THE DISTRIBUTION OF THE CORONARY BLOOD FLOW

Abstract

A method is described for measuring total coronary inflow, drainage from the coronary sinus, drainage from the Thebesian vessels and accessory veins of the right heart, and drainage from the Thebesian vessels and accessory veins of the left heart in an isolated, fibrillating dog''s heart with the 3 main coronary branches perfused with defibrinated blood at constant pressure and temp. The results of 12 expts. are reported. The proportion of total coronary flow carried by each of the 3 main coronary arteries (It. circumflex, ant. It. descending, and rt. circumflex) was found to be widely-variable in different individuals. Evidence is presented to show the probable existence of functional anastomoses between the three main coronary arteries in some animals. The proportion of total outflow carried by each of the 3 drainage channels was found to be widely variable in different individuals. In particular, the proportion drained by the coronary sinus varied from 17%-44% with an average of 32%. These results are not in accord with the almost constant sinus drainage of 60% reported by Anrep, Blalock and Hammouda. The differences in coronary sinus drainage between the beating and fibrillating heart are discussed. The distr. of blood from each of the 3 main coronary arteries to each of the 3 drainage channels was found to be widely variable in different individuals. The invalidity of using coronary sinus outflow as an index of total coronary flow is further substantiated.