INTRAOPERATIVE RADIOFREQUENCY MICROBIPOLAR COAGULATION TO REPLACE INCISIONS OF MAZE-III PROCEDURE FOR CORRECTING ATRIAL-FIBRILLATION IN PATIENTS WITH RHEUMATIC VALVULAR DISEASE

Objective. Radiofrequency catheter ablation of atrial tachycardias and flutter is an established technique. The same modality in the microbi polar mode is effective in producing full thickness coagulation injury . Cox's maze procedure is highly successful in curing atrial fibrillat ion (AF) surgically. However, it consumes relatively long cross clamp time and cardiopulmonary bypass time. In this study, radiofrequency mi crobipolar coagulation was used as an adjunct to corrective valve surg ery, as an intraoperative ablative modality to replace Cox's maze III incisions, thus remarkably shortening the procedure. The results of th is procedure are compared historically with those of 26 patients who u nderwent corrective valve surgery alone. Methods: Radiofrequency micro bipolar coagulation was used to produce conduction blocks along the Co x's maze III incision lines as an adjunct to valve surgery in 18 patie nts in atrial fibrillation undergoing surgery for rheumatic valvular d isease. A bayonet type bipolar forceps with an active tip length of 7 mm drawing current from a microbipolar port of Valleylab Force 4 elect rosurgical unit (Valleylab, Boulder, CO) was used for microbipolar coa gulation. A 3-mm retinal handheld cryoprobe working on nitrous oxide g as was used for cryoablation, Results: A total of 15 survivors in the coagulation maze group were followed from 43 to 224 days (149.7 +/- 73 .1 mean +/-S.D.). Twelve of the 15 survivors (80%) converted to normal sinus rhythm (70% confidence limit: 64.7-90.6%). Atrial transport fun ction studies with pulsed wave doppler, showed presence of a wave in a ll the 12 (100%) patients in tricuspid valve flow and in nine (75%) pa tients in mitral valve flow. The procedure took 11.62 +/- 3.86 min of elective cardioplegic arrest time for the left atrial portion and 18.7 1 +/- 4.25 min of cardiopulmonary bypass time during reperfusion for t he right atrial portion. Of the 23 survivors out of 26 patients who un derwent the valve procedure alone, only one patient (4.3%) converted t o normal sinus rhythm (70% confidence limit: 0.6-14%). Conclusion: Thu s, our modification considerably shortened the time taken for creating the maze in comparison to the Cox's maze procedure and was effective in restoring normal sinus rhythm in 80% of the patients. (C) 1997 Else vier Science B.V.