Stimulation and propagation of activation in conduction tissue: Implications for left bundle branch area pacing.
Conduction block
Conduction slowing
Fascicular block
His bundle
Left bundle
Left bundle branch area pacing
Left bundle branch block
Strength-duration curve
Journal
Heart rhythm
ISSN: 1556-3871
Titre abrégé: Heart Rhythm
Pays: United States
ID NLM: 101200317
Informations de publication
Date de publication:
05 2021
05 2021
Historique:
received:
27
07
2020
revised:
23
12
2020
accepted:
30
12
2020
pubmed:
9
1
2021
medline:
19
1
2022
entrez:
8
1
2021
Statut:
ppublish
Résumé
Characterizing wavefront generation and impulse conduction in left bundle (LB) has implications for left bundle branch area pacing (LBBAP). The purpose of this study was to describe the pacing characteristics of LB and to study the role of pacing pulse width (PW) in overcoming left bundle branch block. Twenty fresh ovine heart slabs containing well-developed and easily identifiable tissues of the conduction system were used for the study. LB stimulation, activation, and propagation were studied under baseline conditions, simulated conduction slowing, conduction block, and fascicular block. The maximum radius of the LB early activation increased up to 13.4 ± 2.4 mm from the pacing stimulus, and the time from stimulus to evoked potential shortened when pacing PW was increased from 0.13 to 2 ms at baseline. Conduction slowing and block induced by cooling could be resolved by increasing pacing PW from 0.25 to 1.5 ms over a distance of 10 ± 1.5 mm from the pacing stimulus. The LB strength-duration (SD) curve was shifted to the left of the myocardial SD curve. Increasing PW resolved conduction slowing and block and bypassed the experimental model of fascicular block in LB. Precise positioning of the LB lead in left ventricular subendocardium is not mandatory in LBBAP, as the SD curve of LB was shifted to the left of the myocardium SD curve and could be captured from a distance by optimizing PW.
Sections du résumé
BACKGROUND
Characterizing wavefront generation and impulse conduction in left bundle (LB) has implications for left bundle branch area pacing (LBBAP).
OBJECTIVES
The purpose of this study was to describe the pacing characteristics of LB and to study the role of pacing pulse width (PW) in overcoming left bundle branch block.
METHODS
Twenty fresh ovine heart slabs containing well-developed and easily identifiable tissues of the conduction system were used for the study. LB stimulation, activation, and propagation were studied under baseline conditions, simulated conduction slowing, conduction block, and fascicular block.
RESULTS
The maximum radius of the LB early activation increased up to 13.4 ± 2.4 mm from the pacing stimulus, and the time from stimulus to evoked potential shortened when pacing PW was increased from 0.13 to 2 ms at baseline. Conduction slowing and block induced by cooling could be resolved by increasing pacing PW from 0.25 to 1.5 ms over a distance of 10 ± 1.5 mm from the pacing stimulus. The LB strength-duration (SD) curve was shifted to the left of the myocardial SD curve.
CONCLUSION
Increasing PW resolved conduction slowing and block and bypassed the experimental model of fascicular block in LB. Precise positioning of the LB lead in left ventricular subendocardium is not mandatory in LBBAP, as the SD curve of LB was shifted to the left of the myocardium SD curve and could be captured from a distance by optimizing PW.
Identifiants
pubmed: 33418128
pii: S1547-5271(20)31225-X
doi: 10.1016/j.hrthm.2020.12.030
pii:
doi:
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
813-821Subventions
Organisme : CIHR
ID : MOP 142272
Pays : Canada
Commentaires et corrections
Type : CommentIn
Informations de copyright
Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.