Left-axis deviation in patients with nonischemic heart failure and left bundle branch block is a purely electrical phenomenon.
Computer modeling
Electrical mapping
Left bundle branch block
Left-axis deviation
QRS axis
Journal
Heart rhythm
ISSN: 1556-3871
Titre abrégé: Heart Rhythm
Pays: United States
ID NLM: 101200317
Informations de publication
Date de publication:
08 2021
08 2021
Historique:
received:
18
12
2020
revised:
19
03
2021
accepted:
30
03
2021
pubmed:
9
4
2021
medline:
12
2
2022
entrez:
8
4
2021
Statut:
ppublish
Résumé
Possible mechanisms of left-axis deviation (LAD) in the setting of left bundle branch block (LBBB) include differences in cardiac electrophysiology, structure, or anatomic axis. The purpose of this study was to clarify the mechanism(s) responsible for LAD in patients with LBBB. Twenty-nine patients with nonischemic cardiomyopathies and LBBB underwent noninvasive electrocardiographic imaging (ECGi), cardiac computed tomography, and magnetic resonance imaging in order to define ventricular electrical activation, characterize cardiac structure, and determine the cardiac anatomic axis. Sixteen patients had a normal QRS axis (NA) (mean axis 8° ± 23°), whereas 13 patients had LAD (mean axis -48° ± 13°; P <.001). Total activation times were longer in the LAD group (112 ± 25 ms vs 91 ± 14 ms; P = .01) due to delayed activation of the basal anterolateral region (107 ± 10 ms vs 81 ± 17 ms; P <.001). Left ventricular (LV) activation in patients with LAD was from apex to base, in contrast to a circumferential pattern of activation in patients with NA. Apex-to-base delay was longer in the LA group (95 ± 13 ms vs 64 ± 21 ms; P <.001) and correlated with QRS frontal axis (R LAD in LBBB appears to be due to electrophysiological abnormalities rather than structural factors or cardiac anatomic axis.
Sections du résumé
BACKGROUND
Possible mechanisms of left-axis deviation (LAD) in the setting of left bundle branch block (LBBB) include differences in cardiac electrophysiology, structure, or anatomic axis.
OBJECTIVE
The purpose of this study was to clarify the mechanism(s) responsible for LAD in patients with LBBB.
METHODS
Twenty-nine patients with nonischemic cardiomyopathies and LBBB underwent noninvasive electrocardiographic imaging (ECGi), cardiac computed tomography, and magnetic resonance imaging in order to define ventricular electrical activation, characterize cardiac structure, and determine the cardiac anatomic axis.
RESULTS
Sixteen patients had a normal QRS axis (NA) (mean axis 8° ± 23°), whereas 13 patients had LAD (mean axis -48° ± 13°; P <.001). Total activation times were longer in the LAD group (112 ± 25 ms vs 91 ± 14 ms; P = .01) due to delayed activation of the basal anterolateral region (107 ± 10 ms vs 81 ± 17 ms; P <.001). Left ventricular (LV) activation in patients with LAD was from apex to base, in contrast to a circumferential pattern of activation in patients with NA. Apex-to-base delay was longer in the LA group (95 ± 13 ms vs 64 ± 21 ms; P <.001) and correlated with QRS frontal axis (R
CONCLUSION
LAD in LBBB appears to be due to electrophysiological abnormalities rather than structural factors or cardiac anatomic axis.
Identifiants
pubmed: 33831543
pii: S1547-5271(21)00316-7
doi: 10.1016/j.hrthm.2021.03.042
pii:
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
1352-1360Informations de copyright
Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.