| Transmyocardial laser revascularization (TMLR) is a surgical procedure whereby laser energy is used to create transmural channels in the left ventricle (LV). To minimize the creation of gaseous emboli when the laser beam contacts blood in the LV, a penetration detection mechanism is needed. In this study, laser shock waves were examined as a possible indication source for ventricular penetration of the XeCl 308 nm excimer laser beam during TMLR. Analysis of the sound files recorded during lasing of different levels of hematocrit: low (0.028%), medium (0.281%) and high (0.839%), showed that increased numbers of chromophores at higher hematocrit levels translated into greater absorption of laser energy. Analysis of the sound files of the in-vitro adaptation of TMLR in porcine model showed blood absorbed more of the incident laser energy than myocardium. The difference in absorbance levels of the laser energy translated as a change in the amplitude of the audio signals clearly indicated when the laser penetrated through blood and when it penetrated through myocardium. |
