Comlekoglu, Tien

Weinberg, Seth H

English

VCU Scholars Compass

Virginia Commonwealth University
VCU Scholars Compass
Biology and Medicine Through Mathematics
Conference 2018
May 30th, 5:00 PM - 5:30 PM
Memory affects alternans under voltage- and
calcium- mediated conditions in a fractional-order
cardiomyocyte model
Tien Comlekoglu
comlekoglutn@vcu.edu
Seth H. Weinberg
Virginia Commonwealth University
Follow this and additional works at: https://scholarscompass.vcu.edu/bamm
Part of the Life Sciences Commons, Medicine and Health Sciences Commons, and the Physical
Sciences and Mathematics Commons
This Event is brought to you for free and open access by the Dept. of Mathematics and Applied Mathematics at VCU Scholars Compass. It has been
accepted for inclusion in Biology and Medicine Through Mathematics Conference by an authorized administrator of VCU Scholars Compass. For
more information, please contact libcompass@vcu.edu.
https://scholarscompass.vcu.edu/bamm/2018/wednesday/13
Memory affects alternans under voltage- and calcium- mediated conditions in a 
fractional-order cardiomyocyte model 
 
Tien Comlekoglu, Seth H. Weinberg 
 
The electrical behavior of cardiomyocytes is typically approximated with ideal resistor-
capacitor circuit networks. However, non-ideal circuit components may more accurately model 
excitable cell properties. These non-ideal circuit components are governed by fractional-order 
dynamics and impart capacitive memory effects that contribute a history dependence to the 
transmembrane potential. Our prior work revealed that in a minimal model driven solely by 
voltage instabilities, membrane capacitive memory acts to shorten the action potential duration 
(APD) and suppresses alternans, a beat to beat alternation in the APD. We investigate here the 
effect of memory in a model driven by both intracellular calcium cycling as well as 
transmembrane voltage dynamics. Two parameterizations were studied corresponding to 
concordant calcium driven and voltage driven alternans mechanisms. Simulations for fractional 
orders ranging from 1 to 0.85 were performed with cycle lengths (CL) between 200 and 600 
milliseconds. Consistent with our recent work, APD was shortened at smaller fractional orders. 
Capacitive memory also decreased peak intracellular calcium concentrations per beat. 
Membrane capacitive memory suppressed alternans in the calcium driven at decreasing 
fractional orders. However, intermediate fractional orders between 0.9 and 0.95 promoted 
alternans in the voltage driven parameterization. Our results suggest that membrane capacitive 
memory plays a role in both suppression and formation of alternans under both voltage and 
calcium driven mechanisms. 


Memory affects alternans under voltage- and calcium- mediated conditions in a fractional-order cardiomyocyte model

Virginia Commonwealth UniversityVCU Scholars CompassBiology and Medicine Through MathematicsConference 2018May 30th, 5:00 PM - 5:30 PMMemory affects alternans under voltage- andcalcium- mediated conditions in a fractional-ordercardiomyocyte modelTien Comlekoglucomlekoglutn@vcu.eduSeth H. WeinbergVirginia Commonwealth UniversityFollow this and additional works at: https://scholarscompass.vcu.edu/bammPart of the Life Sciences Commons, Medicine and Health Sciences Commons, and the PhysicalSciences and Mathematics CommonsThis Event is brought to you for free and open access by the Dept. of Mathematics and Applied Mathematics at VCU Scholars Compass. It has beenaccepted for inclusion in Biology and Medicine Through Mathematics Conference by an authorized administrator of VCU Scholars Compass. Formore information, please contact libcompass@vcu.edu.https://scholarscompass.vcu.edu/bamm/2018/wednesday/13Memory affects alternans under voltage- and calcium- mediated conditions in a fractional-order cardiomyocyte model  Tien Comlekoglu, Seth H. Weinberg  The electrical behavior of cardiomyocytes is typically approximated with ideal resistor-capacitor circuit networks. However, non-ideal circuit components may more accurately model excitable cell properties. These non-ideal circuit components are governed by fractional-order dynamics and impart capacitive memory effects that contribute a history dependence to the transmembrane potential. Our prior work revealed that in a minimal model driven solely by voltage instabilities, membrane capacitive memory acts to shorten the action potential duration (APD) and suppresses alternans, a beat to beat alternation in the APD. We investigate here the effect of memory in a model driven by both intracellular calcium cycling as well as transmembrane voltage dynamics. Two parameterizations were studied corresponding to concordant calcium driven and voltage driven alternans mechanisms. Simulations for fractional orders ranging from 1 to 0.85 were performed with cycle lengths (CL) between 200 and 600 milliseconds. Consistent with our recent work, APD was shortened at smaller fractional orders. Capacitive memory also decreased peak intracellular calcium concentrations per beat. Membrane capacitive memory suppressed alternans in the calcium driven at decreasing fractional orders. However, intermediate fractional orders between 0.9 and 0.95 promoted alternans in the voltage driven parameterization. Our results suggest that membrane capacitive memory plays a role in both suppression and formation of alternans under both voltage and calcium driven mechanisms. 

https://scholarscompass.vcu.edu/cgi/viewcontent.cgi?article=1213&amp;context=bamm

Memory affects alternans under voltage- and calcium- mediated conditions in a fractional-order cardiomyocyte model

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