Predictors of inhospital outcome after acute inferior wall myocardial infarction

Introduction: Compared with anterior wall myocardial infarction, inferior wall myocardial infarction is generally regarded as being low risk. The aim of this study was to elucidate the clinical factors affecting its inhospital outcome. Methods: From January 1997 to March 2006, 546 consecutive patients who suffered from their first inferior wall myocardial infarction were recruited for the study. The demographic, clinical, electrocardiographical and angiographical characteristics, treatment and medications, complications and inhospital deaths were subjected to univariate analysis. The factors that had a p-value of less than 0.1 were included for multivariate logistic regression analysis. A p-value of less than 0.05 was considered significant. The impact of thrombolysis on clinical outcome in various high-risk patient subsets was also examined. Results: An advanced age of more than 74 years, female gender, lateral wall extension, complete atrioventricular block, bundle branch block, and cardiac free-wall rupture were found to be independent predictors of inhospital mortality, whereas the use of thrombolysis was associated with a favourable outcome. On the other hand, right ventricular infarction and precordial ST-segment depression are not predictive of poor outcome. In addition, thrombolysis reduced inhospital mortality in patients with an age above 64 years, male gender, lateral wall extension, haemodynamically-significant right ventricular infarction and complete atrioventricular block. Conclusion: In inferior wall myocardial infarction, independent predictors of poor inhospital outcome are advanced age, female gender, lateral wall extension, complete atrioventricular block, bundle branch block and cardiac free-wall rupture. The use of thrombolysis is generally beneficial, especially in those of the high-risk subsets.