Computer Model of Structure and Function of Atrial Tissue

Erwin Schrödinger Fellowship J 1966 Computer Modell of Structur and Function of Atrial Tissue Gernot PLANK 09.10.2000 Facing an increasingly ageing population structural diseases of the heart leading to disturbances of the cardiac excitation spread (arrhythmias) will be encountered more frequently. Besides the treatment of such diseases with drug therapy in recent years a treatment based on the localisation and ablation of arrhythmogenic tissue with radiofrequency impulses (RF-catheter ablation) was established with success. For this treatment as much information as possible on structure and function of the underlying cardiac tissue is needed to keep the target area of ablation as small as possible in order to prevent damage of surrounding tissue which is possibly indispensable for the spread of the cardiac impulse. Essential improvements of these techniques can be expected from computer simulations of intracavitary potentials, from refinement of measurements close to the cardiac current sources and from the analysis of signals based on these simulation results. Improved computer assistance in signal analysis could prevent misinterpretations and might contribute valuable additional information on the underlying substrate. To provide a solid theoretical fundament for such an assistance extensive pre- liminary computer simulations of catheter interventions are required to under- stand in detail the mechanisms of the formation of intracavitary signals and to facilitate a reliable computer assisted interpretation. This project will be centred around the simulation of excitation spread in specific pieces of cardiac tissue which are assumed to play an important role in the genesis of atrial arrhythmias. The model should take into account the anatomical structure of the tissue and should use an adequate description of the dynamic behaviour of the membrane. The work will be focused on some regions of interest in the atrium like the terminal crest in conjunction with the posterior pectinate muscles. From a detailed simulation of the electric sources within the atrial tissue it will be possible to deduce extracellular signals which are equivalent to measurements of potentials and fields with a catheter probe. Recent findings concerning the properties of the electric near field (micro-vector-loops) deduced from simulations with an anisotropic continuous tissue model will be scrutinised with this model. It will be investigated if some of the appealing features of the electric near field are preserved in an anatomically and functionally more realistic tissue model and if these simulation results might be might be used for the computer assisted guidance of catheter interventions and analysis of intracavitary signals.