ECG ELECTRODE CONTACT QUALITY MEASUREMENT SYSTEM

• US 20100007413A1
• Filed: 11/02/2007
• Published: 01/14/2010
• Est. Priority Date: 11/10/2006
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Herleikson, Earl C.
• Granted Patent: US 8,086,300 B2
• Time in Patent Office: Days
• US Class Current: 330/124.R
• CPC Class Codes: A61B 5/276 Protection against electrode failure
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/301 providing electrical separation, e.g. by using isolating transformers or optocouplers
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

A system and method are provided for generating output signals indicative of contact quality of a plurality of electrodes coupled to a patient. A signal generator coupled to a reference electrode injects an alternating signal into the patient. A plurality of differential amplifiers, each coupled to a respective one of the plurality of electrodes to detect an input signal from the patient, are operable to output a respective output signal in response to a respective input signal. The output signal generated by the respective differential amplifier is indicative of contact quality for the respective electrode.

Claims

1. A system for generating output signals indicative of contact quality of a plurality of electrodes coupled to a patient, the system comprising:

a signal generator coupled to a reference electrode and operable to output an alternating signal; and

a plurality of differential amplifiers, each having a first input coupled to a respective electrode of the plurality of electrodes and further having a second input coupled to a floating common node, each differential amplifier operable to output a respective output signal in response to an input signal applied to the respective first input, the output signal indicative of contact quality for the respective electrode.

2. The system of claim 1, further comprising:

a feedback amplifier having a first input coupled to the signal generator and an output coupled to the reference electrode, the feedback amplifier further having a second input coupled to the outputs of the plurality of differential amplifiers, each output coupled to the second output through a respective resistor.

3. The system of claim 2, further comprising:

an active filter network coupled to the plurality of differential amplifiers configured to filter the respective input signals in generating the respective output signals.

4. The system of claim 3 wherein the floating common node is a first floating common node and the active filter network comprises:

coupled to the output of each differential amplifier, a respective first capacitor-resistor pair coupled in parallel between the respective output and a second floating common node;

coupled to the second input of each differential amplifier, a respective second capacitor-resistor pair coupled in parallel between the respective second input and the second floating common node; and

coupled to the second input of each differential amplifier, a respective third capacitor-resistor pair coupled in series between the respective second input and the first floating common node.

5. The system of claim 4 wherein the resistor of the second capacitor-resistor pair are equal for each differential amplifier and the resistor of the third capacitor-resistor pair are equal for each differential amplifier.

6. The system of claim 1 wherein each of the plurality of differential amplifiers are coupled to have a common mode gain of unity.

7. The system of claim 1 wherein the plurality of differential amplifiers comprises three differential amplifiers.

8. The system of claim 1 wherein the signal generator comprises a pseudo-random noise generator.

9. The system of claim 1 wherein the system is included in an ECG measurement system operable to acquire ECG signals.

10. A system for generating output signals indicative of contact quality of a plurality of electrodes coupled to a patient, the system comprising:

a signal generator coupled to a reference electrode and operable to output an alternating signal; and

a differential array amplifier having a plurality of inputs and a corresponding plurality of differential amplifier stages, each input configured to be coupled to a respective one of the plurality of electrodes, each differential amplifier stage including a differential amplifier having a first input coupled to the respective input, a second input coupled to a first floating common node, and an output coupled to a second floating common node, each differential amplifier stage further including a first capacitor-resistor pair coupled in parallel between the output and the second floating common node, a second capacitor-resistor pair coupled in parallel between the second input and the second floating common node, and a third capacitor-resistor pair coupled in series between the second input and the first floating common node, the differential array amplifier operable to output a respective output signal in response to a respective input signal applied to the respective input, the respective output signal indicative of contact quality for the respective electrode.

11. The system of claim 10 wherein the differential array amplifier further including a feedback amplifier having a first input coupled to the signal generator and an output coupled to the reference electrode, the feedback amplifier further having a second input coupled to the outputs of the plurality of differential amplifiers, each output coupled to the second output of the feedback amplifier through a respective resistor.

12. The system of claim 10 wherein each of the plurality of differential amplifiers are coupled to have a common mode gain of unity.

13. The system of claim 10 wherein the system is included in an ECG measurement system operable to acquire ECG signals.

14. A method of determining contact quality of a plurality of electrodes coupled to a patient, the method comprising:

applying an alternating signal to the patient;

detecting a respective input signal from the patient for each of the electrodes, each of the electrodes coupled to a first input of a respective differential amplifier, a second input of each differential amplifier coupled to a floating common node;

generating a respective output signal in response to detecting the respective input signal;

evaluating each of the respective output signals; and

determining contact quality of an electrode from a phase shift and attenuation of the respective output signal generated in response to the respective input signal.