Ishikawa Susumu, Oki Shigeru, Muraoka Masato, Oshima Kiyohiro, Kashiwabara Kenji, Morishita Yasuo
Second Department of Surgery, Gunma University Graduate School of Medicine, Gunma, Japan.
Ann Thorac Cardiovasc Surg. 2005 Feb;11(1):21-4.
The effect of epicardial radiofrequency ablation (RFA) during normal heart beating was experimentally studied in order to establish safe and effective procedures for RFA.
Seven pigs weighing approximately 30 to 50 kg were used in this study. Fifty-one epicardial RFA lesions were created on both atria using a Cobra Cooled probe with continuous internal irrigation of a saline solution. The ablation temperature was fixed at 80 degrees C and the duration of the RFA in each case was 20, 30, 60 and 120 seconds.
There was significant positive correlation between the right and left atria in wall thickness. Transmural coagulation was obtained in 69% of the total specimens, which decreased according to the increase of wall thickness especially over 3 mm. Transmural coagulation was seen in 64% of the specimens after RFA of less than 30 seconds, and 86% after ablation of >or=60 seconds. Occurence of 90% or deeper coagulation was higher in the right atrium than in the left one (97% vs. 78%). Right atrial rupture occurred in a region of 1 mm in thickness after ablation of 60 seconds.
Further technical improvements associated with new instruments are indispensable to complete epicardial RFA procedures on a beating heart.
