Distributed cardiac pacing system

Abstract

The invention is entitled "Distributed cardiac pacing system". The invention discloses an apparatus comprising a relay and sampling unit, a pacing unit, a pacing detection circuit and a processor. The relay and sampling unit receives a plurality of electrocardiogram (ECG) signals sensed by respective electrodes in a patient's heart, and digitizes a first subset of the ECG signals, and forwards a second subset of the ECG signals that are not digitized over an analog line. The pacing unit outputs a pacing signal, the pacing detection circuit detects the pacing signal and outputs a trigger in response. The processor receives the trigger and an identity of an electrode of the electrodes via which the pacing signal is to be applied, and in response to identifying that the electrode via which the pacing signal is to be applied is currently associated with the digitized ECG signals, instructs the relay and sampling unit to switch the identified electrode to the analog line for communicating the pacing signal.

Description

TECHNICAL FIELD

[0001] The present invention relates generally to manipulating electrophysiological signals, and more particularly to pacing intracardiac electrophysiological signals using a catheter. BACKGROUND

[0002] Various techniques for pacing and measuring intracardiac electrophysiological signals are presented in the patent literature. For example, U.S. Patent 10,335,051 describes a cardiac mapping method that includes measuring heartbeats in signals at one or more electrodes on a catheter in response to electrical activity in a chamber of a heart, and collecting a plurality of additional data signals related to the heartbeats. A criterion is computed and used to characterize a beat morphology of the plurality of additional data signals based on a comparison of the plurality of additional data signals to a beat template. In some embodiments, cardiac pacing is used during the mapping procedure.

[0003] As another example, U.S. Patent Application Publication 2018 / 0235692 describes a high-resolution, multi-functional conformal electronic device generally having a flexible and stretchable high-density electrode array integrated with a catheter (e.g., a balloon catheter) for mapping, ablation, pacing, and sensing cardiac tissue associated with cardiac arrhythmias. The invention can precisely locate the source of arrhythmias as described above and deliver therapy from the same electrode array. This is accomplished using a capacitive sensing electrode array that can monitor and deliver electrical stimulation. SUMMARY

[0004] Exemplary embodiments of the present invention provide an apparatus that includes a relay and sampling unit, a pacing unit, a pace detection circuit, and a processor. The relay and sampling unit is configured to receive a plurality of electrocardiogram (ECG) signals sensed by respective electrodes in a patient’s heart, digitize a first subset of the ECG signals, and forward a second subset of the ECG signals that are not digitized over analog lines. The pacing unit is configured to output a pacing signal. The pace detection circuit is configured to detect the pacing signal and output a trigger in response to the pacing signal. The processor is configured to: (a) receive (i) the trigger and (ii) an identity of an electrode of the electrodes via which the pacing signal is to be applied, and (b) in response to identifying that the electrode via which the pacing signal is to be applied is currently associated with the digitized ECG signals, instruct the relay and sampling unit to switch the identified electrode to the analog lines for communicating the pacing signal.

[0005] In some exemplary embodiments, the apparatus further includes a patient interface unit (PIU) configured to accept and store the identity of the electrode via which the pacing signal is to be applied, and wherein the processor is configured to read the identity from the PIU upon the trigger by the pace detection circuit.

[0006] In some example embodiments, the relay and sampling unit is included in a dongle that connects the electrodes to the PIU.

[0007] In example embodiments, the pace detection circuit is further configured to detect that the pace signal stops and to trigger the processor in response, and wherein the processor is further configured to command the relay and sampling unit to switch the selected electrode from the analog line to the digital line upon being triggered.

[0008] According to another example embodiment of the present application, there is additionally provided a method comprising, in a relay and sampling unit, receiving a plurality of electrocardiogram (ECG) signals sensed by respective electrodes in a patient's heart, digitizing a first subset of the ECG signals, and forwarding a second subset of the ECG signals that are not digitized over an analog line. A pace signal is output using a pace unit. The pace signal is detected, and a trigger is output in response to the pace signal. In a processor, there is received (i) the trigger and (ii) an identity of an electrode via which the pace signal is to be applied. In response to identifying that the electrode via which the pace signal is to be applied is currently associated with a digitized ECG signal, instructing the relay and sampling unit to switch the identified electrode to the analog line for communicating the pace signal.

[0009] In some example embodiments, the method further comprises switching the selected electrode from the analog line to the digital line upon detecting that the pace signal stops. BRIEF DESCRIPTION OF DRAWINGS

[0010] The present application will be more fully understood from the following detailed description of the embodiments thereof, taken together with the drawings in which:

[0011] Figure 1 schematic illustration of a catheter-based cardiac pacing and electrophysiology sensing system according to example embodiments of the present application;

[0012] Figure 2 block diagram of a cardiac pacing and electrophysiology sensing device of the system of Figure 1 ; and

[0013] Figure 3 flowchart schematically illustrating a method for pacing using the device of Figure 2 according to example embodiments of the present application. DETAILED DESCRIPTION

[0014] SUMMARY

[0015] Cardiac pacing using analog catheter-based systems is relatively simple because such systems have wires that can directly conduct pacing signals between a pacing unit connected to the system and the catheter. Typically, pacing is performed by selecting a conductive wire (corresponding to a desired catheter electrode) and transmitting a pacing signal along the selected wire, where automatic pacing activation is readily provided by the control circuitry of the analog system.

[0016] Unfortunately, such traditional analog catheter-based cardiac systems are typically only able to measure a limited number of signals, such as at most tens of electrocardiogram (ECG) channels of analog signals acquired by the same number of electrodes (hereinafter also referred to as "analog connected subset of electrodes", which is set to acquire a second subset of ECG signals that are not digitized, where a first set of ECG signals are digitized to overcome short circuits in the analog wires).

[0017] However, modern diagnostic catheters can have many more electrodes within the patient's heart, such as 256 electrodes. To accommodate the additional channels of modern diagnostic catheters, signals from such catheters (e.g., 256 channel basket catheters) can be transmitted to a traditional catheter-based system via a digital communication link. The electrodes connected via digital wires are hereinafter also referred to as "digitally connected subset of electrodes", which is set to acquire a first subset of ECG signals that are digitized to overcome short circuits in the analog wires.

[0018] To transmit signals from the digitally connected subset of electrodes, for example, to an ECG recording device using a digital link, a dongle including analog-to-digital circuitry can be inserted between the diagnostic catheter and the traditional recording device. The display of the system can present such digitally transmitted ECG signals.

[0019] However, for pacing, the dongle and digital wires cannot support delivery of analog signals via electrodes selected from the digitally connected subset of electrodes (e.g., applying an excitation signal using a pacing unit).

[0020] The exemplary embodiments of the present invention described below enable pacing from electrodes selected from either the analog connected subset of catheter electrodes or the digitally connected subset of electrodes.

[0021] In some example embodiments, a pacing device is provided that includes a relay and sampling unit, a pacing unit, a pace detection circuit, and a processor. The relay and sampling unit is configured to receive a plurality of electrocardiogram (ECG) signals sensed by respective electrodes in a patient's heart (e.g., by disposing a catheter to be inserted into the heart), digitize a first subset of the ECG signals, and forward a second subset of the ECG signals that are not digitized over analog lines. The pacing unit is configured to output pacing signals, while the pace detection circuit is configured to detect the pacing signals and output a trigger in response to the pacing signals. The processor is configured to: (a) receive (i) the trigger and (ii) an identity of an electrode via which the pacing signals are to be applied, and (b) in response to identifying that the electrode via which the pacing signals are to be applied is currently associated with the digitized ECG signals, instruct the relay and sampling unit to switch the identified electrode to an analog line for communicating the pacing signals.

[0022] In example embodiments, a physician uses a patient user interface (PIU) to select an electrode. If the selected electrode pair is currently associated with the digitized ECG signals (i.e., belongs to the subset of digital connections to the electrodes), the PIU updates the processor with the identity of the electrode (e.g., with a running index between 1 and 256). Pacing signals are typically generated by the pacing unit, but they are transmitted over a dedicated analog line that is only used for the traditional subset of digital connections to the electrodes. The pace detection circuit detects the pacing signals conducted on the dedicated line and triggers the processor. Upon being triggered, the processor instructs the relay and sampling unit (hereinafter also referred to as "switching component") to switch the selected electrode pair to an analog input to which the dedicated analog pacing line in the switching component is connected (e.g., using an existing relay in the switching component) in order to enable pacing.

[0023] In example embodiments, the switching component is included in a dongle that enables the electrodes to be connected to the PIU. In another example embodiment, once pacing is over, the pace detection circuit detects the event and triggers the processor to instruct the dongle to switch the selected electrodes back from the analog input to the digital line.

[0024] Typically, the processor is programmed in software that contains specific algorithms that enable the processor to perform each of the processor-related steps and functions described above.

[0025] The disclosed technology provides a simple and effective means to enable traditional systems to use any of the multiple electrodes of modern catheters to pace heart tissue. Moreover, the disclosed technology can be used with other catheters, such as brain catheters that apply and measure electrophysiological signals related to brain activity. Thus, the disclosed technology can increase the availability of several kinds of modern catheter-based diagnostic services.

[0026] System Description

[0027] Figure 1 FIG. 1 is a schematic illustration of a catheter-based cardiac pacing and electrophysiology sensing system 20 according to an exemplary embodiment of the present application. System 20 can be, for example, the CARTO® 3 system produced by Biosense-Webster (Irvine, California). As shown, system 20 includes a catheter 21 having a shaft 22 that is navigated by a physician 30 into a heart 26 of a patient 28. In the illustrated example, physician 30 inserts shaft 22 through a sheath 23 while manipulating shaft 22 with a manipulator 32 near the proximal end of the catheter. 3system. As shown, system 20 includes a catheter 21 having a shaft 22 that is navigated by a physician 30 into a heart 26 of a patient 28. In the illustrated example, physician 30 inserts shaft 22 through a sheath 23 while manipulating shaft 22 with a manipulator 32 near the proximal end of the catheter.

[0028] In the exemplary embodiments described herein, catheter 21 can be used for any suitable diagnostic purpose, such as cardiac pacing using pacing unit 37, and electrophysiology mapping of heart 26. As shown in inset 25, a distal end of shaft 22 of catheter 21 is fitted with a multi-electrode basket catheter 40. Inset 45 shows the arrangement of multiple sensing electrodes 48 (i.e., 256 or more channels) of basket catheter 40. A proximal end of catheter 21 is connected to a console 24 by a dongle 50.

[0029] ECG recording instrument 35 can receive various analog ECG signals sensed during the procedure by an analog subset of connections of electrodes 48 and transmitted via a conventional cable 62. However, digital ECG signals sensed using a digital subset of connections of electrodes 48 can only be presented on a display of console 24.

[0030] Similarly, in system 20, there is no analog link between the digital subset of electrodes 48 of catheter 21 and pacing unit 37, since conventional cable 62 between console 24 and recording instrument 35 and pacing unit 37 only supports a limited number of electrodes selected to belong to the analog subset of electrodes.

[0031] A special composite line is provided to enable pacing unit 37 to be paced by electrodes belonging to the digital subset of electrodes. In the illustrated exemplary embodiment, the composite line includes (a) an analog pacing line 100 between pacing unit 37 and pacing detection circuit 55, and (b) an analog pacing link 110 between circuit 55 and dongle 50. When pacing from the digital subset of electrodes is required, circuit 55 triggers processor 41 to command a relay 51 within dongle 50 to switch the selected electrode into the analog input to which line 100 of dongle 50 is connected. Responsively, relay 51 within dongle 50 switches the routing of the pacing analog signal to the electrode in the selected digital connection electrode, as shown in FIG. 2. Figure 2 Further described.

[0032] The console 24 includes a processor 41 (typically a general purpose computer) and appropriate front end and interface circuitry 38 including a patient interface unit (PIU) 52 for (a) receiving analog ECG signals and digital ECG signals from the dongle 50 and non-ECG signals (such as position signals) from the sensing electrodes 48 of the catheter 21, and (b) selecting the catheter electrode from which to apply pacing to the tissue.

[0033] The electrodes 48 can include 256 or more sensing n electrodes. Each of the electrodes 48 is referred to as an "electrode 48#1, #2, #3... #n" disposed within or near the heart. To this end, the processor 41 is connected to the sensing electrodes 48 via wires extending within the shaft 22. The interface circuitry 38 is further configured to receive ECG signals from the body surface electrodes 49 and non-ECG signals. Typically, the electrodes 49 are attached to the skin around the chest and legs of the patient 28. The processor 41 is connected to the electrodes 49 by wires extending through the cable 39 to receive signals from the electrodes 49.

[0034] The processor 41 is typically programmed in software to perform the functions described herein. For example, the software can be downloaded to the processor in electronic form over a network, or alternatively or additionally the software can be provided and / or stored on non-transitory tangible media, such as magnetic, optical, or electronic memory. Specifically, the processor 41 runs a special purpose algorithm included in the software as disclosed herein that enables the processor 41 to perform the steps disclosed by the present invention, as further described below. Figure 3

[0035] Distributed cardiac pacing system

[0036] Figure 2 Block diagram of a cardiac pacing and electrophysiology sensing device for the system 20 of the Figure 1 exemplary embodiment of the present invention.

[0037] As shown, the catheter 21 of the system 20 is connected to the dongle 50 with the distal end of the catheter 21 inserted into the heart 26 to sense electrophysiology signals and / or pace cardiac tissue. All of the electrodes 48 of the catheter 21 can acquire or apply analog signals, however there are not enough available (e.g., existing) analog wires 60 in the system 20 to connect all of the electrodes 48 to the PIU 52 of the console 24.

[0038] As Figure 2 ​Further shown, the dongle 50 routes the legacy analog line 60 to the PIU 52 for use with the subset of electrodes 48 selected for analog connection. The dongle 50 further connects to the PIU 52 via an ADC within the dongle 50 using the digital line 70 for the PIU 52 to receive signals from the remaining digital connected subset of electrodes 48.

[0039] Two of the catheter electrodes 48 are selected for pacing. The two pacing electrodes can be selected by a user interface of the PIU 52 and the identity of the selected electrodes (e.g., run index) is communicated from the PIU 52 to the processor 41 of the console 24. If the two selected electrodes belong to the analog connected subset of electrodes 48, then these electrodes are already routed to the recording system 35 and the pacing unit 37 by the composite analog line 60-62-64. The PIU 52 is configured to be able to pace from the unit 37 via the composite analog line (i.e., using the series lines 60, 62, and 64) when commanded by the user. This configuration has been configured to command the relay 51 in the dongle 50 to switch to the selected pacing electrodes to use the composite line 60-62-64 to deliver the pacing signal to the heart 26.

[0040] However, if the two selected electrodes belong to the digital connected subset of electrodes 48, then the PIU 52 can only provide the identity of the electrodes to the processor 41. To pace via the selected electrodes, the user uses a dedicated composite line 74-100-110 from the pacing unit 37 to the dongle 50.

[0041] The analog pacing signal in line 74 is routed via the recording system 35 through the analog line 100 to the pacing detection circuit 55. The circuit 55 routes the signal via two dedicated lines 110 comprising two single wires. In addition, upon sensing the analog pacing signal, the circuit 55 triggers (120) the processor 41 via line 76 to send a command to the dongle 50 to switch the relay 51 to the physical input of the dongle 50 to line 110. In response, the dongle 50 switches the selected electrodes to deliver the pacing signal running in line 110 to the heart 26.

[0042] Figure 1 And Figure 2 The exemplary configuration shown is chosen for clarity of concept only. In alternative embodiments, the technology disclosed can use other suitable configurations, including other wiring schemes, different standalone interfaces and switching devices, and catheter types other than basket catheters.

[0043] Figure 3 To illustrate schematically the use of the exemplary embodiment of the application for using Figure 2A flowchart of a method of pacing a patient using the apparatus of the present application. The algorithm according to the exemplary embodiment of the present application performs the following process, which begins with an ECG recording step 80 in which the physician 30 uses the plurality of electrodes 48 of the catheter 21 to acquire intracardiac ECG signals within the heart 26, which are recorded by the recording system 35.

[0044] At a pacing set step 82, the physician 30 or the algorithm selects two of the electrodes 48 to pace the heart 26. At a check step 84, the system responds according to whether the selected electrodes belong to the analog or digital subset of the electrodes.

[0045] If the selected electrodes are connected via analog lines (i.e., the selected electrodes belong to the analog subset of the electrodes), then at a pace step 86, the apparatus handles the selection using existing (e.g., conventional) hardware and programming.

[0046] On the other hand, if the selected electrodes are connected via digital lines, then at an electrode identification step 88, the PIU 52 of the system outputs the identity of the selected electrodes to the processor 41, and no further intervention.

[0047] Once pacing is initiated and it is known that the electrode identity is that of an electrode connected via digital lines, at an output pace signal step 90, the physician 30 or the algorithm operates the pacing unit 37 to output the pacing signal via the dedicated analog line 74.

[0048] At a pace signal detection step 92, the pace detection circuit 55 detects the pacing signal and responsively triggers the processor 41.

[0049] Once triggered by the pace detection circuit 55 (at step 94), at a switch step command 96, the processor 41 commands a switching component (such as including the relay 51 within the dongle 50) to switch the selected electrodes from the digital lines (70) to the dedicated analog pacing line (110).

[0050] At a pace application step 98, responsively, the switching component within the dongle 50 switches the selected electrodes according to the command to apply pacing.

[0051] Figure 3 The exemplary flowchart shown in FIG. 1 is chosen for conceptual clarity only. For example, the method disclosed in the present application can include additional steps such as verifying the contact of the selected electrodes with tissue before switching to pacing, and a step of switching the electrodes back to the digital lines at the end of pacing.

[0052] It should be understood that the above-described embodiments have been presented by way of example only, and that the application is not limited to the particulars cited above. Rather, the scope of the present application includes combinations and sub-combinations of the various features described above, as well as variations and modifications thereof, which will occur to those skilled in the art upon reading the above description, and which are not disclosed in the prior art. Documents incorporated by reference in the present patent application are to be considered an integral part of the application, except that to the extent any terms are defined in such incorporated documents in a manner conflicting with the definitions made explicit or implicit in the present application, only the definitions made explicit or implicit in the present application should be considered.

Claims

1. A device for cardiac pacing, the device comprising: A relay and a sampling unit configured to receive multiple electrocardiogram (ECG) signals sensed by corresponding electrodes in a patient's heart, digitize a first subset of the ECG signals, and forward a second subset of the undigitized ECG signals via an analog line; A pacing unit, the pacing unit being configured to output a pacing signal; A pacing detection circuit, configured to detect the pacing signal and output a trigger in response to the pacing signal; as well as Processor, the processor being configured to: Receive (i) the trigger and (ii) the identification of the electrode in the electrodes through which the pacing signal is to be applied; as well as In response to the identification that the electrode to which the pacing signal is to be applied is currently associated with a digitized ECG signal, the relay and sampling unit are instructed to switch the identified electrode to the analog line for transmitting the pacing signal.

2. The device of claim 1, further comprising a patient interface unit (PIU) configured to receive and store the identity identifier of the electrode to which the pacing signal is to be applied, and wherein the processor is configured to read the identity identifier from the PIU once triggered by the pacing detection circuitry.

3. The device of claim 2, wherein the relay and sampling unit are included in a dongle that connects the electrodes to the PIU.

4. The device of claim 1, wherein the pacing detection circuit is further configured to detect that the pacing signal has stopped and respond to trigger the processor, and wherein the processor is further configured to, once triggered, command the relay and the sampling unit to switch the selected electrode from the analog line to the digital line.

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