Delineation of myocardial ischemia in an isolated blood-perfused rabbit heart preparation

Abstract

Isolated perfused heart preparations provide controlled conditions for the study of myocardial respiration and metabolism. Most studies utilize a hemoglobin-free perfusate which requires high arterial oxygen tension and high coronary perfusion rate. A blood-perfused rabbit heart preparation using an "assist" rabbit to maintain blood homeostasis has been developed which is suitable for respiratory, metabolic, and spectroscopic studies of myocardial function under controlled conditions. Fluorescence emission of reduced nicotinamide adenine dinucleotide (NADH) from the surface of blood-perfused rabbit heart was photographed to delineate areas of myocardial ischemia detectable as NADH fluorescence from reduced mitochondria. Blood reperfusion of ischemic myocardium resulted in disappearance of NADH fluorescence. Reocclusion of the coronary artery resulted in the same pattern and amplitude of NADH fluorescence.