Relation between upper limit of vulnerability and defibrillation threshold in humans

Peng Sheng Chen, Gregory K. Feld, Jolene M. Kriett, Morton M. Mower, Riyad Y. Tarazi, R. Peter Fleck, Charles D. Swerdlow, Eli S. Gang, Robert M. Kass

Research output: Contribution to journalArticle

Abstract

Background. In the canine model, an upper limit of shock strength exists that can induce ventricular fibrillation during the vulnerable period of the cardiac cycle. This shock strength (the upper limit of vulnerability) closely correlates with the defibrillation threshold and supports the "upper limit of vulnerability" hypothesis of defibrillation. It is not known whether an upper limit of vulnerability exists in humans or whether this limit correlates with the defibrillation threshold. Methods and Results. In 13 patients undergoing implantable cardioverter-defibrillator implantation, the shock strengths associated with a 50% probability of reaching the upper limit of vulnerability (ULV50) and a 50% probability of reaching the defibrillation threshold (DFT50) were determined by the up-down algorithm. The ULV50 was determined only for the mid-upslope of the positive T waves and for the mid-downslope of the negative T waves. No major complications occurred during surgery. An upper limit of vulnerability was demonstrated in each patient. The ULV50 was 300±138 V or 6.8±5.8 J, which was significantly lower than the DFT50 of 347±167 V (p=0.038) or 9.1+7.3 J (p=0.013). The correlation between the ULV50 and the DFT50 was significant (r=0.90, p<0.001 for voltage; r=0.93, p<0.001 for energy). Conclusions. An upper limit of vulnerability is present in humans. There is a significant correlation between the ULV50 and the DFT50, and the ULV50 is significantly lower than the DFT50.

Original languageEnglish (US)
Pages (from-to)186-192
Number of pages7
JournalCirculation
Volume88
Issue number1
DOIs
StatePublished - Jul 1993
Externally publishedYes

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Keywords

  • Electrophysiology
  • Implantable cardioverter-defibrillator
  • Sudden cardiac death
  • Ventricular fibrillation
  • Ventricular tachycardia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Chen, P. S., Feld, G. K., Kriett, J. M., Mower, M. M., Tarazi, R. Y., Fleck, R. P., Swerdlow, C. D., Gang, E. S., & Kass, R. M. (1993). Relation between upper limit of vulnerability and defibrillation threshold in humans. Circulation, 88(1), 186-192. https://doi.org/10.1161/01.CIR.88.1.186