Zmd Corporation

Shervin Ayati

Michael L Lopin

An electrotherapy circuit administers to a patient a current waveform. The electrotherapy circuit includes a charge storage device, at least two discharge electrodes connected by electrical circuitry to opposite poles of the charge storage device, a variable impedance connected between the charge storage device and one of the electrodes, a sensor that senses a patient-dependent electrical parameter (such as a patient impedance sensor), and a control circuit. The control circuit is connected to the sensor and the variable impedance and controls the variable impedance during discharge of the charge storage device based on patient-dependent electrical parameter (such as the patient impedance) sensed by the sensor.

Electrotherapy circuit having controlled current discharge based on

The invention provides a method and circuit for forming an electrotherapy current waveform. A charge storage device located externally of a patient's body is charged, and is discharged through the patient's body through at least two discharge electrodes connected by electrical circuitry to opposite poles of the charge storage device. A continuous discharge of the charge storage device through the electrodes is controlled so as to produce at least one phase of a current waveform that includes a ripple. The ripple has a height less than one-third of the height of the peak current of the phase, and the difference between the peak current of the phase and the lowest current of the phase is less than one third of the peak current of the phase. The current waveform has a sensing pulse portion that is integral with the therapeutic discharge portion of the current waveform.

Method and apparatus for producing electrotherapy current waveform with

An electrotherapy circuit administers to a patient a current waveform. The electrotherapy circuit includes a charge storage device, at least two discharge electrodes connected by electrical circuitry to opposite poles of the charge storage device, a sensor that senses a patient-dependent electrical parameter (such as a patient impedance sensor), and a control circuit. The control circuit is connected to the sensor and the charge storage device and controls discharge of the charge storage device through the electrodes. The discharge of the charge storage device includes a current waveform having a sensing pulse portion, with insufficient energy for performing therapy, during which the sensor senses a patient-dependent electrical parameter (such as patient impedance), and a therapeutic discharge portion, with sufficient energy for performing therapy, having an initial discharge current controlled by the control circuit based on the patient-dependent electrical parameter (such as patient impedance) as sensed by the sensor. The sensing pulse portion has a discharge current that is at least about one-third of the initial discharge current of the therapeutic discharge portion.

Electrotherapy circuit for producing therapeutic discharge waveform

An electrotherapy circuit administers to a patient a current waveform. The electrotherapy circuit includes a charge storage device, at least two discharge electrodes connected by electrical circuitry to opposite poles of the charge storage device, a sensor that senses a patient-dependent electrical parameter (such as a patient impedance sensor), and a control circuit. The control circuit is connected to the sensor and the charge storage device and controls discharge of the charge storage device through the electrodes, based on the patient-dependent electrical parameter (such as the patient impedance) as sensed by the sensor. The discharge is controlled in a manner so as to reduce the dependence of peak discharge current on the electrical parameter (such as patient impedance) for a given amount of charge stored by the charge storage device.

Electrotherapy circuit having controlled peak current

An electrotherapy circuit administers to a patient a current waveform. The electrotherapy circuit includes a charge storage device, at least two discharge electrodes connected by electrical circuitry to opposite poles of the charge storage device, and a control circuit. The control circuit is connected to the charge storage device and controls a continuous discharge of the charge storage device through the electrodes so as to produce at least one phase of a current waveform that includes a sawtooth ripple with a height less than about one-quarter of the average height of the phase.

Electrotherapy circuit for producing current waveform with sawtooth

An electrotherapy circuit administers to a patient a current waveform. The electrotherapy circuit includes a charge storage device, at least two discharge electrodes connected by electrical circuitry to opposite poles of the charge storage device, a sensor that senses a patient-dependent electrical parameter (such as a patient impedance sensor), and a control circuit. The control circuit is connected to the sensor and the charge storage device and controls discharge of the charge storage device through the electrodes. The discharge of the charge storage device includes a current waveform having a sensing pulse portion, with insufficient energy for performing therapy, during which the sensor senses a patient-dependent electrical parameter (such as patient impedance), and a therapeutic discharge portion, with sufficient energy for performing therapy, having an initial discharge current controlled by the control circuit based on the patient-dependent electrical parameter (such as patient impedance) as sensed by the sensor during the sensing pulse portion. The discharge of the charge storage device occurs without the necessity of recharging the charge storage device between the sensing pulse portion and the therapeutic discharge portion of the current waveform.

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Sudbury, MA, United States of America

Shervin Ayati