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Selected Publication:

Wiener, T.
Analyse von kardialen Nahfeldsignalen
[ Dissertation ] Technische Universität Graz ; 2012. pp.150.


Authors Med Uni Graz:
Wiener Thomas
Plank Gernot

The cardiac electric near field (CNF) is a time-varying electric field formed by potential differences at the surface of the heart muscle, which result from the sequence of electrical activation in the underlying tissue. Extracellular potentials measured close to the surface of the heart tissue with high spatial and temporal resolution, termed CNF signals, enable characterizing the pattern of activation. This may allow the identification of regions containing microstructural heterogeneities which are seen as potential substrates for the genesis of arrhythmias. The aim of this work is the characterization of local propagation of activation by analysis of CNF signals recorded during electrophysiological in-vitro experiments with heart preparations. Special emphasis is placed on the analysis of fractionated CNF signals which are attributed to heterogeneous structure in the underlying heart tissue. Algorithms for the processing of CNF signals are developed using waveforms obtained from computer simulations of virtual heart tissue. To test their robustness, noise of the same characteristics as observed under experimental conditions was added. The main findings are the reliable computation of local conduction velocity, the introduction of a quantitative measure of CNF signal fractionation, and the decomposition of fractionated signals into nonfractionated components. Moreover, a novel approach to the classification of cardiac fibrosis through the analysis of CNF signals is presented.

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