Epicardial Ablation on the Beating Heart: Limited Efficacy of a Novel, Cooled Radiofrequency Ablation Device (original) (raw)

2009, Innovations (Philadelphia, Pa.)

OBJECTIVE: To perform a minimally invasive procedure for atrial fibrillation without cardiopulmonary bypass, it is necessary to create transmural lesions on the beating heart. Although bipolar radiofrequency clamps can isolate the pulmonary veins, they have difficulty in performing any other left atrial lesions, particularly those of the traditional Cox-Maze procedure. This study examined the performance of an internally cooled, bipolar radiofrequency device designed for such an application. METHODS: Eleven domestic pigs underwent median sternotomy. Five animals had eight atrial lesions created with the radiofrequency device at times of 20, 30, 40, and 50 seconds. In six other pigs, the device was compared with another technology that has been used clinically for epicardial, beating heart ablation, the Guidant Flex 4 microwave device. The tissue was stained with 2,3,5-triphenyl-tetrazoluim chloride, and the lesions were sectioned at 5-mm intervals. Lesion width, depth, and transmura...