title: Clinical significance of abnormal Q wave disappearance in acute transmural myocardial infarction.
abstract: The clinical features of acute myocardial infarction patients in whom abnormal Q wave disappeared were analyzed. Of 201 patients, 40 (20%) (Group A) showed disappearance of Q wave in serial electrocardiograms. Regional ejection fraction of the infarcted portion improved significantly (from 24 +/- 2 to 34 +/- 4%, p less than 0.001) during chronic phase in Group A, but no such improvement was present in Group B patients who showed no change in the Q wave. Global ejection fraction was greater and percent akinetic segment was smaller in Group A than in Group B at chronic phase. Coronary occlusion occurred more often at segment 7 in Group A; in Group B, occlusion occurred more frequently upstream at segment 6, suggesting Group A had a smaller area of risk. Spontaneous recanalization was more often (57%) and complete occlusion was less frequent in Group A. These indicate that Group A is characterized by a smaller area of risk, smaller infarct size, earlier reperfusion, and greater improvement in wall motion. Twenty-eight patients (70%) of Group A lost Q wave within one month and 12 patients (30%), after 3 months or more. Electrical stunning of the myocardium may be a possible mechanism for the early disappearance of Q waves, and anatomical healing for the late disappearance of Q waves.
authors.affiliation: First Department of Internal Medicine, Kinki University School of Medicine, Osaka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ishikawa
authors.forename: M
authors.initials: M
authors.lastname: Shimizu
authors.forename: M
authors.initials: M
authors.lastname: Ohno
authors.forename: M
authors.initials: M
authors.lastname: Morishita
authors.forename: I
authors.initials: I
authors.lastname: Ogawa
authors.forename: T
authors.initials: T
authors.lastname: Hayashi
authors.forename: Y
authors.initials: Y
authors.lastname: Sakaguchi
authors.forename: K
authors.initials: K
authors.lastname: Yamashita
authors.forename: H
authors.initials: H
authors.lastname: Koka
authors.forename: N
authors.initials: N
authors.lastname: Kamata
mesh_terms: D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D013318:Stroke Volume