Comparison between laser and electrical ablation of ventricle in dogs: hemodynamic, pathologic and electrocardiographic observations.

To characterize and compare the pathologic, hemodynamic and electrocardiographic changes of both transcatheter laser and electrical energy on ventricle, 36 subendocardial myocardium lesions were induced at energy 60, 120 and 240 Joules by either transcatheter laser irradiation or electrical shock in 7 anesthetized dogs. The following results were observed: 1) Both laser and electrical ablation on myocardium created nonhomogeneous myocardium injury, but laser ablation caused mainly focal tissue vaporization and necrosis, while electrical shock induced widespread tissue degenerations; 2) Both laser and electrical induced-lesion dimensions increased parallel to the total dosage of energy; 3) Laser ablation caused mainly (90%) single ventricular premature beats and 86% of them occurred within the first minute after energy discharged, while ventricular tachycardias were found in any electrical energy groups; ventricular fibrillations occurring during laser and electrical ablation were 5% and 13% respectively (P < 0.01); 4) A decrease in aortic blood pressure and an increase in central venous pressure induced by laser ablation were significantly less than that produced by the same amount of electrical energy (P < 0.01). Our preliminary results have shown that transcatheter laser ablation has great potential for becoming a practical method in the management of refractory tachycardias.