The Relationship between Q-wave Regression and Improvement in the Left Ventricular Systolic Function after an Anterior Wall Acute Myocardial Infarction

ABSTRACT

BACKGROUND AND OBJECTIVES: An abnormal Q wave, after an acute myocardial infarction, has been considered an indicator of myocardial necrosis. However, in some cases this Q wave partially or completely disappears during the evolution of the myocardial infarction. The clinical significance of Q wave regression remains to be established. Accordingly, this study was conducted to evaluate the relationship between Q wave regression, after an anterior wall acute myocardial infarction, and the improvements of the regional wall motion abnormality and left ventricular ejection fraction in echocardiography. SUBJCETS AND METHODS: A total of 80 patients, who presented with a first anterior wall acute myocardial infarction, managed successfully with direct intervention, were divided into two groups according to the regression (group A) or presence (group B) of abnormal Q waves. Regression of an abnormal Q wave was defined as the disappearance of the Q wave and reappearance of the R wave > or =0.1 mV, in at least two of the I, aVL, and V1 to V6 leads. RESULTS: Of the 80 patients, 26 (32.5 %) had an abnormal Q wave regression within 12 months. The peak creatine kinase-MB activity was lower in group A than B (277.3+/-202.6 vs. 521.3+/-284.4 ng/dL, pc<0.01). Group A had better left ventricular regional wall motion than group B in the initial echocardiograms. The degree of improvement of the left ventricular ejection fraction and regional wall motion between the initial and follow-up echocardiographies were significantly greater in group A than B. CONCLUSION: Patients with an anterior wall acute myocardial infarction, showing Q wave regression, tended towards a smaller amount of necrotic myocardium and a significantly larger amount of stunned myocardium.