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US 6,298,266 B1Granted
Methods and apparatus for treating fibrillation and creating defibrillation waveforms
AssigneeIntermedics, Inc.
InventorsLeo Rubin, Christopher A. Bonnerup, Edward A. Schroeppel
Life of this patent
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Abstract
Methods and apparatus for treating fibrillation utilize biphasic waveforms. A cardiac stimulator includes a defibrillation circuit that uses a pulse width modulated capacitive discharge to generate various biphasic waveforms, one or more of which may be delivered to the heart to treat the fibrillation.
Claims20
A defibrillation waveform generator comprising:
- an arrhythmia detector adapted to be coupled to a heart, the arrhythmia detector delivering a detection signal in response to detecting fibrillation in the heart;
- a capacitor:
- a charging circuit coupled to the capacitor, the charging circuit charging the capacitor to a given voltage;
- a controller operably coupled to the arrhythmia detector to receive the detection signal, the controller delivering a first control signal, a second control signal, and a third control signal in response to receiving the detection signal;
- a voltage-to-frequency convertor coupled to the controller to receive the first control signal, the voltage-to-frequency convertor delivering a frequency signal having a frequency correlative to the first control signal;
- a pulse width modulator coupled to the controller to receive the second control signal and coupled to the voltage-to-frequency convertor to receive the frequency signal, the pulse width modulator delivering a pulse width modulated signal having a frequency correlative to the frequency signal and having a duty cycle correlative to the second control signal;
- and
- a switching circuit adapted to be coupled between the capacitor and the heart, the switching circuit being coupled to the controller to receive the third control signal and to the pulse width modulator to receive the pulse width modulated signal, the switching circuit controllably discharging the capacitor across the heart to deliver a defibrillation waveform in response to the third control signal and the pulse width modulated signal.
5 more elements
A defibrillation waveform generator comprising:
- an arrhythmia detector adapted to be coupled to a heart, the arrhythmia detector delivering a detection signal in response to detecting fibrillation in the heart;
- a first capacitor;
- a charging circuit coupled to the first capacitor and to a second capacitor, the charging circuit charging the first capacitor and the second capacitor to a respective given voltage;
- a controller operably coupled to the arrhythmia detector to receive the detection signal, the controller delivering a first control signal, a second control signal, and a third control signal in response to receiving the detection signal;
- a voltage-to-frequency convertor coupled to the controller to receive the first control signal, the voltage-to-frequency convertor delivering a frequency signal having a frequency correlative to the first control signal;
- a pulse width modulator coupled to the controller to receive the second control signal and coupled to the voltage-to-frequency convertor to receive the frequency signal, the pulse width modulator delivering a pulse width modulated signal having a frequency correlative to the frequency signal and having a duty cycle correlative to the second control signal;
- and
- a switching circuit adapted to be coupled between the first and second capacitors and the heart, the switching circuit being coupled to the controller to receive the third control signal and to the pulse width modulator to receive the pulse width modulated signal, the switching circuit controllably discharging the first capacitor across the heart to deliver a positive phase defibrillation waveform in response to the third control signal and the pulse width modulated signal, and the switching circuit controllably discharging the second capacitor across the heart to deliver a negative phase defibrillation waveform in response to the third control signal and the pulse width modulated signal.
5 more elements
A cardiac stimulator for treating fibrillations comprising:
- an implantable case containing:
- an atrial sensing circuit adapted to deliver an atrial signal correlative to a condition of an atrium of a heart;
- a ventricular sensing circuit adapted to deliver a ventricular signal correlative to a condition of a ventricle of the heart;
- an inductor-less pulse generator adapted to deliver pulse width modulated electrical stimulation to the ventricle;
- and
- a control circuit coupled to the ventricular sensing circuit to receive the ventricular signal, the control circuit classifying a ventricular tachyarrhythmia as a fibrillation and directing the pulse generator to deliver pulse width modulated electrical stimulation to the ventricle in response to the classifying a ventricular tachyarrhythmia as a fibrillation.
3 more elements
A cardiac stimulator comprising:
- means for determining whether a fibrillation exists in a ventricle;
- means for charging at least one capacitor;
- and
- means for discharging the at least one capacitor in a pulse width modulated manner to the ventricle to create a defibrillation waveform for treating the fibrillation.
1 more element
A method of treating fibrillation comprising the acts of:
- (a) determining whether a fibrillation exists in a ventricle;
- (b) charging at least one capacitor;
- and
- (c) electrically stimulating the ventricle with a pulse width modulated waveform to treat the fibrillation by discharging the at least one capacitor in a pulse width modulated manner.
1 more element
A defibrillator comprising:
- first and second outputs, adapted for being coupled to a heart;
- a capacitor for storing defibrillation energy, the capacitor having first and second terminals;
- a charging circuit, coupled to the capacitor;
- a pulse-width-modulated (PWM) switching circuit coupling the capacitor to the first and second outputs for delivering a PWM defibrillation waveform to the heart, the PWM defibrillation waveform for delivery to the heart including a switching frequency that is greater than about 5 kilohertz.
1 more element
A defibrillator comprising:
- first and second outputs, adapted for being coupled to a heart;
- a first capacitor for storing defibrillation energy at a first polarity;
- a second capacitor for storing defibrillation energy at a second polarity that is opposite the first polarity;
- a charging circuit, coupled to at least one of the first and second capacitors;
- a pulse-width-modulated (PWM) switching circuit coupling the first and second capacitors to the first and second outputs for delivering a PWM defibrillation waveform to the heart, the PWM defibrillation waveform for delivery to the heart including a switching frequency that is greater than about 5 kilohertz.
2 more elements
A method including:
- detecting an arrhythmia in a heart;
- charging a defibrillation energy storage capacitor;
- and
- coupling the storage capacitor to the heart, using a switching circuit at a switching frequency that exceeds about 5 kilohertz, to deliver defibrillation energy to the heart;
- and
- modulating a switching frequency of the switching circuit to shape a waveform of the defibrillation energy being delivered to the heart.
3 more elements
A method including:
- detecting an arrhythmia in a heart;
- charging first and second defibrillation energy storage capacitors;
- and
- coupling the first storage capacitor to the heart, using a switching circuit at a switching frequency that exceeds about 5 kilohertz, to deliver defibrillation energy to the heart at a first polarity;
- coupling the second storage capacitor to the heart, using the switching circuit at a switching frequency that exceeds about 5 kilohertz, to deliver defibrillation energy to the heart at a second polarity;
- modulating a switching frequency of the switching circuit to shape a waveform of the defibrillation energy being delivered to the heart.
3 more elements
Dependencies are inferred from the claim text.