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A Rat Model of Ventricular Fibrillation and Resuscitation by Conventional Closed-chest Technique
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Effects of combined sildenafil-nitric oxide donor on defibrillation efficacy

Krekwit Shinlapawittayatorn1, Siriporn Chattipakorn, Rattapong Sungnoon

  • 1Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.

Journal of the Medical Association of Thailand = Chotmaihet Thangphaet
|November 29, 2007
PubMed
Abstract

Insights

High doses of sildenafil combined with nitroglycerin (NTG) significantly increase the defibrillation threshold (DFT). This effect on DFT is primarily due to sildenafil, not NTG.

Area of Science:

  • Cardiology
  • Pharmacology
  • Critical Care Medicine

Background:

  • Sildenafil citrate at supra-therapeutic concentrations can reduce defibrillation efficacy.
  • The impact of combining therapeutic sildenafil levels with nitroglycerin (NTG) on defibrillation is unknown.

Purpose of the Study:

  • To determine if therapeutic sildenafil levels, when combined with NTG, elevate the defibrillation threshold (DFT).

Main Methods:

  • Twenty-four pigs were randomized into four groups.
  • Sildenafil (50mg or 100mg) or saline was infused, followed by NTG administration.
  • Defibrillation threshold (DFT) was measured before and after NTG infusion.

Main Results:

  • Therapeutic sildenafil with NTG did not alter DFT.
  • Supra-therapeutic sildenafil with NTG significantly increased DFT (p < 0.004).
  • Saline did not affect DFT, alone or with NTG.

Conclusions:

  • A supra-therapeutic dose of sildenafil in combination with NTG significantly elevates the DFT.
  • The increase in DFT appears to be driven by sildenafil, not NTG.

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