This study will evaluate the efficacy of 2D forward-looking and 3D Intracardiac Echocardiography (ICE) to guide septal punctures during Atrial Fibrillation ablation procedures.

This study is part of a multiphase study. Phase 1 involves 10 patients at a single centre. Phase 2 will be done a multi centre study.

Inclusion Criteria:

• Patient is at least 18 years old.
• Patient is undergoing an atrial fibrillation ablation procedure.
• Patient has a transesophageal echocardiogram (TEE) within the 48 hours prior to ablation procedure to rule out left atrial thrombus.
• Patient provides informed, written consent for participation in the study.

Exclusion Criteria:

• Patients in whom placement of an ICE catheter in the right atrium for adequate atrial visualization is not technically feasible (as evaluated and determined by the physician performing the procedure).
• Patients in whom transseptal puncture is relatively contraindicated.
• Patients in whom left atrial clot or dense spontaneous contrast is identified on TEE, which would increase thromboembolic risk.
• Women of child bearing potential, in whom pregnancy cannot be excluded.
• Patients unable to grant informed, written consent for participation in the study.