The application of thermography in the study of coronary blood flow

The technique presented in this paper is based on the authors' previous observations in which they found that artificial decrease of blood flow to a portion of the heart muscle leads to an immediate and proportional drop in the regional myocardial temperature. It appeared to the authors as a logical next step to apply the thermographic camera to a monitor and to record such changes in the human patient during coronary surgery and to use the data to draw conclusions applicable to regional blood supply and to blood flow through surgically inserted vein grafts. They found that, on the normothermic heart, there were well-identifiable "cold" patches corresponding with areas of impaired coronary circulation. By infusion of blood to the ischemic myocardium through individual release of the bypass grafts, the thermogram responded by immediate appearance of "warm" spots corresponding with the areas supplied by the grafts. Even more dramatic demonstration of graft patency and outline of the area supplied by the graft could be performed by injecting cold saline solution into the grafted saphenous veins. In the author's experience this most interesting new method proved to be a useful tool in coronary surgery both as an adjunct in delineating ischemic areas and in proving the patency and efficiency of the grafts inserted.