Abstract
Phase Singularities in a Cardiac Patch Model With a Non-conductive Fibrotic Area During Atrial FibrillationTiago P Almeida1, 2, 3*,Mark Nothstein4*, Xin Li1, 3, Michela Masè5, Flavia Ravelli6, Diogo C Soriano7, Arthur S Bezerra2, Fernando S Schlindwein1, 3, Takashi Yoneyama2, Olaf Dössel4, G André Ng1, 3,Axel Loewe41University of Leicester, UK; 2Instituto Tecnológico de Aeronáutica, Brazil; 3NIHR Leicester Cardiovascular Biomedical Research Centre, UK;4Karlsruhe Institute of Technology, KIT, Germany;5Eurac Research, Italy;6Università degli Studi di Trento, Italy;7Federal University of ABC, BrazilAbstractIn-silico cardiac patches with a non-conductive fibrotic areaswere used to investigate the occurrence and characteristics of rotors described by phase singularities (PSs). A rotor was generated in a virtual tissue patch represented by a Courtemanche model adapted to mimic AF conditions.Non-conductive fibrotic elements were incorporatedaround the center of the patch (densities of 20%, 30%,and 40%). Electrograms (EGMs) were calculated and their phase was determined using Hilbert transform. PSs were detected and PS density maps (PSDMs) were generated. Six attributes were used to investigate bipolar EGMs obtained from the original signals: sample entropy (SampEn), determinism (DET), peak-to-peak (PP), wave similarity (WS), organization index (OI),and cycle length (CL). 77.1% of the PSs occurred inside the fibrotic region –with a higher density in the border zone –for 20% density; 99.8% for 30%; 99.7% for 40%. SampEn was significantly higher in regions with PSDM≥5, while DET, PP,and WS were significantly lower (P<0.0001). PSs tended to meander outside the fibrotic area for lower fibrotic density. Bipolar EGM attributes offer a complementary way for rotor detection in the presence of non-conductive fibrosis.