The purpose of this clinical investigation is to evaluate how safe a less invasive cardiac surgery using the AtriCure Bipolar System in conjunction with a catheter ablation procedure performed approximately 1-10 days after, in treating atrial fibrillation, and how effective is this staged procedure. The AtriCure Bipolar System will be used to perform the less invasive cardiac surgery and a standard electrophysiology catheter, currently available, will be used to perform the catheter ablation procedure. This surgical procedure is considered less invasive because it is done through tiny surgical punctures on the sides of the chest near the ribs instead of one large surgical incision of the breast bone to completely open the chest and access the heart, and it also avoids the need for the heart-lung bypass machine.