 Should cardioversion be successful, a limited 2D echocardiogram will be done and the following information will be measured: atrial electromechanical interval, left atrial volume, left atrial size, ejection fraction, and maximal A-wave transmitral Doppler flow velocity. The presence of left ventricular hypertrophy and valvular heart disease will be recorded. In addition, baseline clinical information including age, gender, medications, presence of HTN, DM, CAD, stroke, and prior history of atrial fibrillation will be obtained. 