Kardiochirurgia dorosłych
Surgical ablation using the Estech Cobra system in patients with permanent atrial fibrillation treated due to mitral valve disease. A preliminary study

Background:
Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery and the cause of many atherothrombotic complications. AF occurs in 30-40% of patients subjected to cardiac surgery due to mitral valve defect. Replacement or valvuloplasty of mitral valve recovers sinus rhythm only in 10-15% of patients. Current methods of intraoperative ablation using radiofrequency waves are effective methods for the cardiac surgeon, enabling sinus rhythm to be recovered in about 60-90% of patients during routine surgery of the mitral valve.

Aim:
To evaluate the efficacy of the intraoperative ablation system Estech Cobra in patients with atrial fibrillation undergoing mitral valve replacement.

Material and methods:
Between 2005 and 2006, in the Department of Cardiac Surgery, Medical University of Lodz, intraoperative ablation was performed in 12 patients with persistent atrial fibrillation operated upon due to mitral valve disease. The age of the patients ranged from 49 to 76 years, mean 63±8 years, and 8 of them were women (66%). Eight patients (66%) were referred to the surgery due to isolated mitral stenosis being diagnosed and 4 patients (33%) due to combined mitral valve disease (stenosis and insufficiency). In 4 patients (32%), mitral valve disease was accompanied by tricuspid regurgitation (TR) of III/IV degree and in 5 patients (42%) by TR of III degree. The qualification criterion for ablation was persistent AF lasting for more than 6 months. The procedure was performed using the intraoperative radiofrequency ablation system Estech Cobra. After cessation of circulation on cardio-pulmonary bypass (CPB), ablation within the left atrium was conducted and afterwards the valvular defect was corrected. Duration of the ablation was from 12 to 19 minutes, mean 16±5 minutes.

Results:
Directly after the operation, sinus rhythm (SR) was
observed in 10 patients (83%) and after 6 months in 9 patients (75%). Three patients had periodical AF with slow ventricular action. The results were analysed considering left atrium size, duration of preoperative AF and concomitant diseases.

Conclusions:
Intraoperative ablation in patients with atrial
fibrillation subjected to cardiac surgery due to mitral valve defect is a safe method allowing sinus rhythm to be returned in most patients effectively. The obtained results in the early postoperative period show the high efficacy of ablation performed with the ESTECH COBRA system. However, further studies are necessary to confirm these results.