Baseline predictors of pathological Q Waves and their associations with different angiographic findings in patients with ST- segment elevation myocardial infarction treated by primary percutaneous coronary intervention

Objective: Q waves on the electrocardiogram (ECG) of patients presenting with ST-segment elevation myocardial infarction (STEMI) was an independent predictor of adverse clinical outcomes. Aim of the study was to determine baseline predictors in patients who are likely to develop Q waves and their association with different angiographic findings. Methods: Standard 12-lead ECG was recorded in 262 STEMI patients treated with primary percutaneous coronary intervention (PCI). An ECG was scored as Q-wave MI according to the “classic” criteria. Demographic, clinical data, and different angiographic findings were recorded for patients who had primary PCI strategy. Results: Q waves were identified in 121 patients (46%). Both dyslipidemia and time from symptoms onset to intervention were independently and positively correlated with presence of Q wave (OR: 1.8, 95% CI 1.09 – 2.7, p = 0.04 for dyslipidemia), (OR: 1.35, 95%CI 1.09-1.67, p = 0.002 for time from symptoms onset). Patients with Q waves were more likely to have thrombus grade III - IV (OR: 1.4, 95% CI 1.10 – 1.60, p = 0.009) and TIMI flow grade < III (adjusted OR: 0.89, 95%CI 0.81 – 0.98, p=0.04). Dyslipidemia was an independent predictor for no reflow (p= 0.03). Diabetes and time from symptoms onset were independent predictors for thrombus grade III-IV (p = 0.007 and p=0.003 respectively). Conclusion: Among STEMI patients, both dyslipidemia and time from symptoms onset to intervention were independent predictors for development of Q waves. The presence of Q waves was strongly associated with heavy thrombus burden at time of intervention and TIMI flow grade < III after primary PCI.