# A Mathematical Model of Action Potential Heterogeneity in Adult Rat Left Ventricular Myocytes

#### Model Status

This CellML version of the model represents the epicardial cell. A number of inconsistencies in units and errors in equations from version 07 were fixed in this version. In addition to the formulation given by the paper and the author's later Corrections document, the IStim current has been adjusted to produce 1 Hz stimulations for 10 seconds.

#### Model Structure

Over the past decade electrophysiological studies have revealed transmural heterogeneity, or differences in the action potential waveforms recorded in cells isolated from the epicardial and the endocardial tissues in the left ventricles of mammalian hearts.

The adult rat has been widely used as an experimental model to investigate the electrical heterogeneity in the left ventricle under normal conditions and pathophysiological states. From this biophysical, experimental data, derived from patch clamp experiments, Sandeep V. Pandit, Robert B. Clark, Wayne R. Giles and Semahat S. Demir have developed a mathematical model of action potential heterogeneity in adult rat left ventricular myocytes (see the figure below). The mathematical models for the epicardial and endocardial cells of the rat left ventricle are based on the classical formulation of Hodgkin and Huxley (please see the CellML version of The Hodgkin-Huxley Squid Axon Model, 1952 for more details), and are therefore similar to previous computational work carried out by this research group (see Demir *et al.* Sinoatrial Node Model 1994 and Demir *et al.* Sinoatrial Node Model 1999). The endocardial cell model is based on the epicardial formulation with only slight modifications in certain parameters and equations.

The complete original paper reference is cited below:

A Mathematical Model of Action Potential Heterogeneity in Adult Rat Left Ventricular Myocytes, , Sandeep V. Pandit, Robert B. Clark, Wayne R. Giles and Semahat S. Demir, 2001,
*Biophysical Journal*
, 81, 3029-3051. (Full text and PDF versions of the article are available for Journal Members on the Biophysical Journal website.) PubMed ID: 11720973

A fluid compartment model of the rat epicardial/endocardial ventricular cell. |