Effect of pulse separation between two sequential biphasic shocks given over different lead configurations on ventricular defibrillation efficacy

Eric Johnson, Clif A. Alferness, Patrick D. Wolf, William M. Smith, Raymond E. Ideker

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Background. Two sequential biphasic shocks delivered over separate lead configurations markedly improve defibrillation efficacy compared with a single shock alone. We investigated the effect of varying the intershock interval between sequential biphasic shocks on defibrillation. Methods and Results. Defibrillation thresholds (DFTs) were obtained in six dogs for shock separations ranging from 0.2 to 125 msec. The first shock was given from a catheter electrode in the right ventricular apex to a patch on the left lateral thorax; the second was from a small patch on the left ventricular apex to a catheter electrode in the right ventricular outflow tract. When the interval between shocks was < 10 msec or ≥75 and ≤125 msec, the mean DFTs were less than that previously found for the first shock by itself (4.2 versus 7.4 J, p=0.002). At a separation of 50 msec, however, there was a marked rise in the DFT to 27 J. The mean DFT for the second shock at a delay of 50 msec was not different from the mean DFT previously found for the second shock by itself (7.2 versus 7.0 J). These results were confirmed in another six dogs using defibrillation probability-of-success curves. In 12 other dogs, probability-of-success curves were generated for delays between shocks as a percentage of the activation interval during ventricular fibrillation. Minimum defibrillation energy requirements were at two separations, 0.2 msec and 90% of the activation interval. Conclusions. The optimal intershock interval between two sequential biphasic shocks is either ≤10 msec or ≥75 and ≤125 msec. The marked rise in the DFT at a shock separation of 50 msec, requiring more energy than that for the first shock alone, suggests that the second shock at this time delay is likely to reinduce fibrillation after it is halted by the first shock until the second shock is strong enough to defibrillate independently of the first shock.

Original languageEnglish (US)
Pages (from-to)2267-2274
Number of pages8
JournalCirculation
Volume85
Issue number6
DOIs
StatePublished - Jan 1 1992

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Shock
Lead
Dogs
Electrodes
Catheters
Ventricular Fibrillation
Thorax

All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Effect of pulse separation between two sequential biphasic shocks given over different lead configurations on ventricular defibrillation efficacy. / Johnson, Eric; Alferness, Clif A.; Wolf, Patrick D.; Smith, William M.; Ideker, Raymond E.

In: Circulation, Vol. 85, No. 6, 01.01.1992, p. 2267-2274.

Research output: Contribution to journalArticle

Johnson, Eric ; Alferness, Clif A. ; Wolf, Patrick D. ; Smith, William M. ; Ideker, Raymond E. / Effect of pulse separation between two sequential biphasic shocks given over different lead configurations on ventricular defibrillation efficacy. In: Circulation. 1992 ; Vol. 85, No. 6. pp. 2267-2274.
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abstract = "Background. Two sequential biphasic shocks delivered over separate lead configurations markedly improve defibrillation efficacy compared with a single shock alone. We investigated the effect of varying the intershock interval between sequential biphasic shocks on defibrillation. Methods and Results. Defibrillation thresholds (DFTs) were obtained in six dogs for shock separations ranging from 0.2 to 125 msec. The first shock was given from a catheter electrode in the right ventricular apex to a patch on the left lateral thorax; the second was from a small patch on the left ventricular apex to a catheter electrode in the right ventricular outflow tract. When the interval between shocks was < 10 msec or ≥75 and ≤125 msec, the mean DFTs were less than that previously found for the first shock by itself (4.2 versus 7.4 J, p=0.002). At a separation of 50 msec, however, there was a marked rise in the DFT to 27 J. The mean DFT for the second shock at a delay of 50 msec was not different from the mean DFT previously found for the second shock by itself (7.2 versus 7.0 J). These results were confirmed in another six dogs using defibrillation probability-of-success curves. In 12 other dogs, probability-of-success curves were generated for delays between shocks as a percentage of the activation interval during ventricular fibrillation. Minimum defibrillation energy requirements were at two separations, 0.2 msec and 90{\%} of the activation interval. Conclusions. The optimal intershock interval between two sequential biphasic shocks is either ≤10 msec or ≥75 and ≤125 msec. The marked rise in the DFT at a shock separation of 50 msec, requiring more energy than that for the first shock alone, suggests that the second shock at this time delay is likely to reinduce fibrillation after it is halted by the first shock until the second shock is strong enough to defibrillate independently of the first shock.",
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AU - Ideker, Raymond E.

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N2 - Background. Two sequential biphasic shocks delivered over separate lead configurations markedly improve defibrillation efficacy compared with a single shock alone. We investigated the effect of varying the intershock interval between sequential biphasic shocks on defibrillation. Methods and Results. Defibrillation thresholds (DFTs) were obtained in six dogs for shock separations ranging from 0.2 to 125 msec. The first shock was given from a catheter electrode in the right ventricular apex to a patch on the left lateral thorax; the second was from a small patch on the left ventricular apex to a catheter electrode in the right ventricular outflow tract. When the interval between shocks was < 10 msec or ≥75 and ≤125 msec, the mean DFTs were less than that previously found for the first shock by itself (4.2 versus 7.4 J, p=0.002). At a separation of 50 msec, however, there was a marked rise in the DFT to 27 J. The mean DFT for the second shock at a delay of 50 msec was not different from the mean DFT previously found for the second shock by itself (7.2 versus 7.0 J). These results were confirmed in another six dogs using defibrillation probability-of-success curves. In 12 other dogs, probability-of-success curves were generated for delays between shocks as a percentage of the activation interval during ventricular fibrillation. Minimum defibrillation energy requirements were at two separations, 0.2 msec and 90% of the activation interval. Conclusions. The optimal intershock interval between two sequential biphasic shocks is either ≤10 msec or ≥75 and ≤125 msec. The marked rise in the DFT at a shock separation of 50 msec, requiring more energy than that for the first shock alone, suggests that the second shock at this time delay is likely to reinduce fibrillation after it is halted by the first shock until the second shock is strong enough to defibrillate independently of the first shock.

AB - Background. Two sequential biphasic shocks delivered over separate lead configurations markedly improve defibrillation efficacy compared with a single shock alone. We investigated the effect of varying the intershock interval between sequential biphasic shocks on defibrillation. Methods and Results. Defibrillation thresholds (DFTs) were obtained in six dogs for shock separations ranging from 0.2 to 125 msec. The first shock was given from a catheter electrode in the right ventricular apex to a patch on the left lateral thorax; the second was from a small patch on the left ventricular apex to a catheter electrode in the right ventricular outflow tract. When the interval between shocks was < 10 msec or ≥75 and ≤125 msec, the mean DFTs were less than that previously found for the first shock by itself (4.2 versus 7.4 J, p=0.002). At a separation of 50 msec, however, there was a marked rise in the DFT to 27 J. The mean DFT for the second shock at a delay of 50 msec was not different from the mean DFT previously found for the second shock by itself (7.2 versus 7.0 J). These results were confirmed in another six dogs using defibrillation probability-of-success curves. In 12 other dogs, probability-of-success curves were generated for delays between shocks as a percentage of the activation interval during ventricular fibrillation. Minimum defibrillation energy requirements were at two separations, 0.2 msec and 90% of the activation interval. Conclusions. The optimal intershock interval between two sequential biphasic shocks is either ≤10 msec or ≥75 and ≤125 msec. The marked rise in the DFT at a shock separation of 50 msec, requiring more energy than that for the first shock alone, suggests that the second shock at this time delay is likely to reinduce fibrillation after it is halted by the first shock until the second shock is strong enough to defibrillate independently of the first shock.

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