Relating the spectrum of cardiac signals to the spatiotemporal dynamics of cardiac sources

Abstract

An increasing number of studies use the spectrum of cardiac signals for analyzing the spatiotemporal dynamics of complex cardiac arrhythmias. However, the relationship between the spectrum of cardiac signals and the spatiotemporal dynamics of the underlying cardiac sources remains to date unclear. In this paper, we derive a mathematical expression relating the spectrum of cardiac signals to the spatiotemporal dynamics of cardiac sources and the measurement characteristics of the lead systems. Then, by using analytical methods and computer simulations we analyze the spectrum of cardiac signals measured by idealized lead systems during correlated and uncorrelated spatiotemporal dynamics. Our results show that lead systems can have distorting effects on the spectral envelope of cardiac signals, which depend on the spatial resolution of the lead systems and on the degree of spatiotemporal correlation of the underlying cardiac sources. In addition to this, our results indicate that the spectral features that do not depend on the spectral envelope, such as the dominant frequency, behave robustly against different choices of lead systems.

Dependence of cardiac spectrum on the spatial resolution of the electrode systems in a realistic model of the canine ventricles

“…In this study, the effects of volume conduction on the spectrum cardiac signals are investigated. Following previous theoretical results [10], we hypothesize that the spectral bandwidth is related to the degree of spatiotemporal correlation of cardiac dynamics and the spatial resolution of the electrode system. By simulating complex cardiac dynamics in a realistic model of the canine ventricles, we synthesize cardiac signals measured by electrode systems with different spatial resolutions and analyze their spectra.…”

“…In addition to this, spectral distortions produced by volume conduction could affect body-surface DF values. Theoretically, it is known that electrode systems characterized by large LEV produce spectra with low pass characteristics when the underlying spatiotemporal dyncamis are correlated [10]. This effect has also been observed in simple 2D simulation environments [8], [9].…”

“…We used the BW of cardiac signals to analyze the low-pass filtering effects of volume conduction. Since, according to [10], a relationship exists between the filtering effects of volume conduction and the spatial resolution of the electrode systems, we analyzed the relationship between the BW of cardiac signals and the LEV of the corresponding electrode system.…”

“…However, the exact correspondence between intracardiac and body-surface DF maps remains to date unclear. Theoretical and simulation studies indicate that volume conduction can affect the spectrum of body surface signals [8], [9], [10]. Specifically, it has been shown that the spectral bandwidth of signals measured during highly correlated cardiac dynamics is related to the spatial resolution of the electrode system.…”

Modelling the heart as a communication system

“…Cellular automata (CA) models have been used to study cardiac action potential propagation in several previous studies [32,33]. The model we used was developed by Alonso Atienza et al [34] who employed realistic restitution properties and the curvature phenomenon.…”