Uncertain meaning of early Q-wave in STEMI. Can we still rely on its relevance?

Abstract

Abstract Background In patients with a first STEMI treated with invasive reperfusion strategy, early Q-waves do not predict a poor prognosis. The presence of a Q wave, although the common clinical misconception of its association with irreversible myocardial necrosis, should not necessarily change the reperfusion strategy, but hasten it. Purpose We aimed to examine if early Q-waves in patients in the emergency department of a tertiary center in the first 6 hours of chest pain, were associated with base demographics, in-hospital mortality, major adverse cardiovascular events, cardiac biomarkers, and cardiac imaging. Methods Retrospective cohort study of 1012 patients of which 251 had early Q-waves on their 12-lead ECG during the first 6 hours of chest pain. Q-waves were defined by the criteria of the Fourth Universal Definition of Myocardial Infarction. The cohort were the patients with Q-waves in ECG and compared each variable with its due statistical test. Results We found that age (54 vs 54, p=0.393), BMI (27.3 vs 27.4, p=0.683), diabetes (63 vs 196, p=0.266), smoking (118 vs 278, p=0.09), dyslipidemia (84 vs 195, p=0.152), hypertension (98 vs 258, p=0,747) and previous stroke (2 vs 10, p=0.42) were not associated with the presence of early Q-waves in our population. There were no statistically significant differences within groups in global mortality (6% vs 14%, p=0.754), neither in cardiogenic shock (7% vs 15%, p =0.754), acute heart failure (8% vs 15%, p=0.390), acute pulmonary edema (2% vs 7%, p=0.749), stroke (0% vs 3%, p=0.292), atrial fibrillation and flutter (8% vs 12%, p=0.183), high degree AV block (15% vs 29%, p=0.273), ventricular tachycardia and fibrillation (18% vs 41%, p=0.522) and mayor bleeding (2% vs 3%, p=0.509). Heart rate at admission was higher (p<0.05) as well as the first determination of CK-MB (11.84 vs 8.48, p<0.05). Interestingly, Q-waves were associated with greater likelihood of coronary occlusions, with a TIMI grade 0 before intervention (184 vs 458, p=0.044). There were no differences in reduced left ventricle ejection fraction (60.21 vs 60.96, p=0.06) or microvascular disease (76.38 vs 76.53, p=0.96) in cardiac magnetic resonance. Conclusions The presence of Q-wave at 6 first hours of chest pain was associated with higher cardiac biomarker expression and a greater incidence of coronary artery occlusion on cardiac catheterization. Early PCI should be directed as a first option to this group of patients, and this evidence might aim to perform it beyond the established 12-hour cutoff time.