Effects of early administration of enalapril on radionuclide left ventricular ejection fraction and plasma N-terminal atrial natriuretic peptide after acute myocardial infarction.
The effects of enalapril therapy on radionuclide ejection fraction and plasma N-terminal atrial natriuretic peptide were investigated in a randomized, double-blind, placebo-controlled study of 52 patients with acute myocardial infarction. The medication was begun intravenously within 24 hours of the onset of symptoms. At discharge and the end point of 6 months, the radiographic size of the heart was significantly smaller in patients receiving (n = 28) than in those not receiving (n = 24) enalapril therapy (p < 0.03 vs < 0.01). However, left ventricular ejection fraction decreased simultaneously from 50 +/- 10% to 47 +/- 11% in patients treated with enalapril, whereas it increased from 48 +/- 13% to 50 +/- 14% in control patients (p < 0.05 for the difference of the changes). The decrease in ejection fraction was most marked in the infarct-related region of the left ventricle (p < 0.01). During the in-hospital period, plasma N-terminal atrial natriuretic peptide was decreased in patients treated with enalapril, whereas it was increased in those treated with placebo with complicated acute myocardial infarction (p < 0.05). During the following 6 months, the differences remained insignificant. Early administration of enalapril significantly attenuated heart enlargement after myocardial infarction and probably improved hemodynamics during the acute phase of complicated infarction. The decrease in ejection fraction during recovery indicates an impairment of systolic function. The decrease in infarct-related regional ejection fraction suggests that the impairment may be due to poor healing of the infarction scar.
Kettunen
R V
RV
Department of Internal Medicine, University of Oulu, Finland.
Vuolteenaho
O
O
Ukkola
O
O
Lilja
M
M
Jounela
A
A
Kesäniemi
Y A
YA
Leppäluoto
J
J
Heikkilä
J
J
D000368:Aged; D009320:Atrial Natriuretic Factor / Q000097:blood*; D004311:Double-Blind Method; D004656:Enalapril / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy*; D015635:Radionuclide Ventriculography; D013318:Stroke Volume / Q000187:drug effects*; D013997:Time Factors; D016277:Ventricular Function, Left / Q000187:drug effects*
D004656:Enalapril; D009320:Atrial Natriuretic Factor