title: Prevalence of unrecognized myocardial infarction in a low-intermediate risk asymptomatic cohort and its relation to systemic atherosclerosis.
abstract: OBJECTIVE
  Unrecognized myocardial infarctions (UMIs) have been described in 19-30% of the general population using late gadolinium enhancement (LGE) on cardiac magnetic resonance. However, these studies have focused on an unselected cohort including those with known cardiovascular disease (CVD). The aim of the current study was to ascertain the prevalence of UMIs in a non-high-risk population using magnetic resonance imaging (MRI).
  
  
  RESULTS
  A total of 5000 volunteers aged >40 years with no history of CVD and a 10-year risk of CVD of <20%, as assessed by the ATP-III risk score, were recruited to the Tayside Screening for Cardiac Events study. Those with a B-type natriuretic peptide (BNP) level greater than their gender-specific median were invited for a whole-body MR angiogram and cardiac MR including LGE assessment. LGE was classed as absent, UMI, or non-specific. A total of 1529 volunteers completed the imaging study; of these, 53 (3.6%) were excluded because of either missing data or inadequate LGE image quality. Ten of the remaining 1476 (0.67%) displayed LGE. Of these, three (0.2%) were consistent with UMI, whereas seven were non-specific occurring in the mid-myocardium (n = 4), epicardium (n = 1), or right ventricular insertion points (n = 2). Those with UMI had a significantly higher BNP [median 116 (range 31-133) vs. 22.6 (5-175) pg/mL, P = 0.015], lower ejection fraction [54.6 (36-62) vs. 68.9 (38-89)%, P = 0.007], and larger end-systolic volume [36.3 (27-61) vs. 21.7 (5-65) mL/m2, P = 0.014]. Those with non-specific LGE had lower diastolic blood pressure [68 (54-70) vs. 72 (46-98) mmHg, P = 0.013] but no differences in their cardiac function.
  
  
  CONCLUSIONS
  Despite previous reports describing high prevalence of UMI in older populations, in a predominantly middle-aged cohort, those who are of intermediate or low cardiovascular risk have a very low risk of having an unrecognized myocardial infarct.
authors.affiliation: Department of Cardiovascular and Diabetes Medicine, College of Medicine, Ninewells Hospital, University of Dundee, Level 7, Dundee DD1 9SY, UK.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Weir-McCall
authors.affiliation: Department of Cardiovascular and Diabetes Medicine, College of Medicine, Ninewells Hospital, University of Dundee, Level 7, Dundee DD1 9SY, UK.
authors.forename: Kerrie
authors.initials: K
authors.lastname: Fitzgerald
authors.affiliation: Department of Cardiovascular and Diabetes Medicine, College of Medicine, Ninewells Hospital, University of Dundee, Level 7, Dundee DD1 9SY, UK.
authors.forename: Carla J
authors.initials: CJ
authors.lastname: Papagiorcopulo
authors.affiliation: NHS Tayside Medical Physics, Ninewells Hospital, Dundee, UK.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Gandy
authors.affiliation: Department of Cardiovascular and Diabetes Medicine, College of Medicine, Ninewells Hospital, University of Dundee, Level 7, Dundee DD1 9SY, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Lambert
authors.affiliation: Department of Cardiovascular and Diabetes Medicine, College of Medicine, Ninewells Hospital, University of Dundee, Level 7, Dundee DD1 9SY, UK.
authors.forename: Jill J F
authors.initials: JJF
authors.lastname: Belch
authors.affiliation: NHS Tayside Medical Physics, Ninewells Hospital, Dundee, UK.
authors.forename: Ian
authors.initials: I
authors.lastname: Cavin
authors.affiliation: Department of Cardiovascular and Diabetes Medicine, College of Medicine, Ninewells Hospital, University of Dundee, Level 7, Dundee DD1 9SY, UK.
authors.forename: Roberta
authors.initials: R
authors.lastname: Littleford
authors.affiliation: NHS Tayside Medical Physics, Ninewells Hospital, Dundee, UK.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Macfarlane
authors.affiliation: Department of Cardiovascular and Diabetes Medicine, College of Medicine, Ninewells Hospital, University of Dundee, Level 7, Dundee DD1 9SY, UK.
authors.forename: Shona Z
authors.initials: SZ
authors.lastname: Matthew
authors.affiliation: NHS Tayside Medical Physics, Ninewells Hospital, Dundee, UK.
authors.forename: R Stephen
authors.initials: RS
authors.lastname: Nicholas
authors.affiliation: Department of Cardiovascular and Diabetes Medicine, College of Medicine, Ninewells Hospital, University of Dundee, Level 7, Dundee DD1 9SY, UK.
authors.forename: Allan D
authors.initials: AD
authors.lastname: Struthers
authors.affiliation: Department of Research and Innovation, North York General Hospital, University of Toronto, Toronto, UK.
authors.forename: Frank M
authors.initials: FM
authors.lastname: Sullivan
authors.affiliation: NHS Tayside Medical Physics, Ninewells Hospital, Dundee, UK.
authors.forename: Shelley A
authors.initials: SA
authors.lastname: Waugh
authors.affiliation: Department of Clinical Radiology, University Hospital of Wales, Cardiff, UK.
authors.forename: Richard D
authors.initials: RD
authors.lastname: White
authors.affiliation: Department of Cardiovascular and Diabetes Medicine, College of Medicine, Ninewells Hospital, University of Dundee, Level 7, Dundee DD1 9SY, UK.
authors.forename: J Graeme
authors.initials: JG
authors.lastname: Houston
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D058070:Asymptomatic Diseases / Q000453:epidemiology*; D050197:Atherosclerosis / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000503:physiopathology; D015331:Cohort Studies; D005260:Female; D005682:Gadolinium; D064368:Healthy Volunteers; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000473:pathology; D015995:Prevalence; D011379:Prognosis; D011856:Radiographic Image Enhancement; D018570:Risk Assessment; D012737:Sex Factors
chemical_list: D005682:Gadolinium
keywords: atherosclerosis; cardiac magnetic resonance; myocardial infarction; whole-body MRI