Noise processing in exercise ECG stress test for the analysis and the clinical characterization of QRS and T wave alternans

Abstract The aim of this study is to analyze different sources of noise in ECG recordings from stress tests in order to obtain reliable parameters and measurements for the analysis of T-wave and QRS-complex alternans (TWA & QRSA). Simple methods for eliminating common sources of noise like power-line interference, baseline drift and electromyographic noise were used. The pre-processing phase considered the detection of steep slope/spike, low amplitude signal, and flat line or missing lead artefacts. The detection of TWA and QRSA was based on Principal Component Analysis indices and wave amplitudes considering all the leads. A particular database of 106 ECG records during stress testing was considered. The signal quality analysis performed in this study has permitted to obtain reliable and noise-tolerant measurements of TWA and QRSA indices. The different diagnostic groups were used for the evaluation of the clinical significance of the alternans. Men have significantly higher values of QRSA than women. Smokers have significantly higher TWA values as compared with non-smokers. Significant negative correlation was obtained between age and both TWA and QRSA. Correlations between TWA and QRSA and the double product of arterial hypertension and the maximal heart rate during the stress test were statistically significant, positive and relatively strong.

[1]  Rémi Dubois,et al.  T‐Wave Morphology Parameters Based on Principal Component Analysis Reproducibility and Dependence on T−Offset Position , 2007, Annals of noninvasive electrocardiology : the official journal of the International Society for Holter and Noninvasive Electrocardiology, Inc.

[2]  M R Gold,et al.  Effect of Heart Rate on T Wave Alternans , 1997, Journal of cardiovascular electrophysiology.

[3]  A Catizone,et al.  [Electric alternans of QRS: its electrophysiologic significance in narrow QRS supraventricular paroxysmal tachycardia]. , 1992, Minerva cardioangiologica.

[4]  M. Cutler,et al.  Explaining the clinical manifestations of T wave alternans in patients at risk for sudden cardiac death. , 2009, Heart rhythm.

[5]  M. Das,et al.  Fragmented QRS and other depolarization abnormalities as a predictor of mortality and sudden cardiac death , 2010, Current opinion in cardiology.

[6]  I. Christov,et al.  Q-onset and T-end delineation: assessment of the performance of an automated method with the use of a reference database , 2007, Physiological measurement.

[7]  Philippe Maury,et al.  Alternans in QRS Amplitude During Ventricular Tachycardia , 2002, Pacing and clinical electrophysiology : PACE.

[8]  Takanori Ikeda,et al.  T-wave alternans as a predictor for sudden cardiac death after myocardial infarction. , 2002, The American journal of cardiology.

[9]  I. Christov,et al.  Filtering of electromyogram artifacts from the electrocardiogram. , 1999, Medical engineering & physics.

[10]  I.I. Christov,et al.  Principal Component Analysis for detection and assessment of T-wave alternans , 2008, 2008 Computers in Cardiology.

[11]  I Christov,et al.  Low frequency distortions of the electrocardiogram. , 1997, Medical engineering & physics.

[12]  R J Cohen,et al.  Electrical alternans and cardiac electrical instability. , 1988, Circulation.

[13]  L. Y. Di Marco,et al.  An algorithm for assessment of quality of ECGs acquired via mobile telephones , 2011, 2011 Computing in Cardiology.

[14]  Ivaylo I Christov,et al.  Real time electrocardiogram QRS detection using combined adaptive threshold , 2004, Biomedical engineering online.

[15]  Berson As.  Comments on "recommendations for standardization of instruments in electrocardiography and vectorcardiography". , 1968 .

[16]  C Zywietz,et al.  European Conformance Testing Services for computerized electrocardiography. New procedures and standards. , 1993, Journal of electrocardiology.

[17]  G Bortolan,et al.  T-wave alternans detection by a combined method of principal component analysis and T-wave amplitude. , 2012, Physiological measurement.

[18]  Chavdar Levkov,et al.  Removal of power-line interference from the ECG: a review of the subtraction procedure , 2005, Biomedical engineering online.

[19]  S. Hohnloser,et al.  Predictive value of T-wave alternans for arrhythmic events in patients with congestive heart failure , 2000, The Lancet.

[20]  F. Morady,et al.  Significance of QRS Alternans During Narrow QRS Tachycardias , 1991, Pacing and clinical electrophysiology : PACE.

[21]  R. Cohen,et al.  Simple finite-element model accounts for wide range of cardiac dysrhythmias. , 1984, Proceedings of the National Academy of Sciences of the United States of America.

[22]  Arthur A M Wilde,et al.  Microvolt T-wave alternans during exercise and pacing are not comparable. , 2009, Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology.

[23]  J. Ruskin,et al.  Electrical alternans and vulnerability to ventricular arrhythmias. , 1994, The New England journal of medicine.

[24]  Giovanni Bortolan,et al.  Dynamic filtration of high-frequency noise in ECG signal , 2014, Computing in Cardiology 2014.

[25]  F M Charbonnier,et al.  AAMI/ANSI standard for automatic or advisory external defibrillators. Association for the Advancement of Medical Instrumentation. American National Standards Institute. , 1993, Journal of electrocardiology.

[26]  G. Bortolan,et al.  T wave and QRS complex alternans during standard diagnostic stress ECG test , 2010, 2010 Computing in Cardiology.

[27]  I.K. Duskalov,et al.  Developments in ECG acquisition, preprocessing, parameter measurement, and recording , 1998, IEEE Engineering in Medicine and Biology Magazine.

[28]  Ch. L. Levkov,et al.  Fast integer coefficient FIR filters to remove the AC interference and the high-frequency noise components in biological signals , 1989, Medical and Biological Engineering and Computing.

[29]  A. Savitzky,et al.  Smoothing and Differentiation of Data by Simplified Least Squares Procedures. , 1964 .

[30]  I. K. Daskalov,et al.  Subtraction of 50 Hz interference from the electrocardiogram , 2006, Medical and Biological Engineering and Computing.