Augmented Wide Area Circumferential Catheter Ablation for Reduction of Atrial Fibrillation Recurrence

Atrial fibrillation (AF) is an abnormal heart rhythm in which the top chambers of the heart beat very fast. AF catheter ablation is a known technique to convert heart rhythm from AF to normal rhythm. The technique sends out electrical energy through a catheter (long thin round solid tubes) to destroy the heart tissues in a focused area where AF is starting. This technique is practiced at many hospitals, including the Heart Institute, and is not experimental. The AWARE study will compare two techniques of AF catheter ablation: 1. Ablation of tissues in wide circular bands around the opening of the pulmonary veins (bring blood back from lungs) in the left upper chamber of the heart. A medicine called adenosine will be given to unmask any incompletely ablated area. Additional ablations will be given if required. This is standard procedure. 2. Same as above but adenosine will not be used. Instead, additional ablation of a second circular band of tissues around the opening of the pulmonary veins will be given. This additional ablation is not standard procedure and is considered experimental. The Investigators are testing if adding more ablation sites will help maintain normal heart rhythm and reduce the rate of return to AF. The study will compare the occurrence of medical events and complications between the two groups. Identical supplies and equipment used in both techniques have been approved by Health Canada. Adenosine is currently approved by Health Canada for the treatment and diagnosis of arrhythmias. 396 participants from study sites across Canada will be randomly assigned "similar to flipping a coin" to treatment group 1 or group 2. After the ablation, participants will have study follow-up at 3, 6 and 12 months. All participant's will be followed for a minimum of 12 months.