title: Clinical implications of intermediate QRS prolongation in the absence of bundle-branch block in patients with ST-segment-elevation acute myocardial infarction.
abstract: BACKGROUND
  In the reperfusion era the clinical characteristics of intermediate QRS prolongation without bundle-branch block (BBB) remain unclear in patients with ST-segment elevation myocardial infarction (STEMI).
  
  
  RESULTS
  A total of 465 patients with STEMI within 24 h of onset were classified into 3 groups according to QRS duration on presenting electrocardiograms: 338 patients had QRS duration <100 ms (group N), 71 had QRS duration >or=100 ms without BBB (group W), and 56 had BBB (group B). The frequency of Killip class >1 was higher in group W (28%) than in group N (12%), but lower than in group B (47%) (p<0.05, respectively). The percentages of patients with non-anterior infarction (69% vs 42%, 47%), 3-vessel disease (30% vs 9%, 16%), and coronary artery bypass graft surgery (24% vs 4%, 13%) were higher in group W than in groups N and B (all p<0.05). In group W, 6-month-mortality was similar to that in group N, but lower than that in group B (4%, 3% vs 25%, p<0.05 respectively).
  
  
  CONCLUSIONS
  In the reperfusion era, although patients with intermediate QRS prolongation without BBB have more severe coronary disease, 6-month-mortality is similar to those with normal conduction, but lower than those with BBB.
authors.affiliation: Division of Cardiology, Yokohama City University Medical Center, Yokohama, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Tsukahara
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kimura
authors.forename: Masami
authors.initials: M
authors.lastname: Kosuge
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Shimizu
authors.forename: Teruyasu
authors.initials: T
authors.lastname: Sugano
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Hibi
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kanna
authors.forename: Noritaka
authors.initials: N
authors.lastname: Toda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Takamura
authors.forename: Jun
authors.initials: J
authors.lastname: Okuda
authors.forename: Naoki
authors.initials: N
authors.lastname: Nozawa
authors.forename: Eri
authors.initials: E
authors.lastname: Furukawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Umemura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D002037:Bundle-Branch Block; D002637:Chest Pain / Q000503:physiopathology; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000502:physiology*; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000453:epidemiology; D006801:Humans; D007022:Hypotension / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy; D012189:Retrospective Studies; D016019:Survival Analysis