title: A nonparametric surrogate-based test of significance for T-wave alternans detection.
abstract: We present a nonparametric adaptive surrogate test that allows for the differentiation of statistically significant T-wave alternans (TWA) from alternating patterns that can be solely explained by the statistics of noise. The proposed test is based on estimating the distribution of noise-induced alternating patterns in a beat sequence from a set of surrogate data derived from repeated reshuffling of the original beat sequence. Thus, in assessing the significance of the observed alternating patterns in the data, no assumptions are made about the underlying noise distribution. In addition, since the distribution of noise-induced alternans magnitudes is calculated separately for each sequence of beats within the analysis window, the method is robust to data nonstationarities in both noise and TWA. The proposed surrogate method for rejecting noise was compared to the standard noise-rejection methods used with the spectral method (SM) and the modified moving average (MMA) techniques. Using a previously described realistic multilead model of TWA and real physiological noise, we demonstrate the proposed approach that reduces false TWA detections while maintaining a lower missed TWA detection, compared with all the other methods tested. A simple averaging-based TWA estimation algorithm was coupled with the surrogate significance testing and was evaluated on three public databases: the Normal Sinus Rhythm Database, the Chronic Heart Failure Database, and the Sudden Cardiac Death Database. Differences in TWA amplitudes between each database were evaluated at matched heart rate (HR) intervals from 40 to 120 beats per minute (BPM). Using the two-sample Kolmogorov-Smirnov test, we found that significant differences in TWA levels exist between each patient group at all decades of HRs. The most-marked difference was generally found at higher HRs, and the new technique resulted in a larger margin of separability between patient populations than when the SM or MMA were applied to the same data.
authors.affiliation: Massachusetts Institute of Technology, Cambridge, MA 02139, USA. shamim@mit.edu
authors.forename: Shamim
authors.initials: S
authors.lastname: Nemati
authors.forename: Omar
authors.initials: O
authors.lastname: Abdala
authors.forename: Violeta
authors.initials: V
authors.lastname: Monasterio
authors.forename: Susie
authors.initials: S
authors.lastname: Yim-Yeh
authors.forename: Atul
authors.initials: A
authors.lastname: Malhotra
authors.forename: Gari D
authors.initials: GD
authors.lastname: Clifford
mesh_terms: D003198:Computer Simulation; D016208:Databases, Factual; D004562:Electrocardiography / Q000379:methods*; D006801:Humans; D008955:Models, Cardiovascular; D012815:Signal Processing, Computer-Assisted; D018709:Statistics, Nonparametric
references.citation: IEEE Trans Biomed Eng. 2006 Apr;53(4):701-11
references.pmid: 16602577
references.citation: Circulation. 2000 Jun 13;101(23):E215-20
references.pmid: 10851218
references.citation: IEEE Trans Biomed Eng. 2003 Mar;50(3):289-94
references.pmid: 12669985
references.citation: J Appl Physiol (1985). 2002 Feb;92(2):541-9
references.pmid: 11796662
references.citation: Physiol Meas. 2010 May;31(5):595-609
references.pmid: 20308774
references.citation: IEEE Trans Biomed Eng. 2005 Apr;52(4):599-613
references.pmid: 15825862
references.citation: Am J Cardiol. 2002 Jan 1;89(1):79-82
references.pmid: 11779531
references.citation: J Am Coll Cardiol. 2009 Feb 10;53(6):471-9
references.pmid: 19195603
references.citation: Indian Pacing Electrophysiol J. 2003 Apr 01;3(2):67-73
references.pmid: 16943959
references.citation: Pacing Clin Electrophysiol. 2007 Mar;30(3):352-8
references.pmid: 17367354
references.citation: Pacing Clin Electrophysiol. 2009 May;32(5):632-41
references.pmid: 19422585
references.citation: Circulation. 2004 Oct 5;110(14):1885-9
references.pmid: 15451804
references.citation: J Am Coll Cardiol. 2002 Jul 17;40(2):207-17
references.pmid: 12106921
references.citation: Ann Biomed Eng. 2008 Sep;36(9):1558-64
references.pmid: 18618261
references.citation: Anadolu Kardiyol Derg. 2007 Jul;7 Suppl 1:116-9
references.pmid: 17584701
references.citation: Circulation. 1988 Jan;77(1):110-21
references.pmid: 3335062
references.citation: Comput Cardiol. 2008 Sep 14;2008:509-512
references.pmid: 20798786
references.citation: Lancet. 2003 Jul 12;362(9378):125-6
references.pmid: 12867114
references.citation: Am J Physiol Heart Circ Physiol. 2000 Sep;279(3):H1248-55
references.pmid: 10993791