Circulation time end points. A quantitative comparison of saccharin and radioiodinated albumin as indicators.

ARM-TO-TONGUE CIRCULATION time 11 is widely used as a clinical test for the presence of cardiac failure.'To our knowledge, there have been no objective studies relating the actual time of arrival of an injected substance to its subjectively reported end point. Preliminary observations suggested that a delay of several seconds occurs. Since this represents a significant fraction of the total circulation time, the current study was undertaken to provide more precise information concerning the relationship between the arrival of an indicator and its subjective end point. In patients with cardiac failure and without heart disease, saccharin was injected together with albumin 131I (IHSA) and the arrival time, as noted by taste, was compared with that recorded by an external radiation monitor over the tongue. The characteristics of the radioisotope indicator-arrival curve were also analyzed for each subject.