Regression of Q Waves and Clinical Outcomes After Primary Percutaneous Coronary Intervention in St Elevation Myocardial Infarction

Abstract

Introduction: Pathological Q waves are correlated with infarct size, and Q wave regression is associated with left ventricular ejection fraction improvement. There are limited data regarding the association between Q wave regression and clinical outcomes. Our main objective was to assess the association of pathological Q wave evolution after reperfusion with clinical outcomes after ST-elevation myocardial infarction (STEMI). Patients and Methods: Standard 12-lead electrocardiograms (ECGs) were recorded in 1553 patients, who presented to our hospital with chest pain and underwent primary percutaneous coronary intervention (p-PCI) with the diagnosis of STEMI and were retrospectively analyzed. ECGs were recorded before and 90 min after PCI, as well as at hospitalization discharge and 12 months of follow-up. The study population was divided into three groups as the Q wave regression group, the Q wave persistent group, and the non-Q wave MI group. Results: There were 502 (32%) patients with persistent Q waves (PQ group), 509 (33%) patients with Q wave regression (RQ group), and 542 (35%) patients with non-Q wave MI (NQ group). The degree of LVEF was significantly greater in the RQ group and NQ group than in the PQ group [(47.5 ± 10.1 vs. 49.2 ± 9.9) vs. 43.3 ± 10.5 respectively, p<0.01]. One-year mortality was significantly greater in the PQ group compared to the RQ and NQ groups [19 (3.78%) vs. 11 (2.16%) vs. 6 (1.1%) respectively, p<0.01]. Conclusion: In a population of STEMI patients, persistent Q waves defined according to the classic ECG criteria after reperfusion were associated with high one-year mortality, and low LVEF, while Q wave regression was associated with significantly lower risk of events.