Pathological Q waves in myocardial infarction in patients treated by primary PCI
JACC: Cardiovascular Imaging , Volume 6 - Issue 3 p. 324- 331
Objectives: In the present study, we investigated the association of pathological Q waves with infarct size. Furthermore, we investigated whether Q-wave regression was associated with improvement of left ventricular ejection fraction (LVEF), infarct size, and left ventricular dimensions in ST-segment elevation myocardial infarction (STEMI) patients with early Q-wave formation compared with patients without or persistent pathological Q waves. Background: The criteria for pathological Q waves after acute myocardial infarction (MI) have changed over the years. Also, there are limited data regarding correlation of Q-wave regression and preservation of LVEF in patients with an initial Q-wave MI. Methods: Standard 12-lead electrocardiograms (ECGs) were recorded in 184 STEMI patients treated with primary percutaneous coronary intervention (PCI). ECGs were recorded before and following PCI, as well as at 1, 4, 12, and 24 months of follow-up. An ECG was scored as Q-wave MI when it showed Q waves in 2 or more contiguous leads according to the 4 readily available clinical definitions used over the years: "classic" criteria, Thrombolysis In Myocardial Infarction criteria, and 2000 and 2007 consensus criteria. Cardiac magnetic resonance (CMR) examination was performed at 4 ± 2 days after reperfusion and repeated after 4 and 24 months. Contrast-enhanced CMR was performed at baseline and 4 months. Results: The classic ECG criteria showed strongest correlation with infarct size as measured by CMR. The incidence of Q-wave MI according to the classic criteria was 23% 1 h after PCI. At 24 months of follow-up, 40% of patients with initial Q-wave MI displayed Q-wave regression. Patients with a Q-wave MI had larger infarct size and lower LVEF on baseline CMR (24 ± 10% LV mass and 37 ± 8%, respectively) compared with patients with non-Q-wave MI (17 ± 9% LV mass, p < 0.01, and 45 ± 8%, p < 0.001, respectively). Patients with Q-wave regression displayed significantly larger LVEF improvement in 24 months (9 ± 11%) as compared with both persistent Q-wave MI (2 ± 8%) as well as non-Q-wave MI (3 ± 8%, p = 0.04 for both comparisons). Conclusions: Association of Q waves with infarct size is strongest when using the classic Q-wave criteria. Q-wave regression is associated with the largest improvement of LVEF as assessed with CMR.
|cardiac magnetic resonance, myocardial infarction, Q waves|
|JACC: Cardiovascular Imaging|
|Organisation||Department of Cardiology|
Delewi, R, Ijff, G, van de Hoef, T.P, Hirsch, A, Robbers, L.F.H.J, Nijveldt, R, … Piek, J.J. (2013). Pathological Q waves in myocardial infarction in patients treated by primary PCI. JACC: Cardiovascular Imaging, 6(3), 324–331. doi:10.1016/j.jcmg.2012.08.018