Systems, apparatus, and methods for conveying biomedical signals between a patient and monitoring and treatment devices

• US 10,645,017 B2
• Filed: 11/19/2018
• Issued: 05/05/2020
• Est. Priority Date: 05/09/2018
• Status: Active Grant

• Current Assignee: BioSig Technologies, Inc.
• Original Assignee: BioSig Technologies, Inc.
• Inventors: Drakulic, Budimir S., Fakhar, Sina, Foxall, Thomas G., Vlajinic, Branislav
• Primary Examiner(s): Fairchild, Mallika D
• Application Number:
  US16/195,573
• Publication Number:
  US 20190343414A1
• Time in Patent Office: 533 Days
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2562/18 Shielding or protection of sensors from environmental influences, e.g. protection from mechanical damage
• CPC Class Codes: A61B 2562/223 Optical cables therefor
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/308 for electrocardiography [ECG]
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7217 : of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61B 5/7221 : Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7225 : Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7246 : using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61B 5/742 : using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/7435 : Displaying user selection data, e.g. icons in a graphical user interface
• CPC Class Codes: G16H 40/63 : for local operation
• CPC Class Codes: H01L 2924/14335 : Digital signal processor [DSP]
• CPC Class Codes: H02H 9/04 : responsive to excess voltage lightning arrestors H01C7/12, H01C8/04, H01G9/18, H01T
• CPC Class Codes: H02H 9/045 : adapted to a particular application and not provided for elsewhere
• CPC Class Codes: H03F 2200/129 : there being a feedback over the complete amplifier
• CPC Class Codes: H03F 2200/171 : A filter circuit coupled to the output of an amplifier
• CPC Class Codes: H03F 2200/234 : the input amplifying stage being one or more operational amplifiers
• CPC Class Codes: H03F 2200/375 : Circuitry to compensate the offset being present in an amplifier
• CPC Class Codes: H03F 2200/451 : the amplifier being a radio frequency amplifier
• CPC Class Codes: H03F 2203/45116 : Feedback coupled to the input of the differential amplifier
• CPC Class Codes: H03F 2203/45528 : the FBC comprising one or more passive resistors and being coupled between the LC and the IC
• CPC Class Codes: H03F 2203/45601 : the IC comprising one or more passive resistors by feedback
• CPC Class Codes: H03F 3/45 : Differential amplifiers differential sense amplifiers G11C7/062
• CPC Class Codes: H03F 3/45475 : using IC blocks as the active amplifying circuit
• CPC Class Codes: H03F 3/68 : Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics power amplifiers using a combination of several semiconductor amplifiers H03F3/211; combinations of amplifiers using coupling networks with distributed constants H03F3/602
• CPC Class Codes: H03H 2017/0298 : DSP implementation
• CPC Class Codes: H03K 5/125 : Discriminating pulses measuring characteristics of individual pulses G01R29/02; separation of synchronising signals in television systems H04N5/08
• CPC Class Codes: H04B 1/0014 : using DSP [Digital Signal Processor] quadrature modulation and demodulation
• CPC Class Codes: H04B 1/0039 : using DSP [Digital Signal Processor] quadrature modulation and demodulation
• CPC Class Codes: H04L 43/02 : Capturing of monitoring data
• CPC Class Codes: H04L 47/50 : Queue scheduling

Abstract

Systems, apparatus, and methods are disclosed for conveying signals between a patient and monitoring and treatment devices. An EP system provides large-signal input protection and RF ablation signal noise suppression while preserving the integrity of relevant components of small signals. The EP system has a low-noise amplifier topology with minimal hardware filtering. An input protection circuit shunts to ground signals with amplitude above an ablation voltage. An RF filter circuit linearly attenuates the signals between 300 kHz and 600 kHz. A low-frequency feedback circuit drives a common mode node of the RF filter circuit for additional attenuation. A signal amplification circuit amplifies the signals between 0.01 Hz and 1000 Hz. A fast recovery circuit feeds back a low-frequency voltage signal to the signal amplification circuit to gradually reduce offset voltage of the signals. A high-resolution A/D converter converts the signals from the signal amplification circuit to clean digital signals.

Claims

1. A system for conveying biomedical signals between a patient and monitoring or treatment devices, the system comprising:

an electrocardiogram (ECG) board having a Wilson Central Terminal (WCT) and a plurality of channels, wherein each channel of the plurality of channels has a respective output and a respective input, each respective input being adapted to be coupled to a respective ECG electrode, wherein the respective ECG electrode is a respective precordial (V) electrode or a respective limb lead,

wherein each of the respective channels coupled to a given respective limb lead comprises;

a differential circuit having a common reference node, a first path and a second path, the first path coupled to the given respective limb lead and the second path coupled to the common reference node, wherein each of the first path and the second path comprises;

an input protection circuit adapted to shunt to ground a received signal of the biomedical signals that has an amplitude above a first threshold;

a radio frequency filter circuit coupled to the input protection circuit, and adapted to linearly attenuate the biomedical signals within a first frequency range between about 300 kHz and about 600 kHz; and

a feedback circuit coupled to the radio frequency filter circuit and adapted to drive a voltage at a common mode node of the radio frequency filter circuit;

a signal amplification stage coupled to each of the first path and the second path, wherein a gain of the signal amplification stage is less than or equal to about 50 within a second frequency range between about 0.01 Hz and about 1000 Hz, wherein the signal amplification stage comprises an input and an output; and

an analog-to-digital converter coupled to the output of the signal amplification stage,

wherein the respective channel coupled to the respective precordial (V) electrode comprises the first path of the input protection circuit, the radio frequency filter circuit coupled to the input protection circuit, the feedback circuit coupled to the radio frequency filter circuit, the signal amplification stage coupled to the radio frequency filter circuit, and the analog-to-digital converter coupled to the output of the signal amplification stage,

wherein the WCT is adapted to be coupled to receive signals from the respective limb leads, and output an output signal that is an average of the respective limb leads, and

wherein each respective precordial (V) electrode is referenced to the output signal of the WCT.

2. The system of claim 1, wherein the first threshold is greater than an ablation voltage amplitude.

3. The system of claim 1, wherein the respective channel coupled to the respective precordial (V) electrode or coupled to the respective limb lead further comprises a large-signal detection and fast recovery circuit coupled to the signal amplification stage and adapted to:

limit the biomedical signals that have an amplitude above a second threshold for a certain time period; and

feed back a low-frequency voltage signal to the input of the signal amplification stage to reduce offset voltage of each of the biomedical signals.

4. The system of claim 3, wherein the second threshold is about 100 mV.

5. The system of claim 3, wherein the certain time period is about 5 milliseconds.

6. The system of claim 1, wherein the WCT is adapted to be coupled to receive signals from a right arm lead, a left arm lead and a left leg lead, and adapted to have the output signal coupled to a right leg lead.

7. An electrical signal interface device for conveying biomedical signals between a patient and monitoring or treatment devices, comprising:

a differential circuit having two paths, each differential circuit path of the two paths adapted to be coupled to a respective electrode, wherein each differential circuit path comprises;

an input protection circuit adapted to shunt to ground the biomedical signals that have an amplitude above a first threshold;

a radio frequency filter circuit coupled to the input protection circuit, and adapted to linearly attenuate the amplitude of the biomedical signals within a first frequency range between about 300 kHz and about 600 kHz, wherein the radio frequency filter circuit comprises a common mode node; and

a low-frequency feedback circuit coupled to the radio frequency filter circuit and adapted to drive a voltage at the common mode node of the radio frequency filter circuit;

a signal amplification stage coupled to each differential circuit path and comprising an output, wherein a total gain of the signal amplification stage is less than or equal to about 50 within a second frequency range between about 0.01 Hz and about 1000 Hz of the biomedical signals; and

an analog-to-digital converter coupled to an output of the signal amplification stage.

8. The electrical signal interface device of claim 7, further comprising a buffer circuit coupled to the radio frequency filter circuit.

9. The electrical signal interface device of claim 8, further comprising a DC signal block element coupled to the buffer circuit.

10. The electrical signal interface device of claim 9, wherein the DC signal block element is a capacitor.

11. The electrical signal interface device of claim 7, further comprising a shield drive circuit coupled to the low frequency feedback circuit, wherein the shield drive circuit is adapted to connect the common mode node to a shield of the respective electrode.

12. The electrical signal interface device of claim 7, further comprising a large-signal detection and fast recovery circuit coupled to the signal amplification stage and adapted to:

limit the biomedical signals that have the amplitude above a second threshold for a certain time period; and

feed back a low-frequency voltage signal to an input of the signal amplification stage to reduce offset voltage of each of the biomedical signals.

13. The electrical signal interface device of claim 12, wherein the second threshold is about 100 mV.

14. The electrical signal interface device of claim 12, wherein the certain time period is about 5 milliseconds.

15. The electrical signal interface device of claim 7, wherein the signal amplification stage comprises a plurality of operational amplifiers.

16. The electrical signal interface device of claim 15, wherein the plurality of operational amplifiers comprises:

a first operational amplifier stage having at least a first and a second operational amplifier, wherein the first operational amplifier stage has a first gain greater than one,

a third operational amplifier having a second gain of about one, and

a fourth operational amplifier having a third gain of less than one, wherein total gain comprises the first gain, the second gain, and the third gain.

17. The electrical signal interface device of claim 16, wherein the third operational amplifier is a first differential operational amplifier.

18. The electrical signal interface device of claim 17, wherein the fourth operational amplifier is a second differential operational amplifier.

19. The electrical signal interface device of claim 7, wherein the first threshold is above an ablation voltage amplitude.

20. The electrical signal interface device of claim 7, wherein the radio frequency filter circuit is adapted to linearly attenuate the amplitude of the biomedical signals within the first frequency range by at least about 75%.

21. The electrical signal interface device of claim 7, wherein the radio frequency filter circuit is adapted to linearly attenuate the amplitude of the biomedical signals within the first frequency range by at least about 90%.

22. The electrical signal interface device of claim 7, wherein the respective electrode that each differential circuit path of the two paths is adapted to be connected to is a surface electrocardiogram (ECG) electrode adapted to attach to skin of the patient.

23. The electrical signal interface device of claim 7, wherein the respective electrode that each differential circuit path of the two paths is adapted to be connected to is an intracardiac (IC) electrode.

24. The electrical signal interface device of claim 7, wherein total gain of the signal amplification stage is less than or equal to about 20.

25. The electrical signal interface device of claim 7, wherein the analog-to-digital converter has a resolution greater than 16 bits.

26. A method of conveying biomedical signals between a patient and monitoring or treatment devices, comprising:

receiving the biomedical signals as differential signals from respective electrodes;

shunting to ground the received differential signals that have an amplitude above a first threshold;

attenuating the amplitude of the received differential signals, using a radio frequency filter circuit comprising a common mode node, within a first frequency range between about 300 kHz and about 600 kHz;

driving a voltage at the common mode node of the radio frequency filter circuit using a feedback circuit coupled to the radio frequency filter circuit; and

amplifying the received differential signals within a second frequency range between about 0.01 Hz and about 1000 Hz at a gain less than or equal to about 50.

27. The method of claim 26, further comprising converting the received differential signals from an analog domain to a digital domain.

28. The method of claim 26, wherein the first threshold is greater than an ablation voltage amplitude.

29. The method of claim 26, wherein the attenuating comprises linearly attenuating the received differential signals.

30. A method of conveying biomedical signals between a patient and monitoring or treatment devices, comprising:

receiving, by an input protection circuit, the biomedical signals as differential signals from respective electrodes attached to the patient;

shunting to ground, by the input protection circuit, the differential signals having an amplitude above a first threshold greater than an ablation voltage amplitude;

linearly attenuating, by a radio frequency filter circuit comprising a common mode node, the differential signals within a first frequency range between about 300 kHz and about 600 kHz;

feeding back, by a low-frequency feedback circuit, a voltage to drive the common mode node of the radio frequency filter circuit for additional attenuation of the attenuated differential signals;

amplifying and outputting, by a signal amplification circuit comprising an input and an output, the differential signals within a second frequency range between about 0.01 Hz and about 1000 Hz at a gain less than or equal to about 50;

limiting, by a large-signal detection and fast recovery circuit, the differential signals that have the amplitude above a second threshold for a certain period of time;

feeding back, by the large-signal detection and fast recovery circuit, a low-frequency voltage signal to the input of the signal amplification circuit to reduce offset voltage of each of the differential signals; and

converting, by an analog-to-digital converter, the differential signals output by the signal amplification circuit, from an analog domain to a digital domain.