title: QRS duration in left bundle branch block does not affect left ventricular twisting in chronic systolic heart failure.
abstract: OBJECTIVE
  Left ventricular (LV) torsion is an important parameter of LV performance and can be influenced by several factors. Aim of this investigation was to evaluate whether QRS prolongation in left bundle branch block (LBBB) may influence global LV twist and twisting/untwisting rate in chronic systolic heart failure (HF) patients.
  
  
  METHODS
  We prospectively evaluated 30 healthy subjects (control group) and 100 chronic HF patients with severely impaired LV systolic function (ejection fraction ≤ 35%). Patients were divided into three groups according to QRS duration: A: QRS < 120 ms (n 49), B: 120 ≤ QRS ≤ 150 ms (n 28) and C: QRS > 150 ms (n 23). Patients in groups B and C presented LBBB. All subjects underwent standard trans-thoracic echocardiography and two-dimensional speckle-tracking echocardiography evaluation. Categorical variables were compared by the chi-square or the Fisher's exact test. Continuous variables were compared using the ANOVA test. Correlations between variables were analysed with linear regression.
  
  
  RESULTS
  Control subjects presented higher torsion parameters, when compared with patients in any HF group. Among the three HF groups, no differences were detected in global twist (4.79 ± 3.54, 3.8 ± 3.0 and 4.15 ± 3.14 degrees, respectively), twist rate max (44.81 ± 25.03, 37.94 ± 19.09 and 37.61 ± 24.49 degrees s(-1), respectively) and untwist rate max (-36.31 ± 30.89, -27.68 ± 34.67 and -39.62 ± 26.27 degrees s(-1), respectively) (P>0.05 for all). At linear regression analysis, there was no relation between QRS duration and any torsion parameter (P>0.05 for all).
  
  
  CONCLUSIONS
  In patients with chronic severe systolic heart failure, QRS duration and LBBB morphology do not affect LV twisting and untwisting.
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.
authors: Paola
authors: P
authors: Attanà
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.
authors: Alessandro
authors: A
authors: Paoletti Perini
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.
authors: Carmine Domenico
authors: CD
authors: Votta
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.
authors: Francesco
authors: F
authors: Cappelli
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.
authors: Paolo
authors: P
authors: Pieragnoli
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.
authors: Giuseppe
authors: G
authors: Ricciardi
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.
authors: Martina
authors: M
authors: Nesti
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.
authors: Andrea
authors: A
authors: Giomi
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.
authors: Stefania
authors: S
authors: Sacchi
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.
authors: Marco
authors: M
authors: Chiostri
authors: Dipartimento Cuore e Vasi, Università degli Studi, Firenze, Italia.|Cliniche Humanitas Gavazzeni, Bergamo, Italia.
authors: Luigi
authors: L
authors: Padeletti
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000150:complications / Q000503:physiopathology*; D002908:Chronic Disease; D004452:Echocardiography / Q000379:methods; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D054143:Heart Failure, Systolic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014102:Torsion Abnormality / Q000150:complications / Q000503:physiopathology*; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000503:physiopathology*
keywords: QRS duration; heart failure; left bundle branch block; left ventricular twist; speckle-tracking echocardiography