Dynamic control of heart failure treatment
阅读说明:本技术 心力衰竭治疗的动态控制 (Dynamic control of heart failure treatment ) 是由 戴维·J·特恩斯 喻映红 詹森·汉弗莱 大卫·L·佩什巴赫 迈克尔·詹姆斯·迪弗雷纳 亚当 于 2018-06-13 设计创作,主要内容包括:讨论了用于监视和处置患有心力衰竭(HF)的患者的系统。所述系统可以感测心脏信号,并且接收关于患者生理状况或机能状况的信息。可以在许多患者生理状况或机能状况下创建包括房室延迟(AVD)或其他时序参数的推荐值的刺激参数表。所述系统可以周期性地重新评定患者生理状况或机能状况。治疗编程器电路可以在仅左心室起搏和双心室起搏之间动态地切换,或者基于患者状况在单部位起搏和多部位起搏之间切换。治疗编程器电路可以使用输入的心脏信号和存储的刺激参数表来调整AVD和其他时序参数。(Systems for monitoring and treating patients with Heart Failure (HF) are discussed. The system may sense cardiac signals and receive information about a physiological or functional condition of a patient. A stimulation parameter table including recommended values for atrioventricular delay (AVD) or other timing parameters may be created under a number of patient physiological or functional conditions. The system may periodically reassess the patient's physiological or functional condition. The therapy programmer circuit may dynamically switch between left ventricular only pacing and biventricular pacing, or between single site pacing and multi-site pacing based on patient conditions. The therapy programmer circuit may use the input cardiac signals and the stored stimulation parameter table to adjust AVD and other timing parameters.)
1, a system, comprising:
a stimulation control circuit configured to select parameters for use during cardiac stimulation from a set of stimulation parameters stored in a memory;
wherein the stored set of stimulation parameters includes timing parameters corresponding to a plurality of heart rates or heart rate ranges for each of Atrial Sensing (AS) events and Atrial Pacing (AP) events;
wherein the selected parameters include timing parameters corresponding to the sensed heart rate and an indication of an AS or AP event; and is
Wherein at least portions of the stored set of stimulation parameters are dynamically updated using atrioventricular conduction characteristics.
2. The system of claim 1, wherein the stimulation control circuit is configured to store a stimulation parameter table in the memory, the stimulation parameter table including timing parameters for AS events and AP events and corresponding to the plurality of heart rates or heart rate ranges.
3. The system of any of claims 1-2, wherein the timing parameters stored in the memory include atrioventricular delay (AVD) values.
4. The system of claim 3, wherein the stimulation control circuitry is configured to determine the AVD value using or more of a interval between atrial activation and left ventricular sensing events and a second interval between atrial activation and right ventricular sensing events.
5. The system of of any of claims 3-4, wherein the stimulation control circuitry is configured to further use an intraventricular interval between a left ventricular sense event and a right ventricular sense event to determine an AVD value.
6. The system of any of , wherein the stimulation control circuitry is configured to determine the AVD value further steps using a time offset between a th sensed event at a ventricular sensing site and a second sensed event at a ventricular pacing site different from the ventricular sensing site.
7. The system of any of claims 1-6, wherein the timing parameters stored in the memory include atrioventricular delay (VVD) values.
8. The system of of any of claims 1-7, wherein timing parameters stored in the memory further steps correspond to various times of days, and the stimulation control circuitry is configured to select parameters used during cardiac stimulation that further steps correspond to times of days.
9. The system of any of claims 1-8, wherein the timing parameters stored in the memory further steps correspond to patient posture and the stimulation control circuitry is configured to select parameters used during cardiac stimulation that further steps correspond to the received patient posture.
10. The system of of claims 3-6, wherein the stimulation control circuitry is configured to determine or update a stored timing parameter using a stored second or more timing parameters, wherein the timing parameter corresponds to a th heart rate or heart rate range, the stored second or more timing parameters each corresponding to a heart rate or heart rate range different from the th heart rate or heart rate range.
11. The system of any of claims 1-10, , wherein the stimulation control circuitry is configured to dynamically update at least portions of the stored set of stimulation parameters using intrinsic atrioventricular spacing.
12. The system of claim 11, wherein the stimulation control circuitry is configured to dynamically update at least the portion of the stored set of stimulation parameters using the patient's cardiac response or hemodynamic response to cardiac stimulation.
A system of , comprising:
a stimulation control circuit that selects parameters for use during cardiac stimulation from a set of stimulation parameters stored in a memory;
wherein the stored set of stimulation parameters includes stimulation site parameters corresponding to a plurality of heart rates or heart rate ranges for Atrial Sensing (AS) events and Atrial Pacing (AP) events;
wherein the selected parameters include stimulation site parameters corresponding to the sensed heart rate and an indication of an AS or AP event; and is
Wherein at least portions of the stored set of stimulation parameters are dynamically updated using atrioventricular conduction characteristics.
14. The system according to claim 13, wherein stimulation site parameters stored in the memory include an indication of Left Ventricular (LV) only pacing or Biventricular (BiV) pacing.
15. The system of of any of claims 13-14, wherein the stimulation site parameters stored in the memory include an indication of single site left ventricular pacing (SSP) or biventricular pacing (BiV).
Technical Field
This document relates generally to medical systems and devices, and more particularly, to electrical stimulation systems, devices, and methods for treating heart failure.
Background
Congestive Heart Failure (CHF) is the leading cause of death in the united states and globally. CHF occurs when the heart fails to adequately supply enough blood to maintain a healthy physiological state. CHF can be treated by drug therapy or by electrical stimulation therapy.
Implantable Medical Devices (IMDs) are used directly to monitor CHF patients and manage heart failure in ambulatory settings some IMDs may include sensors that sense physiological signals from the patient and detect worsening heart failure (such as heart failure decompensation). frequent patient monitoring and early detection of worsening heart failure may help improve patient outcome.
examples of electrical stimulation therapy are Cardiac Resynchronization Therapy (CRT). CRT may indicate CRT, which is typically delivered as Biventricular (BiV) pacing or synchronized Left Ventricular (LV) only pacing, for patients with moderate to severe symptoms and ventricular dyssynchrony.CRT maintains LV and RV pumping synchronously by sending electrical stimulation to both the LV and the Right Ventricle (RV). synchronized stimulation may improve cardiac pumping efficiency and increase blood flow in CHF patients.
Disclosure of Invention
Ambulatory Medical Devices (AMDs), such as IMDs, subcutaneous medical devices, wearable medical devices, or other external medical devices, may be used to detect worsening heart failure and deliver Heart Failure (HF) therapy to restore or improve cardiac function. The IMD may be coupled to implanted leads having electrodes that may be used to sense cardiac activity or deliver HF therapy, such as electrical cardiac stimulation. AMD can have functionality that enables programmable therapy of electrical stimulation parameters (such as stimulation cavity or site, stimulation pattern, or stimulation timing) that can be adjusted manually or automatically.
AMD can be configured to stimulate various heart chambers to restore cardiac synchrony and improve blood flow dynamics. During CRT or BiV pacing, synchronized stimulation may be applied to the LV and RV of the heart. RV and LV pacing sites may be stimulated simultaneously, or sequentially with RV-LV interventricular pacing delay (VVD). The delivery of LV and RV pacing may be timed relative to a reference point, such AS an intrinsic atrial depolarization sensed by an atrial electrode (atrial sense or AS), or an atrial pacing pulse (AP) that causes atrial activation. LV and RV pacing may be delivered at the end of an atrioventricular delay (AVD) if no intrinsic ventricular depolarization is detected within a time period of AVD following the AS or AP.
In contrast to BiV pacing, LV-only pacing may require a simpler implantable procedure, consume less power, and provide increased battery life.
In conventional Single Site Pacing (SSP), only sites (e.g., LV) in a particular chamber are stimulated, alternatively, multi-site pacing (MSP) may be used as an alternative to SSP.
Stimulation timing parameters (e.g., AVD, VVD, or ILVD) define the timing and sequence of cardiac stimulation and may have an impact on treatment efficacy and hemodynamic outcome. Stimulation timing parameters, such AS AVD, may be determined using measurements of patient AV conduction, such AS the interval measured from the surface Electrocardiogram (ECG) between P-waves and R-waves over a cardiac cycle (PRI), or the interval measured from an intracardiac Electrogram (EGM) between Atrial Sensing (AS) or Atrial Pacing (AP) events to ventricular sensing events (VS) over a cardiac cycle (AVI). In a patient, the PRI or AVI may not remain constant, but instead may vary under a number of physiological or functional conditions. For example, long-term changes in a patient's health condition, HF progression (such as remodeling or decompensation), or short-term changes in heart rate, posture changes, physical activity, sleep/awake state, medication, hydration, diet may affect PRI or AVI, among other factors. Thus, stimulation timing parameters (such as AVD) may also be affected by long-term or short-term changes in patient condition. Thus, HF therapy based on previously optimized AVD (e.g., LV-only pacing, BiV pacing, SSP, or MSP) may no longer be effective or provide satisfactory patient results under different patient conditions. For example, when a patient changes posture, the programmed AVD may be too long, causing CRT delivery to drop or be sub-optimal, which adversely affects patient outcome.
In addition to inter-patient differences in response to LV-only pacing to BiV pacing and response to MSP or MSP, there are also intra-patient variations over time in response to LV-only pacing or BiV pacing or response to SSP or MSP, at least because of the effects of long-term and short-term variations in patient physiological or functional conditions.
This document discusses, among other things, patient management systems for monitoring and treating patients with heart failure.A system may include a sensor circuit that senses cardiac signals and a receiver that receives information about a patient physiological or functional condition, such as posture and physical activity.A stimulation timing parameter at a specified patient physiological or functional condition may be determined and stored in memory.
This document provides technical solutions to the above-identified challenges in electrical stimulation therapy for HF, thus improving the medical techniques of device-based heart failure patient management, among other things, this document provides methods for providing cardiac pacing therapy tailored to individual patients or specific patient physiological or functional conditions (e.g., by programming therapy parameters including stimulation timing, stimulation site, and stimulation mode).
This document also discusses estimating the PRI or AVI during stimulation using the offset between the AVD and the PRI or AVI corresponding to a false fusion heartbeat. Because the estimation process does not require pacing to be suspended, adequate pacing therapy can be achieved even during therapy adjustments, and adverse effects on patient outcomes can be avoided or mitigated.
In addition to improvements in medical technology for device-based heart failure patient management in various patient conditions, the systems, devices, and methods discussed herein may also enable more efficient device memory usage, such as by storing and updating stimulation timing parameters that are clinically more relevant to patient long-term and short-term changing conditions. The personalized and dynamically adjusted therapy discussed in this document may not only improve therapy efficacy and patient outcome, but may also save device power and extend battery life. With personalized HF therapy tailored to a particular patient condition, less unnecessary interventions or hospitalizations can be scheduled, prescribed, or provided; as a result, overall cost savings may be realized.
Other aspects of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part hereof , each of which is not to be taken in a limiting sense.
Drawings
Various embodiments are illustrated by way of example in the figures of the accompanying drawings. Such embodiments are illustrative, and are not intended to be exhaustive or exclusive embodiments of the present subject matter.
FIG. 1 illustrates an example of a patient management system and portions of an environment in which the system may operate.
Fig. 2 illustrates an example of a dynamically controlled cardiac stimulation system configured to program and deliver electrical stimulation to treat HF or other cardiac disorders.
Fig. 3A-3B illustrate examples of stimulation parameter tables that include recommended values for stimulation timing for various patient physiological and physical conditions.
Fig. 4A-4B illustrate examples of methods for initializing and updating a stimulation parameter table.
Fig. 5 illustrates an example of a method for dynamically determining PRI or AVI during pacing.
Fig. 6 illustrates an example of a method for determining between LV-only pacing and BiV pacing.
Fig. 7 illustrates an example of a method for determining between SSP pacing and MSP.
Fig. 8 illustrates a block diagram of an example machine on which any or more of the techniques (e.g., methods) discussed herein may execute.
Detailed Description
Disclosed herein are systems, devices, and methods for monitoring and treating patients with heart failure or other cardiac disorders. The system may sense cardiac signals and receive information about a physiological or functional condition of a patient. A stimulation parameter table including recommended values for timing parameters (such as AVD) may be created under many patient physiological or functional conditions. The system may periodically reassess the patient's physiological or functional condition. The therapy programmer circuit may dynamically switch between LV-only pacing and BiV pacing, switch between single-site pacing and multi-site pacing based on patient conditions, or adjust stimulation timing using an input cardiac signal and a table of stimulation parameters. HF therapy can be delivered according to the determined stimulation site, stimulation pattern, and stimulation timing.
System and apparatus for HF monitoring and treatment
Fig. 1 illustrates an example of a
The IMD110 may include a hermetically sealed can 112, the hermetically sealed can 112 may contain electronic circuitry that may sense physiological signals in the
The
The electrodes from or more of the leads 108A-C may be used with the canister housing 112 , such as for unipolar sensing of EGMs or for delivery of 0 or more pacing pulses, for example, defibrillation electrodes from the lead 108B may be used with the canister housing 112 1, such as for delivery of or more cardioversion/defibrillation pulses, in examples, the IMD110 may sense impedances between or more electrodes disposed in the leads 108A-C or on the canister housing 112, the IMD110 may be configured to inject currents between electrodes , sense voltages thus generated between the same or different pairs of electrodes, and use the electrodes to determine impedances in a bipolar configuration, or a bipolar configuration, the same pair of electrodes , or different pairs of electrodes, and use the electrodes to sense impedance from a common electrode pair, or a plurality of electrodes for intra-cardiac pressure sensing, intra-cardiac pressure or intra-cardiac pressure, or cardiac pressure, and may be used in a variety of cardiac pulse sensing electrodes, or cardiac pulse, the same cardiac pressure, or cardiac pulse, the same physiological signals, and may be sensed from a plurality of electrodes, or cardiac pressure sensing electrodes, or cardiac pressure sensors 110, or cardiac pressure sensing, or cardiac pressure sensing, or cardiac pressure, such as an example, or cardiac pressure sensor, or cardiac pressure sensing, or cardiac pressure sensing, or cardiac pressure.
In some examples,
The arrangement and function of these leads and electrodes are described above by way of example and not by way of limitation. Other arrangements and uses of these leads and electrodes are possible depending on the needs of the patient and the capabilities of the implantable device.
The
The
The
The dynamically controlled
Such general-purpose circuitry may include a microprocessor or portion thereof, a microcontroller or portion thereof, or programmable logic circuitry, or portion thereof, "comparator" may include, for example, an electronic circuit comparator that may be configured to perform a particular function of a comparison between two signals, or a comparator may be implemented as a portion of general-purpose circuitry that may be driven by code instructing a portion of the general-purpose circuitry to perform a comparison between two signals, among others.
Fig. 2 illustrates an example of a dynamically controlled
Additionally or alternatively, the cardiac signal may comprise a signal indicative of cardiac mechanical activity or a patient hemodynamic state. In an example, the cardiac signal may include a signal sensed from an accelerometer or a microphone configured to sense heart sounds in the patient. In an example, the cardiac signal may include a cardiac or thoracic impedance signal. The cardiac mechanical signal may comprise a blood pressure sensor signal or any other sensor signal indicative of a cardiac mechanical activity or a hemodynamic state.
In examples,
The
The
In examples, the
The
Therapy programmer circuit 230 may include a circuit group including or more other circuits or sub-circuits including or of these or more other circuits or sub-circuits that may perform functions, methods, or techniques described herein, either individually or in combination, the hardware of the circuit group may be designed to perform certain operations (e.g., hardwired), in examples, the hardware of the circuit group may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) that include computer readable media that are physically modified (e.g., magnetically, electrically movable placement of particles of constant mass, etc.) to encode instructions of certain operations, in examples, the hardware of the circuit group may include computer readable media that are physically modified (e.g., magnetically, electrically movable placement of particles of constant mass, etc.) to encode instructions of certain operations, in connecting physical components, the basic electrical properties of the hardware composition change, e.g., from an insulator to an insulator, or vice versa, so that when a second circuit group of circuits or sub-circuits is connected to a different circuit group of circuits, such as a circuit component , which may be repeatedly loaded at more than when the second circuit group of circuits or sub-circuits is connected with a different circuit components, such as a circuit group of hardware , which may be repeatedly loaded at times, which the second circuit components may be added, such as a computer readable media, which may be added, such as a computer readable media, where the operations are added, where the operations of circuit group of circuits, such as a circuit group of circuits 3578, where the operations are added, where the operations of circuits, may be added, where the operations of circuits, where the operations may be added, where the operations of the operations may be added.
In an example, the stimulation
The MSP may be delivered at one or more heart chambers or at two or more sites inside tissue surrounding any of these chambers or on the epicardial surface of these heart chambers or tissue during MSP, pulse trains may be delivered at two or more heart sites sequentially, either simultaneously or with an intra-ventricular delay that is less than the sensed or paced time interval value of the heart cycle.
In an example, the stimulation
The stimulation
The AVD may be determined AS a linear combination of the interval between Atrial Sensing (AS) or Atrial Pacing (AP) activation to sensing RV activation (RVs) and the interval between AS or AP to sensing LV activation (LVs). Alternatively, AVD values for various patient conditions may be dynamically created and stored in the
The PRI/
The PRI/
Additionally or alternatively, the
In examples, the
The
The
The
Pacing optimization for patient condition indication
3A-3B illustrate examples of a stimulation parameter table that includes recommended values for stimulation timing for various patient physiological and physical conditions, examples of such conditions may include posture (e.g., supine, sitting, standing, or transitioning between postures, among other postures), walking, running, sleep, time in days (e.g., day, night, or a particular duration during days), diet, hydration, drug therapy intake, heart rate variability, arrhythmic events (e.g., atrial fibrillation, ventricular tachycardia, premature ventricular contraction, post-arrhythmia), atrial activation patterns (e.g., atrial pacing or atrial sensing), which conditions, individually or in combination, may affect cardiac tissue properties and patient hemodynamics.
For example, and without limitation, table 300 may include stimulation timing values such AS AVD values in a particular Heart Rate (HR)310,
In various examples, at least entries of tables 300 or 350 may additionally or alternatively include recommended values of stimulation timing parameters other than AVD in examples, the table entries may include recommended RV-LV delays (VVD) for corresponding patient conditions of heart rate, posture and atrial activation mode, the VVD representing an offset between LV pacing pulses and RV pacing pulses for BiV pacing or CRT therapy (such as selected by a system user or determined by stimulation site selector circuit 231) within a heart cycle, in examples the VVD may be set to zero such that LV pacing and RV pacing are delivered simultaneously, in another examples, at least table entries may include a recommended intra-LV time offset (ILVD) representing an offset between LV pacing pulses delivered separately at different LV sites within a heart cycle when the LV MSP is selected by the system user or determined by stimulation
In an example, at least entries of the table 300 or 350 may additionally or alternatively include information about a stimulation site (such AS an indication of LV-only pacing or BiV pacing) or information about a stimulation mode (such AS an indication of SSP or MSP), AS discussed above with reference to fig. 2, the selection between LV-only pacing or BiV pacing, SSP, or MSP may vary under different patient physical and physiological conditions.
In examples, multiple tables of stimulation timing parameter values may be constructed and stored in the
Fig. 4A-4B illustrate a method for initializing and updating a stimulation parameter table, such as tables 300 or 350. The table initialization and update method may be implemented in the
The measurement of PRI or AVI during PRI or atrial pacing AP during atrial sensing AS may include sensing ventricular responses at or more of RV sensing (RVS) sites or LV sensing (LVS) sites, such AS by using RV sensing vectors including RV electrodes (e.g., of 152-154) or LV sensing vectors including LV electrodes (e.g., of 161-164) for sensing ventricular responses at or more of LVAP sites.
At 413, the PRI or AVI measurements, or optionally along with other information acquired at 412, may be used to calculate one or more stimulation timing parameters, such as AVD.
AVD=k1*AVR+k2*AVL+k3 (1)
In equation (1), AVRIndicating the interval between AS or AP and RVS, AVLIndicating the spacing between the AS or AP to the LVS. In the example, if the intraventricular interval between the RV and LV is ΔLR=AVL-AVRLess than zero, then only AV may be usedLTo calculate the AVD, i.e., AVD k2 AVL. In the example, k2 is approximately between 0.5 and 1. If ΔLREqual to or greater than zero, as given in equation (1) above, can be in accordance with AVRAnd AVLTo calculate the AVD. The weight factors k1 and k2 and the scalar bias k3 may be selected according to the synchronicity of LV and RV sensing. In an example, the weighting factors may be determined empirically using pacing data from a patient population, data obtained from echocardiographic studies, or other clinical diagnoses. In an example, weighting factors may be generated separately and used to calculate AVDs for different ventricular stimulation sites (LV or BiV only) or for different LV lead locations (e.g., anterior LV or free wall).
In examples, the AVD computation may additionally include a heartbeat screening process.A sufficient number (e.g., 3-20) of LVS or RVS heartbeats during the AS that meet the sensing criteria are required to obtain a more reliable sensed AVDIn some examples, the AVD is determined using a median, mean, or other central trend over a number of PRI or AVI measurements, such as determined according to equation (1). in some examples, if there are not enough LVS or RVS heartbeats within a specified time or number of cardiac cycles, then the sensed AVD may be used to determine the AVD for pacingLRGreater than zero milliseconds (msec), it may be determined that the sensed AVD is approximately 60msec, longer than the sensed AVD. If ΔLREqual to or less than zero milliseconds, it can be determined that the sensed AVD is approximately 45msec longer than the sensed AVD.
Because the AVD is estimated using measurements from the RV or LV sensing electrodes, the estimated AVD may not be optimal when applied to a different RV or LV to deliver pacing therapy, at least because of the time offset (Δ) between cardiac activation at the sensing and pacing electrode sitesSP). Referring to FIG. 1, by way of example, and not limitation, sensing electrode LV1161 is used to measure AVL(AS or AP to LVS interval), while LV pacing is delivered via LV pacing vectors including a different electrode LV3163 and can 112. Sense-pace electrode time offset Δ between electrodes LV1 and LV3 may be measured under known patient conditionsSPAnd shifting the time by deltaSPApplication to other patient conditions. By way of example, and not limitation, Δ may be measured under relatively easily managed patient conditionsSPSuch as reduced rate limited (LRL) pacing when the patient is in a prone position. Measured deltaSPMay be stored in the
At 414, if it is determined that the RV or LV sensing electrode is different from the RV or LV pacing electrode, then at 415, a Δ time offset may be added by adding a sense-pacing electrode time offsetSPTo correct AVD in various patient conditions including and under which Δ is determinedSPCan be easily managed.At 416, a corrected AVD may be added to the stimulation parameter table if, at 414, the same ventricular electrode is used for ventricular sensing and ventricular pacing, then no AVD correction is required, at 416, the AVD calculated at 413 may be added to the stimulation parameter table in examples, the conditions under which the AVD is calculated may be screened against corresponding interaction limits for the conditions, such AS HR range, patient posture, atrial activation mode (e.g., AS or AP), or time of day AS shown in FIGS. 3A-3B.
FIG. 4B is a flow chart 420 illustrating a method of updating a stimulation parameter table (such as a table created using method 410). The table may be updated periodically at specified times, such as every minutes, every few minutes, every hours, every day, every specified few days, every week, every month, etc. in examples, a table update history (such as a trend of table updates) may be used to determine the frequency of table updates.
The update of the stimulation parameter table may be performed on the entire table or portions of the table, such as those table entries corresponding to specific conditions (e.g., standing postures). The frequency of table updates may be varied for different portions of the table such that the update frequency of the portion of the table may be higher than another portions of the table.
Additionally or alternatively, table updates may be triggered by specific events. At 421, trigger events for table updates are monitored, including, for example, volume (e.g., percentage) of pacing therapy patients received during a specified time period, heart failure exacerbation or decompensation events, hemodynamic response to CRT, occurrence of heart rate, posture, physical activity, heart sounds, intrinsic heart beat, sudden large changes in AVD recommendations, among others. In an example, the table update frequency may be determined based on variability of PRI or AVI in a specified patient condition. In an example, a variance, standard deviation, range, or other spread measure may be calculated from multiple PRIs or AVIs for a particular patient condition. A higher PRI variability (such as when a specified threshold is exceeded) may indicate irregular AV conduction and less efficient cardiac function in a particular patient condition. This may trigger the assessment and updating of the stimulation parameter table.
If at 422, one or more trigger events occur and a particular condition is met (e.g., exceeds a threshold or falls within a specified range of values), at 423, the patient physiological or functional condition may be assessed to determine whether they continue to affect the patient cardiac or hemodynamic response.
Updating of table entries such as AVDs or other stimulation timing parameters requires sensing RV or LV activity (RVs or LVs, respectively) and measuring PRI or AVI. Typically, this may require at least temporary suspension of ventricular pacing therapy. This may be disadvantageous because stopping pacing even for short periods of time may cause detrimental patient outcomes. To ensure uninterrupted pacing during table updates, methods of dynamic PRI or AVI determination may be used, such as the method discussed below with reference to fig. 5. PRI or AVI may be estimated and the stimulation parameter table may be updated without the need to pause pacing therapy or otherwise compromise ongoing pacing therapy.
PRI/AVI determination at pacing
Fig. 5 illustrates a
In another examples, the AVD may start from a large initial value that is greater than the PRI and gradually decrease at a specified step sizeA unique morphology. If the morphology indicates that false fusion has occurred at 513, then from the superimposed waveform morphology, the personalized offset ΔI-PFCan be measured as AVDPFAnd intrinsic PRI, that is, DeltaI-PF=PRI-AVDPFWherein, AVDPFAvd indicating induction of false fusion if no false fusion occurs at 513, avd may continue to be adjusted at 511 in examplesI-PFAnd may be in the range of between about 10-15 msec. Offset deltaI-PFMay be stored in the
Processing of dynamic PRI or AVI determination may begin at 520, and at 520 PRI estimation during pacing therapy (such as CRT or MSP) may be triggered periodically. Events that trigger PRI estimation may include, among other things, stimulation parameter table updates, stimulation site updates (e.g., switching between LV-only pacing and BiV pacing), or stimulation pattern updates (e.g., switching between SSP and MSP). At 530, the AVD of the current ongoing pacing therapy may be gradually increased, such as at a specified step size of about 5-10 msec. Ventricular pacing morphology may be monitored during increasingly longer pacing of the AVD. If a false fusion morphology is detected at 540, the AVD adjustment process may be terminated and the current AVD, AVD corresponding to the false fusion may be recordedPF'. Note that AVDPF' is measured under current patient conditions, which may differ from the AVD determined at 513 belowPFAnd ΔI-PFThe condition of the patient. At 550, AVD may be usedPF' and stored offset ΔI-PFTo estimate the estimated PRI, ePRI:
ePRI=AVDPF’+ΔI-PF(2)
estimation of PRI according to (2) assumes ΔI-PFSubstantially unaffected by changing patient conditions. Because the AVD expansion at 530 stops at the false fusion (at this point, pacing therapy is still being delivered) and never exceeds that point, pacing therapy can be effectively maintained during the PRI determination process. In addition, a pre-stored Δ is usedI-PFIt is also possible to shorten the time for PRI or AVI calculation, save battery power, and save computational resources.
As will be discussed with reference to FIG. 6, the estimated PRI or AVI may be used to update stimulation timing parameters, such as AVD, according to equation (1), or to re-assess and select stimulation sites between LV-only pacing and BiV pacing under various patient physiological or functional conditions.
Dynamic stimulation site switching between LV-only pacing and BiV pacing
Fig. 6 illustrates an example of a
The
If the heart rate criteria are met at 630, then the measured PRI may be compared to a PRI threshold (PRI) at 640TH) A comparison is made. In an example, PRITHApproximately in the range between 250-THSuch as by using electrocardiographic data or other heart failure diagnosis. PRITHMay be patient condition-related such that the PRI is of patient conditionsTHMay differ from PRI in another different patient conditionsTH. In an example, PRITHMay be heart rate related. PRI under Lower Rate Limiting (LRL) of devicesTHCan be set to a value of , such as about 270 msec. PRI at the Maximum Tracking Rate (MTR) of the deviceTHMay be set to a lower value, such as about 200 msec. PRI at Heart Rate between LRL and MTRTHMay be interpolated between 200msec and 270msec by using a linear curve, a piecewise linear curve, an exponential curve, or other non-linear curve. If the PRI exceeds a threshold PRI indicative of patient conditionTHThen BiV pacing is recommended at 650.
If the PRI does not exceed the threshold PRITHThen at 660, variability of the PRI can be evaluated. Variability may be measured using variance, standard deviation, range, or other spread measures from multiple PRIs or AVIs in a given patient condition. If at 660, PRI variability exceeds the PRI variability threshold PRIVAr indicated by the patient's conditionTHThen BiV pacing is recommended at 650. A more variable PRI may indicate irregular AV conduction and cardiac functional degradation, in which case BiV pacing may be superior to LV-only pacing for providing enhanced synchronized ventricular contraction and improved cardiac performance. If the PRI is not substantially lengthened (e.g., reduced to a threshold PRI)THBelow) and less variability (e.g., drop)To a change threshold PRIVArTHBelow), then at 670 LV-only pacing may be recommended.
Alternatively, PRI and PRI variability may be analyzed over a plurality of N heartbeats to improve reliability of the PRI and PRI variability measurements, where N is a positive integer, N is between 10 heartbeats and 20 heartbeats, N heartbeats may be continuous heartbeats, alternatively, N heartbeats may be discontinuous, for example, heartbeats are sensed every 5-15 seconds, PRI is calculated from the heartbeats, and the decision at which N PRI's 640 and 660 may be calculated from N heartbeats may be based on at least M of the N heartbeats showing PRI extension (at 640) or increased variability (at 650) in the example, M is equal to or greater than 50% of N in the example, in another examples, LV-only or BiV pacing decisions may be evaluated over a plurality of N heartbeats.
In examples, information about the LV lead location may be included in
Dynamic stimulation mode switching between SSP and MSP
Fig. 7 illustrates an example of a
The
At 730, a trigger event is detected. The triggering event may include a change in a physiological or functional condition of the patient, such as a change in posture, a change in intensity of physical activity, or a chronic change in the HF status of the patient (such as a decompensation event). In an example, the triggering event includes an increase in heart rate. Stimulation site assessment may be triggered if X out of Y beats exceed a heart rate threshold. In an example, a rate cut-off of three heartbeats over 100bpm out of five consecutive heartbeats may trigger stimulation site assessment. Alternatively, stimulation site assessment may be performed periodically at designated times.
If heart rate criteria are met at 730, then at 740, a stimulation pattern assessment is triggered and each of the interventricular intervals { D (i) } corresponding to the LV site { LV (i) } may be compared to an interventricular delay threshold DTHA comparison is made. In an example, the threshold D may be determined for various patient conditionsTHSuch as by using electrocardiographic data or other heart failure diagnosis. Threshold value DTHMay be patient condition dependent such that the threshold D for patient conditionsTHMay differ from PRI in another different patient conditionsTH. If the corresponding inter-ventricular interval D (i) exceeds a threshold DTHThen the LV site (such as LV (i)) is selected for delivering pacing. For example, because of the threshold value DTHIf, at 740, two or more LV sites satisfy the interventricular interval criteria, then, at 760, LV electrodes at these LV sites are selected for delivery of msp, if only LV sites satisfy the interventricular interval criteria, then, at 750, SSP using the LV electrodes at the site is recommended, if no LV sites satisfy the interventricular interval criteria, then, at 750, SSP using the LV electrode corresponding to the longest interventricular interval among the candidate LV sites { LV i (j) }.
Non-transitory machine-readable medium
Fig. 8 illustrates a block diagram of an
In an alternative embodiment, the
In an example, the hardware of a circuit group may be designed to perform certain operations (e.g., hardwired) either individually or in combination at the time of operation, in an example, the hardware of a circuit group may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) that include instructions that are physically modified (e.g., of a constant mass of particles, magnetically, electrically, movably placed, etc.) to encode certain operations, in an example, the hardware of a circuit group may include computer readable media that are physically modified (e.g., of a constant mass of particles, magnetically, electrically, movably placed, etc.) to encode certain operations, in connecting physical components, the electrical properties of the basis of the hardware components are changed, e.g., from an insulator to a conductor, or vice versa, so that the circuit components may be loaded at more than a second time for execution unit, such as a second operation unit, or a third operation unit, such as a third operation unit, or a fourth operation unit, such as a third operation unit, such as an operation unit, a fourth operation unit, a fifth operation, a sixth operation unit, a fifth operation unit, a sixth operation, a fifth operation, a sixth operation, a fifth operation, a sixth operation, a fifth operation, a sixth operation, a fifth operation, a sixth operation.
The machine (e.g., computer system) 800 may include a hardware processor 802 (e.g., a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a hardware processor core, or any combination thereof), a main memory 804, and a static memory 806, some or all of which may communicate with each other via an intermediate link (e.g., a bus), the machine 800 may further include a display unit 810 (e.g., a raster display, a vector display, a holographic display, etc.), an alphanumeric input device 812 (e.g., a keyboard), and a User Interface (UI) navigation device 814 (e.g., a mouse), in examples, the display unit 810, the input device 812, and the UI navigation device 814 may be a touch screen display, the machine 800 may additionally include a storage device (e.g., a drive unit) 816, a signal generation device 818 (e.g., a speaker), a network interface device 820, and one or more sensors 821, such as a Global Positioning System (GPS) sensor, compass, accelerometer, or other sensor, the machine 800 may include an output controller 828 such as a communication or control or peripheral devices (e.g., a serial connection, a USB, a printer, e.g., a serial connection, a USB, a wireless connection, or other connection (e.g., a serial connection, such as a USB, a.
The
While the machine-
The term "machine-readable medium" may include any medium that is capable of storing, encoding or carrying instructions for execution by the
The instructions 824 may be further sent or received over a communication network 826 by using a transmission medium via a network interface device 820, the network interface device 820 utilizing any of a number of transfer protocols (e.g., frame relay, Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), hypertext transfer protocol (HTTP), etc.)A domain network (LAN), domain network (WAN), a packet data network (e.g., the internet), a mobile telephone network (e.g., a cellular network), a Plain Old Telephone (POTS) network, and a wireless data network (e.g., known as a "plain old" telephone networkIs known as the Institute of Electrical and Electronics Engineers (IEEE)802.11 family of standards
The IEEE802.16 family of standards), the IEEE 802.15.4 family of standards, peer-to-peer (P2P) networks in examples, the network interface device 820 may include or more physical jacks (e.g., ethernet jacks, coaxial jacks, or telephone jacks) or or more antennas connected to the communication network 826 in examples, the network interface device 820 may include multiple antennas for wireless communication using at least of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) technologies.or more features from or more of these embodiments can be combined to form other embodiments.
Some examples of the methods described herein may include machine-readable or machine-readable media encoded with instructions operable to configure an electronic device or system to perform methods as described in the above examples.
The above detailed description is intended to be illustrative, and not restrictive. The scope of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
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