Medical and Biological Engineering and Computing

, Volume 41, Issue 6, pp 640–645 | Cite as

Frequency dependence of the cardiac threshold to alternating current between 10 Hz and 160 Hz



It is still unclear what fundamental criteria influence the ability of alternating current (AC) to induce ventricular fibrillation (VF) in vivo. As the VF threshold has a bowl-shaped relationship with frequency (showing a minimum threshold at some frequency), similar to the nervous system, one proposed model has assumed that the mechanisms underlying AC stimulation of nerves are at work for VF induction. More recent work has suggested a second approach, whereby a simple RC-like model is sufficient to understand the cardiac AC stimulation threshold's frequency dependence, suggesting that some unarticulated mechanism is at work for VF. The paper directly tests these two models. In 12 intact dogs and 20 intact guinea pigs, DC pulses were used to stimulate AC square and AC sine waves at 10, 20, 40, 80 and 160 Hz. All electrodes were endocardial, with the return electrode being on a paw or thorax. It was found that, for square and sine wave stimulation in both dogs and guinea pigs, the stimulation threshold increased monotonically with frequency from 10 Hz up to 160 Hz (p<0.01 for dogs and guinea pigs). Between 80 and 160 Hz, the AC stimulation threshold doubled, exactly as predicted by an RC model. It was concluded that the AC stimulation threshold is not bowl-shaped and is best understood with an RC model. As the VF threshold does exhibit a bowl-shape with frequency, as opposed to the stimulation threshold which does not, the VF induction frequency dependence must have different origins.


AC leakage currents Ventricular fibrillation Medical device safety 


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  1. AAMI (1993): ‘American National Standard: Safe current limits for electromedical apparatus’ (Arlington, VA, USA, 1993)Google Scholar
  2. Anderson, N. H., andMunson, A. W. (1957): ‘Electrical stimulation of nerves in the skin at audio frequencies’,J. Acous. Soc. Am.,23, pp. 155–159Google Scholar
  3. Antoni, H., Toppler, J., andKrause, H. (1970): ‘Polarization effects of sinusoidal 50-cycle alternating current on membrane potential of mammalian cardiac fibres’,Pflugers Arch.,314, pp. 274–291CrossRefGoogle Scholar
  4. Dalziel, C. F. (1972): ‘Electric shock hazard’,IEEE Spectrum,9, pp. 41–50Google Scholar
  5. Hill, A. (1936): ‘Excitation and accommodation in nerve’,Proc. Roy. Soc. London,B119, pp. 305–354Google Scholar
  6. Hill, A. V., Katz, B., andSolandt, D. Y. (1937): ‘Nerve excitation by alternating current’,Proc. R. Soc. London Series B,121, pp. 74–132Google Scholar
  7. Kugelberg, J. (1976): ‘Electrical induction of ventricular fibrillation in the human heart’,Scand. J. Cardiovasc. Surg.,10, pp. 237–240Google Scholar
  8. Laks, M. M., Arzbaecher, Bailey, J. J., Briller, S., andGeselowitz, D. (1994): ‘Will relaxing safe current limits for electromedical equipment increase hazards to patients?’Circulation,89, pp. 909–910Google Scholar
  9. Laks, M. M., Arzbaecher, R. C., Bailey, J. J., Geselowitz, D. B., andBerson, A. S. (1996): ‘Recommendations for safe current limits for electrocardiographs. A statement of healthcare professionals from the Committee of electrocardiography, AHA’,Circulation,93, pp. 837–839Google Scholar
  10. Laks, M. M., Laks, R., Laks, A., Geselowitz, D., Bailey, J. J., andBerson, A. (2000): ‘Revisiting the question: will relaxing safe current limits for electromedical equipment increase hazards to patients?’Circulation,102, pp. 823–825Google Scholar
  11. Lindemans, F. W., andGon, J. J. D. van derGon (1978):Cardiovasc. Res.,12, pp. 477–485Google Scholar
  12. Malkin, R. A., Guinn, R., andMandrell, T. (2000): ‘Water soluble propofol anesthesia: An effective and inexpensive alternative’,Lab. Animal.,29, pp. 45–47Google Scholar
  13. Malkin, R. A., andHoffmeister, B. K. (2001): ‘Mechanisms by which AC leakage currents cause complete hemodynamic collapse without inducing fibrillation’,J. Cardiovasc. Electrophysiol.,12, pp. 1154–1161CrossRefGoogle Scholar
  14. Reilly, J. P., Freeman, V. T., andLarkin, W. D. (1985): ‘Sensory effects of transient electrical stimulation-evaluation with a neuro-electric model’,IEEE Trans. Biomed. Eng.,32, pp. 1001–1011Google Scholar
  15. Reilly, P. J. (1998): ‘Applied bioelectricity. From electrical stimulation to electrophysiology’ (New York, New York, 1998)Google Scholar
  16. Roy, O. Z., Park, G. C., andScott, J. R. (1977): ‘Intracardiac catheter fibrillation thresholds as a function of the duration of 60 Hz current and electrode area’,IEEE Trans. Biomed. Eng.,24, pp. 430–435Google Scholar
  17. Swerdlow, C. D., Olson, W. H., O'Connor, M. E., Gallik, D. M., Malkin, R. A., andLaks, M. (1999): ‘Cardiovascular collapse caused by electrocardiographically silent 60-Hz intracardiac leakage current. Implications for electrical safety’,Circulation,99, pp. 2559–2564Google Scholar
  18. Vigmond, E., Malkin, R., andTrayanova, N. (2001): ‘Excitation of a cardiac muscle fiber by extracellularly applied sinusoidal current’,J. Cardiovasc. Electrophys.,12, pp. 1145–1153Google Scholar
  19. Weirich, J., Hohnloser, S., andAntoni, H. (1983): ‘Factors determining the susceptibility of the isolated guinea pig heart to ventricular fibrillation induced by sinusoidal alternating current at frequencies from 1 to 1000 Hz’,Basic Res. Cardiol.,78, 604–616CrossRefGoogle Scholar

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© IFMBE 2003

Authors and Affiliations

  1. 1.Joint Program in Biomedical EngineeringUniversity of Memphis and University of Tennessee-MemphisUSA

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