Numerical simulations of cardiac arrhythmia and defibrillation

The goal of the present project is to perform realistic computer simulations of reentrant arrhythmia and defibrillation of the heart. The motivation for this project is based on the fact that the underlying mechanisms of both reentrant arrhythmia and defi brillation are poorly understood. It is hard to observe such activity in the heart wall using traditional techniques, such as in lab experiments. Computer simulations based on advanced mathematical models offer a detailed picture of the electrical activit y throughout the volume of the heart, and may therefore give a more detailed picture of the arrhythmic activity. This project has two primary goals; one is to extend existing simulation software with improved numerical methods and more advanced mathemati cal models for cell dynamics in the heart. The second aim is to look into two particular applications of the solver, with the intention of obtaining clinically relevant results. The first application involves a study of the role that the calcium concentr ation has on the outcome of the shock. A strong electric shock exposed to the heart is believed to cause calcium overload, which in turn may lead to reentrant arrhythmias. The second application focuses on a study of the connection between T-wave alternan s, seen on the ECG signal, and ventricular fibrillation. It is known that these T-wave alternans may be a predictor of such disturbances in the heart rythm, but the underlying mechanisms are not yet uncovered.