A comparison of defibrillation efficacy between different impedance compensation techniques in high impedance porcine model

Yongqin Li, Giuseppe Ristagno, Tao Yu, Joe Bisera, Max Harry Weil, Wanchun Tang

Research output: Contribution to journalArticlepeer-review


Aim of study: Impedance compensation methods differ markedly among manufacturers and can play an important role in defibrillation success. In this study we compared the efficacy of two different commercial defibrillators based on defibrillation success in a high impedance porcine model of cardiac arrest. The first defibrillator (A) compensates high impedance by controlling current with fixed shock duration, while the second defibrillator (B) by prolonging the shock duration. Methods: In 10 domestic male pigs weighing between 17 and 28 kg, ventricular fibrillation was electrically induced and untreated for 15 s. Animals were randomized to receive defibrillations with either defibrillator A or defibrillator B, at maximum energy settings of which were 200 J for the defibrillator A and 360 J for the defibrillator B. A grouped up-down defibrillation threshold testing protocol was used to compare the success rate between the two defibrillators. A variable resistance, ranging from 80 to 200 ohm was placed in series with the defibrillation pads. After a recovery interval of 5 min, the sequence was repeated for a total of 60 test shocks for each animal. Results: The measured total pathway impedance was in a range of 108-278 ohm. The combined success rate was 49.5% for the two defibrillators in a total of 600 testing shocks. The success rate was significantly higher when the defibrillator A was employed in comparison with defibrillator B (63% vs. 36%, p = 0.0001). Conclusion: For transthoracic impedances greater than average, the current-based compensation technique was more effective than the duration-based compensation technique.

Original languageEnglish
Pages (from-to)1312-1317
Number of pages6
Issue number11
Publication statusPublished - Nov 2009


  • Cardiac arrest
  • Defibrillation efficacy
  • High impedance
  • Impedance compensation
  • Ventricular fibrillation

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Emergency
  • Emergency Medicine


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