Current Graduate Research Projects

1. Development of a realistic human atria computer model. Funded by Heart and Stroke Foundation of Canada
   This project involves performing numerical simulations to better understand the underlying causes of atrial fibrillation. A geometrically realistic model with the major features has been developed based on CT data (supplied by C Peskin/D McQueen). The figure shows a reentrant pattern of electrical excitation in the model.
   
   Check out this movie of normal sinoatrial node activation.

2. Nonlinear signal processing of ICD electrogram data. Joint with Dr. Leon and Dr. Shane Kimber (University of Alberta).
   Analyze electrogram recordings from implantable cardiac defibrillators (below) to develop a more intelligent shocking algorithm.
   
3. Development of modelling techniques to improve performance of bidomain simulations. Joint with Dr. Gernot Plank Dr. Rodrigo Weber Dos Santos Funded by NSERC.
   The bidomain description of electrical activity in cardiac tissue is the most complete but is computationally demanding. Techniques to decrease the compuatational burden, thereby allowing larger systems on the order of millions of nodes, to be modelled, are sought. One avenue to explore is the development of parallel algorithms under a variety of parallel environments like OpenMP, MPI and pthreads. Also to be considered are computational techniques like multigrid methods, the finite element method, and the interconnected cable method. Finally, mathematical analysis of the equations may allow insignificant terms to be neglected. Below is an illustration of how the solution of the extracellular potential during propagation is affected by iterative solver tolerance.
   
   AVI movies of the induction of reentry in rabbit ventricles are available as surface maps and semi-transparent renderings.
   We are also interested in computing the magnetic field produced by cardiac electrical activity. This field is the basis of the magnetocardiogram which may provide more information than the electrocardiogram. Here are movies of the current density and magnetic field produced by a planar wave as it propagates down a slab.

4. Modelling the Purkinje System. . The Purkinje System is the special wiring of the heart, responsible for its rapid activation. However, the role it plays during arrhythmia formation and defibrillation remains unknown. Due to the difficulty in imaging it and the entire organ at the same time, modelling offers the best way to judge how it affects arrhythmia induction, and how it reacts to strong electrical shocks.
   
   
5. Spread of electrical current in arterioles Joint with Dr. Donald Welsh, Faculty of Medicine, University of Calgary. Funded by HSFC
   Arterioles are composed of a layer of longitudinally oriented endothelial cells ( stained in panel A below) covered by layers of circumferentially running smooth muscle cells (2 cells stained in panel B). Blood flow is controlled by the smooth muscle tone which depends on its transmembrane voltage. Each cell type is well coupled to itself via gap junctions but coupling between the 2 cell types is much poorer. The goal of this research is to better understand how electrical changes in one part of a blooood vessel propagate to affect tone in another part and ultimately control blood flow. This has implications in many vascular diseases.
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