@Article{RSM:Jol2010,
  author =       "M. Jolley and J. Stinstra and J. Tate and S. Pieper and
                 R.S. MacLeod and L. Chu and P. Wang and J.K. Triedman",
  title =        "Finite element modeling of subcutaneous implantable
                 defibrillator electrodes in an adult torso.",
  journal =      j-HR,
  year =         2010,
  month =        "May",
  volume =       7,
  number =       5,
  pages =        "692--698",
  robnote =      "BACKGROUND: Total subcutaneous implantable subcutaneous
                 defibrillators are in development, but optimal electrode
                 configurations are not known. OBJECTIVE: We used
                 image-based finite element models (FEM) to predict the
                 myocardial electric field generated during defibrillation
                 shocks (pseudo-DFT) in a wide variety of reported and
                 innovative subcutaneous electrode positions to determine
                 factors affecting optimal lead positions for subcutaneous
                 implantable cardioverter-defibrillators (S-ICD). METHODS:
                 An image-based FEM of an adult man was used to predict
                 pseudo-DFTs across a wide range of technically feasible
                 S-ICD electrode placements. Generator location, lead
                 location, length, geometry and orientation, and spatial
                 relation of electrodes to ventricular mass were
                 systematically varied. Best electrode configurations were
                 determined, and spatial factors contributing to low
                 pseudo-DFTs were identified using regression and general
                 linear models. RESULTS: A total of 122
                 single-electrode/array configurations and 28
                 dual-electrode configurations were simulated. Pseudo-DFTs
                 for single-electrode orientations ranged from 0.60 to 16.0
                 (mean 2.65 +/- 2.48) times that predicted for the base
                 case, an anterior-posterior configuration recently tested
                 clinically. A total of 32 of 150 tested configurations
                 (21\%) had pseudo-DFT ratios </=1, indicating the
                 possibility of multiple novel, efficient, and clinically
                 relevant orientations. Favorable alignment of
                 lead-generator vector with ventricular myocardium and
                 increased lead length were the most important factors
                 correlated with pseudo-DFT, accounting for 70\% of the
                 predicted variation (R(2) = 0.70, each factor P < .05) in
                 a combined general linear model in which parameter
                 estimates were calculated for each factor. CONCLUSION:
                 Further exploration of novel and efficient electrode
                 configurations may be of value in the development of the
                 S-ICD technologies and implant procedure. FEM modeling
                 suggests that the choice of configurations that maximize
                 shock vector alignment with the center of myocardial mass
                 and use of longer leads is more likely to result in lower
                 DFT.",
  pmcid =        "PMC3103844",
  bibdate =      "Tue May 25 06:09:13 2010",
}