Defibrillation with Low Voltage using a Left Ventricular Catheter and Four Cutaneous Patch Electrodes in Dogs

Academic Article


  • The purpose of this study was to determine a lower limit of defibrillation thresholds (DFTs) that could be used to evaluate nonthoracolomy lead configurations for implabtable defibrillators. A lead configuration that consisted of a left ventricular catheter and four cimcumferential cutaneous patches was tested because it was hypothesized to create a relatively uniform electric field for defibrillation. In eight anesthetized dogs, three 8F defibrillaling catheters with 6 cm platinum clad titanium tips were inserted into the right ventricle (R), right ventricular outflow tract (O), and left ventricle (1). Four cutaneous patch electrodes (4P), each with a surface area of 42 cm2, were placed on the left lateral, right lateral, anterior and posterior thorax. DFTs for ten lead configurations, consisting of different combinations of these electrodes, were evaluated. DFTs were determined by using a modified Purdue technique and applying a single capacitor biphasic shock with both phases 6 ms in duration after 15 sec of electrically induced fibrillation The L−→4P+ configuration produced a lower DFT than R−→4P+ (3.2 ± 1.6 J vs 8.0 ± 4.2 J, P < 0.001) with reduced current (2.6 ± 0.7 A vs 4.1 ± 1.2 A, P < 0.001). Lowering the impedance by a mean of 40%, configurations that used four patches produced lower DFTs than those that used a single left lateral patch. The use of an O catheter produced lower DFTs only when used in conjunction with an R catheter. Of the ten configurations tested, L−→4P+ produced the lowest DFT for two possible reasons; (1) it produced a more uniform distribution of current density throughout the ventricular mass, and (2) the large surface area of the cutaneous electrodes decreased the impedance. While this configuration may not be useful clinically, it approximates a minimum DFT that can be used to judge the efficacy of more practical lead configurations. Copyright © 1991, Wiley Blackwell. All rights reserved
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  • Start Page

  • 443
  • End Page

  • 451
  • Volume

  • 14
  • Issue

  • 3