This is a study of different techniques for treatment of atrial fibrillation using a procedure called radiofrequency catheter ablation. Atrial fibrillation (called AF) is when the upper chambers of the heart (the atria) beat much faster than the lower chambers, causing the heart to beat less effectively. AF can cause stroke, impaired performance, palpitations, shortness of breath, passing out and other symptoms. Radiofrequency ablation involves placement of catheter/electrode wires into the heart through plastic tubes inserted into veins / arteries in both the groins and the right side of the neck under local anesthesia. Radiofrequency energy is delivered to the areas inside the heart that cause the rapid firing of the atria, causing small lesions or "burns" that destroy the heart tissue where the extra electrical impulses come from. Commonly this area is where the four pulmonary veins (PV) deliver blood from the lungs to the left side of the heart, and the procedure is also referred to as "pulmonary vein isolation" or PVI.