The incidence of unrecognized myocardial infarction in women with coronary heart disease.
BACKGROUND
Several cohort studies in populations without coronary heart disease have demonstrated that up to 40% of incident myocardial infarctions are clinically unrecognized.


OBJECTIVE
To determine the incidence of unrecognized myocardial infarction in women with coronary heart disease in the Heart and Estrogen/progestin Replacement Study (HERS).


METHODS
Randomized, double-blind, placebo-controlled trial of conjugated estrogens plus medroxyprogesterone or identical placebo with 4.1 years of follow-up.


METHODS
Outpatient and community settings at 20 U.S. clinical centers.


METHODS
2763 postmenopausal women younger than 80 years of age with coronary heart disease and an intact uterus.


METHODS
Annual electrocardiograms were obtained for all participants during follow-up (mean, 4.1 years) and were evaluated by using the NOVACODE computer algorithm and visual confirmation. A total of 13 715 electrocardiograms were obtained. Suspected unrecognized myocardial infarctions were investigated by comparing a participant's previous surveillance electrocardiograms with the electrocardiograms obtained from all of her intervening hospitalizations. Characteristics of patients with recognized and unrecognized myocardial infarction were compared.


RESULTS
Among the 256 nonfatal myocardial infarctions, 11 were unrecognized (4.3% [95% CI, 2.2% to 7.6%]). Seven occurred in women assigned to placebo and 4 occurred in women assigned to hormone therapy (P > 0.2). Women with unrecognized myocardial infarction were less likely to have diabetes mellitus or previous angina and were more likely to have had previous bypass surgery compared with women who had clinically recognized myocardial infarction.


CONCLUSIONS
The incidence of unrecognized myocardial infarction in women with coronary disease was far lower than that observed in previous studies of populations without coronary heart disease.
Shlipak
M G
MG
General Internal Medicine Section (111A-1), Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA. shlip@itsa.ucsf.edu
Elmouchi
D A
DA
Herrington
D M
DM
Lin
F
F
Grady
D
D
Hlatky
M A
MA
D000368:Aged; D003327:Coronary Disease / Q000150:complications*; D004311:Double-Blind Method; D004562:Electrocardiography; D015914:Estrogen Replacement Therapy / Q000379:methods; D004966:Estrogens, Conjugated (USP) / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008525:Medroxyprogesterone / Q000627:therapeutic use; D009203:Myocardial Infarction / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D017698:Postmenopause; D045167:Progesterone Congeners / Q000627:therapeutic use; D012307:Risk Factors
D004966:Estrogens, Conjugated (USP); D045167:Progesterone Congeners; D008525:Medroxyprogesterone