Abstract
The experimental study of partial isolation with Nd: YAG Laser was performed. After the right lateral thoracotomy in five dogs, temporal pacing wires were sutured on the free wall of right atrium and right ventricular myocardium. Under overdrive pacing of atrium or ventricle, Nd: YAG laser was delivered continuously on the epicardial surface around pacing wires with cooling on the lased surface with cold saline. The lasing energy was 25J, and 1~2ml per minute cold saline was splashed on the lased surface from side-holes of laser fiber. We used a pen-held type laser probe with the contact tip positioned at the top of 600μquartz fiber. The diameter of the tip was 2.2mm. The pacing sites of myocardium were easily isolated from surrounding myocardium without perforation and charring. The microscopic view of lased myocardium showed well-demarcated and transmural necrosis, which area was larger than that of necrosis made by non-contact lasing because of scattering in tissue. We concluded that laser ablation might be applied to maze procedure for a new method of atrial isolation.
