"The roles of sustained components of INa and IKv43 in shaping the action potentials (AP) of myocytes isolated from the canine left ventricle (LV) have not been studied in detail. Here we investigate the hypothesis that these two currents can contribute substantially to heterogeneity of early repolarization and arrhythmic risk.... The resulting simulations illustrate ways in which KChIP2- and Ca2+- dependent control of IKv43 can result in a sustained outward current that can neutralize INaL in a rate- and myocyte subtype-dependent manner. Both these currents appear to play significant roles in modulating AP duration and rate dependence in midmyocardial myocytes. ... By design, these models allow upward integration into organ models or may be used as a basis for further investigations into cellular heterogeneities." See paper for more and details.
Model Type: Neuron or other electrically excitable cell; Electrogenic pump
Cell Type(s): Heart cell; Cardiac ventricular cell
Currents: I Na,t; I A; I K; Late Na; Na/Ca exchanger; I_Na,Ca; I_SERCA; Na/K pump
Genes: Kv4.3 KCND3
Model Concept(s): Ion Channel Kinetics; Action Potentials; Heart disease; Sodium pump; Markov-type model
Simulation Environment: MATLAB
Implementer(s): Flaim, Sarah [flaim at comlab.ox.ac.uk]
References:
Flaim SN, Giles WR, McCulloch AD. (2006). Contributions of sustained INa and IKv43 to transmural heterogeneity of early repolarization and arrhythmogenesis in canine left ventricular myocytes. American journal of physiology. Heart and circulatory physiology. 291 [PubMed]