title: Evaluation of global left ventricular function and mechanical dyssynchrony in patients with an asymptomatic left bundle branch block: a real-time 3D echocardiography study.
abstract: BACKGROUND
  A left bundle branch block (LBBB) affects both global left ventricular (LV) function and mechanical dyssynchrony. The aim was to evaluate global LV function and mechanical dyssynchrony with real-time 3D echocardiography (RT3DE), in asymptomatic LBBB patients, healthy volunteers and patients with symptomatic heart failure (HF) and a LBBB. Furthermore, the relation between presence or absence of symptoms of HF and mechanical dyssynchrony was investigated.
  
  
  METHODS
  RT3DE was performed in 61 consecutive patients: 16 healthy volunteers, 22 patients with an asymptomatic LBBB and 23 patients with symptomatic HF and a LBBB. Global LV function and the systolic dyssynchrony index (SDI) were measured.
  
  
  RESULTS
  In healthy volunteers, mean LV ejection fraction was 54 +/- 5%, in asymptomatic LBBB patients 50 +/- 9%, and in HF patients 29 +/- 9%. SDI was 5.6 +/- 3.6%, 7.3 +/- 3.2% and 12.8 +/- 4.8% for healthy volunteers, asymptomatic LBBB patients and HF patients respectively. SDI differed significantly between HF patients and both other groups. A cut-off value for SDI for presence of symptoms of HF was 10.8%.
  
  
  CONCLUSIONS
  Asymptomatic LBBB patients have more depressed global LV function than healthy volunteers have; patients with symptoms of HF and a LBBB have severe global LV dysfunction. Asymptomatic LBBB patients have an intermediate mechanical dyssynchrony; HF patients with a LBBB have the most severe mechanical dyssynchrony. A substantial amount of mechanical dyssynchrony might be accompanied by the presence of symptoms of HF.
authors: Department of Cardiology ZH 6D 120, VU University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands. jeroen.vandijk@vumc.nl
authors: Jeroen
authors: J
authors: van Dijk
authors: Pieter A
authors: PA
authors: Dijkmans
authors: Marco J W
authors: MJ
authors: Götte
authors: Marieke D
authors: MD
authors: Spreeuwenberg
authors: Cees A
authors: CA
authors: Visser
authors: Otto
authors: O
authors: Kamp
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D016022:Case-Control Studies; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D015203:Reproducibility of Results; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology*