Do radionuclide and echocardiographic techniques give a universal cut off value for left ventricular ejection fraction that can be used to select patients for treatment with ACE inhibitors after myocardial infarction?

Objective-To determine whether echocardiography and radionuclide angiography give comparable results when the left ventricular ejection fraction is measured early after myocardial infarction and thus whether, irrespective of the method used, a single value for the ejection fraction could be used as a guide for starting treatment with an angiotensin converting enzyme inhibitor. Design-Prospective comparison of measurement of left ventricular ejection fraction by echocardiography and radionuclide angiography. Setting-Coronary care units of two university teaching hospitals in Glasgow. Patients-99 patients studied within 36 hours of acute myocardial infarction. Outcome measures-Left ventricular ejection fraction assessed by echocardiography and radionuclide angiography. Results-70 (77%) of the 99 patients had ejection fraction measured by both echocardiographic and radionuclide techniques, 30 in centre 1 and 40 in centre 2. In centre 1 the mean difference (SD) in ejection fraction (radionuclide angiography - echocardiography) was -8 (10%); 95% CI - 12 to -4%. In centre 2 the mean difference was -14 (11%); 95% CI -17 to -11%. If patients had been treated with an ACE inhibitor on the basis of a radionuclide ejection fraction of