Method and apparatus for termination of ventricular tachycardia and ventricular fibrillation
First Claim
1. An implantable cardioverter or defibrillator, comprising:
- means for detecting the presence of a tachyarrhythmia;
pulse generator means for delivering cardioversion or defibrillation pulses in response to detection of tachyarrhythmia by said detection means;
electrode means for delivering said cardioversion or defibrillation pulses to a heart, said electrode means comprising at least three electrodes, defining at least two pulse pathways;
means for measuring the impedance of said pathways, between said electrodes during delivery of said cardioversion or defibrillation pulses; and
means for setting the relative amplitudes of subsequent cardioversion or defibrillation pulses, delivered along said pathways, as a function of the impedances measured by said measuring means, in order to provide a more uniform current density, during delivery of pulses along said pathways.
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Abstract
An implantable defibrillator provided with a plurality of defibrillation electrodes, which may be reconfigured to define a plurality of defibrillation pathways. The device is capable of measuring the impedance along a selected defibrillation pathway, during delivery of an impedance pulse, and monitoring the success or failure of the pulse to accomplish defibrillation or cardioversion. In response to a detected failure to accomplish cardioversion in conjunction with a measured change of impedance of greater than a predetermined amount, a new defibrillation pathway is selected, which may employ some or all of the electrodes employed to define the original impedance pathway. The device also includes apparatus for varying the relative amplitude of defibrillation pulses applied to individual electrodes used in sequential or simultaneous, multiple electrode pulse regimens, in order to equalize current distribution, in response to measured pathway impedances.
130 Citations
21 Claims
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1. An implantable cardioverter or defibrillator, comprising:
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means for detecting the presence of a tachyarrhythmia; pulse generator means for delivering cardioversion or defibrillation pulses in response to detection of tachyarrhythmia by said detection means; electrode means for delivering said cardioversion or defibrillation pulses to a heart, said electrode means comprising at least three electrodes, defining at least two pulse pathways; means for measuring the impedance of said pathways, between said electrodes during delivery of said cardioversion or defibrillation pulses; and means for setting the relative amplitudes of subsequent cardioversion or defibrillation pulses, delivered along said pathways, as a function of the impedances measured by said measuring means, in order to provide a more uniform current density, during delivery of pulses along said pathways. - View Dependent Claims (2, 3, 4, 5)
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6. A method for cardioverting or defibrillating a heart, comprising:
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locating a set of three or more electrodes relative to said heart to define at least two pulse pathways; determining the relative impedance along said at least two pulse pathways; deriving the relative electrical energy levels of pulses to be delivered for each of said pathways, as a function of said determined impedances; detecting a tachyarrhythmia; and in response to detecting said tachyarrhythmia, delivering pulses along said at least two pathways at said derived energy levels. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. Apparatus for cardioverting or defibrillating a heart, comprising:
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three or more electrodes located relative to said heart to define at least two pulse pathways; means for determining the relative impedances along said at least two pulse pathways; means for deriving the relative electrical energy levels of pulses to be delivered for each of said pathways, as a function of said determined impedances; means for detecting a tachyarrhythmia; and means responsive to detecting said tachyarrhythmia, for delivering pulses along said at least two pathways at said derived energy levels. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification