title: Prevalence and incidence of Q-wave unrecognized myocardial infarction in general population: Diagnostic value of the electrocardiogram. The REGICOR study.
abstract: BACKGROUND
  Diagnosis of unrecognized myocardial infarction (UMI) remains an open question in epidemiological and clinical studies, inhibiting effective secondary prevention of myocardial infarction. We aimed to determine the prevalence and incidence of Q-wave UMI in asymptomatic individuals aged 35 to 74years, and to ascertain the positive predictive value (PPV) of asymptomatic Q-wave to diagnose UMI.
  
  
  METHODS
  Two population-based cross-sectional studies were conducted, in 2000 (with 10-year follow-up) and in 2005. A baseline electrocardiogram was obtained for each participant. Imaging techniques (echocardiography, cardiac magnetic resonance imaging, and myocardial perfusion single-photon emission computerized tomography) were used to confirm UMI in patients with asymptomatic Q-wave.
  
  
  RESULTS
  The prevalence of confirmed Q-wave UMI in the 5580 participants was 0.18% (95% confidence interval [CI]: 0.10-0.33) and the incidence rate was 27.1 Q-wave UMI per 100,000person-years. The proportion of confirmed Q-wave UMI with respect to all prevalent MI was 8.1% (95% CI: 4.4-14.2). The PPV of asymptomatic Q-wave to diagnose Q-wave UMI was 29.2% (95% CI: 18.2-43.2%) overall, but much higher (75%, 95% CI: 40.9-92.9%) in participants with 10-year CHD risk ≥10%, compared to lower-risk participants.
  
  
  CONCLUSIONS
  Opportunistic identification of asymptomatic Q-waves by routine electrocardiogram overestimates actual Q-wave UMI, which represents 8% to 13% of all myocardial infarction in the population aged 35 to 74years. This overestimation is particularly high in the population at low cardiovascular risk. In epidemiological studies and in clinical practice, diagnosis of a pathologic Q-wave in asymptomatic patients requires detailed analysis of imaging tests to confirm or rule out myocardial necrosis.
authors.affiliation: ISV Research Group, Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Catalunya, Spain; Department of Medical Sciences, School of Medicine, University of Girona, Spain; Girona Biomedical Research Institute (IDIBGI), Catalan Institute of Health (ICS), Girona, Spain. Electronic address: rramos.girona.ics@gencat.cat.
authors.forename: Rafel
authors.initials: R
authors.lastname: Ramos
authors.affiliation: Department of Medical Sciences, School of Medicine, University of Girona, Spain; Coronary Unit and Cardiology, Hospital Josep Trueta, Girona, Biomedical Research Institute, Girona (IdIBGi), ICS, Catalunya, Spain; Doctoral Program in Public Health and Biomedical Research Methods, Autonomous University of Barcelona, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Albert
authors.affiliation: Department of Medical Sciences, School of Medicine, University of Girona, Spain; Coronary Unit and Cardiology, Hospital Josep Trueta, Girona, Biomedical Research Institute, Girona (IdIBGi), ICS, Catalunya, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Sala
authors.affiliation: ISV Research Group, Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Catalunya, Spain; Department of Medical Sciences, School of Medicine, University of Girona, Spain; Girona Biomedical Research Institute (IDIBGI), Catalan Institute of Health (ICS), Girona, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Garcia-Gil
authors.affiliation: Registre Gironí del COR (REGICOR) Group, Cardiovascular, Epidemiology and Genetics Research Group (EGEC), Municipal Institute for Medical Research (IMIM), Barcelona, Spain.
authors.forename: Roberto
authors.initials: R
authors.lastname: Elosua
authors.affiliation: Registre Gironí del COR (REGICOR) Group, Cardiovascular, Epidemiology and Genetics Research Group (EGEC), Municipal Institute for Medical Research (IMIM), Barcelona, Spain.
authors.forename: Jaume
authors.initials: J
authors.lastname: Marrugat
authors.affiliation: ISV Research Group, Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Catalunya, Spain; Girona Biomedical Research Institute (IDIBGI), Catalan Institute of Health (ICS), Girona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Ponjoan
authors.affiliation: Registre Gironí del COR (REGICOR) Group, Cardiovascular, Epidemiology and Genetics Research Group (EGEC), Municipal Institute for Medical Research (IMIM), Barcelona, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Grau
authors.affiliation: Coronary Unit and Cardiology, Hospital Josep Trueta, Girona, Biomedical Research Institute, Girona (IdIBGi), ICS, Catalunya, Spain.
authors.forename: Manel
authors.initials: M
authors.lastname: Morales
authors.affiliation: Department of Nuclear Medicine, Hospital Josep Trueta, Girona, Biomedical Research Institute, Girona (IdIBGi), ICS, Catalunya, Spain.
authors.forename: Antoni
authors.initials: A
authors.lastname: Rubió
authors.affiliation: Department of Diagnostic Radiology, Hospital Josep Trueta, Girona, Biomedical Research Institute, Girona (IdIBGi), ICS, Catalunya, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Ortuño
authors.affiliation: ISV Research Group, Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Catalunya, Spain; Girona Biomedical Research Institute (IDIBGI), Catalan Institute of Health (ICS), Girona, Spain.
authors.forename: Lia
authors.initials: L
authors.lastname: Alves-Cabratosa
authors.affiliation: ISV Research Group, Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Catalunya, Spain; Girona Biomedical Research Institute (IDIBGI), Catalan Institute of Health (ICS), Girona, Spain.
authors.forename: Ruth
authors.initials: R
authors.lastname: Martí-Lluch
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology*; D011159:Population Surveillance / Q000379:methods; D015995:Prevalence; D012042:Registries
keywords: Asymptomatic disease; Cardiac imaging techniques; ECG; Epidemiology; Myocardial infarction