BACKGROUND: Catheter ablation of postinfarction @entity1165 ( @entity1165 ) may be limited by insufficient @entity296 or excessive @entity16 . We propose that volumetric heating restricted to intramural sites may improve the outcome and safety of this procedure, especially if delivered at rates that enhance heat conduction and forestall adverse tissue changes. METHODS AND RESULTS: A novel optical fiber with a diffusing tip for direct intramural, volumetric laser heating was tested via thoracotomy and percutaneously in normal @entity235 . Low-power (2.0- to 4.5-W) diode laser light (805 nm) diffused within tissue induced large lesions but no visible surface damage, mural thrombi, or transmural perforation. Mean lesion depth approximated tip length (10 mm). Mean lesion widths in the thoracotomy and percutaneous groups were 5.8+/-0.5 to 9.1+/-0.84 mm and 5.2+/-0.85 to 7.9+/-1.1 mm, respectively, depending on the light dose. Mean volumes in the percutaneous group were 1006+/-245 to 2471+/-934 mm. @entity308 , appearing in unfiltered bipolar electrograms recorded from the guiding catheter, was specific for lesion induction. All @entity235 survived the protocol, which included a 1-hour observation period. In cross section, lesions were elliptical to spherical and characterized by extensive contraction-band @entity39 abruptly bordering viable tissue. No platelets or fibrin adhered to the endocardium. CONCLUSIONS: Slow, volumetric, and direct intramyocardial heating induces large, @entity75 without hazardous tissue damage. Such heating might cure postinfarction @entity1165 more successfully and safely than present techniques. Further testing and development of this method seem warranted.

Slow intramural heating with diffused laser light: A unique method for deep XXXX .

@entity296 :: ('MESH:D009202', 'Disease') :: ['myocardial coagulation'] @entity1165 :: ('MESH:D017180', 'Disease') :: ['VT', 'ventricular tachycardia'] @entity308 :: ('MESH:D003866', 'Disease') :: ['ST-segment depression'] @entity39 :: ('MESH:D009336', 'Disease') :: ['necrosis'] @entity235 :: ('9615', 'Species') :: ['dogs'] @entity75 :: ('MESH:D001927', 'Disease') :: ['deep lesions'] @entity16 :: ('MESH:D009422', 'Disease') :: ['endocardial or epicardial damage']
@entity296 :: (MESH:D009202,Disease) :: ['myocardial coagulation']
