Limits...
Conditions for Waveblock Due to Anisotropy in a Model of Human Ventricular Tissue.

Kudryashova NN, Kazbanov IV, Panfilov AV, Agladze KI - PLoS ONE (2015)

Bottom Line: We have examined the border between different areas of myocardial fiber alignment and have shown that blockage can occur for a wave traveling from a transverse fiber area to a longitudinal one.Such blockage occurs for reasonable values of the anisotropy ratio (AR): from 2.4 to 6.2 with respect to propagation velocities.Hyperkalemia affects the block formation in a complex, biphasic way.

View Article: PubMed Central - PubMed

Affiliation: Life Science Center, Moscow Institute of Physics and Technology, Dolgoprudny, Russia; Department of Physics and Astronomy, Ghent University, Ghent, Belgium.

ABSTRACT
Waveblock formation is the main cause of reentry. We have performed a comprehensive numerical modeling study of block formation due to anisotropy in Ten Tusscher and Panfilov (2006) ionic model for human ventricular tissue. We have examined the border between different areas of myocardial fiber alignment and have shown that blockage can occur for a wave traveling from a transverse fiber area to a longitudinal one. Such blockage occurs for reasonable values of the anisotropy ratio (AR): from 2.4 to 6.2 with respect to propagation velocities. This critical AR decreases by the suppression of INa and ICa, slightly decreases by the suppression of IKr and IKs, and substantially increases by the suppression of IK1. Hyperkalemia affects the block formation in a complex, biphasic way. We provide examples of reentry formation due to the studied effects and have concluded that the suppression of IK1 should be the most effective way to prevent waveblock at the areas of abrupt change in anisotropy.

No MeSH data available.


Related in: MedlinePlus

Conditions for waveblock formation in hyperkalemia.a) The dependence of the critical period of stimulation on the AR for various potassium concentrations outside of the cell [K+]o. The blue line shows the critical period of stimulation under normal conditions ([K+]o = 5.4 mM). b) The dependence of the critical AR on potassium concentration outside of the cell [K+]o for various stimulation frequencies.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4629901&req=5

pone.0141832.g007: Conditions for waveblock formation in hyperkalemia.a) The dependence of the critical period of stimulation on the AR for various potassium concentrations outside of the cell [K+]o. The blue line shows the critical period of stimulation under normal conditions ([K+]o = 5.4 mM). b) The dependence of the critical AR on potassium concentration outside of the cell [K+]o for various stimulation frequencies.

Mentions: Finally, we studied the effect of hyperkalemia (Fig 7), one of the most important consequences of ischemia. Since most cardiac arrhythmias occur under ischemic conditions, the influence of such conditions on block formation is important. We have found that an increase of the extracellular K+ concentration results in a complex, nonmonotonous change in critical anisotropies (Fig 7a). Before we analyze the curves shown in this figure, let us consider a more simple representation, shown in Fig 7b, which illustrates the dependency of the critical AR vs. potassium concentration ([K+]o) for several stimulation frequencies. (0.5 Hz, 1 Hz, 2 Hz and 2.5 Hz).


Conditions for Waveblock Due to Anisotropy in a Model of Human Ventricular Tissue.

Kudryashova NN, Kazbanov IV, Panfilov AV, Agladze KI - PLoS ONE (2015)

Conditions for waveblock formation in hyperkalemia.a) The dependence of the critical period of stimulation on the AR for various potassium concentrations outside of the cell [K+]o. The blue line shows the critical period of stimulation under normal conditions ([K+]o = 5.4 mM). b) The dependence of the critical AR on potassium concentration outside of the cell [K+]o for various stimulation frequencies.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4629901&req=5

pone.0141832.g007: Conditions for waveblock formation in hyperkalemia.a) The dependence of the critical period of stimulation on the AR for various potassium concentrations outside of the cell [K+]o. The blue line shows the critical period of stimulation under normal conditions ([K+]o = 5.4 mM). b) The dependence of the critical AR on potassium concentration outside of the cell [K+]o for various stimulation frequencies.
Mentions: Finally, we studied the effect of hyperkalemia (Fig 7), one of the most important consequences of ischemia. Since most cardiac arrhythmias occur under ischemic conditions, the influence of such conditions on block formation is important. We have found that an increase of the extracellular K+ concentration results in a complex, nonmonotonous change in critical anisotropies (Fig 7a). Before we analyze the curves shown in this figure, let us consider a more simple representation, shown in Fig 7b, which illustrates the dependency of the critical AR vs. potassium concentration ([K+]o) for several stimulation frequencies. (0.5 Hz, 1 Hz, 2 Hz and 2.5 Hz).

Bottom Line: We have examined the border between different areas of myocardial fiber alignment and have shown that blockage can occur for a wave traveling from a transverse fiber area to a longitudinal one.Such blockage occurs for reasonable values of the anisotropy ratio (AR): from 2.4 to 6.2 with respect to propagation velocities.Hyperkalemia affects the block formation in a complex, biphasic way.

View Article: PubMed Central - PubMed

Affiliation: Life Science Center, Moscow Institute of Physics and Technology, Dolgoprudny, Russia; Department of Physics and Astronomy, Ghent University, Ghent, Belgium.

ABSTRACT
Waveblock formation is the main cause of reentry. We have performed a comprehensive numerical modeling study of block formation due to anisotropy in Ten Tusscher and Panfilov (2006) ionic model for human ventricular tissue. We have examined the border between different areas of myocardial fiber alignment and have shown that blockage can occur for a wave traveling from a transverse fiber area to a longitudinal one. Such blockage occurs for reasonable values of the anisotropy ratio (AR): from 2.4 to 6.2 with respect to propagation velocities. This critical AR decreases by the suppression of INa and ICa, slightly decreases by the suppression of IKr and IKs, and substantially increases by the suppression of IK1. Hyperkalemia affects the block formation in a complex, biphasic way. We provide examples of reentry formation due to the studied effects and have concluded that the suppression of IK1 should be the most effective way to prevent waveblock at the areas of abrupt change in anisotropy.

No MeSH data available.


Related in: MedlinePlus