Implantable medical device for cardiac resynchronization therapy featuring automatic adaptation of stimulation parameters

Abstract

The invention relates to an implantable medical device for stimulating a human or animal heart, the device comprising a single electrode (20) comprising a proximal electrode pole (213) designed and arranged to be implanted within an atrium (2) of the heart (1) to be stimulated and a distal electrode pole (203) designed and arranged to be implanted within a septum (13) of the heart (1) to be stimulated. During operation, the implantable medical device performs the following steps: a) detecting (500) an intrinsic atrial contraction of the heart (1) to be stimulated with the proximal electrode pole (213) or stimulating (500) the atrium (2) of the heart (1) to be stimulated with the proximal electrode pole (213); b) detecting (530) an intrinsic ventricular contraction of the heart (1) to be stimulated with the distal electrode pole (203); c) determining (530) an intrinsic atrioventricular conduction time between i) the intrinsic atrial contraction or the stimulation of the atrium and ii) the intrinsic ventricular contraction; d) setting (550) a stimulated atrioventricular conduction time for stimulating a ventricle (3, 5) of the heart (1) to be stimulated with the distal electrode pole (203), the stimulated atrioventricular conduction time being shorter than the intrinsic atrioventricular conduction time.

Description

Technical Field

[0001] The present invention relates to an implantable medical device according to the preamble of claim 1 and a method of operating such a device according to the preamble of claim 14. Background Technology

[0002] Implantable medical devices used to stimulate the heart of humans or animals can be characterized by different functions. For example, CRT-D devices are designed and arranged to perform cardiac resynchronization therapy and defibrillation of the patient's heart. Such CRT-D devices typically have three electrodes: a combined right ventricular defibrillation and stimulation electrode, a right atrial stimulation and sensing electrode, and a left ventricular coronary sinus electrode. Some manufacturers (such as Biotronik) also offer more complex right ventricular electrodes that integrate atrial sensing functionality into the right ventricular stimulation electrode. However, in this case, it is still necessary to implant two electrodes into or at the heart of the patient. Therefore, solutions known in the prior art require biventricular stimulation with at least two ventricular electrodes. This necessitates a very large connector block (head) of the implantable medical device's stimulation generator, capable of receiving at least two, but often even three, electrode connectors. This large connector block complicates the implantation of the implantable medical device.

[0003] If an implantable medical device is designed and positioned as a CRT-P device—that is, a device for cardiac resynchronization therapy and pacing (but without defibrillation)—the general setup is almost identical to that of the previously described CRT-D device. However, a CRT-P device does not include defibrillation electrodes. Nevertheless, CRT-P devices known in the art typically require a correspondingly large connector block for three different electrodes and a stimulation generator to connect these electrodes to the stimulation generator.

[0004] If the implantable medical device is designed and configured for dual-chamber therapy, two distinct electrodes need to be implanted into the patient's heart. One electrode is guided into the right atrium, and the other into the left ventricle. Both electrodes need to be connected to a stimulation generator (i.e., an implantable pulse generator). For this purpose, the implantable pulse generator typically includes at least two connection sockets. As with the case of a three-socket junction box, this requires a significant amount of space.

[0005] As described above, existing technology has taught specific variants of the integrated electrode that use proximal bipolar to sense electrical signals in the patient's right atrium. This variant of the ventricular electrode has then taken over the function of the atrial electrode. However, this electrode includes a switch with two plugs to allow connection to a conventional biventricular stimulation system. Therefore, integrating the atrial electrode into the ventricular electrode does not change the space requirements of the stimulation generator's connector housing.

[0006] If the sensing and detection capabilities of implantable medical devices are integrated into one or two electrodes, it is still necessary to provide patients with optimal pacing that is appropriate for their health condition. Summary of the Invention

[0007] The purpose of this invention is to provide an implantable medical device that has small space requirements, allows for easy implantation, and enables comprehensive cardiac resynchronization therapy.

[0008] This objective is achieved by an implantable medical device having the features of claim 1 for stimulating the heart of a human or animal.

[0009] This implantable medical device includes a processor, a memory unit, a stimulating unit, and a detecting unit. The stimulating unit is positioned and designed to stimulate the heart of a human or animal. The detecting unit is designed and positioned to detect electrical signals from the same heart. Additionally, the implantable medical device includes proximal and distal electrode bodies that form part of the stimulating and detecting units.

[0010] According to one aspect of the implantable medical device currently claimed and described, a proximal electrode is configured to be implanted within the atrium of the heart to be stimulated. Furthermore, a distal electrode is configured to be implanted within the septum of the heart to be stimulated. At this implantation site, the distal electrode can simultaneously or individually stimulate the left and right ventricles of the heart to be stimulated, for example, through left bundle branch area pacing (LBBAP). Therefore, even if the physiological stimulation line is no longer in operation or is no longer functioning properly, the distal electrode can bypass left bundle branch block and / or right bundle branch block, thereby achieving effective pacing of the left and / or right ventricles.

[0011] The memory unit of an implantable medical device includes a computer-readable program that, when executed on a processor, causes the processor to perform the steps explained below.

[0012] In the first step, the intrinsic atrial contraction of the heart to be stimulated is detected using a proximal electrode. Alternatively, the atria of the heart to be stimulated are stimulated with a proximal electrode to induce atrial contraction.

[0013] In another step of the method, the intrinsic ventricular contraction of the heart to be stimulated is detected using a distal electrode body.

[0014] Subsequently, the intrinsic atrioventricular conduction time is determined. The atrioventricular conduction time is calculated between intrinsic atrial contractions and intrinsic ventricular contractions, or between atrial stimulation and intrinsic ventricular contractions (in response to atrial stimulation). In doing so, a factual measurement reflecting the condition of the physiological cardiac conduction system is obtained.

[0015] In another step, the atrioventricular conduction time of the stimulus is determined from the inherent atrioventricular conduction time, and the atrioventricular conduction time of the stimulus is set for subsequent ventricular stimulation performed by the implantable medical device. This atrioventricular conduction time of the stimulus is used to trigger stimulation of the ventricles of the heart to be stimulated with the distal electrode polarity. In this case, the atrioventricular conduction time of the stimulus is shorter than the inherent atrioventricular conduction time. By applying an atrioventricular conduction time of the stimulus that is shorter than the inherent atrioventricular conduction time, ventricular stimulation, particularly left ventricular stimulation, is ensured to occur safely before any inherent excitation, which is still possible even in the case of left bundle branch block. Therefore, the shortening of the atrioventricular conduction time of the stimulus relative to the inherent atrioventricular conduction time ensures safe ventricular stimulation of the right and left ventricles of the heart to be stimulated by the implantable medical device. Thus, effective cardiac resynchronization is achieved.

[0016] Specifically, the implantable medical device is configured to perform cardiac resynchronization therapy, for example, in the case of left bundle branch block or right bundle branch block. In the case of left or right bundle branch block, right ventricular contraction and left ventricular contraction occur in a temporally shifted manner. In the case of left bundle branch block, the right ventricle contracts first, followed by the left ventricle. In the case of right bundle branch block, the left ventricle contracts first, followed by the right ventricle.

[0017] In one embodiment, the memory unit of the implantable medical device includes a computer-readable program that, when executed on a processor, causes the processor to perform the steps explained below.

[0018] In the first step, the intrinsic atrial contraction of the heart to be stimulated is detected using a proximal electrode. Alternatively, the atria of the heart to be stimulated are stimulated with a proximal electrode to induce atrial contraction.

[0019] In another method step, the intrinsic ventricular contraction of the first ventricle of the heart to be stimulated is detected using a distal electrode body, which occurs first after an intrinsic or induced atrial contraction.

[0020] Subsequently, the intrinsic atrioventricular conduction time is determined. The atrioventricular conduction time is calculated between intrinsic atrial contractions and intrinsic ventricular contractions, or between atrial stimulation and intrinsic ventricular contractions (in response to atrial stimulation). In doing so, a factual measurement reflecting the condition of the physiological cardiac conduction system is obtained.

[0021] In another method step, the atrioventricular conduction time of the stimulus is determined from the inherent atrioventricular conduction time, and the atrioventricular conduction time of the stimulus is set for subsequent ventricular stimulation performed by the implantable medical device. This atrioventricular conduction time of the stimulus is used to trigger stimulation of the second ventricle of the heart to be stimulated with a distal electrode polarity, wherein the second ventricle has been determined to contract temporally delayed compared to the contraction of the first ventricle. In this case, the atrioventricular conduction time of the stimulus is shorter than the inherent atrioventricular conduction time. By applying an atrioventricular conduction time of the stimulus that has been determined based on the first ventricular contraction and is shorter than the inherent atrioventricular conduction time, ventricular stimulation of the second ventricle or diaphragm of the heart is ensured to occur safely before any inherent excitation that may still be possible, i.e., before the inherent excitation of the first ventricle. Therefore, the shortening of the atrioventricular conduction time of the stimulus relative to the inherent atrioventricular conduction time ensures safe ventricular stimulation of the right and left ventricles of the heart to be stimulated by the implantable medical device. Thus, effective cardiac resynchronization is achieved.

[0022] In one embodiment, the implantable medical device includes a single ventricular electrode, wherein the single ventricular electrode includes a distal electrode polarity for determining the intrinsic atrioventricular conduction time and stimulating a second ventricle.

[0023] In one embodiment, in the event that any physiological changes over time alter the inherent atrioventricular conduction time, the implantable medical device is configured to adapt the atrioventricular conduction time of the stimulus to the determined and modified inherent atrioventricular conduction time, such that the stimulus provided by the implantable medical device can track the condition of the heart to be stimulated and reflect highly physiological stimulation.

[0024] In one embodiment, the proximal electrode is configured to be implanted in the right atrium, and when the computer-readable program is executed on the processor, the processor performs the following steps: a) detecting intrinsic right atrial contraction of the heart to be stimulated using the proximal electrode, or stimulating the right atrium of the heart to be stimulated using the proximal electrode; b) detecting intrinsic right ventricular contraction of the heart to be stimulated using the distal electrode.

[0025] c) Determine the intrinsic atrioventricular conduction time between i) intrinsic right atrial contraction or stimulation of the right atrium and ii) intrinsic right ventricular contraction; d) Set the atrioventricular conduction time of stimulation for stimulating the left ventricle of the heart to be stimulated with the distal electrode, wherein the stimulation atrioventricular conduction time is shorter than the intrinsic atrioventricular conduction time. At this implantation site, the distal electrode can stimulate at least the left ventricle of the patient's heart via left bundle branch area pacing (LBBAP). Therefore, even if the physiological stimulation line is no longer working or is no longer working correctly, the distal electrode can bypass the left bundle branch block, thereby achieving effective pacing of the left ventricle.

[0026] In one embodiment, the proximal electrode body is part of an atrial electrode implanted in the right atrium. The atrial electrode can be secured distally to the atrial wall of the right atrium. Alternatively, the distal electrode body can be part of a ventricular electrode implanted in the right ventricle. The ventricular electrode can be secured within the septum of the heart.

[0027] In one embodiment, the proximal and distal electrode bodies are part of a single electrode implanted in the right atrium and right ventricle and secured within the septum of the heart. In this embodiment, the proximal electrode is not fixed to the atrial wall but can float within the right atrium.

[0028] In one embodiment, the proximal electrode is a single electrode. In this embodiment, the housing of the implantable medical device can be used as a paired electrode for sensing atrial signals and / or for stimulating the atria of the heart to be stimulated.

[0029] In one embodiment, the proximal electrode is bipolar. This proximal bipolar is arranged and designed to detect intrinsic atrial signals of the heart to be stimulated. After implantation of a single electrode of the implantable medical device, the proximal bipolar is located within the right atrium, allowing the intrinsic atrial signals sensed by the proximal bipolar to be used to trigger further stimulation pulses to deliver LBBAP stimulation to the ventricles of the heart. In this case of proximal bipolar, it is not necessary to use the housing of the implantable medical device as a pairing electrode. Instead, one of the electrode electrodes of the proximal bipolar can be used as a pairing electrode for the corresponding other electrode electrode of the proximal bipolar.

[0030] In one embodiment, the proximal bipolar includes two annular electrodes spaced apart from each other.

[0031] In one embodiment, the ventricular electrode or a single electrode includes a helix at its distal end. This helix is ​​designed and configured to be anchored within the cardiac tissue. For this purpose, the helix can be rotated into the cardiac tissue, specifically into the septum of the patient's heart. After implantation of the ventricular electrode or single electrode into the septum, particularly the deep septum, effective stimulation of the left ventricle can be achieved even without an electrode placed directly within or outside the left ventricle (as in the case of prior art left ventricular stimulation electrodes). Implantation of the distal electrode polarity in the deep septum at a location distal to left bundle branch block enables left bundle branch region pacing without the need for a separate left ventricular electrode.

[0032] In one embodiment, the helix is ​​designed as a fixed, stationary helix. In another embodiment, the helix is ​​designed as a screw-out fixed helix. Either design is particularly suitable for securing a ventricular electrode or a single electrode within the septum of a patient's heart.

[0033] In one embodiment, the distal electrode is a single electrode. For sensing and stimulation functions, the housing of the implantable medical device is then used as a paired electrode for the single distal electrode.

[0034] In one embodiment, the distal electrode is a distal bipolar. This distal bipolar is arranged and designed to detect the intrinsic right ventricular signal of the heart to be stimulated. After implantation of a ventricular electrode or a single electrode of an implantable medical device, the distal bipolar is located within the septum of the heart to be stimulated. At this implantation site, the distal bipolar is well-suited to provide stimulation pulses for LBBAP, as described above for a single distal electrode. In the case of this distal bipolar, it is not necessary to use the housing of the implantable medical device as a mating electrode. Instead, one of the electrode electrodes of the distal bipolar can be used as a mating electrode for the corresponding other electrode electrode of the distal bipolar.

[0035] In one embodiment, the aforementioned helix forms at least a portion of the distal bipolar electrode. In other words, at least one electrode element (particularly both electrode elements) of the distal bipolar electrode is realized by a helix, which also serves to secure at least one electrode within the septum of the patient's heart. This ensures highly efficient energy transfer from the ventricular electrode or a single electrode to the surrounding cardiac tissue.

[0036] The distal bipolar electrode comprises a first electrode and a second electrode located proximal to the first electrode. In one embodiment, the distance between the distal end of the second electrode and the proximal end of the first electrode is in the range of 1 mm to 30 mm, particularly 2 mm to 25 mm, particularly 3 mm to 20 mm, particularly 4 mm to 15 mm, and particularly 5 mm to 10 mm. This distance between the first and second electrode is particularly suitable for allowing the first and second electrode to stimulate different cardiac regions after the electrodes are implanted in the patient's cardiac septum. The first electrode can then stimulate the left bundle branch, i.e., it can perform left bundle branch area pacing (LBBAP). Similarly, the second electrode can then stimulate the right bundle branch, i.e., it can perform right bundle branch area pacing (RBBAP). Furthermore, the second electrode can detect right ventricular signals particularly well in this location.

[0037] In one embodiment, a computer-readable program causes a processor to subtract a predetermined absolute value from a determined inherent atrioventricular conduction time to determine the atrioventricular conduction time of a stimulus, and then sets it for use in a further stimulus event. In one embodiment, the absolute value to be subtracted is in the range of 1 ms to 100 ms, particularly 2 ms to 95 ms, particularly 3 ms to 90 ms, particularly 4 ms to 85 ms, particularly 5 ms to 80 ms, particularly 6 ms to 75 ms, particularly 7 ms to 70 ms, particularly 8 ms to 65 ms, particularly 8 ms to 60 ms, particularly 9 ms to 55 ms, particularly 10 ms to 50 ms, particularly 15 ms to 45 ms, particularly 20 ms to 40 ms, particularly 25 ms to 35 ms.

[0038] In one embodiment, a computer-readable program causes a processor to subtract a predetermined relative value from a determined intrinsic atrioventricular conduction time to define the atrioventricular conduction time of a stimulus, which is then set for a subsequent stimulation event performed by an implantable medical device. In one embodiment, the relative value to be subtracted is in the range of 1% to 50%, particularly 10% to 50%, particularly 2% to 45%, particularly 3% to 40%, particularly 4% to 35%, particularly 5% to 30%, particularly 6% to 25%, particularly 7% to 20%, particularly 8% to 15%, and particularly 9% to 10%. Subtracting such a relative value can adjust the intrinsic atrioventricular conduction time, thereby producing the atrioventricular conduction time of the stimulus in a more physiological manner than can generally be achieved by subtracting an absolute value.

[0039] In one embodiment, a computer-readable program causes a processor to periodically repeat the following steps: a) detecting intrinsic atrial contraction or stimulating the right atrium, b) detecting intrinsic right ventricular contraction of the heart, c) determining the intrinsic atrioventricular conduction time, and d) setting the stimulated atrioventricular conduction time after a predetermined number of cardiac cycles and / or after a predetermined time interval. In doing so, the stimulated atrioventricular conduction time can be continuously adapted to potentially changing intrinsic atrioventricular conduction times in an efficient manner. This regular repetition can also be represented as cyclic measurement.

[0040] In one embodiment, the method steps explained above are repeated after a predetermined number of cardiac cycles, wherein the predetermined number is in the range of 10 to 1000, particularly 20 to 900, particularly 30 to 800, particularly 40 to 700, particularly 50 to 600, particularly 60 to 500, particularly 70 to 400, particularly 80 to 300, particularly 90 to 200, particularly 100 to 150.

[0041] In one embodiment, the repetition occurs after a predetermined time period has elapsed, wherein the predetermined time period is in the range of 10 seconds to 1000 seconds, particularly 20 seconds to 900 seconds, particularly 30 seconds to 800 seconds, particularly 40 seconds to 700 seconds, particularly 50 seconds to 600 seconds, particularly 60 seconds to 500 seconds, particularly 70 seconds to 400 seconds, particularly 80 seconds to 300 seconds, particularly 90 seconds to 200 seconds, particularly 100 seconds to 150 seconds.

[0042] In one embodiment, when performing the step of determining the intrinsic atrioventricular conduction time, a computer-readable program causes the processor to increase the atrioventricular conduction time of the stimulus by an amount longer than the expected intrinsic atrioventricular conduction time. This increase in the atrioventricular conduction time of the stimulus results in an atrioventricular conduction time of the stimulus that is longer than the intrinsic atrioventricular conduction time. Therefore, stimulation with the applied atrioventricular conduction time does not cause cardiac contraction (because the heart is still in its refractory period) or at least does not interfere with physiological intrinsic ventricular contraction, thereby allowing for easy recording and use of updated values ​​of the intrinsic atrioventricular conduction time to define updated values ​​of the atrioventricular conduction time of the stimulus.

[0043] In one embodiment, a computer-readable program enables a processor to detect intrinsic ventricular contractions, particularly intrinsic right ventricular contractions, by evaluating a far-field electrocardiogram measured between a distal electrode and the housing of an implantable medical device. This evaluation of the far-field electrocardiogram presents a particularly suitable possibility for detecting intrinsic cardiac activity with a single electrode, especially a single distal electrode. Therefore, when relying on evaluation using a far-field electrocardiogram, a second distal electrode is not necessary. This reduces the number of electrode leads to be guided within the electrode and thus reduces the complexity of a single electrode in the implantable medical device.

[0044] In one embodiment, the implantable medical device includes a shock coil located between a distal electrode and a proximal electrode. This shock coil is well-suited for delivering a defibrillation shock to the heart to be stimulated. The implantable medical device can then be used as a CRT-D device. In this embodiment, a computer-readable program causes a processor to detect intrinsic ventricular contractions, particularly intrinsic right ventricular contractions, by evaluating a far-field electrocardiogram measured between the shock coil and the housing of the implantable medical device. The far-field electrocardiogram measured between the shock coil and the housing of the implantable medical device may include a stronger signal than the far-field electrocardiogram measured between the distal electrode and the housing of the implantable medical device.

[0045] In one embodiment, the shock coil has a surface area of ​​at least 150 mm², particularly at least 175 mm², particularly at least 200 mm², particularly at least 225 mm², particularly at least 250 mm². Such a surface allows the shock coil to deliver a sufficiently large shock pulse to achieve effective cardiac defibrillation of the patient's heart.

[0046] In one embodiment, a computer-readable program causes a processor to use the earliest point in time of ventricular excitation, particularly right ventricular excitation, as a measure of intrinsic ventricular contraction, particularly intrinsic right ventricular contraction. Typically, the earliest point in time of ventricular excitation is the beginning of the so-called QRS complex on an electrocardiogram (ECG). This QRS complex represents ventricular excitation during the cardiac cycle. The beginning of the QRS complex can be used as an indication of the timing of intrinsic ventricular contraction when evaluating a routine ECG (measured between two electrode poles, both located on a single electrode) and when evaluating a far-field ECG (measured between an electrode pole on a single electrode and the housing of an implantable medical device). The beginning of the QRS complex is a particularly suitable point in time for defining the onset of intrinsic ventricular contraction, which is used to determine the intrinsic atrioventricular conduction time.

[0047] In one embodiment, the determination of the earliest time point of ventricular excitation, particularly right ventricular excitation, is accomplished via morphological signal assessment. For example, the combination of the slope of the signal curve (also known as the signal rise rate) and the minimum amplitude is a particularly suitable morphological measurement for identifying the earliest time point of ventricular excitation from a measured signal curve (such as an electrocardiogram). As mentioned above, the electrocardiogram can be a conventional electrocardiogram or a far-field electrocardiogram.

[0048] In one embodiment, a computer-readable program causes a processor to perform the step of setting the atrioventricular conduction time of a stimulus only when the determined intrinsic atrioventricular conduction time is within a predetermined range. If the intrinsic atrioventricular conduction time is outside the predetermined range, the atrioventricular conduction time of the stimulus is set to a predetermined fixed value. This embodiment prevents the setting of atrioventricular conduction times for non-physiological stimuli when the intrinsic atrioventricular conduction time is calculated from atypical cardiac cycles (e.g., cardiac cycles including atrial extra-terminal contractions). Therefore, this embodiment increases the safety of the implantable medical device and ensures a high degree of user-friendliness.

[0049] In one embodiment, the predeterminable range of atrioventricular conduction time is from 0.08 s to 0.25 s, particularly from 0.10 s to 0.25 s, particularly from 0.12 s to 0.22 s, particularly from 0.13 s to 0.20 s, particularly from 0.14 s to 0.18 s.

[0050] In one embodiment, the computer-readable program instructs the processor to set the atrioventricular conduction time of the stimulus only to a value within a predetermined range. This embodiment also increases the safety of the implantable medical device. It ensures that the implantable medical device applies only physiologically perceptible atrioventricular conduction time of the stimulus during its operation.

[0051] In one embodiment, the permissible and predeterminable range of the atrioventricular conduction time of the stimulus is from 0.05 s to 0.20 s, particularly from 0.10 s to 0.15 s, particularly from 0.11 s to 0.12 s, particularly from 0.12 s to 0.13 s.

[0052] In one embodiment, the proximal electrode and the distal electrode are part of a single electrode, wherein the proximal electrode is designed and arranged to float within the right atrium in its implanted state. In one aspect, the present invention relates to a method for operating an implantable medical device according to the foregoing description. The method includes the steps explained below.

[0053] In the first step, the intrinsic atrial contraction of the heart to be stimulated is detected using a proximal electrode body.

[0054] In another step of the method, the intrinsic ventricular contraction of the heart to be stimulated is detected using a distal electrode body.

[0055] Subsequently, the intrinsic atrioventricular conduction time is determined. The atrioventricular conduction time is calculated between intrinsic atrial contractions and intrinsic ventricular contractions. In doing so, a factual measurement reflecting the condition of the physiological cardiac conduction system is obtained.

[0056] In another method step, the atrioventricular conduction time of the stimulus is determined from the intrinsic atrioventricular conduction time, and this atrioventricular conduction time is set for subsequent ventricular stimulation performed by an implantable medical device. This atrioventricular conduction time of the stimulus is used to trigger stimulation of the ventricle of the heart to be stimulated with the distal electrode polarity. In this case, the atrioventricular conduction time of the stimulus is shorter than the intrinsic atrioventricular conduction time. By applying an atrioventricular conduction time of the stimulus shorter than the intrinsic atrioventricular conduction time, ventricular stimulation, particularly left ventricular stimulation, is ensured to occur safely before any intrinsic excitation, even in the case of left and / or right bundle branch block, where intrinsic excitation remains possible.

[0057] In one embodiment, a method for operating an implantable medical device includes the following steps: a) detecting intrinsic right atrial contraction of a heart to be stimulated using a proximal electrode polarity; b) detecting intrinsic right ventricular contraction of the heart to be stimulated using a distal electrode polarity; c) determining the intrinsic atrioventricular conduction time between the intrinsic right atrial contraction and the intrinsic right ventricular contraction; and d) setting the atrioventricular conduction time of stimulation for stimulating the left ventricle of the heart to be stimulated with the distal electrode polarity, wherein the atrioventricular conduction time of stimulation is shorter than the intrinsic atrioventricular conduction time.

[0058] In one aspect, the present invention relates to a medical method for providing cardiac resynchronization therapy to patients in need. The method includes the steps explained below.

[0059] In the first step, the proximal electrode of an implantable medical device for stimulating the human or animal heart is used to detect the intrinsic atrial contraction of the heart to be stimulated. Alternatively, the atria of the heart to be stimulated are stimulated using the proximal electrode to induce atrial contraction. The implantable medical device described above is particularly suitable for performing this method.

[0060] In another step of the method, the intrinsic ventricular contraction of the heart to be stimulated is detected using a distal electrode, which is part of an electrode identical to the proximal electrode or part of a second (separate) electrode, as explained above. In this case, the distal electrode is implanted within the septum of the patient's heart.

[0061] Subsequently, the intrinsic atrioventricular conduction time is determined. The atrioventricular conduction time is calculated between intrinsic atrial contractions and intrinsic ventricular contractions, or between atrial stimulation and intrinsic ventricular contractions (in response to atrial stimulation). In doing so, a factual measurement reflecting the condition of the physiological cardiac conduction system is obtained.

[0062] In another method step, the atrioventricular conduction time of the stimulus is determined from the inherent atrioventricular conduction time, and this atrioventricular conduction time is set for subsequent ventricular stimulation performed by an implantable medical device. This atrioventricular conduction time of the stimulus is used to trigger stimulation of the patient's ventricles with a distal electrode. In this case, the atrioventricular conduction time of the stimulus is shorter than the inherent atrioventricular conduction time.

[0063] Finally, at the end of the atrioventricular conduction time of the stimulation, at least one stimulation pulse emitted by the distal electrode is used to stimulate the ventricle of the patient's heart. This at least one stimulation pulse is used for effective cardiac resynchronization of the patient's heart.

[0064] In another embodiment, the method for providing cardiac resynchronization particularly includes the following steps: a) detecting intrinsic right atrial contraction of the heart to be stimulated using a proximal electrode polarity or stimulating the right atrium of the heart to be stimulated using a proximal electrode polarity, wherein the proximal electrode polarity is implanted in the right atrium of the patient's heart; b) detecting intrinsic right ventricular contraction of the heart to be stimulated using a distal electrode polarity, wherein the distal electrode polarity is implanted in the septum of the patient's heart; c) determining the intrinsic atrioventricular conduction time between i) intrinsic right atrial contraction or stimulation of the right atrium and ii) intrinsic right ventricular contraction; d) setting the atrioventricular conduction time of stimulation for stimulating the left ventricle of the patient's heart, wherein the atrioventricular conduction time of stimulation is shorter than the intrinsic atrioventricular conduction time; e) stimulating the left ventricle of the patient's heart with a distal electrode polarity.

[0065] All embodiments of the implantable medical device can be combined in any desired manner and can be transferred individually or in any arbitrary combination to each method. Similarly, all embodiments of each method can be combined in any desired manner and can be transferred individually or in any arbitrary combination to the implantable medical device and the corresponding other methods. Attached Figure Description

[0066] Further details of aspects of the invention will now be explained with reference to exemplary embodiments and the accompanying drawings. In the drawings:

[0067] Figure 1 A first embodiment of an implantable medical device implanted into the human heart is shown;

[0068] Figure 2 A second embodiment of an implantable medical device implanted into the human heart is shown;

[0069] Figure 3 A third embodiment of an implantable medical device implanted into the human heart is shown;

[0070] Figure 4 A fourth embodiment of an implantable medical device implanted into the human heart is shown;

[0071] Figure 5 Different components of an embodiment of an implantable medical device are schematically shown; and

[0072] Figure 6 A schematic flowchart illustrating an embodiment of a method performed by an implantable medical device during operation is shown. Detailed Implementation

[0073] Figure 1 A human heart 1 is shown, in which a biventricular electrode 20 and an atrial electrode 21 are implanted. Both the biventricular electrode 20 and the atrial electrode 21 are guided through the superior vena cava 12 into the right atrium 2. Furthermore, the biventricular electrode 20 is guided into the right ventricle 3 and secured within the septum 13 separating the right ventricle 3 from the left ventricle 5. The biventricular electrode 20 is implanted deep within the septum, allowing it to stimulate the left bundle branch of the human heart 1, thereby stimulating the left ventricle 5, even though it does not directly contact the left ventricle 5.

[0074] The atrial electrode 21 is used to detect atrial signals and / or stimulate atrial tissue. For this purpose, the atrial electrode 21 includes a first atrial electrode body 211 and a second atrial electrode body 212 located proximal to the first distal atrial electrode body 211. The first atrial electrode body 211 and the second atrial electrode 212 form an atrial bipolar 213 that is at least partially implanted in the atrial tissue. This atrial bipolar 213 represents the proximal electrode body.

[0075] The biventricular electrode 20 includes a first distal electrode 201 and a second distal electrode 202 located proximal to the first distal electrode 201. The first distal electrode 201 and the second distal electrode 202 form a distal bipolar 203 representing the distal electrode. The distal bipolar 203 is fixed within the diaphragm 13 of the patient's heart 1.

[0076] The biventricular electrode 20 and the atrial electrode 21 form part of a CRT-P device 22, which represents an implantable medical device. The CRT-P device 22 includes a stimulation generator 23 (also referred to as a housing), which includes a head 230. The biventricular electrode 20 and the atrial electrode 21 are inserted into electrode connector receiver sockets using their electrode connectors.

[0077] Figure 2 Another embodiment of the CRT-P device 22 implanted in a human heart 1 is shown, which is similar to Figure 1 The embodiments shown are very similar. In this figure and all subsequent figures, similar elements will be indicated by the same reference numerals. The CRT-P device 22 includes a biventricular electrode 20 guided through the superior vena cava 12 into the right atrium 2. Furthermore, the biventricular electrode 20 is guided into the right ventricle 3 and secured within a septum 13 separating the right ventricle 3 from the left ventricle 5. The biventricular electrode 20 is implanted in a deep septal location such that it can stimulate the left bundle branch of the human heart 1, thereby stimulating the left ventricle 5, even though it does not directly contact the left ventricle 5 (nor the left atrium 4).

[0078] The biventricular electrode 20 includes a distal electrode body 203, which has a spiral shape and is fixed within the diaphragm 13 of the patient's heart 1.

[0079] The CRT-P device 22 also includes a stimulation generator 23, which includes a head 230. Since the biventricular electrode 20 is the only electrode in the CRT-P device 22, the head 230 is significantly smaller than the heads of prior art stimulation generators, as it requires only the space needed for a single electrode connector receiver socket. The biventricular electrode 20 is inserted into this electrode connector receiver socket using its electrode connector.

[0080] The biventricular electrode 20 includes an atrial electrode 213 serving as the proximal electrode polarity. It is located on the biventricular electrode 20 such that it is positioned in a floating position within the right atrium after implantation of the CRT-P device 22. The atrial electrode 213 is used to detect atrial signals and / or stimulate atrial tissue.

[0081] During operation of the CRT-P device 22, a far-field electrocardiogram is measured between the distal electrode 203 and the stimulation generator 23 and / or between the atrial electrode 213 and the housing 23.

[0082] Figure 3 Another embodiment of the CRT-P device 22 implanted in a human heart 1 is shown, which is very similar to Figure 2 The embodiment shown.

[0083] and Figure 2 The embodiments shown are the opposite. Figure 3 The CRT-P device 22 has biventricular electrodes 20 including a distal bipolar 203 and an atrial bipolar 213.

[0084] The distal bipolar 203 includes a first distal electrode 201 and a second distal electrode 202 located proximal to the first distal electrode 201. The distal bipolar 203 is fixed within the diaphragm 13 of the patient's heart 1 by a spiral of the first distal electrode 201 forming the distal bipolar 203.

[0085] The atrial electrode 213 of the biventricular electrode 20 is designed as atrial bipolar 213. It includes a first atrial electrode 211 and a second atrial electrode 212 located proximal to the first distal atrial electrode 211.

[0086] Instead of like in Figure 1 and Figure 2 In the embodiment shown, the far-field electrocardiogram is measured between the distal electrode 203 and the stimulator 23 and / or between the atrial electrode 213 and the stimulator 23. The distal bipolar 203 and the atrial bipolar 213 enable the near-field electrocardiogram to be measured between the first distal electrode 201 and the second distal electrode 202 on the one hand, and the near-field electrocardiogram to be measured between the first atrial electrode 211 and the second electrode 212 on the other hand.

[0087] Figure 4 An embodiment of the CRT-D device 22 is shown, which is very similar to Figure 3 The CRT-P device 23 shown includes, additionally, a shock coil 210 on the biventricular electrodes 20 located between the distal electrode 203 and the atrial electrode 213. This shock coil 210 is capable of delivering a defibrillation shock to the heart 1 in cases requiring not only resynchronization but also defibrillation. Therefore, Figure 4 The biventricular electrode 20 of the embodiment shown is capable of providing CRT-D therapy. In other words, the biventricular electrode 20 is formed as part of a CRT-D system 22, which is an example of an implantable medical device.

[0088] The shock coil 210 can also be used to measure the far-field electrocardiogram between the shock coil 210 and the stimulation generator 23. Therefore, Figure 4The illustrated embodiment provides the possibility of measuring near-field electrocardiograms (between the individual electrode poles of the distal bipolar 203 or atrial bipolar 213) and between the shock coil 210 and the stimulation generator 23. Alternatively, any of the first distal electrode pole 201, the second distal electrode pole 202, the first atrial electrode pole 211, and the second atrial electrode pole 212 can be used to measure far-field electrocardiograms of the housing 23 of the CRT-D device 22.

[0089] Figure 5 Various components of an embodiment of an implantable medical device are schematically shown, for example... Figures 1 to 4 The illustrated embodiment includes a stimulator 23 within an implantable medical device. The stimulator 23 houses a detection unit 231 (also referred to as a sensing unit), which typically includes an analog-to-digital converter, a bandpass filter, and offset compensation. The detection unit 231 is operatively connected to a processor 232 with access to a memory unit 233. The memory unit 233 stores instructions for the processor 232 and data detected by the detection unit 231. The stimulator 23 may also optionally include an evaluation unit 234, which may also be part of the processor 232 and is used to extract features from the detected electrocardiogram (ECG) signals. The stimulator 23 also includes a stimulation unit 235 for stimulating the heart, from which the detection unit 231 detects electrical signals. A biventricular electrode 20 (along with its electrode bodies 203 and 213; see [link]). Figures 1 to 4 This forms part of the detection unit 231 and the stimulation unit 235. Additionally, the stimulation generator 23 includes a communication unit 236 for transmitting data to a (remote) programming device.

[0090] Figure 6 The implantable medical devices currently claimed and described are shown (such as...) Figure 1 , 2 And 3 implantable CRT-P devices 22 or Figure 4 A schematic flowchart illustrating the cyclic adaptation of atrioventricular conduction time of stimulation performed in an embodiment of the implantable CRT-D device 22). Reference will now be made to... Figures 1 to 4 Explain in more detail Figure 6 The method described in the text.

[0091] In the atrial sensing / atrial pacing step 500, the proximal electrode 213 of the biventricular electrode 20 of the CRT-P device 22 or the CRT-D device 22 is used to detect the intrinsic atrial contraction of the heart 1 (see [link to device details]). Figures 1 to 4 Alternatively, the proximal electrode 213 is used to stimulate the right atrium 2 of the patient's heart 1 during the atrial sensing / atrial pacing step 500.

[0092] In the subsequent first decision step 510, it is determined whether the detected atrial rate is within a predetermined limit. If so ("y" indicates "yes"), the method proceeds to the second decision step 520. If not ("n" indicates "no"), the atrioventricular conduction time of the stimulus applied by the implantable CRT-P / CRT-D device 22 is set to a programmed atrioventricular delay in the setting step 570. The CRT-P / CRT-D device 22 then continues pacing for a predetermined number of cardiac cycles (such as 60 cycles) in the pacing step 580 with the programmed atrioventricular delay applied. Afterward, the method returns to the initial atrial sensing / atrial pacing step 500.

[0093] Assuming the first decision step 510 results in an atrial rate within a predetermined limit, the second decision step 520 determines whether the sensed atrial signal is a regular atrial signal (y) or is considered to be an atrial premature contraction (n). If an atrial premature contraction is detected (or suspected), the method proceeds to the setup step 570 as described above. However, if the sensed atrial signal is considered a regular atrial signal, the method proceeds to the atrioventricular delay measurement step 530.

[0094] In this atrioventricular delay measurement step 530, the intrinsic atrioventricular conduction time (also known as atrioventricular delay) is determined. For this purpose, a non-physiological long-stimulation atrioventricular delay is set. Optionally, the ventricular trigger signal is paused. Therefore, pacing by the CRT-P / CRT-D device 22 will not occur at all or will only occur after the intrinsic (right) ventricular contraction. This makes it possible to measure the intrinsic atrioventricular conduction time.

[0095] In the third decision step 540, it is determined whether the measured intrinsic atrioventricular conduction time is within a predetermined time limit. If not (n), the method continues with the setup step 570 as described above. However, if the measured intrinsic atrioventricular conduction time is within a predetermined time limit (y), the method proceeds to the adjustment step 550, where the atrioventricular delay of the stimulus is set based on the determined intrinsic atrioventricular delay. In this case, the atrioventricular delay of the stimulus is set shorter than the determined intrinsic atrioventricular delay. In doing so, it is ensured that the stimulus provided by the CRT-P / CRT-D device 22 is provided earlier than the intrinsic ventricular contraction that will occur. Therefore, the provided stimulus will cause synchronous contraction of the right ventricle 3 and left ventricle 5 of the patient's heart 1.

[0096] The stimulation with the atrioventricular delay set in adjustment step 550 is performed in pacing step 560 for a predetermined number of cardiac cycles, such as 60 cycles. Afterward, the method returns to atrial sensing / atrial pacing step 500. The atrioventricular delay of the stimulation is then readjusted such that any physiological changes in the inherent atrioventricular conduction time are reflected in the atrioventricular conduction time of the stimulation in a highly timely manner.

Claims

1. An implantable medical device for stimulating the heart of a human or animal, comprising a processor (232), a memory unit (233), a stimulation unit (235) configured to stimulate the heart (1) of a human or animal, a detection unit (231) configured to detect electrical signals of the same heart (1), and a proximal electrode (213) and a distal electrode (203) both forming part of the stimulation unit (235) and the detection unit (231). Its features The proximal electrode (213) is designed and arranged to be implanted in the atrium (2) of the heart (1) to be stimulated, and the distal electrode (203) is designed and arranged to be implanted in the septum (13) of the heart (1) to be stimulated, and the memory unit (233) includes a computer-readable program that, when executed on the processor (232), causes the processor (232) to perform the following steps: a) Detect (500) the intrinsic atrial contraction of the heart (1) to be stimulated using the proximal electrode (213), or stimulate (500) the atrium (2) of the heart (1) to be stimulated using the proximal electrode (213). b) Detect (530) the intrinsic ventricular contraction of the heart (1) to be stimulated using the distal electrode polarity (203); c) Determine (530) i) the intrinsic atrioventricular conduction time between the intrinsic atrial contraction or the stimulation of the atrium and ii) the intrinsic ventricular contraction; d) Set the atrioventricular conduction time of the (550) stimulation for stimulating the ventricles (3, 5) of the heart (1) to be stimulated by the distal electrode (203), wherein the atrioventricular conduction time of the stimulation is shorter than the inherent atrioventricular conduction time.

2. The implantable medical device according to claim 1, characterized in that, The proximal electrode is configured to be implanted in the right atrium, and the computer-readable program, when executed on the processor (232), causes the processor (232) to perform the following steps: a) Detect (500) the intrinsic right atrial contraction of the heart (1) to be stimulated using the proximal electrode (213), or stimulate (500) the right atrium (2) of the heart (1) to be stimulated using the proximal electrode (213). b) Detect (530) the intrinsic right ventricular contraction of the heart (1) to be stimulated using the distal electrode polarity (203); c) Determine (530) i) the intrinsic atrioventricular conduction time between the intrinsic right atrial contraction or the stimulation of the right atrium and ii) the intrinsic right ventricular contraction; d) Set the atrioventricular conduction time of the stimulation (550) for stimulating the left ventricle (5) of the heart (1) to be stimulated by the distal electrode (203), wherein the atrioventricular conduction time of the stimulation is shorter than the inherent atrioventricular conduction time.

3. The implantable medical device according to claim 1 or 2, characterized in that, At least one of the proximal electrode (213) and the distal electrode (203) is a single electrode or a bipolar electrode.

4. The implantable medical device according to any one of the preceding claims, characterized in that, The computer-readable program causes the processor (232) to subtract a predetermined absolute value from the determined inherent atrioventricular conduction time to define the atrioventricular conduction time of the stimulus.

5. The implantable medical device according to any one of the preceding claims, characterized in that, The computer-readable program causes the processor (232) to subtract a predetermined relative value from the determined inherent atrioventricular conduction time to define the atrioventricular conduction time of the stimulus.

6. The implantable medical device according to any one of the preceding claims, characterized in that, The computer-readable program causes the processor (232) to periodically repeat steps a) to d) after a predetermined number of cardiac cycles and / or after a predetermined time interval.

7. The implantable medical device according to any one of the preceding claims, characterized in that, When step c) is to be performed, the computer-readable program causes the processor (232) to increase the atrioventricular conduction time of the stimulus by an amount longer than the expected inherent atrioventricular conduction time.

8. The implantable medical device according to any one of the preceding claims, characterized in that, The computer-readable program enables the processor (232) to detect the intrinsic ventricular contraction by evaluating a far-field electrocardiogram measured between the distal electrode (203) and the housing (23) of the implantable medical device (22).

9. The implantable medical device according to any one of the preceding claims, characterized in that, The implantable medical device includes an electric shock coil (210) located between the distal electrode (203) and the proximal electrode (213), and the computer-readable program enables the processor (232) to detect the intrinsic ventricular contraction by evaluating a far-field electrocardiogram measured between the electric shock coil (210) and the housing (23) of the implantable medical device (22).

10. The implantable medical device according to claim 8 or 9, characterized in that, The computer-readable program causes the processor (232) to use the earliest point in time of ventricular excitation as a measure of the inherent ventricular contraction.

11. The implantable medical device according to the preceding claim, characterized in that, The computer-readable program enables the processor (232) to determine the earliest time point of ventricular excitation by evaluating the morphological signals of the far-field electrocardiogram.

12. The implantable medical device according to any one of the preceding claims, characterized in that, The computer-readable program causes the processor (232) to perform step d) only if the determined inherent atrioventricular conduction time is within a predetermined range, and to set the atrioventricular conduction time of the stimulus to a predetermined fixed value if the determined inherent atrioventricular conduction time is outside a predetermined range.

13. The implantable medical device according to any one of the preceding claims, characterized in that, The proximal electrode (213) and the distal electrode (203) are part of a single electrode, wherein the proximal electrode is designed and arranged to float within the right atrium (2).

14. A method for operating an implantable medical device (22) according to any one of the preceding claims, the method comprising the steps of: a) Detect (500) the intrinsic atrial contraction of the heart (1) to be stimulated using the proximal electrode polarity (213); b) Detect (530) the intrinsic ventricular contraction of the heart (1) to be stimulated using the distal electrode polarity (203); c) Determine the proper atrioventricular conduction time between the proper atrial contraction and the proper ventricular contraction of (530); d) Set the atrioventricular conduction time of the (550) stimulation for stimulating the ventricles (3, 5) of the heart (1) to be stimulated by the distal electrode (203), wherein the atrioventricular conduction time of the stimulation is shorter than the inherent atrioventricular conduction time.

15. A method for providing cardiac resynchronization therapy to patients in need, the method comprising the steps of: a) using the proximal electrode (213) of the electrode (20) of an implantable medical device (22) for stimulating a human or animal heart (1), particularly the implantable medical device (22) according to any one of claims 1 to 15, to detect (500) the intrinsic atrial contraction of the heart (1) to be stimulated, or to stimulate (500) the atrium (2) of the heart (1) to be stimulated using the proximal electrode (213), wherein the proximal electrode (213) is implanted in the atrium (2) of the patient's heart (1); b) Detect (530) the intrinsic ventricular contraction of the heart (1) to be stimulated using the distal electrode polarity (203) of the electrode (20), wherein the distal electrode polarity (203) is implanted in the septum (13) of the patient's heart (1); c) Determine (530) i) the intrinsic atrioventricular conduction time between the intrinsic atrial contraction or the stimulation of the atrium and ii) the intrinsic ventricular contraction; d) Setting (550) the atrioventricular conduction time of stimulation of the ventricles (3, 5) of the patient's heart (1), wherein the atrioventricular conduction time of stimulation is shorter than the inherent atrioventricular conduction time; e) Stimulate (560) the ventricles (3, 5) of the patient’s heart with the distal electrode (203).

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