Abstract

Waks, J. W., Sabatine, M. S., Cannon, C. P., Morrow, D. A., Gibson, C. M., Wiviott, S. D., Giugliano, R. P., Sloan, S., Scirica, B. M. Clinical Implications and Correlates of Q Waves in Patients With ST-Elevation Myocardial Infarction Treated With Fibrinolysis: Observations from the CLARITY-TIMI 28 Trial Clin Cardiol. 2014;37(3):160-6.

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. HYPOTHESIS: 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.

Trial: CLARITY-TIMI 28