"Abnormal" responses of ejection fraction to exercise, in healthy subjects, caused by region-of-interest selection.
We performed serial exercise equilibrium radionuclide angiography in eight normal subjects with each subject executing three tests: control, after nitroglycerin, and after propranolol. The left-ventricular ejection fraction (EF) was calculated by two methods: (a) fixed region-of-interest (FROI) using a single end-diastolic ROI, and (b) variable region-of-interest (VROI) where an end-diastolic and end-systolic region of interest were used. Abnormal maximal EF responses occurred in five of eight subjects during control using FROI but in zero of eight employing VROI (p < 0.05). After nitroglycerin, three of eight subjects had abnormal responses by FROI, but zero of eight were abnormal by VROI (p < 0.05). After propranolol, blunted EF responses occurred in three of seven by both methods. Falsely abnormal EF responses to execrise RNA may occur due to the method of region-of-interest selection in normal subjects with normal or high ejection fractions.
D000328:Adult; D000792:Angiography / Q000379:methods; D002302:Cardiac Output; D004912:Erythrocytes; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D007553:Isotope Labeling; D008297:Male; D009200:Myocardial Contraction; D005996:Nitroglycerin; D005082:Physical Exertion; D011433:Propranolol; D011877:Radionuclide Imaging; D013318:Stroke Volume
D011433:Propranolol; D005996:Nitroglycerin