Clinical implications and correlates of Q waves in patients with ST-elevation myocardial infarction treated with fibrinolysis: observations from the CLARITY-TIMI 28 trial.
BACKGROUND
The relationships between Q waves that appear during the acute phase of ST-elevation myocardial infarction (STEMI), clinical characteristics, ST-segment resolution (STRes), and clopidogrel therapy in patients treated with fibrinolysis are not well described.


OBJECTIVE
We hypothesized that Q waves would be associated with less successful reperfusion and increased cardiovascular events.


METHODS
In the CLARITY-TIMI 28 trial, 3491 STEMI patients treated with fibrinolysis were randomized to clopidogrel or placebo. Electrocardiograms were evaluated for STRes post-fibrinolysis and the presence of pathologic Q waves during the index hospitalization in 3322 patients.


RESULTS
Q waves were identified in 2045 patients (61.6%) prior to discharge and were associated with increased odds of congestive heart failure (CHF) (adjusted odds ratio [ORadj ]: 2.10, P = 0.002) or the composite of cardiovascular death/CHF at 30 days (ORadj : 2.08, P ≤ 0.001). Q waves were associated with lower odds of Thrombolysis in Myocardial Infarction [TIMI] flow grade 2 to 3 (ORadj : 0.78, P = 0.028), TIMI myocardial perfusion grade 3 (ORadj : 0.83, P = 0.029), and complete STRes at 90 minutes (ORadj : 0.80, P = 0.030). Patients with both a Q wave and incomplete STRes 90 minutes after fibrinolysis were at higher risk for cardiovascular death or CHF (11.1%) than patients with no Q wave and at least partial STRes (1.9%). Overall, clopidogrel tended to be equally or more effective in patients without Q waves compared to those with Q waves.


CONCLUSIONS
Among STEMI patients treated with fibrinolysis, evaluating for Q waves prior to discharge is a simple method of assessing for less successful reperfusion and an increased risk of adverse 30-day cardiovascular outcomes. The combination of Q waves and 90-minute STRes allows additional risk refinement.
TIMI Study Group, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
Jonathan W
JW
Waks
Marc S
MS
Sabatine
Christopher P
CP
Cannon
David A
DA
Morrow
C Michael
CM
Gibson
Stephen D
SD
Wiviott
Robert P
RP
Giugliano
Sarah
S
Sloan
Benjamin M
BM
Scirica
D000368:Aged; D001241:Aspirin / Q000627:therapeutic use; D000077144:Clopidogrel; D017023:Coronary Angiography; D003326:Coronary Circulation; D003328:Coronary Thrombosis / Q000000981:diagnostic imaging; D052279:Creatine Kinase, MB Form / Q000097:blood; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000453:epidemiology*; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000401:mortality*; D015425:Myocardial Reperfusion / Q000379:methods*; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D011379:Prognosis; D018570:Risk Assessment / Q000379:methods; D012737:Sex Factors; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000627:therapeutic use
D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D052279:Creatine Kinase, MB Form; D013988:Ticlopidine; D001241:Aspirin