| For the purpose of demonstrating the feasibility, effectiveness and safety of clinical application of laser photocoagulation in the treatment of tachyarrhythmias, the following animal experiments were carried out:(l) the influence of various physical factors on the lesion size produced by laser irradiation was assessed;(2) the evolution of morphological pathology and cellular electrophysiological alterations after laser photocoagulation(LP) was compared with those after radiofrequency current ablation(RFCA);(3)laser ablation of His bundle via fiberoptic wire was undertaken percutaneously and laser ablation of VT induced by aconitine was performed via thoractomy .Methods: 1.Porcine hearts were used to assess the influences of various factors on laser ablation: specimen were divided into subgroups according to different fiber-optic wire diameters and/or whether they were underwent normal saline irrigation. Different levels of power and duration were adopted and the size and depth of the resulting craters and lesions were estimated to observe the dose-response relationships. Lesions resulted by using identical parameters with RF current ablation were also observed for comparison. 2. laser and RF current ablation on epicardial surface of rat hearts were performed to observe the histo-pathological characteristics. 3. After laser photocoagulation was performed with 25 J energy on the endocardial tissues removed from rabbit hearts, transmembrane potentials were recorded with intracellu-lar glass microelectrodes at various distance from the boundary of the lesions to study the cellular electrophysiologic characteristics of injured but nonnecrotic myocardium around the lesions. The same procedure were carried out using radiofrequency ablation with the same level of... |
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