title: Angiographic and clinical significance of 'transient' ST-segment depression in the lateral chest leads in anterior wall acute myocardial infarction.
abstract: This study aimed to clarify the significance of ST-segment depression in the lateral chest leads in anterior wall acute myocardial infarction (AMI) with ST-segment elevation. A total of 196 patients with their first anterior wall AMI (< or =6h) were divided into 2 groups according to the presence (group A, n=39) or absence (group B, n=157) of ST-segment depression > or =0.1 mV in V5 and/or V6 on the admission electrocardiogram. Patients with electrocardiographic confounding factors were excluded. No patients had persistent ST-segment depression in the lateral chest leads. Emergency coronary angiography revealed that group A had higher incidences of occlusion of the left anterior descending coronary artery (LAD) proximal to its first septal branch (77% vs 51%, p<0.01) and good collateral circulation than group B (46% vs 25%, p<0.05). Peak creatine kinase levels were significantly lower in group A than in group B (2060+/-1099 vs 2873+/-2077 IU/L, p<0.01). Left ventricular ejection fraction in the chronic phase was significantly greater in group A than in group B. Regional wall motion in the infarct region in the chronic phase was better in group A than in group B. These results indicate that patients with 'transient' ST-segment depression in the lateral chest leads in anterior wall AMI had a relatively smaller infarct size, despite their higher incidence of occlusion of the LAD proximal to its first septal branch, because of their higher incidence of good collateral circulation.
authors.affiliation: Second Department of Internal Medicine, Oita Medical University, Hasama, Oita, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Tamura
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Nagase
authors.forename: Y
authors.initials: Y
authors.lastname: Mikuriya
authors.forename: M
authors.initials: M
authors.lastname: Nasu
mesh_terms: D000368:Aged; D002637:Chest Pain; D017023:Coronary Angiography; D003327:Coronary Disease; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D011379:Prognosis; D012189:Retrospective Studies; D013909:Thorax