title: Minor isolated Q waves and cardiovascular events in the MESA study.
abstract: BACKGROUND
  The significance of minor isolated Q waves in the resting electrocardiograms (ECGs) of apparently healthy individuals is unknown.
  
  
  OBJECTIVE
  To examine the association between minor isolated Q waves and incident cardiovascular disease events in the Multi-Ethnic Study of Atherosclerosis (MESA).
  
  
  METHODS
  This analysis included 6551 MESA participants (38% white, 28% black, 22% Hispanic, 12% Chinese) who were free of cardiovascular disease at enrollment. Cox proportional hazards models were used to examine the association between minor isolated Q waves defined by the Minnesota ECG Classification with adjudicated incident cardiovascular events.
  
  
  RESULTS
  During up to 7.8 years of follow-up, 423 events occurred, with a rate of 10.7 events per 1000 person-years. A significant interaction between minor isolated Q waves and race/ethnicity was observed (P=.030). In models stratified by race/ethnicity and adjusted for demographics, socioeconomic status, common cardiovascular risk factors, and other ECG abnormalities, presence of isolated minor Q waves was significantly associated with incident cardiovascular events in Hispanics (hazard ratio [HR] 2.62; 95% confidence interval [CI], 1.42-4.82), but not in whites (HR 0.65; 95% CI, 0.32-1.33) or blacks (HR 1.46; 95% CI, 0.74-2.89). Despite the statistically significant association in the Chinese population, the small number of events precluded solid conclusions in this race/ethnicity.
  
  
  CONCLUSIONS
  The prognostic significance of minor isolated Q waves varies across races/ethnicities; they carry a high risk for future cardiovascular events in apparently healthy Hispanics, but not in whites or blacks.
authors.affiliation: Epidemiological Cardiology Research Center (EPICARE), Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: Yabing
authors.initials: Y
authors.lastname: Li
authors.forename: Farah Z
authors.initials: FZ
authors.lastname: Dawood
authors.forename: Haiying
authors.initials: H
authors.lastname: Chen
authors.forename: Aditya
authors.initials: A
authors.lastname: Jain
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Walsh
authors.forename: Alvaro
authors.initials: A
authors.lastname: Alonso
authors.forename: Donald M
authors.initials: DM
authors.lastname: Lloyd-Jones
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D050197:Atherosclerosis / Q000208:ethnology*; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000208:ethnology; D004562:Electrocardiography; D005006:Ethnicity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors