Safety and Efficacy of the CoolCryo System for Cardiac Cryoablation in the Treatment of Atrial Fibrillation

Inclusion Criteria: 1. Written consent from the patient to participate in the study. 2. age ≥18 years. 3. patient qualified for mitral valve surgery (mitral valve plication or mitral valve replacement "with" or "without" left atrial appendage closure). 4. a documented diagnosis of co-occurrence of paroxysmal or persistent atrial fibrillation (AF) since at least 3 months prior to surgery with exclusion of acute conditions. Exclusion Criteria: 1. Lack of written consent from the patient to participate in the study. 2. Failure to meet the inclusion criteria. 3. Contraindications to the cryoablation procedure. 4. Patient breastfeeding, pregnant or planning pregnancy within 6 months of study treatment. 5. co-morbidities and/or conditions that may cause atrial fibrillation (uncompensated hyperthyroidism or hypothyroidism, acute infection, pheochromocytoma, significant dyselectrolitemia). 6. significant calcification of the left atrium. 7. Condition after previous cardiac surgery. 8. significant left atrial enlargement (size greater than 10 cm on echocardiography in one of the projections performed). projection). 9. the patient is currently a participant in another clinical trial. 10. The patient is on active biological therapy. 11. emergency surgery. 12. Life expectancy \<12 months. 13. Any circumstances that, in the opinion of the Investigator, may prevent the patient from participating in the study, limit the ability to perform the procedures outlined in the study protocol or place an unreasonable risk on the patient.