 Atrial fibrillationAF is the most common sustained arrhythmia. It can cause reduced heart function and increase the risk of thromboembolism. About 60 of patients with rheumatic heart disease have persistent AF.AF surgery is an effective intervention for patients with all types of AF undergoing concomitant cardiac surgery. AF surgery can reduce the risks of heart of stroke and heart failure and promote longer survival. Bipolar radiofrequency ablation is one of the most effective ways. But in the investigators early study we find that there are technique blind spots in the left atrial ablation and right atrial ablation. In the bipolar left atrial linear ablation performed along the lower edge of interatrial groove incision up to the mitral annulus, there is a gap between the ends of the ablation line to the mitral annulus. And if the investigators use bipolar radiofrequency pliers it may injure the lcx left circumflex artery and left ventricular. In the bipolar right atrial radiofrequency ablation, the linear ablation performed along the lower edge of the coronary sinus ostium up to the inferoseptal commissure and the linear performed through the vertical incision on anterior wall of the right atrium up to the tricuspid annulus, there is also a gap between the end of the end of the ablation line and the tricuspid annulus. These gaps are one of factors of the recurrence of AF. 