Thermal ablation of perfused porcine left ventricle in vitro with the neodymium-YAG laser hot tip catheter system.
Catheter ablation in the treatment of arrhythmias has been limited by the small lesion size achievable with a radiofrequency energy source. The feasibility of catheter ablation with a neodymium-yttrium-aluminum-garnet (Nd-YAG) laser hot tip catheter was tested because of the capability of achieving a high catheter-tissue contact temperature, which should result in a larger lesion. In a model of isolated perfused pig hearts, 77 endocardial lesions were produced with powers of 1 to 10 watts and peak measured temperatures of 40 degrees to 318 degrees C. Lesion size correlated with power and temperature, but the correlations were poor. High temperature lesions resulted in significant intramyocardial catheter penetration and only marginal increased lesion width. Catheter ablation with a Nd-YAG laser hot tip catheter is feasible, but carries a risk of perforation at high powers. High temperatures result in tissue dessication with a resultant fall in thermal conductivity that limits the radius of thermal injury and overall lesion size.
Haines
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Department of Medicine, University of Virginia Health Sciences Center, Charlottesville 22908.
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000601:surgery; D006328:Cardiac Catheterization; D004564:Electrocoagulation; D005240:Feasibility Studies; D006352:Heart Ventricles / Q000601:surgery*; D066298:In Vitro Techniques; D008028:Light Coagulation / Q000295:instrumentation*; D011846:Radio Waves; D013552:Swine; D013816:Thermodynamics