Unrecognized myocardial infarction: the association with cardiopulmonary symptoms and mortality is mediated via echocardiographic abnormalities of global dysfunction instead of regional dysfunction: the Olmsted County Heart Function Study.
BACKGROUND
There are very few data describing the association of electrocardiogram-based unrecognized myocardial infarction (ECG-UMI) with nonanginal cardiopulmonary symptoms, echocardiographic abnormalities, and mortality in the community.


METHODS
We studied 2042 Olmsted County residents, who were randomly selected and aged > or = 45 years, by a survey questionnaire for symptoms, echocardiogram for structural abnormalities, and a 5-year follow-up for all-cause mortality. Unrecognized myocardial infarctions (n = 81) were diagnosed if ECG-based myocardial infarction (MI) criteria were met without the history of a documented recognized MI.


RESULTS
In UMI versus no MI controls, the prevalence (%) of dyspnea on exertion (49 vs 29), orthopnea (6 vs 4), palpitations (20 vs 15), and history of fluid overload (6 vs 1) was significantly higher (P < .05). The associations of exertional dyspnea and history of fluid overload with UMI were independent of age, sex, and pulmonary disease but had a significant reduction in their magnitude after adjusting for global dysfunction (diastolic or systolic dysfunction). All the 4 symptoms were associated with increased risk of mortality (hazard ratios ranging from 2.3 to 9.1, P < .0001), which was meaningfully attenuated by adjusting for ECG-UMI status. Global ventricular dysfunction had a more significant impact on this association than regional ventricular dysfunction (wall motion abnormalities).


CONCLUSIONS
The increased risk of mortality associated with symptoms is at least in part mediated via ECG-UMI. Structural abnormalities of global dysfunction play a greater role in mediating this risk than regional dysfunction, challenging the current clinical practice of calling an ECG-based MI false positive in symptomatic adults in the absence of wall motion abnormalities.
Ammar
Khawaja Afzal
KA
Division of Cardiovascular Diseases, Mayo Clinic and Foundation, Rochester, MN, USA. ammar.khawaja@mayo.edu
Makwana
Ravindrakumar
R
Redfield
Margaret M
MM
Kors
Jan A
JA
Burnett
John C
JC
Rodeheffer
Richard J
RJ
D000368:Aged; D004417:Dyspnea / Q000453:epidemiology; D004562:Electrocardiography; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000401:mortality; D020097:Natriuretic Peptide, Brain / Q000097:blood; D016016:Proportional Hazards Models; D013318:Stroke Volume; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000401:mortality
D020097:Natriuretic Peptide, Brain