Simulation study of electrotonic coupling between human atrial myocytes and mechanosensitive fibroblasts

This study aimed to investigate the effect on adjacent myocyte of fibroblasts (Fbs) with the incorporation of mechano-gated currents induced by mechanical compression (l
_ci
) of cardiac Fbs. The human atrial myocyte (hAM) was modeled by the Courtemanche-Ramirez-Nattel model. With two different experimentally observed Fbs compression (2 μm and 3 μm), l
_ci
was numerically simulated as l
_cil
and l
_cih
. They were then incorporated into two types of electrophysiological models of human atrial Fbs: passive and active models, respectively. In both passive and active models, l
_ci
depolarized the membrane potential of cardiac Fbs. When coupled with passive Fbs, the action potential of myocyte duration at 90% (APD
₉₀
) was increased in comparison with uncoupled hAM. With the incorporation of I
_ci
into passive Fbs, APD
₉₀
of myocyte was further increased. When coupled with active Fbs, similar increases were obtained with the incorporation of both l
_ci
Furthermore, the resting potential and the maximum value of the action potential of hAM were also increased for both models and with both I
_ci
. The preliminary simulation study confirmed that mechanosentitive currents in fibroblasts play an important role in mechano-electrical coupling.