Antecedent angina pectoris as a predictor of better functional and clinical outcomes in patients with an interior wall acute myocardial infarction

We examined whether angina pectoris (AP) occurring shortly before the onset of acute myocardial infarction (AMI) can render the right ventricle and th e conducting tissue resistant to ischemia in 75 patients with an inferior w all AMI. Each patient had total occlusion in the proximal right coronary ar tery and underwent successful coronary angioplasty less than or equal to 24 hours from the onset. We divided patients into 2 groups based on presence or absence of antecedent AP less than or equal to 24 hours before the syste m onset: group 1 (absent) = 57 patients; group 2 (present) 18 patients. Col lateral circulation was more frequently observed in group 2 than in group 1 (group 1 vs 2, 28% vs 61%, p < 0.01). Elevation in ST segment greater than or equal to 1 mm in lead V-4R, hemodynamic right ventricular dysfunction, and Frequency of high-degree heart block were more frequent in group 1 than in group 2 (75% vs 44%, 79% vs 39%, 53% vs 11%, p < 0.05, respectively). M ultivariate analysis demonstrated that antecedent AP is the only factor rel ated to these complications. Thus, episodes of AP occurring shortly before onset may restrain development of ischemic damage of the right ventricle an d conducting tissue, and are associated with better clinical and functional outcomes among patients with an inferior wall AMI. (C) 1999 by Excerpta Me dica, Inc.