Measurement of Circulation Times with NaI¹³¹

¹ Radioisotope Service, Veterans Administration Hospital; the Department of Medicine, Western Reserve University, Cleveland, Ohio

Circulation time from an arm vein to the femoral artery as determined with I¹³¹ averaged 11.2 seconds in normal male adults. In the presence of heart failure the time of initial arrival was prolonged, and the slope of ensuing rise flattened. Decholin time, determined simultaneously, averaged 25 per cent longer than I¹³¹ time in both normal subjects and patients with congestive failure. Theoretical considerations indicate that arrival time measured with a radioactive tracer is less affected by cardiac dilatation than is arm to tongue time obtained with Decholin. Arm to heart time measured with I¹³¹ was prolonged in the presence of failure but marked overlap with normal subjects was evident.