The impact of preinfarction angina on electrocardiographic ischemia grades in patients with acute myocardial infarction treated with primary percutaneous coronary intervention.

OBJECTIVE: Grade 3 ischemia (G3I) is defined as ST elevation with distortion of the terminal portion of the QRS (emergence of the J point > 50% of the R wave in leads with qR configuration, or disappearance of the S wave in leads with an Rs configuration). Patients with G3I on the presenting electrocardiogram (ECG) had worse prognosis than the patients with lesser (grade 2-G2I) ischemia. The aim of this study is to examine the effects of preinfarct angina (PIA) on electrocardiographic ischemia grades.

METHODS: One hundred forty-eight consecutive patients with ST-segment myocardial infarction (STEMI) were included in this study. All patients underwent primary percutaneous coronary intervention. The admission ECGs was analyzed retrospectively for electrocardiographic ischemia grades and compared with the presence of PIA.

RESULTS: Study population consisted of 110 patients with G2I (88 men, mean age = 63 +/- 6 years) and 38 patients with G3I (32 men, mean age = 61 +/- 8 years). Baseline characteristics of the groups were the same except for patients with G3I had significantly longer pain to balloon time and higher admission creatine kinase MB isoenzyme (CK-MB) levels. Tissue myocardial perfusion grade (TMPG) was better in patients with G2I. While 18 patients (47%) with G3I had PIA, 81 patients (70%) with G2I had PIA (P = 0.005). Although pain to balloon time and admission CK-MB were independent predictor of worse electrocardiographic ischemia grade (OR 1.69, 95% CI 1.09-2.62; P = 0.01; OR 1.01, 1.00-1.02, P = 0.04), PIA and left ventricular ejection time (LVEF) were independent predictors of better electrocardiographic ischemia grade (OR 0.4, 95% CI 0.17-0.90; P = 0.02, OR 0.92, 95% CI 0.85-0.99; P = 0.03, respectively) in multivariate logistic regression analysis.

CONCLUSION: PIA is one of the most important clinical predictors of better ischemia grades especially when combined with the pain to balloon time, LVEF, and admission CK-MB levels in patients with STEMI. This study provided another evidence for the protective effects of PIA.