Advertisement

Non-invasive Wedensky modulation within the QRS complex

  • K. Hnatkova
  • S. J. Ryan
  • J. Bathen
  • H. H. Hoium
  • M. Malik
Article

Abstract

To investigate non-invasively induced Wedensky modulation, 2 ms pulses of 5, 20 and 40 mA were delivered between precordial and subscapular patches synchronously with the QRS complex. Wavelet vector magnitude was obtained for averaged modulated and non-modulated complexes. The surface area of a 3D-envelope of their difference (WSR) was compared in 59 patients with an uncomplicated follow-up after myocardial infarction (MI) (42 men, 64.3±9.1 years), in 30 patients with ischaemic heart disease and a history of ventricular tachycardia/fibrillation (VT/VF) (29 men, 63.1±9.8 years), and in 53 healthy subjects (control) (22 men, 56.6±10.1 years). Reproducibility of the assessment was tested by computing relative errors in a sub-population of 30 VT/VF patients and 47 controls. Wedensky modulation parameters differed significantly between control, MI and VT/VF subjects. In 10 ms post-modulation windows, the following WSR values were obtained: controls: 1184±496 (5 mA), 1553±838 (20 mA) and 2092±1488 (40 mA); VT/VF: 861±412 (5 mA), 1134±636 (20 mA) and 1320±1036 (40 mA); MI: 1305±885 (5 mA) and 1779±1169 (20 mA). With all modulating energies used, the VT/VF patients differed significantly from both the controls and MI patients; control patients against VT/VF patients: p<0.004 (5 mA), p<0.01 (20 mA) and p<0.001 (40 mA); VT/VF patients against MI patients: p<0.02 (5 mA), p<0.01 (20 mA); control patients against MI patients: all p=NS. The reproducibility assessment showed an acceptable stability of Wedensky modulation parameters. This study demonstrated that wavelet decomposition detects non-invasive Wedensky modulation within the QRS complex, and VT/VF patients are less sensitive to Wedensky modulation than control and MI patients.

Keywords

Wedensky modulation Ventricular tachycardia Myocardial infarction Signal averaged electrocardiogram Wavelet decomposition 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Antzelevitch, C., Bernstein, M. J., Feldman, H. N., andMoe, G. K. (1983): ‘Parasystole, reentry, and tachycardia: a canine preparation of cardiac arrhythmias occuring across inexcitable segments of tissue’,Circulation,68, pp. 1101–1115Google Scholar
  2. Bigger, J. T. (1997): ‘Prophylactic use of implanted cardiac defibrillators in patients at high risk for ventricular arrhythmias after coronary-artery bypass graft surgery. Corronary Artery Bypass Graft (CABG) Patch Trial Investigators’,N. Engl. J. Med.,337, pp. 1569–1575CrossRefGoogle Scholar
  3. Binah, O., andRosen, M. R. (1992): ‘Mechanism of ventricular arrhythmias’,Circulation,85, pp. 125–131Google Scholar
  4. Castellanos, A., Jr, Lemberg, L., Johnson, D., andBerkovitz, B. V. (1966): ‘The Wedensky effect in the human heart’,Brit. Heart. J.,28, pp. 276–283Google Scholar
  5. Combes, J. M., Grossman, A., andTchamitchian, P. (Eds.) (1988): ‘Wavelets, time-frequency methods and phase space’ (Springer-Verlag, Berlin, 1988)Google Scholar
  6. Chui, C. K. (1992): ‘An introduction to wavelets’ (Academic Press, San Diego)zbMATHGoogle Scholar
  7. Goldenberg, M., andRothberger, C. J. (1933): ‘Untersuchungen an der spezifischen Muskulatur des Hundeherzens’,Z. ges. Exp. Me.,90, p. 508Google Scholar
  8. Gray, R. A., Jalife, J., Panfilov, A., Baxter, W. T., Cabo, C., Davidenko, J. M., andPertsov, A. M. (1995): ‘Nonstationary vortex-like reentrant activity as a mechanism of polymorphic ventricular tachycardia in the isolated rabbit heart’,Circulation,91, pp. 2454–2469Google Scholar
  9. Grossman, A., andMorlet, J. (1984): ‘Decomposition of Hardy functions into a square integrable wavelets of constant shape’,SIAM J. Math.,15, pp. 723–736CrossRefGoogle Scholar
  10. Hnatkova, K., Malik, M., Kulakowski, P., andCamm, A. J. (2000a): ‘Wavelet analysis of signal averaged electrocardiograms: I. Design, clinical assessment and reproducibility of the method’,Ann. Noninvasive Electrocardiol.,5, pp. 4–19CrossRefGoogle Scholar
  11. Hnatkova, K., Ryan, S. J., Hoium, H. H., andMalik, M. (2000b): ‘Noninvasive assessment of Wedensky modulated signal-averaged electrocardiograms’,Pacing Clin. Electrophysiol.,23, pp. 1977–1980Google Scholar
  12. Hoffman, B. F., andRosen, M. R. (1981): ‘Cellular mechanism for cardiac arrhythmias’,Circ. Res.,49, pp. 1–15Google Scholar
  13. Hoium, H. H., Brewer, J. E., Kroll, K. C., Kroll, M. W., andKroll, K. J. (1994): ‘Use of subthreshold transcutaneous biasing as a possible prognostic test for ventricular tachycardia’,RBM 3/4,16, pp. 111–115Google Scholar
  14. Kronland-Martinet, P., Morlet, J., andGrossmann, A. (1987): ‘Analysis of sound patterns through wavelet transform’,Int. J. Pattern Recognit. Artifi. Intell.,1, pp. 273–302CrossRefGoogle Scholar
  15. Kulakowski, P. (1999): ‘Ventricular signal averaging: Is it completely dead?’,Cardiac Electrophysiol. Rev.,3, pp. 264–268CrossRefGoogle Scholar
  16. Malik, M., Odemuyiwa, O., Poloniecki, J., Kulakowski, P., Farrell, T., Staunton, A., andCamm, A. J. (1992): ‘Late potentials after acute myocardial infarction—Performance of different criteria for the prediction of arrhythmic complications’,Europ. Heart J.,13, pp. 599–607Google Scholar
  17. Malik, M., Benditt, D. G., Hnatkova, K., Hegrenaes, L., Ryan, J., Munger, T. M., Samniah, N., Bathen, J., Kroll, M. W., Hoium, H., andStanton, M. S. (1999): ‘External cardiac modulation: Evidence of Wedensky phenomenon in healthy subjects and ventricular tachycardia patients’, XXIst Congress of the European Society of Cardiology,Europ. Heart J.,20, p. 311CrossRefGoogle Scholar
  18. Morlet, D., Peyrin, F., Desseigne, P., Touboul, P., andRubel, P. (1993): ‘Wavelet analysis of high-resolution signal-averaged ECGs in postinfarction patients’,J. Electrocardiol.,26, pp. 311–320CrossRefGoogle Scholar
  19. Morlet, D., Couderc, P. J., Toboul, P., andRubel, P. (1995): ‘Wavelet analysis of high-resolution ECGs in post-infarction patients: role of the basic wavelet and of the analyzed lead’,Int. J. Biomed. Comput.,39, pp. 311–325CrossRefGoogle Scholar
  20. Olsson, S. B. (1984): ‘Pathophysiology of re-entrant dysrhythmias’,Europ. Heart. J. (suppl. B), pp. 19–23Google Scholar
  21. Scherf, D., andSchott, A. (1953): ‘Extrasystoles and allied arrhythmias’, (William Heinemann, London, 1953), pp. 999–1030Google Scholar
  22. Simson, M. B. (1981): ‘Use of signals in the terminal QRS complex to identify patients with ventricular tachycardia after myocardial infarction’,Circulation,64, pp. 235–242Google Scholar
  23. Wedensky, N. E. (1887): ‘Über die Beziehung zwischen Reizung und Erregung im Tetanus’, Vol. 54 (Ber. Acad. Wiss, St Petersburg, 1887), p. 96Google Scholar
  24. Wedensky, N. E. (1903): ‘Die Erregung, Hemmung und Narkose’,Pflügers Arch. Ges. Physiol. 100, pp. 1–9CrossRefGoogle Scholar

Copyright information

© IFMBE 2002

Authors and Affiliations

  • K. Hnatkova
    • 1
  • S. J. Ryan
    • 2
  • J. Bathen
    • 3
  • H. H. Hoium
    • 2
  • M. Malik
    • 1
  1. 1.Department of Cardiological SciencesSt George's Hospital Medical SchoolLondonUK
  2. 2.Harbinger Medical Inc.MinneapolisUSA
  3. 3.Regional HospitalTrondheimNorway

Personalised recommendations