Cardiac pacing device and dual chamber pacing system

Abstract

The present invention provides a cardiac pacing device (100) for implantation in a patient's heart, the cardiac pacing device (100) comprising a processing unit (120) for controlling a pacing signal generator (124) and further comprising a detector (126) configured to measure a time-dependent signal of intrinsic atrial activity, the processing unit (120) being configured to detect the presence and absence of intrinsic atrial events (Ap, Ap) within a cardiac cycle based on the measured signal of atrial activity within each cardiac cycle received from the detector (126), and the processing unit controlling the pacing signal generator (124) to generate electrical signals (Ap, Ap) based on the presence and absence of intrinsic atrial events (Ap). * Additionally, systems including such first and second cardiac pacing devices and methods of operating each are described.

Description

[Technical field]

[0001] The present invention is generally directed to cardiac pacing devices, methods of operating such devices, systems comprising a first cardiac pacing device and a second cardiac pacing device and methods of operating such systems, computer program products and computer readable data carriers for each.

[0002] A cardiac pacing device, such as a cardiac pacemaker (or artificial pacemaker), is a medical device that generates electrical pulses delivered by electrodes connected to or affixed to the pacemaker to contract the myocardial chambers (i.e., atria and / or ventricles) and thus pump blood. By doing so, the device replaces and / or regulates the function of the heart's electrical conduction system. One purpose of a cardiac pacing device is to maintain an adequate heart rate because the heart's natural pacemaker is not fast enough or a block exists in the heart's electrical conduction system. Modern pacemakers are externally programmable, allowing a healthcare practitioner (HCP), such as a clinician, to select the optimal pacing mode for an individual patient.

[0003] A conventional pacemaker comprises a control and generator device with a processing unit and power source external to the patient's heart and electrodes implanted within the heart muscle. The electrodes are connected to the device via leads and a header located on the device. In most cases, the device is implanted subcutaneously in the left or right shoulder area on the front of the chest. An implantable cardiac pacemaker (also known as an implantable leadless pacemaker - ILP) is a miniature pacemaker that is implanted entirely within the patient's ventricle (V) or atrium (A). Alternative or additional functions of conventional or intracardiac pacemakers include providing other electrical or electromagnetic signals to the heart or its surrounding tissues and sensing electrical or electromagnetic signals (e.g., signals from an electrical depolarization field) or other physiological parameters of the heart and / or its surrounding tissues, such as intrinsic (i.e., the heart's natural) atrial contractions or intrinsic (i.e., the heart's natural) ventricular contractions. Due to the very limited device size, ILPs have small battery capacities.

[0004] The ILP can operate in a VDD pacing mode (i.e., a pacing mode in which the ventricles are stimulated according to the intrinsic atrial signal and AV conduction monitoring). In the VDD mode, the pacemaker synchronizes ventricular pacing with the intrinsic atrial timing by sensing when an atrial contraction (i.e., the intrinsic atrial signal) occurs. The ILP, implanted in the right ventricle, can detect atrial contraction information, but with less reliability and accuracy than a dual-chamber conventional pacemaker with leads in the right atrium as well as the right ventricle.

[0005] However, there are situations where a patient suffers from various cardiac arrhythmias that require different cardiac therapies. In such cases, a system of devices comprising at least two cardiac pacing devices or units may be implanted, and pacing may be provided in the atrium using a first device and in the ventricle using a second device.

[0006] U.S. Patent Application Publication No. 2016 / 0067490 discloses a dual-chamber leadless pacing system with at least one atrial pacing device and at least one ventricular pacing device. To adjust the pacing rate in such a system, signals are transmitted from the atrial pacing device to the ventricular pacing device or from the ventricular pacing device to the atrial pacing device, and the pacing rate of each is adjusted based on the received signals. To this end, a separate communication unit of the atrial or ventricular pacing device is provided that includes appropriate hardware (e.g., an antenna), firmware, software, or any combination thereof and consumes energy while communicating with each other pacing device.

[0007] As mentioned above, the new dual chamber technology brings with it several challenges. Due to the size limitations of intracardiac devices, the demands on energy consumption and the use of electronic components are dramatically increased. Furthermore, intracardiac devices intended to be implanted in the atria of the heart require special design considerations. The volume available for device placement is smaller compared to the ventricles, and the atrial tissue is extremely thin compared to the ventricles. Furthermore, communication in dual chamber systems can face compatibility issues, especially when different system components are provided by various suppliers / manufacturers, or when parts of the intracardiac devices (batteries, communication units) are replaced during the service life of each device (e.g., in the case of box change when the battery is depleted).

[0008] Thus, there is a need for a cardiac pacing device that better addresses the requirements for energy consumption, fixation to cardiac tissue, and available space, and ensures compatibility between system components.

[0009] The above problem is solved by a cardiac pacing device having the features of claim 1, a system comprising a first cardiac pacing device and a second cardiac pacing device having the features of claim 5, methods for operating each such cardiac pacing device or system having the features of claims 8 and 12, respectively, as well as a computer program product having the features of claim 14 and a computer-readable data carrier having the features of claim 15.

[0010] In particular, the above problem is solved by a cardiac pacing device for implantation in a patient's heart, the cardiac pacing device comprising a processing unit for controlling a pacing signal generator and a detector further configured to measure a time-dependent signal of intrinsic atrial activity. The processing unit is configured to detect the presence and absence of an intrinsic atrial event (i.e., an intrinsic atrial depolarization followed by an atrial contraction, a spontaneous p-wave) within a cardiac cycle based on the measured signal of atrial activity within each cardiac cycle received from the detector. Furthermore, the processing unit is configured to control the pacing signal generator to provide a first electrical signal in the absence of an intrinsic atrial event within each cardiac cycle and to provide a second electrical signal in the presence of an intrinsic atrial event within each cardiac cycle, the second electrical signal being different from the first electrical signal.

[0011] The cardiac pacing device defined above further comprises at least one electrode electrically connected to the pacing signal generator, for example via a header, where the at least one electrode, for example two electrodes, is implanted adjacent to the cardiac tissue or in the cardiac tissue to be paced after implantation. The first and second electrical signals generated by the pacing signal generator are transmitted to the at least one electrode such that the first and second electrical signals are provided to the cardiac tissue adjacent to the at least one electrode. Thus, the pacing device stimulates the myocardium with the first electrical (pacing) signal if an intrinsic atrial signal is not detected within each actual cardiac cycle. In addition, the cardiac pacing signal generator provides a second electrical signal within each cardiac cycle, which is transmitted to the at least one electrode and provided to the heart by the at least one electrode. Thus, an electrical signal (for example, a stimulation signal) is provided within each cardiac cycle, either the first electrical signal for atrial pacing in the absence of atrial sensing, or the second electrical signal. A (modified) AAT mode is thereby achieved. The AAT mode of the pacemaker refers to a mode in which the paced and sensed chambers are also the atrial chambers, and the response to sensing is characterized as "triggered" indicating that an electrical pulse (e.g., stimulation) is provided once within each cardiac cycle. The pacing mode is characterized as "modified" because there are two different electrical signals provided, a first electrical signal and a second electrical signal, where the first electrical signal is expected to successfully capture the myocardium and the second electrical signal is expected not to capture the myocardium but to indicate to another device (a sensor or another cardiac pacing device) that there was an intrinsic atrial event within each cardiac cycle. The first and second electrical signals may be detected by a sensor or another cardiac pacing device, whereby information regarding the presence or absence of an intrinsic atrial signal may be detected, with the absence of an intrinsic atrial signal resulting in an electrical stimulation that captures the myocardium and the presence of an intrinsic atrial signal resulting in a triggered stimulation / electrical signal.Thus, a separate communication channel for transmitting such information does not necessarily lead to a reduction in size and energy consumption of the cardiac pacing device such that the life span of the cardiac pacing device is increased as compared to the prior art described above. Furthermore, since the cardiac electrical signals can be detected by different detectors, compatibility issues associated with a separate communication channel for transmitting such information no longer exist.

[0012] The cardiac pacing device may be a defibrillator with pacing capabilities, or any other device with pacing capabilities, or an ILP, each of the examples having the general structure and functions as described above and below.

[0013] If the cardiac pacing device is an ILP, one electrode can be located at a distal end of the ILP, proximal to a fixation member where the ILP is fixed in the tissue of the patient's heart, e.g., the internal tissue of a ventricle, and a second electrode can be located at a proximal end of the ILP, or a portion of the ILP housing can function, for example, as a counter electrode.

[0014] In the context of the present invention, a processing unit is generally considered to be a functional unit of a cardiac pacing device that interprets and executes instructions, including a command control unit and an arithmetic logic unit. The processing unit may comprise a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a discrete logic circuit, or any combination thereof. Alternatively or additionally, the processing unit may be realized using integrated dedicated hardware logic circuits due to small size and extreme power limitations, particularly in the case of ILP. Furthermore, the processing unit may be configured to process signal data received from the detector, particularly the measured signal of atrial activity. The processing unit may further comprise a counter and a clock. The counter may be used to count the clock signals of the clock. The counter may be started at each sensed atrial or ventricular contraction and may count the clock number signals until the next atrial or ventricular contraction occurs or atrial pacing is provided by the pacing signal generator.

[0015] In one embodiment of the cardiac pacing device, the first electrical signal is configured to effectively pace the myocardium based on at least one predetermined treatment parameter stored in a data memory connected to the pacing signal generator, and the second electrical signal has a lower amplitude and / or a lower signal width (signal duration) and / or a different signal morphology. The initiation time of the second electrical signal is related to the intrinsic contraction event of the ventricle. Thus, the cardiac pacing device may stimulate, for example, in the atrium of the patient's heart with different amplitudes (e.g., the actual "pacing amplitude" to capture the myocardium - the first electrical signal and a significantly lower "trigger amplitude" - the second electrical signal that only serves to support far-field sensing), reducing the longevity impact on the device due to AAT stimulation. For example, the amplitude of the second electrical signal is at least 20% lower, preferably at least 40% lower than the amplitude of the first electrical signal. The amplitude of the second electrical signal may be, for example, between 0.01V and 2V. Therefore, alternatively or additionally, the signal width of the second electrical signal may be at least 20% lower or at least 20% higher than the signal width of the first electrical signal, and the pulse width of the second electrical signal may be 0.01 ms to 0.25 ms, preferably 0.01 ms to 0.1 ms. Also, as shown below, the first electrical signal and / or the second electrical signal may be pulse signals, in which case the aforementioned signal width is considered as a pulse width. Additionally or alternatively, the signal forms of the first electrical signal and the second electrical signal may be different. For example, the first electrical signal may be one pulse and the second electrical signal may be at least two pulses (e.g., double or triple pulse), and / or vice versa. In another embodiment, the second electrical signal may be delivered by the pacing signal generator with a predetermined (short) delay after the onset of the sensed intrinsic atrial event. For example, the second electrical signal is delivered with a delay of at least 0.1 ms after detection of a sensed intrinsic atrial event, thereby ensuring that the second electrical signal is detected in a timely manner for ventricular pacing.This delay should not exceed 100 ms so that AV sequential timing is still guaranteed and ventricular paces are still delivered during the atrial refractory period.

[0016] In one embodiment of the cardiac pacing device, the first electrical signal of the cardiac pacing signal is a first pulse signal, and the second electrical signal is a second pulse signal, for example, the second electrical signal is a pulse signal consisting of multiple pulses provided in succession. It is generally well known to use pulses (or pulse signals) to pace the myocardium. However, according to the present invention, the pacing signal generator provides different types of pacing signals that can be distinguished by respective detectors or processing units, thereby transmitting information according to the actual state of the actual intrinsic atrial activity. For example, the first pulse signal and the second pulse signal may be rectangular pulses, cosine squared pulses, Gaussian pulses, etc. For the pulsed first and second signals, the above-mentioned differences in signal parameters may be applied similarly.

[0017] In one embodiment of the cardiac pacing device, the detector is configured to capture time-dependent electromagnetic and / or electrical and / or acoustic signals of atrial activity and, if applicable, ventricular activity. For example, the cardiac pacing device detects time-dependent electrical depolarization and repolarization field signals, such as an electrocardiogram (ECG) or IEGM (intracardiac electrogram), in the patient's heart, for example using at least one electrode, for example at least one electrode in the atrium of the patient's heart (i.e., an atrial IEGM), for example a high-resolution IEGM. The ECG or IEGM signal reflects and includes, for example, heart rate, PR interval, QT interval, ST interval, P-wave and T-wave duration. From signals reflecting cardiac activity, particularly atrial activity, the detector can derive electrical signals, such as electrical signals associated with the contraction of one of the atria (hereinafter intrinsic atrial signal) and electrical signals associated with the contraction of the ventricles (hereinafter intrinsic ventricular signal). In the case of an ILP located in the ventricle, the intrinsic atrial signal can be a far-field signal. The detector may further be configured to distinguish between intrinsic atrial signals and intrinsic ventricular signals. Moreover, the detector of the cardiac pacing device further senses a pacing signal (e.g., its onset time location and its duration as well as its rate or frequency) from another cardiac pacing device. These detected time-dependent signals may be filtered and / or amplified and transmitted to the processing unit. The processing unit may then detect whether an intrinsic atrial event is present from the received signal based on the presence or absence of this signal, e.g., a spontaneous p-wave in the atrial IEGM. If there is no spontaneous p-wave within a predetermined period from the start of each cardiac cycle, the processing unit triggers the pacing signal generator to directly provide a first electrical signal to pace the atrium without further delay. The time point of pacing depends on the period at which the pacing signal generator triggers pacing. If a spontaneous p-wave is detected, the processing unit triggers the pacing signal generator to provide a second electrical signal after a predetermined second period following the start of the spontaneous p-wave.

[0018] The cardiac pacing device may include a data memory, which may include any volatile, non-volatile, magnetic or electrical medium, such as a random access memory (RAM), a read only memory (ROM), a non-volatile RAM (NVRAM), a programmable ROM (e.g., EEPROM), a flash memory or any other memory device. The data memory stores the thresholds, values, parameters (e.g., parameters of the first, second and third signals) and conditions described above and below, which are required by the processing unit while processing the steps described above and below.

[0019] In addition to the above functions, the detector may include an accelerometer, a vibration sensor, an acoustic sensor (including ultrasound) and / or any other mechanical, electrical and / or magnetic sensor (i.e., a motion sensor) that can detect the actual activity of the patient depending on the time, for example, whether the patient is moving or not moving, for example, changing the body position / posture, sleeping, sitting, moving fast or slow including exercise. The detector collects the patient's activity signals and converts them into electrical signals. Furthermore, the cardiac pacing device may include a communication unit with a transceiver to exchange data with an external device such as a computer or a programmer.

[0020] Typically, the detector and / or processing unit may digitize, filter and / or smooth all or part of the detected or measured analog signals to reduce signal noise and / or select specific metrics. Some pre-processing steps may also be provided by the detector.

[0021] The units and components of the cardiac pacing device may be contained within a hermetically sealed housing.

[0022] The above problem is further solved by a system comprising the above cardiac pacing device as a first cardiac pacing device comprising a first processing unit, a first detector and a first pacing signal generator, the system further comprising a second cardiac pacing device comprising a second processing unit for controlling the second pacing signal generator and further comprising a second detector configured to measure a time-dependent signal of cardiac activity. Furthermore, the second processing unit is configured to identify a pacing signal from the cardiac activity signal received from the second detector and identify whether the pacing signal corresponds to the first electrical signal or the second electrical signal provided by the first cardiac pacing device, and the second processing unit is configured to control the second pacing signal generator to provide a third electrical signal when ventricular pacing is intended within each cardiac cycle, the third electrical signal achieving at least one predetermined signal parameter value depending on whether a pacing signal corresponding to the first electrical signal or the second electrical signal has been previously identified within the same cardiac cycle. The first cardiac pacing device and the second cardiac pacing device may comprise the modules, elements and units described above with respect to the cardiac pacing devices.

[0023] In one embodiment, the first cardiac pacing device may be an atrial ILP and the second cardiac pacing device may be a ventricular ILP. The first cardiac pacing device paces the atrium of the patient's heart with a first electrical signal or, if an intrinsic atrial event is detected, administers a second electrical signal as described above. A second detector of the second cardiac pacing device then detects each electrical signal close to an atrial stimulus triggered by the first electrical signal or caused by an internal process of the heart. Thus, when the second cardiac pacing device (e.g., operating in VDD mode) attempts to pace the ventricle, its second pacing signal generator provides a third electrical signal, the parameters of which depend on whether the first electrical signal or the second electrical signal was previously provided by the first cardiac pacing device. For example, the starting time of the third electrical signal depends on whether the first electrical signal or the second electrical signal was detected within each previous cardiac cycle (sensing compensation). Generally, the second electrical signal may occur later than the first electrical signal with respect to the intrinsic atrial event, and thus the time difference between the second electrical signal and the third electrical signal may be less than the time difference between the first electrical signal and the third electrical signal.

[0024] The first processing unit, the first pacing signal generator, the first detector, and if applicable, the first data memory are all electrically connected and contained within a housing of the first cardiac pacing device. The second processing unit, the second pacing signal generator, the second detector, and if applicable, the second data memory are all electrically connected and contained within a housing of the second cardiac pacing device. The first processing unit and / or the second processing unit can include hardware to support signal processing (e.g., scaling, filtering, rectification) of signals received from the first detector and the second detector, respectively.

[0025] In one embodiment, the second cardiac pacing device can operate in an inhibit mode (or ventricular demand mode) with respect to ventricular intrinsic events, e.g., VDD mode, which means that the second processing unit is further configured to detect the presence and absence of intrinsic ventricular events from the signal of cardiac activity received from the second detector, and provide a third electrical signal if the absence of an intrinsic ventricular event is detected within each cardiac cycle. The presence or absence of an intrinsic ventricular event is detected within a predetermined period of time from the start of each cardiac cycle, e.g., within a so-called AV delay. In one example, a system including the first cardiac pacing device and the second cardiac pacing device realizes dual chamber pacing, e.g., using a DDD mode, the first cardiac pacing device realizes an AAT mode, and the second cardiac pacing device realizes a VDD mode. In one embodiment, if support for intrinsic atrial event detection (p-wave detection) in the ventricular VDD device is not needed or desired at high atrial rates, the AAT mode may be further limited to a predetermined atrial rate, i.e., near an upper rate threshold for tracking. Alternatively, the second cardiac pacing device may operate in a VVI or VVI-R mode.

[0026] The above system has the advantages described above with respect to cardiac pacing devices. Moreover, it is advantageous that the first cardiac pacing device and the second cardiac pacing device do not need to be compatible with respect to their communication type and communication channel. Because the first and second signals are detectable from a different location than the atrium, i.e., the ventricle, better than the intrinsic atrial events (p-waves), the pacing of the second cardiac pacing device is more reliable, the devices can better remain synchronized with each other, and the pacing is adapted to the time of the atrial contraction.

[0027] The above problem is further solved by a method of operating a cardiac pacing device for implantation in a patient's heart, the cardiac pacing device comprising a processing unit for controlling a pacing signal generator and further comprising a detector for measuring a time-dependent signal of intrinsic atrial activity, the processing unit detects the presence and absence of an intrinsic atrial event within each cardiac cycle based on the measured signal of atrial activity within each cardiac cycle received from the detector, and the processing unit controls the pacing signal generator to provide a first electrical signal in the absence of an intrinsic atrial event within each cardiac cycle and to provide a second electrical signal in the presence of an intrinsic atrial event within each cardiac cycle, the second electrical signal being different from the first electrical signal.

[0028] In one embodiment of a method of operating a cardiac pacing device, a first electrical signal effectively paces the myocardium based on at least one predetermined treatment parameter, and a second electrical signal has a lower amplitude and / or a lower electrical signal width and / or a different electrical signal morphology compared to the first electrical signal.

[0029] In one embodiment of the method of operating a cardiac pacing device, the first electrical signal is a first pulse signal and the second electrical signal is a second pulse signal, e.g., the second electrical signal is a pulse signal consisting of multiple pulses provided in succession.

[0030] In one embodiment of a method of operating a cardiac pacing device, a detector captures time-dependent electromagnetic and / or electrical and / or acoustic signals of atrial activity.

[0031] The above problem is solved by a method of operating a system comprising the above mentioned cardiac pacing device as a first cardiac pacing device comprising a first processing unit, a first detector and a first pacing signal generator, the system further comprising a second cardiac pacing device, the second cardiac pacing device comprising a second processing unit for controlling the second pacing signal generator and further comprising a second detector for measuring a time-dependent signal of cardiac activity, the second processing unit deriving a pacing signal from the signal of cardiac activity received from the second detector. and a second processing unit controls a second pacing signal generator to provide a third electrical signal when ventricular pacing is intended within each cardiac cycle, the third electrical signal achieving at least one predetermined signal parameter value depending on whether a pacing signal corresponding to the first electrical signal or the second electrical signal has been previously identified within the same cardiac cycle.

[0032] In one embodiment of a method of operating the system, the second processing unit detects the presence and absence of intrinsic ventricular events from the cardiac activity signal received from the second detector and provides a third electrical signal if the absence of an intrinsic ventricular event is detected within each cardiac cycle.

[0033] The above-described embodiments of the method of operating the cardiac pacing device and system have the same advantages as those described above with respect to the cardiac pacing device and system. Each of the above-described embodiments of the cardiac pacing device and system can be similarly realized in a method of operating each of them. In this regard, reference is made to the above description of the cardiac pacing device and system.

[0034] Each of the above methods may be realized, for example, as a computer program including instructions, which when executed cause a processing unit (processor) to perform the steps of the above method (executed by the medical device, in particular on the processor) and enable the computer hardware to perform a computational or control function, either as a combination of computer instructions and data definitions specified above and below, or as syntactic units made up of declarations and statements or instructions necessary for the function, task or problem solution specified above and below, conforming to the rules of a particular programming language.

[0035] Further disclosed is a computer program product comprising instructions which, when executed by a processing unit, cause the processing unit to perform the steps of the method defined above. Accordingly, disclosed is a computer readable data carrier storing such a computer program product.

[0036] The invention will now be described in more detail with reference to the accompanying schematic drawings. [Brief description of the drawings]

[0037] [Figure 1] FIG. 1 illustrates a first embodiment of a system for atrial ILP and ventricular ILP in a cross-section of a patient's heart. [Diagram 2] FIG. 2 is a functional block diagram of the atrial ILP shown in FIG. 1. [Diagram 3] FIG. 2 is a functional block diagram of the ventricular ILP shown in FIG. 1. [Figure 4] FIG. 2 illustrates the IEGM signals over time for the atrial ILP and ventricular ILP of FIG. 1 when no intrinsic atrial event is detected and therefore an atrial pace is delivered. [Diagram 5] FIG. 2 illustrates the IEGM signals over time for the atrial ILP and ventricular ILP of FIG. 1 when an intrinsic atrial event is detected.

[0038] In the following, the present invention will be described with respect to a dual chamber ILP system including an atrial ILP and a ventricular ILP. The present invention may also be implemented in a system having a defibrillator or other device with cardiac pacing function. Furthermore, the atrial ILP is one embodiment of the cardiac pacing device described above.

[0039] FIGURE 1 shows an exemplary leadless pacing system 10 implanted in a heart 20 of a patient 30. The leadless pacing system 10 includes an atrial ILP 100 and a ventricular ILP 200. The atrial ILP 100 may be implanted in a right atrium 22 of the heart and configured to pace the atrium, sense intrinsic atrial depolarizations, and inhibit atrial pacing in response to a detected atrial depolarization. The ventricular ILP 200 may be implanted in a right ventricle 21 of the heart 20 and configured to monitor electrical activity of the heart 20, sense atrial and ventricular depolarizations (e.g., intrinsic atrial and ventricular depolarizations), and inhibit ventricular pacing in response to a detected ventricular depolarization. A programmer (not shown) can be used to program and retrieve data from the atrial ILP 100 and / or the ventricular ILP 200.

[0040] FIG. 2 shows a functional block diagram of an atrial ILP 100 configured to be implanted in the atrium 22 (FIG. 1). The atrial ILP 100 comprises, for example, a processing unit 120 with a clock, at least one counter for clock signals, a data memory 122, a pacing signal generator 124, a detector 126, and a power source 132. The atrial ILP 100 may also comprise, in one embodiment, a communication unit 128. The power source 132 may be electrically connected to one or more of the other components / units 120, 122, 124, 126, 128 (not shown in FIG. 2) and may include a battery, for example a rechargeable or non-rechargeable battery. The power source 132 supplies electrical energy to all units and components of the atrial ILP 100 (not explicitly shown in the figure for simplicity of the figure), in particular all units mentioned above, and is therefore electrically connected to these units and components. The units included in the atrial ILP 100 represent their respective functions. Similar or identical units and functions may be included in the atrial ILP 100. The units of the atrial ILP 100 of the present disclosure may include any discrete and / or integrated electronic circuit components implementing analog and / or digital circuits capable of generating the functions attributed to the units herein. For example, the units may include analog circuits, such as amplification circuits, filtering circuits, and / or other signal conditioning circuits. The units may also include digital circuits, such as combinational or sequential logic circuits, memory devices, and the like. The units may further be realized using integrated dedicated hardware logic circuits. The data memory 122 may include any volatile, non-volatile, magnetic, or electrical media described above. Furthermore, the processing unit 120 may include instructions that, when executed by one or more processing circuits, cause the units to perform various functions attributed to these units herein. The functions attributed to the units herein may be realized as one or more processors, hardware, firmware, software, or any combination thereof.The depiction of different features as units is intended to highlight different functional aspects and does not necessarily imply that such units must be realized by separate hardware or software components. Rather, functions associated with one or more units may be performed by separate hardware or software components or integrated within common or separate hardware or software components. The data memory 122 may store computer-readable instructions that, when executed by the processing unit 120, cause the processing unit 120 to perform various functions attributed to the processing unit 120 herein. Additionally, the data memory 122 may store parameters for these functions, such as pacing signal parameters, values, conditions, and thresholds described above and below. The pacing instructions and pacing signal parameters, conditions, and thresholds may be updated by a programmer using the communication unit 128. The communication unit 128 may comprise an antenna, a coil, a patient anatomical interface, and / or a transceiver.

[0041] The processing unit 120 may communicate with, and transmit signals to, the pacing signal generator 124 and the detector 126. The pacing signal generator 124 and the detector 126 are electrically coupled to the electrodes 111, 112 of the atrial ILP 100. The detector 126 is configured to monitor signals from the electrodes 111, 112 to monitor the electrical activity of the heart 20 and transmit these signals to the processing unit 120. The pacing signal generator 124 transmits electrical stimulation signals, such as a first electrical signal (pacing pulse) Ap and a second electrical signal (pacing pulse) Ap to the atrium 22 via the electrodes 111, 112. *The processing unit 120 may control the pacing signal generator 124 to generate and deliver the electrical stimuli to the atrium 22 via the electrodes 111, 112. The processing unit 120 may control the pacing signal generator 124 to deliver the electrical stimulation therapy using the pacing information described above and below in accordance with one or more therapy programs including pacing parameters that may be stored in the data memory 122. The pacing signal is generated by the processing unit 120 based on determined atrial pacing time values ​​and / or atrial pacing rate values ​​calculated by the processing unit in accordance with an intrinsic cardiac signal and / or derived from the data memory 122 in accordance with a predetermined therapy program.

[0042] The detector 126 may further include circuitry for acquiring time-dependent electrical signals (e.g., electrical depolarization and repolarization signals, IEGMs) from the heart, including intrinsic cardiac electrical activity, such as intrinsic atrial events and, if applicable, intrinsic ventricular events. Examples of IEGM signals detected by the detector 126 of the atrial ILP 100 are shown in FIG. 4b) and FIG. 5b) or line b) of FIG. 4 and FIG. 5. The detector 126 may filter, amplify, and digitize the acquired electrical events of the heart chamber contractions. The processing unit 120 may receive the detected intrinsic atrial events and, if applicable, intrinsic ventricular events provided by the detector 126. The processing unit 120 may evaluate the cardiac activity signals, including the intrinsic atrial events and, if applicable, intrinsic ventricular events received from the detector 126, and is configured to determine from the IEGM signals the presence or absence of an intrinsic atrial event (p-wave) within a predetermined period from the start of the cardiac cycle in each cardiac cycle.

[0043] The atrial ILP 100 may include a housing, an anchoring feature, and electrodes 111, 112. The housing may have a pill-shaped cylindrical form factor in some examples. The anchoring feature is configured to connect the atrial ILP 100 to the heart 20. The anchoring feature may be fabricated from a shape memory material, such as Nitinol. For example, as shown and described herein with respect to FIG. 1, the anchoring feature may be configured to anchor the atrial ILP 100 to the heart 20 in the right atrium 22. Although the ILP 100 includes multiple anchoring features / elements configured to stably engage the ILP 100 to cardiac tissue in the right atrium, it is contemplated that cardiac pacing devices according to the present disclosure may use other types of anchoring features to engage cardiac tissue in other chambers of the patient's heart 20.

[0044] As described above, the atrial ILP 100 can include two electrodes 111, 112, although in other examples, the cardiac pacing device can include three or more electrodes. The electrodes 111, 112 can be spaced apart a sufficient distance to be able to detect various electrical signals generated by the heart 20, such as p-waves generated by the atria and QRS complexes generated by the ventricles. The housing houses the electronic components of the atrial ILP 100. The electronic components can include any discrete and / or integrated electronic circuit components implementing analog and / or digital circuits capable of generating the functions attributed to the atrial ILP 100 described above and below.

[0045] As shown in FIG. 3, the ventricular ILP 200 may have essentially the same hardware and software structure as the atrial ILP 100, comprising a processing unit 220 with a clock, at least one counter for clock signals and a data memory 222, a pacing signal generator 224, a detector 226, a power source 232 and electrodes 211, 212. The ventricular ILP 200 may also comprise, in one embodiment, a communication unit 228. The power source 232 may be electrically connected to one or more of the other components / units 220, 222, 224, 226, 228 (not shown in FIG. 3). Therefore, reference is made to the above description of the elements and modules with respect to the atrial ILP 100. However, the ventricular ILP 200 is configured to pace the right ventricle 21 of the patient's heart 20. The pacing parameters and treatment programs stored in the data memory 222 are therefore adapted to this function of the ventricular ILP 200. Further, the detector 226 may include circuitry for acquiring time-dependent electrical signals (e.g., electrical depolarization and repolarization signals, IEGMs) from the heart including intrinsic cardiac electrical activity such as intrinsic atrial events, atrial pacing signals, and intrinsic ventricular events. Examples of such IEGMs are shown in FIG. 4c) and FIG. 5c) or lines c) of FIG. 4 and FIG. 5. The detector 226 may filter, amplify, and digitize the IEGM signals. The processing unit 220 may receive the detected intrinsic ventricular events, intrinsic atrial events, and atrial pacing signals provided by the detector 226. The processing unit 220 may evaluate the cardiac activity signals received from the detector 226 and is configured to determine from the IEGM signals the presence or absence of an intrinsic ventricular event within a predetermined period from the start of the cardiac cycle in each cardiac cycle.

[0046] The system 10 shown in Fig. 1 with the atrial ILP 100 and the ventricular ILP 200 implements a modified DDD mode, where the atrial ILP 100 operates according to a modified AAT mode and the ventricular ILP operates according to a VDD mode. This is explained below with respect to the IEGM signals shown in Fig. 4 and Fig. 5. Lines a) in Fig. 4 and Fig. 5 show the pacing pulses Ap, Ap delivered by the atrial ILP 100 and the ventricular ILP 200, respectively. * and Vp only.

[0047] To reduce the energy consumption due to the AAT mode in the atrial ILP 100, a modified AAT mode is implemented that provides a "normal" atrial stimulation (the first electrical signal described above, Ap in FIG. 4) in the absence of an intrinsic atrial event (FIG. 4) and a stimulation of significantly lower amplitude and potentially even different characteristics (the second electrical signal described above, Ap in FIG. 5) in the presence of an intrinsic atrial event (As in FIG. 5). * 4b). The absence of an intrinsic atrial event is observed by the processing unit 120 of the atrial ILP 100 by the absence of a p-wave within a predetermined period from the beginning of each cardiac cycle. In the absence of an intrinsic atrial event, the processing unit 120 triggers the pacing signal generator 124 to provide a pacing signal (first electrical signal) Ap to stimulate an atrial contraction as shown in FIG. 4b). The amplitude depends on the pacing threshold, but is expected to be between 0.5V and 5V (usually about 1-2V), and further, the pulse width is 0.25-1ms (default is 0.25ms), and is a single pulse ("normal pacing pulse"). Thus, this electrical signal Ap can be included or detected in the IEGM of the ventricular ILP 200 shown in FIG. 4c). The processing unit 220 of the ventricle 200 evaluates the Ap signal and concludes, due to detected parameters of this signal, that it is the first electrical signal that provided a "normal" atrial stimulation. The processing unit 220 therefore controls the pacing signal generator 224 to provide a ventricular stimulation Vp (third electrical signal) if not inhibited by an intrinsic ventricular event. This is shown in FIG. 4c).

[0048] When the processing unit 120 observes an intrinsic atrial event As as shown in FIG. 5b), the processing unit 120 generates a second electrical signal Ap at a predetermined time after the detection of the intrinsic atrial event As, for example 0.5 ms after the detection of As (see FIG. 5b), but up to 150 ms after the detection of As, preferably 5 ms after the detection of As. * As described above, the delivered trigger impulse Ap * is a second electrical signal Ap having characteristics equivalent to the pacing stimulus Ap, i.e., an amplitude between 0.01V (or even lower) and the normal amplitude (2V), preferably 0.5V, a pulse width between 0.01ms and the default pulse width of the device (0.25ms), preferably 0.1ms, a double / triple pulse, or * The second electrical signal Ap may have any other pulse pattern that allows for easy and reliable detection and differentiation of the second electrical signal Ap from the first electrical signal Ap. Such a pulse pattern may be used to detect the second electrical signal Ap. * The second electrical signal Ap may consist of a different number of pulses (1-x pulses) and alternatively or additionally of different amplitudes and / or pulse widths, so that a single pulse of the second electrical signal Ap may have the same as well as different characteristics compared to the first electrical signal Ap. * The different characteristics of Ap are detected by the ventricular ILP 200 and a ventricular pacing signal (third electrical signal) Vp is adapted accordingly (see FIG. 5c), and the adapted ventricular pacing signal Vp is provided when not inhibited by an intrinsic ventricular event. * may be shifted in time so that they are provided immediately after the onset of the corresponding intrinsic atrial event As (sense compensation).

[0049] Generally, in this embodiment, the second processing unit 220 is adapted to control the pacing of the right ventricle 21 using a known VDD mode based on the received cardiac activity signal. The counter of the processing unit 220 used to time the AV delay (to provide a ventricular pace signal) may also be used to measure the intrinsic AV delay. The VDD pacing mode may be R-Sync in the ventricular ILP 200. This means that every cycle is synchronized with every ventricular event (intrinsic ventricular contraction or ventricular pacing) used. This also means that the first and second electrical signals Ap and Ap * This is a highly reliable atrial tracking mode with these signals because VDD has a higher amplitude than the intrinsic atrial events As or the paced atrial contractions (see Fig. 4c and Fig. 5c). VDD mode is provided to allow all sensed atrial contractions to shift timing. In other words, VDD is both R-Sync and P-Sync. The timing of the next potential ventricular pacing signal is scheduled based on the most recent ventricular event and the target pacing interval (determined from the target heart rate).

[0050] Heart rate is determined from intrinsic atrial events and, if applicable, from intrinsic ventricular events.

[0051] The reduced amplitude or duration of the signal provided by the atrial ILP 100 reduces the impact on the longevity of triggered pacing. * The different characteristics of the ventricular VDD device are the atrial pace (first electrical signal) Ap and the triggered atrial stimulation (second electrical signal) Ap * and adapt the timing of ventricular pacing by the ventricular ILP 200 accordingly, e.g., providing sensing compensation for the AV delay. The present invention provides a modi AAT (modified) + VDD, resulting in an improved DDD mode with less impact on lifespan and reduced size.

Claims

1. A cardiac pacing device (100) for implantation in a patient's heart, the cardiac pacing device (100) comprising: a processing unit (120) for controlling a pacing signal generator (124); and a detector (126) configured to measure a time-dependent signal of intrinsic atrial activity, the processing unit (120) being configured to detect the presence or absence of an intrinsic atrial event (A.sub.s) within each cardiac cycle based on the measured signal of the atrial activity within the cardiac cycle received from the detector (126), the processing unit controlling the pacing signal generator (124) to provide a first electrical signal (A.sub.p) in the absence of the intrinsic atrial event within the respective cardiac cycle, and to provide a second electrical signal (A.sub.p) in the presence of the intrinsic atrial event (A.sub.s) within the respective cardiac cycle. ＊ ), and the second electrical signal (Ap ＊ ) is different from the first electrical signal (Ap).

2. The first electrical signal (Ap) is configured to effectively pace the myocardium based on at least one predetermined treatment parameter, and the second electrical signal (Ap ＊ 2. The cardiac pacing device of claim 1, wherein the first electrical signal (Ap) has a lower amplitude and / or a lower signal width and / or a different signal morphology compared to the first electrical signal (Ap).

3. The first electrical signal (Ap) is a first pulse signal, and the second electrical signal (Ap ＊ 2. The cardiac pacing device of claim 1, wherein the second electrical signal is a pulse signal consisting of a plurality of pulses provided in succession.

4. The cardiac pacing device of claim 1 , wherein the detector (126) is configured to capture time-dependent electromagnetic and / or electrical and / or acoustic signals of the atrial activity.

5. 10. A system comprising a cardiac pacing device according to any one of claims 1 to 4, as a first cardiac pacing device (100) comprising a first processing unit (120), a first detector (126), and a first pacing signal generator (124), the system further comprising a second cardiac pacing device (200), the second cardiac pacing device (200) comprising a second processing unit (220) for controlling a second pacing signal generator (224) and a second detector (226) configured to measure time-dependent signals of cardiac activity, the second processing unit (220) being configured to identify a pacing signal from the signals of the cardiac activity received from the second detector (226) and determine whether the pacing signal corresponds to the first electrical signal (Ap) provided by the first cardiac pacing device (100) or is different from the second electrical signal (Ap). ＊ ), and the second processing unit (220) is configured to control the second pacing signal generator (224) to provide a third electrical signal (Vp) when ventricular pacing is intended within each cardiac cycle, the third electrical signal (Vp) corresponding to the first electrical signal (Ap) or the second electrical signal (Ap ＊ ) has been previously identified within the same cardiac cycle.

6. 6. The system of claim 5, wherein the second processing unit (220) is further configured to detect the presence and absence of an intrinsic ventricular event from the signal of the cardiac activity received from the second detector, and to provide the third electrical signal (Vp) if the absence of the intrinsic ventricular event is detected within the respective cardiac cycle.

7. The system of claim 5 , wherein the first cardiac pacing device is an atrial ILP (100) and the second cardiac pacing device is a ventricular ILP (200).

8. A method of operating a cardiac pacing device for implantation in a patient's heart, the cardiac pacing device (100) comprising a processing unit (120) for controlling a pacing signal generator (124) and a detector (126) for measuring a time-dependent signal of intrinsic atrial activity, the processing unit (120) detecting the presence or absence of an intrinsic atrial event (A.sub.s) within each cardiac cycle based on the measured signal of the atrial activity within the cardiac cycle received from the detector (126), and the processing unit (120) controlling the pacing signal generator (124) to provide a first electrical signal (A.sub.p) in the absence of the intrinsic atrial event within the respective cardiac cycle and to provide a second electrical signal (A.sub.p) in the presence of the intrinsic atrial event (A.sub.s) within the respective cardiac cycle. ＊ ), and providing the second electrical signal (Ap ＊ ) is different from said first electrical signal (Ap).

9. The first electrical signal (Ap) effectively paces the myocardium based on at least one predetermined treatment parameter, and the second electrical signal (Ap ＊ 9. The method of claim 8, wherein the first electrical signal (Ap) has a lower amplitude and / or a lower electrical signal width and / or a different electrical signal morphology compared to the first electrical signal (Ap).

10. The first electrical signal (Ap) is a first pulse signal, and the second electrical signal (Ap ＊ 9. The method of claim 8, wherein the second electrical signal is a pulse signal consisting of a plurality of pulses provided in succession.

11. The method of claim 8 , wherein the detector (126) captures time-dependent electromagnetic and / or electrical and / or acoustic signals of the atrial activity.

12. 10. A method of operating a system with a cardiac pacing device according to claim 1, wherein the system is a first cardiac pacing device (100) comprising a first processing unit (120), a first detector (126), and a first pacing signal generator (124), the system further comprising a second cardiac pacing device (200), the second cardiac pacing device (200) comprising a second processing unit (220) for controlling a second pacing signal generator (224) and a second detector (226) for measuring time-dependent signals of cardiac activity, the second processing unit (220) identifying a pacing signal from the signals of the cardiac activity received from the second detector (226) and determining whether the pacing signal corresponds to the first electrical signal (Ap) provided by the first cardiac pacing device or is different from the second electrical signal (Ap). ＊ ), and the second processing unit (220) controls the second pacing signal generator (224) to provide a third electrical signal (Vp) when ventricular pacing is intended within each cardiac cycle, the third electrical signal (Vp) corresponding to either the first electrical signal (Ap) or the second electrical signal (Ap). ＊ ) has been previously identified within the same cardiac cycle.

13. 13. The method of claim 12, wherein the second processing unit (220) detects the presence and absence of an intrinsic ventricular event from the signal of the cardiac activity received from the second detector and provides the third electrical signal (Vp) if the absence of the intrinsic ventricular event is detected within the respective cardiac cycle.

14. A computer program product comprising instructions which, when executed by a processing unit (120, 220), cause each processing unit (120, 220) to perform the steps of the method according to any one of claims 8 to 13.

15. 15. A computer readable data carrier storing a computer program product according to claim 14.

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