Implantable medical device, cardiac therapy system and method for operating an implantable medical device

Abstract

The invention relates to an implantable medical device (10), in particular leadless pacemaker, comprising a hermetic housing (12), a pacing electrode (14) disposed on a distal portion of the housing (12), an electronics package (16) disposed in the housing (12) configured to generate and deliver pacing output to the pacing electrode (14) and a fixation mechanism (18) arranged on the distal portion of the housing (12) adapted to engage with heart tissue to anchor the implantable medical device (10), wherein the implantable medical device (10) comprises a preset initial operation mode usable prior to and during implantation, wherein in said initial operation mode, the implantable medical device (10) is configured to disable pacing output and to run at least one electrical characterization test. The invention further relates to a cardiac therapy system and a computer-implemented method for operating an implantable medical device (10).

Description

[0001] Implantable medical device, cardiac therapy system and method for operating an implantable medical device

[0002] The invention relates to an implantable medical device. Furthermore, the invention relates to a cardiac therapy system and a method for operating an implantable medical device.

[0003] With traditional leaded IPGs, clinicians commonly preconfigure the therapy output and independently position the leads used to administer therapy from the IPG. In positioning the leads, the clinician performs anchor site electrical evaluations by typically driving paced output or assessing sensed activity from the heart by connecting to the lead, typically via alligator clip attachments, to a special analyzer. If the lead is positioned / anchored in a location where the electrical characteristics are sub-optimal for administering sustained therapies, the clinician can detach the analyzer or disable its output and reposition the lead, often by means of a stylet, until a suitable anchor site has been determined. Only after such a site has been found the clinician then physically attaches the IPG which can proceed to administer therapy either instantaneously or subject to the outcome of an auto-implant detection procedure. As noted, such routines are solely relevant and applicable to traditional leaded IPG systems.

[0004] Unlike traditional pocket-based leaded implantable pulse generators, leadless pacemaker implantation, either de novo or as a replacement device at change-out, does not involve any clinician-administered processes associated with the physical connection of the device’s therapeutic pace output to electrical conductors, e.g., leads, capable of transporting such output to the patient’s cardiac anatomy. As such, the evaluation of anchor site quality is inherently coupled to electrical characterizations enabled by the device itself. The configuration of the pacemaker’s therapy output is thus more readily capable of impacting the ability to evaluate the electrical characteristics of any candidate anchoring site within the patient’s cardiac anatomy and thus introduces uniquely confounding circumstances that merit special management.

[0005] In leadless pacemakers, solutions for needing to avoid sustained therapeutic output while simultaneously enabling the temporary administration of electrical tests requisite for the electrical characterization of a potential multitude of device anchor site locations complete with reporting such temporary conditions to the user are only known to exist through the incorporation of user-programmable therapy OFF states. Coupled with an apparently further absence of known reporting mechanisms for these OFF-state conditions, undesirable risks are introduced.

[0006] Of critical interest is therefore the ability to electrically survey the anchor site quality at any location of interest within the heart and support the ability to reposition the implant to any other location of interest without such transitions encountering complications that stem from the implant’s capacity to render bradycardia remediation therapy.

[0007] It is therefore an object of the present invention to provide an implantable medical device offering an improved functionality for supporting an implantation procedure.

[0008] The object is solved by an implantable medical device having the features of claim 1. Furthermore, the object is solved by a cardiac therapy system having the features of claim 9. Moreover, the object is solved by a computer-implemented method for operating an implantable medical device having the features of claim 15.

[0009] Further developments and advantageous embodiments are defined in the dependent claims.

[0010] The present invention provides an implantable medical device, in particular a leadless pacemaker, comprising a hermetic housing, a pacing electrode disposed on a distal portion of the housing, an electronics package disposed in the housing configured to generate and deliver pacing output to the pacing electrode, and a fixation mechanism arranged on the distal portion of the housing adapted to engage with heart tissue to anchor the implantable medical device, wherein the implantable medical device comprises a preset initial operation mode usable prior to and during implantation, wherein in said initial operation mode, the implantable medical device is configured to disable pacing output and to run at least one electrical characterization test.

[0011] Furthermore, the present invention provides a cardiac therapy system comprising an implantable medical device according to the present invention and a programming device configured to exchange data with the implantable medical device.

[0012] In addition, the present invention provides a computer-implemented method for operating an implantable medical device. The method comprises setting the implantable medical device in an initial operation mode usable prior to and during implantation, disabling pacing output in the initial operation mode, and running at least one electrical characterization test in the initial operation mode.

[0013] An idea of the present invention is to fill the need to support the targeted execution of electrical characterization tests when surveying candidate implantation sites while avoiding the delivery of any sort of sustained therapy output from the implant until a suitable implantation site has been determined. Supporting such procedures while simultaneously informing the clinician managing the process of any affiliate changes in the pace output conditions is key.

[0014] The present invention thus improves upon the robustness of support in leadless pacemaker systems in the selective application of support for running follow-up tests while the device nominally resides within a low-power “shelf’ condition and only transitioning such devices to a fully operational ON state once a reliable / suitable implantation site has been determined.

[0015] This approach avoids conditions where a therapy output from the implant could stimulate a cardiac contraction while the implant is being mechanically anchored into heart tissue. Supporting this process in ways where the clinician is informed of the implant’ s pacing status throughout add to the robustness, convenience, and safety of such routines in clinically meaningful ways. The invention thus enables the evaluation of a potential multitude of leadless pacemaker anchoring locations within the cardiac anatomy without forcing the user to execute a complex series of procedural steps.

[0016] The invention furthermore reduces the risk for unintentionally sending the patient away from the clinic without therapy support following implantation procedures.

[0017] According to an embodiment of the present invention, the initial operation mode is a low- power mode in which the implantable medical device consumes a minimum amount of power, since higher-load functions as pacing the heart and sensing heart signals are mainly disabled.

[0018] According to an embodiment of the invention, the at least one electrical characterization test comprises an electrode impedance test, a pacing capture threshold test and / or a sense amplitude test. Said tests thus provide an effective tool in determining a suitable anchoring site for the implantable medical device.

[0019] According to a further embodiment of the invention, in said initial operation mode, the implantable medical device is configured to respond to commanded input from a programming device such that the at least one electrical characterization test is executable during an anchor site evaluation of the implantable medical device within the heart. Thus, an optimal anchor site for the implantable medical device can be determined before therapy output of the implantable medical device is enabled.

[0020] According to a further embodiment of the invention, the implantable medical device, when in said initial operation mode, is configured to respond to commanded inputs from the programming device that temporarily forces a transition away from the initial operation mode. Thus, the implantable medical device can temporarily be operated in a mode different from the initial operation mode.

[0021] According to a further embodiment of the invention, in said initial operation mode, the implantable medical device is configured to temporarily enable an administration of pacing output and / or sensing support for monitoring intrinsic cardiac events. This supports the execution of the various electrical characterization tests.

[0022] According to a further embodiment, in said initial operation mode, the implant may be configured to administer said electrical characterization tests by executing a temporary program. A temporary program is one that can executes while active programmer communication is in effect, but if there is ever a disruption to the communication (e.g. a wand lift) the implant will revert back to its permanent initial non-therapeutic operation mode.

[0023] According to a further embodiment of the invention, the implantable medical device is configured to report an implant stimulus condition to a programming device. The programming device is thus capable of informing a medical practitioner on said implant stimulus condition.

[0024] In particular, the implantable medical device may be configured to report to the programming device that the implantable medical device is set in the initial operation mode. Moreover, the reporting may include that the implantable medical device has disabled pacing output and / or sensing support. This constitutes a warning mechanism that helps make the user aware that the implantable medical device is not programmed to deliver therapy and thus helps to protect the patient.

[0025] In a further embodiment, the implantable medical device may report the stimulus condition or the setting in the initial operation mode by sending a communication message to the programming device. The communication message may include an information on a stimulus condition of the implantable medical device or a setting of the implantable medical device in the initial operation mode. The information may be encoded in a communication protocol of the communication message. In a further embodiment, the communication message may be sent to the programming device in response to an interrogation of the programming device. Moreover, the information on the stimulus condition and / or on an operation mode of the implantable medical device may be connected to identification information of the implantable medical device for identifying the implantable medical device within a certain operation range.

[0026] According to a further embodiment of the invention, in said initial operation mode, the implantable medical device is configured to disable both the pacing output and the sensing support. Thus, a safe anchor site determination can be performed without the risk of involuntarily enabling pacing output and / or sensing support.

[0027] According to a further embodiment of the invention, in said initial operation mode, the implantable medical device is configured to disable pacing output and sensing support while recording of IEGM signals and forwarding IEGM signals at least in parts to the programming device is enabled. Thus, a safe anchor site determination can be performed at low energy consumption.

[0028] According to a further embodiment of the invention, the implantable medical device is configured to provision pacing output while executing commanded pacing capture threshold tests; enable support for executing impedance tests; and enable sense amplitude test execution wherein the implantable medical device is configured to monitor intrinsic cardiac events and determine the amplitudes of such events by assessing the assocated IEGM data. The implantable medical device is thus advantageously able to temporarily provision pacing output when needed to perform said electrical characterization tests.

[0029] According to a further embodiment, the implantable medical device is configured to carry out at least one of the following operations: provision pacing output while executing commanded pacing capture threshold tests and / or impedance tests, and monitoring intrinsic cardiac events and / or acquire metrics on such events via, in particular lEGM-based, data acquisition while executing commanded sense amplitude tests.

[0030] According to a further embodiment of the invention, a user interface of the programming device provides a pacing status indication via a visual and / or acoustic identifier. The implantable medical device thus provisions a real-time awareness of any conditions where pacing output is enabled or disabled. According to a further embodiment of the invention, the implantable medical device is configured to report the implant stimulus condition to the user through the use of the pacing status indicator of the programming device. The pacing status indicator thus provides a convenient notification to the user of the programming device.

[0031] According to a further embodiment of the invention, the implantable medical device and / or the user interface of the programming device is configured to generate a warning message prompting the user to confirm that the implantable medical device is anchored within the ventricle and that testing is complete before executing a therapeutic program. Thus, an additional layer of safety is provided that prevents sustained, permanent pacing therapy output to be turned on before a suitable anchoring site for the implantable medical device has been determined. The cardiac therapy system thus incorporates a warning / notification within the programming device GUI that asks the user to confirm that a viable implantation site has been located before transitioning the implant away from “shelf’.

[0032] According to a further embodiment of the invention, the implantable medical device and / or the user interface of the programming device is configured to generate a further warning message if an attempt to terminate a programming device session is made while the implantable medical device is in the initial mode prompting the user to program a therapeutic program.

[0033] The incorporation of a warning / notification within the programming device GUI thus makes users aware that closing active programming device communication sessions when implants remain in a “shelf’ condition are apt to leave the patient in a therapeutically unsupported condition.

[0034] According to a further embodiment of the invention, the user interface of the programming device comprises a safety measure configured to disallow the implantable medical device to be permanently programmed into a non-therapeutic state. The herein described features of the implantable medical device are also disclosed for the cardiac therapy system, the computer-implemented method for operating an implantable medical device and vice versa.

[0035] For a more complete understanding of the present invention and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings. The invention is explained in more detail below using exemplary embodiments, which are specified in the schematic figures of the drawings, in which:

[0036] Fig. 1 shows a diagram of an implantable medical device according to a preferred embodiment of the invention;

[0037] Fig. 2 shows a diagram of a cardiac therapy system according to the preferred embodiment of the invention; and

[0038] Fig. 3 shows a flowchart of a computer-implemented method for operating the implantable medical device according to the preferred embodiment of the invention.

[0039] The implantable medical device 10 shown in Fig. 1 comprises a pacing electrode 14 disposed on a distal portion of the housing 12 and an electronics package 16 disposed in the housing 12 configured to generate and deliver pacing output to the pacing electrode 14.

[0040] Furthermore, the implantable medical device 10 comprises a fixation mechanism 18 arranged on the distal portion of the housing 12 adapted to engage with heart tissue to anchor the implantable medical device 10, wherein the implantable medical device 10 is operable in a preset initial operation mode usable prior to and during implantation, wherein in said initial operation mode, the implantable medical device 10 is configured to disable pacing output and to run at least one electrical characterization test.

[0041] The implantable medical device 10, in particular the leadless pacemaker thus provides said initial operation mode, i.e. a low-power “shelf’ condition. This low-power “shelf’ condition represents a factory-set shipped state. When resident in this condition, the implant is configured to an OOO mode where both the pacing and the sensing support is disabled.

[0042] Despite being configured to a mode that, in nominal form, denies the administration of both therapy and diagnostic support, the device is further made capable of responding to commanded inputs from a programming device 22 that can temporarily force transitions away from this 000 mode.

[0043] The at least one electrical characterization test comprises an electrode impedance test, a pacing capture threshold test and / or a sense amplitude test. Furthermore, in said initial operation mode, the implantable medical device 10 is configured to respond to commanded input from a programming device 22 such that the at least one electrical characterization test is executable during an anchor site evaluation of the implantable medical device 10 within the heart.

[0044] The implantable medical device 10, when in said initial operation mode, is configured to respond to commanded inputs from the programming device 22 that temporarily forces a transition away from the initial operation mode.

[0045] While executing commanded pacing capture threshold tests or impedance tests, the implant can provision pacing output and while executing commanded sense amplitude tests, the implant can monitor intrinsic cardiac events and acquire metrics on such events via IEGM- based data acquisition.

[0046] Moreover, in said initial operation mode, the implantable medical device 10 is configured to temporarily enable an administration of pacing output and / or sensing support for monitoring intrinsic cardiac events.

[0047] The implantable medical device 10 is configured to report an implant stimulus condition to the programming device 22. In said initial operation mode, the implantable medical device 10 is configured to nominally disable both the pacing output and the sensing support. In addition, the implantable medical device 10 is configured to provision pacing output while executing commanded pacing capture threshold tests or impedance tests, and while executing commanded sense amplitude tests the implantable medical device 10 is configured to monitor intrinsic cardiac events and acquire metrics on such events via, in particular lEGM-based, data acquisition.

[0048] Fig. 2 shows a diagram of a cardiac therapy system according to the preferred embodiment of the invention. The cardiac therapy system comprises an implantable medical device 10 according to the present invention. Furthermore, the cardiac therapy system comprises a programming device 22 configured to exchange data with the implantable medical device 10.

[0049] A user interface of the programming device 22 provides a pacing status indication via a visual and / or acoustic identifier. Moreover, the implantable medical device 10 is configured to report the implant stimulus condition to the programming device 22 through the use of the pacing status indicator 24.

[0050] In concert with the “shelf’ state relevant to shipping and implantation procedures, a pacing status indicator 24 is incorporated within the programmer GUI for improved engagement with such implants. Since the default condition of a “shelf’ state embodies an OOO mode, the pacing status indicator 24 nominally presents a display of the absence of baseline therapy output from the device unless a commanded follow-up test during this “shelf’ OOO state temporarily instates pace output from the implant.

[0051] Subject to the execution of any of the aforementioned commanded follow-up tests that render pacing output, the pacing status indicator 24 toggles to a condition where the display of an absence of therapy output temporarily disappears.

[0052] As additional elements in the design framework for optimized implantation, the suite of user- programmable modes offered by the device are restricted to offerings that all administer some form of pacing output. It is thus not possible for the user to install a permanent program into the leadless pacemaker that fails to deliver therapy after the device has been programmed out of the “shelf’ condition in which it was shipped. The implantable medical device 10 and / or the user interface of the programming device 22 is further configured to generate a warning message prompting a user to confirm that the implantable medical device 10 is anchored within the ventricle and that testing is complete before executing the permanent program. It furthermore offers support for requesting that permanent therapy is instated before terminating the communication engagements with the implant associated with the device’s implantation process (i.e., if an attempt to terminate a session with the programming device 22 is made while the implantable medical device 10 is in the initial mode, prompting the user to program a viable therapeutic permanent program). In addition, the user interface of the programming device 22 comprises a safety measure configured to disallow the implantable medical device 10 to be permanently programmed into a non-therapeutic state once the device has been transitioned away from a non- therapeutic “shelf’ condition.

[0053] Paired with a therapeutically-enabled suite of mode selections, any user attempts to program a device residing in “shelf’ will be accompanied by a notification / warning making users aware that proceeding will effectively deny user access to any subsequent return to the OOO- based “shelf’ condition. The GUI interfacing is thus structured to encourage users to only exit the “shelf’ condition when a known, robust, clinically-relevant anchoring site has been found prior.

[0054] By only offering permanent program support for mode selections that provision paced output, users are restricted from accidentally programming the device into a non-therapeutic condition barring the use of an OOO mode in MRI-related mode applications or the permanent device disablement afforded to nominally support device decommissioning at the end of service.

[0055] The warnings or notifications by the therapy system preferably appear in the following order: 1) Attempts to program the device away from "shelf1give a warning that doing so is a "oneway" routine that will instate pacing henceforth and therefore should only occur once a viable anchor site has been found. 2) In-GUI notifications of the enabled / disabled status of pacing are rendered. These warnings are most important when the device is in the initial shelf state and the user is temporarily administering pace output through commanded follow-up tests.

[0056] 3) If the user attempts to end a programmer session with the implant and the implant resides in "shelf the user is notified that closing the session would problematically leave the patient in a condition that lacks therapeutic output.

[0057] 4) Once the user has programmed the device out of "shelf1the GUI or system is structured such that there is no capacity to program the device back into "shelf and there is no OOO permanent pacing mode.

[0058] In the MRI context, the 000 condition is of limited duration due to a built-in expiration for any programmed MRI-related modes while permanent disablement involves a deliberate sequence of notification-afflicted steps as protections against unintended use. These measures heavily bias user engagement away from circumstances where the patient might be left unsupported therapeutically after follow-up.

[0059] Fig. 3 shows a flowchart of a computer-implemented method for operating the implantable medical device 10 according to the preferred embodiment of the invention.

[0060] The method comprises setting SI the implantable medical device 10 in an initial operation mode usable prior to and during implantation. Furthermore, the method comprises disabling S2 pacing output in the initial operation mode, and running S3 at least one electrical characterization test in the initial operation mode.

[0061] In a case where an implantable medical device is implanted as a first device (in contrast to a replacement of an implantable medical device), there is a crucial need to avoid pacing output while the clinician searches for an ideal implant anchoring location (by virtue of the results gathered from the electrical characterization tests executed in the low-power initial operation mode). Subsequently, it is very essential to not forget to enable active pace output therapy from the implant before sending the patient home from the clinic. This need is especially acute in an implantation case compared to a device replacement case because in the replacement case, there is, at least, a second implant present in the patient that can provide some form of bradycardia remediation in the event that the clinician missed to activate the replacement implant. The pacing status indicator in the programming device aims at solving this problem, since it provides a capability of the programming device to conspiciously indicate that the device is not delivering therapeutic support.

[0062] Furthermore, the programmer device may be configured to output a warning message, by way of dialogue pop-up boxes on a GUI of the programming device which work to caution against unintentionally leaving the patient in the non-therapeutic initial operation mode if a user attempts to close the GUI without first programing a permanent therapy mode into the implant.

[0063] Furthermore, the programmer device may be configured to output a notice to encourage that the implant is anchored reliably within heart tissue prior to running any electrical characterization test while the implant is set in the initial operation mode. This might decrease the risk of stimulating the heart and causing the heart tissue to contract away from the implant challenging the ability to obtain meaningful electrical metrics relevant to the quality of the anchor site.

[0064] Furthermore, the programming device may be configured to recognize an operation mode of the implant, in particular a setting of an initial operation mode, within a response message of the implant responding to an interrogation command of the programming device for identifying potential in-range implants. The present operation mode of an identified in-range implant may be stored in a communication protocol of the implant. This technique of recognizing an operation mode of a potential in-range implant is different to a common procedure in a replacement case which focusses on a post-interrogation engagement with the replacement implant. There the device to be replaced is first engaged with by the programming device but the replacement device is made accessible after the interrogation of the device to be replaced by reopening the capacity to discover and search for the replacement device. Reference Signs

[0065] 1 system

[0066] 10 implantable medical device 12 housing

[0067] 14 pacing electrode

[0068] 16 electronics package

[0069] 18 fixation mechanism

[0070] 22 programming device 24 pacing status indicator

[0071] SI -S3 method steps

Claims

Claims1. Implantable medical device (10), in particular leadless pacemaker, comprising: a hermetic housing (12); a pacing electrode (14) disposed on a distal portion of the housing (12); an electronics package (16) disposed in the housing (12) configured to generate and deliver pacing output to the pacing electrode (14); and a fixation mechanism (18) arranged on the distal portion of the housing (12) adapted to engage with heart tissue to anchor the implantable medical device (10), wherein the implantable medical device (10) comprises a preset initial operation mode usable prior to and during implantation, wherein in said initial operation mode, the implantable medical device (10) is configured to disable pacing output and to run at least one electrical characterization test.

2. Implantable medical device (10) of claim 1, wherein the at least one electrical characterization test comprises an electrode impedance test, a pacing capture threshold test and / or a sense amplitude test.

3. Implantable medical device (10) of claim 1 or 2, wherein in said initial operation mode, the implantable medical device (10) is configured to respond to commanded input from a programming device (22) such that the at least one electrical characterization test is executable during an anchor site evaluation of the implantable medical device (10) within the heart.

4. Implantable medical device (10) of claim 3, wherein the implantable medical device (10), when in said initial operation mode, is configured to respond to commanded inputs from the programming device (22) that temporarily forces a transition away from the initial operation mode.

5. Implantable medical device (10) of any one of the preceding claims, wherein in said initial operation mode, the implantable medical device (10) is configured totemporarily enable an administration of pacing output and / or sensing support for monitoring intrinsic cardiac events.

6. Implantable medical device (10) of any one of the preceding claims, wherein the implantable medical device (10) is configured to report an implant stimulus condition to a programming device (22).

7. Implantable medical device (10) of any one of the preceding claims, wherein in said initial operation mode, the implantable medical device (10) is configured to disable both the pacing output and the sensing support.

8. Implantable medical device (10) of any one of the preceding claims, wherein the implantable medical device (10) is configured to carry out at least one of the following operations: provision pacing output while executing commanded pacing capture threshold tests or impedance tests, and monitoring intrinsic cardiac events and / or acquire metrics on such events via, in particular lEGM-based, data acquisition while executing commanded sense amplitude tests.

9. Cardiac therapy system comprising: an implantable medical device (10) of any one of claims 1 to 8; and a programming device (22) configured to exchange data with the implantable medical device (10).

10. Cardiac therapy system of claim 9, wherein a user interface of the programming device (22) provides a pacing status indication via a visual and / or acoustic identifier.

11. Cardiac therapy system of claim 10, wherein the implantable medical device (10) is configured to report the implant stimulus condition to the programming device (22) through the use of the pacing status indicator (24).

12. Cardiac therapy system of claim 10 or 11, wherein the implantable medical device (10) and / or the user interface of the programming device (22) is configured to generate ofa warning message prompting a user to confirm that the implantable medical device (10) is anchored within the ventricle and that testing is complete before executing a therapeutic program.

13. Cardiac therapy system of any one of claims 10 to 12, wherein the user interface of the programming device (22) comprises a safety measure configured to disallow the implantable medical device (10) to be permanently programmed into a non-therapeutic state.

14. Cardiac therapy system of any one of claims 10 to 13, wherein the implantable medical device (10) and / or the user interface of the programming device (22) is configured to generate a further warning message if an attempt to terminate a programming device (22) session is made while the implantable medical device (10) is in the initial operation mode prompting the user to program a therapeutic program.

15. Computer-implemented method for operating an implantable medical device (10), comprising the steps of setting (SI) the implantable medical device (10) in an initial operation modeusable prior to and during implantation; disabling (S2) pacing output in the initial operation mode;and running (S3) at least one electrical characterization test in the initial operation mode.

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