Influence of the Rate of Coronary Plasma Flow on the Extraction of Rb 86 from Coronary Blood

To determine whether myocardial uptake of Rb 86 can be used as a useful index of coronary plasma flow, the extraction of Rb 86 from arterial plasma during one passage through the myocardium of dogs was measured at varying rates of flow. At rates of flow which are encountered in man, changes in the rates of flow and uptake of isotope by the myocardium paralleled each other closely. Rb 86 uptake is a useful index of coronary blood flow in dogs.