Double-pulse defibrillation using pulse separation based on the fibrillation cycle length.

Abstract

INTRODUCTION:

We investigated a method of defibrillation in which two shocks were delivered to the same electrodes with a separation based on the cycle length of the fibrillation event (FCL).

METHODS AND RESULTS:

In pentobarbital anesthetized dogs, a computerized system determined the FCL from the fibrillation event, computed the desired double-pulse (DP) shock separation, and immediately delivered the DP shocks. In group 1, energy for 50% success at defibrillation (E50) was measured using separations from 55% to 95% of the FCL and remeasured after administration of flecainide, clofilium, or vehicle to change the FCL. Both drugs increased FCL by approximately 25%. Plots of E50 versus %FCL aligned before and after drug showed that the optimum pulse separation followed the FCL. In group 2, E50s were measured for 55% to 185% FCL separations in clofilium or vehicle-treated animals. The optimum DP E50 was at 85% FCL and was not significantly different from the single-shock E50. In group 3, no differences were found when comparing the probability of success versus total energy relationships for single and optimum DP shocks. Group 4 compared E50s for single and DP shocks using a single-catheter configuration and three-electrode configurations (catheter-subdermal patch). E50s for single and DP shocks were equal using the single-catheter configuration but DP shocks required approximately 20% more energy in the three-electrode configurations.

CONCLUSION:

In single-pathway lead configurations, two shocks with 85% FCL separation can be reliably combined to defibrillate using the same total energy as a larger single shock. Since the energy is unchanged but the total duration is doubled, DP shock currents are reduced by 20% to 30%.

• Authors: R J Sweeney, R M Gill, P R Reid
• Journal: Journal of cardiovascular electrophysiology (J Cardiovasc Electrophysiol) Vol. 5 Issue 9 Pg. 761-70 (Sep 1994) ISSN: 1045-3873 [Print] United States
• PMID: 7827715 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anti-Arrhythmia Agents

Topics

• Animals
• Anti-Arrhythmia Agents (pharmacology)
• Defibrillators, Implantable
• Dogs
• Electric Countershock (methods)
• Electrocardiography
• Female
• Male
• Ventricular Fibrillation (physiopathology, therapy)