title: Left ventricular electromechanical delay in patients with heart failure and normal QRS duration and in patients with right and left bundle branch block.
abstract: OBJECTIVE
  We sought to define the reference values of intra-left ventricular (LV) electromechanical delay (EMD), and to assess the prevalence (and pattern) of intra-LV dyssynchrony in patients with heart failure (HF) and normal QRS and in patients with right and left bundle branch block.
  
  
  RESULTS
  We used tissue Doppler imaging echocardiography and a six-LV wall model to study LV EMD in 103 patients [41 with HF and normal QRS, 22 with right bundle branch block (RBBB), and 40 with left bundle branch block (LBBB)], and in 59 controls. In controls, the median intra-LV EMD was 17 ms, (inter-quartile range 13-30); 95% of controls had a value < or =41 ms. Patients showed a longer intra-LV EMD than controls: 33 ms (20-57) in patients with normal QRS, 32 ms (23-50) in RBBB patients, and 50 ms (30-94) in LBBB patients. Intra-LV dyssynchrony (defined as intra-LV EMD >41 ms) was present in 39, 36, and 60% of the patients, respectively. On average, HF patients showed the same pattern of activation as controls, from the septum to the posterior wall, but activation times were significantly prolonged. In RBBB patients the activation sequence was directed from inferior to anterior and in LBBB from anterior to inferior wall.
  
  
  CONCLUSIONS
  Left ventricular dyssynchrony was present in several patients with HF and normal QRS, and in patients with RBBB; conversely, 40% of LBBB patients showed values of LV EMD within the normal range. Left ventricular activation sequence was different between groups. Assessment of LV synchronicity by means of imaging techniques may be more important than QRS duration or morphology in selecting patients for cardiac resynchronization treatment.
authors.affiliation: Cardiology Unit, Echo-lab, Department of Cardiopulmonary Sciences, A.O. Santa Maria della Misericordia, Piazzale S. Maria della Misericordia 15, 33100 Udine, Italy. lbadan@tin.it
authors.forename: Luigi P
authors.initials: LP
authors.lastname: Badano
authors.forename: Oscar
authors.initials: O
authors.lastname: Gaddi
authors.forename: Carlo
authors.initials: C
authors.lastname: Peraldo
authors.forename: Gabriele
authors.initials: G
authors.lastname: Lupi
authors.forename: Marta
authors.initials: M
authors.lastname: Sitges
authors.forename: Frangisko
authors.initials: F
authors.lastname: Parthenakis
authors.forename: Santo
authors.initials: S
authors.lastname: Molteni
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Pagliuca
authors.forename: Biagio
authors.initials: B
authors.lastname: Sassone
authors.forename: Paola
authors.initials: P
authors.lastname: Di Stefano
authors.forename: Tiziana
authors.initials: T
authors.lastname: De Santo
authors.forename: Carlo
authors.initials: C
authors.lastname: Menozzi
authors.forename: Michele
authors.initials: M
authors.lastname: Brignole
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000503:physiopathology*; D002303:Cardiac Output, Low / Q000503:physiopathology*; D016022:Case-Control Studies; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D012016:Reference Values; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*