title: Left ventricular regional contraction abnormalities by echocardiographic speckle tracking in combined right bundle branch with left anterior fascicular block compared to left bundle branch block.
abstract: In contrast to LBBB patients less is known about patients with RBBB+LAFB regarding LV contractile abnormalities and the potential role of CRT. This study investigated whether patients with RBBB+LAFB morphology have echocardiographic mechanical strain abnormalities between the inferior and anterior LV walls, similar to abnormalities between septal and lateral walls in LBBB.
  
  
  
  Ten healthy volunteers with no-BBB, 28 LBBB and 28 RBBB+LAFB heart failure patients were included in this retrospective study. Two-dimensional regional-strains were obtained by speckle-tracking. Scar was assessed by CMR. Response on echo was defined as normal, classical, borderline or other pattern. The number of classical patterns in LBBB was significantly higher than in RBBB+LAFB and no-BBB groups (p<0.001 for both). Contrary, the RBBB+LAFB group showed a significantly higher number of borderline patterns compared to other groups (LBBB: p=0.042, no-block: p=0.012). In addition, RBBB+LAFB patients had more scar than LBBB patients (9.9% vs 3.4%, p=0.041), and the average amount of scar in each wall was also higher in RBBB+LAFB (<5% in LBBB and <16% in RBBB+LAFB).
  
  
  
  Patients with RBBB+LAFB on ECG and clinical HF demonstrate echocardiographic wall motion abnormalities between inferior and anterior LV walls, similar to abnormalities found between septal and lateral LV walls in patients with LBBB and HF. Fewer patients with RBBB+LAFB showed a classical pattern of opposing wall motion compared to LBBB. Factors that might alter strain patterns in RBBB+LAFB, including the detailed presence or absence of LV scar and coexisting block of the central fascicle, should be assessed in future studies.
authors.affiliation: Department of Cardiology, Maastricht University Medical Center, Maastricht, The Netherlands. Electronic address: ipm.leeters@student.maastrichtuniversity.nl.
authors.forename: Irene P M
authors.initials: IP
authors.lastname: Leeters
authors.affiliation: Department of Cardiology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Ashlee
authors.initials: A
authors.lastname: Davis
authors.affiliation: U.S. Food and Drug Administration, Silver Spring, MD, USA.
authors.forename: Robbert
authors.initials: R
authors.lastname: Zusterzeel
authors.affiliation: Department of Cardiology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Brett
authors.initials: B
authors.lastname: Atwater
authors.affiliation: Department of Cardiology, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Risum
authors.affiliation: Heart Centre and Clinical Institute, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Søgaard
authors.affiliation: Department of Cardiology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Igor
authors.initials: I
authors.lastname: Klem
authors.affiliation: Department of Cardiology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Robin
authors.initials: R
authors.lastname: Nijveldt
authors.affiliation: Department of Cardiology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Galen S
authors.initials: GS
authors.lastname: Wagner
authors.affiliation: Department of Cardiology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors.forename: Anton P M
authors.initials: AP
authors.lastname: Gorgels
authors.affiliation: Department of Cardiology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Kisslo
mesh_terms: D000328:Adult; D002037:Bundle-Branch Block / Q000150:complications* / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D004452:Echocardiography / Q000379:methods*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology*
keywords: Dyssynchrony; Left anterior fascicular block; Regional strain; Right bundle branch block; Speckle tracking echocardiography; Strain patterns