Prognosis and first diagnostic ECG in STEMI patients referred to the emergency medical system for primary PCI

Pathological Q waves (QWs) in the first ECG recorded at hospital admission has been found to correlate with myocardial damage and mortality in STEMI patients. We investigated the association between new QWs recorded in the pre-hospital setting and adverse outcome during the hospital stay. A pre-hospital ECG was recorded in 248 patients with STEMI who underwent primary PCI. Patients were divided into two groups based on the presence (n = 44, QWs) or absence (n = 204, non-QWs) of new QWs. Patients with new QWs had a higher prevalence of anterior infarct, cardiogenic shock and a lower LV ejection fraction. In-hospital mortality was higher in patients with new QWs. The percentage of patients with new QWs increased progressively with increasing pain to ECG time. New QWs provide rapid prognostic information in the pre-hospital phase of STEMI by identifying patients at risk of adverse outcome during the hospital stay. •Pathologic Q waves in the first ECG in STEMI patients increased progressively with increasing pain to ECG time.•Patients with Q waves had a larger myocardial infarction and a lower LV ejection fraction.•In-hospital mortality was higher in patients with Q waves than in patients without Q waves.•Presence of Q waves in the first diagnostic ECG (HR 10, 95% CI 1.5-66, p = 0.017) was an independent predictor of intra-hospital mortality.