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Prolongation of repolarization time by electric field stimulation with monophasic and biphasic shocks in open-chest dogs.

Publication ,  Journal Article
Zhou, XH; Knisley, SB; Wolf, PD; Rollins, DL; Smith, WM; Ideker, RE
Published in: Circulation research
June 1991

Recent studies suggest that 1) electrically induced fibrillation and defibrillation involve prolongation of refractoriness by the shock in addition to stimulation and 2) biphasic waveforms are more efficient for defibrillation than are comparable monophasic waveforms. The purpose of this study was to compare prolongation of action potential duration at 50% repolarization by monophasic and biphasic shocks during paced rhythm. A floating glass microelectrode was used to record intracellularly from the anterior right ventricular epicardium in seven open-chest dogs. After 10 S1 beats paced at an interval of 350 msec, 5-msec and 2.5-msec monophasic shocks and biphasic shocks, with each phase of 2.5 msec, were given via mesh electrodes on either side of the microelectrode. The shock strength was adjusted so that the shock field, measured from eight extracellular electrodes encircling the microelectrode, was about 5 V/cm. Monophasic and biphasic S2 shocks were given starting with an S1-S2 interval of 120 msec, which was increased in 5-msec steps until an action potential was produced by the S2 shock. Both monophasic and biphasic 5 V/cm shock fields caused significant prolongation of action potential duration. The prolongation of action potential duration increased as the S1-S2 interval increased. This prolongation occurred at shorter S1-S2 intervals for 5-msec monophasic shocks than for biphasic shocks.

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Published In

Circulation research

DOI

EISSN

1524-4571

ISSN

0009-7330

Publication Date

June 1991

Volume

68

Issue

6

Start / End Page

1761 / 1767

Related Subject Headings

  • Ventricular Fibrillation
  • Reaction Time
  • Heart
  • Electrophysiology
  • Electric Countershock
  • Dogs
  • Cardiovascular System & Hematology
  • Cardiac Pacing, Artificial
  • Animals
  • Action Potentials
 

Citation

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Zhou, X. H., Knisley, S. B., Wolf, P. D., Rollins, D. L., Smith, W. M., & Ideker, R. E. (1991). Prolongation of repolarization time by electric field stimulation with monophasic and biphasic shocks in open-chest dogs. Circulation Research, 68(6), 1761–1767. https://doi.org/10.1161/01.res.68.6.1761
Zhou, X. H., S. B. Knisley, P. D. Wolf, D. L. Rollins, W. M. Smith, and R. E. Ideker. “Prolongation of repolarization time by electric field stimulation with monophasic and biphasic shocks in open-chest dogs.Circulation Research 68, no. 6 (June 1991): 1761–67. https://doi.org/10.1161/01.res.68.6.1761.
Zhou XH, Knisley SB, Wolf PD, Rollins DL, Smith WM, Ideker RE. Prolongation of repolarization time by electric field stimulation with monophasic and biphasic shocks in open-chest dogs. Circulation research. 1991 Jun;68(6):1761–7.
Zhou, X. H., et al. “Prolongation of repolarization time by electric field stimulation with monophasic and biphasic shocks in open-chest dogs.Circulation Research, vol. 68, no. 6, June 1991, pp. 1761–67. Epmc, doi:10.1161/01.res.68.6.1761.
Zhou XH, Knisley SB, Wolf PD, Rollins DL, Smith WM, Ideker RE. Prolongation of repolarization time by electric field stimulation with monophasic and biphasic shocks in open-chest dogs. Circulation research. 1991 Jun;68(6):1761–1767.

Published In

Circulation research

DOI

EISSN

1524-4571

ISSN

0009-7330

Publication Date

June 1991

Volume

68

Issue

6

Start / End Page

1761 / 1767

Related Subject Headings

  • Ventricular Fibrillation
  • Reaction Time
  • Heart
  • Electrophysiology
  • Electric Countershock
  • Dogs
  • Cardiovascular System & Hematology
  • Cardiac Pacing, Artificial
  • Animals
  • Action Potentials