title: Implications of ST-segment elevation in leads V5 and V6 in patients with reperfused inferior wall acute myocardial infarction.
abstract: During inferior acute myocardial infarction, ST-segment elevation (ST↑) often occurs in leads V(5) to V(6), but its clinical implications remain unclear. We examined the admission electrocardiograms from 357 patients with a first inferior acute myocardial infarction who had Thrombolysis In Myocardial Infarction 3 flow of the right coronary artery or left circumflex artery within 6 hours after symptom onset. The patients were divided according to the presence (n = 76) or absence (n = 281) of ST↑ >2 mm in leads V(5) and V(6). Patients with ST↑ in leads V(5) and V(6) were subdivided into 2 groups according to the degree of ST↑ in leads III and V(6): ST↑ in lead III greater than in V(6) (n = 53) and ST↑ in lead III equal to or less than in V(6) (n = 23). The perfusion territory of the culprit artery was assessed using the angiographic distribution score, and a mega-artery was defined as a score of ≥0.7. ST↑ in leads V(5) and V(6) with ST↑ in lead III greater than in V(6) and ST↑ in leads V(5) and V(6) with ST↑ in lead III equal to or less than in V(6) were associated with mega-artery occlusion and impaired myocardial reperfusion, as defined by myocardial blush grade 0 to 1. Right coronary artery occlusion was most common (96%) in the former, and left circumflex artery occlusion was most common (96%) in the latter, especially proximal left circumflex occlusion (74%). Multivariate analysis showed that ST↑ in leads V(5) and V(6) with ST↑ in lead III greater than that in V(6) (odds ratio 4.81, p <0.001) and ST↑ in leads V(5) and V(6) with ST↑ in lead III equal or less than that in V(6) (odds ratio 5.96, p <0.001) were independent predictors of impaired myocardial reperfusion. In conclusion, ST↑ in leads V(5) and V(6) suggests a greater risk area and impaired myocardial reperfusion in patients with inferior acute myocardial infarction. Furthermore, comparing the degree of ST↑ in lead V(6) with that in lead III is useful for predicting the culprit artery.
authors.affiliation: The Division of Cardiology, Yokohama City University Medical Center, Yokohama, Japan. masami-kosuge@pop06.odn.ne.jp
authors.forename: Masami
authors.initials: M
authors.lastname: Kosuge
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ebina
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Hibi
authors.forename: Noriaki
authors.initials: N
authors.lastname: Iwahashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Morita
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Endo
authors.forename: Nobuhiki
authors.initials: N
authors.lastname: Maejima
authors.forename: Masaomi
authors.initials: M
authors.lastname: Gouhara
authors.forename: Zenkou
authors.initials: Z
authors.lastname: Nagashima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Umemura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kimura
mesh_terms: D017023:Coronary Angiography; D003326:Coronary Circulation / Q000502:physiology*; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D056989:Inferior Wall Myocardial Infarction / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D015425:Myocardial Reperfusion / Q000379:methods*; D011379:Prognosis; D016896:Treatment Outcome