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.


METHODS
Prospective comparison of measurement of left ventricular ejection fraction by echocardiography and radionuclide angiography.


METHODS
Coronary care units of two university teaching hospitals in Glasgow.


METHODS
99 patients studied within 36 hours of acute myocardial infarction.


METHODS
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 < 40% then 93% in centre 1 (28 of 30) and 98% in centre 2 (39 of 40) would have been treated. This compares with 63% (19 of 30) and 50% (20 of 40), respectively if echocardiography had been used as a guide.


CONCLUSIONS
Measurement of ejection fraction is highly dependent on the method used and it is therefore impossible to quote a universally applicable figure for left ventricular ejection fraction below which an ACE inhibitor should be used after myocardial infarction.
Ray
S G
SG
Department of Cardiology, Western Infirmary, Glasgow.
Metcalfe
M J
MJ
Oldroyd
K G
KG
Pye
M
M
Martin
W
W
Christie
J
J
Dargie
H J
HJ
Cobbe
S M
SM
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D004452:Echocardiography; D006801:Humans; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000188:drug therapy*; D018579:Patient Selection; D011875:Radionuclide Angiography; D013318:Stroke Volume
D000806:Angiotensin-Converting Enzyme Inhibitors