Introducing BisQ, A Bicoherence-Based Nonlinear Index to Explore the Heart Rhythm

TY - JOUR

T1 - Introducing BisQ, A Bicoherence-Based Nonlinear Index to Explore the Heart Rhythm

AU - Hernández-Caceres, José Luis

AU - González-Fernández, René Iván

AU - Ontivero-Ortega, Marlis

AU - Nolte, Guido

N1 - Funding Information: Funding: This research was partially funded by the German Research Foundation (DFG), SFB936/Z3 and TRR 169/C1/B4. Publisher Copyright: © 2020 MDPI AG. All rights reserved. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2020/7

Y1 - 2020/7

N2 - Nonlinear frequency coupling is assessed with bispectral measures, such as bicoherence. In this study, BisQ, a new bicoherence-derived index, is proposed for assessing nonlinear processes in cardiac regulation. To find BisQ, 110 ten-minute ECG traces obtained from 55 participants were initially studied. Via bispectral analysis, a bicoherence matrix (BC) was obtained from each trace (0.06 to 1.8 Hz with a resolution of 0.01 Hz). Each frequency pair in BC was tested for correlation with the HRV recurrent quantification analysis (RQA) index Lmean, obtained from tachograms from the same ECG trace. BisQ is the result of adding BC values corresponding to the three frequency pairs exhibiting the highest correlation with Lmean. BisQ values were estimated for different groups of subjects: Healthy persons, persons with arrhythmia, persons with epilepsy, and preterm neonates. ECG traces from persons with arrhythmia showed no significant differences in BisQ values respect to healthy persons, while persons with epilepsy and neonates showed higher BisQ values (p < 0.05; Mann-Whitney U-test). BisQ reflects nonlinear interactions at the level of sinus-and atrial-ventricular nodes, and most likely cardiorespiratory coupling as well. We expect that BisQ will allow for further exploration of cardiac nonlinear dynamics, complementing available HRV indices.

AB - Nonlinear frequency coupling is assessed with bispectral measures, such as bicoherence. In this study, BisQ, a new bicoherence-derived index, is proposed for assessing nonlinear processes in cardiac regulation. To find BisQ, 110 ten-minute ECG traces obtained from 55 participants were initially studied. Via bispectral analysis, a bicoherence matrix (BC) was obtained from each trace (0.06 to 1.8 Hz with a resolution of 0.01 Hz). Each frequency pair in BC was tested for correlation with the HRV recurrent quantification analysis (RQA) index Lmean, obtained from tachograms from the same ECG trace. BisQ is the result of adding BC values corresponding to the three frequency pairs exhibiting the highest correlation with Lmean. BisQ values were estimated for different groups of subjects: Healthy persons, persons with arrhythmia, persons with epilepsy, and preterm neonates. ECG traces from persons with arrhythmia showed no significant differences in BisQ values respect to healthy persons, while persons with epilepsy and neonates showed higher BisQ values (p < 0.05; Mann-Whitney U-test). BisQ reflects nonlinear interactions at the level of sinus-and atrial-ventricular nodes, and most likely cardiorespiratory coupling as well. We expect that BisQ will allow for further exploration of cardiac nonlinear dynamics, complementing available HRV indices.

KW - Arrhythmia

KW - Bispectrum

KW - Electrocardiogram

KW - Epilepsy

KW - Heart rate variability

KW - Recurrent quantification analysis

UR - http://www.scopus.com/inward/record.url?scp=85092266763&partnerID=8YFLogxK

U2 - 10.3390/MCA25030045

DO - 10.3390/MCA25030045

M3 - SCORING: Journal article

AN - SCOPUS:85092266763

VL - 25

JO - MATH COMPUT APPL

JF - MATH COMPUT APPL

SN - 1300-686X

IS - 3

M1 - 25030045

ER -