Atrial fibrillation is an irregular heart rhythm which requires long term anticoagulation to prevent risk of stroke and long term poor outcomes. At the same time one have heart surgery, a small additional procedure can be done to treat atrial fibrillation. Surgeons have a choice of six different devices that he or she can use to treat your atrial fibrillation. It is not known at this point which device is best at treating you, as each device seems to have the same success rate at curing atrial fibrillation. One of the six devices will be selected randomly by card pulled out at the time of enrollment. It is therefore the purpose of this study to compare the devices to each other and to follow up after surgery to determine if any one device is best. This information will be valuable to surgeons and to patients as the treatment for atrial fibrillation develops in the future.

Surgery has been used as a treatment for atrial fibrillation (AF) for more than 20 years. Although highly successful, it has not been widely adopted because operations designed to cure AF require extensive cutting and suturing of the heart, inflicting a significant risk on the patient. Newer technologies now permit the surgeon to create similar scars on the heart as cutting, but much more quickly and safely than before.

Over the last ten years at least six different devices have been developed, each of which can scar the heart: Microwave, radiofrequency, ultrasound, laser and cold are some of them. Although there are many papers in the literature studying these devices, each seems to cure about 80% of patients with very low risk of morbidity and/or mortality. This leaves the surgeon with almost no basis upon which to base his or her selection of a device: Which is the best? Which should be used? Therefore, a comparison study is like this is desperately needed.

At the time of the surgery, surgeon who perform the AF treatment, he or she will select one of the six devices mentioned above at randomly assigned earlier, at the time of the enrollment. The device will be used to make scars on your heart exactly as described in the manufacturer's instructions and according to the surgeon's experience. The operation will then be completed per routine. In other words, the only part of the procedure that will be done differently from any other is that the actual device chosen to perform the ablation will vary from one study subject to another.

Patients will be followed up upto one year with EKGs, Holter monitors, MRI's, 6 minute walk tests, echocardiograms, blood tests like bNP and quality of life questionnaires.

Inclusion Criteria:

• All patients undergoing concomitant cardiac surgery who also have AF.

Exclusion Criteria:

• Patients undergoing re-do or emergency procedures
• Females of child-bearing age who are pregnant
• Age less than 19 and more than 75 years old