title: Electrocardiographic markers of left ventricular systolic dysfunction in patients with left bundle branch block.
abstract: BACKGROUND
  Although some patients with left bundle branch block (LBBB) have structural heart diseases, some patients with LBBB have "normal hearts". The electrocardiography (ECG) criteria of LBBB in reduced left ventricular ejection fraction (LVEF) have not been defined completely.
  
  
  OBJECTIVE
  The main purpose of this study was to differentiate patients with reduced LVEF from patients with normal left ventricular systolic function simply by analysing 12-lead ECG.
  
  
  METHODS
  Subjects admitted to our hospital with LBBB in their ECG were included in the study. The patients were categorised according to their left ventricular systolic function as group 1 (LVEF ≥ 50%) and group 2 (LVEF < 50%). Duration of the QRS complex, residual conduction of left bundle branch, and concordance/discordance of T waves in leads V5, V6, or D1 were recorded. The ECG findings of the two groups were compared.
  
  
  RESULTS
  One hundred consecutive patients with LBBB were included in the study (male/female: 56/44, age: 66 ± 15 years). In the whole group, there were 35 patients with normal left ventricular systolic function (LVEF ≥ 50%), and 65 patients had LVEF below 50%. 80% of male patients with LBBB and 45% of female patients with LBBB had their LVEF below 50% (p < 0.001). Mean QRS durations of group 1 and group 2 were 132 ± 10 ms vs. 152 ± 22 ms, respectively (p < 0.001). The QRS duration of 140 ms was found to be the cut-off value to differentiate group 1 from group 2, with sensitivity and specificity of 72% and 75%, respectively. Twenty-one per cent of patients in group 1 and 69% in group 2 had discordant LBBB (p < 0.001). Residual conduction of left bundle branch was more frequent in group 2 (29% in group 1 vs. 52% in group 2, p = 0.03).
  
  
  CONCLUSIONS
  Male gender, QRS duration greater than 140 ms, discordant LBBB, and residual conduction in the left bundle branch seem to be markers of reduced LVEF in patients with LBBB.
authors.affiliation: Çukurova University, Faculty of Medicine, Adana, Turkey. alideniz78@gmail.com.
authors.forename: Ali
authors.initials: A
authors.lastname: Deniz
authors.forename: Çağlar
authors.initials: Ç
authors.lastname: Özmen
authors.forename: Halil
authors.initials: H
authors.lastname: Aktaş
authors.forename: İlayda Gül
authors.initials: İG
authors.lastname: Berk
authors.forename: Onur Sinan
authors.initials: OS
authors.lastname: Deveci
authors.forename: Çağlar Emre
authors.initials: ÇE
authors.lastname: Çağlıyan
authors.forename: Rabia
authors.initials: R
authors.lastname: Eker Akıllı
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kanadaşı
authors.forename: Mesut
authors.initials: M
authors.lastname: Demir
authors.forename: Ayhan
authors.initials: A
authors.lastname: Usal
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000175:diagnosis / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013318:Stroke Volume; D013599:Systole; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*