阅读说明：本技术 动态房室延迟优化 (Dynamic atrioventricular delay optimization ) 是由 安琪 喻映红 于 2019-11-25 设计创作，主要内容包括：讨论了一种监视和治疗心力衰竭患者的系统和方法。该系统可接收不同心率或不同患者状况下的房室(AV)传导特性。包括刺激定时参数的刺激参数可存储在存储器中。该系统可以包括刺激控制电路,该刺激控制电路被配置为使用患者AV传导特性确定指示出要更新刺激参数所位于的定时的参数更新调度表,并且在确定出的参数更新调度表中动态地更新所存储的刺激参数集合的至少一部分。针对指定的心率或心率范围可以从刺激参数的集合中选择刺激参数以便在心脏刺激期间使用。(A system and method of monitoring and treating heart failure patients is discussed. The system may receive Atrioventricular (AV) conduction characteristics at different heart rates or under different patient conditions. Stimulation parameters including stimulation timing parameters may be stored in memory. The system may include a stimulation control circuit configured to determine a parameter update schedule using the patient AV conduction characteristics indicating timings at which stimulation parameters are to be updated, and to dynamically update at least a portion of the stored set of stimulation parameters in the determined parameter update schedule. Stimulation parameters may be selected from a set of stimulation parameters for a specified heart rate or heart rate range for use during cardiac stimulation.)

1. A medical device system, comprising:

a stimulation control circuit configured for delivering cardiac stimulation signals to a patient according to a set of stimulation parameters:

determining a parameter update schedule using atrioventricular conduction characteristics of the patient indicating timings at which at least a portion of the set of stimulation parameters is to be updated; and

at least a portion of the set of stimulation parameters is dynamically updated according to the determined timing.

2. The system of claim 1, wherein the stimulation control circuitry is configured to dynamically update at least one of a stimulation timing parameter, a number of stimulation electrodes, or a stimulation pattern of the cardiac stimulation signals.

3. The system of claim 2, wherein the stimulation mode of the cardiac stimulation signal includes at least one of a left ventricular only pacing mode or a biventricular pacing mode.

4. The system according to any one of claims 1-3, wherein the stimulation control circuitry is configured to select stimulation parameters from the set of stimulation parameters for a specified heart rate or heart rate range for use by the patient during cardiac stimulation.

5. The system according to any one of claims 2-4, comprising:

a receiver circuit configured to receive atrioventricular conduction information of a patient; and

a stimulator circuit configured to deliver cardiac stimulation using the selected stimulation parameters,

wherein the stimulation control circuitry is configured to determine atrioventricular conduction characteristics of the patient using the received atrioventricular conduction information.

6. The system of any of claims 2-5, wherein the stimulation timing parameter comprises an atrioventricular delay (AVD) value and the atrioventricular conduction characteristic comprises an intrinsic atrioventricular interval (AVI).

7. The system of any one of claims 2-6, wherein the stimulation control circuit is configured to determine the parameter update schedule using a measure of variability of the atrioventricular conduction characteristics.

8. The system of claim 7, wherein the parameter update schedule includes a parameter update frequency, an

Wherein the stimulation control circuitry is configured to decrease the parameter update frequency corresponding to a heart rate or a range of heart rates if the measure of variability of the atrioventricular conduction characteristic values is below a variability threshold and to increase the parameter update frequency if the measure of variability of the atrioventricular conduction characteristic values is above the variability threshold.

9. The system according to any one of claims 2-8, wherein the stimulation control circuitry is configured to:

determining values of atrioventricular conduction characteristics corresponding to a plurality of heart rates; and

a parameter update schedule is determined using a measure of covariance between the determined values of the atrioventricular conduction characteristic and the corresponding plurality of heart rates.

10. The system of claim 9, wherein the covariance metric is a correlation, the parameter update schedule comprises a parameter update frequency, and wherein the stimulus control circuit is configured to decrease the parameter update frequency if the correlation is below a correlation threshold and increase the parameter update frequency if the correlation is above the correlation threshold.

11. The system of claim 9, wherein the covariance measure is a rate of change of the atrioventricular conduction characteristic with respect to a change in heart rate, the parameter update schedule comprising a parameter update frequency, and wherein the stimulus control circuit is configured to decrease the parameter update frequency if the rate of change of the atrioventricular conduction characteristic is below a rate threshold and increase the parameter update frequency if the rate of change of the atrioventricular conduction characteristic is above the rate threshold.

12. The system according to any one of claims 2-11, wherein the stimulation control circuitry is configured to determine the parameter update schedule further using information of one or more of:

cardiac arrhythmia;

cardiac conduction abnormalities; or

Physical activity.

13. The system according to any one of claims 2-12, wherein the stimulation control circuitry is configured to:

measuring the atrioventricular conduction characteristic at the determined parameter update schedule; and

dynamically updating at least a portion of the stimulation timing parameters using the measured atrioventricular conduction characteristics.

14. The system of claim 13, wherein the dynamic update of at least a portion of the stimulation timing parameters comprises: a weighted combination of historical stimulation timing parameter values and the measured atrioventricular conduction characteristics, each scaled by a respective weighting factor.

15. The system according to any one of claims 1-14, wherein the stimulation control circuitry is configured to store a set of stimulation timing parameters for each of a plurality of heart rates or heart rate ranges in memory.

Technical Field

This document relates generally to medical systems and devices, and more particularly, to systems, devices, and methods of electrical stimulation for treating heart failure.

Background

Congestive Heart Failure (CHF) is a major 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 may be treated by drug therapy or electrical stimulation therapy (e.g., cardiac pacing).

Implantable Medical Devices (IMDs) have been used to monitor CHF patients and manage heart failure in a ambulatory environment. Some IMDs may include sensors to sense physiological signals from a patient and detect heart failure exacerbations, such as heart failure decompensation. Frequent patient monitoring and early detection of worsening heart failure may help to improve patient prognosis. Identifying patients at increased risk for future heart failure events may be helpful in providing timely treatment and preventing or reducing hospitalization. Identifying and safely managing patients at risk for worsening heart failure may avoid unnecessary medical intervention, hospitalization, and reduce healthcare costs.

An IMD may include a pulse generator and circuitry configured to electrically stimulate the heart or other excitable tissue to help restore or improve cardiac performance, or correct arrhythmias. One example of electrical stimulation therapy is Cardiac Resynchronization Therapy (CRT). CRT, typically delivered as Biventricular (BiV) pacing or synchronized Left Ventricular (LV) only pacing, may be applicable to CHF patients with moderate to severe symptoms and ventricular dyssynchrony. CRT keeps the LV and Right Ventricle (RV) pumping blood synchronously by sending electrical stimulation to both the LV and RV. Synchronous stimulation may improve cardiac pumping efficiency and increase blood flow in some CHF patients. CRT can reduce hospitalization and morbidity associated with worsening heart failure and improve quality of life.

Disclosure of Invention

This document discusses, among other things, a patient management system for monitoring and treating heart failure patients. The system may receive information of Atrioventricular (AV) conduction characteristics of a patient, such as at different heart rates or patient conditions. Stimulation parameters, including stimulation timing parameters such as atrioventricular delay (AVD) values, may be stored in memory. The system may include a stimulation control circuit configured to determine a parameter update schedule (schedule) using the received information of AV conduction characteristics, the parameter update schedule indicating timings at which at least a portion of the set of stimulation parameters is to be updated, and to dynamically update at least a portion of the stored set of stimulation parameters at the determined parameter update timings. For a specified heart rate or heart rate range, stimulation parameters such as AVD values may be selected from a set of stored stimulation parameters for use during cardiac stimulation.

Example 1 is a medical device system, comprising a stimulation control circuit configured to: determining a parameter update schedule using the atrioventricular conduction characteristics of the patient, the parameter update schedule indicating a timing at which the stimulation parameters are to be updated; dynamically updating at least a portion of a set of stimulation parameters of the patient stored in memory that includes stimulation timing parameters at the determined parameter update timing; and selecting, for a specified heart rate or heart rate range, stimulation parameters from a set of stimulation parameters for use during cardiac stimulation.

In example 2, the subject matter of example 1 optionally includes: a receiving circuit configured to receive atrioventricular conduction information of a patient, and a stimulator circuit configured to deliver cardiac stimulation using selected stimulation parameters. The stimulation control circuit may be configured to determine an atrioventricular conduction characteristic of the patient using the received atrioventricular conduction information.

In example 3, the subject matter of any one or more of examples 1-2 optionally includes stimulation timing parameters, which may include atrioventricular delay (AVD) values, and atrioventricular conduction characteristics include intrinsic atrioventricular intervals (AVIs).

In example 4, the subject matter of any one or more of examples 1-3 optionally includes stimulation control circuitry that can be configured to use the measure of variability of the atrioventricular conduction characteristic to determine the parameter update timing.

In example 5, the subject matter of example 4 can optionally include parameter update timing, which can include parameter update frequency. The stimulation control circuitry may be configured to decrease the parameter update frequency corresponding to the heart rate or range of heart rates if the measure of variability of the atrioventricular conduction characteristic values is below a variability threshold, and to increase the parameter update frequency if the measure of variability of the atrioventricular conduction characteristic values is above the variability threshold.

In example 6, the subject matter of any one or more of examples 1-5 optionally includes stimulation control circuitry configurable to: determining values of atrioventricular conduction characteristics corresponding to a plurality of heart rates; and determining parameter update timing using a measure of covariance between the value of the atrioventricular conduction characteristic and the corresponding plurality of heart rates.

In example 7, the subject matter of example 6 can optionally include the covariance measure, which can include a correlation, and the parameter update timing can include a parameter update frequency. The stimulation control circuit may be configured to decrease the parameter update frequency if the correlation is below a correlation threshold and increase the parameter update frequency if the correlation is above the correlation threshold.

In example 8, the subject matter of example 6 optionally includes a covariance metric, which may include a rate of change of atrioventricular conduction characteristics with respect to heart rate changes. The parameter update timing may include a parameter update frequency. The stimulation control circuit may be configured to: the parameter update frequency is decreased if the rate of change of the atrioventricular conduction characteristic is below a rate threshold, and the parameter update frequency is increased if the rate of change of the atrioventricular conduction characteristic is above the rate threshold.

In example 9, the subject matter of any one or more of examples 1-8 optionally includes the stimulation control circuitry may be configured to determine the parameter update timing further using information of one or more of cardiac arrhythmia, cardiac conduction abnormality, or physical activity.

In example 10, the subject matter of any one or more of examples 1-9 optionally includes stimulation control circuitry that may be configured to measure atrioventricular conduction characteristics at the determined parameter update timing and to dynamically update at least a portion of the stimulation timing parameters using the measured atrioventricular conduction characteristics.

In example 11, the subject matter of example 10 optionally includes dynamic updating of at least a portion of the stimulation timing parameters, which may include a weighted combination of historical stimulation timing parameter values and measured atrioventricular conduction characteristics, each scaled by a respective weighting factor.

In example 12, the subject matter of example 11 optionally includes stimulation control circuitry configurable to adjust the one or more weighting factors using information of physical activity of the patient.

In example 13, the subject matter of any one or more of examples 1-12 optionally includes stimulation control circuitry configurable to store, in memory, a set of stimulation timing parameters for each of a plurality of heart rates or heart rate ranges.

In example 14, the subject matter of example 13 optionally includes the stimulation control circuitry may be configured to store in the memory a stimulation parameter table including the set of stimulation timing parameters and the corresponding plurality of heart rates or heart rate ranges.

In example 15, the subject matter of any one or more of examples 1-14 optionally includes stimulation control circuitry configurable to: generating and storing in memory a regression model between (1) atrioventricular conduction characteristic values corresponding to a plurality of heart rates or heart rate ranges and (2) the plurality of heart rates or heart rate ranges; and using the generated regression model to estimate a value of an atrioventricular conduction characteristic at a particular heart rate; and dynamically updating at least a portion of the stimulation timing parameters using the estimated atrioventricular conduction characteristics.

Example 16 is a method of operating a system to control cardiac stimulation. The method comprises the following steps: determining a parameter update timing using atrioventricular conduction characteristics of the patient; dynamically updating at least a portion of a stimulation timing parameter set stored in memory that includes stimulation timing parameters at the determined parameter update timing; and selecting stimulation parameters from the set of stimulation parameters for use during cardiac stimulation for the specified heart rate or heart rate range.

In example 17, the subject matter of example 16 optionally includes a stimulation timing parameter, which may include an atrioventricular delay (AVD) value, and the atrioventricular conduction characteristic includes an intrinsic atrioventricular interval (AVI).

In example 18, the subject matter of any one or more of examples 16-17 optionally includes determining a parameter update timing, which may include using a measure of variability of atrioventricular conduction characteristics.

In example 19. The subject matter of any one or more of examples 16-18 optionally includes determining parameter update timing, which can include using a measure of covariance between (1) values of atrioventricular conduction characteristics corresponding to a plurality of heart rates and (2) the plurality of heart rates.

In example 20, the subject matter of any one or more of examples 16-19 optionally includes measuring the atrioventricular conduction characteristic at the determined parameter update timing. Dynamically updating at least a portion of the set of stimulation parameters, including using a weighted combination of: (1) the historical stimulation timing parameter values and the parameters and (2) the atrioventricular conduction characteristics measured at the determined parameter update timings, each scaled by a respective weighting factor.

In example 21, the subject matter of example 20 optionally includes adjusting the one or more weighting factors using information of physical activity of the patient.

In example 22, the subject matter of any one or more of examples 16-21 optionally includes delivering cardiac stimulation using the selected stimulation parameters.

Example 23 is a medical device system, comprising: a stimulation control circuit configured for delivering cardiac stimulation signals to a patient according to a set of stimulation parameters: determining a parameter update schedule using atrioventricular conduction characteristics of the patient indicating a timing at which at least a portion of the stimulation parameters are to be updated; and dynamically updating at least a portion of the set of stimulation parameters according to the determined time.

In example 24, the subject matter of example 23 optionally includes stimulation control circuitry configurable to dynamically update at least one of a stimulation timing parameter, a number of stimulation electrodes, or a stimulation pattern of cardiac stimulation signals.

In example 25, the subject matter of example 24 optionally includes a stimulation mode of the cardiac stimulation signal, which may include at least one of a left ventricular only pacing mode or a biventricular pacing mode.

In example 26, the subject matter of any one or more of examples 23-25 optionally includes stimulation control circuitry that may be configured to select stimulation parameters from a set of stimulation parameters for a specified heart rate or heart rate range for use by the patient during cardiac stimulation.

This summary summarizes some of the teachings of the present application and is not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details regarding the present subject matter may be found in the detailed description and appended claims. Other aspects of the 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 thereof, each of which should not be taken in a limiting sense. The scope of the invention is defined by the appended claims and their legal equivalents.

Drawings

Various embodiments are illustrated by way of example in the figures of the accompanying drawings. These embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present subject matter.

Fig. 1 shows an example of a patient management system and portions of an environment in which the system may operate.

Fig. 2 shows an example of a dynamically controlled cardiac stimulation system configured to generate personalized schedules for updating stimulation parameters and deliver cardiac stimulation to treat HF or other conditions.

Fig. 3 is a block diagram illustrating an example of a feature generator circuit configured to generate one or more features for determining a timing or frequency for updating stimulation parameters.

Fig. 4A-4C are diagrams illustrating examples of tables of stimulation parameters indicated by patient conditions for use in dynamic cardiac pacing.

Fig. 5 is a flow chart illustrating a method for updating stimulation parameters and delivering cardiac stimulation in accordance with the updated stimulation parameters.

Fig. 6 illustrates a block diagram of an example machine on which any one or more of the techniques (e.g., methods) discussed herein may be executed.

Detailed Description

An Ambulatory Medical Device (AMD), such as an IMD, subcutaneous medical device, wearable medical device, or other external medical device, may be used to detect heart failure exacerbations and deliver Heart Failure (HF) therapy to restore or improve cardiac function. The IMD may be coupled to an implantable lead having electrodes that may be used to sense cardiac activity, or deliver HF therapy, such as cardiac stimulation. AMD can have programmable therapy functions that allow for manual or automatic adjustment of electrical stimulation parameters, such as stimulation chambers or sites, stimulation patterns, or stimulation timing.

AMD can be configured to stimulate various heart chambers to restore cardiac synchrony and improve hemodynamics. During CRT or BiV pacing, simultaneous stimulation may be applied to the LV and RV of the heart. RV and LV pacing sites may be stimulated simultaneously or sequentially using 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 induces atrial activation. LV and RV pacing may be delivered at the end of an atrioventricular delay (AVD) if intrinsic ventricular depolarization is not detected within a period of AVD following the AS or AP.

In addition to BiV pacing, stimulation may also be delivered only at one heart chamber, such as the LV. LV-only pacing may improve cardiac synchrony in certain patients, such as those with intact Atrioventricular (AV) conduction, who require cardiac resynchronization. LV-only pacing may require simpler implantable surgery, consume less power, and provide increased battery life compared to BiV pacing. As such, it is a clinically effective alternative to more complex BiV treatment regimens. Similar to the timing of BiV pacing, if no intrinsic LV depolarization is detected within the period of the AVD, LV pacing may be delivered at the end of the programmed AVD following AS or AP.

The AMD can be configured to stimulate one or more sites of the heart chamber simultaneously or sequentially. In conventional Single Site Pacing (SSP), only one site of a particular heart chamber (e.g., LV) is stimulated. Alternatively, multi-site pacing (MSP) may be used as an alternative to SSP. MSP involves electrical stimulation at two or more sites in the intrinsic heart chamber within the cardiac cycle. For example, in LV MSP, multiple LV sites may be stimulated simultaneously, or separated by one or more intra-LV time shifts (ILVD). MSP can improve LV function and hemodynamic response in certain patients. MSPs, however, may require more energy than SSPs and may also increase the complexity of system design and operation. Not all CHF patients can consistently receive more benefit from MSP than SSP.

Stimulation timing parameters (such as AVD, VVD, or ILVD, discussed above) may determine the timing of cardiac stimulation. Since such timing may affect treatment efficacy and patient hemodynamic prognosis, proper selection or programming of stimulation timing parameters may be important in HF management. For example, the AVD may be determined using information about intrinsic AV conduction characteristics of the patient, such AS intrinsic AV intervals (AVIs) between P-waves and R-waves within a cardiac cycle in an Electrocardiogram (ECG), or intrinsic AVIs between atrial events (e.g., Atrial Sensed (AS) or Atrial Paced (AP) events) and ventricular sensed events (VS) within a cardiac cycle in a subcutaneously measured Electrocardiogram (EGM). In a patient, the intrinsic AVI may not remain constant, but rather varies under a variety of physiological or functional conditions. For example, AVI may be affected by long-term changes in the patient's health, HF progression (such as remodeling or decompensation), or short-term changes in heart rate, posture changes, physical activity, sleep/awake state, medications, hydration, diet, and other factors. As such, cardiac stimulation using previously optimized AVDs may not provide the best patient prognosis under different patient conditions.

The present inventors have recognized several technical challenges in cardiac pacing therapy for the treatment of HF. One challenge is associated with personalized and dynamic HF therapy to account for inter-patient variation in cardiac pacing therapy effectiveness, as well as intra-patient variation in cardiac pacing effectiveness over time due to at least long-term or short-term changes in patient condition. Timely adjustment of stimulation parameters such as AVD can improve overall treatment efficacy. Another challenge relates to ensuring adequate ventricular pacing therapy (e.g., CRT), particularly for pacing dependent patients. For example, during therapy optimization to update stimulation parameters, ventricular pacing therapy may need to be temporarily suspended. Some conventional pacing systems may reconfigure a pacing electrode (e.g., an LV pacing electrode) to sense cardiac electrical activity during therapy optimization. For example, when a patient condition changes, frequent assessments of AVI may require that pacing electrodes be reconfigured as sensing electrodes to sense activation of the ventricles. Frequent electrode reconfiguration may increase the complexity of the pacing system, place greater demands on computational resources such as firmware cycles, increase design and operational costs, and shorten battery life. Suspending pacing to reassess AVI may adversely affect the patient's prognosis.

This document provides a technical solution to the above-mentioned challenges in cardiac pacing therapy of HF and may thus improve the medical technology of device-based HF management. This document provides, among other things, apparatus and methods for dynamically updating stimulation parameters, including stimulation timing parameters, such as AVD values. The dynamic parameter updates discussed herein may also be applied to other stimulation parameters, such as for determining stimulation sites or stimulation patterns. Dynamic parameter updates may tailor cardiac pacing therapy to individual patients as well as patient physiological or functional conditions. In some examples, stimulation parameter values (e.g., AVD values) corresponding to a number of patient conditions (e.g., heart rate, atrial paced or atrial sensed events, posture) may be stored in the stimulation parameter table. Adjustments to the stimulation parameters as indicated by the patient condition may result in personalized pacing therapy to meet the patient's needs. The dynamic adjustment may be specific to heart rate or heart rate range, or based on beat-to-beat. In addition to improved treatment efficacy and patient prognosis, the systems and methods discussed herein can also reduce healthcare costs associated with HF management. Further, this document provides for the identification of conditions that may affect stimulation timing and treatment effectiveness. This may facilitate healthcare providers in tracking patient HF progression and improving patient management.

This document also discusses a method for determining a parameter update schedule using patient AV conduction characteristics (e.g., intrinsic AVI), the parameter update schedule indicating the timing at which stimulation parameters are to be updated. At least a portion of the stored set of stimulation parameters may be updated in the determined parameter update schedule. As described above, conventional cardiac pacing therapy may have to be frequently suspended during therapy optimization to sense AV conduction characteristics. This not only affects the prognosis of the patient, but also increases the complexity and cost of the device. The personalized parameter update timing discussed in this document may be dynamically determined based on patient condition (e.g., heart rate, AV conduction characteristics, etc.). This may not only customize stimulation parameters and therapy to the patient's condition in a timely manner, but may also reduce the overall pacing pause time. Thus, patient prognosis and device function may be improved.

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 allow for more efficient device memory usage, such as by storing and updating stimulation timing parameters that are clinically more relevant to long-term and short-term changing conditions of a patient. In addition to therapeutic benefits, the personalized and dynamically adjusted therapy discussed in this document may also conserve device power and extend battery life. With personalized HF therapy tailored to a particular patient condition, fewer unnecessary interventions or hospitalizations may be scheduled, prescribed, or provided; thus, overall cost savings may be realized.

Fig. 1 shows an example of a patient management system 100 and portions of an environment in which the patient management system 100 may operate. Patient management system 100 may include an ambulatory medical device, such as an Implantable Medical Device (IMD)110 that may be electrically coupled to heart 105 by one or more leads 108A-108C, and an external system 120 that may communicate with IMD 110 via communication link 103. Examples of the IMD 110 may include, but are not limited to, pacemakers, defibrillators, CRT devices, cardiac Remodeling Control Therapy (RCT) devices, neuromodulators, drug delivery devices, biological therapy devices, diagnostic devices (such as cardiac monitors or loop recorders), or patient monitors, among others. The IMD 110 may be coupled to or replaced by a monitoring medical device, such as a bedside or other external monitor. Other ambulatory medical devices may be used in addition to or in place of the IMD 110, which may include subcutaneous medical devices such as subcutaneous monitors or diagnostic devices, or external monitoring or therapy medical devices such as Automated External Defibrillators (AEDs) or dynamic electrocardiogram (Holter) monitors; a wearable medical device, such as a patch-based device, a smart watch, or a smart accessory; or a bedside monitor.

The IMD 110 can include a hermetically sealed can 112 that can house electronic circuitry that can sense physiological signals in the heart 105 and can deliver one or more therapeutic electrical pulses to a target area, such as in the heart, such as through one or more leads 108A-108C. The patient management system 100 may include only one lead, such as 108B, or may include two leads, such as 108A-108B.

Lead 108A may include a proximal end that may be connected to IMD 110 and a distal end that may be placed at a target location, such as Right Atrium (RA)131 of heart 105. Lead 108A may have a first pacing sensing electrode 141, which may be located at or near its distal end, and a second pacing sensing electrode 142, which may be located at or near electrode 141. Electrodes 141 and 142 may be electrically connected to IMD 110, such as via separate conductors in lead 108A, such as to allow sensing of right atrial activity and optional delivery of atrial pacing pulses. Lead 108B may be a defibrillation lead that may include a proximal end that may be connected to IMD 110 and a distal end that may be placed at a target location, such as Right Ventricle (RV)132 of heart 105. Lead 108B may have a first pacing sensing electrode 152 at the distal end, a second pacing sensing electrode 153 that may be located near electrode 152, a first defibrillation coil electrode 154 that may be located near electrode 153, and a second defibrillation coil electrode 155 that may be located a distance from the distal end, such as for Superior Vena Cava (SVC) placement. The electrodes 152-155 may be electrically connected to the IMD 110, such as via separate conductors in the lead 108B. Electrodes 152 and 153 may allow sensing of ventricular EGMs and may optionally allow delivery of one or more ventricular pacing pulses, and electrodes 154 and 155 may allow delivery of one or more ventricular cardioversion/defibrillation pulses. In an example, lead 108B may include only three electrodes 152, 154, and 155. Electrodes 152 and 154 may be used to sense or deliver one or more ventricular pacing pulses, and electrodes 154 and 155 may be used to deliver one or more ventricular cardioversion or defibrillation pulses. The lead 108C may include a proximal end that may be connected to the IMD 110 and a distal end that may be placed at a target location, such as in the Left Ventricle (LV)134 of the heart 105. Lead 108C may be implanted through coronary sinus 133 and may be placed in a coronary vein above the LV to allow delivery of one or more pacing pulses to the LV. Lead 108C may include an electrode 161 that may be located at a distal end of lead 108C and another electrode 162 that may be located near electrode 161. Electrodes 161 and 162 may be electrically connected to IMD 110, such as via separate conductors in lead 108C to allow sensing of the LV EGM and optionally to allow delivery of one or more resynchronization pacing pulses from the LV. Additional electrodes may be included in lead 108C or along lead 108C. In an example, as shown in fig. 1, the third electrode 163 and the fourth electrode 164 may be included in the lead 108. In some examples (not shown in fig. 1), at least one of the leads 108A-108C, or additional leads in addition to the leads 108A-108C, may be implanted beneath the skin surface rather than within at least one heart chamber, or at or near heart tissue.

The IMD 110 may include circuitry that may sense physiological signals. The physiological signals may include EGMs or signals indicative of mechanical function of heart 105. Hermetically sealed can 112 can be used as an electrode, such as for sensing or pulse delivery. For example, electrodes from one or more of leads 108A-108C may be used with can housing 112, such as for unipolar sensing of EGMs or for delivery of one or more pacing pulses. Defibrillation electrodes from lead 108B may be used with canister housing 112, such as for delivering one or more cardioversion/defibrillation pulses. In an example, the IMD 110 may sense impedance, such as between electrodes located on the can housing 112 or one or more of the leads 108A-108C. The IMD 110 may be configured to: current is injected between pairs of electrodes, the resultant voltage between the same or different pairs of electrodes is sensed, and the impedance is determined using ohm's law. The impedance may be sensed in a bipolar configuration (where the same pair of electrodes may be used for injecting current and sensing voltage), a tripolar configuration (where the pair of electrodes for current injection and the pair of electrodes for voltage sensing may share a common electrode), or a quadrupolar configuration (where the electrodes for current injection may be different from the electrodes for voltage sensing). In an example, the IMD 110 may be configured to inject a current between an electrode on the RV lead 108B and the can housing 112 and sense a resultant voltage between the same electrodes or between a different electrode on the RV lead 108B and the can housing 112. The physiological signals may be sensed from one or more physiological sensors that may be integrated within the IMD 110. The IMD 110 may also be configured to sense physiological signals from one or more external physiological sensors or one or more external electrodes that may be coupled to the IMD 110. Examples of physiological signals may include one or more of the following: ECG, intracardiac EGM, heart rate variability, intrathoracic impedance, intracardiac impedance, arterial pressure, pulmonary arterial pressure, left atrial pressure, RV pressure, LV coronary arterial pressure, coronary arterial blood temperature, blood oxygen saturation, one or more heart sounds, physical activity or exertion level, physiological response to activity, posture, respiration, body weight or temperature, and others.

In certain examples, the system 100 may include one or more leadless sensors tethered to the IMD 110 not via leads 108A-108C. The leadless flow sensor may be configured to sense physiological signals and wirelessly communicate with the IMD 110. In some examples, the IMD 110 may be a leadless medical device. Unlike tethered devices such as the IMD 110 shown in fig. 1, leadless medical devices do not require leads, or tethers to extend between the electrodes and the device body. The leadless medical device may include an anchoring or fixation mechanism for positioning the device body on a target implant side, such as an endocardial surface of one of the left ventricle, right ventricle, left atrium, or right atrium, or an epicardial surface of a portion of the heart. The leadless medical device may be delivered intravenously and positioned within a vessel on the heart, such as a coronary vein, where one or more electrodes on the leadless medical device may directly or indirectly contact an epicardial surface of the heart. Examples of such leadless medical devices may include the Leadless Cardiac Pacemaker (LCP) disclosed in commonly assigned U.S. patent application publication US2016/0051823 to Maile et al, entitled "LEADLESS CARDIAC PACEMAKER HAVING A SENSOR WITH a POWER device MODE," the entire contents of which are incorporated herein by reference.

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 patient management system 100 may include a dynamically controlled stimulation circuit 113. The dynamically controlled stimulation circuit 113 may dynamically determine the treatment parameters based on the current physiological or functional condition of the patient. Patient conditions (such as patient health, HF progression, remodeling or decompensation, heart rate, posture changes, physical activity, sleep/awake state, medications, hydration, diet, and other factors) may affect the electrical and mechanical properties of the heart and thus the HF treatment effect. The dynamically controlled stimulation circuit 113 may use the sensor input to determine stimulation parameters (e.g., AVD). In an example, the stimulation parameters may be arranged in a table stored in memory along with the respective patient physical and physiological condition. In some examples, the dynamically controlled stimulation circuit 113 may determine a stimulation site (such as between LV-only pacing and BiV pacing) or a stimulation mode (such as between SSP and MSP) based on sensor inputs. The dynamically controlled stimulation circuit 113 may determine a parameter update schedule (such as the timing at which stimulation parameters are to be updated) using patient AV conduction characteristics (such as intrinsic AVI) and update at least a portion of the stored stimulation parameters at the determined parameter update timing. For a specified heart rate (intrinsic or atrial paced) or range of heart rates, dynamically controlled stimulation circuitry 113 may select a stimulation parameter (e.g., AVD value) from a set of stimulation parameters and deliver cardiac pacing according to the selected stimulation parameter. Examples of personalized updating of stimulation parameters and dynamically controlled cardiac pacing are described below, such as with reference to fig. 2.

The external system 120 may allow the IMD 110 to be programmed and receive information from the IMD 110 via the communication link 103. External system 120 may include a local external IMD programmer. The external system 120 may include a remote patient management system that may monitor patient status or adjust one or more treatments, such as from a remote location. The remote patient management system may evaluate the collected patient data and provide alarm notifications, among other possible functions. In an example, the remote patient management system may include a central server that acts as a central hub for the storage and analysis of collected patient data. The servers may be configured as single, multiple, or distributed computing and processing systems. The remote patient management system may additionally or alternatively include one or more locally configured clients or remote clients securely connected to the server. Examples of clients may include personal desktops, laptops, mobile devices, or other computing devices. A system user (such as a clinician or other qualified medical professional) may use a client to securely access stored patient data aggregated in a database of a server.

The communication link 103 may include one or more of an inductive telemetry link, a radio frequency telemetry link, or a telecommunications link, such as an internet connection. The communication link 103 may provide for data transfer between the IMD 110 and the external system 120. The transmitted data may include, for example, real-time physiological data acquired by the IMD 110, physiological data acquired by and stored in the IMD 110, therapy history data or data indicative of an operating state of the IMD, programming instructions to the IMD 110 (to configure the IMD 110 to perform one or more actions including, for example, data acquisition, device self-diagnostic testing, or therapy delivery).

The dynamically controlled stimulation circuit 113 may be implemented at the external system 120 (such as using data extracted from the IMD 110 or data stored in a memory within the external system 120). Portions of the dynamically controlled stimulation circuitry 113 may be distributed between the IMD 110 and the external system 120.

Portions of the IMD 110 or the external system 120 may be implemented using hardware, software, or any combination of hardware and software. The IMD 110 or portions of the external system 120 may be implemented using dedicated circuitry that may be constructed or configured to perform one or more particular functions, or may be implemented using general-purpose circuitry that may be programmed or otherwise configured to perform one or more particular functions. Such general purpose circuitry may include a microprocessor or a portion thereof, a microcontroller or a portion thereof, or programmable logic circuitry or a portion thereof. For example, a "comparator" may include, among other things, an electronic circuit comparator that may be configured to perform a particular function of a comparison between two signals, or may include a comparator that may be implemented as part of a general purpose circuit that may be driven by code instructing a portion of the general purpose circuit to perform a comparison between two signals. Although described with reference to IMD 110, patient management system 100 may include a subcutaneous medical device (e.g., subcutaneous ICD, subcutaneous diagnostic device), wearable medical device (e.g., patch-based sensing device), or other external medical device.

Fig. 2 shows an example of a dynamically controlled cardiac stimulation system 200, which may be configured to generate a personalized schedule for updating stimulation parameters. Examples of such personalized schedules are: the timing of the parameter update may be determined using patient AV conduction characteristics or other patient physiological or functional conditions. The system 200 may update the stimulation parameters at a time or frequency that is timed according to the parameter update and select the stimulation parameters to be used during cardiac stimulation.

The dynamically controlled cardiac stimulation system 200 may include one or more of a sensor circuit 210, a stimulation control circuit 240, a memory circuit 250, and a user interface 260. In some examples, the system 200 may additionally include therapy circuitry 270 configured to deliver or adjust therapy, such as cardiac pacing therapy. At least a portion of cardiac monitoring system 200 may be implemented in an AMD, such as IMD 110, or distributed between the AMD and an external system, such as external system 120.

The sensor circuit 210 may include a sense amplifier for sensing cardiac signals. Cardiac signals may be sensed from different heart chambers, such as one or more of the RA, RV, Left Atrium (LA), or LV. Cardiac signals may be sensed when the heart experiences an intrinsic rhythm, such as a sinus rhythm, or when the heart is stimulated according to a stimulation protocol, such as pacing at an atrium, ventricle, or other site at a specified frequency or timing. Examples of cardiac signals may include cardiac electrical signals, such as an ECG non-invasively sensed from the body surface, a subcutaneous ECG sensed from subcutaneously placed electrodes, or an intracardiac EGM sensed from electrodes on the can housing 112 or one or more of the leads 108A-108C. By way of example and not limitation, atrial activation (represented by AS) may be sensed using a sensing vector that includes one of atrial electrodes 141 or 142, right ventricular activation (RVs) may be sensed using a sensing vector that includes one of RV electrodes 152 and 154, and left ventricular activation (LVs) may be sensed using a sensing vector that includes one of LV electrodes 161 and 164.

Additionally or alternatively, the cardiac signal may comprise a signal indicative of cardiac mechanical activity or patient hemodynamic status. In an example, the cardiac signal may include a signal sensed from an accelerometer or microphone configured to sense heart sounds of 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 the mechanical activity or hemodynamic state of the heart.

In some examples, the sensor circuit 210 may sense two or more cardiac signals from different sites of the heart chamber (such as multiple sites at the LV) simultaneously or sequentially. The sensor circuit 210 may sense LV EGMs from two or more LV sites using respective sensing vectors. Examples of LV sensing vectors may include bipolar sensing vectors, such as between electrode pairs selected among 161-164. Alternatively, the LV sensing vector may be between one of electrodes 161-164 and another electrode positioned on a different chamber or a different lead (e.g., one of 152-155 on RV lead 108B, or electrodes 141 or 142 on RA lead 108A). Another example of an LV sensing vector may include a unipolar sensing vector that includes one of canister housing 112 and electrodes 161 and 164.

The sensor circuit 210 may process the sensed cardiac signal including amplification, digitization, filtering, or other signal conditioning operations. The sensor circuit 210 may include or be coupled to a feature generator 212, the feature generator 212 configured to generate signal features from the processed cardiac signal. Examples of signal features may include time or morphological features indicative of intrinsic cardiac activity, such as P-waves, Q-waves, R-waves, QRS complexes or T-waves that may be detected from surface ECG, subcutaneous ECG or intracardiac EGMs, timing and intensity of induced cardiac activity, such as induced electrical or mechanical activation in response to electrical stimulation of the heart. Examples of timing measurements may include time delays between cardiac activations sensed at different heart chambers (e.g., AVI between atrium and ventricle, or RV-LV interval), or between different pacing sites (e.g., delays between sensing various LV sites).

In an example, the feature generator 212 may use the signals received by the sensor circuit 210 to determine a heart rate. In an example, the heart rate is an intrinsic heart rate without atrial pacing. In another example, heart rate is detected during atrial pacing. The rate of such atrial pacing is substantially equal to the rate of atrial pacing. The heart rate may be used to schedule parameter updates, such as to determine parameter update timing. In an example, the parameter update timing includes a parameter update frequency. The heart rate may also be used to select stimulation parameters from a set of stimulation parameters stored in memory 250. In an example, the feature generator 212 may determineIntrinsic AV conduction characteristics, such as intrinsic AVI, are determined. In an example, intrinsic AVI is measured when ventricular pacing (e.g., CRT) is temporarily suspended. In an example, an atrial to RV interval (AV) may be used_R) And atrial-to-LV interval (AV)_L) To determine the inherent AVI. In some examples, the offset between the AVD and the AVI corresponding to the pseudo-fused beat may be used during pacing to estimate the AVI. The offset may be stored in memory. In varying patient conditions, the AVI may be estimated using a combination of the AVD and the stored offset that results in a spurious fusion. An example OF AVI estimation based on pseudofusion during pacing is disclosed in commonly assigned U.S. patent application No. 16/007,094 entitled "SYSTEMS AND METHOD FOR DYNAMIC CONTROL OF HEART FAILURE THERAPY" to Ternes et al, the entire contents OF which are incorporated herein by reference.

In some examples, the sensor circuit 210 may additionally receive information regarding a long-term or short-term physiological or functional condition of the patient. Changes in long-term or short-term patient conditions may affect the cardiac electrical and mechanical properties as well as the patient's hemodynamic response. Thus, if not timely and appropriately adjusted to accommodate changing patient conditions, the treatment may be less effective. Physiological signals, such as cardiac, pulmonary, neural, or biochemical signals, may be received at the sensor circuit 210. Examples of physiological signals may include ECG, intracardiac EGM, heart rate signal, heart rate variability signal, cardiovascular pressure signal, heart sound signal, respiration signal, thoracic impedance signal, respiration sound signal, or blood chemistry measurements or expression levels of one or more biomarkers. Examples of functional signals may include patient posture, gait, balance or physical activity signals, among others. The sensor circuit may use motion sensors such as accelerometers, gyroscopes (which may be one, two or three axis gyroscopes), magnetometers (e.g., compasses), inclinometers, goniometers, altimeters, Electromagnetic Tracking System (ETS) or Global Positioning System (GPS) sensors, among others, to sense the functional signals. In another example, the functional signal may include information about a sleep state signal, such as a sleep or awake state, a frequency or duration of sleep position transitions, a sleep inclination, or other indicators of sleep quality. In another example, the functional signal may include information regarding food or beverage intake (e.g., swallowing), cough, or inhalation detection. In some examples, information about the patient physiological or functional condition may be stored in a storage device, such as an Electronic Medical Record (EMR) system, and the sensor circuitry 210 may be configured to receive the patient condition from the storage device in response to user input or triggered by a particular event.

In some examples, the sensor circuit 210 can receive information about patient history, drug intake, hospitalization, surgery, cardiac remodeling, heart failure worsening events (such as heart failure decompensation), or HF complications. In some examples, the sensor circuit 210 may receive device implant information, such as the location of an implantable lead. For example, the LV lead 108C may be implanted at the free wall, anterior, lateral, or posterior, among other possible LV locations. LV lead location may affect the effectiveness of treatment and may be used to determine stimulation site, mode, and timing parameters. In some examples, the sensor circuit 210 may additionally include patient echocardiography-derived measurements, such as ejection fraction, cardiac contractility, cardiac timing or aortic velocity, and other hemodynamic parameters or other clinical diagnoses.

Stimulation control circuitry 240 may update one or more stimulation parameters at a particular time or according to a particular update frequency and select stimulation parameters for use during cardiac stimulation. The stimulation parameters may include one or more stimulation timing parameters, such as AVD. The stimulation control circuit 240 may be implemented as part of a microprocessor circuit, which may be a dedicated processor, such as a digital signal processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other type of processor for processing information including physical activity information. Alternatively, the microprocessor circuit may be a general purpose processor that can receive and implement a set of instructions to perform the functions, methods, or techniques described herein.

The stimulation control circuit 240 may include a circuit set that includes other circuits or sub-circuits, such as one or more of a parameter update scheduler circuit 241, a stimulation timing adjuster circuit 242, and a stimulation parameter selector circuit 243. These circuits may perform the functions, methods, or techniques described herein, either individually or in combination. In an example, the hardware of the circuit group may be immutably designed to perform a particular operation (e.g., hardwired). In an example, the hardware of the circuit set may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) that include a computer-readable medium physically modified (e.g., magnetically, electrically, movably placed of invariant aggregate particles, etc.) to encode instructions for a particular operation. When connecting physical components, the underlying electrical properties of the hardware components change, for example, from an insulator to a conductor, or vice versa. The instructions enable embedded hardware (e.g., an execution unit or loading mechanism) to create members of a circuit group in the hardware via a variable connection to perform portions of a particular operation when operating. Thus, when the device is operating, the computer readable medium is communicatively coupled to the other components of the circuit group member. In an example, any of the physical components may be used in more than one member of more than one circuit group. For example, in operation, the execution unit may be used in a first circuit of a first circuit group at one point in time and reused by a second circuit of the first circuit group or reused by a third circuit of the second circuit group at a different time.

The parameter update scheduler circuitry 241 may be configured to determine an individualized parameter update schedule, such as parameter update timing. The parameter update timing may be generated using patient physiological or functional information, such as heart rate or AV conduction characteristics, such as received by the sensor circuit 210. In some examples, the stimulation timing parameters (e.g., AVD values) may correspond to multiple heart rate ranges. The parameter update scheduler circuitry 241 may determine parameter update timings for a plurality of heart rates or heart rate ranges, respectively. The parameter update timing for one heart rate range may be different than the parameter update timing for another heart rate range. For example, for a first heart rate range of 60-70bpm, the AVD may be updated at a first frequency of once every 10 minutes. For a second heart rate range of 80-90bpm, the AVD may be updated at a second frequency once every 5 minutes. Parameter update timings for a plurality of heart rate ranges, each of which may be determined using AV conduction characteristics measured in the corresponding heart rate range. An example of determining personalization parameter update timing is discussed below, such as with reference to fig. 3.

Stimulation timing adjuster circuitry 242 may be configured to use patient physiological or functional information, such as measurements of AV conduction characteristics, to determine or update stimulation timing parameters. The stimulation timing parameters may be determined or updated at a particular time or at a particular periodic update frequency, such as updating the timing according to parameters provided by the parameter update scheduler circuit 241. The stimulation timing parameters define a timing for delivering the cardiac stimulation pulses. Examples of timing parameters may include AVD, VVD, or ILVD. In an example, stimulation timing adjuster circuit 242 may use the patient-inherent AVI to determine or update the AVD. The AVI may be measured at the determined parameter update timing. In an example, stimulation timing adjuster circuit 242 may set a timer whose duration corresponds to a parameter update timing, such as 10 minutes. The timer may reset to the duration value immediately after the AVI evaluation and count down as time passes until the timer duration expires, at which point another AVI measurement may be taken.

Stimulation timing adjuster circuit 242 may determine or update the stimulation timing parameters using a weighted combination of: (1) both the historical stimulation timing parameter values and (2) the determined values of AV conduction characteristics (each scaled by a respective weighting factor). In an example, the AVD may be updated recursively using intrinsic AVI values, as follows:

AVD(n)＝a*AVD(n-1)+b*AVI(n) (1)

where AVD (n) represents a newly updated AVD value, AVD (n-1) represents a historical AVD value before updating, and AVI (n) represents a current intrinsic AVI value determined with time or frequency according to parameter update timing. In an example, stimulation timing adjuster circuit 242 may use information of the patient's physical activity to adjust one or more of the weighting factors "a" or "b". At higher levels of physical activity, the intrinsic AVI may change more. The AVD may be adjusted to account for changes indicated by activity in the AVI. In an example, in response to an elevated level of physical activity, stimulation timing adjuster circuit 242 may decrease the weighting factor "a" to reduce the effect of the historical AVD value and/or increase the weighting factor "b" to increase the sensitivity of the current AVI.

In an example, stimulation timing adjuster circuit 242 may be used in the right ventricle (AV)_R) At the measured AVI and in the left ventricle (AV)_L) To determine or update the AVD from a combination of the measured AVIs. AV (Audio video)_RRepresenting the interval between Atrial Sensed (AS) or Atrial Paced (AP) activation and sensed RV activation (RVs). AV (Audio video)_LRepresenting the interval from AS or AP activation to sensed LV activation (LVs). Commonly assigned U.S. patent application No. 16/007,094 to Ternes et al, entitled "SYSTEMS AND METHODS FOR DYNAMIC CONTROL OF Heat FAILURE thermal" discusses a method OF using AV_RAnd AV_LThe disclosure of which is incorporated herein by reference in its entirety.

The memory circuit 250 may be configured to store a set of stimulation parameters, such as AVDs. The stimulation timing parameters may correspond to each of a plurality of heart rates or heart rate ranges. In some examples, the stimulation timing parameters may further correspond to other patient conditions, such AS Atrial Sensed (AS) events or Atrial Paced (AP) events, different postures, or different times of day. The memory circuit 250 may be coupled to the stimulation timing adjuster circuit 242, which may update at least a portion of the stored set of stimulation parameters with new values of the stimulation parameters, such as an AVD updated according to equation (1). When AVDs are determined and stored in memory for different heart rates or heart rate ranges, AS or AP events, different postures, or other patient conditions, respectively, stimulation timing adjuster circuit 242 may update the AVD for the corresponding patient condition accordingly, such AS by using the AVI measured during the corresponding patient condition according to equation (1) above. In some examples, the memory circuit 250 may store a stimulation parameter table that includes stimulation timing parameter values and corresponding multiple heart rates or heart rate ranges, optionally along with information of one or more other patient conditions (e.g., posture), or time of day, as shown in fig. 4A-4C below.

Stimulation parameter selector circuit 243, coupled to memory circuit 250, may select stimulation parameters from a set of stimulation parameters stored in memory, including dynamically updated stimulation timing parameters provided by stimulation timing adjuster circuit 242, for use during cardiac stimulation. Stimulation parameter selector circuit 243 may search the stored stimulation parameters for a received patient condition (e.g., heart rate, AS or AP event, posture, or time of day) and identify recommended stimulation parameters (e.g., AVD) corresponding to the patient condition.

The stimulation parameter selector circuit 243 may additionally be configured to determine a heart chamber or one or more heart sites on a heart chamber for pacing from the received patient condition. In an example, stimulation parameter selector circuit 243 may select between LV-only pacing and BiV pacing. BiV pacing refers to stimulating both the LV and RV sequentially, either simultaneously or at specified time offsets. In some patients, BiV pacing may provide better cardiac synchrony and cardiac contractility than LV-only pacing configured to stimulate LV only. However, changes in a patient's physiological or functional conditions (e.g., increased heart rate, or a supine to standing posture transition) may change AV conditions, ventricular contractility, or other cardiac attributes. Pacing chamber switching and other therapeutic adjustments may be required to maintain adequate therapeutic results. Stimulation parameter selector circuit 243 may initiate stimulation site assessment in response to changes in patient condition and make determinations between LV-only pacing and BiV pacing based on indicators of increased heart rate and AV conduction abnormalities, such as prolongation of AVI or an increase in irregularity of AVI.

Additionally or alternatively, the stimulation parameter selector circuit 243 may be configured to determine between Single Site Pacing (SSP) and multi-site pacing (MSP) depending on the received patient condition. MSP can be delivered at two or more sites on the interior or epicardial surface of one or more heart chambers or tissue surrounding any chamber. During MSP, the pulse trains may be delivered simultaneously at two or more cardiac sites, or sequentially with an intra-ventricular delay that is less than the sensed or paced time interval value of the cardiac cycle. The stimulation mode selector circuit 243 may initiate stimulation mode evaluation in response to changes in patient conditions and use the inter-ventricular intervals measured from the RV site to various candidate LV sites (such as those corresponding to LV electrodes 161-164) to determine between SSP pacing and MSP pacing at two or more LV sites. The interventricular interval represents the degree of dyssynchrony between the RV and the various LV sites. The stimulation parameter selector circuit 243 may scan the plurality of candidate LV electrodes to identify those LV sites whose corresponding inter-ventricular intervals satisfy a specified condition (such as a threshold indicated by the patient condition), and select SSP or MSP based on the candidate electrode identification. Commonly assigned U.S. patent application No. 16/007,094 to Ternes et al, entitled "SYSTEMS AND METHODS FOR DYNAMIC CONTROL OF HEART FAILURE THERAPY," discloses examples OF stimulation site selection (e.g., between LV-only pacing and BiV pacing) and stimulation mode selection (e.g., between SSP and MSP) as indicated by patient condition, the disclosure OF which is incorporated herein by reference in its entirety.

The user interface 260 may include an input device that enables a system user to program parameters for electrical stimulation or for sensing cardiac signals. Examples of input devices may include a keyboard, on-screen keyboard, mouse, trackball, touchpad, touchscreen, or other pointing or navigation device. The input device may enable the system user to activate automatic programming of the HF therapy, such as automatically determining stimulation sites, stimulation patterns, and stimulation timing parameters under specific patient conditions. The input device may also enable the system user to confirm, reject, or otherwise modify the automatically determined treatment program.

The user interface 260 may include a display for displaying the treatment program, such as automatically determined stimulation sites, stimulation patterns, and stimulation timing parameters. Output unit 230 may include a printing device for producing a hard copy of the information. The information may be presented in a table, chart, trend, graph, or any other type of textual, tabular, or graphical presentation format. Additional information for display may include cardiac signals sensed from the sensor circuit 210, signal features or measurements (e.g., AVIs) derived from the sensed cardiac signals, information received from the sensor circuit 210 of patient physiological or functional conditions, or device status information such as lead impedance and integrity, battery status such as remaining life of the battery or cardiac stimulation thresholds, or complications associated with stimulation at one or more cardiac sites, among others.

The therapy circuit 270 may be configured to generate a therapy according to the parameter values generated and recommended by the stimulation control circuit 240. The therapy may include electrical stimulation delivered to the pacing site via one or more of the leads 108A-108C and the respective attached electrodes. The therapy circuit 270 may be configured to deliver LV-only pacing or BiV pacing. Additionally or alternatively, the therapy circuit 270 may be configured to generate SSP for stimulating one cardiac site, or MSP for stimulating two or more sites of the heart within the same cardiac cycle. In an example, MSP can be delivered within the LV. The LV MSP may have a unipolar pacing configuration in which only one electrode (e.g., the cathode) is the LV electrode and the other electrode (e.g., the anode) is the IMD can housing 112. In another example, a true bipolar configuration may be used, where both the cathode and anode are LV electrodes. In yet another example, an extended bipolar configuration may be used in which one electrode (e.g., the cathode) is the LV electrode and the other electrode (e.g., the anode) is the RA electrode (such as one of electrodes 141 or 142) or the RV electrode (such as one of electrodes 152 and 155). In another example, a tripolar configuration may be used, which may include two LV electrodes that function together as a cathode, or two electrodes such as selected from RA and RV electrodes that function together as an anode. In an example, the one or more LV electrodes may be distributed in one or more LV leads, catheters, or un-tethered (untethered) pacing units.

In some examples, the therapy circuitry 270 may initiate or adjust electrical stimulation or other therapy types at non-cardiac tissue (such as neural tissue) such as cardioversion therapy, defibrillation therapy, or drug therapy including delivery of drugs to tissues or organs. In some examples, the therapy circuitry 270 may modify an existing therapy, such as adjusting a stimulation parameter or a drug dose.

Fig. 3 is a block diagram illustrating an example of a feature generator circuit 320, the feature generator circuit 320 configured to generate one or more features for use by the parameter update scheduler circuit 241 to determine a timing or frequency for updating the stimulation parameters. The feature generator circuit 320 may be an embodiment of the feature generator circuit 212 of the system 200. In an example, variability metrics (such as AVI variability 321) of patient AV conduction characteristics may be generated using values of AV conduction characteristics. Examples of variability metrics may include range, variance, or standard deviation, among other statistical measures. The parameter update scheduler circuitry 241 may decrease the parameter update frequency if the variability metric is below a variability threshold and increase the parameter update frequency if the variability metric is above the variability threshold. In an example, the measure of variability of the AV conduction characteristics may be compared to one or more thresholds to classify the patient as one of a plurality of levels of change, such as a high level of change, a medium level of change, and a low level of change. The parameter update scheduler circuitry 241 may set the parameter update frequency to coincide with the change level such that, for example, a high change level corresponds to a higher parameter update frequency (i.e., more frequent updates). In some examples, a measure of variability of the AV conduction characteristics may be recorded over a period of time (such as a specified number of days). The parameter update scheduler circuitry 241 may use one or more recorded variability metric values to dynamically update the parameter update frequency.

As a non-limiting example, the initial parameter update timing may be programmed to update the AVD at a predetermined update frequency, such as once every 10 minutes. If the intrinsic AVI is highly variable and exceeds the variability threshold, the parameter update scheduler circuit 241 may increase the AVD update frequency to, for example, once every 8 minutes. However, if the variability of the intrinsic AVI measurements is small and below the variability threshold, the AVD update frequency may remain unchanged or decrease to, for example, once every 12 minutes. An increase in AVI variability may indicate the occurrence of a conduction abnormality, arrhythmia, or other adverse cardiac condition. Updating the AVD more frequently and timely can improve cardiac pacing efficacy and patient hemodynamic prognosis. Conversely, a less varying AVI may indicate stable AV conduction and overall stable cardiac conditions. Not updating parameters or updating less frequently does not adversely affect the effectiveness of the pacing therapy and may reduce pacing pause times (e.g., which are used to re-evaluate AVI and update AVD) and device operating mode switching (e.g., between ventricular pacing and sensing), which may be beneficial to patients, especially those requiring uninterrupted pacing therapy.

In another example, a covariance metric may be generated between AV conduction characteristics (e.g., intrinsic AVI) and heart rate. The AV conduction characteristics may be measured over a range of heart rates. The covariance measure represents the sensitivity of the AV conduction properties to heart rate changes. At higher sensitivity, moderate fluctuations in heart rate can bring about substantial changes in AVI. Thus, more frequent AVI re-assessments and AVD updates may ensure timely capture of AVI changes and adjust therapy accordingly to meet the needs of the patient.

An example of a covariance metric is an AVI-HR correlation 322, which may be calculated using AVI values and corresponding heart rates. The parameter update scheduler circuitry 241 may decrease the parameter update frequency if the correlation is below a correlation threshold and increase the parameter update frequency if the correlation is above the correlation threshold. Another example of a covariance metric may include a rate of change of AVI with respect to heart rate change 323. The parameter update scheduler circuitry 241 may decrease the parameter update frequency if the relative rate of change of the AV conduction characteristic is below a rate threshold, and may increase the parameter update frequency if the relative rate of change of the AV conduction characteristic is above the rate threshold. In an example, the rate of change 323 of the AVI may be represented by a slope of a linear regression between the AV conduction characteristic value and the corresponding heart rate. The parameter update scheduler circuit 241 may decrease the parameter update frequency if the slope is below a slope threshold and increase the parameter update frequency if the slope is above the slope threshold.

The feature generator circuit 320 may additionally or alternatively generate one or more features indicative of a change in cardiac rhythm or cardiac function, including, for example, an arrhythmia indicator 324 or a conduction abnormality indicator 325. The experience of arrhythmia (epicode), or the onset of conduction abnormalities (e.g., frequency-dependent bundle branch block), may interfere with the patient's intrinsic AVI. Accordingly, the parameter update scheduler circuitry 241 may increase the parameter update frequency to ensure that the appropriate pacing therapy is delivered to meet the patient's needs. In another example, the feature generator circuit 320 may generate the indicator of physical activity 326. An increase in physical activity may accelerate the heart rate or trigger a frequency-dependent conduction abnormality or some type of arrhythmia (e.g., sinus tachycardia), thereby introducing a change in the patient's intrinsic AVI. Thus, more frequent AVD updates may help ensure that appropriate pacing therapy is delivered in a timely manner.

Fig. 4A-4C are graphs showing values of stimulation parameters indicative of patient condition, which may be stored in memory for dynamic cardiac pacing. The stimulation parameters may be stored in a table, such as table 410, 420, or 430, which includes recommended stimulation timing values and one or more corresponding patient conditions. Each table entry may include a recommended AVD value for the corresponding patient condition. By way of example and not limitation, fig. 4A illustrates a stimulation parameter table 410 that includes stimulation timing values, such AS AVD values, with corresponding heart rate ranges (HRs), and atrial activation patterns that are either Atrial Sensed (AS) events or Atrial Paced (AP) events. The AVD of an AS event is referred to AS the sensed AVD, and the AVD of an AP event is referred to AS the paced AVD. Fig. 4B shows a stimulation parameter table 420, which is a variation of table 410 augmented by patient posture. By way of example, the postures included in table 420 include supine, sitting, or standing postures. Fig. 4C shows a stimulation parameters table 430, which is another variation of table 410, augmented by information of time of day (such as day or night). Alternatively, the time of day may include multiple time periods during the day within a 24 hour period. In various examples, the tables 410, 420, or 430 may be augmented to include other patient conditions, such as activity (walking or running), sleep, diet, hydration, drug intake, heart rate variability, arrhythmic events (e.g., atrial fibrillation, ventricular tachycardia, premature ventricular beats, post-arrhythmia). Various combinations or permutations of patient conditions may be implemented in a stimulation parameter table similar to tables 310 or 330, which are within the scope of this document. These patient conditions (alone or in combination) may affect cardiac tissue properties and patient hemodynamics. As a result, a therapy programmed in one instance may not be as effective in a different instance. Different AVD values may be recommended under different patient conditions to achieve a desired therapeutic effect and patient prognosis.

In various examples, at least some entries of the stimulation parameter table may additionally or alternatively include recommended values for stimulation timing parameters other than AVDs. In an example, the table entry may include a recommended RV-LV delay (VVD) for respective patient conditions of heart rate, posture, and atrial activation pattern. VVD represents the offset between the LV pacing pulse and RV pacing pulse within a cardiac cycle for BiV pacing or CRT therapy, such as selected by a system user or determined by stimulation parameter selector circuit 243. In some examples, VVD may be set to zero such that LV pacing and RV pacing are delivered simultaneously. In another example, at least some table entries may include a recommended intra-LV time offset (ILVD). ILVD represents the offset between LV pacing pulses delivered at different LV sites within a cardiac cycle, respectively, when the LV MSP is selected by a system user or determined by stimulation parameter selector circuit 243. LV MSP may be delivered via two or more of the LV electrodes 161-164 as shown in fig. 1.

In various examples, the stimulation parameter table may be augmented to include information in addition to stimulation timing parameters. In an example, at least some of the entries of table 410-430 may additionally or alternatively include information about the stimulation site, such as an indication of LV-only pacing or BiV pacing, or information about the stimulation mode, such as an indication of SSP or MSP. Thus, the augmented table provides comprehensive treatment recommendations regarding stimulation site, pattern, and timing values under various patient conditions. In an example, the entries of the expansion table may be structured as class structures in the memory circuit 250 that contain values for one or more of stimulation site, mode, and timing parameters. For example, one table entry may include (AVD, LV-only pace) and another table entry may include (AVD, BiV pace, VVD, MSP, ILVD). In an example, one element of a table entry (e.g., AVD value, BiV pacing, or MSP) may apply to multiple table entries sharing a common condition. For example, if BiV pacing is recommended for conditions defined by sitting posture, AS and HR greater than 100bpm, BiV pacing may be recommended for all conditions regardless of heart rate range, or atrial activation mode (AS or AP), AS long AS the "sitting" posture is included. In another example, if MSP is recommended for conditions defined by standing posture, AS and HR within 70-80bpm, MSP may be recommended for all conditions regardless of heart rate range, or atrial activation pattern, AS long AS "standing" posture is included.

In some examples, multiple tables of stimulation timing parameter values may be constructed and stored in the memory circuit 250, such as an AVD table containing only AVD values for various patient conditions, a VVD table containing only VVD values for various patient conditions, or an ILVD table containing only ILVD values for various patient conditions. The table may include different patient physiological or functional conditions. In an example, stimulation parameter selector circuit 243 may reference a VVD table to determine an optimal VVD value at a particular patient condition when BIV pacing is selected. In another example, the stimulation parameter selector circuit 243 may reference the ILVD table to determine an optimal ILVD value under certain patient conditions when selecting the MSP mode. In another example, stimulation parameter selector circuit 243 may reference an AVD table to determine the best AVD for a particular patient condition, regardless of pacing site or pacing mode.

Fig. 5 is a flow diagram illustrating a method 500 for updating stimulation parameters and delivering cardiac stimulation in accordance with the updated stimulation parameters. Stimulation parameters (such as stimulation timing parameters) may be updated at the personalization parameter update timing. Personalized parameter update timing may customize stimulation parameters to the patient's needs and may reduce the overall pacing pause time due to stimulation parameter updates. The method 500 may be implemented in and performed by an implanted device, such as the IMD 110 or the dynamically controlled cardiac stimulation system 200.

Method 500 begins at 510, where a cardiac signal, such as received by sensor circuit 210, may be used to assess an Atrioventricular (AV) conduction characteristic of a patient. Examples of cardiac signals may include cardiac electrical signals, such as sensed from one or more leads 108A-C or electrodes on can housing 112, such as surface ECG, subcutaneous ECG, or heartAn internal EGM. The cardiac signal may additionally or alternatively comprise a signal indicative of cardiac mechanical activity or patient hemodynamic status. Examples of AV conduction characteristics may include intrinsic atrioventricular interval (AVI) between atrial activation (e.g., an Atrial Sensed (AS) event or an Atrial Paced (AP) event) and a ventricular sensed event. When ventricular pacing is temporarily halted, intrinsic AVI may be measured. In some examples, an AVI (atrial to RV interval, AVI) measured at the RV may be used_R) And AVI measured at the LV (atrial to RV spacing, AVI)_R) To determine the inherent AVI. In some examples, instead of suspending ventricular pacing to directly measure AVI, an offset between the AVD and AVI corresponding to a spurious fused beat may be used to estimate AVI during pacing, such as through a testing procedure. The offset may be stored for future use.

At 520, a personalized parameter update schedule, such as parameter update timing, may be determined using the measured or otherwise estimated AV conduction characteristics (e.g., AVI) from step 510. In an example, the parameter update timing includes a parameter update frequency. In an example, a variability metric of the value of the AV conduction characteristic may be used to determine or update the parameter update timing. The parameter update frequency may be decreased if the variability metric is below a variability threshold, and the parameter update frequency may be increased if the variability metric is above the variability threshold. In an example, the measure of variability of the AV conduction characteristics may be compared to one or more thresholds to classify the patient as one of a plurality of levels of change, such as a high level of change, a medium level of change, and a low level of change. The parameter update frequency may be set to coincide with the change level such that, for example, a high change level corresponds to a higher parameter update frequency (i.e., more frequent updates). In another example, the parameter update timing may be determined or updated using a measure of covariance between: (1) values of AV conduction characteristics corresponding to a plurality of heart rates and (2) a plurality of heart rates. The heart rate may be an intrinsic heart rate without atrial pacing. Alternatively, the heart rate may be acquired during atrial pacing, which is substantially equivalent to the atrial pacing rate. The covariance measure represents the sensitivity of the AV conduction properties (e.g., intrinsic AVI) to heart rate changes. Covariances may include correlations between AVI values and corresponding heart rates. The parameter update frequency may be decreased if the correlation is below a correlation threshold and increased if the correlation is above the correlation threshold. Alternatively, the measure of covariance may be represented by the rate of change of AVI with respect to heart rate changes. The parameter update frequency may be decreased if the relative rate of change of the AV conduction characteristics is below a rate threshold, and the parameter update frequency may be increased if the relative rate of change of the AV conduction characteristics is above the rate threshold. In some examples, information about changes in heart rhythm or heart function may be used to determine or update parameter update timing, such as indications of cardiac arrhythmias or cardiac conduction abnormalities. Information about physical activity may additionally or alternatively be used to determine or adjust parameter update timing. For example, an increase in physical activity may accelerate heart rate, or trigger a frequency-dependent conduction anomaly, thereby introducing a change in the patient's intrinsic AVI. Accordingly, the parameter update frequency may be increased so that more frequent AVD updates may help ensure that appropriate pacing therapy is delivered in a timely manner.

In some examples, a plurality of parameter update timings may be determined for a plurality of heart rates or heart rate ranges, respectively. The parameter update timing for one heart rate or heart rate range may be different than the parameter update timing for another heart rate range. For example, for a heart rate range of 60-70bpm, the stimulation parameters (e.g., AVD) may be updated at a first frequency of once every 10 minutes; however, for a heart rate range of 80-90bpm, the AVD may be updated at a second frequency of once every 5 minutes. The parameter update timings corresponding to the various heart rate ranges may each be determined using signal characteristics (e.g., heart rate, AV conduction characteristics such as AVI) at the corresponding heart rate range.

At 530, at least a portion of the set of stimulation parameters stored in memory may be updated at a particular time or a particular periodic update frequency, such as the parameter update timing determined at step 520. The stimulation timing parameters may be updated using patient physiological or functional information, such as a measure of AV conduction characteristics. The stimulation timing parameters define deliveryTiming of cardiac stimulation and may be important to ensure therapeutic efficacy and patient hemodynamic response. The timing parameters may include AVD, VVD, or ILVD. In an example, the AVD may be updated using the patient-specific AVI measured at the time and frequency according to the parameter update timing determined at 520. In an example, the AVD may be updated recursively using a weighted combination of: (1) the historical stimulation timing parameter values and (2) the determined values of the AV conduction characteristics, such as according to equation (1) above. In another example, the right ventricle (AV) may be used_R) At the measured AVI and in the left ventricle (AV)_L) The AVD is updated from the combination of the measured AVIs.

The dynamically updated portion of the set of stimulation parameters may be stored in a memory. The stimulation timing parameters may correspond to each of a plurality of heart rates or heart rate ranges. In some examples, the stimulation timing parameters may further correspond to other patient conditions, such AS Atrial Sensed (AS) events or Atrial Paced (AP) events, different postures, or different times of day. In some examples, a stimulation parameter table may be created and stored in memory. The table may include stimulation timing parameter values and corresponding heart rates or heart rate ranges, optionally with one or more other patient conditions (e.g., posture), or time of day information, as shown in fig. 4A-4C.

At 540, stimulation parameters may be selected from the set of stimulation parameters stored in memory, including dynamically updated stimulation timing parameters, for use during cardiac stimulation. For a received patient condition (e.g., heart rate, AS or AP event, posture, or time of day sensed from the patient), recommended stimulation parameters (e.g., AVD) corresponding to the patient condition may be identified. Cardiac stimulation (e.g., CRT) may be delivered using selected stimulation parameters. In various examples, a heart chamber (e.g., LV-only pacing, or BiV pacing of the left and right ventricles), or a pacing mode for pacing a heart chamber (e.g., Single Site Pacing (SSP) or multi-site pacing (MSP) of the left ventricle) may be determined based on patient conditions, as discussed above with reference to fig. 2.

Fig. 6 illustrates a block diagram of an example machine 600 on which any one or more of the techniques (e.g., methods) discussed herein may be executed. Portions of this description may apply to the computing framework of various portions of an LCP device, IMD, or external programmer.

In alternative embodiments, the machine 600 may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the machine 600 may operate in the capacity of a server machine, a client machine, or both, in server-client network environments. In an example, the machine 600 may act as a peer machine in a peer-to-peer (P2P) (or other distributed) network environment. The machine 600 may be a Personal Computer (PC), a tablet PC, a set-top box (STB), a Personal Digital Assistant (PDA), a mobile telephone, a web appliance, a network router, switch or bridge, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while only a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations.

As described herein, examples may include or be operated by logic or multiple components or mechanisms. A circuit group is a collection of circuits implemented in tangible entities that include hardware (e.g., simple circuits, gates, logic, etc.). The circuit group members may be flexible over time and underlying hardware variability. The circuit group includes members that can perform specified operations upon operations, either individually or in combination. In an example, the hardware of the circuit group may be designed unchanged to perform a particular operation (e.g., hardwired). In an example, the hardware of the circuit set may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) that include a computer-readable medium physically modified (e.g., magnetically, electrically, movably placed of invariant aggregate particles, etc.) to encode instructions for a particular operation. When connecting physical components, the underlying electrical properties of the hardware composition change, for example, from an insulator to a conductor, or vice versa. The instructions enable embedded hardware (e.g., execution units or loading mechanisms) to create members of a circuit group in the hardware via a variable connection to perform portions of a particular operation when operating. Thus, when the device is operating, the computer readable medium is communicatively coupled to other components of the circuit group member. In an example, any of the physical components may be used in more than one member of more than one circuit group. For example, in operation, the execution unit may be used in a first circuit of a first circuit group at one point in time and reused by a second circuit of the first circuit group, or reused by a third circuit of the second circuit group at a different time.

The machine (e.g., computer system) 600 may include a hardware processor 602 (e.g., a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a hardware processor core, or any combination thereof), a main memory 604 and a static memory 606, some or all of which may communicate with each other via an interconnection link (e.g., bus) 608. The machine 600 may also include a display unit 610 (e.g., a raster display, a vector display, a holographic display, etc.), an alphanumeric input device 612 (e.g., a keyboard), and a User Interface (UI) navigation device 614 (e.g., a mouse). In an example, the display unit 610, the input device 612, and the UI navigation device 614 may be a touch screen display. The machine 600 may additionally include a storage device (e.g., drive unit) 616; a signal generating device 618 (e.g., a speaker); a network interface device 620; and one or more sensors 621, such as a Global Positioning System (GPS) sensor, compass, accelerometer, or other sensor. The machine 600 may include an output controller 628 such as a serial (e.g., Universal Serial Bus (USB)), parallel, or other wired or wireless (e.g., Infrared (IR), Near Field Communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.).

The storage device 616 may include a machine-readable medium 622 on which is stored one or more sets of data structures or instructions 624 (e.g., software) embodying or used by any one or more of the techniques or functions described herein. The instructions 624 may also reside, completely or at least partially, within the main memory 604, within static memory 606, or within the hardware processor 602 during execution thereof by the machine 600. In an example, one or any combination of the hardware processor 602, the main memory 604, the static memory 606, or the storage device 616 may constitute machine-readable media.

While the machine-readable medium 622 is shown to be a single medium, the term "machine-readable medium" can include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 624.

The term "machine-readable medium" may include any medium that is capable of storing, encoding or carrying instructions for execution by the machine 600 and that cause the machine 600 to perform any one or more of the techniques of this disclosure or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting examples of machine-readable media may include solid-state memory and optical and magnetic media. In an example, a mass machine-readable medium includes a machine-readable medium having a plurality of particles with an invariant (e.g., static) mass. Thus, the mass machine-readable medium is a non-transitory propagating signal. Specific examples of the mass machine-readable medium may include: non-volatile memories such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

The instructions 624 may also be transmitted or received over a communication network 626 via the network interface device 620 using any one of a number of transmission protocols (e.g., frame relay, Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), hypertext transfer protocol (HTTP), etc.) using a transmission medium. Example communication networks can include a Local Area Network (LAN), a Wide Area 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., referred to as a "POTS") networkOf the Institute of Electrical and Electronics Engineers (IEEE)802.11 family of standards, referred to asIEEE 802.16 family of standards), IEEE 802.15.4 family of standards, peer-to-peer (P2P) networks, and the like. In an example, the network interface device 620 may include one or more physical jacks (e.g., ethernet, coaxial, or telephone jacks) or one or more antennas to connect to the communication network 626. In an example, the network interface device 620 may include multiple antennas to wirelessly communicate using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques. The term "transmission medium" shall be taken to include any intangible medium that is capable of storing, encoding or carrying instructions for execution by the machine 600, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software.

Various embodiments are shown in the above figures. One or more features from one or more of these embodiments may be combined to form further embodiments.

The method examples described herein may be machine or computer-implemented, at least in part. Some examples may include a computer-readable or machine-readable medium encoded with instructions operable to configure an electronic device or system to perform a method as described in the above examples. Embodiments of such methods may include code, such as microcode, assembly language code, or a high-level language code, to name a few. Such code may include computer readable instructions for performing various methods. The code may form part of a computer program product. Further, the code can be tangibly stored on one or more volatile or non-volatile computer-readable media during execution or at other times.

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.