title: Analysis of QRS-T subtraction in unipolar atrial fibrillation electrograms.
abstract: This paper presents a QRS-T subtraction approach for atrial fibrillation (AF) intracardiac atrial electrograms (AEG). It also presents a comparison between the proposed method and two alternative ventricular subtraction techniques: average beat subtraction (ABS) using a fixed length window and an approach based on flat interpolation for QRS cancellation. Areas of the atrium close to the mitral valve showed stronger ventricular influence on the AEGs when compared with the remaining atrial regions. Ventricular influence affects the spectral power distribution of the AEG and can also affect the estimation of the dominant frequency unless the whole ventricular activity influence (QRS-T) is removed. The average power after QRS-T subtraction is significantly reduced for frequencies above 10 Hz (mostly associated with QRS complexes), as well as for frequencies between 3 and 5.5 Hz, (mostly related to T waves). The results indicate that the proposed approach removes ventricular influence on the AF AEGs better than the QRS cancellation method. Spectral analysis showed that both the ABS and the proposed method do well and no method should be preferred to the other. In the time domain, the proposed approach is matched to the lengths and timings of onset and offset for individual QRS-T segments while the ABS approach uses an arbitrary length around the QRS for the pattern used for QRS-T removal.
authors.affiliation: Department of Engineering, Bioengineering Group, University of Leicester, Leicester, UK, jl279@le.ac.uk.
authors.forename: J L
authors.initials: JL
authors.lastname: Salinet
authors.forename: J P V
authors.initials: JP
authors.lastname: Madeiro
authors.forename: P C
authors.initials: PC
authors.lastname: Cortez
authors.forename: P J
authors.initials: PJ
authors.lastname: Stafford
authors.forename: G André
authors.initials: GA
authors.lastname: Ng
authors.forename: G
authors.initials: G
authors.lastname: André Ng
authors.forename: F S
authors.initials: FS
authors.lastname: Schlindwein
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000503:physiopathology*; D004562:Electrocardiography / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted
references.citation: Mayo Clin Proc. 2009 Jul;84(7):643-62
references.pmid: 19567719
references.citation: J Am Coll Cardiol. 2006 Aug 1;48(3):485-91
references.pmid: 16875973
references.citation: J Electrocardiol. 2003 Jul;36(3):243-9
references.pmid: 12942487
references.citation: Circulation. 2006 Aug 15;114(7):e257-354
references.pmid: 16908781
references.citation: Med Biol Eng Comput. 1983 Sep;21(5):538-47
references.pmid: 6633003
references.citation: J Cardiovasc Electrophysiol. 2009 Jan;20(1):123-6
references.pmid: 18803565
references.citation: Circulation. 1998 Sep 1;98(9):887-98
references.pmid: 9738644
references.citation: Circulation. 1999 Apr 13;99(14):1906-13
references.pmid: 10199890
references.citation: IEEE Eng Med Biol Mag. 2006 Nov-Dec;25(6):15-23
references.pmid: 17220131
references.citation: Circulation. 1999 Feb 16;99(6):829-35
references.pmid: 9989971
references.citation: Circulation. 1997 Feb 4;95(3):572-6
references.pmid: 9024141
references.citation: Med Biol Eng Comput. 2011 Nov;49(11):1321-8
references.pmid: 21959592
references.citation: IEEE Trans Biomed Eng. 2006 Dec;53(12 Pt 1):2544-52
references.pmid: 17153212
references.citation: IEEE Trans Biomed Eng. 1998 Feb;45(2):229-34
references.pmid: 9473845
references.citation: Heart Rhythm. 2006 Jan;3(1):120-3
references.pmid: 16399067
references.citation: Med Eng Phys. 2012 Nov;34(9):1236-46
references.pmid: 22226589
references.citation: Nat Rev Cardiol. 2011 Feb;8(2):67-8
references.pmid: 21270842
references.citation: Circulation. 1985 Nov;72(5):1028-36
references.pmid: 4042292
references.citation: Circulation. 2005 Aug 9;112(6):789-97
references.pmid: 16061740