M. Knaut1, S. Brose1, R. Forker1, F. Jung2, K. Matschke1
1Department of Cardiac Surgery, Heart Centre Dresden, Technical University, Dresden, Germany; 2Center for Biomaterial Development and Berlin Brandenburg Center for Regenerative Therapies (BCRT), GKSS Research Center Geesthacht GmbH, Teltow, Germany
[Applied Cardiopulmonary Pathophysiology 13: 284-290]
Background: Atrial fibrillation (AF) which is one of the most common arrhythmias is responsible for a high percentage of strokes. Recently simplified ablation procedures became more relevant in the surgical treatment of AF. One advantage of microwave ablation (MW) is, that it can be used epicardially. We report our first clinical results of the use of epicardial MW as a concomitant procedure during cardiac surgery where opening of the left atrium was not required.
Methods: Patients who were scheduled for aortic valve replacement and/or coronary artery bypass grafting suffering from permanent AF, were included into the registry. They received epicardial MW as a concomitant procedure during their operation and were followed over a period of one year. The results were compared to the outcome of a historical patient group with equivalent operations without ablation therapy. Epicardial MW was done on extracorporeal circulation on the beating heart creating box lesions around the pulmonary veins with a connection line on the roof of the left atrium and an additional line to the left atrial appendage.
Results: 40 patients were treated with epicardial MW in combination with aortic valve replacement and/or coronary artery bypass grafting. Their preoperative data were as follows: age: 69.6±7.8 years, ejection fraction: 55.7±14.2%, left atrial diameter: 46.2±6.0 mm, duration of AF 6.8±9.8 years. The control group comprised 145 patients (age: 72.6±6.9 years, ejection fraction: 49.7±14.8%, left atrial diameter: 47.4±6.6 mm, AF history: 3.7±5.7 years). One year survival rate was 92.5 % in the ablation group and 86.9 % in the control group. We observed no device-related complications. During the follow-up the sinus rhythm rate ranged between 71.4 and 65.7% in the ablated patients in contrast to 7.4 to 9.6% in the control group (p=0.00001).
Conclusion: Our results demonstrate that epicardial ablation, in this study with a microwave ablation device, is an effective treatment option for patients with permanent AF. The procedure is less invasive then the endocardial approach and prolongs concomitant heart surgery only minimally without lengthening ischemic time. Epicardial ablation has become part of the daily routine in our institution for the treatment of AF in patients scheduled for bypass grafting and/or aortic valve replacement.
Key words: epicardial ablation, microwave energy, coronary artery bypass grafting, aortic valve replacement and permanent atrial fibrillation
Address for corresponding:
PD Dr. Michael Knaut, Dresden Heart Institute, Technical University Dresden, Fetscherstr. 76, 01307 Dresden, Germany