Subcutaneous Cardiac Signal Discrimination Employing Non-Electrophysiologic Signal

• US 20110098587A1
• Filed: 01/03/2011
• Published: 04/28/2011
• Est. Priority Date: 04/11/2003
• Status: Active Grant

• Current Assignee: Paul Haefner
• Original Assignee: Paul Haefner
• Inventors: Haefner, Paul
• Granted Patent: US 9,655,540 B2
• Time in Patent Office: Days
• US Class Current: 600/528
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/308 for electrocardiography [ECG]
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

A cardiac monitoring and/or stimulation system includes a housing coupled to a plurality of electrodes configured for subcutaneous non-intrathoracic sensing. A signal processor receives a plurality of composite signals associated with a plurality of sources, separates a signal from the plurality of composite signals, and identifies the separated signal as a cardiac signal using information derived from a non-electrophysiologic sensor, such as an accelerometer or acoustic transducer. The signal processor may iteratively correlate separated signals from the plurality of composite signals with a non-electrophysiologic sensor signal until the cardiac signal is identified.

Claims

1. A device, comprising:

an implantable housing;

a plurality of subcutaneous non-intrathoracic electrodes configured to sense a plurality of electrical signals;

a sensor that senses a non-electrophysiologic signal; and

a signal processor provided in the housing and coupled to the sensor and the plurality of subcutaneous non-intrathoracic electrodes, the processor configured to initiate a detection window at a start time determined from use of the non-electrophysiologic signal, and to identify a cardiac signal from the plurality of electrical signals using the detection window.

2. The device of claim 1, wherein the sensor comprises an accelerometer.

3. The device of claim 1, wherein the sensor comprises an acoustic transducer.

4. The device of claim 1, wherein the sensor is provided in or on the housing.

5. The device of claim 4, wherein the sensor comprises a microphone.

6. The device of claim 1, further comprising a lead coupled to the plurality of subcutaneous non-intrathoracic electrodes.

7. The device of claim 1, further comprising a plurality of leads, wherein at least one of the plurality of leads is coupled to an array of electrodes.

8. The device of claim 1, further comprising energy delivery circuitry configured to deliver a cardiac electrical therapy based at least in part on the cardiac signal identified using the detection window.

9. The device of claim 8, wherein the cardiac therapy comprises a cardiac pacing therapy.

10. The device of claim 8, wherein the cardiac therapy comprises a cardiac defibrillation therapy.

11. A method, comprising:

detecting an electrical signal at a subcutaneous non-intrathoracic location, the electrical signal associated with a plurality of sources;

receiving information associated with non-electrical cardiac activity;

initiating a detection window at a start time determined from use of the received non-electrical cardiac activity information, the detection window defined at least in part by a start time prior to the non-electrical cardiac activity;

examining at least a portion of the electrical signal using the detection window; and

identifying the electrical signal as a cardiac signal based on the examination.

12. The method of claim 11, wherein the non-electrical cardiac activity comprises a temporal location of a peak heart-sound.

13. The method of claim 11, further comprising identifying the detected electrical signal as a cardiac signal indicative of a cardiac condition.

14. The method of claim 11, wherein identifying the cardiac signal comprises identifying the cardiac signal from a plurality of electrical signals detected at the subcutaneous non-intrathoracic location using the detection window.

15. The method of claim 14, further comprising detecting a QRS complex within the detection window.

16. The method of claim 11, further comprising correlating the received non-electrical cardiac activity information with the electrical signal.

17. The method of claim 11, further comprising:

determining a time separation between a peak of the non-electrical cardiac activity and a peak of the electrical signal; and

identifying the cardiac signal based on the time separation determination.

18. The method of claim 11, further comprising identifying the detected electrical signal as a cardiac signal indicative of a cardiac condition and treating the cardiac condition.

19. The method of claim 18, wherein treating the cardiac condition comprises one or more of delivering a cardiac electrical therapy, a cardiac pacing therapy, and a cardiac defibrillation therapy based at least in part on the cardiac signal identified from the examination.

20. A device, comprising:

an implantable housing;

a plurality of subcutaneous non-intrathoracic electrodes;

a detector provided in the housing and coupled to the plurality of subcutaneous non-intrathoracic electrodes, the detector configured to detect an electrical signal sensed by the plurality of subcutaneous non-intrathoracic electrodes and associated with a plurality of sources;

a sensor configured to sense non-electrical cardiac activity and to generate information associated with the sensed non-electrical cardiac activity; and

a processor coupled to the detector and the sensor, the processor configured to examine at least a portion of the electrical signal using a detection window defined at least in part by a start time that is prior to the non-electrical cardiac activity, the processor configured to identify a cardiac signal based on the examination.