The initial electrocardiogram pattern is a strong predictor of outcome in acute myocardial infarction

Abstract

We analyzed the significance of the initial electrocardiogram on the clinical outcome of 205 consecutive patients with a first myocardial infarction. Three different patterns of the electrocardiogram were defined: (A) Tall symmetric T waves in the involved leads; (B) ST segment elevation >0.1 mV in two or more adjacent leads; and (C) ST segment elevation together with distortion of the terminal portion of the QRS complex in two or more adjacent leads. Twelve patients were considered to have an initial ‘A’ electrocardiogram, 151 an initial ‘B’ electrocardiogram, and 42 an initial ‘C’ electrocardiogram. Four factors were significantly related to mortality: age, ST, Killip class and electrocardiographic pattern. The mortality rate was 0% in group A, 7.9% in group B, and 26.2% in group C ( P = 0.0019). Patients with type C electrocardiograms had a significantly worse Killip classification and a significantly higher sum of ST segment elevation. Among patients with inferior infarction, the mortality rate was 1.4% in type B vs. 24.1% in type C ( P = 0.0005). Among patients with anterior infarction, the mortality rate was 13% in type B vs. 30.8% in type C ( P = 0.089). We conclude that the pattern of the initial electrocardiogram is a strong predictor of outcome in acute myocardial infarction, especially if it is inferior.