Spiral Wave Initiation in Reaction-Diffusion-Mechanics Systems: A Model for the Onset of Reentrant Cardiac Arrhythmia

Abstract

Heart failure due to cardiac arrhythmias is a major cause of death in the industrialized world. Cardiac arrhythmia is often caused by spi- ral waves of electrical activity in the cardiac muscle. Therefore, it is a major task in cardiology to understand the mechanisms of spiral wave initiation in the heart. Valuable insights into mechanisms of the onset of arrhythmia have been achieved by studying spiral wave initiation in reaction-di usion systems as models for cardiac tissue. However, most of these studies did not take the deformation of the heart into account. Yet mechanical changes have been shown to signi cantly a ect heart function- ing. In fact, deformation of the heart has been demonstrated to be able to cause, but also to abolish dangerous cardiac arrhythmias. This thesis fo- cuses on the question: \What is the e ect of deformation on mechanisms of the onset of reentrant cardiac arrhythmia?". To study this problem, mechanically discrete reaction-di usion-mechanics models of cardiac elec- tromechanical activity are developed, and spiral wave initiation is studied in these systems as a model for the onset of reentrant cardiac arrhythmia. As a result, mechanisms of mechanically caused spiral wave activity are found in homogeneous and inhomogeneous reaction-di usion-mechanics systems. This thesis highlights the importance of mechanical determi- nants for the onset of cardiac arrhythmias.