Imperial College London

Dr Fu Siong Ng

Faculty of MedicineNational Heart & Lung Institute

Clinical Senior Lecturer in Cardiac Electrophysiology



+44 (0)20 7594 Website




ICTEM buildingHammersmith Campus






BibTex format

author = {Roney, C and Ng, FS and Debney, M and Eichhorn, C and Nachiappan, A and Chowdhury, R and Qureshi, N and Cantwell, C and Tweedy, J and Niederer, S and Peters, N and Vigmond, E},
doi = {europace/euy235},
journal = {EP-Europace},
pages = {iii3--iii15},
title = {Determinants of new wavefront locations in cholinergic atrial fibrillation},
url = {},
volume = {20},
year = {2018}

RIS format (EndNote, RefMan)

AB - AimsAtrial fibrillation (AF) wavefront dynamics are complex and difficult to interpret, contributing to uncertainty about the mechanisms that maintain AF. We aimed to investigate the interplay between rotors, wavelets, and focal sources during fibrillation.Methods and resultsArrhythmia wavefront dynamics were analysed for four optically mapped canine cholinergic AF preparations. A bilayer computer model was tuned to experimental preparations, and varied to have (i) fibrosis in both layers or the epicardium only, (ii) different spatial acetylcholine distributions, (iii) different intrinsic action potential duration between layers, and (iv) varied interlayer connectivity. Phase singularities (PSs) were identified and tracked over time to identify rotational drivers. New focal wavefronts were identified using phase contours. Phase singularity density and new wavefront locations were calculated during AF. There was a single dominant mechanism for sustaining AF in each of the preparations, either a rotational driver or repetitive new focal wavefronts. High-density PS sites existed preferentially around the pulmonary vein junctions. Three of the four preparations exhibited stable preferential sites of new wavefronts. Computational simulations predict that only a small number of connections are functionally important in sustaining AF, with new wavefront locations determined by the interplay between fibrosis distribution, acetylcholine concentration, and heterogeneity in repolarization within layers.ConclusionWe were able to identify preferential sites of new wavefront initiation and rotational activity, in order to determine the mechanisms sustaining AF. Electrical measurements should be interpreted differently according to whether they are endocardial or epicardial recordings.
AU - Roney,C
AU - Ng,FS
AU - Debney,M
AU - Eichhorn,C
AU - Nachiappan,A
AU - Chowdhury,R
AU - Qureshi,N
AU - Cantwell,C
AU - Tweedy,J
AU - Niederer,S
AU - Peters,N
AU - Vigmond,E
DO - europace/euy235
EP - 15
PY - 2018///
SN - 1099-5129
SP - 3
TI - Determinants of new wavefront locations in cholinergic atrial fibrillation
T2 - EP-Europace
UR -
UR -
VL - 20
ER -