Determination of lower limit of pacing rate

Abstract

The lower pacing rate limit is used by the pacing device to initiate pacing in response to the patient's intrinsic rate being less than the lower pacing rate limit. Exemplary systems, devices, and methods may obtain rate modification information related to a patient, such as physical characteristics, diagnostic parameters, pathology, device characteristics of pacing devices implanted in the patient, and patient reporting information. The rate modification information may be used to determine a lower pacing rate limit based on the rate modification information.

Description

[0001] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 336,783, filed on April 29, 2022, entitled “Determination of Lower Pacing Rate Limit,” which is incorporated herein by reference in its entirety.

[0002] The present disclosure generally relates to determining a lower limit for a pacing rate used in a pacing device.

[0003] A pacing device, such as an implantable medical device (IMD), may utilize a pacing rate lower limit to determine when to initiate pacing. For example, the IMD may trigger or initiate the delivery of pacing in response to a patient's intrinsic heart rate being less than the pacing rate lower limit. In other words, when the patient's intrinsic heart rate moves below the pacing lower limit, the IMD may begin delivering pacing at the pacing lower limit. The pacing rate lower limit of the pacing device is programmed during the initial configuration of the pacing device after implantation, and typically the pacing rate lower limit does not change after the initial programming. Additionally, during the initial configuration, the pacing rate lower limit is also typically not changed from a default rate, which is typically 60 beats per minute. Furthermore, the selection of the pacing rate lower limit, for example by a physician, may not be guided by factors or evidence.

[0004] Additionally, various cardiac pathologies may provide insight into the optimal or more therapeutic lower limit of pacing rate. For example, patients with systolic dysfunction may benefit from lower rate pacing compared with patients with diastolic dysfunction or heart failure with preserved ejection fraction (HFpEF). Human clinical evidence shows that an elevated lower limit of pacing rate is promising in patients with HFpEF. Summary of the invention

[0005] The technology disclosed herein generally relates to determining or generating a lower limit of a pacing rate used in a pacing device. The determination or generation may be based on one or more different rate modification information. For example, the rate modification information may include a patient's physical characteristics, such as height, gender, age, body mass index (BMI), body surface area, physical fitness level, and activity level. In addition, for example, the rate modification information may include a patient's diagnostic parameters, such as ventricular contractility, ventricular stiffness, pulse transit time, resting heart rate, nocturnal heart rate, arrhythmia burden, target pacing burden, heart rate recovery, impedance, fluid overload, respiratory rate, maximum heart rate, ejection fraction, left ventricular pressure, comorbidities, systemic blood pressure, pulmonary artery pressure, blood oxygen, and the presence or concentration of serum biomarkers. In addition, for example, the rate modification information may include a patient's pathology, such as diastolic dysfunction / heart failure with preserved ejection fraction, systolic dysfunction, chronotropic insufficiency, and worsening heart failure. Further, for example, the rate modification information may include a pacing device configuration, such as pacing electrode location and pacing therapy type. Additionally, further rate modification information may be provided by a user such as the patient themselves. Patients may provide input or preferences based on their own objective and subjective observations.

[0006] One or more such heart rate modification information may be used by the exemplary systems, methods, and devices described herein to determine (e.g., generate, calculate, etc.) a pacing heart rate lower limit. In one or more embodiments, a physician may utilize or use an exemplary system that determines a pacing rate lower limit. Such exemplary system may obtain or acquire rate modification information from various sources, including user input dialogs on a local system used by a physician or technician, local or remote computing devices (e.g., electronic medical record systems), data measured or monitored by one or more medical devices including a pacing device, user input dialogs on a mobile computing device used by a patient, and the like. The exemplary system may then utilize such rate modification information to determine a pacing rate lower limit for the patient. Additionally, in one or more embodiments, after implantation, the pacing device itself may measure or monitor rate modification information from the patient and modify or change the pacing rate lower limit based on the measured or monitored rate modification information.

[0007] In addition, the physician may provide input or preferences based on their understanding of the patient and the patient's condition, which may be used in conjunction with the rate modification information. For example, the physician may provide a lower boundary and an upper boundary. When the exemplary systems, devices, methods, and processes determine or generate a pacing rate lower limit, the upper boundary and lower boundary input by the physician may be used to ensure that the pacing rate lower limit is neither less than the lower boundary nor greater than the upper boundary. In addition, the physician may provide a desired pacing percentage, which the IMD may use to increase the pacing rate lower limit if the patient exceeds the desired pacing percentage during therapy. For example, if the pacing rate lower limit is set to 70, 95% of the heartbeats are paced, and the desired pacing percentage input by the physician is 90%, the pacing rate lower limit may be increased (e.g., incrementally) until the percentage of heartbeats that are paced is equal to or less than the desired pacing percentage.

[0008] Exemplary systems, devices, methods, and processes may be described as assisting a clinician in determining an optimal lower pacing rate limit, which may increase the likelihood that a device lower pacing rate limit is optimally programmed. Additionally, exemplary methods and processes may be described as features incorporated into exemplary device programming instruments and systems to help facilitate programming of patient-specific lower pacing rate limits. Furthermore, exemplary techniques may also be described as tools or algorithms for optimizing programmed lower pacing rate limits or lower rate settings on a device having cardiac pacing capabilities.

[0009] Exemplary methods and processes may be incorporated into a programming instrument or a networked system and may be described as calculating a pacing rate lower limit based on various data sources, including manually entered data or data from a connected database. In addition, exemplary systems, devices, methods, and processes may be described as utilizing device diagnostic data and patient self-reported data to adjust the pacing rate lower limit over time to optimize clinical outcomes and / or reduce symptoms. In addition, exemplary systems, devices, methods, and processes may be described as assisting in selecting an optimal pacing rate lower limit, thereby reducing the clinical burden in identifying programming best practices. An exemplary embodiment may be described as an application on a programming instrument or a networked system that calculates a pacing rate lower limit based on patient-specific rate modification information such as patient height, sex, age, pathology, lead position, and desired activity performance. The rate modification information may be manually entered, for example, during initial programming on a programmer instrument, and / or may be imported from other connected data sources / registries (e.g., electronic medical records) to calculate the pacing rate lower limit. Another exemplary embodiment may be an IMD that refines a programmed pacing heart rate lower limit based on heart rate modification information that is itself monitored or measured over time using the IMD or other connected patient monitoring device. For example, the pacing rate lower limit may be increased or decreased based on pre-specified targets for one or more diagnostic parameters, such as target pacing burden, arrhythmia burden, nocturnal heart rate, activity, etc. Another exemplary embodiment may utilize patient reported information obtained from a mobile computing device. For example, the embodiment may adjust the pacing rate lower limit within a pre-specified range for patient symptoms. Patient reported information (e.g., patient reported symptoms) may be provided using a patient mobile application on a mobile computing device (such as a cellular smart phone). The mobile computing device and / or an IMD communicatively coupled thereto may adjust the pacing rate lower limit in an attempt to minimize patient reported symptoms, such as energy level, peripheral edema, etc.

[0010] In one example, aspects of the present disclosure relate to determining a pacing rate lower limit, wherein the pacing rate lower limit is used by a pacing device to initiate pacing in response to an intrinsic rate of a patient being less than the pacing rate lower limit. An exemplary method may include obtaining, with the pacing device, rate modification information including at least one physical characteristic of the patient, and determining a pacing rate lower limit for the pacing device based on the obtained rate modification information.

[0011] An exemplary system may include a computing device including one or more processors. The computing device may be configured to obtain, with a pacing device, rate modification information including at least one physical characteristic of a patient, and determine a pacing rate lower limit for the pacing device based on the obtained rate modification information,

[0012] An exemplary implantable medical device may include one or more electrodes for delivering cardiac pacing therapy to a patient's heart and sensing electrical activity from the patient's heart, and a computing device operably coupled to the one or more electrodes and including one or more processors. The computing device of the implantable medical device may be configured to monitor the patient's intrinsic heart rate using the one or more electrodes, deliver pacing therapy to the patient's heart in response to the patient's intrinsic rate being less than a pacing rate lower limit, obtain rate modification information including at least one physical characteristic of the patient using a pacing device, and determine a pacing rate lower limit for the pacing device based on the obtained rate modification information.

[0013] The details of one or more aspects of the present disclosure are set forth in the following drawings and description. Other features, objectives, and advantages of the techniques described in the present disclosure will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a diagram of an illustrative system including an IMD and a programmer.

[0015] Figure 2 yes Figure 1 Graph of an exemplary IMD.

[0016] Figure 3A yes Figure 1 to Figure 2 Block diagram of the IMD.

[0017] Figure 3B is Figure 1 to Figure 2 Another block diagram of the IMD circuit and associated leads employed in an IMD.

[0018] Figure 4 yes Figure 1 Diagram of an illustrative programmer for a system.

[0019] Figure 5 Yes Figure 1 FIG. 1 is a diagram of an illustrative system of an IMD and a programmer and additional devices coupled thereto via a network.

[0020] Figure 6 An exemplary method of determining a lower limit on the pacing rate is to use, for example, Figures 1 to 5 systems and devices.

[0021] Figure 7 is an exemplary graphical user interface for determining a pacing rate lower limit, such as using Figures 1 to 6 Systems, devices and methods. DETAILED DESCRIPTION

[0022] The technology disclosed herein generally relates to the determination of a pacing rate lower limit for use in a pacing device. A pacing device, such as an implantable medical device (IMD), may utilize a pacing rate lower limit to determine when to initiate pacing. In particular, the pacing device may simulate or deliver pacing therapy in response to a patient's intrinsic rate being less than the pacing rate lower limit. In other words, the pacing rate lower limit may be described as the rate at which the pacing device would pace the patient's heart in the absence of intrinsic cardiac activity. Figures 1 to 7 Exemplary systems, devices, methods, and processes for determining and / or adjusting a lower limit on a pacing rate are described.

[0023] Figure 1 1 is a conceptual diagram of an exemplary therapy system 10 that can be used to deliver pacing therapy (such as adaptive cardiac pacing therapy, cardiac resynchronization therapy, etc.) to a patient 14. Although the patient 14 is shown as a human, the patient 14 can also be various other types of animals. The therapy system 10 may include an implantable medical device 16 (IMD) that can be coupled to leads 18, 20, 22 and a programmer 24. The IMD 16 can be, for example, an implantable pacemaker, cardioverter, and / or defibrillator that delivers or provides electrical signals (e.g., pacing, etc.) to the heart 12 of the patient 14 via electrodes coupled to one or more of the leads 18, 20, 22 and / or senses electrical signals from the heart of the patient.

[0024] Leads 18, 20, 22 extend into heart 12 of patient 14 to sense electrical activity of heart 12 and / or deliver electrical stimulation to heart 12. Figure 1 In the example shown, the right ventricular (RV) lead 18 extends through one or more veins (not shown), the superior vena cava (not shown), and the right atrium 26, and into the right ventricle 28. The right atrial (RA) lead 22 extends through one or more veins and the vena cava, and into the right atrium 26 of the heart 12.

[0025] IMD 16 may sense electrical signals associated with depolarization and repolarization of heart 12, etc., via electrodes coupled to at least one of leads 18, 20, 22. In some examples, IMD 16 provides pacing therapy (e.g., pacing pulses) to heart 12 based on the electrical signals sensed within heart 12. IMD 16 may be operable to adjust one or more parameters associated with pacing therapy, such as pacing rate, RR interval, AV delay, and other various timings, pulse width, amplitude, voltage, burst length, etc. Further, IMD 16 may be operable to deliver pacing therapy using various electrode configurations, which may be unipolar, bipolar, quadripolar, or further multipolar. Thus, a multipolar lead system may provide or supply multiple electrical vectors to pace from. The pacing vector may include at least one cathode and at least one anode, the at least one cathode may be at least one electrode located on at least one lead, and the at least one anode may be at least one electrode located on at least one lead (e.g., the same lead or a different lead) and / or on a housing or can of the IMD or electrode device. Although the improvement in cardiac function as a result of pacing therapy may depend primarily on the cathode, electrical parameters such as impedance, pacing threshold voltage, current consumption, life span, etc. may be more dependent on the pacing vector, which includes both the cathode and the anode. The IMD 16 may also provide defibrillation therapy and / or cardioversion therapy via electrodes located on at least one of the leads 18, 20, 22. Further, the IMD 16 may detect arrhythmias of the heart 12, such as fibrillation of the ventricles 28, 32, and perform defibrillation therapy on the heart 12 in the form of electrical pulses. In some examples, the IMD 16 may be programmed to deliver a course of therapy, for example, pulses with increasing energy levels, until the fibrillation of the heart 12 ceases.

[0026] In some examples, programmer 24 may be a mobile computing device or a computer workstation. Programmer 24 may include a user interface that receives input from a user. The user interface may include, for example, a keypad and a display, which may be, for example, a liquid crystal display (LCD) or a light emitting diode (LED) display. The keypad may take the form of an alphanumeric keypad or a reduced set of keys associated with specific functions. Programmer 24 may additionally or alternatively include a peripheral pointing device such as a mouse, via which a user may interact with the user interface. In some embodiments, the display of programmer 24 may include a touch screen display, and the user may interact with programmer 24 via the display.

[0027] A user, such as a physician, technician, patient, or other user, may interact with programmer 24 to communicate with IMD 16. For example, the user may interact with programmer 24 to retrieve physiological or diagnostic information from IMD 16. The user may also interact with programmer 24 to program IMD 16, e.g., to select values ​​for operating parameters of the IMD. For example, the user may interact with programmer 24 to determine a pacing rate lower limit for the patient based on the rate modification information and then configure or program IMD 16 with the pacing rate lower limit.

[0028] Additionally, for example, the user may use programmer 24 to retrieve information from IMD 16 regarding the rhythm of heart 12, trends therein over time, or episodes of tachyarrhythmias. As another example, the user may use programmer 24 to retrieve information from IMD 16 regarding other sensed physiological or diagnostic parameters of patient 14, such as intracardiac or intravascular pressure, activity, posture, respiration, or thoracic impedance. As another example, the user may use programmer 24 to retrieve information from IMD 16 regarding the performance or integrity of IMD 16 or other components of system 10, such as leads 18, 20, and 22, or a power source for IMD 16.

[0029] The user may use programmer 24 to program a pacing rate floor, a therapy progression, select electrodes for delivering a defibrillation shock, select a waveform for a defibrillation shock, or select or configure a fibrillation detection algorithm for IMD 16. The user may also use programmer 24 to program aspects of other therapies provided by IMD 16, such as cardioversion or pacing therapy. In some examples, the user may activate certain features of IMD 16 by entering a single command via programmer 24, such as pressing a single key or combination of keys of a keypad or making a single-point selection action with a pointing device.

[0030] IMD 16 and programmer 24 may communicate via wireless communication using any technology known in the art. Examples of communication technology may include, for example, low frequency or radio frequency (RF) telemetry, but other technologies are also contemplated. In some examples, programmer 24 may include a programming head that may be placed adjacent to the patient's body near the implant site of IMD 16 in order to improve the quality or safety of communication between IMD 16 and programmer 24.

[0031] Figure 2 yes Figure 110 is a more detailed conceptual diagram of IMD 16 and leads 18, 20, 22 of therapy system 10 of IMD 16. Leads 18, 20, 22 may be electrically coupled to a therapy delivery module (e.g., for delivering cardiac remodeling pacing therapy), a sensing module (e.g., for sensing one or more signals from one or more electrodes), and / or any other module of IMD 16 via connector block 34. In some examples, proximal ends of leads 18, 20, 22 may include electrical contacts that are electrically coupled to corresponding electrical contacts within connector block 34 of IMD 16. Additionally, in some examples, leads 18, 20, 22 may be mechanically coupled to connector block 34 by means of set screws, connecting pins, or another suitable mechanical coupling mechanism.

[0032] Each of leads 18, 20, 22 includes an elongated insulated lead body that can carry a plurality of conductors (e.g., concentric coil conductors, straight conductors, etc.) separated from one another by insulation (e.g., a tubular insulating sheath). In the illustrated example, bipolar electrodes 40, 42 are located near the distal tip of lead 18. Additionally, bipolar electrodes 44, 45, 46, 47 are located near the distal tip of lead 20, and bipolar electrodes 48, 50 are located near the distal tip of lead 22.

[0033] Electrodes 40, 44, 45, 46, 47, 48 may take the form of or define a ring electrode, and electrodes 42, 50 may take the form of or define an extendable spiral tip electrode retractably mounted within an insulated electrode head 52, 54, 56. Each of electrodes 40, 42, 44, 45, 46, 47, 48, 50 may be electrically coupled to a respective one of the conductors (e.g., coil conductors and / or straight conductors) within the lead body of its associated lead 18, 20, 22, and thereby to a respective one of the electrical contacts on the proximal tip of leads 18, 20, 22.

[0034] Electrodes 40, 42, 44, 45, 46, 47, 48, 50 may further be used to sense electrical signals (e.g., morphological waveforms within an electrogram (EGM)) associated with depolarization and repolarization of heart 12. The electrical signals are conducted to IMD 16 via corresponding leads 18, 20, 22. In some examples, IMD 16 may also deliver pacing pulses via electrodes 40, 42, 44, 45, 46, 47, 48, 50 to cause depolarization of cardiac tissue of the patient's heart 12. In some examples, such as Figure 2As shown, IMD 16 includes one or more housing electrodes (such as housing electrode 58), which can be integrally formed with an outer surface of a housing 60 (e.g., an airtight housing) of IMD 16 or otherwise coupled to housing 60. Any of electrodes 40, 42, 44, 45, 46, 47, 48, 50 can be combined with housing electrode 58 for unipolar sensing or pacing. It is generally understood by those skilled in the art that other electrodes can also be selected to define pacing and sensing vectors or for pacing and sensing vectors. Further, any of electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58 can be used to sense electrical activity during pacing therapy when not being used to deliver pacing therapy.

[0035] As reference Figure 2 As described in further detail, housing 60 may enclose a therapy delivery module that may include a stimulation generator for generating cardiac pacing pulses and defibrillation or cardioversion shocks and a sensing module for monitoring electrical signals of the patient's heart (e.g., the patient's heart rhythm). Leads 18, 20, 22 may also include elongated electrodes 62, 64, 66, respectively, which may be in the form of coils. IMD 16 may deliver defibrillation shocks to heart 12 via any combination of elongated electrodes 62, 64, 66 and housing electrodes 58. Electrodes 58, 62, 64, 66 may also be used to deliver cardioversion pulses to heart 12. Further, electrodes 62, 64, 66 may be made of any suitable conductive material, such as, but not limited to, platinum, platinum alloys, and / or other materials known to be useful in implantable defibrillation electrodes. Since electrodes 62, 64, 66 are generally not configured for pacing therapy, any of electrodes 62, 64, 66 may be used to sense electrical activity and may be used in combination with any of electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58. In at least one embodiment, RV elongated electrode 62 may be used to sense electrical activity of the patient's heart during delivery of pacing therapy (e.g., in combination with housing electrode 58 or a defibrillation electrode to housing electrode vector).

[0036] The above configuration of therapy system 10 is merely one example. In other examples, the therapy system may include epicardial leads and / or patch electrodes to replace or supplement Figure 1 In other embodiments, the therapy system 10 can be used in the absence of a transvenous lead (e.g., a leadless / wireless pacing system) or in the presence of a lead implanted (e.g., implanted transvenously or using a method) into the left chamber of the heart (as opposed to Figure 1The IMD 16 may be implanted in / around a septal region of the heart, in addition to or in lieu of a transvenous lead shown placed into the right chamber of the heart. In one example, a left ventricular (LV) coronary sinus lead 20 extends through one or more veins, the vena cava, the right atrium 26, and into the coronary sinus 30 to reach an area adjacent to the free wall of the left ventricle 32 of the heart 12. Additionally, in one or more embodiments, the IMD 16 may not be implanted in the patient 14. For example, the IMD 16 may deliver various cardiac therapies to the heart 12 via a percutaneous lead extending through the skin of the patient 14 to a plurality of locations within or outside the heart. In one or more embodiments, the system 10 may utilize wireless pacing (e.g., using energy transfer to an intracardiac pacing component via ultrasound, inductive coupling, RF, etc.) and sensing cardiac activation using electrodes on the housing / casing and / or on subcutaneous leads.

[0037] Other exemplary therapy systems for providing electrical stimulation therapy to heart 12 may include any suitable number of leads coupled to IMD 16, and each of these leads may extend to any location within or near heart 12. Such other therapy systems may include, for example, Figure 1 to Figure 2 Three transvenous leads are shown positioned. Still other therapy systems may include a single lead extending from IMD 16 into the right atrium 26 or two leads extending into the right atrium 26 and a respective one of the left atrium. In one example, IMD 16 as a cardiac resynchronization therapy (CRT) device with a left ventricular (LV) lead may be useful for HFpEF patients in the presence of complete AV nodal block because in such patients, the LV lead may be more beneficial than the RV lead. In some examples, it may be desirable to deliver rate-responsive pacing to the atria for HFpEF patients with chronotropic insufficiency having atrial leads (e.g., single-chamber atrial systems such as AAI) and atrial and ventricular lead systems (e.g., dual-chamber systems such as DDD and VDD).

[0038] Figure 3A8 is a functional block diagram of an exemplary configuration of IMD 16. As shown, IMD 16 may include a control module 81, a therapy delivery module 84 (e.g., which may include a stimulation generator), a sensing module 86, and a power source 90. Control module or device 81 may include computing device 80, memory 82, and telemetry module or device 88. Memory 82 may include computer-readable instructions that, when executed, for example, by computing device 80, cause IMD 16 and / or control module 81 to perform various functions attributed to IMD 16 and / or control module 81 as described herein. Further, memory 82 may include any volatile, non-volatile, magnetic, optical, and / or electrical media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, and / or any other digital media.

[0039] The computing device 80 of the control module 81 may include any one or more of the following: a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), and / or equivalent discrete or integrated logic circuits. In some examples, the computing device 80 may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, and / or one or more FPGAs, as well as other discrete or integrated logic circuits. The functions of the computing device 80 attributed to this article may be embodied in software, firmware, hardware, or any combination thereof.

[0040] The control module 81 may control the therapy delivery module or device 84 to deliver therapy (e.g., electrical stimulation therapy such as cardiac remodeling pacing) to the heart 12 in accordance with one or more selected therapy programs that may be stored in the memory 82 and based on an algorithm or method further described below. More specifically, the control module 81 (e.g., the computing device 80) may control various parameters of the electrical stimulation delivered by the therapy delivery module 84, such as AV delay, pacing pulses having amplitude, pulse width, frequency or electrode polarity, etc., which may be specified by one or more selected therapy programs (e.g., an adaptive pacing therapy program, a pacing rate lower limit determination, adjustment and / or modification program, an AV delay adjustment program, a pacing therapy program, a pacing recovery program, a capture management program, etc.). As shown, therapy delivery module 84 is electrically coupled to electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66, e.g., via conductors of respective leads 18, 20, 22 or, in the case of housing electrode 58, via electrical conductors disposed within housing 60 of IMD 16. Therapy delivery module 84 may be configured to generate and deliver electrical stimulation therapy, such as pacing therapy, to heart 12 using one or more of electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66.

[0041] For example, therapy delivery module 84 can deliver pacing stimulation (e.g., pacing pulses) via ring electrodes 40, 44, 45, 46, 47, 48 coupled to leads 18, 20, 22 and / or helical tip electrodes 42, 50 of leads 18, 22. Further, for example, therapy delivery module 84 can deliver a defibrillation shock to heart 12 via at least two of electrodes 58, 62, 64, 66. In some examples, therapy delivery module 84 can be configured to deliver pacing, cardioversion, or defibrillation stimulation in the form of electrical pulses. In other examples, therapy delivery module 84 can be configured to deliver one or more of these types of stimulation in the form of other signals such as sine waves, square waves, and / or other substantially continuous time signals.

[0042] The IMD 16 may further include a switch module or device 85, and the control module 81 (e.g., the computing device 80) may use the switch module 85 to select, for example, via a data / address bus, which of the available electrodes are used to deliver therapy, such as pacing pulses for pacing therapy, or which of the available electrodes are used for sensing. The switch module 85 may include a switch array, a switch matrix, a multiplexer, or any other type of switch device suitable for selectively coupling the sensing module or device 86 and / or the therapy delivery module 84 to one or more selected electrodes. More specifically, the therapy delivery module 84 may include a plurality of pacing output circuits. Each of the plurality of pacing output circuits may, for example, be selectively coupled to one or more of the electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66 (e.g., a pair of electrodes for delivering therapy to a bipolar or multipolar pacing vector) using the switch module 85. In other words, each electrode may be selectively coupled to one of the pacing output circuits of the therapy delivery module using the switch module 85 .

[0043] The sensing module 86 is coupled (e.g., electrically coupled) to a sensing device 99, which may include one or more optical sensors that monitor light signals, one or more mechanical heart activity sensors, and Figure 2 Electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66. The one or more optical sensors can be used to monitor systemic blood pressure, edema, pulse transit time, blood oxygen (e.g., using pulse oximetry), and the presence and concentration of serum biomarkers, etc. The one or more mechanical cardiac activity sensors may include any suitable transducer components (e.g., mounted within an implant device, mounted on a can of the device, etc.) for sensing cardiac motion (e.g., valve activity), such as a sonicator, accelerometer, or cardiac mechanical sensor (CMES) using embedded piezoelectric material. The electrodes can be used to monitor the electrical activity of the heart 12, such as electrocardiogram (ECG) / electrogram (EGM) signals and impedance signals. ECG / EGM signals can be used to measure or monitor activation time (e.g., ventricular activation time, etc.), heart rate (HR), heart rate variability (HRV), heart rate oscillations (HRT), deceleration / acceleration ability, deceleration sequence incidence, T wave alternans (TWA), P wave to P wave interval (also known as PP interval or AA interval), R wave to R wave interval (also known as RR interval or VV interval), P wave to QRS complex interval (also known as PR interval, AV interval or PQ interval), QRS complex morphology, ST segment (i.e., the segment connecting the QRS complex and T wave), T wave changes, QT interval, electrical carriers, etc.

[0044] The sensing device 99 can be connected via a Figure 1 to Figure 2 16, or may be wirelessly coupled to IMD 16 via telemetry module 88. In one or more embodiments, sensing device 99 or at least some of sensing devices 99 may be included as another implantable device, such as a subcutaneous implantable medical device. In other words, multiple implantable devices may interoperate to provide sensing capabilities, thereby providing diagnostic parameters, etc., as will be further described herein. Additionally, in some embodiments, multiple implantable medical devices may be utilized, each of which may be configured to independently or subordinately communicate with a plurality of implantable medical devices as described herein. Figure 5 The other computing devices described communicate with the external server. An example of a sensing device capable of providing pulse transmission time and thereby providing an alternative hemodynamic pressure can be found in particular in U.S. Patent No. 10,182,729, entitled "Systems and Methods for Monitoring Hemodynamic Status" and published on January 22, 2019, which is incorporated herein by reference in its entirety. Examples of sensing devices capable of providing impedance can be found in U.S. Patent No. 9,682,240, entitled "Cardiac Therapy Based Upon Impedance Signals" and published on June 20, 2017, and U.S. Patent No. 8,831,721, entitled "Pressure and Impedance Based Discrimination of Hemodynamic Stability Based on Pressure and Impedance" and published on September 9, 2014, each of which is incorporated herein by reference in its entirety.

[0045] The switch module 85 may also be used with the sensing module 86 to select which of the available electrodes to use or enable, for example, to sense electrical activity of the patient's heart (e.g., one or more electrical vectors of the patient's heart using any combination of electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66). Likewise, the switch module 85 may also be used with the sensing module 86 to select which of the available electrodes not to use (e.g., disable) to, for example, sense electrical activity of the patient's heart (e.g., one or more electrical vectors of the patient's heart using any combination of electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66), etc. In some examples, the control module 81 may select the electrodes to act as sensing electrodes by providing a signal via the switch module within the sensing module 86, for example, over a data / address bus.

[0046] In some examples, the sensing module 86 includes a channel including an amplifier having a relatively wider passband than an R-wave or P-wave amplifier. The signal from the selected sensing electrode can be provided to a multiplexer and thereafter converted by an analog-to-digital converter into a multi-bit digital signal for storage in the memory 82, for example, as an electrogram (EGM). In some examples, the storage of such an EGM in the memory 82 can be under the control of a direct memory access circuit.

[0047] In some examples, the control module 81 can operate as an interrupt driven device and can respond to interrupts from the pacemaker timing and control module, where the interrupts can correspond to the occurrence of sensed P waves and R waves and the generation of cardiac pacing pulses. Any mathematical calculations can be performed by the computing device 80, and any updates to values ​​or intervals controlled by the pacemaker timing and control module can be performed or occur after such interrupts. A portion of the memory 82 can be configured as a plurality of recirculating buffers capable of holding one or more series of measurement intervals that can be analyzed by, for example, the computing device 80 in response to the occurrence of a pacing or sensing interrupt to determine whether the patient's heart 12 is currently exhibiting an atrial or ventricular tachyarrhythmia.

[0048] In addition, computing device 80 of IMD 16 may detect a tachyarrhythmia episode, such as ventricular fibrillation, ventricular tachycardia, a rapid ventricular tachyarrhythmia episode, or an NST episode based on the electrocardiographic activity of heart 12 monitored via sensing module 86. For example, at electrodes 40, 42, 44, 46, 48, 50, 58, 62, 64, and 66 (at Figure 1 to Figure 2With the aid of at least some of the electrodes in the heart 12 (shown in FIG. 1 ), the sensing module 86 may generate an electrocardiogram (ECG) or electrogram (EGM) signal indicative of electrocardiographic activity. Alternatively, the sensing module 86 may be coupled to sensing electrodes ( ) that are separate from the stimulation electrodes that deliver electrical stimulation to the heart 12. Figure 1 to Figure 2 ), and may be coupled to one or more leads ( Figure 1 to Figure 2 ). The ECG signal may indicate depolarization of the heart 12.

[0049] For example, as previously described, in some examples, computing device 80 (e.g., a processor) may identify the presence of a tachyarrhythmia episode by detecting a threshold number of tachyarrhythmia episodes (e.g., RR or PP intervals having a duration less than or equal to a threshold). In some examples, computing device 80 may also identify the presence of a tachyarrhythmia episode by detecting variable coupling intervals between R waves of the cardiac signal.

[0050] Telemetry module 88 of control module 81 may include any suitable hardware, firmware, software, or any combination thereof for communicating with another device, such as a programmer or a mobile computing device (e.g., a smartphone). For example, under the control of computing device 80, telemetry module 88 may receive downlink telemetry from a programmer or mobile computing device and send uplink telemetry to it via an antenna (which may be internal and / or external). Computing device 80 may provide data to be uplinked to the programmer or mobile computing device and control signals for telemetry circuitry within telemetry module 88, for example, via an address / data bus. In some examples, telemetry module 88 may provide received data to computing device 80 via a multiplexer.

[0051] The various components of IMD 16 are further coupled to a power source 90, which may include a rechargeable or non-rechargeable battery. Non-rechargeable batteries may be selected to last for several years, while rechargeable batteries may be inductively charged from an external device, for example, on a daily or weekly basis.

[0052] Figure 3B1 is a functional block diagram depicting an embodiment of an IMD 16 having a bipolar RA lead 22, a bipolar RV lead 18 without LA CS pacing / sensing electrodes and coupled to an implantable pulse generator (IPG) circuit 31 having programmable modes and parameters of a biventricular DDD / R type known in the pacing art. In turn, a sensor signal processing circuit 91 is indirectly coupled to a timer circuit 43 via a data and control bus to a microcomputer circuit 33. The IPG circuit 31 is shown in the functional block diagram, which is generally divided into a microcomputer circuit 33 and a pacing circuit 21. The pacing circuit 21 includes a digital controller / timer circuit 43, an output amplifier circuit 51, a sense amplifier circuit 55, an RF telemetry transceiver 41, an activity sensor circuit 35, and other circuits and components described below.

[0053] Crystal oscillator circuit 89 provides a basic timing clock to pacing circuit 21 when power is provided by battery 29. Power-on reset circuit 87 is responsive to initial connection of the circuit to the battery for defining initial operating conditions, and similarly, in response to detecting a low battery condition, resets the operating state of the device. Reference mode circuit 37 generates a stable voltage reference and current for analog circuits within pacing circuit 21. Analog-to-digital converter (ADC) and multiplexer circuit 39 digitizes analog signals and voltages to provide, for example, real-time telemetry of cardiac signals from sense amplifier circuit 55 for uplink transmission via RF telemetry transceiver 41. Voltage reference and bias circuit 37, ADC and multiplexer circuit 39, power-on reset circuit 87, and crystal oscillator circuit 89 may correspond to any of those used in an exemplary implantable cardiac pacemaker.

[0054] If the IPG is programmed into rate-responsive mode, the signals output by one or more physiological sensors are used as rate control parameters (RCPs) to derive physiological escape intervals. For example, the escape interval is adjusted in proportion to the patient activity level generated in the patient activity sensor (PAS) circuit 35 in the exemplary IPG circuit 31. The patient activity sensor 27 is coupled to the IPG housing and can take the form of a piezoelectric crystal transducer. The output signal of the patient activity sensor 27 can be processed and used as an RCP. The sensor 27 generates an electrical signal in response to sensed physical activity, which is processed by the activity circuit 35 and provided to the digital controller / timer circuit 43. Similarly, the exemplary systems, devices, and methods described herein can be practiced in conjunction with alternative types of sensors (such as oxygenation sensors, pressure sensors, pH sensors, temperature sensors, respiration sensors, perfusion sensors, heart sound sensors, heart rate sensors, and pulse emission time sensors) using one or more different modalities (e.g., optical, acoustic, electronic, etc.) to provide rate-responsive pacing capabilities. For example, impedance can be measured using a ring electrode on a lead (e.g., RA or RV lead), and temperature can be measured by a sensor at the distal end of the lead. Alternatively, QT time can be used as a rate-indicating parameter, in which case no additional sensor is required. Similarly, the illustrative embodiments described herein can also be practiced in a non-rate-responsive pacemaker.

[0055] Data transmission to and from the external programmer is accomplished through telemetry antenna 57 and associated RF telemetry transceiver 41 for both demodulating received downlink telemetry and transmitting uplink telemetry. The uplink telemetry capability may include the ability to transmit stored digital information, such as rate modification information, such as diagnostic parameters, pacing rate floors, activity information, rate response pacing information, operating modes and parameters, EGM histograms and other events, as well as real-time EGMs of atrial and / or ventricular electrical activity and marker channel pulses indicating the occurrence of sensed and paced depolarizations in the atria and ventricles.

[0056] The microcomputer circuit 33 contains a computing device 80 and an associated system clock and an on-processor RAM chip 82A and a ROM chip 82B. In addition, the microcomputer circuit 33 includes a separate RAM / ROM chip 82C to provide additional memory capacity. The computing device 80 typically operates in a reduced power consumption mode and is interrupt driven. The computing device 80 is awakened in response to defined interrupt events, which may include A-TRIG, RV-TRIG, LV-TRIG signals generated by the timer in the digital timer circuit 43 and A-EVENT, RV-EVENT and LV-EVENT signals generated by the sense amplifier circuit 55, etc. The specific values ​​of the intervals and delays timed out by the digital controller / timer circuit 43 are controlled by the microcomputer circuit 33 from the programmed parameter values ​​and operating modes via the data and control bus. In addition, if programmed to operate as a rate-responsive pacemaker, a timed interrupt (e.g., every cycle or every two seconds) can be provided to allow the microprocessor to analyze the activity sensor data and update the basic pacing rate and AA, VA (if applicable). In addition, computing device 80 may also be used to define variable, actionable AV delay intervals, and the amount of energy delivered to each ventricle and / or atrium. Additionally, for example, after each time interruption, the patient's intrinsic heart rate may be measured and compared to the pacing rate lower limit to determine whether to deliver pacing therapy to maintain the patient's heart rate at or above the pacing rate lower limit.

[0057] In one embodiment, computing device 80 is a custom microprocessor adapted to fetch and execute instructions stored in RAM / ROM memory 82 in a conventional manner. However, it is contemplated that other embodiments may be suitable for practicing the disclosed methods. For example, an off-the-shelf commercially available microprocessor or microcontroller or a custom dedicated hardwired logic or state machine type circuit may perform the functions of computing device 80.

[0058] The digital controller / timer circuit 43 operates under the general control of the microcomputer circuit 33 to control the timing and other functions within the pacing circuit 21, and includes a set of timing and associated logic circuits, some of which are depicted that are relevant to the present disclosure. The depicted timing circuits include a URI / LRI timer 83A, a VV delay timer 83B, an intrinsic interval timer 83C for timing the elapsed V-EVENT to V-EVENT interval or V-EVENT to A-EVENT interval, an escape interval timer 83D for timing the AA and / or VA pacing escape interval, an AV delay interval timer 83E for timing the A-LVp delay (or A-RVp delay) from a previous A-EVENT or A-TRIG, a post-ventricular timer 83F for timing the post-ventricular time period, and a date / time clock 83G.

[0059] The AV delay interval timer 83E is loaded with the appropriate delay interval for one ventricular chamber (e.g., A-RVp delay or A-LVp) to time out from a previous A-PACE or A-EVENT. The interval timer 83E triggers pacing stimulus delivery and may be based on one or more previous cardiac cycles (or based on a data set empirically derived for a given patient).

[0060] The post-event timer 83F times out the post-ventricular time period following an RV-EVENT or LV-EVENT or RV-TRIG or LV-TRIG and the post-atrial time period following an A-EVENT or A-TRIG. The duration of the post-event time period may also be selected as a programmable parameter stored in the microcomputer circuit 33. The post-ventricular time period includes the post-ventricular atrial blanking period (PVARP), the post-atrial ventricular blanking period (PAVBP), the ventricular blanking period (VBP), and the ventricular refractory period (VRP), but other time periods may be appropriately defined based at least in part on the operating circuitry employed in the pacing engine. The post-atrial time period includes the atrial refractory period (ARP), during which the A-EVENT is ignored for the purpose of resetting any AV delay, and during which atrial sensing is disabled. It should be noted that the start of the post-atrial time period and AV delay may begin substantially simultaneously with the start or end of each A-EVENT or A-TRIG, or in the latter case, at the end of A-PACE, which may follow an A-TRIG. Similarly, the start of the post-ventricular time period and VA escape interval may begin substantially simultaneously with the start or end of a V-EVENT or V-TRIG, or in the latter case, at the end of V-PACE, which may follow a V-TRIG. The computing device 80 also optionally calculates the AV delay, post-ventricular time period, and post-atrial time period as a function of sensor-based escape intervals and / or intrinsic atrial and / or ventricular rates established in response to the RCP.

[0061] The output amplifier circuit 51 contains an RA pace pulse generator (and a LA pace pulse generator if LA pacing is provided), an RV pace pulse generator, an LV pace pulse generator, and / or any other pulse generator configured to provide atrial and ventricular pacing. To trigger the generation of an RV-PACE or LV-PACE pulse, the digital controller / timer circuit 43 may use the algorithm described below.

[0062] Output amplifier circuit 51 includes switching circuitry for coupling selected pacing electrode pairs from among the lead conductors and IND-CAN electrodes to the RA pacing pulse generator (and LA pacing pulse generator, if provided), RV pacing pulse generator, and LV pacing pulse generator. Pace / sense electrode selection and control circuitry 53 selects lead conductors and associated pacing electrode pairs for coupling to atrial and ventricular output amplifiers within output amplifier circuit 51 for achieving RA, LA, RV, and LV pacing.

[0063] The sense amplifier circuit 55 contains sense amplifiers for atrial and ventricular pacing and sensing. High impedance P-wave and R-wave sense amplifiers can be used to amplify the voltage difference signal generated across the sensing electrode pair due to the passage of the cardiac depolarization wavefront. The high impedance sense amplifier uses high gain to amplify low amplitude signals and relies on passband filters, time domain filtering, and amplitude threshold comparisons to distinguish the P-wave or R-wave from background electrical noise. The digital controller / timer circuit 43 controls the sensitivity setting of the atrial and ventricular sense amplifier circuit 55.

[0064] During blanking periods before, during, and after delivery of a pacing pulse to any of the pacing electrodes of the pacing system, the sense amplifier can be decoupled from the sense electrode to avoid saturation of the sense amplifier. The sense amplifier circuit 55 includes a blanking circuit for decoupling the selected lead conductor pairs and IND-CAN electrodes from the inputs of the RA sense amplifier (and LA sense amplifier, if provided), RV sense amplifier, and LV sense amplifier during ABP, PVABP, and VBP. The sense amplifier circuit 55 also includes a switching circuit for coupling the selected sensing electrode lead conductors and IND-CAN electrodes to the RA sense amplifier (and LA sense amplifier, if provided), RV sense amplifier, and LV sense amplifier. Similarly, the sense electrode selection and control circuit 53 selects the conductors and associated sensing electrode pairs to be coupled to the atrial and ventricular sense amplifiers within the output amplifier circuit 51 and the sense amplifier circuit 55 for achieving RA, LA, RV, and LV sensing along the desired unipolar and bipolar sensing vectors.

[0065] A right atrial depolarization or P wave in the RA-SENSE signal sensed by the RA sense amplifier results in a RA-EVENT signal that is transmitted to the digital controller / timer circuit 43. Similarly, a left atrial depolarization or P wave in the LA-SENSE signal sensed by the LA sense amplifier (if provided) results in a LA-EVENT signal that is transmitted to the digital controller / timer circuit 43. A ventricular depolarization or R wave in the RV-SENSE signal sensed by the ventricular sense amplifier results in a RV-EVENT signal that is transmitted to the digital controller / timer circuit 43. Similarly, a ventricular depolarization or R wave in the LV-SENSE signal sensed by the ventricular sense amplifier results in a LV-EVENT signal that is transmitted to the digital controller / timer circuit 43. The RV-EVENT, LV-EVENT and RA-EVENT, LA-SENSE signals may be refractory or refractory and may be inadvertently triggered by an electrical noise signal or an abnormally conducted depolarization wave rather than a true R-wave or P-wave.

[0066] Figure 4is a block diagram of an exemplary programmer 24. Figure 4 As shown, programmer 24 includes a processor 100, a memory 102, a user interface 104, a telemetry module 106, and a power source 108. Programmer 24 may be a dedicated hardware device with dedicated software for programming IMD 16. Alternatively, programmer 24 may be an off-the-shelf computing device (e.g., a mobile computing device such as a smart phone) running an application that enables programmer 24 to program IMD 16.

[0067] A user may use programmer 24 to select a therapy program (e.g., a set of stimulation parameters), create a new therapy program, modify a therapy program through individual or global adjustments, or send a new program to a medical device, such as IMD 16 ( Figure 1 ). A clinician may interact with programmer 24 via user interface 104, which may include a display that presents a graphical user interface to the user, and a keypad or another mechanism for receiving input from the user.

[0068] Processor 100 may take the form of one or more microprocessors, DSPs, ASICs, FPGAs, programmable logic circuits, etc., and the functions attributed to processor 100 herein may be embodied in hardware, firmware, software, or any combination thereof. Memory 102 may store instructions that cause processor 100 to provide the functions attributed to programmer 24 herein, as well as information used by processor 100 to provide the functions attributed to programmer 24 herein. Memory 102 may include any fixed or removable magnetic, optical, or electrical media, such as RAM, ROM, CD-ROM, hard or floppy disks, EEPROM, etc. Memory 102 may also include a removable memory portion that may be used to provide memory updates or increases in memory capacity. Removable memory may also allow IMD and / or patient data to be easily transferred to another computing device, or to be removed before programmer 24 is used to program therapy for another patient. Memory 102 may also store information that controls therapy delivery by IMD 16, such as stimulation parameter values.

[0069] Programmer 24 may communicate wirelessly with IMD 16, such as using RF communication or proximal inductive interaction. Such wireless communication is possible through the use of telemetry module 106, which may be coupled to an internal antenna or an external antenna. The external antenna coupled to programmer 24 may correspond to a programming head that may be placed on heart 12, as described above with reference to Figure 1 The telemetry module 106 may be similar to the telemetry module 88 ( Figure 3A ).

[0070] Telemetry module 106 may also be configured to communicate with another computing device via wireless communication techniques or directly with another computing device through a wired connection. Examples of local wireless communication techniques that may be used to facilitate communication between programmer 24 and another computing device include RF communications according to the 802.11 or Bluetooth specification sets, infrared communications according to, for example, the IrDA standard or other standards or proprietary telemetry protocols. In this way, other external devices may be able to communicate with programmer 24 without establishing a secure wireless connection.

[0071] Power supply 108 delivers operating power to the components of programmer 24. Power supply 108 may include a battery and a power generation circuit for generating operating power. In some embodiments, the battery may be rechargeable to allow extended operation. Recharging may be achieved by electrically coupling power supply 108 to a bracket or plug connected to an alternating current (AC) outlet. In addition or alternatively, recharging may be achieved by proximal inductive interaction between an external charger and an inductive charging coil within programmer 24. In other embodiments, conventional batteries (e.g., nickel-cadmium or lithium-ion batteries) may be used. In addition, programmer 24 may be directly coupled to an AC outlet to power programmer 24. Power supply 108 may include a circuit for monitoring the remaining power in the battery. In this way, user interface 104 may provide a current battery charge indicator or provide a low battery charge indicator when the battery needs to be replaced or recharged. In some cases, power supply 108 may be able to estimate the remaining operating time using the current battery.

[0072] Figure 5 is a block diagram illustrating a system 190 according to one embodiment, the system including an external device 192 such as a server and a Figures 1 to 4 1 and one or more computing devices 194A-194N of programmer 24. In this embodiment, IMD 16 may communicate with programmer 24 via a first wireless connection using its telemetry module 88, and with access point 198 via a second wireless connection. Figure 5 In the example of FIG1 , access point 198, programmer 24, external device 192, and computing devices 194A-194N are interconnected and capable of communicating with each other via network 196. In some cases, one or more of access point 198, programmer 24, external device 192, and computing devices 194A-194N may be coupled to network 196 via one or more wireless connections. IMD 16, programmer 24, external device 192, and computing devices 194A-194N may each include or contain one or more processors, such as one or more microprocessors, DSPs, ASICs, FPGAs, programmable logic circuits, etc., that may perform various functions and operations, such as those described herein.

[0073] Access point 198 may include or comprise a device that connects to network 196 via any of a variety of connections, such as a cellular data connection, a telephone dial-up, a digital subscriber line (DSL), or a cable modem connection. In other examples, access point 198 may be coupled to network 196 via different forms of connection, including a wired connection or a wireless connection. In some examples, access point 198 may communicate with programmer 24 and / or IMD 16. Access point 198 may be co-located with patient 14 (e.g., in the same room or same location as patient 14), or may be located remotely from patient 14. For example, access point 198 may be a home monitor that is located in the patient's home or that is conveniently carried by patient 14.

[0074] During operation, IMD 16 may collect, measure, and store various forms of diagnostic data, such as diagnostic parameters that may be used by the illustrative systems, methods, and processes to determine or generate a lower limit for a pacing rate. In some cases, IMD 16 may directly analyze the collected diagnostic data and generate any corresponding reports or alarms. However, in some cases, IMD 16 may send diagnostic data, such as diagnostic parameters, wirelessly or via access point 198 and network 196 to programmer 24, access point 198, and / or external device 192 for remote processing and analysis (e.g., to determine a lower limit for a pacing rate).

[0075] In another example, IMD 16 may provide the collected diagnostic data or parameters to external device 192 via access point 198 and network 196. External device 192 includes one or more processors 200. In some cases, external device 192 may request such data, and in some cases, IMD 16 may automatically or periodically provide such data to external device 192. Upon receiving the diagnostic data via input / output device 202, external device 192 may be able to analyze the data and generate a report, alarm, or other value (e.g., a pacing rate lower limit).

[0076] One or more of computing devices 194A-194N may access diagnostic data or parameters via network 196 for use in determining or generating a pacing rate lower limit. In some cases, external device 192 may automatically send the generated pacing rate lower limit to one or more of computing devices 194A-194N via input / output device 202. In some cases, external device 192 may automatically or upon request send the pacing rate lower limit to another device, such as programmer 24. In some cases, external device 192 may display the pacing rate lower limit to a user via input / output device 202.

[0077] In one embodiment, external device 192 may include a secure storage site for diagnostic data or information that has been collected from IMD 16 and / or programmer 24. In an embodiment, network 196 may include the Internet, and a trained professional, such as a clinician, may use computing devices 194A-194N to securely access diagnostic data or parameters or pacing rate lower limits stored on external device 192. For example, a trained professional may utilize a secure username and password to access information stored on external device 192. In one embodiment, external device 192 may be a CareLink server provided by Medtronic, Inc. of Minneapolis, Minnesota.

[0078] For example, use Figures 1 to 5 An exemplary method 300 of a system and apparatus for determining a lower limit on a pacing rate is depicted in Figure 6 The illustrative method 300 utilizes the rate modification information for a specific patient to determine a pacing rate lower limit for a pacing device for a specific patient. In other words, the illustrative method 300 can customize the pacing rate lower limit for a specific patient and the patient's specific condition. It should be understood that during adaptive pacing therapy, the pacing rate lower limit can change based on one or more factors such as activity level, and therefore, the determined pacing rate lower limit described herein is a baseline pacing rate lower limit, which can be increased during adaptive pacing therapy.

[0079] Prior to determining a pacing rate lower limit, method 300 first obtains rate modification information 301. Rate modification information may be described as any information specific to a patient that may be related to a pacing rate lower limit so as to be able to be used to determine a pacing rate lower limit for the patient (e.g., an optimized pacing rate lower limit). Rate modification information may be categorized into one or more of a plurality of different categories. For example and as shown, rate modification information may include a physical characteristic 302 of a patient, a pathology 304 of a patient, a diagnostic parameter 306 of a patient, a device configuration 308 of a pacing device, and patient reported information 310, each of which will be further described herein.

[0080] Physical characteristics 302 may include, among other things, height, sex, age, body mass index (BMI), body surface area, physical fitness level, and activity level. Pathology 304 may include diastolic dysfunction / heart failure with preserved ejection fraction, systolic dysfunction, chronotropic insufficiency, worsening of heart failure, and comorbidities. Diagnostic parameters 306 may include, among other things, ventricular contractility, ventricular stiffness, pulse transit time, resting heart rate, nocturnal heart rate, arrhythmia burden, target pacing burden, heart rate recovery, impedance, fluid overload, edema, respiratory rate, maximum heart rate, ejection fraction, left ventricular pressure, systemic blood pressure, pulmonary artery pressure, blood oxygenation, and the presence or concentration of serum biomarkers. Device configuration 308 may include, among other things, ventricular pacing electrode location, atrial pacing electrode location, and pacing therapy type. Patient reported information 310 may include, among other things, energy level, peripheral edema, desired activity performance, and pacing-related symptoms.

[0081] It should be understood that although as described herein and Figure 6 301 , the present disclosure contemplates more than five and less than five different categories of rate modification information. In addition, although the different categories of rate modification information each include a plurality of different data or information items, less than all of the different data items in the five categories (e.g., such as one data item, two data items, three data items, etc.) may be obtained and later utilized by the illustrative method 300. For example, a single data or information item such as age may be obtained 301 and then later used to determine a patient's lower pacing rate limit. In addition, for example, a single data or information item such as pathology of diastolic dysfunction / heart failure with preserved ejection fraction may be obtained 301 and then later used to determine a patient's lower pacing rate limit. Further, for example, two data or information items such as patient-reported diagnostic parameters of desired activity performance and nighttime heart rate may be obtained 301 and then later used to determine a patient's lower pacing rate limit.

[0082] In addition, the rate modification information may be obtained from one or more of a number of different sources, such as computer systems and medical devices, such as a pacing device implanted in a patient, an external ECG monitoring system, other implanted medical devices, a watch, etc. For example, a user, such as a clinician, may enter or input the rate modification information into a computer system configured to obtain the rate modification information. More specifically, for example, a nurse may measure a patient's physical characteristics and then input them into a computer system, such as a programmer 24, a computing device 194n, and an external device 192 described herein. Additionally, the rate modification information may be obtained from an electronic medical record system, such as located on an external device 192, via a network 196 described herein. Additionally, the pacing device implanted in the patient and / or another medical device associated with and monitoring the patient may obtain various rate modification information, such as pathology 304, diagnostic parameters 306, and / or device configuration 308. More specifically, for example, an IMD implanted in a patient can report to one or more additional systems (such as programmer 24, computing device 194n, and external device 192 described herein) the type of therapy provided to the patient, the patient's heart rate, the patient's resting heart rate, etc. Additionally, patient reported information 310 may be obtained by the patient entering or entering such information into a mobile computing device 301. In one or more embodiments, the mobile computing device may ask the patient a series of questions, the answers to which may include rate modification information.

[0083] Upon obtaining the at least one piece or items of rate modification information 301, the exemplary method 300 may then determine a pacing rate lower limit based on the at least one piece or items of rate modification information 320. In other words, the rate modification information may be utilized to calculate or generate a pacing rate lower limit for the patient. It should be appreciated that the determination 320 may be performed or occur on a variety of different devices or systems, such as the IMD 16, the programmer 24, the computing device 194n, and the external device 192.

[0084] The determination of the pacing rate lower limit 320 may utilize a defined relationship or function between at least one or more rate modification information and a pacing rate lower limit generated from, for example, clinical data. For example, as altitude decreases, the pacing rate lower limit may be higher than a default pacing rate lower limit (e.g., the default pacing rate lower limit may be approximately 60 beats per minute). Further, for example, if the patient is female, the pacing rate lower limit may be higher than the default pacing rate lower limit, and if the patient is male, the pacing rate lower limit may be lower than the default pacing rate lower limit. Further, for example, the younger the patient, the higher the default pacing rate lower limit. Further, for example, as body mass index increases, the pacing rate lower limit may be higher than the default pacing rate lower limit. And further, for example, as body surface area decreases, the pacing rate lower limit may be higher than the default pacing rate lower limit. Further, as the patient's physical health declines, the pacing rate lower limit may be higher than the default pacing rate lower limit. Finally, as the patient's activity level increases, the pacing rate lower limit can be increased above the default pacing rate lower limit.

[0085] With respect to diagnostic parameters, for example, as ventricular stiffness increases, the pacing rate lower limit may be higher than the default pacing rate lower limit. Also, for example, as pulse emission time decreases, the pacing rate lower limit may be higher than the default pacing rate lower limit. Also, for example, as resting heart rate and / or nighttime heart rate increases, the pacing rate lower limit may be higher than the default pacing rate lower limit. Still further, for example, the pacing rate lower limit may be increased to be greater than the default pacing rate lower limit to increase the pacing burden. Still further, for example, as ejection fraction increases, the pacing rate lower limit may be higher than the default pacing rate lower limit. Still further, for example, as edema increases, the pacing rate lower limit may be increased to be higher than the default pacing rate lower limit, and conversely, as edema decreases, the pacing rate lower limit may be decreased to be lower than the default pacing rate lower limit. Still further, for example, as blood pressure increases, the pacing rate lower limit may be increased to be higher than the default pacing rate lower limit. Further, for example, as pulmonary artery pressure increases, the pacing rate lower limit may be increased above the default pacing rate lower limit. And further, for example, for a biomarker such as NT-proBNP, as NT-proBNP increases, the pacing rate lower limit may be increased above the default pacing rate lower limit.

[0086] In addition, with respect to pathology, for example, if the patient has diastolic dysfunction, the pacing rate lower limit may be higher than the default pacing rate lower limit. In addition, for example, if the patient has systolic dysfunction, the pacing rate lower limit may be lower than the default pacing rate lower limit to, for example, minimize the pacing percentage. Still further, for example, if the patient has chronotropic insufficiency, the pacing rate lower limit may be higher than the default pacing rate lower limit (to, for example, compensate for insufficient heart rate during exercise). Additionally, if the patient has the pathology of heart failure with preserved ejection fraction (HFpEF), the pacing rate lower limit may be determined to be higher than the default pacing rate lower limit. Additionally, if the patient has the pathology of heart failure with reduced ejection fraction (HFrEF), the pacing rate lower limit may be determined to be lower than the default pacing rate lower limit.

[0087] Additionally, with respect to device characteristics, for example, if cardiac conduction system pacing is the type of pacing therapy being delivered (e.g., the pacing electrodes are positioned to pace the cardiac conduction system), the pacing rate lower limit may be higher than the default pacing rate lower limit. Additionally, for example, if the pacing device is configured to deliver cardiac resynchronization therapy pacing, the pacing rate lower limit may be higher than the default pacing rate lower limit.

[0088] When using patient reported information, the process can be designed to determine the pacing rate lower limit to minimize undesirable symptoms or conditions and / or meet patient expectations, such as a desired performance level. For example, if the patient reports one or more undesirable symptoms, the pacing rate lower limit can be lower than the default pacing rate lower limit or reduced from its current value. In addition, for example, if the patient provides patient reported information that the patient desires an increased physical performance level, the pacing rate lower limit can be increased incrementally over a period of time until the patient reports the undesirable symptoms. In this way, the pacing rate lower limit can be "titrated" by the patient to find the optimal pacing rate lower limit for the patient in the current state. For example, if the patient reports a low energy level, the pacing rate lower limit can be higher than the default pacing rate lower limit.

[0089] Additionally, it should be appreciated that having an increased pacing rate lower limit (e.g., above a default pacing rate lower limit) may result in undesirable effects because, for example, the pacing device may pace a higher percentage of the time, which may be undesirable when utilizing a conventional pacing location (e.g., the RV apex). Nonetheless, when utilizing cardiac conduction system pacing, pacing a higher percentage of the time may not achieve the same undesirable effects. Thus, if the type of pacing is conventional myocardial tissue pacing, it may be determined not to increase the pacing rate lower limit above the default pacing rate lower limit, and if the type of pacing is cardiac conduction system pacing, it may be determined to increase the pacing rate lower limit above the default pacing rate lower limit.

[0090] After determining the pacing rate lower limit 320, the pacing device may be configured or programmed with the pacing rate lower limit 330. In one or more embodiments, the determined pacing rate lower limit may be presented or displayed to a clinician for review, potential adjustment, and approval prior to configuring the patient's pacing device. In embodiments where the pacing rate lower limit determination occurs in the pacing device itself, the pacing device itself may reconfigure itself with the newly determined pacing rate lower limit. In other words, determining the pacing rate lower limit may be performed or implemented by a pacing device such as an IMD 16. Additionally, in one or more embodiments, the pacing rate lower limit may be determined using one or more of the computing device 194n and the external device 192 described herein, and may then be sent to the pacing device via the network 196 and / or the programmer 24. In other words, a remote computing device may perform or implement the determination of the pacing rate lower limit.

[0091] Additionally, it should be appreciated that method 300 may be performed cyclically or iteratively over a period of time, such as once a day, once a week, once a month, once every three months, etc. In this manner, the pacing rate lower limit of the pacing device may be updated to correspond to the patient's changing condition, updated clinical data indicating how the rate modification information relates to or corresponds to the pacing rate lower limit, etc. For example, the pacing device may monitor or obtain the left ventricular ejection fraction and then periodically determine the pacing rate lower limit based on the left ventricular ejection fraction.

[0092] An exemplary graphical user interface 400 for determining a pacing rate lower limit, for example using Figures 1 to 6 Systems, devices and methods for implanting a pacing device. A clinician may use a graphical user interface 400 to determine a pacing rate lower limit for a patient at the time of implantation or during a follow-up consultation. The graphical user interface 400 includes an input area 402 configured for the clinician to input or enter some optional preferences. Specifically, the input area 402 includes a lower boundary input area, an upper boundary input area, and a pacing desired percentage input area, each of which may be selected (e.g., touched, clicked, etc.) by the clinician to enter a value therein. The lower boundary input area may allow the clinician to enter a lower boundary or limit of the pacing to be delivered to the patient, and the upper boundary input area may allow the clinician to enter an upper boundary or limit of the pacing to be delivered to the patient. The pacing desired percentage input area may allow the clinician to enter the desired time % for the patient to optimally receive pacing therapy. When determining or generating a pacing rate lower limit, the exemplary method and process for determining the pacing rate lower limit 320 may take into account each of the lower boundary, upper boundary, and desired pacing %. For example, the determined pacing rate lower limit will not exceed the upper boundary or be less than the lower boundary, and may be determined such that a % of the desired pacing time may not be exceeded.

[0093] After optionally entering a value into input area 402, the clinician may select Generate Pacing Rate Lower Limit area 404, which may utilize method 300 described herein in conjunction with the value entered into input area 402 to generate a pacing rate lower limit, which is displayed in pacing rate lower limit display area 406. Thereafter and upon review, the clinician may select Configure Pacing Device area 408 to configure the pacing device utilizing the generated pacing rate lower limit.

[0094] Example

[0095] Embodiment Ex1: A method comprising:

[0096] obtaining, using the pacing device, rate modification information including at least one physical characteristic of the patient; and

[0097] A pacing rate lower limit of the pacing device is determined based on the obtained rate modification information, wherein the pacing rate lower limit is used by the pacing device to initiate pacing in response to the patient's intrinsic rate being less than the pacing rate lower limit.

[0098] Embodiment Ex2: A system comprising:

[0099] A computing device comprising one or more processors and configured to:

[0100] obtaining, using the pacing device, rate modification information including at least one physical characteristic of the patient; and

[0101] A pacing rate lower limit of the pacing device is determined based on the obtained rate modification information, wherein the pacing rate lower limit is used by the pacing device to initiate pacing in response to the patient's intrinsic rate being less than the pacing rate lower limit.

[0102] Embodiment Ex3: An implantable medical device, comprising:

[0103] one or more electrodes for delivering cardiac pacing therapy to a patient's heart and sensing electrical activity from the patient's heart; and

[0104] A computing device operably coupled to the one or more electrodes and comprising one or more processors, the computing device configured to:

[0105] monitoring the patient's intrinsic heart rate using the one or more electrodes;

[0106] delivering pacing therapy to the patient's heart in response to the patient's intrinsic rate being less than a lower pacing rate limit;

[0107] obtaining, using the pacing device, rate modification information including at least one physical characteristic of the patient; and

[0108] A lower pacing rate limit of the pacing device is determined based on the obtained rate modification information.

[0109] Embodiment Ex4: According to the method described in embodiment Ex1, the system described in embodiment Ex2 or the device described in embodiment Ex3, wherein the at least one physical characteristic includes one or more of height, gender, age, body mass index (BMI), body surface area, physical fitness level and activity level.

[0110] Embodiment Ex5: A method, system or apparatus according to any one of embodiments Ex1 to Ex4, wherein the rate modification information further comprises at least one pathology, wherein the at least one pathology comprises diastolic dysfunction / heart failure with preserved ejection fraction.

[0111] Embodiment Ex6: A method, system or device according to any one of embodiments Ex1 to Ex5, wherein the rate modification information also includes at least one pathology, wherein the at least one pathology includes one or more of systolic dysfunction, chronotropic insufficiency, worsening heart failure and comorbidities.

[0112] Embodiment Ex7: A method, system or device according to any one of embodiments Ex1 to Ex6, wherein the rate modification information also includes at least one diagnostic parameter, wherein the at least one diagnostic parameter includes one or more ventricular contractility, ventricular stiffness, pulse conduction time, resting heart rate, nocturnal heart rate, arrhythmia burden, target pacing burden, heart rate recovery, impedance, fluid overload, edema, respiratory rate, maximum heart rate, ejection fraction, left ventricular pressure, systemic blood pressure, pulmonary artery pressure, blood oxygen, and the presence or concentration of serum biomarkers.

[0113] Embodiment Ex8: A method, system or device according to embodiment Ex7, wherein obtaining rate modification information includes monitoring the at least one diagnostic parameter of the patient using the pacing device.

[0114] Embodiment Ex9: A method, system or device according to any one of embodiments Ex1 to Ex8, wherein the rate modification information also includes at least one device configuration, wherein the at least one device configuration includes one or more of a ventricular pacing electrode position, an atrial pacing electrode position and a pacing therapy type.

[0115] Embodiment Ex10: A method, system or device according to any one of embodiments Ex1 to Ex9, wherein the rate modification information also includes patient-reported information, wherein the patient-reported information includes one or more of energy level, peripheral edema, desired activity performance and pacing-related symptoms.

[0116] Embodiment Ex11: The method, system or device of any one of Embodiments Ex1 to Ex10, wherein the rate modification information further comprises patient reported information, wherein the patient reported information is obtained from a mobile computing device.

[0117] Embodiment Ex12: The method or system according to any one of embodiments Ex1 to Ex2 and Ex4 to Ex11, wherein the method further comprises or the computing device is further configured to execute configuring the pacing device with the pacing rate lower limit.

[0118] Embodiment Ex13: The method, system or apparatus according to any one of Embodiments Ex1 to Ex12, wherein obtaining the rate modification information comprises obtaining the rate modification information from an electronic medical record system.

[0119] Embodiment Ex14: The method according to any one of embodiments Ex1 and Ex4 to Ex10, wherein determining a pacing rate lower limit of the pacing device based on the obtained rate modification information is performed by the pacing device.

[0120] Embodiment Ex15: A method or system according to any one of embodiments Ex1 to Ex2 and Ex4 to Ex14, wherein determining the lower limit of the pacing rate of the pacing device based on the obtained rate modification information is performed by a remote computing system communicatively coupled to the pacing device.

[0121] It should be understood that the various aspects disclosed herein may be combined in combinations different from those specifically presented in the specification and drawings. It should also be understood that, depending on the example, certain actions or events of any of the processes or methods described herein may be performed in a different order, may be added, merged, or omitted entirely (e.g., not all described actions or events may be required to perform these techniques). In addition, although for clarity, certain aspects of the present disclosure are described as being performed by a single module or unit, it should be understood that the techniques of the present disclosure may be performed by a combination of units or modules associated with, for example, a medical device.

[0122] In one or more examples, the described methods, processes, and techniques (including those attributed to IMD 16, programmer 24, external device 192, and computing device 194N) may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or codes on a computer-readable medium and executed by a hardware-based processing unit. A computer-readable medium may include a computer-readable storage medium, which corresponds to a tangible medium, such as a data storage medium (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and can be accessed by a computer).

[0123] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits. The terms "computing device," "controller," "module," "processor," or "processing circuit" may generally refer to any of the aforementioned logic circuits, alone or in combination with other logic circuits, or any other equivalent circuit. In addition, these techniques may be fully implemented in one or more circuits or logic elements. Describing different features as modules or units is intended to highlight different functional aspects, and does not necessarily imply that such modules or units must be implemented by separate hardware or software components. On the contrary, the functions associated with one or more modules or units may be performed by separate hardware or software components, or integrated in common or separate hardware or software components.

[0124] All references and publications cited herein are expressly incorporated by reference in their entirety for all purposes unless in any respect directly inconsistent with this disclosure.

[0125] Unless otherwise indicated, all numerical values ​​expressing feature sizes, amounts, and physical properties used in the specification and claims may be understood to be modified by the terms "exactly" or "about." Therefore, unless otherwise indicated, the numerical parameters set forth in the foregoing specification and the appended claims are approximations that may vary depending upon the desired properties sought to be obtained by one skilled in the art utilizing the teachings disclosed herein or, for example, within typical ranges of experimental error.

[0126] As used herein, the term "configured to" may be used interchangeably with the terms "adapted to" or "structured to," unless the context of the present disclosure clearly dictates otherwise.

[0127] The singular forms "a," "an," and "the" encompass embodiments having plural referents, unless the context clearly dictates otherwise.

[0128] As used herein, "having", "including", "comprising", etc. are used in their open-ended sense and generally mean "including but not limited to". It should be understood that "consisting essentially of", "consisting of", etc. are subsumed under "comprising", etc.

[0129] References to "one embodiment," "an embodiment," "certain embodiments," or "some embodiments," etc., mean that a particular feature, configuration, composition, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present disclosure. Thus, the appearance of such phrases in various places throughout the text are not necessarily referring to the same embodiment of the present disclosure. Furthermore, the particular features, configurations, compositions, or characteristics may be combined in any suitable manner in one or more embodiments.

[0130] The words "preferred" and "preferably" refer to embodiments of the present disclosure that may provide certain benefits in certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. In addition, the recitation of one or more preferred embodiments does not mean that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the present disclosure.

Claims

1. A method comprising: obtaining, using a pacing device, rate modification information including at least one physical characteristic of the patient; as well as A pacing rate lower limit of the pacing device is determined based on the obtained rate modification information, wherein the pacing rate lower limit is used by the pacing device to initiate pacing in response to the patient's intrinsic rate being less than the pacing rate lower limit.

2. A system comprising: A computing device comprising one or more processors and configured to: obtaining, using a pacing device, rate modification information including at least one physical characteristic of the patient; as well as A pacing rate lower limit of the pacing device is determined based on the obtained rate modification information, wherein the pacing rate lower limit is used by the pacing device to initiate pacing in response to the patient's intrinsic rate being less than the pacing rate lower limit.

3. An implantable medical device comprising: one or more electrodes for delivering cardiac pacing therapy to a patient's heart and sensing electrical activity from the patient's heart; and A computing device operably coupled to the one or more electrodes and comprising one or more processors, the computing device configured to: monitoring the patient's intrinsic heart rate using the one or more electrodes; delivering pacing therapy to the patient's heart in response to the patient's intrinsic rate being less than a lower pacing rate limit; obtaining, using a pacing device, rate modification information including at least one physical characteristic of the patient; as well as A lower pacing rate limit of the pacing device is determined based on the obtained rate modification information.

4. The method of claim 1, the system of claim 2, or the device of claim 3, wherein the at least one physical characteristic comprises one or more of height, gender, age, body mass index (BMI), body surface area, physical fitness level, and activity level.

5. The method, system or device of any one of claims 1 to 4, wherein the rate modification information further comprises at least one pathology, wherein the at least one pathology comprises diastolic dysfunction / heart failure with preserved ejection fraction.

6. The method, system or device of any one of claims 1 to 5, wherein the rate modification information further comprises at least one pathology, wherein the at least one pathology comprises one or more of systolic dysfunction, chronotropic insufficiency, worsening heart failure and comorbidity.

7. A method, system or device according to any one of claims 1 to 6, wherein the rate modification information also includes at least one diagnostic parameter, wherein the at least one diagnostic parameter includes one or more of ventricular contractility, ventricular stiffness, pulse transit time, resting heart rate, nocturnal heart rate, arrhythmia burden, target pacing burden, heart rate recovery, impedance, fluid overload, edema, respiratory rate, maximum heart rate, ejection fraction, left ventricular pressure, systemic blood pressure, pulmonary artery pressure, blood oxygen, and the presence or concentration of serum biomarkers.

8. The method, system or device of claim 7, wherein obtaining rate modification information comprises monitoring the at least one diagnostic parameter of the patient using the pacing device.

9. A method, system or device according to any one of claims 1 to 8, wherein the rate modification information also includes at least one device configuration, wherein the at least one device configuration includes one or more of a ventricular pacing electrode position, an atrial pacing electrode position and a pacing therapy type.

10. A method, system or device according to any one of claims 1 to 9, wherein the rate modification information also includes patient reported information, wherein the patient reported information includes one or more of energy level, peripheral edema, desired activity performance, and pacing-related symptoms.

11. The method, system or device of any one of claims 1 to 10, wherein the rate modification information further comprises patient reported information, wherein the patient reported information is obtained from a mobile computing device.

12. The method or system of any one of claims 1 to 2 and 4 to 11, wherein the method further comprises or the computing device is further configured to perform configuring the pacing device with the pacing rate lower limit.

13. The method, system or apparatus of any one of claims 1 to 12, wherein obtaining rate modification information comprises obtaining the rate modification information from an electronic medical record system.

14. The method according to any one of claims 1 and 4 to 10, wherein determining a lower pacing rate limit of the pacing device based on the obtained rate modification information is performed by the pacing device.

15. A method or system according to any one of claims 1 to 2 and 4 to 14, wherein determining the pacing rate lower limit of the pacing device based on the obtained rate modification information is performed by a remote computing system communicatively coupled to the pacing device.

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