Identification of Dominant Excitation Patterns and Sources of Atrial Fibrillation by Causality Analysis

Short title: Causal Identification of Atrial Fibrillation Sources

Miguel Rodrigo, MSa, Andreu M. Climent, PhDb, Alejandro Liberos, MSa, David Calvo, MD, PhDb, Francisco Fernández-Avilés, MD, PhDb, OmerBerenfeld, PhDc, Felipe Atienza, MD, PhDb*, Maria S. Guillem, PhDa*

a ITACA, Universitat Politécnica de Valencia, Valencia, Spain. Camí de Vera s/n 46022.

bCardiologyDepartment, Hospital General Universitario Gregorio Marañón, Instituto de

Investigación Sanitaria Gregorio Marañón, Madrid, Spain. CalleDrEsquerdo 46 28007.

c Center for Arrhythmia Research, University of Michigan, Ann Arbor, USA. 2800 Plymouth Road 48109 MI.

* These two authors contributed equally to this work as senior authors.

Addressforcorrespondence:

Maria S. Guillem: BioITACA, 1ªplanta, Edificio 8G, Ciudad Politécnica de la Innovación, Universidad Politécnica de Valencia, Camino de Vera sn 46022 Valencia (Spain), Tel. +34 96 387 79 68, Fax +34 96 387 72 79, email:

orFelipe Atienza: CardiologyDepartment, Hospital General Universitario Gregorio Marañón, C/ DrEsquerdo 46, 28007, Madrid (Spain), Tel. +34 91 586 86 87, email:.

Mathematical models of the atrial electrical activity

A realistic 3D model with the most recent atrial cell formulation [1-4] was used to simulate the atrial electrical activity during fibrillation (285,780 nodes and 566,549 triangular patches, 673.38±130.31 µm between nodes). A gradient on the electrophysiological properties of the atrial myocardium, specifically on Ik,ACH, IK1, INa and ICaL [3, 5], was introduced into the mathematical model to obtain propagation patterns with heterogeneous activation rates. The system of differential equations in the atrial cell model was solved by using Runge-Kutta integration based on a graphic processors unit (NVIDIA Tesla C2075 6G) [6]. For each simulation, a uniform mesh of unipolar EGMs was calculated surrounding the epicardial surface (1 mm distance) under the assumption of a homogenous, unbounded and quasi-static conducting medium by summing up all effective dipole contributions over the entire model as:

(1)

where is the distance vector between the measuring point and a point in the tissue domain ( is the distance scalar), anddenotes the gradient operator. Computed electrograms were stored for processing at a sampling frequency of 1 kHz.

An ensemble of 32 different mathematical models was simulated, composed of 14 AF patterns driven by a single rotor at varying locations of the LA (PVs, PLAW and LA appendage), 17 AF patterns driven by a single rotor at varying locations of the RA (free RA wall and RA appendage) and 1 AF pattern driven by multiple drivers.The AF pattern driven by multiple drivers was analyzed both for the raw EGMs and with additional 20% noise in the EGMs.

References

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