To determine the thermal responses of cardiovascular tissues to laser and electrical ablation, and to characterize the effects of different superfusing media and temperatures on target tissue temperatures and resulting extent of tissue injury, 184 laser and 15 electrical discharges were delivered to segments of human and canine aorta and canine ventricular endocardium. Tissue temperatures were measured 2 mm from the point of contact of laser fiber tip and tissue. When superfusing media consisted of whole blood or plasma at room temperature, a standard 40 J laser discharge caused peak arterial temperatures to rise 29.2 +/- 1.6 degrees C and 30 +/- 1.4 degrees C, respectively; however, tissue cooling was significantly slower in blood than in plasma. When saline solution was superfused, tissue temperatures rose by 11.4 +/- 2.2 degrees C, and tissue cooling occurred significantly faster than with either plasma or blood. The dimensions of the resulting aortic lesions were larger when blood (1.69 +/- 0.26 mm) was superfused than when plasma (1.39 +/- 0.04 mm) or saline (0.77 +/- 0.13 mm) was superfused (p less than 0.0001). Similar findings were observed with ventricular endocardium using blood or saline as the superfusing medium. In arterial tissue, superfusion with cold blood or saline solution resulted in lower peak temperature elevations (22 +/- 3.8 degrees C and 13.5 +/- 1.3 degrees C, respectively) and faster tissue cooling after laser discharge. Corresponding aortic lesion sizes were significantly smaller (1.4 +/- 0.03 and 0.5 +/- 0.02 mm, respectively) than when blood or saline medium was superfused at room temperature (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.