Prognostic importance of new small Q waves following non-ST-elevation acute coronary syndromes.
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.
Alexander
John H
JH
Duke Clinical Research Institute, Durham, North Carolina 27710, USA. alexa017@mc.duke.edu
Harrington
Robert A
RA
Bhapkar
Manju
M
Mahaffey
Kenneth W
KW
Lincoff
A Michael
AM
Ohman
E Magnus
EM
Klootwijk
Peter
P
Pahlm
Olle
O
Henden
Bo
B
Deckers
Jaap W
JW
Simoons
Maarten L
ML
Califf
Robert M
RM
Wagner
Galen S
GS
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
D000806:Angiotensin-Converting Enzyme Inhibitors; D007527:Isoenzymes; D010455:Peptides; D010975:Platelet Aggregation Inhibitors; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form; D000077542:Eptifibatide