WEARABLE DEVICE WITH BRIDGE PORTION
The present disclosure relates to a wearable device with a bridge portion and systems/methods relating to the device. Preferred embodiments may include two flexible wings and a bridge connecting the two wings. In some embodiments, the upper surface of the bridge can be non-adhesive and uncoupled to the flexible wing such that the flexible wing can be decoupled from the bridge when the adhesive is adhered to the surface of a user. The bridge can be narrower in some portions, and extend around the housing of the monitor. The bridge can extend beneath the housing and bisect the two flexible wings.
This application is a continuation of U.S. Pat. App. No. 17/396130, filed on Aug. 6, 2021, which claims priority from provisional U.S. Pat. App. No. 63/062,293, filed on Aug. 6, 2020, which is hereby incorporated by reference in its entirety.
BACKGROUNDFor purposes of this disclosure, certain aspects, advantages, and novel features of various embodiments are described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, various embodiments may be or carried out in a manner that achieves one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.
Field of the InventionDisclosed herein are materials, devices, methods, and systems for monitoring physiological signals. For example, such physiological signals may include heart signals, such as an electrocardiogram signal.
Description of the Related ArtAbnormal heart rhythms, or arrhythmias, may cause various types of symptoms, such as loss of-consciousness, palpitations, dizziness, or even death. An arrhythmia that causes such symptoms is often an indicator of significant underlying heart disease. It is important to identify when such symptoms are due to an abnormal heart rhythm, since treatment with various procedures, such as pacemaker implantation or percutaneous catheter ablation, can successfully ameliorate these problems and prevent significant symptoms and death. For example, monitors such as Holter monitors and similar devices are currently in use to monitor heart rhythms.
BRIEF SUMMARY OF EMBODIMENTSEmbodiments described herein are directed to a physiological monitoring device that may be worn continuously and comfortably by a human or animal subject for at least one week or more and more typically two to three weeks or more. In one embodiment, the device is specifically designed to sense and record cardiac rhythm (for example, electrocardiogram, ECG) data, although in various alternative embodiments one or more additional physiological parameters may be sensed and recorded. Such physiological monitoring devices may include a number of features to facilitate and/or enhance the patient experience and to make diagnosis of cardiac arrhythmias more accurate and timely.
In some embodiments, an electronic device for monitoring physiological signals in a mammal comprises: at least two flexible wings extending laterally from a housing, wherein the flexible wings comprise a first set of materials which enable the wings to conform to a surface of the mammal and the housing comprises a second set of materials; a printed circuit board assembly housed within the housing, wherein the housing is configured to prevent deformation of the printed circuit board in response to movement of the mammal; at least two electrodes embedded within the flexible wings, the electrodes configured to provide conformal contact with the surface of the mammal and to detect the physiological signals of the mammal; at least two electrode traces embedded within the wings and mechanically decoupled from the housing, the electrode traces configured to provide conformal contact with the surface of the mammal and transmit electrical signals from the electrodes to the printed circuit board assembly; and, at least one hinge portion connecting the wings to the housing, the hinge portions configured to flex freely at the area where it is joined to the housing.
In certain embodiments, each wing may comprise an adhesive. In embodiments, the electrodes can be in the same plane as the adhesive. In certain embodiments, each wing comprises at least one rim, wherein the rim is thinner than an adjacent portion of each wing. The housing may further comprise dimples or grooves configured to allow for airflow between the housing and the surface of the mammal. In certain embodiments, the rim is configured to prevent the release of a portion of the wing from the surface of the mammal. In some embodiments, an electronic device for monitoring physiological systems may comprise a measuring instrument configured to detect motion signals in at least one axis. This measuring instrument may be an accelerometer that can be configured to detect motion signals in three axes.
In embodiments, the motion signals can be collected in time with the physiological signals. In certain embodiments, a motion artifact is identified when the physiological signals and the motion signals match. Further embodiments may call for an event trigger coupled to the printed circuit board assembly. In some embodiments, the event trigger input is supported by the housing so as to prevent mechanical stress on the printed circuit board when the trigger is activated which, in turn, can reduce a source of artifact in the recorded signal. The event trigger may be concave or convex and larger than a human finger such that the event trigger is easily located. In certain embodiments, the electrode traces are configured to minimize signal distortion during movement of the mammal. In particular embodiments, gaskets may be used as a means for sealable attachment to the housing.
In certain embodiments, a method for monitoring physiological signals in a mammal may comprise: attaching an electronic device to the mammal, wherein the device comprises: at least two electrodes configured to detect physiological signals from the mammal, at least one measuring instrument configured to detect secondary signals, and at least two electrode traces connected to the electrodes and a housing; and, comparing the physiological signals to the secondary signals to identify an artifact.
In certain embodiments, identification of artifacts comprises a comparison between the frequency spectrum of the physiological signals and the frequency spectrum of the secondary signals. In embodiments, the secondary signals comprise motion signals that may be used to derive the activity and position of the mammal. In certain embodiments, the secondary signals are collected in three axes. In some embodiments, a tertiary signal may also be collected. In certain embodiments, the secondary signals comprise information about the connection between the electronic device and the mammal. In some embodiments, the secondary signals may be used to detect when the mammal is sleeping.
In some embodiments, a method of removing and replacing portions of a modular physiological monitoring device may comprise: applying the device described above to a mammal for a period of time greater than 7 days and collecting physiological data; using the device to detect a first set of physiological signals; removing the device from the surface of the mammal; removing a first component from the device; and, incorporating the first component into a second physiological monitoring device, the second physiological monitoring device configured to detect a second set of physiological signals.
In some embodiments, the first component is electrically connected to other device components without the use of a permanent connection. In some embodiments, the device may further comprise spring connections. In certain embodiments, the first component may be preserved for a second use by a housing to prevent damage. In particular embodiments, the first component is secured within a device by a mechanism that is capable of re-securing a second component once the first component is removed.
Certain embodiments may concern a system for inferring cardiac rhythm information from time-series data of heart beat intervals, as obtained from either consumer wearable or medical device products. A further aspect concerns improvements to the system to enable cardiac rhythm information to be inferred in a more robust and/or timely manner through the use of additional sources of data. This additional data may include summary statistics or specific signal features derived from an ECG, user activity time series data derived from an accelerometer, information related to user state, or information related to the day/time of the recording.
In certain embodiments, a system for selective transmission of electrocardiographic signal data from a wearable medical sensor, where QRS refers to the three fiducial points of an ECG recording at the time of ventricle depolarization, may comprise:
- a. A wearable medical sensor incorporating a QRS detector that produces a real-time estimate of each R peak location in the ECG
- b. Transmission of an R-R interval time series together with an onset time stamp from the sensor to a smartphone or internet-connected gateway device, according to a predefined schedule
- c. Transmission of the R-R interval time series and the onset time stamp from the smartphone or internet-connected gateway device to a server
- d. Server-side algorithmic inference of the most probable rhythms and their onset/offset times from the R-R interval time series data
- e. Filtering the list of inferred heart rhythms according to specific filter criteria, such that only inferred rhythms matching the given criteria are retained after filtering
- f. Transmission of the onset/offset time for each rhythm remaining after filtering, from the server to the smartphone or internet-connected gateway device
- g. Transmission of the onset/offset time for each rhythm remaining after filtering, from the smartphone or internet-connected gateway device to the wearable sensor
- h. Transmission of the section of recorded ECG corresponding to each onset-offset time pair from the sensor to the smartphone or internet-connected gateway device
- i. Transmission of the section of recorded ECG corresponding to each onset-offset time pair from the smartphone or internet-connected gateway device to the server
The rhythm filter criteria may be specified by a physician or other medical professional prior to the use of the wearable sensor by a patient. In other embodiments, the rhythm filter criteria are dynamic and can be updated during the use of the system according to predefined rules. In some embodiments, these predefined rules may describe an adjustment to the filter criteria based on previous findings during use of the system. In some embodiments, the onset and offset time for each inferred rhythm may be adjusted such that the resulting duration for each rhythm is less than a given maximum permissible duration. Computed confidence measures may be an input to the rhythm filter criteria. In some embodiments, the system comprises inferring cardiac rhythm information from R-R interval time series data. In certain embodiments, the cardiac rhythm inference system is implemented as a cloud service accessible via an API.
In certain embodiments, the cardiac rhythm inference system is provided through a software library that can be incorporated into a standalone application. The R-R interval values may be are estimated from a photoplethysmography signal.
In certain embodiments of a method for inferring cardiac rhythm information, the cardiac rhythm inference system computes a confidence score for each type of cardiac rhythm, the method comprising:
- a. Computing the frequency and duration of each cardiac rhythm type inferred from the collection of R-R interval time series data for the given user
- b. Estimating a confidence statistic for each rhythm type based on the inferred frequency and duration of the rhythm across the collection of R-R interval time series for the given user
- c. Evaluating if the confidence statistic for each inferred rhythm exceeds a pre-determined threshold value
- d. Providing rhythm information back to the calling software only for those inferred rhythms for which the confidence statistic exceeds the threshold value
In certain embodiments, the cardiac rhythm inference system accepts additional sources of data, comprising one or more of:
- e. User activity time series data measured by an accelerometer
- f. Information on the specific day and time of each R-R interval time series recording
- g. Information on user age, gender, clinical indication for monitoring, pre-existing medical conditions, medication information, and medical history
- h. ECG signal features and summary statistics, such as the mean, median, standard deviation or sum of the ECG signal sample values within a given time period
- i. A confidence rating provided by the measurement device to indicate the quality of heart beat estimation, for example, for each beat or for sequential time periods.
- j. Intra-beat interval measurements
In embodiments, a system for monitoring cardiac signal data, comprises:
- wearable medical sensor, the wearable medical sensor configured to detect cardiac signals from a mammal and estimate the R-peak location within the cardiac signal;
- wherein the wearable medical sensor is configured to transmit an R-R interval time series and a time stamp to an intermediary device, the intermediary device configured to further transmit the R-R interval time series and time stamp to a server;
- wherein the server is configured to infer the most probable rhythms and their onset/offset times from the R-R interval time series and time stamp, the server configured to filter the most probable rhythms according to a first criteria into a filtered data set;
- wherein the server is configured to transmit the filtered data set back to the wearable sensor via the intermediary device; and
- wherein the sensor transmits the full resolution cardiac signal to the server for a time period surrounding each of the filtered events.
In certain embodiments, a system for monitoring cardiac signal data comprises:
- a server configured to communicate with a wearable sensor, the wearable sensor configured to detect cardiac signals from a mammal and estimate the R peak location within the cardiac signal;
- wherein the wearable sensor is configured to transmit an R-R interval time series and a time stamp to the server;
- wherein the server is configured to infer the most probable rhythms and their onset/offset times from the R-R interval time series and time stamp, the server configured to filter the most probable rhythms according to a first criteria into a filtered data set; and
- wherein the server is configured to transmit a summary of the filtered data.
In particular embodiments, a server for monitoring cardiac signal data, comprises:
- a portal configured to communicate with a wearable sensor, the wearable sensor configured to detect cardiac signals from a mammal and estimate the R peak location within the cardiac signal, wherein the wearable sensor is configured to transmit an R-R interval time series and a time stamp to an intermediary device, the intermediary device configured to further transmit the R-R interval time series and time stamp to a server;
- a processor configured to infer the most probable rhythms and their onset/offset times from the R-R interval time series and time stamp, the processor configured to filter the most probable rhythms according to a first criteria into a filtered data set; and
- wherein the server is configured to transmit a summary of the filtered data set.
In embodiments, a non-transitory storage medium having computer-executable instructions stored thereon, the computer-executable instructions readable by a computing system comprising one or more computing devices, wherein the computer-executable instructions are executable on the computing system in order to cause the computing system to perform operations comprises: receiving, by a computing system through a communication link, physiological sensor data generated by a patient monitoring device, the physiological sensor data associated with a first patient; analyzing, by the computing system, the physiological sensor data to determine whether one or more points in the physiological data that are likely indicative of one or more predetermined set of conditions; and after determining that at least one of the one or more points in the physiological data is likely indicative of at least one of the one or more predetermined set of conditions, generating, by the computing system, an electronic data package for transmission to the patient monitoring device, the electronic data package including location data regarding the at least one of the one or more points in the physiological sensor data that are likely indicative of the at least one of the one or more predetermined set of conditions.
In certain embodiments, the physiological sensor data may comprise a sampling of interval data measured from the recorded signal data, the sampling of interval data of a data size less than the recorded signal data.
In particular embodiments, a system for monitoring physiological signals in a mammal may comprise: a wearable adhesive monitor configured to detect and record cardiac rhythm data from a mammal, the wearable adhesive monitor configured to extract a feature from the cardiac rhythm data; and wherein the wearable adhesive monitor is configured to transmit the feature to a processing device, the processing device configured to analyze the feature, identify locations of interest, and transmit the locations of interest back to the wearable adhesive monitor.
In certain embodiments, a system for assessing physiological sensor data from a patient monitoring device comprises: a computer processor and non-transitory computer-readable media combined with the computer processor configured to provide a program that includes a set of instructions stored on a first server, the set of instructions being executable by the computer processor, and further configured to execute a sensor data inference module of the program; the sensor data inference module of the program storing instructions to: receive physiological sensor data generated by a patient monitoring device, the physiological sensor data associated with a first patient; analyze the physiological sensor data to determine whether one or more points in the physiological data that are likely indicative of one or more predetermined set of conditions; and after determining that at least one of the one or more points in the physiological data is likely indicative of at least one of the one or more predetermined set of conditions, generating an electronic data package for transmission to the patient monitoring device, the electronic data package including location data regarding the at least one of the one or more points in the physiological sensor data that are likely indicative of the at least one of the one or more predetermined set of conditions.
In certain embodiments, a computerized method may comprise: accessing computer-executable instructions from at least one computer-readable storage medium; and executing the computer-executable instructions, thereby causing computer hardware comprising at least one computer processor to perform operations comprising: receiving, by a server computer through a communication link, physiological sensor data generated by a patient monitoring device, the physiological sensor data associated with a first patient; analyzing, by the server computer, the physiological sensor data to determine whether one or more points in the physiological data that are likely indicative of one or more predetermined set of conditions; and after determining that at least one of the one or more points in the physiological data is likely indicative of at least one of the one or more predetermined set of conditions, generating, by the server computer, an electronic data package for transmission to the patient monitoring device, the electronic data package including location data regarding the at least one of the one or more points in the physiological sensor data that are likely indicative of the at least one of the one or more predetermined set of conditions.
These and other aspects and embodiments of the invention are described in greater detail below, with reference to the drawing figures.
The following description is directed to a number of various embodiments. The described embodiments, however, may be implemented and/or varied in many different ways. For example, the described embodiments may be implemented in any suitable device, apparatus, or system to monitor any of a number of physiological parameters. For example, the following discussion focuses primarily on long-term, patch-based cardiac rhythm monitoring devices. In one alternative embodiment, a physiological monitoring device may be used, for example, for pulse oximetry and diagnosis of obstructive sleep apnea. The method of using a physiological monitoring device may also vary. In some cases, a device may be worn for one week or less, while in other cases, a device may be worn for at least seven days and/or for more than seven days, for example between fourteen days and twenty-one days or even longer. Many other alternative embodiments and applications of the described technology are possible. Thus, the following description is provided for exemplary purposes only. Throughout the specification, reference may be made to the term “conformal.” It will be understood by one of skill in the art that the term “conformal” as used herein refers to a relationship between surfaces or structures where a first surface or structure adapts to the contours of a second surface or structure.
Since abnormal heart rhythms or arrhythmias can often be due to other, less serious causes, a key challenge is to determine when any of these symptoms are due to an arrhythmia. Oftentimes, arrhythmias occur infrequently and/or episodically, making rapid and reliable diagnosis difficult. As mentioned above, currently, cardiac rhythm monitoring is primarily accomplished through the use of devices, such as Holter monitors, that use short-duration (less than 1 day) electrodes affixed to the chest. Wires connect the electrodes to a recording device, usually worn on a belt. The electrodes need daily changing and the wires are cumbersome. The devices also have limited memory and recording time. Wearing the device interferes with patient movement and often precludes performing certain activities while being monitored, such as bathing. Further, Holter monitors are capital equipment with limited availability, a situation that often leads to supply constraints and corresponding testing delays. These limitations severely hinder the diagnostic usefulness of the device, the compliance of patients using the device, and the likelihood of capturing all important information. Lack of compliance and the shortcomings of the devices often lead to the need for additional devices, follow-on monitoring, or other tests to make a correct diagnosis.
Current methods to correlate symptoms with the occurrence of arrhythmias, including the use of cardiac rhythm monitoring devices, such as Holter monitors and cardiac event recorders, are often not sufficient to allow an accurate diagnosis to be made. In fact, Holter monitors have been shown to not lead to a diagnosis up to 90% of the time (“Assessment of the Diagnostic Value of 24-Hour Ambulatory Electrocardiographic Monitoring”, by DE Ward et al. Biotelemetry Patient Monitoring, vol. 7, published in 1980).
Additionally, the medical treatment process to actually obtain a cardiac rhythm monitoring device and initiate monitoring is typically very complicated. There are usually numerous steps involved in ordering, tracking, monitoring, retrieving, and analyzing the data from such a monitoring device. In most cases, cardiac monitoring devices used today are ordered by a cardiologist or a cardiac electrophysiologist (EP), rather than the patient’s primary care physician (PCP). This is of significance since the PCP is often the first physician to see the patient and determine that the patient’s symptoms could be due to an arrhythmia. After the patient sees the PCP, the PCP will make an appointment for the patient to see a cardiologist or an EP. This appointment is usually several weeks from the initial visit with the PCP, which in itself leads to a delay in making a potential diagnosis as well as increases the likelihood that an arrhythmia episode will occur and go undiagnosed. When the patient finally sees the cardiologist or EP, a cardiac rhythm monitoring device will usually be ordered. The monitoring period can last 24 to 48 hours (Holter monitor) or up to a month (cardiac event monitor or mobile telemetry device). Once the monitoring has been completed, the patient typically must return the device to the clinic, which itself can be an inconvenience. After the data has been processed by the monitoring company or by a technician on-site at a hospital or office, a report will finally be sent to the cardiologist or EP for analysis. This complex process results in fewer patients receiving cardiac rhythm monitoring than would ideally receive it.
To address some of these issues with cardiac monitoring, the assignee of the present application developed various embodiments of a small, long-term, wearable, physiological monitoring device. One embodiment of the device is the Zio@ Patch. Various embodiments are also described, for example, in U.S. Pat. Numbers 8,150,502, 8,160,682 8,244,335, 8,560,046, 8,538,503, 9,173,670, and 9,597,004, and U.S. Pat. Pub. No. 2018/0289274 Al, the full disclosures of which are hereby incorporated herein by reference. Generally, the physiological patch-based monitors described in the above references fit comfortably on a patient’s chest and are designed to be worn for at least one week and typically two to three weeks. The monitors detect and record cardiac rhythm signal data continuously while the device is worn, and this cardiac rhythm data is then available for processing and analysis.
These smaller, long-term, patch-based physiological monitoring devices provide many advantages over prior art devices. At the same time, further improvements are desired. One of the most meaningful areas for improvement is to offer more timely notice of critical arrhythmias to managing clinicians. The hallmark of these initial embodiments was that — for reasons of performance, compliance and cost - the device only recorded information during the extended wear period, with analysis and reporting occurring after the recording completed. Thus, a desirable improvement would be to add the capability of either real-time or timely analysis of the collected rhythm information. While diagnostic monitors with such timely reporting capabilities currently exist, they require one or more electrical components of the system to be either regularly recharged or replaced. These actions are associated with reduced patient compliance and, in turn, reduced diagnostic yield. As such, a key area of improvement is to develop a physiologic monitor that can combine long-term recording with timely reporting without requiring battery recharging or replacement.
Patient compliance and device adhesion performance are two factors that govern the duration of the ECG record and consequently the diagnostic yield. Compliance can be increased by improving the patient’s wear experience, which is affected by wear comfort, device appearance, and the extent to which the device impedes the normal activities of daily living. Given that longer ECG records provide greater diagnostic yield and hence value, improvements to device adhesion and patient compliance are desirable.
Signal quality is important throughout the duration of wear, but may be more important where the patient marks the record, indicating an area of symptomatic clinical significance. Marking the record is most easily enabled through a trigger located on the external surface of the device. However, since the trigger may be part of a skin-contacting platform with integrated electrodes, the patient can introduce significant motion artifacts when feeling for the trigger. A desirable device improvement would be a symptom trigger that can be activated with minimal addition of motion artifact.
Further, it is desirable for the device to be simple and cost effective to manufacture, enabling scalability at manufacturing as well as higher quality due to repeatability in process. Simplicity of manufacture can also lead to ease of disassembly, which enables the efficient recovery of the printed circuit board for quality-controlled reuse in another device. Efficient reuse of this expensive component can be important for decreasing the cost of the diagnostic monitor.
There remain clinical scenarios where still longer-duration and lower-cost solutions may be a valuable addition to a portfolio of cardiac ambulatory monitoring options. Inspiration for a potential solution to these needs can be found in the continuous heart rate sensing functionality that is increasingly being incorporated in a variety of consumer health and fitness products, including smart watches and wearable fitness bands. Although continuous heart rate data can be used to provide the user with information about their general fitness levels, it is more both more challenging and valuable to use this data to provide meaningful information related to their health and wellness. For example, the ability to detect potential arrhythmias from continuous heart rate data would enable consumer devices incorporating heart rate sensing functionality to serve as potential screening tools for the early detection of cardiac abnormalities. Such an approach could be clinically valuable in providing a long-term, cost-effective screening method for at-risk populations, for example, heart failure patients at risk for Atrial Fibrillation. Alternatively, this monitoring approach could be helpful in the long-term titration of therapeutic drug dosages to ensure efficaciousness while reducing side effects, for example, in the management of Paroxysmal Atrial Fibrillation. Beyond cardiac arrhythmia detection, the appropriate analysis of heart rate information could also yield insight into sleep and stress applications.
Long-term ambulatory monitoring with a physiologic device, such as an adhesive patch, has a number of clinical applications, particularly when timely information about the occurrence and duration of observed arrhythmias can be provided during the monitoring period. In terms of prevalence, particularly as driven by an aging population, efficiently detecting Atrial Fibrillation (AF) remains the most significant monitoring need. This need is not just evident for patients presenting with symptoms, but also given the increased risk of stroke associated with this arrhythmia for broader, population-based monitoring of asymptomatic AF in individuals at risk due to one or more factors of advanced age, the presence of chronic illnesses like Heart Disease, or even the occurrence of surgical procedures. For the latter group, both perioperative and post-procedure monitoring can be clinically valuable, and not just for procedures targeted at arrhythmia prevention (for example, the MAZE ablation procedure, or hybrid endo and epicardial procedures, both for treatment of AF), but also for general surgeries involving anesthesia. For some applications, the goal of ambulatory monitoring for Atrial Fibrillation will sometimes be focused on the simple binary question of whether AF did occur in a given time period. For example, monitoring a patient following an ablation procedure will typically seek to confirm success, typically defined as the complete lack of AF occurrence. Likewise, monitoring a patient post-stroke will be primarily concerned with evaluating the presence of Atrial Fibrillation.
However, even in those scenarios, if AF occurs, it may be clinically meaningful to evaluate additional aspects to better characterize the occurrence, such as daily burden (% of time in AF each day), and duration of episodes (expressed, for example, as a histogram of episode duration, or as the percentage of episodes that extend beyond a specified limit, say six minutes), both either in absolute terms or in comparison to prior benchmarks (for example, from a baseline, pre-procedure monitoring result). Indeed, measuring daily AF burden, evaluating AF episode duration, and reviewing AF occurrence during sleep and waking periods, and evaluating the presence of AF in response to the degree of a patient’s physical movement can be important in a variety of clinical scenarios, including evaluating the effectiveness of drug-based treatment for this arrhythmia.
Making this information available in a timely manner during the monitoring period could allow the managing physician to iteratively titrate treatment, for example, by adjusting the dosage and frequency of a novel oral anticoagulant drug (NOAC) until management was optimized. A further example of this management paradigm is for the patient to be notified of asymptomatic AF — either directly by the device through audible or vibration-based alert, through notification from an application connected to the device, or via phone, email or text-message communication from the managing clinician — for the timely application of a “pill in the pocket” for AF management.
The theme of timely management and/or intervention is certainly evident in situations where clinically significant arrhythmias are observed, for example, asymptomatic second-degree and complete Heart Block, extended pauses, high-rate supraventricular tachycardias, prolonged ventricular tachycaridas, and ventricular fibrillation. For example, the clinical scenario where an extended pause or complete heart block causes Syncope is a particularly significant case where the availability of a timely and dependable monitoring method could reduce or even eliminate the need for in-hospital monitoring of at-risk patients. The theme can also extend to more subtle changes in morphology, for example, QT prolongation in response to medications, which has been shown to have significant cardiac safety implications. Timely awareness of such prolongation could lead, for example, to early termination of clinical studies evaluating drug safety and effectiveness or, alternatively, to adjusting the dosage or frequency as a means to eliminate observed prolongation.
Physiological Monitoring DevicesReferring to
The combination of a highly flexible body 110, including flexible electrodes and electrode traces 311, 312, with a very housing 115 may provide a number of advantages. A key advantage is high fidelity signal capture. The highly conformal and flexible wings 130, 131, electrodes and traces 311, 312 limit the transmission of external energy to the electrode-skin interface. If motion is imparted to the housing 115, for example, the system of conformal adhesion to the skin limits the extent to which that motion affects the monitored signal. Flexible electrode traces 311, 312 generally may help provide conformal contact with the subject’s skin and may help prevent electrodes 350 (electrodes 350 are not visible in
Referring now to
Battery holder 150, according to various alternative embodiments, may hold two batteries (as in the illustrated embodiment), one battery, or more than two batteries. In other alternative embodiments, other power sources may be used. In the embodiment shown, battery holder 150 includes multiple retain tabs 153 for holding batteries 160 in holder 150. Additionally, battery holder 150 includes multiple feet 152 to establish correct spacing of batteries 160 from the surface of PCBA 120 and ensure proper contact with spring fingers and/or contacts 235 and 236. Spring fingers 235 and 236 are used in this embodiment rather than soldering batteries 160 to PCBA 120. Although soldering may be used in alternative embodiments, one advantage of spring fingers 235 and 236 is that they allow batteries 160 to be removed from PCBA 120 and holder 150 without damaging either of those components, thus allowing for multiple reuses of both. Eliminating solder connections also simplifies and speeds up assembly and disassembly of monitoring device 100.
In some embodiments, upper housing member 140 may act as a patient event trigger. When a patient is wearing physiological monitoring device 100 for cardiac rhythm monitoring, it is typically advantageous for the patient to be able to register with device 100 (for example, log into the device’s memory) any cardiac events perceived by the patient. If the patient feels what he/she believes to be an episode of heart arrhythmia, for example, the patient may somehow trigger device 100 and thus provide a record of the perceived event. In some embodiments, trigger of perceived events by the patient may initiate transmission of data associated with the triggered event. In some embodiments, trigger of perceived events may simply mark a continuous record with the location of the triggered event. In some embodiments, both transmission of associated data as well as marking of the continuous record may occur. At some later time, the patient’s recorded symptom during the perceived event could be compared with the patient’s actual heart rhythm, recorded by device 100, and this may help determine whether the patient’s perceived events correlate with actual cardiac events. One problem with patient event triggers in currently available wearable cardiac rhythm monitoring devices, however, is that a small trigger may be hard to find and/or activate, especially since the monitoring device is typically worn under clothing. Additionally, pressing a trigger button may affect the electronics and/or the electrodes on the device in such a way that the recorded heart rhythm signal at that moment is altered simply by the motion caused to the device by the patient triggering. For example, pressing a trigger may jar one or both of the electrodes in such a way that the recorded heart rhythm signal at that moment appears like an arrhythmia, even if no actual arrhythmia event occurred. Additionally, there is a chance that the trigger may be inadvertently activated, for instance while sleeping or laying on the monitoring device.
In the embodiment shown in
Referring now to the embodiments in
Patient trigger input 210 may be configured to relay a signal from a patient trigger, such as upper housing member 140 described above, to PCBA 120. For example, patient trigger input 210 may be a PCB switch or button that is responsive to pressure from the patient trigger (for example, the upper surface of upper housing member portion 140). In various embodiments, patient trigger input 210 may be a surface mounted switch, a tactile switch, an LED illuminated tactile switch, or the like. In some embodiments, patient trigger input 210 may also activate an indicator, such as an LED. Certain embodiments may involve a remotely located trigger such as on a separate device or as a smart phone app.
One important challenge in collecting heart rhythm signals from a human or animal subject with a small, two-electrode physiological monitoring device such as device 100 described herein, is that having only two electrodes can sometimes provide a limited perspective when trying to discriminate between artifact and clinically significant signals. For example, when a left-handed patient brushes her teeth while wearing a small, two-electrode physiological monitoring device on her left chest, the tooth brushing may often introduce motion artifact that causes a recorded signal to appear very similar to Ventricular Tachycardia, a serious heart arrhythmia. Adding additional leads (and, hence, vectors) is the traditional approach toward mitigating this concern, but this is typically done by adding extra wires adhered to the patient’s chest in various locations, such as with a Holter monitor. This approach is not consistent with a small, wearable, long term monitor such as physiological monitoring device 100.
An alternate approach to the problem described above is to provide one or more additional data channels to aid signal discrimination. In some embodiments, for example, device 100 may include a data channel for detecting patch motion. In certain embodiments, an accelerometer or other suitable device may provide patch motion by simply analyzing the change in magnitude of a single axis measurement, or alternatively of the combination of all three axes. The accelerometer may record device motion at a sufficient sampling rate to allow algorithmic comparison of its frequency spectrum with that of the recorded ECG signal. If there is a match between the motion and recorded signal, it is clear that the device recording in that time period is not from a clinical (for example, cardiac) source, and thus that portion of the signal can be confidently marked as artifact. This technique may be particularly useful in the tooth brushing motion example aforementioned, where the rapid frequency of motion as well as the high amplitude artifact is similar to the heart rate and morphology, respectively, of a potentially life-threatening arrhythmia like Ventricular Tachycardia. Other suitable devices described herein this section and elsewhere in the specification may also be utilized to provide motion information.
In some embodiments, using the magnitude of all three axes for such an analysis would smooth out any sudden changes in values due to a shift in position rather than a change in activity. In other embodiments, there may be some advantage in using a specific axis of measurement such as along the longitudinal axis of the body to focus on a specific type of artifact introduced by upward and downward movements associated with walking or running. In a similar vein, the use of a gyroscope in conjunction with the accelerometer may provide further resolution as to the nature of the motion experienced. While whole body movements may be sufficiently analyzed with an accelerometer on its own, specific motion of interest such as rotational motion due to arm movement is sufficiently complex that an accelerometer alone might not be able to distinguish.
In addition to detecting motion artifact, an accelerometer tuned to the dynamic range of human physical activities may provide activity levels of the patient during the recording, which can also enhance accuracy of algorithmic true arrhythmia detection. Given the single-lead limitation of device 100, arrhythmias that require observation of less prominent waves (for example P-wave) in addition to rate changes such as Supraventricular Tachycardia pose challenges to both computerized algorithms as well as the trained human eye. This particular arrhythmia is also characterized by the sudden nature of its onset, which may be more confidently discriminated from a non-pathological Sinus Tachycardia if a sudden surge in the patient’s activity level is detected at the same time as the increase in heart rate. Broadly speaking, the provision of activity information to clinical professionals may help them discriminate between exercise-induced arrhythmia versus not. As with motion artifact detection, a single-axis accelerometer measurement optimized to a particular orientation may aid in more specifically determining the activity type such as walking or running. This additional information may help explain symptoms more specifically and thereby affect the subsequent course of therapeutic action.
In certain embodiments, an accelerometer with 3 axes may confer advantages beyond what magnitude of motions can provide. When the subject is not rapidly moving, 3-dimensional accelerometer readings may approximate the tilt of PCBA 120, and therefore body orientation relative to its original orientation. The original body orientation can be assumed to be in either an upright or supine position which is required for appropriate positioning and application of the device to the body. This information may aid in ruling out certain cardiac conditions that manifest as beat-to-beat morphology changes, such as cardiac alternans where periodic amplitude changes are observed, often in heart failure cases. Similar beat-to-beat morphology changes are observable in healthy subjects upon shift in body position due to the shift in heart position relative to the electrode vector, for example from an upright to a slouching position. By design, the single-channel device 100 does not have an alternate ECG channel to easily rule out potential pathological shifts in morphology, however, correlation with shifts in body orientation will help explain these normal changes and avoid unnecessary treatment due to false diagnosis.
In other embodiments, the accelerometer may also be used as a sleep indicator, based on body orientation and movement. When presenting clinical events (for example, pauses), it is diagnostically helpful to be able to present information in a manner that clearly separates events that occurred during sleep from those during waking hours. In fact, certain algorithms such as for ECG-derived respiratory rate only make sense to run when the patient is in a relatively motionless state and therefore subtle signal modulation introduced by chest movement due to breathing is observable. Respiratory rate information is useful as one channel of information necessary to detect sleep apnea in certain patient populations.
In certain embodiments, the accelerometer may also be used to detect free-falls, such as fainting. With an accelerometer, device 100 may be able to mark fainting (syncope) and other free-fall events without relying on patient trigger. In some embodiments, such free-fall event triggers may initiate transmission of associated data. In order to allow timely detection of such critical events, yet considering the battery and memory limitations of a small, wearable device such as device 100, acquisition of accelerometer readings may be done in bursts, where only interesting information such as a potential free fall is written to memory at a high sampling rate. An expansion of this event-trigger concept is to use specific tapping motions on device 100 as a patient trigger instead of or in conjunction with the button previously described. The use and detection of multiple types of tapping sequences may provide better resolution and accuracy into what exactly the patient was feeling, instead of relying on the patient to manually record their symptom and duration in a trigger log after the fact. An example of such added resolution is to indicate the severity of the symptom by the number of sequential taps.
Alternatively, in other embodiments, optical sensors may be used to distinguish between device motion and patient body motion. Further, in additional embodiments, the device may not require a button or trigger. In still more embodiments, suitable devices described herein this section or elsewhere in the specification may also be used.
Another optional data channel that may be added to physiological monitoring device 100 is a channel for detecting flex and/or bend of device 100. In various embodiments, for example, device 100 may include a strain gauge, piezoelectric sensor or optical sensor to detect motion artifact in device 100 itself and thus help to distinguish between motion artifact and cardiac rhythm data. Yet another optional data channel for device 100 may be a channel for detecting heart rate. For example, a pulse oximeter, microphone or stethoscope may provide heart rate information. Redundant heart rate data may facilitate discrimination of ECG signals from artifact. This is particularly useful in cases where arrhythmia such as Supraventricular Tachycardia is interrupted by artifact, and decisions must be made whether the episode was actually multiple shorter episodes or one sustained episode. Another data channel may be included for detecting ambient electrical noise. For example, device 100 may include an antenna for picking up electromagnetic interference. Detection of electromagnetic interference may facilitate discrimination of electrical noise from real ECG signals. Any of the above-described data channels may be stored to support future noise discrimination or applied for immediate determination of clinical validity in real-time.
With reference now to the embodiments of
Hinge portions 132 are relatively thin, even more flexible portions of flexible body 110. They allow flexible body 110 to flex freely at the area where it is joined to housing 115. This flexibility enhances comfort, since when the patient moves, housing 115 can freely lift off of the patient’s skin. Electrode traces 311, 312 are also very thin and flexible, to allow for patient movement without signal distortion. Borders 133 are portions of flexible body 110 that is thinner than immediately adjacent portions and that provide for a smooth transition from flexible body 110 to a patient’s skin, thus preventing edge-lift and penetration of dirt or debris below flexible body 110.
As shown in greater detail in
Typically, top and bottom substrate layers 300, 330 are attached to one another via adhesive placed on one or both layers 300, 330. For example, the adhesive or bonding substance between substrate layers 300, 330 may be an acrylic-based, rubber-based, or silicone-based adhesive. In other alternative embodiments, flexible body 110 may include more than two layers of flexible material.
In addition to the choice of material(s), the dimensions — thickness, length and width — of substrate layers 300, 330 may be selected based on desired characteristics of flexible body 110. For example, in various embodiments, the thickness of substrate layers 300, 330 may be selected to give flexible body 110 an overall thickness of between about 0.1 mm to about 1.0 mm. According to various embodiments, flexible body 110 may also have a length of between about 7 cm and 15 cm and a width of about 3 cm and about 6 cm. Generally, flexible body 110 will have a length sufficient to provide a necessary amount of separation between electrodes 350. For example, in one embodiment a distance from the center of one electrode 350 to the center of the other electrode 350 should be at least about 6.0 cm and more preferably at least about 8.5 cm. This separation distance may vary, depending on the application. In some embodiments, substrate layers 300, 330 may all have the same thickness. Alternatively, the two substrate layers 300, 330 may have different thicknesses.
As mentioned above, hinge portions 132 allow the rigid housing 115 to lift away from the patient while flexible body 110 remains adhered to the skin. The functionality of hinge portions 132 is critical in allowing the device to remain adhered to the patient throughout various activities that may stretch and compress the skin. Furthermore, hinge portions 132 allow for significantly improved comfort while wearing the device. Generally, hinge portions 132 will be sufficiently wide enough to provide adequate lift of rigid housing 115 without creating too large of a peel force on flexible body 110. For example, in various embodiments, the width of hinge portion 132 should be at least about 0.25 cm and more preferably at least about 0.75 cm.
Additionally, the shape or footprint of flexible body 110 may be selected based on desired characteristics. As seen in
While the illustrated embodiments of
Adhesive layer 340 is an adhesive that is applied to two portions of the bottom surface of bottom substrate layer 330, each portion corresponding to one of wings 130, 131. Adhesive layer 340 thus does not extend along the portion of bottom substrate layer 330 upon which housing 115 is mounted. Adhesive layer 340 may be made of any suitable adhesive, although certain adhesives have been found to be advantageous for providing long term adhesion to patient skin with relative comfort and lack of skin irritation. For example, in one embodiment, adhesive layer 340 is a hydrocolloid adhesive. In another embodiment, the adhesive layer 340 is comprised of a hydrocolloid adhesive that contains naturally-derived or synthetic absorbent materials which take up moisture from the skin during perspiration.
With reference now to
As discussed above, in some embodiments, adhesive layer 340 may cover a portion of the underside of lower substrate layer 330, such that at least a portion of the bottom side of flexible body 110 does not include adhesive layer 340. As seen in
Flexible body 110 further includes two electrode traces 311, 312 sandwiched between upper substrate layer 300 and lower substrate layer 330. Each electrode trace 311, 312 may include an electrode interface portion 310 and an electrocardiogram circuit interface portion 313. As illustrated in the embodiments of
The material and thickness of electrode traces 311, 312 are important for providing a desired combination of flexibility, durability and signal transmission. For example, in one embodiment, electrode traces 311, 312 may include a combination of silver (Ag) and silver chloride (AgCl). The silver and silver chloride may be disposed in layers. For example, one embodiment of electrode traces 311, 312 may include a top layer of silver, a middle layer of carbon impregnated vinyl, and a bottom (patient-facing) layer of silver chloride. In another embodiment, both top and bottom layers of electrode traces 311, 312 may be made of silver chloride. In one embodiment, the top and bottom layers may be applied to the middle layer in the form of silver ink and silver chloride ink, respectively. In an alternative embodiment, each electrode trace may include only two layers, such as a top layer of silver and a bottom layer of silver chloride. In various embodiments, the material of a bottom layer of each electrode trace 311, 312, such as AgCl, may be selected to match the chemistry of the hydrogel electrodes 350 and create a half-cell with the body of the subject.
The thickness of the electrode traces 311, 312 may be selected to optimize any of a number of desirable properties. For example, in some embodiments, at least one of the layers of electrode traces 311, 312 can be of a sufficient thickness to minimize or slow depletion of the material from an anode/cathode effect over time. Additionally, the thickness may be selected for a desired flexibility, durability and/or signal transmission quality.
As mentioned above, in some embodiments, top gasket 370 and bottom gasket 360 may be attached upper substrate 300 and lower substrate 330 of flexible body 110. Gaskets 360, 370 may be made of any suitable material, such as urethane, which provides a water tight seal between the upper housing member 140 and lower housing member 145 of housing 115. In one embodiment, top gasket 370 and/or bottom gasket 360 may include an adhesive surface.
In particular embodiments, the adhesive layer 340 may generally comprise a top surface adhered to a bottom surface of the bottom substrate layer 330 (such as shown in
In some embodiments, the inclusion of channels 341 within the adhesive layer 340 may generally make the adhesive layer 340 more conformable to the surface of the subject (e.g., the skin). For instance the adhesive layer 340 may better absorb bending strain due to the presence of the plurality of channels 341, which may promote or improve adhesion of the physiological monitoring devices (such as described herein this section or throughout the specification) to the subject, particularly on a non-flat surface and/or on a portion of the body expected to experience dynamic conformational changes. The plurality of channels 341 can be arranged to promote customized movement or strain of the flexible body 110 (as shown in
In some embodiments, the plurality of channels 341 may comprise horizontal rows or columns of channels 341 that connect the top and bottom surfaces of the adhesive layer 340. The rows or columns may be arranged in a relatively uniformly spaced manner. The rows or columns may extend from and/or to the periphery of the adhesive layer 340. The rows or columns may extend across the adhesive layer to another point on the periphery of the adhesive layer 340 dividing the adhesive layer into thin strips 342.
In some embodiments, the plurality of channels 341 may comprise both rows and columns. The rows and columns may be arranged in a uniformly spaced manner (e.g., substantially perpendicular to each other) to form a lattice network which divides the adhesive layer 340 into small islands 343 of adhesive material. The islands 343 may have rectangular configurations (e.g., a perpendicular lattice network), diamond configurations, trapezoidal configurations, pentagonal configurations, hexagonal configurations, other polygonal configurations, etc.
In some embodiments, the strips 342 and/or islands 343 of the adhesive material may be interconnected by a network of thin webbing 345. The webbing 345 may comprise thin, flexible strands of material coupling the strips 342 and/or islands 343 together. In some embodiments, the webbing 345 may comprise nylon, cotton, polyester, and/or another suitable material. In some embodiments, the webbing 345 may extend through the strips 342 and/or islands 343, as schematically illustrated in
In some embodiments, the channels 341 may be arranged in a radial pattern (e.g., a linear spoke pattern). In some embodiments, the channels 341 may be non-linear (e.g., a coaxial arrangement of ring-shaped channels 341). For example, the channels 341 may be radially arranged in the horizontal plane in a spiraling fashion, as schematically illustrated in
In some embodiments, the strips 342 and/or islands 343 of adhesive material may be affixed to a thin backing layer. For instance, in some embodiments the strips 342 and/or islands 343 may be formed directly on a bottom surface of the bottom substrate layer 330. In some embodiments, the adhesive layer 340 may be formed on a removable backing layer which is removed from the adhesive layer 340 after it is transferred to the bottom substrate layer 330 of the flexible body 110. In some embodiments, the adhesive layer 340 may be formed free of any backing layer (e.g., formed around the webbing 345). In some embodiments, the channels 341 may be formed during fabrication of the adhesive layer 340. For instance, the adhesive matrix of the adhesive layer 340 may be formed around a die imparting the shape of the channels 341. In some embodiments, the channels 341 may be formed after fabrication of the adhesive layer 340. For instance, after fabrication the adhesive layer 340 may be perforated or vertical channels 341 may be punched through the adhesive layer 340. In some embodiments, tubes (e.g., capillary tubes) may be inserted into and through the adhesive layer 340 to form vertical channels 341. In some embodiments, horizontal strips of adhesive layer may be removed (e.g., by cutting) leaving behind strips 342 and/ or islands 343 of the adhesive material. In some embodiments, the adhesive matrix of the adhesive layer 340 may be formed on a backing layer or substrate, which may optionally be removed from the adhesive layer 340 prior to adhering the adhesive layer 340 to the bottom substrate layer 330 (such as shown in
In some embodiments, the adhesive layer 340 may comprise moisture wicking materials (e.g., water adsorbing materials) and/or may be coupled to a layer of moisture wicking materials. The moisture wicking materials may comprise a matrix of moisture wicking fibers. The moisture wicking materials may comprise wool, nylon, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE), thermoplastic elastomers (TPE), and/or any other suitable water-absorbent material. In some embodiments, the moisture wicking materials may be hydrophobic and/or hydrophilic, such that the core can retain the water, move it outward/upward and the outer sheath of the fiber can insulate the surrounding adhesive from moisture. The moisture wicking material may be formed as a layer above the top surface of the adhesive layer 340 (e.g., between the adhesive layer 340 and the bottom substrate layer 330) or used as capillary tubes. The moisture wicking material may be used to partially or entirely fill or line one or more of the plurality of channels 341. In some implementations, the inclusion of moisture wicking materials may facilitate drawing moisture from the surface of the subject through the channels 341 and/or into the adhesive layer 340 and/or upper substrate layers, such as through a moisture vapor permeable layer. In certain embodiments, the moisture may be moved out to the uppermost surface and optionally evaporated through a moisture vapor permeable layer, and/or to the outer edges of the adhesive for evaporation. The inclusion of moisture wicking materials may allow for the storage of moisture within the adhesive layer 340 away from the interface between the bottom of the adhesive layer 340 and the skin of the subject where the moisture is likely to promote delamination of the adhesive layer 340. The storage of moisture within the adhesive layer 340 or other layers of the physiological monitoring device 100 may be advantageous when the moisture from the surface of the subject cannot be transpired through the device 100 as quickly as it is generated, preventing or inhibiting the buildup of moisture between the bottom surface of the adhesive layer 340 and the skin. In some embodiments the wicking and/or fibers present in the materials may be oriented such that moisture is pulled outward radially from the adhesive. At outer areas of the adhesive or where perforations are present, a moisture sink may be created which maximizes surface area of those fibers, allowing for evaporation of the moisture that accumulates from within.
The peripheral edge of the adhesive layer 340 may promote undesired adhesion of materials to the periphery of the adhesive layer 340. Particularly in examples comprising a border 133, portions of the flexible body 110 may become adhered to the peripheral edge of the adhesive layer 340. For instance, the bottom surface of the top substrate layer 300 forming the border 133 may become adhered to the peripheral edge of the adhesive layer 340. Adhesion of substrate layers of the flexible body 110 to the peripheral edge of the adhesive layer 340 may deform the flexible body 110 from its intended configuration and/or may interfere with the proper mechanics and distribution of stress throughout the flexible body 110 which could inhibit or decrease the duration of long-term adhesion between the device 100 and the skin. Additionally or alternatively, dirt, debris, or adjacent portions of skin may become adhered to the peripheral edge of the adhesive layer 340 which may also interfere with long-term adhesion. Adhesion of foreign material to the peripheral edge of the adhesive layer 340 may promote or lead to loss of adhesion of material between the skin of the subject and the bottom surface of the adhesive layer 340. Delamination of the adhesive layer 340 may tend to initiate at the edge of the adhesive layer 340. If the edge begins to delaminate from the skin, the border 133 or other materials which are adhered to the peripheral edge may become tucked under the adhesive layer 340 between the bottom surface and the skin. For instance, the border 133 may begin to fold under the adhesive layer 340. The wedging of materials between the bottom surface of the adhesive layer 340 and the skin of the subject may apply a stress to the adhesive layer 340 and/or deform the adhesive layer 340 which may lead to further delamination, such that peeling may begin to nucleate from the peripheral edge. Adhesion between the bottom surface of the adhesive layer 340 and the external material may continue to draw the material in under the adhesive layer 340, creating an “inchworm effect,” particularly where the material experiences a stronger adhesion to the adhesive layer 340 than the skin of the subject experiences relative to the adhesive layer 340.
In some embodiments, adhesion to the peripheral edge of the adhesive layer 340 may be prevented or inhibited by lining the peripheral edge of the adhesive layer 340 with a non-adhesive material in the form of a blocking liner. In certain examples, no adhesive may be applied to the periphery such that a blocking liner may not be used to prevent or inhibit adhesion to the peripheral edge. Where no adhesive is used at the periphery, adhesive may be printed to a carrier film, but not to the periphery. In some embodiments, the non-adhesive material may comprise a silicone (e.g., polydimethylsiloxane (PDMS)) and/or any other suitable material. The non-adhesive lining may outline the entire periphery of the adhesive layer 340 or may outline continuous and/or discontinuous portions of the periphery. The non-adhesive lining may comprise an annular (e.g., ring-shaped) configuration. An inner diameter of the non-adhesive lining may be generally equal to an outer diameter of the adhesive layer 340. The non-adhesive liner may be generally flexible or elastic such that it may conform to the peripheral edge of the adhesive layer 340 and/or may experience dynamic strain as the subject moves without delaminating from the adhesive layer 340. The non-adhesive lining may extend from the top of the peripheral edge to the bottom of the peripheral edge or may extend along a portion of the thickness (e.g., a top portion, a bottom portion, and/or an intermediate portion). The non-adhesive lining may comprise a width extending from the peripheral edge of the adhesive layer 340 to an outer edge of the lining. The width may be no greater than approximately 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm. In some embodiments, the inner diameter of the non-adhesive liner may comprise an adhesive surface, which may facilitate the adhesion of the non-adhesive liner to the peripheral edge of the adhesive layer 340. In some embodiments, the bottom surface of the non-adhesive lining may be non-adhesive creating a buffer between the bottom surface of the adhesive layer 340 and the outer diameter of the non-adhesive lining. In some embodiments, the bottom surface of the non-adhesive lining may be adhesive and configured to adhere to the skin of the subject. The non-adhesive liner may prevent or inhibit the adhesion of any portion of the flexible body 110, any other materials, or adjacent portions of skin form adhering to the peripheral edge of the adhesive layer 340 and/or may prevent or inhibit materials from inserting themselves between the bottom surface of the adhesive layer 340 and the skin of the subject. The non-adhesive liner may promote or increase the duration of long-term adhesion of the adhesive layer 340 to the skin of the subject.
In some embodiments, a peripheral area of the adhesive layer 340 may comprise a tapered thickness. The thickness of the adhesive layer 340 may decrease from a central location radially outward toward the peripheral edge of the adhesive layer 340, and/or vice versa. In some embodiments, the central location may be a generally central point of the adhesive layer 340 such that the width is variable across an entire radius of the adhesive layer 340. In some embodiments, a central region of the adhesive layer 340 may comprise a uniform thickness and a peripheral annular region may comprise a tapered thickness, and/or vice versa. In some embodiments, particularly in embodiments in which the adhesive layer 340 comprises a generally circular surface area, the thickness of the adhesive layer 340 may be uniform in a circumferential direction or at points positioned equal distances from the peripheral edge. In some embodiments, at least the outer most 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm of the adhesive layer 340 may comprise a tapering thickness. A more gradual taper may provide for more advantageous mechanics and distribute stresses through the adhesive layer 340 more uniformly. The thickness of the peripheral edge of the adhesive layer 340 may be no greater than approximately 5%, 10%, 15%, 20%, 25%, 30%, 40%, or 50% of a maximal thickness of the adhesive layer 340 (e.g., at a central portion). In some embodiments, the thickness may taper down to a generally pointed edge of negligible thickness. The reduced thickness of the peripheral edge may prevent or prohibit adhesion of the flexible body 110, any other materials, or adjacent portions of skin form adhering to the peripheral edge of the adhesive layer 340 and/or may prevent or inhibit materials from inserting themselves between the bottom surface of the adhesive layer 340 and the skin of the subject. The tapered peripheral edge may promote or increase the duration of long-term adhesion of the adhesive layer 340 to the skin of the subject.
In various embodiments, such as those shown in
In some embodiments, the wings 130, 131 may comprise structural reinforcement members (not shown) along peripheral edges of the wings 130, 131. The structural support members may comprise thin wire-like configurations. The structural reinforcement members may be disposed in or in between any layers of the wings 130, 131, such as the top substrate layer 300 or the bottom substrate layer 330. In some embodiments, the structural reinforcement members may be disposed in the borders 133 outside and around the adhesive layers 340. The structural reinforcement members may maintain or preserve the general shape (e.g., outer outline) of the wings 130, 131 even if the adhesive layer 340 begins to peel, deteriorate, and/or break down along the edges. The structural support members may comprise a relatively stiff metal or plastic. In some embodiments, the structural support member may comprise a shape memory material (e.g., nitinol). The shape memory properties of the shape memory structural support member may resist permanent deformation of the wings 130, 131 and may help prevent, for example, wrinkling of the wings and/or the border 133 tucking under the adhesive layer 340.
In some embodiments, the support layer may comprise at least two overlapping layers of material (e.g., top substrate layer 300 and bottom substrate layer 330). In some embodiments, the bottom most substrate layer (e.g., bottom substrate layer 330) and/ or the top most substrate layer (e.g. top substrate layer 300) of the flexible body 110 may comprise more than one layer. The various layers may comprise polyethylene terephthalate (PET) and/or polyurethane (PU). In various embodiments, layers comprising PET may provide structural support to the flexible body. PET may be the most rigid or stiff material present throughout the layers of the flexible body 110. The layer providing structural support may also provide resistance to wrinkling of adjacent more wrinkle-prone (e.g., less rigid) layers. In various embodiments, layers comprising polyurethane may provide a conformable and/or breathable barrier to the flexible body 110, 310. Polyurethane may be the least rigid material or at least not the most rigid material present throughout the layers of the flexible body 110. The polyurethane may generally create a seal against water preventing water from entering through the ambient environment and penetrating between the adhesive layer 340 and the skin of the subject. The barrier layer may be particularly advantageous for allowing the subject to shower. Providing a shower-compatible physiological monitoring device may improve user compliance and/or promote or increase the duration of long-term wear. The polyurethane layer may be generally breathable allowing transpiration to occur through the polyurethane layer, particularly where the polyurethane layer is relatively thin. In some embodiments, a perforated PET layer may be positioned between the adhesive layer 340 and the polyurethane layer. In embodiments, a polyurethane layer may be positioned between the adhesive layer 340 and a perforated PET layer. In some embodiments, the bottom most substrate layer 330 may be integrated with the adhesive layers, for example in a spun polyurethane that enables the adhesive to be formed around the lattice or mesh structure provided by the substrate.
In various embodiments, the adhesive layer (e.g., adhesive layer 340, 240, or any other adhesive layer described herein) may be replaceable. Replacing the adhesive layer 340 may prolong the duration of wear of the physiological monitoring device 100 as a fresh adhesive layer 340 may supplant an adhesive layer 340 which is beginning to or has lost a substantial ability to adhere the device 100 to the skin of the subject. To replace an adhesive layer 340, the top surface of the adhesive layer 340 may be separated from the bottom surface of the substrate layers of the flexible body 110 (e.g., the bottom surface of the bottom substrate layer 330). The physiological monitoring device 100 may be removed from the body of the subject and then the adhesive layer 340 separated from the flexible body 110. The adhesive layer 340 may be easiest to remove by peeling the adhesive layer 340 from the flexible body 110 beginning at an inside corner of the adhesive layer 340 (e.g., a corner closest to the housing 115. A specialized removal device may be provided for facilitating the removal of the adhesive layer 340. For instance, the removal device may comprise a thin flat blade configured to be inserted between the adhesive layer 340 and the flexible body 110. The removal device may comprise a handle extending from the blade. The handle may extend from the blade at an angle such that the blade may be positioned parallel to the flexible body which may be supported on a flat surface and the handle may be positioned and held above the flat surface. For example, the removal tool may be used to separate a corner of the adhesive layer 340 from the flexible body 110 and then the corner of the adhesive layer 340 may be used to pull or peel the remainder of the adhesive layer 340 from the flexible body 110. The removal tool or a separate removal tool may comprise a means for grasping the adhesive layer 340 after it has been partially separated from the substrate layers of the flexible body 110 such that the removal tool may be used to pull or peel the adhesive layer 340 from the substrate layers of the flexible body 110. The replacement adhesive layer 340 may be applied to the flexible body 110 in the same or similar manner as when the original adhesive layer 340 is applied to the substrate layers of the flexible body 110 during manufacture or assembly of the physiological monitoring device 100. For example, the adhesive layer 340 may be formed on a backing layer on the bottom surface of the adhesive layer 340, which can be removed after the top surface of the adhesive layer is adhered to the flexible body 110. In some embodiments, the replacement adhesive layer may be applied to the flexible body 110 through the use of a template or tool to enable easy and accurate positioning relative to the features on flexible body 110.
In some embodiments, the adhesive layer 340 may be comprised of multiple layers. In certain examples, if experiencing adhesion failure or for other suitable reasons, the user may remove the physiological monitoring device 100, and remove the bottom-most layer of 340 that was in direct contact with the skin. This removed layer may be the entire surface of 340, exposing a fresh adhesive layer of 340 below, or it might be an annular area of 340, exposing a fresh layer in only one portion of the adhesive, or some other smaller area that is less than the entire area. In certain embodiments, the layer of “used” adhesive may take the shape of a pattern distributed across the surface of adhesive 340, resulting in a distributed mix of fresh adhesive and “used” adhesive across its surface. Similar to replacement of the adhesive, refreshing the adhesive through removal of some or all of the most recent skin-contacting layer may have the effect of extending wear duration. The multiple layers of 340 in such an embodiment may be constructed through a combination of adhesive and release liner, where the release liner may be siliconized for releasability on the top surface but adhered more permanently on its bottom surface or vice-versa. The siliconization may be tuned to allow for intentional layer removal, without causing undue challenges in maintaining adhesion on the body. Additionally, in certain examples, adhesive layer removal may be enabled through the use of pull tabs built into the layers. Further, removal may also be enabled through a tool that adheres more strongly to the “used” adhesive than the release liner is adhered to the layer below it. In embodiments, the adhesive may be integrated within a lattice or mesh substrate, enabling separation from other layers of adhesive without losing integrity. In some embodiments, the physiological monitoring device 100 may have an annular ring of adhesive exposed without removal from the user’s skin. An inner shape of adhesive on each wing may remain adhered while an annular ring was removed, exposing fresh adhesive and enabling extended wear. Adhesion failure often begins at the outermost edges of the adhesive, therefore this approach of refreshing only an annular ring on the outer layer may help extend wear duration while minimizing interruption of data collection and also increasing likelihood that the user continues to wear the device.
In some embodiments, a pull string (not shown) may be sandwiched between the adhesive layer 340 and the bottom substrate layer 330, embedded in the adhesive layer 340, or partially embedded in the adhesive layer 340 and partially sandwiched between the adhesive layer 340 and the bottom substrate layer 330. The pull string may have a free tail end at a proximal of the pull string extending beyond a peripheral edge of the adhesive layer 340. The pull string may extend across a surface area of the adhesive layer 340 according to a particular pattern. In some embodiments, the pull string may closely follow or trace the peripheral edge of the adhesive layer 340. In some embodiments, the pull string may closely follow an outer diameter of the electrode(s) 350. In some embodiments, the pull string may form a substantially closed circuit around a surface area of the adhesive layer 340. For instance, a distal tail end may be positioned in close proximity to the proximal free tail end. The distal tail end may freely extend beyond the peripheral edge of the adhesive layer 340 as does the proximal free tail end or it may be positioned within the surface area of the adhesive layer 340. The pull string may be configured to help remove the removable adhesive layer from substrate layer 330 or from another layer within adhesive layer 340. Pulling the free tail end of the pull string (e.g., pulling the free tail end of the pull string across a bottom surface of the adhesive layer 340) may cause the pull string to cut through the adhesive layer 340 and/or separate (e.g., lift off) the adhesive layer 340 or portions thereof from the substrate layers of the flexible body 110. In some embodiments, the pull string may remove a peripheral border area (e.g., an annular area) of the adhesive layer 340 from an inner central portion of the adhesive layer 340. The border area and/or other portions of the adhesive layer 340 may be lifted off the bottom substrate layer 330 or other layers within adhesive layer 340. Forming a division between different portions of the adhesive layer 340 may facilitate removal of the portions from the bottom substrate layer 330. The new severed edges created in the adhesive layer 340 by the pull string may provide starting locations for peeling the adhesive layer 340 from the bottom substrate layer 330. These edges may be easier to separate from the natural or original peripheral edges of the adhesive layer 340, particularly where the natural edges are flush with the edges of the bottom substrate layer 330. It may be easier to lift the severed edge of the adhesive layer off of an underlying surface such as the bottom substrate layer 330 than to separate two thin edges from each other at a peripheral edge of the flexible body 110. In some embodiments, pulling the pull string may at least partially lift the severed edge of the adhesive layer 340 off of the bottom surface of the bottom substrate layer 330 making subsequent peeling of the adhesive layer 340 easier. In some embodiments, the adhesive layer 340 may be naturally segmented or segmentable along paths not formed by a pull string. For instance, the adhesive layer 340 may be fabricated to be particularly frangible along a similar outline as the pull string, such as by disposing a path of perforations across the surface area of the adhesive layer 340. The pull string may be used in combination with other removal methods and/or tools disclosed elsewhere herein.
In some embodiments, the adhesive layer 340 may extend entirely to the edge or border of the substrate layers (e.g., including top substrate layer 300) such that the top surface of the adhesive layer 340 is adhered to the bottom surface of the border 133 as well as the bottom surface of the bottom substrate layer 330. In some embodiments, the flexible body 110 may not comprise a border 133 and the adhesive layer may extend to the edge of the bottom substrate layer 330. Embodiments that comprise replaceable adhesive layer 340 may be particularly suitable for adhesive layers 340 that extend to the outer edge or border of the flexible body 110.
In some embodiments, a housing 415 may include sensing electrodes 350, as shown in
The flexible body 410 of the physiological monitoring device 400 may be replaceable. The flexible body 410 may be removed from the housing 415 and electrode traces 411, 412 and a replacement flexible body 410 may be reapplied in the same manner as the original was assembled. In certain embodiments discussed herein, the flexible body 410 may include the electrode traces 411, 412 and flexible body 410 may be removed from the housing 415 to be replaced by another in the same location. This embodiment of the physiological monitoring device 400 may provide a convenient method for replacing the adhesive layers of the physiological monitoring device 400 after the adhesive layers have begun to wear and/or peel, allowing for a longer duration of use of the device 400.
Physiological Monitoring DeviceIn certain embodiments, an additional visualization pattern 710 may extend through the wing. The visualization pattern 710 may be in any suitable size or shape to outline the electrode trace and frame the shape of the wings, for example, the visualization pattern 710 may be in the form of lines, such as rounded lines to reflect the contours of the electrode trace and the shape of the wings. In certain embodiments, there may be one, two, three, four, or more lines. In some embodiments, the visualization pattern may be formed from a pattern of dots, shapes or other combinations such that the visual cleanliness of the device is maintained as the otherwise clear adhesive layer becomes less visually acceptable to the user through the course of the wear period (e.g. if the adhesive layer picks up foreign material and/or becomes cloudy with absorption of moisture). In certain embodiments, the visualization pattern may have another functional purpose of alerting the user to how long they have been wearing the device, for example, by changing color over time or wearing down. This change in appearance may alert the user to remove the device at the right time.
As shown in
For example,
In some embodiments, the top substrate layer 300 may be replaced by the subject at some period of time into the intended wear period, such as about: 6 hours, 12 hours, 1 day, 2 days, 4 days, 1 week, or a period longer than one week, in order to extend duration of wear as well as refresh the aesthetic appearance of the device. In certain embodiments the top substrate layer 300 may exist as two separate pieces without intersecting housing 114, as shown in
The arrows in
In some embodiments, placement of adhesive-backed top substrate layer 300 may be facilitated through application of a single monolithic piece without features or cutouts. This type of layer could be applied over the top of an entire device 100 for additional securement during wear, or placed after removal of adhesive-backed top substrate layer 300 as a replacement. In other embodiments, the adhesive-backed top substrate layer for additional securement or replacement may be a single piece with feature cutouts such as shown in
With reference now to the embodiment of
With continued reference to
Referring now to the embodiment of
With reference now to the embodiments of
It is desirable that PCBA 120 is sufficiently rigid to prevent bending and introducing unwanted artifact into the signal. In certain embodiments, an additional mechanism to reduce and prevent unwanted bending of PCBA 120 may be used. This mechanism is shown in
Referring to
Labels 820, 840 may be any suitable labels and may include produce name(s), manufacturer name(s), logo(s), design(s) and/or the like. They may be removable or permanently attached upper housing member 140 and/or lower housing member 145, although typically they will be permanently attached, to avoid unregulated reuse and/or resale of the device by an unregistered user. Device identifier 830 may be a barcode sticker, computer readable chip, RFID, or the like. Device identifier 830 may be permanently or removably attached to PCBA 120, flexible body 110 or the like. In some embodiments, it may be beneficial to have device identifier 830 stay with PCBA 120.
Referring now to the embodiments of
Referring now to
In a next step, referring to
In certain embodiments, when a desired monitoring period has ended, such as about 14 to 21 days in some cases, a patient (or physician, nurse or the like) may remove physiological monitoring device 100 from the patient’s skin, place device 100 in a prepaid mailing pouch, and mail device 100 to a data processing facility. At this facility, device 100 may be partially or completely disassembled, PCBA 120 may be removed, and stored physiological data, such as continuous heart rhythm information, may be downloaded from device 100. The data may then be analyzed by any suitable method and then provided to a physician in the form of a report. The physician may then discuss the report with the patient. PCBA 120 and/or other portions of device 100, such as housing 115, may be reused in the manufacture of subsequent devices for the same or other patients. Because device 100 is built up as a combination of several removably coupled parts, various parts may be reused for the same embodiment or different embodiments of device 100. For example, PCBA 120 may be used first in an adult cardiac rhythm monitor and then may be used a second time to construct a monitor for sleep apnea. The same PCBA 120 may additionally or alternatively be used with a differently sized flexible body 110 to construct a pediatric cardiac monitor. Thus, at least some of the component parts of device 100 may be interchangeable and reusable.
In further embodiments described in greater detail below, the monitoring data may be transmitted wirelessly or through other communication mediums to be analyzed, rather than requiring physical shipment of the device for analysis and reporting.
Advantageously, physiological monitoring device 100 may provide long term adhesion to the skin. The combination of the configuration of flexible and conformal body 110, the watertight, low profile configuration of housing 115, and the interface between the two allows device 100 to compensate for stress caused as the skin of the subject stretches and bends. As a result, device 100 may be worn continuously, without removal, on a patient for as many as 14 to 21 days or more. In some cases, device 100 may be worn for greater or less time, but 14 to 21 days may often be a desirable amount of time for collecting heart rhythm data and/or other physiological signal data from a patient.
In various alternative embodiments, the shape of a particular physiological monitoring device may vary. The shape, footprint, perimeter or boundary of the device may be circular, an oval, triangular, a compound curve or the like, for example. In some embodiments, the compound curve may include one or more concave curves and one or more convex curves. The convex shapes may be separated by a concave portion. The concave portion may be between the convex portion on the housing and the convex portion on the electrodes. In some embodiments, the concave portion may correspond at least partially with a hinge, hinge region or area of reduced thickness between the body and a wing.
While described in the context of a heart monitor, the device improvements described herein are not so limited. The improvements described in this application may be applied to any of a wide variety of physiological data monitoring, recording and/or transmitting devices. The improved adhesion design features may also be applied to devices useful in the electronically controlled and/or time released delivery of pharmacological agents or blood testing, such as glucose monitors or other blood testing devices. As such, the description, characteristics and functionality of the components described herein may be modified as needed to include the specific components of a particular application such as electronics, antenna, power supplies or charging connections, data ports or connections for down loading or off-loading information from the device, adding or offloading fluids from the device, monitoring or sensing elements such as electrodes, probes or sensors or any other component or components needed in the device specific function. In addition or alternatively, devices described herein may be used to detect, record, or transmit signals or information related to signals generated by a body including but not limited to one or more of ECG, EEG and/or EMG. In certain embodiments, additional data channels can be include to collect additional data, for example, device motion, device flex or bed, heart rate and/or ambient electrical or acoustic noise.
The physiological monitors described above and elsewhere in the specification may further be combined with methods and systems of data processing and transmission that improve the collection of data from the monitor. Further, the methods and systems described below may improve the performance of the monitors by enabling timely transmission of clinical information while maintaining the high patient compliance and ease-of-use of the monitor described above. For example, the methods and systems of data processing and transmission described herein this section of elsewhere in the specification may serve to extend the battery life of the monitor, improve the accuracy of the monitor, and/or provide other improvements and advantages as described herein this section or elsewhere in the specification.
Device Monitoring and Clinical Analysis PlatformThe systems and methods described in detail below, in reference to the embodiments of
The R-R interval time series 902 data may be extracted from or received from a dedicated heart rate monitor such as a heart rate chest strap or heart rate watch, or a wearable health or fitness device 906, 908 that incorporates heart rate sensing functionality. Alternatively, the R-R interval time series 902 may be derived from a wearable patch designed to measure an ECG signal 904 (for instance, by locating the R peaks in the ECG using a QRS detection algorithm). Furthermore, the R-R interval time series 902 may be estimated from an alternative physiological signal such as that obtained from photoplethysmography (PPG). In this scenario, the peak-to-peak interval time series determined from the PPG signal may be used as an accurate estimate of the R-R interval time series.
In one aspect, a cardiac rhythm inference system 910 is implemented as a cloud service or server-based system that exposes an application programming interface (API) enabling R-R interval time series data or other signal data to be transmitted to the system (for instance, via HTTP) and the resulting cardiac rhythm information to be returned to the calling software. The R-R interval time series data 902 or other signal data may be transmitted to the cloud service directly from the heart-rate monitoring device itself, or indirectly via a smartphone 912, tablet or other internet-enabled communication device 914 that can receive data from the heart rate monitoring device in either a wireless or wired manner. In addition, the R-R interval time series data 902 or other signals may be transmitted from a server 916 that stores the data for a number of users.
In some embodiments, a cardiac rhythm inference system 910 is provided through a software library that can be incorporated into a standalone application for installation and use on a smartphone, tablet or personal computer. The library may provide identical functionality to that of the inference service, but with R-R interval time series data 902 or other signal data transmitted directly through a functional call, as opposed to through a web service API.
In certain embodiments, a cardiac rhythm inference system may accept a plurality of R-R interval time series measured from devices of a given user 918, in addition to an individual R-R interval time series 902. In this scenario, the system computes the frequency and duration of each of the cardiac rhythm types inferred from the collection of time series data. These results may then be used to estimate confidence statistics for each type of cardiac rhythm based on the frequency and duration of occurrence of that rhythm across the various time series. In addition, the rhythm confidence statistics may be updated in a sequential manner for each separate call of the inference service. Furthermore, in some embodiments, the cardiac rhythm information inferred by the system may be provided back to the calling software only in the event that the confidence score for a given rhythm type exceeds a pre-determined threshold value.
In particular embodiments, a cardiac rhythm inference system 910 may accept additional sources of data, generally described as alternate sensor channels, in addition to R-R interval time series data, to enhance the accuracy and/or value of the inferred results. One additional source of data includes user activity time series data, such as that measured by a 3-axis accelerometer concurrently with the R-R interval time series measurements. In addition, the system may accept other relevant metadata that may help to improve the accuracy of the rhythm analysis, such as user age, gender, indication for monitoring, pre-existing medical conditions, medication information, medical history and the like, and also information on the specific day and time range for each time series submitted to the system. Furthermore, the measurement device might also provide some measure of beat detection confidence, for example, for each R-Peak or for sequential time periods. This confidence measure would be based on analysis the recorded signal that, in typical embodiments, would not be recorded due to storage space and battery energy requirements. Finally, in the particular case that the R-R interval time series data are derived from an ECG signal, the system may accept additional signal features computed from the ECG. These features may include a time series of intra-beat interval measurements (such as the QT or PR interval, or QRS duration), or a time series of signal statistics such as the mean, median, standard deviation or sum of the ECG signal sample values within a given time period.
The various aspects described above could be used either individually or in combination to provide an application providing insights into an individual’s health, stress, sleep, fitness and/or other qualities.
Some embodiments concern a system for selective transmission of electrocardiographic signal data from a wearable medical sensor. Current wearable sensors, such as the iRhythm ZioPatch™ 904, and further described above are capable of recording a single-lead electrocardiogram (ECG) signal for up to two weeks on a single battery charge. In many situations however, it is desirable for the sensor to be able to transmit, in real-time or near real-time, specific sections of the recorded ECG signal with clinical relevance to a computer device, such as either a smartphone 912 or an internet-connected gateway device 914 for subsequent processing and analysis. In this way, the patient or their physician can be provided with potentially valuable diagnostic ECG information during the period that the patient wears the sensor.
As described above, a significant challenge with this approach is to manage the battery life of the wearable sensor without requiring replacement or recharging, both of which reduce user compliance. Each transmission of an ECG from the sensor to a smartphone or local gateway device (using, for example, Bluetooth Low Energy) results in a subsequent reduction in the total charge stored in the sensor battery. Some embodiments of the present disclosure address this issue through the use of a novel hardware and software combination to enable the selective transmission of clinically relevant sections of ECG from a wearable sensor.
In certain embodiments, the wearable sensor incorporates either a software, hardware or hybrid QRS detector that produces a real-time estimate of each R-peak location in the ECG. The R-peak location data is then used to compute an R-R interval time series that is subsequently transmitted to a smartphone or gateway device according to a predefined schedule (for example, once per hour). In addition, a time stamp is also transmitted which stores the onset time for the R-R interval time series relative to the start of the ECG recording. Since the R-R interval time series for a given section of ECG is significantly smaller (in terms of bytes occupied) than the ECG signal itself, it can be transmitted with considerably less impact on battery life.
In some embodiments of a second stage of the system, the R-R interval time series together with the onset time stamp is subsequently transmitted by the smartphone or gateway device to a server. On the server, the R-R interval time series is used to infer a list of the most probable heart rhythms, together with their onset and offset times, during the period represented by the time series data. The list of inferred heart rhythms is then filtered according to specific criteria, such that only rhythms matching the given criteria are retained after filtering. A measure of confidence may also be used to assist in filtering the events in a manner that might improve the Positive Predictivity of detection.
In certain embodiments of a third stage of the system, for each rhythm in the filtered rhythm set, the server transmits to the smartphone or gateway device the onset and offset time for that specific rhythm. In the event that the inferred rhythm duration exceeds a pre-defined maximum duration, the onset and offset times may be adjusted such that the resulting duration is less than the maximum permissible duration. The onset and offset times received by the gateway are then subsequently transmitted to the wearable sensor, which in turn transmits the section of the recorded ECG signal between the onset and offset times back to the gateway. This section of ECG is then transmitted to the server where it can be analyzed and used to provide diagnostic information to the patient or their physician.
In some embodiments, the system fundamentally allows a device worn for up to about: 14, 21, or 30 days or beyond without battery recharging or replacement (both activities that reduce patient compliance and, therefore, diagnostic value) to provide timely communication of asymptomatic arrhythmia events. This development is motivated by technology constraints: in order to enable a small, wearable device that does not require battery change or recharging while providing continuous arrhythmia analysis with high accuracy, it is desirable to limit the complexity of analysis performed on-board. Similarly, streaming of all of the recorded ECG data to an off-board analysis algorithm may not be practical without imposing greater power requirements. This motivates a more creative “triage” approach where selected features of the recorded ECG signal, including but not limited to R-R intervals, are sent for every beat, allowing a customized algorithm to locate a number (for example, 10) of 90-second events to request from the device in full resolution to support comprehensive analysis, for example, a resolution capable of supporting clinical diagnosis.
In other embodiments, the system would provide the ability to detect asymptomatic arrhythmias in a timely manner on a wearable, adhesively affixed device that does not require frequent recharging or replacement. This would be used to enhance the value of some current clinical offerings, which only provide clinical insight after the recording is completed and returned for analysis.
In certain embodiments, the system would allow actionable clinical insight to be derived from data collected on low-cost, easy-to-use consumer wearable devices that are otherwise only focused on fitness and wellness. For example, the technology could be used to create a very effective, low-cost screening tool capable of detecting the presence of Atrial Fibrillation in the at-large population. By using such a tool, not only would patients in need of care be found more easily, but it may be done earlier and more cost effectively, which lead to better outcomes - namely, through reducing stroke risk by identifying AF more quickly.
In particular embodiments, the system may provide the service through a downloadable application that, after receiving customer consent for data access and payment approval, would initiate access and analysis of heart beat data stored from wearable devices, either stored locally in a mobile device or in an online repository. This data pull and analysis would happen through an Algorithm API, and would result in a clinical finding being sent back to the application to be provided to the user. If the data was sufficient to support a “screening oriented” finding, for example, “Likely presence of an irregular rhythm was detected”, the application would direct them to a cardiologist where a more diagnostically focused offering, for example, the ZIO® Service, could be provided to support clinical diagnosis and treatment. In further embodiments, as also described elsewhere in the specification, the system may trigger an alarm if a particular measurement and/or analysis indicates that an alarm is needed.
Further examples of additional scenarios of clinical value may include coupling ambulatory arrhythmia monitoring with a blood-alcohol monitor to study the interaction of AF and lifestyle factors. For example, ambulatory arrhythmia monitoring could be coupled with a blood-glucose monitor to study the impact of Hypoglycemia on arrhythmias. Alternatively, ambulatory arrhythmia monitoring could be coupled with a respiratory rate and/or volume monitor to study the interaction of sleep apnea and breathing disorders. Further, there could be evaluation of the high rates of supraventricular ectopic beats as a potential precursor for AF (for example, 720 SVEs in 24-hour period).
Each of the processes, methods, and algorithms described in the preceding sections may be embodied in, and fully or partially automated by, code modules executed by one or more computer systems or computer processors comprising computer hardware. The code modules may be stored on any type of non-transitory computer-readable medium or computer storage device, such as hard drives, solid state memory, optical disc, and/or the like. The systems and modules may also be transmitted as generated data signals (for example, as part of a carrier wave or other analog or digital propagated signal) on a variety of computer-readable transmission mediums, including wireless-based and wired/cable-based mediums, and may take a variety of forms (for example, as part of a single or multiplexed analog signal, or as multiple discrete digital packets or frames). The processes and algorithms may be implemented partially or wholly in application-specific circuitry. The results of the disclosed processes and process steps may be stored, persistently or otherwise, in any type of non-transitory computer storage such as, for example, volatile or non-volatile storage.
The various features and processes described above may be used independently of one another, or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of this disclosure. In addition, certain method or process blocks may be omitted in some implementations. The methods and processes described herein are also not limited to any particular sequence, and the blocks or states relating thereto can be performed in other sequences that are appropriate. For example, described blocks or states may be performed in an order other than that specifically disclosed, or multiple blocks or states may be combined in a single block or state. The example blocks or states may be performed in serial, in parallel, or in some other manner. Blocks or states may be added to or removed from the disclosed example embodiments. The example systems and components described herein may be configured differently than described. For example, elements may be added to, removed from, or rearranged compared to the disclosed example embodiments.
Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment. The term “including” means “included but not limited to.” The term “or” means “and/or.”
Any process descriptions, elements, or blocks in the flow or block diagrams described herein and/or depicted in the attached figures should be understood as potentially representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process. Alternate implementations are included within the scope of the embodiments described herein in which elements or functions may be deleted, executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those skilled in the art.
All of the methods and processes described above may be at least partially embodied in, and partially or fully automated via, software code modules executed by one or more computers. For example, the methods described herein may be performed by the computing system and/or any other suitable computing device. The methods may be executed on the computing devices in response to execution of software instructions or other executable code read from a tangible computer readable medium. A tangible computer readable medium is a data storage device that can store data that is readable by a computer system. Examples of computer readable mediums include read-only memory, random-access memory, other volatile or non-volatile memory devices, CD-ROMs, magnetic tape, flash drives, and optical data storage devices.
It should be emphasized that many variations and modifications may be made to the above-described embodiments, the elements of which are to be understood as being among other acceptable examples. All such modifications and variations are intended to be included herein within the scope of this disclosure. The foregoing description details certain embodiments. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the systems and methods can be practiced in many ways. For example, a feature of one embodiment may be used with a feature in a different embodiment. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the systems and methods should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the systems and methods with which that terminology is associated.
Various embodiments of a physiological monitoring device, methods, and systems are disclosed herein. These various embodiments may be used alone or in combination, and various changes to individual features of the embodiments may be altered, without departing from the scope of the invention. For example, the order of various method steps may in some instances be changed, and/or one or more optional features may be added to or eliminated from a described device. Therefore, the description of the embodiments provided above should not be interpreted as unduly limiting the scope of the invention as it is set forth in the claims.
Various modifications to the implementations described in this disclosure may be made, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the scope of the disclosure is not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.
Certain features that are described in this specification in the context of separate embodiments also can be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment also can be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, such operations need not be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. Moreover, the separation of various system components in the embodiments described above should not be interpreted as requiring such separation in all embodiments. Additionally, other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.
Claims
1. A wearable device configured to attach to a user, the device comprising:
- a housing enclosing a circuit board;
- a first flexible wing and a second flexible wing, each flexible wing extending from the housing and configured to conform to a surface of the user, each flexible wing having a bottom surface, a top surface, and a thickness between the bottom surface and the top surface, the first flexible wing being positioned substantially opposite the second flexible wing relative to the housing along a longitudinal axis;
- a first electrode coupled to the first flexible wing, the first electrode in electrical communication with the circuit board and being configured to be positioned in conformal contact with the surface of the user to detect the physiological signals;
- a second electrode coupled to the second flexible wing, the second electrode in electrical communication with the circuit board and being configured to be positioned in conformal contact with the surface of the user to detect the physiological signals; and
- an adhesive layer coupled to the bottom surface of the first flexible wing and the bottom surface of the second flexible wing for adhering the wearable device to the user, the adhesive layer having a lower surface, an upper surface interfacing with the bottom surface of the flexible wings, and a thickness between the lower surface and the upper surface,
- wherein the adhesive layer comprises a first portion positioned under the first flexible wing, a second portion positioned under the second flexible wing, and a bridge portion connecting the first portion to the second portion, the upper surface of the bridge portion being non-adhesive and uncoupled to the flexible wing such that the flexible wing may be decoupled from the bridge portion when the adhesive layer is adhered to the surface of the user.
2. The wearable device of claim 1, the bridge portion being narrower than the first portion and the second portion along a direction transverse to the longitudinal axis.
3. The wearable device of claim 1, wherein the bridge portion extends around the housing.
4. The wearable device of claim 3, wherein the adhesive layer comprises a headphone shaped profile or surface area.
5. The wearable device of claim 1, wherein the bridge portion extends beneath the housing.
6. The wearable device of claim 5, wherein the bridge portion bisects the first portion and the second portion.
7. The wearable device of claim 6, wherein the bridge portion forms a bow-tie shape.
8. The wearable device of claim 6, wherein the adhesive layer forms a hinge line across the flexible wings, the flexible wings being configured to adhere to the surface of the user on a first side of the hinge line opposite the housing and to lift off of the surface of the user on a second side of the hinge line opposite the first side.
9. The wearable device of claim 8, wherein a peripheral edge of the adhesive layer is curved where it intersects the hinge line.
10. The wearable device of claim 9, wherein the curved peripheral edge comprises an inflection point, the curvature being convex on the first side of the hinge line and concave on the second side of the hinge line.
11. The wearable device of claim 10, wherein the inflection point is positioned on the hinge line.
12. The wearable device of claim 10, wherein the inflection point is positioned on the first side of the hinge line.
13. The wearable device of claim 10, wherein the inflection point is positioned on the second side of the hinge line.
14. The wearable device of claim 5, wherein the bridge portion extends diagonally beneath the housing from corner of the first portion to a corner of the second portion forming a z-shape or backwards z-shape.
15. The wearable device of claim 14, wherein the adhesive layer forms a hinge line across the flexible wings, the flexible wings being configured to adhere to the surface of the user on a first side of the hinge line opposite the housing and to lift off of the surface of the user on a second side of the hinge line opposite the first side.
16. The wearable device of claim 15, wherein the adhesive layer comprises an edge that extends along a portion of a length of the hinge line.
17. The wearable device of claim 15, wherein the adhesive layer extends across the entire hinge line such that no portion of a peripheral edge extends along a length of the hinge line.
18. The wearable device of claim 1, wherein the adhesive layer is removable.
19. The wearable device of claim 1, wherein:
- the first flexible wing comprises a first layer of a first material having perforations through a thickness of the first layer and a second layer of a second material configured to form a fluid seal from water reaching the adhesive layer from an ambient environment.
20. The wearable device of claim 19, wherein the perforations through the first layer form a latticed structure configured to provide flexible wing anisotropic elastic properties within a plane parallel to the bottom surface and the top surface.
Type: Application
Filed: Jun 6, 2022
Publication Date: Feb 23, 2023
Inventors: Jeffrey Joseph Abercrombie, II (Oakland, CA), Genaro Sebastian Sepulveda (Oakland, CA), Shena Hae Park (San Francisco, CA), Ryan James Wensley (San Francisco, CA), James Kihyun Lee (San Francisco, CA), Thomas Burnell Reeve, III (San Francisco, CA)
Application Number: 17/805,622