Directed networks as a novel way to describe and analyze cardiac excitation: Directed Graph mapping

Abstract

Networks provide a powerful methodology with applications in a variety of biological, technological and social systems such as analysis of brain data, social networks, internet search engine algorithms, etc. To date, directed networks have not yet been applied to characterize the excitation of the human heart. In clinical practice, cardiac excitation is recorded by multiple discrete electrodes. During (normal) sinus rhythm or during cardiac arrhythmias, successive excitation connects neighboring electrodes, resulting in their own unique directed network. This in theory makes it a perfect fit for directed network analysis. In this study, we applied directed networks to the heart in order to describe and characterize cardiac arrhythmias. Proofof-principle was established using in-silico and clinical data. We demonstrated that tools used in network theory analysis allow to determine the mechanism and location of certain cardiac arrhythmias. We show that the robustness of this approach can potentially exceed the existing state-of-the art methodology used in clinics. Furthermore, implementation of these techniques in daily practice can improve accuracy and speed of cardiac arrhythmia analysis. It may also provide novel insights in arrhythmias that are still incompletely understood. network theory| cardiac arrhythmia Correspondence: nele.vandersickel@ugent.be

Atrial conduction velocity mapping: clinical tools, algorithms and approaches for understanding the arrhythmogenic substrate

“…These propagation vectors can either be constructed using CV vectors calculated through LAT assignment, or through tracking constant values of another variable -for example, isopotential or isophase methods. Directed graph mapping assigns propagation vectors and uses a network theory approach to determine re-entrant wavefront activation directions [94] and determine atrial tachycardia and flutter mechanisms [95,96]. Pathways of activation during atrial fibrillation can be assessed through optical flow mapping or Electrographic Flow mapping [97,98], and this analysis is available in the clinic through Ablacon Ablamap Software [98].…”

The Why, How, and When of Representations for Complex Systems

“…If we apply this idea to the graph framework, a directed graph is one where each edge is now an ordered set of two nodes. Directed graphs have proven extremely useful in many contexts from scheduling and monitoring workflows [113,6] to cardiac excitation modeling [215] to understanding percolation processes relevant to wildfires and other explosive phenomena [199,66]. Moving to simplicial complexes, directionality is still quite natural.…”

The why, how, and when of representations for complex systems

“…If we apply this idea to the graph formalism, a directed graph is one where each edge is now an ordered set of two nodes. Directed graphs have proven extremely useful in many contexts from scheduling and monitoring workflows [107,1] to cardiac excitation modeling [202] to understanding percolation processes relevant to wild fires and other explosive phenomena [189,61]. Moving to simplicial complexes, directionality is still quite natural.…”