Between 1992. 2 and 1997. 12, the maze procedure for lone fibrillation or flutter (lone af) was performed in 8 patients including 2 patients with a sustained atrial fibrillation, 5 patients with a paroxysmal atrial fibrillation and 1 patient with a sustained atrial flutter. All patients had suffered from a drug resistance lone af which induced sever symptom that is the dyspnea, palpitation and fatigue. Therefore patients requested to receive the maze procedure, and they agreed with the informed concent. After the maze operation, the normal sinus rhythm was recovered in 7 of 8 patients (87.5%). In only 1 patient, a paroxysmal atrial fibrillation remained but his symptoms improved after surgery. So this operation is a good choice of a treatment for a drug resistance lone af.