Histochemical study of transmyocardial laser channels in dogs

Objective Laser-induced myocardial injury was investigated in a canine tran smyocardial laser revascularization model. Methods A total of 23 channels were created in the left ventricles of 5 ani mals with a CO2 laser. Four animals were sacrificed immediately and one at week 2. Lactate dehydrogenase and succinate dehydrogenase in channel region s were examined with a Nitro-BT method staining. Results Immediately after the procedure, laser channels and surrounding inj ured myocardium could be stratified from the center to the border into 5 co ncentric zones, i.e., vaporized zone, carbonized zone, enzyme-disappeared z one, enzyme-decreased zone and enzyme-concentrated zone. Two weeks later, t he phenomenon disappeared. Conclusions Immediately after transmyocardial revascularization, there is a ring of enzyme-concentrated zone at the outermost region of injured myocar dium. Two weeks later, enzyme activities of reversibly injured myocytes app ear to have recovered.