title: Prognostic importance of new small Q waves following non-ST-elevation acute coronary syndromes.
abstract: OBJECTIVE
  To investigate the prognostic importance of new small Q waves following an acute coronary syndrome.
  
  
  METHODS
  We assessed 6-month mortality in 10501 patients with non-ST-elevation acute coronary syndromes who had survived 30 days and had both admission and 30-day electrocardiograms. Patients were stratified by whether they had no new Q waves (n = 9447), new 30- to 40-ms Q waves (n = 733), or new > or =40-ms Q waves (n = 321).
  
  
  RESULTS
  Mortality was higher in patients with 30- to 40-ms Q waves than in those with no new Q waves (3.4% [25/733] vs. 2.4% [227/9447], P = 0.005), and even higher in those with > or =40-ms Q waves (5.3% [17/321], P = 0.002). After adjustment for baseline risk predictors, mortality remained higher in patients with new 30- to 40-ms Q waves (odds ratio [OR] = 1.30; 95% confidence interval [CI]: 0.85 to 1.98; P = 0.23) and those with new > or =40-ms Q waves (OR = 1.87; 95% CI: 1.13 to 3.09; P = 0.01).
  
  
  CONCLUSIONS
  Patients with new small Q waves following a non-ST-elevation acute coronary syndrome are at increased risk of adverse outcomes. These small Q waves should be considered diagnostic of myocardial infarction. Further research should investigate whether even smaller QRS changes are prognostically important.
authors.affiliation: Duke Clinical Research Institute, Durham, North Carolina 27710, USA. alexa017@mc.duke.edu
authors.forename: John H
authors.initials: JH
authors.lastname: Alexander
authors.forename: Robert A
authors.initials: RA
authors.lastname: Harrington
authors.forename: Manju
authors.initials: M
authors.lastname: Bhapkar
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Mahaffey
authors.forename: A Michael
authors.initials: AM
authors.lastname: Lincoff
authors.forename: E Magnus
authors.initials: EM
authors.lastname: Ohman
authors.forename: Peter
authors.initials: P
authors.lastname: Klootwijk
authors.forename: Olle
authors.initials: O
authors.lastname: Pahlm
authors.forename: Bo
authors.initials: B
authors.lastname: Henden
authors.forename: Jaap W
authors.initials: JW
authors.lastname: Deckers
authors.forename: Maarten L
authors.initials: ML
authors.lastname: Simoons
authors.forename: Robert M
authors.initials: RM
authors.lastname: Califf
authors.forename: Galen S
authors.initials: GS
authors.lastname: Wagner
mesh_terms: D000208:Acute Disease; D000368:Aged; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use; D016001:Confidence Intervals; D017023:Coronary Angiography / Q000706:statistics & numerical data; D003327:Coronary Disease / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality* / Q000628:therapy; D003402:Creatine Kinase / Q000032:analysis; D052279:Creatine Kinase, MB Form; D004562:Electrocardiography; D000077542:Eptifibatide; D005260:Female; D006333:Heart Failure / Q000401:mortality; D006801:Humans; D007527:Isoenzymes / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality* / Q000628:therapy; D009204:Myocardial Revascularization / Q000706:statistics & numerical data; D016017:Odds Ratio; D010455:Peptides / Q000627:therapeutic use; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D011379:Prognosis; D016019:Survival Analysis; D015996:Survival Rate; D013577:Syndrome; D018487:Ventricular Dysfunction, Left / Q000401:mortality
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D007527:Isoenzymes; D010455:Peptides; D010975:Platelet Aggregation Inhibitors; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form; D000077542:Eptifibatide