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Regional differences in APD restitution can initiate wavebreak and re-entry in cardiac tissue: A computational study

Clayton, R.H. and Taggart, P. (2005) Regional differences in APD restitution can initiate wavebreak and re-entry in cardiac tissue: A computational study. BioMedical Engineering OnLine, 4 (54). ISSN 1475-925X

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Abstract

Background

Regional differences in action potential duration (APD) restitution in the heart favour arrhythmias, but the mechanism is not well understood.

Methods

We simulated a 150 × 150 mm 2D sheet of cardiac ventricular tissue using a simplified computational model. We investigated wavebreak and re-entry initiated by an S1S2S3 stimulus protocol in tissue sheets with two regions, each with different APD restitution. The two regions had a different APD at short diastolic interval (DI), but similar APD at long DI. Simulations were performed twice; once with both regions having steep (slope > 1), and once with both regions having flat (slope < 1) APD restitution.

Results

Wavebreak and re-entry were readily initiated using the S1S2S3 protocol in tissue sheets with two regions having different APD restitution properties. Initiation occurred irrespective of whether the APD restitution slopes were steep or flat. With steep APD restitution, the range of S2S3 intervals resulting in wavebreak increased from 1 ms with S1S2 of 250 ms, to 75 ms (S1S2 180 ms). With flat APD restitution, the range of S2S3 intervals resulting in wavebreak increased from 1 ms (S1S2 250 ms), to 21 ms (S1S2 340 ms) and then 11 ms (S1S2 400 ms).

Conclusion

Regional differences in APD restitution are an arrhythmogenic substrate that can be concealed at normal heart rates. A premature stimulus produces regional differences in repolarisation, and a further premature stimulus can then result in wavebreak and initiate re-entry. This mechanism for initiating re-entry is independent of the steepness of the APD restitution curve.

Item Type: Article
Copyright, Publisher and Additional Information: © 2005 Clayton and Taggart; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Academic Units: The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Computer Science (Sheffield)
Depositing User: Repository Officer
Date Deposited: 15 Mar 2006
Last Modified: 08 Feb 2013 16:49
Published Version: http://www.biomedical-engineering-online.com/conte...
Status: Published
Refereed: Yes
Identification Number: 10.1186/1475-925X-4-54
URI: http://eprints.whiterose.ac.uk/id/eprint/1084

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