Clearance of Rb 86 from Coronary Blood by the Atria of Dogs. ∗

Summary

The rate of clearance of Rb⁸⁶ from blood by several areas of the atria was studied in 18 dogs because of evidence that Rb⁸⁶ uptake and rate of coronary blood flow are closely related. Mean rates of clearance averaged 0.40 ml blood/g/min. These were not significantly different in the right atrium, left atrium and interatrial septum. Rb⁸⁶ uptake by the atria formed a larger portion of total myocardial uptake when cardiac output was low. Frequently the clearance per gram of tissue exceeded that found simultaneously in the ventricles. This indicates that atrial flow is better maintained when the animal is in poor condition than is flow to the ventricles.