Prognostic significance of early q wave in the course of STEMI

During STEMI, the presence of early Q wave in infarction leads can be frequently found in clinical practice. The occurrence of an early Q wave would be associated with an increased mortality as an expression of a more extensive myocardial damage. The aim of our study was to evaluate how the presence of the Q wave at the time of the STEMI presentation correlates with infarct size, the early complications and mortality during hospital stay. Materials and Methods: From January 1st 2009 to December 31st 2014 , 248 consecutive patients with pre-hospital diagnosis of STEMI and who had primary angioplasty within 12 hours of symptom onset were transported from Emergency System to our CCU. Patients were divided into two groups based on the presence of necrosis Q wave in infarction leads at first ECG made on site of the event: group Q-wave (QWG) with 44 patients and group No Q-wave (NQWG) composed of 204 patients. For each patient demographic data, clinical variables, instrumental and laboratory examinations were collected, infarct size was evaluated according to the CPK peak value , ejection fraction ( EF) was calculated on admission , and total ischemic time (TIT) was calculated as time from symptom onset to reperfusion. Results: The QWG had a worse EF on admission to the CCU than NQWG (47% ± 17.8 vs 53.8 ± 5.9%, p = 0.00001); greater total CPK peak (3330 IU / L ± 2803.4 vs 2312 IU / L ± 2561.2, p = 0.02). The average hospital stay was significantly longer in the QWG than in NQWG (9.95 ± 7.83 vs 5.3 ± 3.2 days, 0.0013). Finally, the hospital mortality was 9% in the QWG compared to 1.9% in the NQWG (p = 0.015). The percentage of patients with a TIT≤ 120 minutes did not differ between groups (13.6% vs 21.6%, p = 0:23). At the Cox multivariate analysis age (p = 0.005), the CPK peak (p=0.03) and presence of early Q waves (p = 0.017) were independent predictors of mortality during hospital stay. Conclusions: The pathological Q wave may appear early in the acute phase of STEMI. Our data confirm that the presence of Q wave in the early stages of STEMI is a predictor of adverse clinical outcomes regardless of the duration of total ischemic time and this parameter can be used as an indicator of evolving stage of the acute myocardial infarction.