Method and apparatus for applying asymmetric biphasic truncated exponential countershocks
First Claim
1. A method for applying electrotherapy to the heart by way of conductive leads electrically connected to electrodes associated with the heart, said leads and electrodes being for conducting pulses of electrical current to the heart, comprising the steps of:
- charging a capacitor to a voltage corresponding to a first start amplitude;
discharging said capacitor through said leads to a voltage corresponding to a first end amplitude;
to thereby apply a first truncated exponential waveform of a first polarity to said leads, said first truncated exponential waveform having said first start amplitude and said first end amplitude;
reversing polarity of connection of said capacitor to said leads; and
discharging said capacitor to a voltage corresponding to a second end amplitude to thereby apply a second truncated exponential waveform of a second polarity opposite that of said first polarity to said leads;
said second truncated exponential waveform having second start amplitude and said second end amplitude;
said second start amplitude being lower than said first start amplitude.
2 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for applying an asymmetric biphasic exponential waveform countershock to the heart useful in an implantable cardioverter or defibrillator, wherein the second phase has a start amplitude of substantially one half that of the first phase, and wherein the polarity of a capacitor discharging through a current path including the heart is reversed. A voltage reversing circuit may include a voltage shifter which shifts voltage associated with switching elements in the circuit to reduce voltage stresses in the switching elements.
-
Citations
18 Claims
-
1. A method for applying electrotherapy to the heart by way of conductive leads electrically connected to electrodes associated with the heart, said leads and electrodes being for conducting pulses of electrical current to the heart, comprising the steps of:
-
charging a capacitor to a voltage corresponding to a first start amplitude; discharging said capacitor through said leads to a voltage corresponding to a first end amplitude;
to thereby apply a first truncated exponential waveform of a first polarity to said leads, said first truncated exponential waveform having said first start amplitude and said first end amplitude;reversing polarity of connection of said capacitor to said leads; and discharging said capacitor to a voltage corresponding to a second end amplitude to thereby apply a second truncated exponential waveform of a second polarity opposite that of said first polarity to said leads;
said second truncated exponential waveform having second start amplitude and said second end amplitude;said second start amplitude being lower than said first start amplitude. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. An apparatus for administering electrotherapy to a heart comprising:
-
a recognition means responsive to an electrical signal from the heart for determining when the heart is in need of electrotherapy; a capacitive energy storage means for storing electrical energy to be applied to the heart; an energy source means for providing said electrical energy to said energy storage means; conductor means for conducting said stored electrical energy from said energy storage means to the heart; and connection means for connecting said conductor means with a first plurality to administer a first shock, and with a second polarity opposite said first polarity to administer a second shock, after administration of said first shock;
said connection means including;a first switch means for connecting a first terminal of said energy storage means to a first lead to the heart; a second switch means for connecting a second terminal of said energy storage means to a second lead to the heart; a third switch means for connecting said first terminal of said energy storage means to said second lead to the heart; a fourth switch means for connecting said second terminal of said energy storage means to said first lead to the heart; and timing means for closing said first switch means and said second switch means at a first time, for opening said first switch means and said second switch means at a second time after said first time, for closing said third switch means and said fourth switch means at a third time after said second time, and for opening said third switch means and said fourth switch means at a fourth time after said third time. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
-
Specification