Subcutaneous cardiac sensing and stimulation system employing blood sensor

• US 20080091242A1
• Filed: 10/17/2007
• Published: 04/17/2008
• Est. Priority Date: 04/11/2003
• Status: Active Grant

• Current Assignee: Apurv Kamath, Darrell Wagner, Marina Brockway, Paul Haefner
• Original Assignee: Apurv Kamath, Darrell Wagner, Marina Brockway, Paul Haefner
• Inventors: Haefner, Paul, Brockway, Marina, Kamath, Apurv, Wagner, Darrell
• Granted Patent: US 8,024,039 B2
• Time in Patent Office: Days
• US Class Current: 607/6
• CPC Class Codes: A61B 17/3203 Fluid jet cutting instruments
• CPC Class Codes: A61B 17/3415 for introducing tubes or catheters, e.g. gastrostomy tubes, drain catheters A61B17/3417 takes precedence; body piercing catheter guide needles A61M25/06
• CPC Class Codes: A61B 17/3417 Details of tips or shafts, e.g. grooves, expandable, bendable; Multiple coaxial sliding cannulas, e.g. for dilating syringe needles A61M5/32; dilators A61M29/00
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2017/00247 Making holes in the wall of the heart, e.g. laser Myocardial revascularization
• CPC Class Codes: A61B 2017/320044 Blunt dissectors
• CPC Class Codes: A61B 2017/320084 Irrigation sleeves
• CPC Class Codes: A61B 2018/00392 Transmyocardial revascularisation
• CPC Class Codes: A61B 2090/3945 Active visible markers, e.g. light emitting diodes
• CPC Class Codes: A61B 2090/3979 infrared
• CPC Class Codes: A61B 2217/005 with suction drainage system
• CPC Class Codes: A61B 2217/007 with irrigation system
• CPC Class Codes: A61B 90/30 Devices for illuminating a surgical field, the devices having an interrelation with other surgical devices or with a surgical procedure
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/0568 with drug delivery
• CPC Class Codes: A61N 1/0587 Epicardial electrode systems; Endocardial electrodes piercing the pericardium
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3925 : Monitoring; Protecting
• CPC Class Codes: A61N 1/3956 : Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/3962 : in combination with another heart therapy
• CPC Class Codes: A61N 1/39622 : Pacing therapy
• CPC Class Codes: A61N 1/3987 : characterised by the timing or triggering of the shock

Abstract

Cardiac systems and methods using ECG and blood information for arrhythmia detection and discrimination. Detection circuitry is configured to produce an ECG. An implantable blood sensor configured to produce a blood sensor signal is coupled to a processor. The processor is coupled to the detection and energy delivery circuitry, and used to evaluate and treat cardiac rhythms using both the cardiac electrophysiologic and blood sensor signals. The blood sensor is configured for subcutaneous non-intrathoracic placement and provided in or on the housing, on a lead coupled to the housing, and/or separate to the housing and coupled to the processor via hardwire or wireless link. The blood sensor may be configured for optical sensing, using a blood oxygen saturation sensor or pulse oximeter. A cardiac rhythm may be evaluated using the electrocardiogram signal and the blood sensor signal, and tachyarrhythmias may be treated after confirmation using the blood sense signal.

Claims

1. An implantable subcutaneous device, comprising:

a housing configured for subcutaneous non-intrathoracic placement;

detection circuitry provided in the housing and configured to produce a cardiac electrophysiologic signal;

energy delivery circuitry provided in the housing;

at least one electrode configured for subcutaneous non-intrathoracic placement and coupled to the detection and energy delivery circuitry;

an implantable blood sensor configured to produce a blood sensor signal; and

a processor provided in the housing and coupled to the blood sensor, the detection circuitry, and the energy delivery circuitry, the processor configured to discriminate between a tachyarrhythmia condition that requires cardioversion or defibrillation therapy and a condition that does not require cardioversion or defibrillation therapy using the cardiac electrophysiologic signal and the blood sensor signal, the processor configured to withhold delivery of cardioversion or defibrillation therapy in response to determining, using the blood sensor signal, that the condition does not require cardioversion or defibrillation therapy.

2. The device of claim 1, wherein the processor is configured to detect the tachyarrhythmia condition using the cardiac electrophysiologic signal and confirm presence of the tachyarrhythmia condition using the blood sensor signal.

3. The device of claim 1, wherein the processor is configured to identify a cardiac rhythm as the tachyarrhythmia condition using the cardiac electrophysiologic signal and a relative change in the blood sensor signal.

4. The device of claim 1, wherein the processor is configured to activate the blood sensor and evaluate the tachyarrhythmia condition using the cardiac electrophysiologic signal and the blood sensor signal in response to detecting the tachyarrhythmia condition using the cardiac electrophysiologic signal.

5. The device of claim 1, wherein the processor is configured to deliver the therapy to treat the tachyarrhythmia condition in response to confirming presence of the tachyarrhythmia condition, the processor configured to deactivate the blood sensor before or after delivery of the therapy.

6. The device of claim 1, wherein the processor is configured to discriminate between the tachyarrhythmia condition that requires the therapy and noise.

7. The device of claim 1, wherein the device comprises a plurality of electrodes, and the processor is configured to detect the tachyarrhythmia condition by analyzing an activation pattern of the cardiac electrophysiologic signal using the plurality of electrodes.

8. The device of claim 1, wherein the blood sensor comprises optical signal sensing circuitry, a blood oxygen saturation sensor, a pulse oximeter or photoplethysmography circuitry.

9. The device of claim 1, wherein the processor is configured, in response to detecting an unidentifiable cardiac rhythm using the cardiac electrophysiologic signal, to activate the blood sensor to facilitate identification of the unidentifiable cardiac rhythm using the blood sensor signal.

10. The device of claim 1, wherein the processor is configured to determine a hemodynamic state using the cardiac electrophysiologic signal and the blood sensor signal.

11. The device of claim 1, wherein the processor is configured to use the blood sensor signal for performing at least one of assessing cardiac function, assessing oxygen saturation, or assessing afterload.

12. A tachyarrhythmia evaluation method, comprising:

sensing an electrocardiogram signal at a subcutaneous non-intrathoracic location;

acquiring a blood sense signal from a subcutaneous non-intrathoracic sensing location;

discriminating between a tachyarrhythmia condition that requires cardioversion or defibrillation therapy and a condition that does not require cardioversion or defibrillation therapy using the electrocardiogram signal and the blood sensor signal; and

withholding delivery of cardioversion or defibrillation therapy in response to determining, using the blood sensor signal, that the condition does not require cardioversion or defibrillation therapy.

13. The method of claim 12, wherein discriminating between the tachyarrhythmia condition that requires the therapy and the condition that does not require the therapy comprises detecting the tachyarrhythmia condition using the electrocardiogram signal and confirming presence of the tachyarrhythmia condition using the blood sensor signal.

14. The method of claim 12, comprising delivering the therapy to treat the tachyarrhythmia condition in response to confirming presence of the tachyarrhythmia condition using the electrocardiogram signal and the blood sensor signal.

15. The method of claim 12, wherein discriminating comprising discriminating between the tachyarrhythmia condition that requires the therapy and noise.

16. The method of claim 12, wherein discriminating between the tachyarrhythmia condition that requires the therapy and the condition that does not require the therapy comprises performing a correlation between the electrocardiogram signal and the blood sense signal.

17. The method of claim 12, wherein acquiring the blood sense signal comprises selectively powering-up and powering-down a blood sensor that produces the blood sense signal.

18. The method of claim 12, comprising determining a hemodynamic state using the electrocardiogram signal and the blood sensor signal.

19. The method of claim 12, comprising at least one of assessing cardiac function, assessing oxygen saturation, or assessing afterload using the blood sensor signal.

20. An implantable subcutaneous device, comprising:

means for sensing an electrocardiogram signal at a subcutaneous non-intrathoracic location;

means for acquiring a blood sense signal from a subcutaneous non-intrathoracic sensing location;

means for discriminating between a tachyarrhythmia condition that requires cardioversion or defibrillation therapy and a condition that does not require cardioversion or defibrillation therapy using the electrocardiogram signal and the blood sensor signal; and

means for withholding delivery of cardioversion or defibrillation therapy in response to determining, using the blood sensor signal, that the condition does not require cardioversion or defibrillation therapy.