Atrial fibrillation; Maze procedure; Cryoablation; Arrhythmia surgery; Atrial transport function

Aim. The aim of this prospective study was to assess the presence of sinus rhythm (SR) and atrial transport function (ATF) after surgical ablation of atrial fibrillation (AF) using cryoenergy, and to evaluate predictors of the success of the procedure.Methods. Between January 2005 and September 2006, 100 consecutive patients underwent left atrial cryoablation as a concomitant surgical procedure (46 patients with paroxysmal or persistent AF and 54 with permanent AF). Mitral valve surgery was performed in 74%. The mean and the median times of follow-up were 20 +/- 8.5, and 24 months respectively. ATF was assessed by echocardiography. Results. SR was achieved during the postoperative follow-up in 71-81% of patients - significantly more often in the group with paroxysmal and persistent AF (90-98%), than patients with permanent AF prior to surgery (51-65%) (p<0.002). At 12 and 24 months after the surgery, a total of 68.2% and 51.2% of the patients were free from AF; 73.9% and 60.7% of the patients from the paroxysmal and persistent AF group, and 60.3% and 37.7% of patients with permanent AF (p=0.05). Five per cent of patients required postoperative permanent pacemaker implantation. An effective left and right ATF was detected in 70-90%, and 96-98% of patients with SR respectively. The following circumstances were identified as negative predictors of the presence of SR after the ablation procedure: growing diameter of the left atrium, the duration of AF and the severity of mitral and tricuspid regurgitation before surgery (p<0.05). Restoration of the left ATF was negatively predicted by the preoperative diameter of the left atrium, the presence of mitral valve stenosis and the severity of tricuspid regurgitation (p<0.05). A total of 95.4% of patients were free from stroke at one-year follow-up, and 94.1% at 2 years after surgery.Conclusion. Stable SR and effective left ATF are the main factors resulting in decreased morbidity after successful ablation of AF.