addition, atrial fibrillation was no longer induced after ablation. Although the left-sided pulmonary vein can be considered as a triggering focus of atrial fibrillation, further recurrence of atrial fibrillation cannot be excluded because the right-sided pulmonary vein was not clearly evaluated.