Impact of transseptal puncture location on the fossa ovalis on first-pass pulmonary vein isolation

Background: Recently, radiofrequency catheter ablation (RFCA) has become an important treatment strategy for atrial fibrillation (AF). During this procedure, achieving first-pass pulmonary vein (PV) isolation — PV isolation in which no residual conduction gap remains following initial circumferential lesion is created around the PV — has proven to lead better results in terms of AF recurrence. Although various risk factors for the creation of residual conduction gap have been proposed, the relationship between the transseptal puncture location on fossa ovalis and first-pass PV isolation success rate has not been clarified. Therefore, we investigate the relationship through this investigation. Methods: Overall, 102 consecutive patients who had undergone their first RFCA for AF were included. These patients were divided based on the transseptal puncture location (infero-anterior, infero-posterior, supero-anterior, and supero-posterior), which was confirmed by imaging of three-dimensional structure of the anatomical fossa ovalis creating intracardiac echocardiography. The relationship between transseptal puncture location and the first-pass PV isolation success rate was analyzed. Results: Among all 102 patients, the number of transseptal puncture locations located in infero-anterior, infero-posterior, supero-anterior, and supero-posterior were 26, 61, 6, and 9 respectively. Among these, first-pass PV isolation success rate in the infero-posterior group exhibited the highest 79% (48/61 patients) compared to that in other locations [infero-anterior 61% (16/26 patients), supero-anterior 33% (2/6 patients), and supero-posterior 44% (4/9 patients); P=0.02]. Regarding ablation parameters, although the ablation index was not significantly different between each group (infero-anterior 401.6±7.6, infero-posterior 401.9±5.2, supero-anterior 397.5±4.7, and supero-posterior 398.6±5.3, P = 0.176). The P-vector, which represents insufficient catheter contact, was significantly observed lower frequency in the infero-posterior group (8.6%; P < 0.01) than in the other groups. Conclusion: The transseptal puncture location in PV isolation is an important factor to achieve first-pass PV isolation, and it might affect AF recurrence.