PROGNOSTIC-SIGNIFICANCE OF THE INITIAL ELECTROCARDIOGRAPHIC PATTERN IN PATIENTS WITH INFERIOR WALL ACUTE MYOCARDIAL-INFARCTION

The purpose of the study was to determine whether the initial electroc ardiographic pattern is predictive of in-hospital mortality in inferio r wall acute myocardial infarction. It is commonly perceived that pati ents with acute myocardial infarction presenting with greater ST eleva tion have a worse prognosis. The initial electrocardiogram of patients (n = 213) with inferior wall myocardial infarction was categorized ba sed on the pattern of ST-segment elevation in inferior leads: (A) ST<1 mm with tall T waves, (B) ST greater than or equal to 1 mm with norma l terminal QRS, and (C) ST greater than or equal to 1 mm with distorti on of terminal QRS. ST deviation from baseline was calculated for all leads. Patients with maximal precordial ST depression in V-4-V-6 and p attern A had an in-hospital mortality rate of 68.8% compared with 16.9 % for the entire study group. By univariate analysis, only pattern A w as significantly predictive of in-hospital mortality [odds ratio = 2.9 1, 95% confidence interval (CI) 1.22-6.93], but by multivariate analys is adjusted for (1) age, (2) diabetes mellitus, (3) previous myocardia l infarction, (4) thrombolytic therapy, (5) precordial ST-depression p attern, and (6) patterns of ST elevation, maximal ST depression in V-4 -V-6 was significantly predictive (odds ratio = 4.93, 95% CI 1.79-13.5 6), whereas pattern A was not (odds ratio = 1.12, 95% CI 0.36-3.52). C ontrary to popular perception, patients with inferior wall myocardial infarction presenting with minimal ST-segment elevation are at highest risk for in-hospital mortality, especially if accompanied by maximal precordial ST depression in V-4-V-6.