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Method and apparatus for termination of ventricular tachycardia and ventricular fibrillation

  • US 5,224,475 A
  • Filed: 11/20/1991
  • Issued: 07/06/1993
  • Est. Priority Date: 11/20/1991
  • Status: Expired due to Fees
First Claim
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1. An implantable cardioverter or defibrillator, comprising:

  • means for detecting the presence of a tachyarrhythmia;

    pulse generator means for delivering a cardioversion or defibrillation pulse regimen in response to detection of a tachyarrhythmia by said detection means;

    electrode means for delivering said cardioversion or defibrillation pulse regimen to a heart, said electrode means comprising a plurality of electrodes, said electrodes defining a plurality of pulse pathways between ones of said electrodes;

    means for selecting which of said defibrillation pathways are to be employed during the delivery of said defibrillation or cardioversion pulse regimen;

    means for measuring the impedance of each of said selected pathways during delivery of said cardioversion or defibrillation regimen;

    means for defining a reference impedance for each of said selected pathways;

    means for comparing each said measured impedance associated with delivery of said cardioversion or defibrillation pulse regimen with a said reference impedance for each said selected pathway to determine whether said measured impedance differs by more than a predetermined amount from said reference impedance;

    means for determining whether said cardioversion or defibrillation pulse regimen was effective to terminate said detected tachyarrhythmia; and

    means responsive to said comparing means and to said determining means for rendering any said pathway for which said measured impedance differs by more than said previous predetermined amount from said reference impedance unavailable for future cardioversion or defibrillation regimens, provided that said cardioversion or defibrillation pulse regimen is determined to be ineffective in terminating said detected tachyarrhythmia.

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