Subcutaneous cardiac signal discrimination employing non-electrophysiologic signal

• US 9,655,540 B2
• Filed: 01/03/2011
• Issued: 05/23/2017
• Est. Priority Date: 04/11/2003
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Haefner, Paul
• Primary Examiner(s): Alter, Alyssa M
• Application Number:
  US12/983,565
• Publication Number:
  US 20110098587A1
• Time in Patent Office: 2,332 Days
• Field of Search: 600508, 600513
• 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. The device of claim 1, wherein the sensor comprises a blood oxygen sensor, a blood volume sensor, an acoustic sensor, a pressure transducer, or an accelerometer.

12. The device of claim 1, wherein the device defines an extrathoracic defibrillator.

13. The device of claim 1, wherein the sensor is configured to sense non-electrical cardiac activity and to generate information associated with the sensed nonelectrical cardiac activity, and the device further comprises:

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;

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

14. The device of claim 13, wherein the non-electrical cardiac activity comprises a temporal location of a peak heart-sound.

15. The device of claim 13, wherein the processor is further configured to identify the detected electrical signal as a cardiac signal indicative of a cardiac condition.

16. The device of claim 13, wherein the processor is further configured to identify the cardiac signal from the plurality of electrical signals detected at the subcutaneous non-intrathoracic location using the detection window.

17. The device of claim 16, wherein the processor is further configured to detect a QRS complex within the detection window.

18. The device of claim 13, wherein the processor is further configured to correlate the received non-electrical cardiac activity information with the electrical signal.

19. The device of claim 13, wherein the processor is further configured to:

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

identify the cardiac signal based on the time separation determination.

20. The device of claim 13, wherein the processor is further configured to identify the detected electrical signal as a cardiac signal indicative of a cardiac condition and to deliver an cardiac electrical therapy to treat the cardiac condition.