Long-term results and reliability of cryothermic ablation based maze procedure for atrial fibrillation concomitant with mitral valve surgery. 
Atrial fibrillation (AF) is the common arrhythmia associated with valvular heart disease, and surgical ablation to treat AF is reported to contribute to eliminate mortality and morbidity.  We report our clinical results of cryomaze procedure obtained in over 10-years' experience.  Since 1998 when we introduced cryoablation to reduce cut-and-sew line, 268 patients (145 males and 123 females, mean age of 61.2-year old) underwent cryomaze procedure concomitant with mitral valve surgery.  We retrospectively obtained preoperative and follow-up data from medical records, and investigated survival rate, freedom from permanent AF recurrence rate and risk factors for recurrence.  Three in-hospital deaths were noted (1.1%), and 243 patients (91.8% of survived patients) were discharged restoring to sinus rhythm.  Pacemaker implantation during hospital stay was required in 12 cases (4.5%).  There were five late deaths, and 5- and 10-year cumulative survival rates were both 93.2%.  Multivariate analysis revealed that huge left atrium, longer history of AF and smaller f-wave in electrocardiogram were the independent risk factors for recurrence of permanent AF.  Older age and re-do cardiac surgery were not significant factors.  Cryoablation based maze procedure for AF adjunct to mitral valve surgery is an effective and long-term promising solution for restoring sinus rhythm.  Patient selection criterion concerning left atrial size, duration of AF and f-wave voltage might be reasonable to improve the results.