LASER VERSUS RADIOFREQUENCY CATHETER ABLATION OF VENTRICULAR MYOCARDIUM IN DOGS - A COMPARATIVE TEST

To compare the effects of laser light with those of radiofrequency (RF ) current on ventricular myocardium, a total of 36 lesions (endocardia l approach n = 10 each and epicardial approach n = 8 each) were produc ed by either transcatheter laser (Nd:YAG, 1,064 nm, 30 W, 30 s) or RF (70 degrees C, 30 s) catheter applications in the beating hearts of 4 dogs. Volumes of coagulated myocardium in endo-/epicardial approaches were 996 +/- 73/1,075 +/- 82 (laser) and 111 +/- 38/44 +/- 5 mm(3) (RF ). RF lesions showed intramural bleeding, rupture and dissociation of myocardial fibers, tissue vaporization with crater and thrombus format ion. Transcatheter application of laser light produced significantly l arger and better reproducible lesions than RF current, without undesir able effects on the ventricular walls.