Early afterdepolarisations and ventricular arrhythmias in cardiac tissue: a computational study
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Afterdepolarisations are associated with arrhythmias in the heart, but are difficult to study experimentally. In this study we used a simplified computational model of 1D and 2D cardiac ventricular tissue, where we could control the size of the region generating afterdepolarisations, as well as the properties of the afterdepolarisation waveform. Provided the size of the afterdepolarisation region was greater than around 1 mm, propagating extrasystoles were produced in both 1D and 2D. The number of extrasystoles produced depended on the amplitude, period, and duration of the oscillatory EAD waveform. In 2D, re-entry was also initiated for specific combinations of EAD amplitude, period, and duration, with the afterdepolarisation region acting as a common pathway. The main finding from this modelling study is therefore that afterdepolarisations can act as potent sources of propagating extrasystoles, as well as a source of re-entrant activation.
KeywordsHeart Re-entry Fibrillation Excitable media Early afterdepolarisations
We would like to thank the British Heart Foundation for funding this work through the award of Project Grant PG/03/102/1582. We would also like to thank both the Integrative Biology eScience project (EPSRC GR/S72023/01) and the White Rose Grid (http://www.wrgrid.org.uk) for making computer resources available for this work. We are especially grateful to Flavio Fenton and Elizabeth Cherry from Cornell University for providing parameter sets and source code for the 4VSIM model.
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