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Infarct and fibrosis in cardiac tissue: models of arrhythmia and perfusion in the heart

Kolloquium der Abteilung 8

The microscopic structure of cardiac tissue can be considerably altered under diseased conditions, such as infarct, heart failure and different types of myocarditis. Typically, the changes involve an increase of tissue heterogeneity, whereas fibrosis usually plays an important role. Nowadays, there exist at least two different clinical procedures that aim on the quantification of cardiac regions with fibrosis: i) by invasively measuring the electric signals on cardiac tissues using catheters; and ii) by the non-invasive technique of contrast-enhanced MRI that measures perfusion. In this talk, we show how these two measurements can be reproduced by mathematical and computational models. We show that the propagation of electric waves in tissue with regions of fibrotic infiltration and the associated fractionated electrograms are well captured by the cardiac bidomain model (that considers intracellular and extracellular domains). In addition, we present a new bidomain model (that considers intravascular and extravascular/interstitial domains) that is based on classical formulations of porous media that can also reproduce the measurements of cardiac perfusion obtained by contrast-enhanced MRI.