Effect of ventricular shock strength on cardiac hemodynamics

Takashi Tokano, David Bach, Jason Chang, James Davis, Joseph J. Souza, Adam Zivin, Bradley P. Knight, Rajiva Goyal, K. Ching Man, Fred Morady, S. Adam Strickberger*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

127 Scopus citations

Abstract

Introduction: The effect of implantable defibrillator shocks on cardiac hemodynamics is poorly understood. The purpose of this study was to test the hypothesis that ventricular defibrillator shocks adversely effect cardiac hemodynamics. Methods and Results: The cardiac index was determined by calculating the mitral valve inflow with transesophogeal Doppler during nonthoracotomy defibrillator implantation in 17 patients. The cardiac index was determined before, and immediately, 1 minute, 2 minutes, and 4 minutes after shocks were delivered during defibrillation energy requirement testing with 27- to 34-, 15-, 10-, 5-, 3-, or 1-J shocks. The cardiac index was also measured at the same time points after 27- to 34-, and 1-J shocks delivered during the baseline rhythm. The cardiac index decreased from 2.30±0.40 L/min per m2 before a 27- to 34-J shock during defibrillation energy requirement testing to 2.14 ± 0.45 L/min per m2 immediately afterwards (P = 0.001). This effect persisted for >4 minutes. An adverse hemodynamic effect of similar magnitude occurred after 15 J (P = 0.003) and 10-J shocks (P = 0.01), but dissipated after 4 minutes and within 2 minutes, respectively. There was a significant correlation between shock strength and the percent change in cardiac index (r = 0.3, P = 0.03). The cardiac index decreased 14% after a 27- to 34-J shock during the baseline rhythm (P < 0.0001). This effect persisted for <4 minutes. A 1-J shock during the baseline rhythm did not effect the cardiac index. Conclusion: Defibrillator shocks > 9 J delivered during the baseline rhythm or during defibrillation energy requirement testing result in a 10% to 15% reduction in cardiac index, whereas smaller energy shocks do not affect cardiac hemodynamics. The duration and extent of the adverse effect are proportional to the shock strength. Shock strength, and not ventricular fibrillation, appears to be most responsible for this effect. Therefore, the detrimental hemodynamic effects of high-energy shocks may be avoided when low-energy defibrillation is used.

Original languageEnglish (US)
Pages (from-to)791-797
Number of pages7
JournalJournal of cardiovascular electrophysiology
Volume9
Issue number8
DOIs
StatePublished - 1998

Keywords

  • Cardiac index
  • Cardiac output
  • Defibrillation threshold
  • Implantable cardioverter defibrillator
  • Stunning

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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