Spatial characteristics of atrial fibrillation using the surface ECG
(2007) Computers in Cardiology, 2007 In Computers in Cardiology 34. p.273276 Abstract
 The present study investigates spatial properties of atrial fibrillation (AF) by analyzing VCG loops synthesized from 12lead ECGs. During intervals with ventricular activity, the atrial signal is extracted using spatiotemporal QRST cancellation, thus making continuous fwave analysis possible. Spatial properties are characterized through joint analysis of successive fixedlength signal segments, either of 1s length or related to the typical length of an fwave. The spatial properties are expressed in terms of loop orientation, i.e., angles of azimuth and elevation, as well as in morphologic terms such as planarity and planar geometry of the loops and related temporal variability. Several parameters have been suggested to characterize the... (More)
 The present study investigates spatial properties of atrial fibrillation (AF) by analyzing VCG loops synthesized from 12lead ECGs. During intervals with ventricular activity, the atrial signal is extracted using spatiotemporal QRST cancellation, thus making continuous fwave analysis possible. Spatial properties are characterized through joint analysis of successive fixedlength signal segments, either of 1s length or related to the typical length of an fwave. The spatial properties are expressed in terms of loop orientation, i.e., angles of azimuth and elevation, as well as in morphologic terms such as planarity and planar geometry of the loops and related temporal variability. Several parameters have been suggested to characterize the degree of AF organization from electrogram analysis, but only a few parameters for noninvasive, ECGbased characterization of which AF frequency is the most studied. This parameter is related to atrial refractoriness and reflects AF organization. In the present study, the significance of spatial (loop morphology) parameters is studied in relation to AF frequency, hypothesizing that more organized AF, being expressed by a lower frequency, is associated with decreased variability in loop morphology. A total of 26 patients with chronic AF were analyzed with respect to spatial properties, using 60s ECG recordings. For the database AF frequency ranged from 3.9 to 7.7 Hz, with a mean of 6.4±1.0 Hz (mean±std). The results showed that loop orientation can be determined from global analysis (i.e., the entire 60s segment was used for determining the two angles) or the mean of segmentbased analysis, both types of analysis leading to similar results. The hypothesis that more organized AF is associated with decreased variability in loop morphology was to some extent confirmed for the parameters planarity and planar geometry; for 1s segments, the correlation to AF frequency was 0.608 (p<0.001) and 0.543 (p<0.005). This finding also applied to segment lengths related to fwave duration. In conclusion, the simpler analysis based on 1s segments may be preferred since it does not require fwave delineation. Global analysis and the mean of segmentbased analysis (1s segments) showed increased planarity and decreased planar geometry for lower AF frequencies, possibly related to higher similarity of successive loops in more organized AF. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/601627
 author
 Richter, Ulrike ^{LU} ; Stridh, Martin ^{LU} ; Bollmann, Andreas ^{LU} ; Husser, Daniela and Sörnmo, Leif ^{LU}
 organization
 publishing date
 2007
 type
 Chapter in Book/Report/Conference proceeding
 publication status
 published
 subject
 in
 Computers in Cardiology
 volume
 34
 pages
 273  276
 conference name
 Computers in Cardiology, 2007
 external identifiers

 WOS:000264173100069
 Scopus:62949125362
 ISSN
 02766574
 ISBN
 9781424425334
 DOI
 10.1109/CIC.2007.4745474
 language
 English
 LU publication?
 yes
 id
 e33a92507759496598169df65d277922 (old id 601627)
 date added to LUP
 20071211 10:29:46
 date last changed
 20170101 07:44:41
@inproceedings{e33a92507759496598169df65d277922, abstract = {The present study investigates spatial properties of atrial fibrillation (AF) by analyzing VCG loops synthesized from 12lead ECGs. During intervals with ventricular activity, the atrial signal is extracted using spatiotemporal QRST cancellation, thus making continuous fwave analysis possible. Spatial properties are characterized through joint analysis of successive fixedlength signal segments, either of 1s length or related to the typical length of an fwave. The spatial properties are expressed in terms of loop orientation, i.e., angles of azimuth and elevation, as well as in morphologic terms such as planarity and planar geometry of the loops and related temporal variability. Several parameters have been suggested to characterize the degree of AF organization from electrogram analysis, but only a few parameters for noninvasive, ECGbased characterization of which AF frequency is the most studied. This parameter is related to atrial refractoriness and reflects AF organization. In the present study, the significance of spatial (loop morphology) parameters is studied in relation to AF frequency, hypothesizing that more organized AF, being expressed by a lower frequency, is associated with decreased variability in loop morphology. A total of 26 patients with chronic AF were analyzed with respect to spatial properties, using 60s ECG recordings. For the database AF frequency ranged from 3.9 to 7.7 Hz, with a mean of 6.4±1.0 Hz (mean±std). The results showed that loop orientation can be determined from global analysis (i.e., the entire 60s segment was used for determining the two angles) or the mean of segmentbased analysis, both types of analysis leading to similar results. The hypothesis that more organized AF is associated with decreased variability in loop morphology was to some extent confirmed for the parameters planarity and planar geometry; for 1s segments, the correlation to AF frequency was 0.608 (p<0.001) and 0.543 (p<0.005). This finding also applied to segment lengths related to fwave duration. In conclusion, the simpler analysis based on 1s segments may be preferred since it does not require fwave delineation. Global analysis and the mean of segmentbased analysis (1s segments) showed increased planarity and decreased planar geometry for lower AF frequencies, possibly related to higher similarity of successive loops in more organized AF.}, author = {Richter, Ulrike and Stridh, Martin and Bollmann, Andreas and Husser, Daniela and Sörnmo, Leif}, booktitle = {Computers in Cardiology}, isbn = {9781424425334}, issn = {02766574}, language = {eng}, pages = {273276}, title = {Spatial characteristics of atrial fibrillation using the surface ECG}, url = {http://dx.doi.org/10.1109/CIC.2007.4745474}, volume = {34}, year = {2007}, }