Redo AF Sub Study (of the Pure EP 2.0 Main Study)

Cardiac electrophysiologists rely on the display of electrograms when performing EP studies and catheter ablations in patients with arrhythmias. To achieve effective outcomes without complications, it is vital that the recording system enables the recognition of clearly abnormal (scared myocardium) and normal electrical signals. In a redo Atrial Fibrillation (AF) procedure, the patient had previously undergone an AF ablation procedure, but is still having AF episodes, which can be life threatening and have been shown to lead to strokes. Since the original AF procedure involved burning or freezing of myocardial tissue, this is now additional scar tissue and may cause more complex electrograms and intracardiac signals. In this sub study, both the PURE EP™ system and the GE Cardiolab system will be running and recording signals during the entire procedure, with one of the systems displayed on the screen in the procedure room to guide the physician's decision-making. Even numbered subjects will be PURE EP™ guided and odd numbered subjected will be GE CardioLab guided. All other aspects of the procedure will proceed per standard of care. The study will be collect pulmonary vein signals pre and post ablation therapy, along with other non-pulmonary vein signals of interest during a redo ablation procedure. After the physician has completed ablation treatment, matching signals of interest will be extracted from both the PURE EP™ system and the GE Cardiolab recording system as described in the main study. At a later date, a blinded electrophysiologist reviewer will evaluate the signals from both systems with a focus on tissue viability signals and the impact on the procedure. The survey results will then be compared to see the differences in clinical procedure decision-making based on the signal samples.