Inclusion Criteria:  Patient is referred to receive a LAAO procedure for atrial fibrillation, requiring transseptal access and LA catheterization Patients greater than 18 years of age Patient has signed the informed consent form and is willing to participate in the clinical study and data collection  Exclusion Criteria:  Previous left atrial (LA) ablation or LA surgery Active Intracardiac Thrombus Pre-existing pulmonary vein stenosis or PV stent Pre-existing hemidiaphragmatic paralysis Contraindication to anticoagulation or radiocontrast materials Cardiac valve prosthesis Myocardial infarction, PCI / PTCA, or coronary artery stenting during the 3-month period preceding the consent date Cardiac surgery during the three-month interval preceding the consent date Significant congenital heart defect (including atrial septal defects or PV abnormalities but not including PFO) Significant chronic kidney disease (CKD - eGFR <30 µMol/L) Uncontrolled hyperthyroidism Cerebral ischemic event (strokes or TIAs) during the six-month interval preceding the consent date Pregnancy Life expectancy less than one year Currently participating or anticipated to participate in any other clinical trial of a drug, device or biologic that has the potential to interfere with the results of this study Unwilling or unable to comply fully with study procedures and follow-up