Angiotensin-converting enzyme (ACE) inhibitor therapy after myocardial infarction in relation to left ventricular function

Abstract

Objective - To investigate to what extent and by what methods clinicians assess left ventricular (LV) function after an acute myocardial infarction (AMI) and how the results of the assessments relate to the use of angiotensin-converting enzyme (ACE) inhibitors; furthermore, to explore which main indications caused the clinicians to initiate ACE inhibitor therapy. Design - From 16 hospitals we drew a sample of patients who were discharged with the diagnosis of AMI during a 3-month period in 1999/2000. Physicians in each hospital obtained the observed rate of use of cardiovascular drugs at discharge and also information on ejection fraction (EF) measurements. The results of the EF recordings were classified into three categories: >0.50, 0.40-0.50 and <0.40. The clinicians' main indications for drug use were reported. Results - Among 767 patients discharged alive, EF was measured in 409 (53%), by echocardiography in 53% and by radionuclide ventriculography in 47%. Of the 409 patients 227 (55%) had EF >0.50, 95 (24%) EF 0.40-0.50 and 87 (21%) EF <0.40. Adjusted odds ratio for ACE inhibitor therapy being initiated during the AMI was 13.5 for those with EF <0.40 compared with those with EF >0.50. The main indication for starting ACE inhibitor therapy was heart failure (50%) followed by secondary prevention (42%). Conclusion - Measuring EF appears to be an important tool in the evaluation of AMI patients prior to discharge from hospital. Initiation of ACE inhibitor therapy related strongly to the results of the assessments.