The role of laser-induced fluorescence in myocardial tissue characterization - An experimental in vitro study

Objective: The fluorescence of tissue when stimulated by a laser beam is a well-known phenomenon, The resulting emission spectra depend on the biochem ical and structural composition of the tissue. In this study, we examined t he spectra off laser-induced fluorescence emitted by myocardial tissue. Methods: We used an argon-ion laser to stimulate the myocardium of 20 intac t sheep hearts. For each spectral emission, we calculated the intensity in specific regions in order to characterize the spectra and to reveal interca vitary and intracavitary morphologic differences. Results: The statistical analysis showed significant differences in the emi ssion spectra intensity between atria and ventricles. The intensity was hig her in the atria than in the ventricles (p < 0.001). The atrial emission sp ectra were morphologically different from those of the ventricles. There wa s no difference in the intensity or morphology of emission spectra within e ach chamber. All measurements showed good reproducibility after a short per iod of time. Conclusions: Laser-induced fluorescence of myocardial tissue seems to have the characteristics necessary for tissue recognition. This might prole usef ul in identifying cardiomyopathies and transplant rejection, as well as for myocardial mapping, assisting electrophysiologists in discovering fibrotic arrhythmogenic foci.