Additional Left Atrial Appendage Isolation During Balloon Ablation for Persistent or Long-standing Persistent Atrial Fibrillation

This study is testing whether adding isolation of the left atrial appendage (a small pouch in the heart) during a balloon-based heart ablation procedure improves outcomes for patients with persistent or long-standing atrial fibrillation (an irregular heart rhythm). **You may be eligible if...** - You are between 18 and 80 years old - You have persistent or long-standing persistent atrial fibrillation (AF that has lasted more than 7 days, or more than 12 months) - Your doctor has recommended ablation treatment for your atrial fibrillation - Your left atrial appendage is of appropriate size and your atrium is not overly enlarged **You may NOT be eligible if...** - You have paroxysmal atrial fibrillation (comes and goes on its own) - Your AF has been continuous for more than 4 years - You have had a prior ablation procedure or MAZE surgery for AF - You have had a prior left atrial appendage closure procedure or surgical removal - You have a blood clot in your atrium - Your left atrium is very large (greater than 60 mm) Talk to your doctor to see if this trial is right for you.