Coherence as a measure of noise in the ECG

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Johmmes J. Struijk, Claus Graff, Jørgen K. Kanters, Joel Q. Xue, Ask Schou Jensen, Samuel Schmidt

The 12-lead ECG can be described as the projection of a time-varying dipole on the lead vectors. This dipole-source assumption implies that the different leads must show a high coherence and that deviations from values close to unity may indicate the presence of noise. We evaluated the average coherence in the band of 5 Hz to 45 Hz in 309 ECGs and compared the coherence measure with an automatic out-of-band noise evaluation, quantified at a scale from 0 (clean) to 10 (very noisy). The generalized magnitude squared coherence (GMSC), which is a global measure of the linear relationships among the leads, was used. A high coherence (GMSC> 0. 95) was always associated with very low noise (level 0 or 1) and 0.9 2 the GMSC was <0.87 in all cases. There were no cases of high noise level and a high coherence, however, in 32% of the cases with noise level 0 or 1 the GMSC was <0.8. For low-noise ECGs the GMSC is close to unity, with a good correlation between noise level and GMSC for normal ECGs. However, a low coherence also seems to be associated with abnormalities in the ECG, which will be subject for further study.

Original languageEnglish
Article number7042973
JournalComputing in Cardiology
Volume41
Issue numberJanuary
Pages (from-to)37-40
Number of pages4
ISSN2325-8861
Publication statusPublished - 1 Jan 2014
Event41st Computing in Cardiology Conference, CinC 2014 - Cambridge, United States
Duration: 7 Sep 201410 Sep 2014

Conference

Conference41st Computing in Cardiology Conference, CinC 2014
CountryUnited States
CityCambridge
Period07/09/201410/09/2014
Sponsoret al., IEEE/EMBS, Massachusetts Institute of Technology (MiT), Mortara, Philips, PhysioNet

ID: 204298447