Self-Authenticating Electrocardiography Monitoring Circuit

• US 20150087950A1
• Filed: 11/15/2013
• Published: 03/26/2015
• Est. Priority Date: 09/25/2013
• Status: Active Grant

• Current Assignee: Bardy Diagnostics, Inc. (Baxter International Inc.)
• Original Assignee: Bardy Diagnostics, Inc. (Baxter International Inc.)
• Inventors: Felix, Jason, Bardy, Gust H., Bishay, Jon Mikalson
• Granted Patent: US 9,655,538 B2
• Time in Patent Office: Days
• US Class Current: 600/382
• CPC Class Codes: A61B 2562/08 Sensors provided with means for identification, e.g. barcodes or memory chips
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/259 using conductive adhesive means, e.g. gels
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/335 using integrated circuit memory devices
• CPC Class Codes: A61B 5/6823 Trunk, e.g., chest, back, abdomen, hip

Abstract

Physiological monitoring can be provided through a wearable monitor that includes two components, a flexible extended wear electrode patch and a removable reusable monitor recorder. The wearable monitor sits centrally (in the midline) on the patient'"'"'s chest along the sternum oriented top-to-bottom. The placement of the wearable monitor in a location at the sternal midline (or immediately to either side of the sternum) benefits extended wear by removing the requirement that ECG electrodes be continually placed in the same spots on the skin throughout the monitoring period. Instead, the patient can place an electrode patch anywhere within the general region of the sternum. Ensuring that the quality level of ECG recording remains constant over an extended period of time is provided through self-authentication of electrode patches. The monitor recorder implements a challenge response scheme upon being connected to an electrode patch. Failing self-authentication, the monitor recorder signals an error condition.

Claims

1. An extended wear electrocardiography and physiological sensor monitor recorder with self-authenticating electrocardiography monitoring circuit, comprising:

a sealed housing adapted to be removably secured into a non-conductive receptacle on a disposable extended wear electrode patch; and

an electronic circuitry comprised within the sealed housing, comprising;

an externally-powered micro-controller operable to execute under micro programmable control and to authenticate the disposable extended wear electrode patch during power up of the electronic circuitry;

an electrocardiographic front end circuit electrically interfaced to the micro-controller and operable to sense electrocardiographic signals through electrocardiographic electrodes provided on the disposable extended wear electrode patch; and

an externally-powered flash memory electrically interfaced with the micro-controller and operable to store samples of the electrocardiographic signals.

2. An electrocardiography and physiological sensor monitor recorder according to claim 1, further comprising:

a pair of electrical contacts external to the sealed housing and electrically connected to the micro-controller;

a cryptographic circuit provided on the disposable extended wear electrode patch;

a pair of electrical pads external to the disposable extended wear electrode patch and disposed to operatively couple with the pair of electrical contacts, the electrical pads further electrically interfaced via circuit traces to the cryptographic circuit; and

the micro-controller operable to issue a challenge to the cryptographic circuit to which the cryptographic circuit is operable to provide a response.

3. An electrocardiography and physiological sensor monitor recorder according to claim 2, further comprising:

at least one of a private key and a precomputed digested securely stored by the micro-controller and by the disposable extended wear electrode patch, which is exchanged as part of the challenge and the response.

4. An electrocardiography and physiological sensor monitor recorder according to claim 1, further comprising:

a download station comprising;

a non-conductive receptacle adapted to removably receive the monitor recorder; and

a download station controller operable to interface with the micro-controller of the electronic circuitry;

a computer system operatively coupled to the download station controller and centrally accessible over a data communications network and operable to request the micro-controller to issue a challenge to a cryptographic circuit to which the cryptographic circuit is operable to provide a response; and

a server computer system centrally accessible over the data communications network and operable to interface with the computer system to receive the challenge from and to authorize additional functionality in the electronic circuitry.

5. An electrocardiography and physiological sensor monitor recorder according to claim 4, further comprising:

a user interface provided by a computer system centrally accessible over the data communications network through which a patient can select the additional functionality in the electronic circuitry.

6. An electrocardiography and physiological sensor monitor recorder according to claim 5, further comprising:

a subscription service implemented by a server that controls the purchasing of the additional functionality in the electronic circuitry by the patient.

7. An electrocardiography and physiological sensor monitor recorder according to claim 1, the disposable extended wear electrode patch further comprising:

a flexible backing formed of an elongated strip of stretchable material with a narrow longitudinal midsection and, on each end, a contact surface at least partially coated with an adhesive dressing provided as a crimp relief;

a pair of electrocardiographic electrodes conductively exposed on the contact surface of each end of the elongated strip;

the non-conductive receptacle adhered to an outward-facing surface of the elongated strip and comprising a plurality of electrical pads; and

a flexible circuit affixed on each end of the elongated strip as a strain relief and comprising a pair of circuit traces electrically coupled to the pair of the electrocardiographic electrodes and a pair of the electrical pads.

8. An extended wear electrocardiography and physiological sensor monitor with self-authenticating electrocardiography monitoring circuit, comprising:

a disposable extended wear electrode patch comprising;

a flexible backing formed of an elongated strip of stretchable material with a narrow longitudinal midsection and, on each end, a contact surface at least partially coated with an adhesive dressing provided as a crimp relief;

a pair of electrocardiographic electrodes conductively exposed on the contact surface of each end of the elongated strip, respectively;

a non-conductive receptacle adhered to an outward-facing surface of the elongated strip and comprising a plurality of electrical pads;

a flexible circuit affixed on each end of the elongated strip as a strain relief and comprising a pair of circuit traces electrically coupled to the pair of the electrocardiographic electrodes and a pair of the electrical pads; and

a cryptographic circuit electrically coupled to another pair of the electrical pads; and

a reusable electrocardiography monitor having a sealed housing adapted to be removably secured into the non-conductive receptacle and comprising;

a micro-controller operable to execute under micro programmable control and electrically interfaced to an electrocardiographic front end circuit that is operable to sense electrocardiographic signals through the electrocardiographic electrodes via the pair of the electrical pads, the micro-controller further operable to authenticate the disposable extended wear electrode patch through the cryptographic circuit via the another pair of the electrical pads; and

flash memory electrically interfaced with the micro-controller and operable to store samples of the electrocardiographic signals.

9. An electrocardiography and physiological sensor monitor according to claim 8, wherein the electrocardiographic front end circuit is optimized to sense P-wave signals in the electrocardiographic signals.

10. An electrocardiography and physiological sensor monitor according to claim 8, further comprising:

a battery comprised on the disposable extended wear electrode patch and electrically interfaced via battery leads to a pair of the electrical pads; and

at least one of;

the micro-controller operable to draw power from the battery via the pair of the electrical pads; and

the flash memory operable to draw power from the battery via the pair of the electrical pads.

11. An electrocardiography and physiological sensor monitor according to claim 8, further comprising:

a battery comprised on the disposable extended wear electrode patch and electrically interfaced via battery leads to a pair of the electrical pads, the capacity of the battery being selected to support additional electrical components without affecting operation of the reusable electrocardiography monitor.

12. An electrocardiography and physiological sensor monitor according to claim 8, further comprising:

a download station comprising;

a non-conductive receptacle adapted to removably receive the monitor recorder; and

a download station controller operable to interface with the micro-controller of the reusable electrocardiography monitor;

a computer system operatively coupled to the download station controller and centrally accessible over a data communications network and operable to request the micro-controller to issue a challenge to the cryptographic circuit to which the cryptographic circuit is operable to provide a response; and

a server computer system centrally accessible over the data communications network and operable to interface with the computer system to receive the challenge from and to authorize additional functionality in the reusable electrocardiography monitor.

13. An electrocardiography and physiological sensor monitor according to claim 12, further comprising:

a user interface provided by a computer system centrally accessible over the data communications network through which a patient can select the additional functionality in the reusable electrocardiography monitor.

14. An electrocardiography and physiological sensor monitor according to claim 13, further comprising:

a subscription service implemented by a server that controls the purchasing of the additional functionality in the reusable electrocardiography monitor by the patient.

15. An electrocardiography and physiological sensor monitor according to claim 8, further comprising at least one of:

a feedback output component comprised in the reusable electrocardiography monitor and electrically interfaced with the micro-controller; and

a feedback input component comprised in the reusable electrocardiography monitor and externally wearer-operable from outside the sealed housing, the feedback input further electrically interfaced with the micro-controller.