Atrial Fibrillation Patients Treated With Catheter Ablation

This study is following patients with atrial fibrillation (an irregular heartbeat) who are having a catheter ablation procedure — a minimally invasive technique that uses heat or cold energy to destroy the small areas of heart tissue causing the arrhythmia. The study aims to understand outcomes after this treatment. **You may be eligible if...** - You are between 18 and 80 years old - You have been diagnosed with non-valvular atrial fibrillation (either paroxysmal or persistent) - Your heart specialist has recommended bilateral pulmonary vein isolation (a specific ablation technique) - The left atrium of your heart is not too enlarged (less than 50mm diameter on ultrasound) - You have agreed to proceed with ablation treatment **You may NOT be eligible if...** - A blood clot has been found inside your heart - You have an overactive thyroid that has not been treated - You have previously had a catheter ablation procedure for atrial fibrillation Talk to your doctor to see if this trial is right for you.