Granted Patent B2

US 12,642,981 · App. 18/446,391 · Granted Jun 2, 2026

Inventors: David P. Finch (Bothell, WA); Leo J. Gilbert (Kirkland, WA); Joseph L. Sullivan (Kirkland, WA); Jaeho Kim (Redmond, WA); John Wei-Hao Huang (Bothell, WA); Brian J. Bennett (Redmond, WA); Kenneth F. Cowan (Everett, WA)

Assignee: West Affum Holdings DAC

A61N1/3912A61N1/3904A61N1/3937A61N1/3987

Abstract

Claims (67)

1 . A wearable cardioverter defibrillator (WCD) for an ambulatory patient, comprising:

a support structure configured to be worn by the ambulatory patient;

WCD circuitry, operatively coupled to the support structure, including,

a power source;

a charger, coupled to the power source;

an energy storage module, operatively coupled to the charger; and

output circuitry, coupled to the energy storage module;

first and second therapy electrodes coupled to the output circuitry and configured to be maintained on a body of the ambulatory patient when the support structure is worn by the ambulatory patient; and

control circuitry operatively coupled to the charger, the energy storage module, and the output circuitry, the control circuitry configured to cause the WCD circuitry to emulate a current source with an adjustable current level to generate pacing pulses delivered to the first and second therapy electrodes.

2 . The WCD of claim 1 , further comprising:

at least one sensor configured to sense a parameter of the ambulatory patient; and

a measurement circuit, operatively coupled to the at least one sensor and the control circuitry and configured to render a patient input responsive to the sensed parameter,

wherein the control circuitry is configured to detect arrhythmias that are treated with the pacing pulses and control when the pacing pulses are delivered to the first and second therapy electrodes.

3 . The WCD of claim 2 , wherein the control circuitry includes:

one or more processors; and

one or more software modules comprising instructions configured to be executed on at least one of the one or more processors to implement control functions including generating the pacing pulses.

4 . The WCD of claim 3 , wherein the one or more software modules include a pacing module configured to receive one or more sensed parameters from the measurement circuit, detect arrhythmias treated with the pacing pulses, and provide control input to the output circuitry to control timing of the pacing pulses.

5 . The WCD of claim 3 , wherein the one or more software modules include a charge rate control module comprising instructions to, upon execution on a processor of the one or more processors, control charging of the energy storage module.

6 . The WCD of claim 5 , further comprising a pulse width modulation (PWM) module implemented in at least one of software and hardware, wherein the PWM module is configured to provide a PWM control signal to the charger.

7 . The WCD of claim 6 , wherein the PWM control signal comprises a pacing signal to cause the charger to generate the pacing pulses, and wherein at least one of a frequency and duty cycle of the PWM control signal is programmatically controlled in software.

8 . The WCD of claim 1 , wherein the WCD circuitry is configured to:

initiate generation of pacing pulses having a voltage level;

measure an impedance load of the ambulatory patient; and

adjust the voltage level of the pacing pulses using the measured impedance load.

9 . The WCD of claim 1 , wherein the WCD circuitry is configured to:

generate one or more defibrillator shocks to the ambulatory patient; and

perform post shock pacing during which the pacing pulses are delivered to the ambulatory patient via the first and second therapy electrodes.

10 . The WCD of claim 1 , wherein the charger includes at least one of constant energy and constant current configurations to cover a range of impedances.

11 . An apparatus, including circuitry comprising:

an energy storage module;

a charger, configured to be coupled to a battery and provide a charge to the energy storage module,

an output circuit block, operatively coupled to the charger and the energy storage module, the output circuit block having at least one output configured to be coupled to first and second therapy electrodes;

a processor block, operatively couple to the charger, the energy storage module, and the output circuit block, the processor block including one or more processing elements on which instructions are executed and at least one memory in which the instructions are stored; and

one or more software modules comprising the instructions configured to be executed by at least one of the one or more processing elements to enable the apparatus that includes the circuitry to emulate a current source with an adjustable current level to generate pacing pulses delivered to the first and second therapy electrodes, wherein the apparatus is further configured to:

initiate generation of pacing pulses having a voltage level;

measure an impedance load of an ambulatory patient; and

adjust the voltage level of the pacing pulses using the measured impedance load.

12 . The apparatus of claim 11 , wherein the output circuit block includes:

a bridge configured to receive four drive signals output from the processor block; and

an impedance drive, coupled to a pair of outputs from the bridge, the pair of outputs configured to be coupled to the first and second therapy electrodes.

13 . The apparatus of claim 11 , wherein the apparatus is configured to be implemented in a wearable cardioverter defibrillator (WCD) for an ambulatory patient, the WCD including at least one sensor configured to sense a parameter of the ambulatory patient, the apparatus further comprising a measurement circuit, operatively coupled to the at least one sensor and providing one or more sensor inputs to the processing block, and

wherein execution of the instructions enables the apparatus to detect arrhythmias of the ambulatory patient that are treated with the pacing pulses and control when the pacing pulses are delivered to the first and second therapy electrodes.

14 . The apparatus of claim 11 , wherein the apparatus is further configured to:

measure a voltage characteristic of a pacing pulse; and

use the voltage characteristic as a parameter to adjust the voltage level of a next pacing pulse.

15 . The apparatus of claim 11 , further comprising a pulse width modulation (PWM) module implemented in at least one of software and hardware, wherein the PWM module is configured to provide a PWM control signal to the charger.

16 . The apparatus of claim 11 , wherein the energy storage module includes a capacitor, and wherein execution of the instructions enables the apparatus to generate the pacing pulses delivered to the first and second therapy electrodes in a manner that does not charge the capacitor between pulses.

17 . A method implemented by a wearable cardioverter defibrillator (WCD) worn by an ambulatory patient, the WCD including a battery coupled to WCD circuitry including a charger, an energy storage module, control circuitry, and output circuitry coupled to first and second therapy electrodes in contact with the ambulatory patient, the method comprising:

controlling the charger with the control circuitry to emulate a current source;

outputting pacing pulses to the first and second therapy electrodes without the current source;

initiating generation of pacing pulses having a voltage level;

measuring an impedance load of the ambulatory patient; and

adjusting the voltage level of the pacing pulses using the measured impedance load.

18 . The method of claim 17 , wherein the charger is a constant energy charger, further comprising emulating the current source with the constant energy charger.

19 . The method of claim 17 , wherein the control circuitry includes one or more processing elements, further comprising executing software instructions on at least one processing element of the one or more processing elements to generate control signals to the control operation of the charger.

20 . The method of claim 17 , wherein the WCD includes one or more sensors, the method further comprising:

receiving one or more signals from the one or more sensors;

determining the impedance load based on the one or more signals that are received; and

adjusting the pacing pulses to deliver pacing pulses having a desired current.

21 . The method of claim 17 , further comprising:

measuring a voltage characteristic of a pacing pulse; and

using the voltage characteristic as a parameter to adjust the voltage level of a next pacing pulse.

22 . The method of claim 17 , wherein the energy storage module comprises a capacitor, the method further comprising employing the charger to provide an output without charging the capacitor between pulses.

23 . The method of claim 17 , wherein the WCD includes one or more sensors, the method further comprising:

receiving one or more signals from the one or more sensors;

processing the one or more signals to detect an arrhythmia, and in response thereto,

implementing a pacing routing from among multiple pacing routines based on the detected arrhythmia.

Assignments (2)

Continuity (2)

References Cited (189)