The CLARRHMOS simulator takes a description of a given heart, built by the user, and computes the state of polarization/depolarization of every small region of the heart (named ``simulation cell'') and the overall effect of cells' polarization on the electrocardiogram, for a given period of time.
For the purposes of simulation, the myocardium and the conduction tissue
are decomposed in small regions, of equal volume and cubic shape,
named ``simulation cells''. Typically, they would have
a volume of 0.1-1 mm
. Every simulation cell is considered
to have homogenous electrophysiological properties, and to
depolarize and repolarize solidary.
The spatial placement of the cells, their properties and the way in which they interact with external factors make up the cord model. As just mentioned, in every cord model a set of external factors are defined (presumably such as digoxin blood level, vagal tonus and the like) and the way in which every cell is affected and responds to changes in these factors.
The actual values which the external factors take in time, other external effects, such as pacing or cardioversion, the spatial placement of the ECG electrodes, and a random seed, together with the cord model, constitute a complete set of data from which the behaviour of the model can be computed. These elements, which are not intrinsic to the myocardium, are called simulation environment.
Cord models and simulation environments can be described by the user as text files--in the writing of which various rules must be obeyed, which are described later in this document.