A reliable fossa ovalis impedance mapping for safer transseptal puncture: A new vision beyond voltage.

INTRODUCTION: Transseptal puncture (TSP) is widely used in clinical practice but is negatively affected by a nonneglectable rate of complications and X-ray exposure. To address these problems, we investigated whether or not impedance mapping could correctly identify fossa ovalis (FO) and safely guide TSP. METHODS AND RESULTS: Electroanatomic mapping was performed with CARTO 3 system version 7 and a ThermoCool® SmartTouch® mapping catheter was employed. In each patient, an impedance map and a bipolar voltage map of the whole interatrial septum were collected, acquiring at least 150 points with a contact force ≥2 g and using the pattern matching filter. Thirty-five patients were enrolled. A low impedance area was clearly identified in 34 of them. In 30 patients (88%), the FO was located in the low impedance area. The map was obtained in sinus rhythm in 17 cases (50%); in 15 of these (88%), the TSP site, the patent foramen ovale, or the FO tenting area fell inside the low impedance area. The same numbers were observed when mapping during atrial fibrillation. CONCLUSION: To the best of our knowledge, this is the first study that provides the reliability and reproducibility of impedance mapping in identifying FO, an affordable and feasible tool that could be potentially introduced into clinical practice.

Zero-fluoroscopy atrial fibrillation ablation in the presence of a patent foramen ovale: a multicentre experience.

INTRODUCTION: Atrial fibrillation ablation has historically been guided by fluoroscopy, with the related enhanced risk deriving from radiation. Fluoroscopy exposure may be confined to guide the transseptal puncture. Small sample size study presented a new methodology to perform a totally fluoroless atrial fibrillation ablation in the case of a patent foramen ovale (PFO). We evaluated this methodology in a large sample size of patients and a multicentre experience. METHODS AND RESULTS: Two hundred and fifty paroxysmal atrial fibrillation patients referred for first atrial fibrillation ablation with a CARTO3 electroanatomic mapping system were enrolled. In 58 out of 250 patients, a PFO allowed crossing of the interatrial septum, and a completely fluoroless ablation was performed applying the new method (Group A). In the remaining patients, a standard transseptal puncture was performed (Group B). Pulmonary vein isolation was achieved in all patients with comparable procedural and clinical outcomes at short- and long-term follow-up. CONCLUSION: The presence of a PFO may allow a completely fluoroless well tolerated and effective atrial fibrillation ablation. Probing the fossa ovalis looking for the PFO during the procedure is desirable, as it is not time-consuming and can potentially be done in every patient undergoing atrial fibrillation ablation.