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 = {Handa, B and Li, X and Aras, KK and Qureshi, NA and Mann, I and Chowdhury, R and Whinnett, ZI and Linton, NWF and Lim, PB and Kanagaratnam, P and Efimov, IR and Peters, N and Ng, FS},
doi = {10.1161/CIRCEP.119.008237},
journal = {Circulation: Arrhythmia and Electrophysiology},
pages = {258--273},
title = {Granger causality-based analysis for classification of fibrillation mechanisms and localisation of rotational drivers},
url = {},
volume = {12},
year = {2020}

RIS format (EndNote, RefMan)

AB - Background:The mechanisms sustaining myocardial fibrillation remain disputed, partly due to a lack of mapping tools that can accurately identify the mechanism with low spatial resolution clinical recordings. Granger causality (GC) analysis, an econometric tool for quantifying causal relationships between complex time-series, was developed as a novel fibrillation mapping tool and adapted to low spatial resolution sequentially acquired data.Methods:Ventricular fibrillation (VF) optical mapping was performed in Langendorff-perfused Sprague-Dawley rat hearts (n=18), where novel algorithms were developed using GC-based analysis to (1) quantify causal dependence of neighboring signals and plot GC vectors, (2) quantify global organization with the causality pairing index, a measure of neighboring causal signal pairs, and (3) localize rotational drivers (RDs) by quantifying the circular interdependence of neighboring signals with the circular interdependence value. GC-based mapping tools were optimized for low spatial resolution from downsampled optical mapping data, validated against high-resolution phase analysis and further tested in previous VF optical mapping recordings of coronary perfused donor heart left ventricular wedge preparations (n=12), and adapted for sequentially acquired intracardiac electrograms during human persistent atrial fibrillation mapping (n=16).Results:Global VF organization quantified by causality pairing index showed a negative correlation at progressively lower resolutions (50% resolution: P=0.006, R2=0.38, 12.5% resolution, P=0.004, R2=0.41) with a phase analysis derived measure of disorganization, locations occupied by phase singularities. In organized VF with high causality pairing index values, GC vector mapping characterized dominant propagating patterns and localized stable RDs, with the circular interdependence value showing a significant difference in driver versus nondriver regions (0.91±0.05 versus 0.35±0.06, P=0.0002).
AU - Handa,B
AU - Li,X
AU - Aras,KK
AU - Qureshi,NA
AU - Mann,I
AU - Chowdhury,R
AU - Whinnett,ZI
AU - Linton,NWF
AU - Lim,PB
AU - Kanagaratnam,P
AU - Efimov,IR
AU - Peters,N
AU - Ng,FS
DO - 10.1161/CIRCEP.119.008237
EP - 273
PY - 2020///
SN - 1941-3084
SP - 258
TI - Granger causality-based analysis for classification of fibrillation mechanisms and localisation of rotational drivers
T2 - Circulation: Arrhythmia and Electrophysiology
UR -
UR -
UR -
VL - 12
ER -