A logical state model of circus movement atrial flutter role of anatomic obstacles, anisotropic conduction and slow conduction zones on induction, sustenance, and overdrive paced modulation of reentrant circuits

Experimental models of atrial fibrillation/flutter

Animal models that mimic disease states or abnormal physiological events are tools that assist the investigator to understand the mechanism responsible for pathophysiological conditions. Atrial arrhythmias have intrigued physicians and cardiologists for decades. Thus the development of animal models for the study of atrial arrhythmias facilitate the investigation of these abnormal rhythms. Moreover, as our understanding of arrhythmias advances, so does the therapy designed to correct the condition, which ultimately improves the patient's clinical outcome. This manuscript describes a variety of animal models that have been utilized for the exploration of atrial arrhythmia generation and maintenance, as well as models used to evaluate the efficacy of putative antiarrhythmics agents.

An interactive 3D anisotropic cellular automata model of the heart

A 3D cellular anisotropic automata model with modifiable geometry is described. The modeling parameters include grain size, fiber orientation, and free-wall and septal thickness. From this modifiable model, three specific models corresponding to normal heart, left ventricular hypertrophy, and ventricular dilatation were generated. Each model is a conduction and propagation model in which the atria, the major atrial vessel bases, the ventricles, and the specialized conduction system are represented. Muscle tissues are modeled as bundles of fibers with anisotropic conduction speed of the activation wavefronts. Regional variations of conduction, refractory gradients, and regional potential gradients can also be specified before each simulation. Each element has adaptive properties with respect to cycle length and to the prematurity of incoming impulses. Action potentials can be specified for each cell and an equivalent source formulation is carried out to simulate the vectorcardiogram and the corresponding 12-standard-lead electrocardiogram.

Spatio-temporal reasoning for multi-scale modeling in cardiology

In this paper, we present an overview of the CARDIOLAB environment where the heart's electrical activity is modeled at distinct space and time scales. CARDIOLAB uses three models, two of which are based on cellular automata, and the third on qualitative simulation. They are combined around a blackboard for multi-scale quantitative and qualitative modeling of cardiac electrical activity. A general account on how spatio-temporal representation and reasoning methods are applied to produce heuristic associations is also presented.