REPRODUCIBILITY OF EJECTION-FRACTION DETERMINATIONS BY EQUILIBRIUM RADIONUCLIDE ANGIOGRAPHY IN RESPONSE TO SUPINE BICYCLE EXERCISE - CONCISE COMMUNICATION
Patients (16) with stable, chronic coronary artery disease were studied twice within an average of 15 days to evaluate the reproducibility of ejection fraction (EF) determined by equilibrium radionuclide angiography (EQ) at rest, during supine bicycle exercise (ex) and in the recovery period (rec). After injection of 20-25 mCi of 99mTc-tagged human serum albumin data were analyzed for 2 min periods at rest, during several stages of exercise (submax, max) and during recovery (rec1 = min 2 + 3, rec2 = min 9 + 10). Each patient reached similar (heart rate) .times. (blood pressure) products in the 2 studies: 21,280 .+-. 5200 compared with 20,390 .+-. 4140 mmHg/min. Mean EF for the 1st and 2nd studies were at rest (53.0 .+-. 10.8)%, (52.5 .+-. 10.4)% (r (correlation coefficient) = 0.95); submax ex (51.4 .+-. 12.0)%, (52.1 .+-. 12.8)% (r = 0.91); max ex (50.6 .+-. 12.6)%, (51.6 .+-. 12.9)% (r = 0.97); rec1 (62.7 .+-. 11.6)%, (62.4 .+-. 12.2)% (r = 0.95); rec2 (55.5 .+-. 10.8)%, (57.2 .+-. 11.7)% (r = 0.91). In stable patients the reproducibility of EF determined by EQ is excellent during rest, supine bicycle exercise and recovery from exercise.