title: First-third ejection fraction: is the first-pass radionuclide method accurate?
abstract: Previous reports have suggested that left ventricular first-third ejection fraction (EF) can be obtained from the left ventricular time-activity curve derived from first-pass radionuclide angiography based on Anger camera data. The validity of this technique was assessed by: a study of beat-to-beat variations in data from 15 patients in which electrocardiographic data were simultaneously recorded, and a computer simulation incorporating the application of Poisson statistics to appropriate count rate data. The results of patients studies showed no consistent trend in any first-third parameter obtained from consecutive beats in individual subjects, and unacceptably high statistical uncertainty in the calculation of the first-third ejection fraction. The weighted standard deviation of the first-third ejection fraction in each of 15 patients studied averaged 7.5 EF units, while first-third ejection fraction averaged 22.9 EF units. The relative error averaged 32%. The computer simulation indicated a high relative error of 47% associated with the first-third ejection fraction at typical end-diastolic count rates of 200 per frame from 1,000 computer Poisson randomizations of an appropriate analog volume curve. The results render the first-pass radiocardiographic method invalid for determining first-third ejection fraction.
mesh_terms: D000328:Adult; D000368:Aged; D002302:Cardiac Output; D003201:Computers; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006331:Heart Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006349:Heart Valve Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D011336:Probability; D011877:Radionuclide Imaging; D013318:Stroke Volume