Surgical ablation of atrial fibrillation (AF) has been gaining ground as the preferred method of treatment of this potentially lethal arrhythmia affecting 1/3-1/2 of patients with mitral valve diseases. It is specially suited for patients undergoing an operative procedure. Between Dec 12,2002 and Dec 29,2003 ,fifty five operative patients with chronic AF were subjected to AF ablation with microwave energy at Damascus University Cardiovascular Surgical Center . Thirty five patients were female; age ranged between 20 and 72 years. All of them had chronic AF.