Sequential algorithm for life threatening cardiac pathologies detection based on mean signal strength and EMD functions.
BACKGROUND
Ventricular tachycardia (VT) and ventricular fibrillation (VF) are the most serious cardiac arrhythmias that require quick and accurate detection to save lives. Automated external defibrillators (AEDs) have been developed to recognize these severe cardiac arrhythmias using complex algorithms inside it and determine if an electric shock should in fact be delivered to reset the cardiac rhythm and restore spontaneous circulation. Improving AED safety and efficacy by devising new algorithms which can more accurately distinguish shockable from non-shockable rhythms is a requirement of the present-day because of their uses in public places.


METHODS
In this paper, we propose a sequential detection algorithm to separate these severe cardiac pathologies from other arrhythmias based on the mean absolute value of the signal, certain low-order intrinsic mode functions (IMFs) of the Empirical Mode Decomposition (EMD) analysis of the signal and a heart rate determination technique. First, we propose a direct waveform quantification based approach to separate VT plus VF from other arrhythmias. The quantification of the electrocardiographic waveforms is made by calculating the mean absolute value of the signal, called the mean signal strength. Then we use the IMFs, which have higher degree of similarity with the VF in comparison to VT, to separate VF from VTVF signals. At the last stage, a simple rate determination technique is used to calculate the heart rate of VT signals and the amplitude of the VF signals is measured to separate the coarse VF from VF. After these three stages of sequential detection procedure, we recognize the two components of shockable rhythms separately.


RESULTS
The efficacy of the proposed algorithm has been verified and compared with other existing algorithms, e.g., HILB 1, PSR 2, SPEC 3, TCI 4, Count 5, using the MIT-BIH Arrhythmia Database, Creighton University Ventricular Tachyarrhythmia Database and MIT-BIH Malignant Ventricular Arrhythmia Database. Four quality parameters (e.g., sensitivity, specificity, positive predictivity, and accuracy) were calculated to ascertain the quality of the proposed and other comparing algorithms. Comparative results have been presented on the identification of VTVF, VF and shockable rhythms (VF + VT above 180 bpm).


CONCLUSIONS
The results show significantly improved performance of the proposed EMD-based novel method as compared to other reported techniques in detecting the life threatening cardiac arrhythmias from a set of large databases.
Anas
Emran M Abu
EM
Department of Electrical and Electronic Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh.
Lee
Soo Y
SY
Hasan
Md K
MK
D000465:Algorithms; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000503:physiopathology; D047548:Defibrillators; D003937:Diagnosis, Differential; D004562:Electrocardiography; D006801:Humans; D012815:Signal Processing, Computer-Assisted; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000503:physiopathology
Physiol Meas. 2002 Nov;23(4):629-34
12450264
IEEE Trans Biomed Eng. 1996 Nov;43(11):1120-5
9214830
Physiol Meas. 2004 Oct;25(5):1167-78
15535182
Med Biol Eng Comput. 1987 May;25(3):241-9
3329694
Med Instrum. 1976 May-Jun;10(3):163-7
1272092
Resuscitation. 2009 Nov;80(11):1301-7
19735967
IEEE Trans Biomed Eng. 2007 Jan;54(1):174-7
17260872
Pacing Clin Electrophysiol. 1988 May;11(5):622-31
2456541
Biomed Eng Online. 2005 Oct 27;4:60
16253134
Pacing Clin Electrophysiol. 1988 Nov;11(11 Pt 1):1592-606
2462245
IEEE Trans Biomed Eng. 1999 May;46(5):548-55
10230133
IEEE Trans Biomed Eng. 1991 Jun;38(6):561-70
1879845
Physiol Meas. 2009 Jul;30(7):695-705
19525573
Comput Biol Med. 2009 Nov;39(11):1051-7
19762011
IEEE Trans Biomed Eng. 1990 Sep;37(9):837-43
2227970
IEEE Trans Biomed Eng. 1989 Jun;36(6):618-24
2731947
IEEE Trans Biomed Eng. 1999 Feb;46(2):192-202
9932341
J Biomed Eng. 1989 Jul;11(4):320-8
2755113
Physiol Meas. 2000 Nov;21(4):429-39
11110242
Med Biol Eng Comput. 1993 Mar;31(2):111-7
8331990
IEEE Trans Biomed Eng. 1994 May;41(5):480-7
8070808