Introduction: Transseptal puncture (TP) for left-sided catheter ablation procedures is routinely performed under fluoroscopic or transesophageal echocardiographic guidance. To decrease radiation exposure, increase safety as well as patient comfort, alternative imaging techniques are desirable. Intracardiac echocardiography (ICE) would comply with these requisites, however is still a matter of expense. This study thought to assess the feasibility and safety of a right atrial (RA) 3D electroanatomic-map (EAM)-guided transseptal puncture.

Methods: In 106 patients undergoing pulmonary vein isolation for paroxysmal or persistent atrial fibrillation, electroanatomic RA mapping was performed to identify the fossa ovalis (FO) using the protrusion technique. The radiofrequency (RF) transseptal needle was visualized in the EAM and navigated to the desired potential FO-TP site. Thereafter, the electrophysiologist was unblinded to transesophageal echocardiography (TOE) and the potential FO-TP site was reassessed regarding its convenience and safety. After TP, the exact TP site was documented using a 17-segment FO module.

Results: Reliable identification of the FO was feasible in 104 patients (98%). In those patients, 114 3D EAM-guided TP attempts were performed of which 96 attempts (84%) demonstrated a good position and 18 attempts (16%) demonstrated an adequate position after TOE unblinding. An unclear or even dangerous position was not seen. A successful 3D EAM-guided TP was performed in 110 attempts (97%). Three attempts (3%) with adequate position after TOE unblinding were aborted in order to seek a more convenient TP site. No TP-related complications occurred. Ninety-eight of 3D EAM-guided TP sites (85,1%) were in the central portion or in the inner loop of the FO (Figure 1).

Conclusion: Right atrial 3D electroanatomic-map-guided transseptal puncture is easy, convenient and safe. It may assist to further decrease radiation exposure as well as the need for TOE during left-sided catheter ablation procedures.