Effect of heterogeneities in the cellular microstructure on propagation of the cardiac action potential.
Med Biol Eng Comput
; 50(8): 813-25, 2012 Aug.
Article
em En
| MEDLINE
| ID: mdl-22729348
ABSTRACT
Cardiac arrhythmias are initiated in regions that undergo cellular remodeling as a result of disease. Using a sub-cellular model of myocardium, we studied the mechanism of block caused by tissue microstructure remodeling cell geometry [quantified as length/width (L/W) cell ratio] and cell-to-cell coupling (G(j)). Heterogeneities in cell L/W ratio and G ( j ) lead to block when excitability is reduced and the corresponding space constant λ (in the direction of propagation) increases by >40 %. Tissue architectures with elongated cells (i.e. large cell L/W ratios) that are better coupled (i.e. large G(j)) are less prone to block at sites of regional heterogeneities in cell geometry and/or cell coupling than tissue architectures consisting of cells with smaller L/W ratios and/or poorer coupling. Whether an increase in tissue anisotropic ratio (ANR) is arrhythmogenic or not depends on the cellular mechanism of the increase ANR leads to an increased risk of block when G(j) decreases, but to a decreased risk of block when cell L/W ratio increases. Our findings are useful to understand the mechanisms of block in cardiac pathologies that result in tissue architecture remodeling.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Potenciais de Ação
/
Transmissão Sináptica
/
Miócitos Cardíacos
/
Bloqueio Cardíaco
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Sistema de Condução Cardíaco
/
Modelos Cardiovasculares
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article