Cardiac pacemaker

Abstract

The invention relates to a leadless endocardial or intravascular cardiac pacemaker. The cardiac pacemaker has a housing (1) with an anchoring device (2). In the housing are a sensor unit (3), a control unit (4), a stimulation impulse generator (5), an impulse delivery means (6), and an energy storage unit (7). The leadless endocardial or intravascular cardiac pacemaker is also configured to communicate with an external unit (8). The leadless endocardial or intravascular cardiac pacemaker is characterised in that more than 50% of the capacity of the energy storage unit (7) is available for generating the impulses in the stimulation impulse generator (5).

Description

[0001] pacemaker

[0002] Description

[0003] The invention relates to a leadless endocardial or intravascular pacemaker, characterized in that it comprises a sensor unit, a control unit, a stimulation pulse generator, a pulse transmitter, and an energy storage unit in a housing with an anchoring unit. The pacemaker is configured for communication with an external unit.

[0004] The first pacemaker fully and permanently embedded in the human body was implanted in 1958. The pacemaker concept developed at that time consists of a main component, also called a "unit," which is implanted in a pocket infraclavicularly. This unit contains a battery, a control unit, and connectors for leads. These leads are advanced through venous access to the right heart and anchored there in the right atrium and / or right ventricle. The leads serve both as sensors to detect cardiac activity and as electrodes to deliver the impulse generated by the control unit's pulse generator to the myocardium. This basic concept was further developed through numerous improvements in the following decades, but remained essentially unchanged.

[0005] Problem areas of this conventional pacemaker therapy are hematomas and infections in the area of ​​the “aggregate” and dislocations, fractures and infections in the area of ​​the leads.

[0006] To counteract these weaknesses, leadless pacemakers were developed at the beginning of the 21st century. EP 1 714670 A1 describes a leadless endocardial or intravascular pacemaker with a sealed housing. This housing contains a battery, a pacemaker controller connected to the battery, and a stimulation pulse generator. Furthermore, the pacemaker described therein is characterized by the fact that the housing is elongated and has a length of less than 70 mm and a cross-sectional area of ​​less than 100 mm. 2It carries at least two electrodes, each facing outward and having an electrically conductive surface. The electrodes are therefore designed as stimulation electrodes. They are at least temporarily electrically connected to the stimulation pulse generator via an electrical connection arranged inside the housing.

[0007] The key development of this pacemaker concept according to EP 1 714670 A1 is to house all components of a conventional pacemaker, except for the leads and connectors, in a single, hermetically sealed housing. This reduction in size of the pacemaker, achieved through miniaturization of the components, makes it possible to implant it entirely in the right heart.

[0008] The first leadless endocardial pacemaker was implanted in a patient in 2013.

[0009] In the years that followed, the concept of the leadless endocardial pacemaker was further improved through numerous developments. Currently, approximately one million of these pacemakers are implanted worldwide, demonstrating the success of this new therapy. However, the concept of the leadless endocardial pacemaker has weaknesses that can be overcome through further developments.

[0010] The main limitation of currently implantable leadless endocardial or intravascular pacemakers is the limited available battery capacity.

[0011] Because leadless endocardial pacemakers are inserted into the right heart via veins and anchored there, the dimensions of the pacemaker housing cannot be arbitrarily increased to accommodate, for example, a larger energy storage unit / battery with a correspondingly higher capacity. Therefore, a longer operating life of the leadless endocardial pacemaker can only be achieved by increasing the energy storage density of lithium-ion batteries and more effective use of the available battery capacity.

[0012] A longer battery life is particularly important for leadless pacemakers implanted intracardially or intravascularly, as retrieving an implant with a depleted energy storage unit / battery carries certain risks. This risk increases with the length of time the implant remains in the patient's body, as over time, the entire casing of the implanted pacemaker is usually overgrown by the cardiac endothelium, and the implant is thus virtually encapsulated within the myocardium.

[0013] Furthermore, approximately 20% of patients fitted with a leadless endocardial pacemaker develop cardiomyopathy due to the unphysiological ventricular pacing situation in the right ventricle, which can lead to heart failure. Therefore, pacing that utilizes parts of the heart's natural conduction system (so-called conduction system pacing) is desirable. Direct HIS bundle pacing is considered the "most ideal" method of ventricular pacing with a pacemaker. However, the electrical impulse required for this requires more energy than direct ventricular pacing, placing greater strain on the pacemaker's energy storage unit / battery.

[0014] In current leadless endocardial pacemakers, half of the battery capacity (typically 120 mA) is consumed by the sensor for detecting cardiac activity, the control unit, and the pacing pulse generator. The remaining 50% is delivered as pulse energy to the myocardium via the lead.

[0015] The object of the invention is to provide a leadless endocardial or intravascular pacemaker that more effectively utilizes the capacity of the energy storage unit built into the pacemaker housing. This should extend its service life. Depending on the patient's age and the time of implantation, the goal is to achieve operating times that make the removal of an endocardially implanted pacemaker with a spent energy storage unit unnecessary. Furthermore, the object of the invention is to provide a pacemaker that can generate a stronger pulse via the stimulation pulse generator. The goal is to enable physiological stimulation of the heart via the HIS bundle. By using the invention in this way, the cardiomyopathies that would be expected with non-physiological pulse positioning can be reduced or even completely avoided.This object is achieved according to the invention in that more than 50% of the capacity of the energy storage unit is available for generating the pulses in the stimulation pulse generator.

[0016] This means that less than 50% of the capacity of the energy storage unit is required for the energy consumption of the control unit, the sensor, the pre-processing unit, and the post-processing unit.

[0017] In conventional leadless endocardial or intravascular pacemakers, approximately 50% of the available battery capacity is consumed by the pacemaker's sensor and control electronics, so that only approximately 50% is available for generating the stimulation pulses.

[0018] According to the invention, this ratio of 50% for the internal consumption of the sensor and control electronics of a pacemaker is shifted by the invention such that the sensor and control unit require significantly less electricity to operate, and therefore a larger proportion of the existing capacity of the energy storage unit is available for pulse generation. The battery capacity thus gained can either be used to deliver normal-strength pulses or to generate stronger pulses. In the first case, the pacemaker's operating time is extended; in the second case, the pacemaker's operating time is unlikely to be extended; however, the higher pulse strength enables cardiac stimulation via parts of the physiological conduction system (HIS bundle stimulation).The control unit of the leadless endocardial or intravascular pacemaker includes a preprocessing unit. This unit modulates the signals provided by the sensor unit.

[0019] By modulating the signals, certain properties of the carrier signal are changed in such a way that the information content of the signal is encoded for transmission to the control unit and for storage and processing in the control unit.

[0020] For this purpose, the carrier signal can be in the form of a high-frequency sine wave or a continuous signal. The frequency, current, and / or voltage of the carrier signal are determined to ensure particularly fast and reliable transmission over the transmission channel.

[0021] Modulation, for example, changes one or more properties of the signal depending on the properties of the sensor unit. For this purpose, the amplitude and / or frequency and / or phase are preferably modulated.

[0022] The control unit of the leadless endocardial or intravascular pacemaker also includes a post-processing unit. This unit modulates the signals sent from the control unit to the stimulation pulse generator.

[0023] Furthermore, the leadless endocardial or intravascular pacemaker presented here includes an external unit for communication or programming the control unit. The external unit for the control unit is a component used in many technical systems and devices to develop, edit, or update the software or programmed logic that enables the control of the system. The function of such an external unit is to enable developers to create and transmit the desired programs or instructions for the control unit. The basic functions and features are described below:

[0024] For example, adjustments can be saved in a version chronology in the external unit. Furthermore, the control algorithms for the control unit can be adapted to the patient's current needs.

[0025] In a variant of the invention, the code adaptations can additionally be transferred to a development platform via various interfaces such as USB, Ethernet or serial connections.

[0026] The external unit can also include functions for versioning and storing code, for example.

[0027] In one embodiment of the invention, the external unit of the control unit serves to carry out firmware updates, which are made available, for example, via external interfaces.

[0028] For example, the external unit can also implement security mechanisms and access controls to ensure only authorized access to the control unit.

[0029] In one variant of the invention, the control unit of the leadless endocardial or intravascular pacemaker enables adaptive learning. This allows, for example, an adapted response to changing physical stress on the patient.

[0030] The sensor unit of the leadless endocardial or intravascular pacemaker comprises, for example, at least a combination of one or more memristors and one or more piezoelectric elements.

[0031] In one example, the control unit of the leadless endocardial or intravascular pacemaker comprises a system and / or structure of programmable resistance elements. These elements may, for example, be memristors.

[0032] In one embodiment of the invention, the control unit of the leadless endocardial or intravascular pacemaker comprises one or a plurality of memristors.

[0033] In one embodiment of the invention, the control unit of the leadless endocardial or intravascular pacemaker is designed as a neuromorphic machine. This can be based on a structure of programmable resistance elements, preferably memristors.

[0034] Neuromorphic technology can enable the control unit of a leadless endocardial or intravascular pacemaker to learn autonomously and thus better adapt to the patient's needs, thus always achieving the most physiological stimulation possible. A memristor is an electrical component designed as a type of nonlinear resistive element. Memristors have the special property of being able to store information about the electrical charge or current flowing through them and retain this information even when the power supply is interrupted. This behavior has the advantage of forming a kind of synaptic memory.

[0035] Memristors remain in a specific state and store information via the electrical charge introduced into them. This makes them a non-volatile memory in a leadless endocardial or intravascular pacemaker.

[0036] The electrical conductivity of a memristor does not depend linearly on the applied voltage or current. Rather, it varies depending on the previous state, in particular the number and intensity of the input systems, e.g., the signals from the sensor unit.

[0037] For example, the control unit of a leadless endocardial or intravascular pacemaker using neuromorphic technology can be implemented as an in-memory computing architecture. In-memory computing is an alternative to the von Neumann architecture.

[0038] The neuromorphic architecture of the control unit of the leadless endocardial or intravascular pacemaker is particularly energy-efficient, allowing the energy storage unit's capacity to be used primarily for stimulation pulses. The control unit of the leadless endocardial or intravascular pacemaker can process data in an event-driven and / or spiking manner, comparable to biological neural networks. The module's control unit reacts in real time to the patient's changing physiological conditions.

[0039] In one embodiment, the control unit of the leadless endocardial or intravascular pacemaker is a neuromorphic device that uses memristors as synaptic elements. These memristors exhibit adaptive learning capabilities and synaptic plasticity, which also allow adaptation to different physiological states of the patient.

[0040] The memristive neuromorphic control unit of the leadless endocardial or intravascular pacemaker adapts in real time to the changing physiological conditions of the patient.

[0041] In a variant of the invention, the control unit is integrated into the sensor unit.

[0042] The neuromorphic architecture of the control unit of the leadless endocardial or intravascular pacemaker is particularly energy-efficient, so that the capacity of the energy storage unit is only minimally burdened by the control unit's own power consumption.

[0043] The housing of the leadless endocardial or intravascular pacemaker is dimensioned so that it can be advanced to the right heart via standard venous access without causing any disruption to the heart's physiological function. Furthermore, the housing features anchoring devices that allow the leadless endocardial or intravascular pacemaker to be securely anchored in the myocardium or a larger blood vessel. These anchoring devices can be designed using state-of-the-art technology.

[0044] The sensor unit of the leadless endocardial or intravascular pacemaker can be implemented as a thermal sensor and / or an acceleration sensor and / or a vibration sensor according to the state of the art. The signals generated by these sensor variants are modulated in a preprocessing unit so that they can be processed by the control unit.

[0045] The pulse generator of the leadless endocardial or intravascular pacemaker is equipped with a state-of-the-art steroid-releasing electrode. It has an electrically conductive surface and is connected to the pacing pulse generator via an electrical connection.

[0046] In an alternative embodiment, the control unit of the leadless endocardial or intravascular pacemaker may comprise a neuromorphic processor.

[0047] The neuromorphic processor processes analog and / or digital signals (ASP / DSP) in the form of spiking neutral networks (SNN), mimicking biological neural networks to detect, classify, and interpret patterns relevant to cardiac activity.

[0048] Neuromorphic processors, similar to memristors, exhibit extremely low power consumption, enabling long-term continuous active pattern recognition. They are therefore also suitable for ensuring that more than 50% of the energy storage unit's capacity is available for generating the pulses in the stimulation pulse generator. Furthermore, the data processing speed of neuromorphic processors is significantly increased compared to conventional processors. This makes a neuromorphic processor particularly advantageous in latency-critical applications, such as those found in cardiac pacemakers.

[0049] Finally, neuromorphic processors are significantly smaller than conventional processors while offering the same performance. This property is particularly advantageous for use in leadless endocardial or intravascular pacemakers, as the housing dimensions are strictly limited due to physiological conditions. The space gained by reducing the size of the control unit can be used to increase the size of the energy storage unit accordingly, thereby extending the pacemaker's operating life.

[0050] Neuromorphic processors are optimized for detecting and processing signals from thermal sensors and / or acceleration sensors and / or vibration sensors. In a preferred embodiment, the leadless endocardial or intravascular pacemaker disclosed here uses neuromorphic processors optimized for processing vibration signals, e.g., acoustic signals.

[0051] In a preferred embodiment, at least one input module, at least one threshold calculation module and at least one normalization module are integrated into the neuromorphic processor of the control unit.

[0052] The input module captures input signals and converts them into spiked signals. The threshold calculation module provides one or more threshold parameters based on the average values ​​of the received spike patterns within a defined range.

[0053] The normalization module generates signal spikes at the output using one or more integrate-and-fire (IAF) counters. Once a threshold parameter is reached, the IAF counter is reset.

[0054] The threshold calculation module allows the threshold parameter(s) to be dynamically adjusted based on the variability of the input spikes within a defined range. This allows the normalization module to adapt to different signal conditions, such as those that may arise from different physiological stress states.

[0055] Neuromorphic processors are designed to monitor multiple parallel channels, each with different frequencies. This extended frequency range allows for the precise detection of abnormal conditions that deviate from the pattern recognition of normal cardiac activity and the early initiation of appropriate corrective measures.

[0056] The neuromorphic processor operates in an event-driven manner and processes data asynchronously. This effectively reduces power consumption, allowing the electrical energy stored in the energy storage unit to be used primarily to generate pulses via the stimulation pulse generator.

[0057] The control unit's reaction speed is then significantly increased through the use of a neuromorphic processor. The latency with which it can react after the detection of a non-physiological event is correspondingly significantly reduced. Preferably, a leaky integrate-and-fire (LIF) model is implemented to process incoming signals by generating spike outputs when certain thresholds are reached.

[0058] The leadless endocardial or intravascular pacemaker described here enables stimulation of the heart according to established, conventional therapy, but with the advantage of a longer device life and the resulting benefits for the patient, which were demonstrated in the appraisal of this invention.

[0059] Furthermore, it is also suitable for pacing via the HIS bundle. Utilizing part of the heart's natural conduction system for cardiac pacing offers further advantages for the patient, which were also highlighted in the appraisal of this invention.

[0060] Further features of the invention will become apparent from the description of an embodiment with reference to a drawing and from the drawing itself.

[0061] This shows

[0062] Fig. 1 a block diagram of a probeless endocardial or intravascular

[0063] Pacemaker, Fig. 2 a schematic representation of the cardiac anatomy with the components of physiological conduction and an alternative placement of the leadless endocardial or intravascular pacemaker.

[0064] List of reference symbols:

[0065] (1) Housing

[0066] (2) Anchoring device

[0067] (3) Sensor unit

[0068] (4) Control unit

[0069] (5) Pacing pulse generator

[0070] (6) Pulse generator

[0071] (7) Energy storage unit

[0072] (8) external unit

[0073] (9) Preprocessing unit

[0074] (10) Post-processing unit

[0075] (11 ) AV node

[0076] (12) left atrium

[0077] (13) HIS bundle

[0078] (14) left ventricle

[0079] (15) Tawara leg left

[0080] (16) Purkinje fibers

[0081] (17) Tawara leg right

[0082] (18) right ventricle

[0083] (19) right atrium

[0084] (20) Internodial bundle

[0085] (21 ) Sinus node

[0086] Fig. 1 shows a schematic representation in the form of a block diagram of a leadless endocardial or intravascular pacemaker.

[0087] In the illustrated embodiment, the pacemaker comprises a cylindrical housing 1 which is elongated and has a length of less than 40 mm and a cross-sectional area of ​​less than 40 mm 2 has.

[0088] A pulse generator 6 is arranged on one of the two base surfaces of the cylinder, with its electrically conductive and steroid-releasing surface facing outwards.

[0089] At the end of the cylindrical housing 1, at which the pulse generator 6 is arranged, there is also an anchoring device 2 of the leadless endocardial or intravascular pacemaker.

[0090] The pulse generator 6 is electrically connected to a stimulation pulse generator 5 inside the housing 1.

[0091] The stimulation pulse generator 5 receives its signals from a post-processing unit 10. The post-processing unit 10 modulates the signals generated by the control unit (4) so ​​that the stimulation pulse generator 5 can be controlled appropriately. A control unit 4 processes the signals generated by a pre-processing unit 9. These signals are the modulation of signals sent from a sensor unit 3 to a pre-processing unit 9.

[0092] The sensor unit 3 can be designed as a temperature sensor and / or as an acceleration sensor and / or as a vibration sensor.

[0093] The components sensor unit 3, pre-processing unit 9, control unit 4 and post-processing unit 10 can be designed as an integrated component.

[0094] An energy storage unit 7 is arranged on the side of the cylindrical housing 1 opposite the pulse generator 6. Electrical connections exist to the components installed in the housing 1.

[0095] An external unit 8 is located outside the leadless endocardial or intravascular pacemaker. The external unit 8 enables communication with the control unit 4 of the leadless endocardial or intravascular pacemaker via various wireless interfaces.

[0096] Fig. 2 shows a schematic representation of the relevant cardiac anatomy with the components of physiological conduction in the heart.

[0097] It also shows the alternative placement of leadless endocardial or intravascular pacemakers.

[0098] Placement of the leadless endocardial or intravascular pacemaker in the area of ​​position A corresponds to conventional therapy with direct stimulation of the myocardium of the right ventricle. Placement of the leadless endocardial or intravascular pacemaker in the area of ​​position B enables stimulation of the HIS bundle. The HIS bundle belongs to the physiological part of the excitation system of the

[0099] Heart. The stimulation impulse generated there by a leadless endocardial or intravascular pacemaker is transmitted physiologically via the two bundle branches of Tawara and the subsequent Purkinje fibers.

Claims

pacemaker Claims 1 . Leadless endocardial or intravascular pacemaker with a housing (1) with an anchoring device (2), a sensor unit (3), a control unit (4), a stimulation pulse generator (5), a pulse emitter (6), an energy storage unit (7), wherein the pacemaker is designed to communicate with an external unit (8), characterized in that more than 50% of the capacity of the energy storage unit (7) is available for generating the pulses in the stimulation pulse generator (5).

2. Pacemaker according to claim 1, characterized in that less than 50% of the capacity of the energy storage unit (7) is required for the energy consumption of the control unit (4), the sensor unit (3) and the pre-processing unit (9) and the post-processing unit (10).

3. Pacemaker according to claim 1 or 2, characterized in that the pacemaker comprises a pre-processing unit (9) for modulating the signals from the sensor unit (3) to the control unit (4) and a post-processing unit (10) for modulating signals from the control unit (4) to the stimulation pulse generator (5).

4. Pacemaker according to one of claims 1 to 3, characterized in that the external unit (8) is arranged for programming the control unit (4).

5. Pacemaker according to one of claims 1 to 4, characterized in that the control unit (4) is configured for adaptive learning.

6. Pacemaker according to one of claims 1 to 5, characterized in that the control unit (4) comprises a structure of programmable resistance elements.

7. Pacemaker according to one of claims 1 to 6, characterized in that the control unit (4) is integrated into the sensor unit (3).

8. Pacemaker according to one of claims 1 to 7, characterized in that the housing (1) is elongated and has a length of less than 40 mm and a cross-sectional area of ​​less than 40 mm 2 owns.

9. Pacemaker according to one of claims 1 to 8, characterized in that the sensor unit (3) comprises at least one thermal sensor and / or at least one acceleration sensor and / or at least one vibration sensor.

10. A pacemaker according to any one of claims 1 to 9, characterized in that the pulse generator (6) has an outwardly directed, electrically conductive surface and is designed as a stimulation electrode. The pulse generator is then at least temporarily electrically connected to the stimulation pulse generator (5) via an electrical connection arranged inside the housing.

11. Pacemaker according to one of claims 1 to 10, characterized in that the control unit (4) comprises a neuromorphic processor.

12. Pacemaker according to claim 11, characterized in that the neuromorphic processor is optimized for the detection and processing of signals from thermal sensors and / or signals from acceleration sensors and / or signals from vibration sensors.

13. A pacemaker according to claim 11 or 12, characterized in that the neuromorphic processor comprises at least one input module, at least one threshold calculation module and at least one normalization module.

14. A pacemaker according to claim 13, characterized in that the threshold calculation module is configured to adapt the threshold parameters based on the variability of the input spikes within a defined range.

15. A pacemaker according to any one of claims 11 to 14, characterized in that the neuromorphic processor is designed to process the different input signals from the sensors, e.g., the frequency signals of a vibration sensor, on a plurality of parallel channels.

16. A pacemaker according to any one of claims 11 to 15, characterized in that the neuromorphic processor is configured for event-driven and asynchronous processing of data.

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