Terminal QRS distortion and severity of coronary artery disease in ST-elevation myocardial infarction

Abstract

Background. Grade 3 ischemia (G3I) is defined as ST elevation with distortion of the terminal portion of the QRS complex on electrocardiograms (ECGs) of patients with ST-segment elevation myocardial infarction (STEMI). Although the association between G3I and short-and long-term cardiovascular events is well established, its mechanism is unclear. We assessed the association between G3I on the admission ECG and SYNTAX score (SS) in patients with STEMI undergoing primary percutaneous coronary intervention.

Patients and methods. The study population consisted of 312 patients with STEMI. Baseline ECGs of the patients were analyzed for grade of ischemia; the online latest updated version (2.11) of the SS calculator was used to determine the SS (http://www.syntaxscore.com). Patients were divided into two groups according to their grade of ischemia: grade 2 ischemia (G2I) or G3I. Also, patients were classified according to their SS as SS <22 (low) or SS >= 22 (high).

Results. There were 211 patients in the low SS group and 101 patients in the high SS group. G3I was present in 31.1% (n=97) of the study population. SS was significantly higher in patients with G3I than in patients with G2I (20.1 +/- 8.8 vs. 13.7 +/- 7.1, p<0.001). G3I was significantly higher in patients with high SS (50.5% vs. 21.8%, p<0.001). Multivariate logistic regression analysis revealed that G3I (p<0.001), diabetes (p=0.013), age (p=0.016), and anterior MI (p=0.011), were independent predictors of high SS.

Conclusion. In conclusion, G3I was independently related to high SS. We suggest that elevated SS in patients with G3I may explain the relationship between G3I and the poor outcome observed in these patients. Furthermore, the prediction of high SS by means of G3I in patients with STEMI may help determine the most appropriate revascularization method and prevent procedure failure.