Improvement of Cardiac Function in Patients With and Without Disappearance of Abnormal Q waves After Inferior Myocardial Infarction

In some patients with Q wave myocardial infarction (MI), abnormal Q waves disappear during the chronic phase. Previous studies reported that Q-wave regression indicates a smaller infarct size and good left ventricular (LV) function in patients with anterior MI. However, many of these reports describe patients with anterior MI, and there are no reports limited to patients with inferior MI. This study aimed to evaluate the relationship between the disappearance of abnormal Q waves in the inferior electrocardiographic leads (leads II, III, and aVF) and LV function in patients with inferior MI, and clarify the clinical significance of the disappearance of abnormal Q waves in inferior MI.<br>The subjects were 184 patients with first acute Q-wave inferior MI. These 184 subjects included 20 patients with disappearance of abnormal Q waves in leads II, III, and aVF (Group Q (-)), 37 with disappearance of abnormal Q waves in 2 leads (leads II and aVF) (Group Q (+) I), 70 with disappearance of abnormal Q waves in only 1 lead (lead aVF) (Group Q (+) II), and 57 with persistent abnormal Q waves in 3 leads (leads II, III, and aVF) (Group Q (+) III) in electrocardiography 1 year after the onset of MI. In the groups with disappearance of abnormal Q waves, echocardiography showed a significant improvement in the inferior regional wall motion index (Inf-WMI) between the acute phase and 1 year after the onset of MI (p < 0.001), and myocardial viability was recognized. The number of patients with an improvement of LV wall motion normally within 1 year after the onset of MI was 7 (35%) in the Group Q (-) and 8 (22%) in the Group Q (+) I, showing high rates compared with the Group Q (+) III (0: (p < 0.001). In the group with disappearance of abnormal Q waves within 1 year after the onset of the inferior MI, Inf-WMI in the chronic phase and the total defect score by SPECT were significantly smaller, and LV ejection fraction onset 1 year later was significantly higher (p < 0.001) compared to the Group Q (+) III with persistent abnormal Q waves. In the patients with disappearance of abnormal Q waves of the inferior leads, myocardial viability was present, with small-sized infarcts and good LV systolic function. In particular, the patients with a large number of leads with disappearance of abnormal Q waves showed greater improvement of Inf-WMI and more favorable LV ejection fraction.<br>In conclusion, the presence or absence of abnormal Q waves, and the number of leads with abnormal Q wave disappearance were indicators for improvement of LV function in the chronic phase.