The purpose of this study is to test whether the drug, atorvastatin, will be able to reduce the rate of return of the abnormal beats after using cardioversion. Atorvastatin is a drug approved by the Food and Drug Administration (FDA) for the treatment of high cholesterol but is not approved for preventing abnormal heartbeats. In addition to lowering cholesterol, the drug reduces inflammation. Inflammation seems to help cause atrial fibrillation, a certain type of abnormal heartbeat. In animals, atorvastatin reduces the risk of this type of abnormal beats, and preliminary data in humans supports an effect of atorvastatin and other similar drugs that have the same action on reducing the risk of this type of abnormal beats. We, the researchers at Emory University, would like to learn if this drug could prevent the return of these abnormal heartbeats.