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Simulation of Ectopic Pacemakers in the Heart: Multiple Ectopic Beats Generated by Reentry inside Fibrotic Regions.

Gouvêa de Barros B, Weber Dos Santos R, Lobosco M, Alonso S - Biomed Res Int (2015)

Bottom Line: Both models produce similar results when describing action potential propagation in homogeneous tissue; however, they slightly differ in the generation of ectopic beats in heterogeneous tissue.Nevertheless, both models present the generation of reentry inside fibrotic tissues.In turn, such activity has been related to trigger fibrillation in the atria and in the ventricles in clinical and animal studies.

View Article: PubMed Central - PubMed

Affiliation: Graduate Program in Computational Modeling, Federal University of Juiz de Fora, 36036-330 Juiz de Fora, MG, Brazil.

ABSTRACT
The inclusion of nonconducting media, mimicking cardiac fibrosis, in two models of cardiac tissue produces the formation of ectopic beats. The fraction of nonconducting media in comparison with the fraction of healthy myocytes and the topological distribution of cells determines the probability of ectopic beat generation. First, a detailed subcellular microscopic model that accounts for the microstructure of the cardiac tissue is constructed and employed for the numerical simulation of action potential propagation. Next, an equivalent discrete model is implemented, which permits a faster integration of the equations. This discrete model is a simplified version of the microscopic model that maintains the distribution of connections between cells. Both models produce similar results when describing action potential propagation in homogeneous tissue; however, they slightly differ in the generation of ectopic beats in heterogeneous tissue. Nevertheless, both models present the generation of reentry inside fibrotic tissues. This kind of reentry restricted to microfibrosis regions can result in the formation of ectopic pacemakers, that is, regions that will generate a series of ectopic stimulus at a fast pacing rate. In turn, such activity has been related to trigger fibrillation in the atria and in the ventricles in clinical and animal studies.

No MeSH data available.


Related in: MedlinePlus

Reentry ((b)-(d)) and nonreentry ((a)-(c)) of action potential generated by the heterogeneous structure of the tissue in the microscopic ((a)-(c)) and the discrete ((b)-(d)) model. ((a)-(b)) Wave rapidly propagates to the right following the direction of the fibers in the microscopic (a) and in the discrete model (b), for t = 40 ms. The wave does not reenter into the tissue in the microscopic model (c), for t = 100 ms. A piece of the wave reenters into the tissue in the discrete model (d), for t = 100 ms.
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fig12: Reentry ((b)-(d)) and nonreentry ((a)-(c)) of action potential generated by the heterogeneous structure of the tissue in the microscopic ((a)-(c)) and the discrete ((b)-(d)) model. ((a)-(b)) Wave rapidly propagates to the right following the direction of the fibers in the microscopic (a) and in the discrete model (b), for t = 40 ms. The wave does not reenter into the tissue in the microscopic model (c), for t = 100 ms. A piece of the wave reenters into the tissue in the discrete model (d), for t = 100 ms.

Mentions: On the other hand, some realizations using the same topologies for both models gave rise to different final dynamics. Figure 12 shows the comparison between two simulations with the two models. While we observe a reentry in the discrete model no reentry is observed in the simulation with the microscopic model. The wave initially propagates in the two models following a very similar dynamics; however, later on the simulation, propagation stops in the microscopic model, whereas in the discrete model it persists as a reentry wave.


Simulation of Ectopic Pacemakers in the Heart: Multiple Ectopic Beats Generated by Reentry inside Fibrotic Regions.

Gouvêa de Barros B, Weber Dos Santos R, Lobosco M, Alonso S - Biomed Res Int (2015)

Reentry ((b)-(d)) and nonreentry ((a)-(c)) of action potential generated by the heterogeneous structure of the tissue in the microscopic ((a)-(c)) and the discrete ((b)-(d)) model. ((a)-(b)) Wave rapidly propagates to the right following the direction of the fibers in the microscopic (a) and in the discrete model (b), for t = 40 ms. The wave does not reenter into the tissue in the microscopic model (c), for t = 100 ms. A piece of the wave reenters into the tissue in the discrete model (d), for t = 100 ms.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4637158&req=5

fig12: Reentry ((b)-(d)) and nonreentry ((a)-(c)) of action potential generated by the heterogeneous structure of the tissue in the microscopic ((a)-(c)) and the discrete ((b)-(d)) model. ((a)-(b)) Wave rapidly propagates to the right following the direction of the fibers in the microscopic (a) and in the discrete model (b), for t = 40 ms. The wave does not reenter into the tissue in the microscopic model (c), for t = 100 ms. A piece of the wave reenters into the tissue in the discrete model (d), for t = 100 ms.
Mentions: On the other hand, some realizations using the same topologies for both models gave rise to different final dynamics. Figure 12 shows the comparison between two simulations with the two models. While we observe a reentry in the discrete model no reentry is observed in the simulation with the microscopic model. The wave initially propagates in the two models following a very similar dynamics; however, later on the simulation, propagation stops in the microscopic model, whereas in the discrete model it persists as a reentry wave.

Bottom Line: Both models produce similar results when describing action potential propagation in homogeneous tissue; however, they slightly differ in the generation of ectopic beats in heterogeneous tissue.Nevertheless, both models present the generation of reentry inside fibrotic tissues.In turn, such activity has been related to trigger fibrillation in the atria and in the ventricles in clinical and animal studies.

View Article: PubMed Central - PubMed

Affiliation: Graduate Program in Computational Modeling, Federal University of Juiz de Fora, 36036-330 Juiz de Fora, MG, Brazil.

ABSTRACT
The inclusion of nonconducting media, mimicking cardiac fibrosis, in two models of cardiac tissue produces the formation of ectopic beats. The fraction of nonconducting media in comparison with the fraction of healthy myocytes and the topological distribution of cells determines the probability of ectopic beat generation. First, a detailed subcellular microscopic model that accounts for the microstructure of the cardiac tissue is constructed and employed for the numerical simulation of action potential propagation. Next, an equivalent discrete model is implemented, which permits a faster integration of the equations. This discrete model is a simplified version of the microscopic model that maintains the distribution of connections between cells. Both models produce similar results when describing action potential propagation in homogeneous tissue; however, they slightly differ in the generation of ectopic beats in heterogeneous tissue. Nevertheless, both models present the generation of reentry inside fibrotic tissues. This kind of reentry restricted to microfibrosis regions can result in the formation of ectopic pacemakers, that is, regions that will generate a series of ectopic stimulus at a fast pacing rate. In turn, such activity has been related to trigger fibrillation in the atria and in the ventricles in clinical and animal studies.

No MeSH data available.


Related in: MedlinePlus