A hybrid wavelet and time plane based method for QT interval measurement in ECG signals

Swanirbhar Majumder, Saurabh Pal, Sidhartha Dhar, Abhijit Sinha, Abhijit Roy

Dept of ECE, NERIST (Deemed University), Arunachal Pradesh, India.
Haldia Institute of Technology, Haldia, West Bengal, India..

DOI: 10.4236/jbise.2009.24042                

Abstract

Here we present a method of QT interval meas-urement for Physionet's online QT Challenge ECG database using the combination of wavelet and time plane feature extraction mechanisms. For this we mainly combined two previous works one done using the Daubechies 6 wavelet and one time plane based with modifications in their algorithms and inclusion of two more wavelets (Daubechies 8 and Symlet 6). But found that out of these three wavelets Daube-chies 6 and 8 gives the best output and when averaged with the interval of time plane feature extraction method it gives least percentage of error with respect to the median reference QT interval as specified by Physionet. Our modified time plane feature extraction scheme along with the wavelet method together produces best re-sults for automated QT wave measurement as its regular verification is important for analyzing cardiac health. For the V2 chest lead particularly whose QT wave is of tremendous significance we have tested on 530 recordings of Physionet. This is because delay in cardiac repolarization causes ventricular tachyarrhythmias as well as Torsade de pointes (TdP). A feature of TdP is pronounced prolongation of the QT interval in the supraventricular beat preceding the ar-rhythmia. TdP can degenerate into ventricular fibrillation, leading to sudden death.

Keywords

ECG; QT; Physionet; TdP

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	A. J. Moss, et al., (2001) ISHNE guidelines for electro-cardiographic evaluation of drug-related QT prolongation and other alterations in ventricular repolarisation: Task force summary, Ann Noninvasive Electrocardiol.
[2]	R. J. Myerburg, et al., (2001) Cardiac arrest and sudden death, In: Peter Libby., editor. Braunwald's Heart Disease: A Textbook of Cardiovascular Disease. 6. Saunders (W. B.) Co Ltd, 899-900.
[3]	Haverkamp et al., (2000) The potential for QT prolonga-tion and proarrhythmia by non-antiarrhythmic drugs: Clinical and regulatory implications, European Heart Journal.
[4]	C. M. Pratt, et al., (1996) Dose response relation between terfenidine and the QTc interval on the scalar electrocar-diogram: Distinguishing a drug effect from spontaneous variability, American Heart Journal.
[5]	I. Salvelieva, et al., (1998) Agreement and reproducibil-ity of automatic versus manual measurement of QT in-terval and QT dispersion, Ame J Cardiol., 81, 471-477.
[6]	J. Kautzner, et al., (1994) Short and long-term repro-ducibility of QT, QTc and QT dispersion measurements in healthy subjects, PACE Pacing and Clinical Electro-physiology, 17, 928-940.
[7]	Y. Sun, et al, Characteristic wave detection in ECG sig-nal using morphological transform, BMC Cardiovascular Disorder, 5, 2005.
[8]	Mahmoodabadi, et al., ECG feature extraction using Daubechies wavelets, Proceedings of fifth IASTED In-ternational Conference on Visualization, Imaging and Image Processing, Spain.
[9]	M. Mitra et al, ECG signal processing for analysis of abnormalities based on QT interval-A novel approach, Proceedings of AMSE International Conference on Model-ing and Simulation MS’07, Kolkata, India, 216-218.
[10]	S. Majumder, et al Wavelet and time plane based feature extraction of ECG signal, Proceedings of National Con-ference on Communication & Networking (NCCN’08) Punjab, India, 99-103.
[11]	Reference txt, (2006) Reference QT interval measure-ments used as the basis for calculating final scores in the PhysioNet/Computers in Cardiology Challenge, http:// www.physionet.org.
[12]	P. Laguna et al., (1994) Automatic detection of wave boundaries in multilead ECG signals: validation with the CSE database, Comput Biomed Res, Feb, 27(1), 45-60.
[13]	F. B. Hilderbrand, Introduction to numerical analysis, TMH edn, 82-84.
[14]	A. Sagie, et al., An improved method for adjusting the QT interval for heart rate (the Framingham Heart Study), Am J Cardiol, 70 (7).
[15]	G. S. Wagner, Marriott’s Practical ECG, 10th Edition, Copyright ?2001 Lippincott Williams & Wilkins.
[16]	[16] (2008) A hybrid wavelet and time plane based method for QT interval measurement in ECG dignals, 9th International Conference on Signal Processing, Publication Date: 26-29 Oct., On page(s): 2120-2123, Location: Beijing, China, ISBN: 978-1-4244-2178-7, DOI: 10.1109/ICSP.4697564.