Regression of ECG signs of myocardial infarction related to infarct size and left ventricular function

Abstract

Quantitative and qualitative analyses of Q waves and QRS scores were performed on 69 patients during the early phase of first myocardial infarction (MI) and 6 months subsequently. The regression of ECG signs of MI were compared with the enzymatically estimated size of MI, the location of MI, and with the changes of global ejection fraction (GEF) assessed by radionuclide ventriculography. Among 57 patients with Q wave MI a complete disappearance of ECG signs of MI was found in 9 (15.7%). Patients with MI of inferior location showed a significantly higher reduction of Q waves (p < 0.001) and QRS scores (p < 0.001) than the anterior MI group. In the group of 12 patients with non Q wave MI, 11 demonstrated complete regression of MI signs. Among all Q wave and non Q wave MIs, the authors found no significant difference in the size of MI between patients with and without complete regression of ECG signs of MI. The median of the percent of change of the QRS score was significantly higher (p = 0.04) in the group of patients with improved GEFs than in the group of patients with decreased or unchanged GEFs 6 months following acute MI. The sensitivity, specificity, and predictive values for improved left ventricular function according to the change of Q waves and ECG scores were 91%, 32%, and 62%; for changes of Q waves, 81%, 40%, and 63%; and for changes of ECG scores, 91%, 36%, and 64%, respectively. In the group of patients with non Q wave MI these values were 100%, 50%, and 91% as a result of ST-T disappearance.