Patent Publication Number: US-2021161452-A1

Title: Wireless cardiac sensor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. Non-Provisional Application No. 15/455,987 entitled “Wireless Cardiac Sensor”, filed on Mar. 10, 2017. The entire contents of the above-identified application are hereby incorporated by reference for all purposes. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to medical devices utilizing wireless electronic communications. More specifically, this disclosure relates to wireless mobile cardiac sensors and uses thereof. 
     BACKGROUND 
     As healthcare costs continue to escalate, solutions to reduce the cost and improve the efficacy of diagnostic efforts become increasingly important. In other situations, improving access to medical diagnostic and monitoring capabilities may be desirable. These objectives may be particularly valuable for cardiac care, since cardiac function is vital to human health and well-being, and cardiovascular diseases continue to be the most common cause of death. 
     However, traditional cardiac monitoring and evaluation tools are not well-suited to non-clinical environments. Equipment may be costly and difficult to use for untrained lay users. Cardiac monitoring equipment often involves numerous sensors, requiring specific placement, which may be difficult and time consuming for lay users to apply, and particularly difficult for a user to apply to themselves—thereby preventing or discouraging regular use. Sensor cables can become tangled, pulled and damaged, further frustrating users and reducing equipment reliability. In addition, the majority of all cardiac monitors currently providing continuous monitoring are limited to a short period of time, typically 2 weeks or 30 days. This time limitation is very significant because many cardiac conditions manifest themselves over a long period of months or years, where a short continuous monitoring window will not be useful for the lifetime of the disease. In view of these and other issues, traditional cardiac monitoring equipment may be particularly unsatisfactory for use by patients at their homes, or in other non-clinical environments. 
     SUMMARY 
     A wireless cardiac sensor is provided. In some embodiments, the sensor may be effectively used by lay users in an at home or other non-clinical environment. The sensor includes an audio transducer and ECG electrodes to simultaneously capture heart sound and ECG data. The audio transducer includes a sensor that, together with ECG transducer electrodes, may be positioned on a front surface of a wireless cardiac sensor housing. In some embodiments, ECG electrodes may be arranged on opposite sides of, and preferably adjacent to, the audio transducer sensor. 
     A button may be provided for user interaction with the wireless cardiac sensor. The button may be used for initiating a cardiac monitoring function. The button may be positioned on a back surface of the wireless cardiac sensor, preferably opposite the audio transducer sensor and ECG electrodes, such that the application of pressure on the button may operate to improve contact with the user&#39;s body when in use. Thus, in some applications, the wireless cardiac sensor may be applied to a user&#39;s own body, with one hand. 
     The wireless cardiac sensor may also include a wireless transceiver, for transmitting measured cardiac data to a separate personal electronic device, such as a smartphone, tablet computer, or personal computer. In some embodiments, the wireless cardiac sensor includes a Bluetooth transceiver, for exchanging data with a personal electronic device via a Bluetooth communications link. The personal electronic device includes user interface components, such as a display screen. The personal electronic device display screen may present instructions for proper sensor placement to the user. The personal electronic device may process cardiac data received from the wireless cardiac sensor, and display diagnostic information derived therefore. Data from the wireless cardiac sensor may be stored locally within the personal electronic device, and/or transmitted to remote computing systems for storage and/or analysis. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a front perspective view of a wireless cardiac sensor, in accordance with one embodiment. 
         FIG. 2  is a rear perspective view of a wireless cardiac sensor. 
         FIG. 3  is a schematic block diagram of a wireless cardiac sensor computing environment. 
         FIG. 4  is a schematic block diagram of a wireless cardiac sensor and a personal electronic device, communicating via a wireless communication channel. 
         FIG. 5  is a process for using a wireless cardiac sensor. 
         FIG. 6  is an instructional user interface display on a personal electronic device. 
         FIG. 7  is an instructional user interface display on a personal electronic device. 
         FIG. 8  is an informational user interface display on a personal electronic device. 
         FIG. 9  is a user interface display of acquired sensor data on a personal electronic device. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     While this invention is susceptible to embodiment in many different forms, there are shown in the drawings and will be described in detail herein several specific embodiments, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention to enable any person skilled in the art to make and use the invention, and is not intended to limit the invention to the embodiments illustrated. 
     In accordance with some embodiments, a portable cardiac transducer may be provided that is portable, cost-effective, and simple-to-use for layperson and self-diagnostic applications. 
       FIG. 1  is a front perspective view of a wireless cardiac sensor  100 . Housing  105  encases circuitry described further hereinbelow, and is preferably formed from plastic or other non-conductive material. Housing  105  is generally rectangular cuboid in shape, with rounded edges. Sensor  100  further includes ECG transducer electrodes  110 A and  110 B, positioned on a front side of housing  105 . Electrodes  110 A and  110 B are physically separated from one another to facilitate measurement of electrical signals on a person&#39;s skin resulting from depolarization of the person&#39;s heart muscle during each heartbeat, when appropriately positioned, e.g., against a user&#39;s chest on the user&#39;s left pectoral region. 
     In the embodiment of  FIG. 1 , electrodes  110 A and  110 B are positioned adjacent to, and on opposite sides of, acoustic sensor  112 , which is also positioned on the front side of transducer  100 . When placed against a user&#39;s chest, acoustic sensor  112  may be utilized to detect, record and/or characterize a user&#39;s heart sounds, as conducted acoustically through their chest wall. Acoustic sensor  112  may be a piezoelectric sensor, which along with associated analog-to-digital converters and signal processing components, forms audio transducer  142  ( FIG. 4 ). Collectively, ECG electrodes  110 A and  110 B and acoustic sensor  112  form a sensor package occupying a portion of the front side of sensor housing  105 . 
     By providing an integrated ECG and heart sound sensor within a unitary housing communicating with a wireless communication protocol, cardiac sensor  100  provides significant usability and reliability benefits, particularly for layperson users and/or users of the cardiac sensor in home, field and other non-clinical environments. For example, combining ECG and heart sound sensors in a unitary package allows an individual to easily use the device on themselves, using one hand. Combining ECG and heart sound sensors in one package allows for precise examination of the electrical and mechanical characteristics of the heart. Positioning electrodes  110  and sensor  112  proximate one another, and preferably adjacent, provides a unitary sensor package for a user to position on their chest. The absence of lead wires prevents users from become entangled in wires. The absence of lead wires also improves reliability, as kinked, pulled or tangled cords and strained connectors are common points of failure for conventional cardiac sensors. 
     The shape and design of the sensor housing is optimized to balance multiple factors, including (1) comfort for a user to securely hold against their own chest (fits in the hand); (2) secure fit against a wide variety of patient body types and shapes, male and female, for good contact with electrodes  110 A/B and acoustic sensor  112 ; (3) providing sufficient physical separation of the two ECG electrodes to provide accurate signal quality; and (4) providing an audio transducer sensor of sufficient diameter for optimal detection of heart and lung sound frequencies. The ECG electrodes are of a sufficient size to allow good electrical contact between the patient&#39;s skin and the electrode even if the patient has chest hair or curves of their skin. The ECG electrodes are of a set separation distance to allow for precision placement over the iso-electric lines of the heart. 
       FIG. 2  is a rear perspective view of wireless cardiac transducer  100 . A rear portion of housing  105  includes button  120 . Button  120  may be actuated by a user in order to initiate signal measurement by transducers  140  ( FIG. 4 , described further below). By placing button  120  on a surface of housing  105  that is opposite electrodes  110  and audio sensor  112 , and positioned on that opposing surface at a location that is approximately centered over sensors  110  and  112 , force applied by a user pressing button  120  during a measurement serves to press electrodes  110  and sensor  112  directly against the user&#39;s skin, thereby improving quality of contact with the user&#39;s skin. This configuration may be particularly helpful for applications in which a person is using wireless cardiac sensor  100  on themselves, in a one-handed mode of operation. 
       FIG. 3  is a schematic block diagram of an environment in which wireless cardiac transducer  100  may be beneficially employed. Transducer  100  communications with personal electronic device (“PED”)  400  via wireless communications link  450 , as described further hereinbelow. In some applications, PED  400  may be a computing device having diverse functionality and used for multiple purposes, such as a smartphone, tablet computer, smart watch, laptop computer, desktop computer, voice-controlled home assistant or the like. By integrating functionality between transducer  100  and PED  400 , PED  400  can be used to implement various elements of functionality that are beneficial to use of transducer  100 , thereby reducing the cost and complexity of transducer  100 . For example, in some embodiments, PED  400  may be a smartphone having a graphical display, touchscreen and application software enabling exchange of data and control signaling with transducer  100 . 
     PED  400  communicates with other systems and devices via wide area network (WAN)  300 , which may include the Internet. In some embodiments, server  310  may be provided to implement services associated with transducer  100 , such as data storage, data analysis, data publication, as well as web applications and/or application programming interfaces for same. Health care provider devices  320  are electronic systems and devices used by health care service providers, in order to exchange information with server  310  and/or PED  400 , as described further hereinbelow. Devices  320  may include smartphones, tablet computers, personal computers, or healthcare service provider computing systems or equipment. 
       FIG. 4  is a detailed schematic block diagram of cardiac sensor  100 , as it interacts with PED  400 . Cardiac sensor  100  includes microprocessor  130  and digital memory  132 . Battery  134  is a rechargeable battery serving to power wireless transducer  100  during operation. In some embodiments, it may be desirable for battery  134  to incorporate wireless charging circuitry, thereby enabling further minimization or avoidance of ports and other apertures within the cardiac sensor housing. 
     Transducer package  140  include audio transducer  142 . Audio transducer  142  includes piezoelectric sensor  112 ; an analog-to-digital converter to digitize audio signals detected by sensor  112 ; as well as signal processing circuitry to filter and condition detected signals. Audio signal processing circuitry may be implemented in the analog domain (i.e. prior to digitization), in the digital domain (i.e. by microprocessor  130  and/or a dedicated digital signal processing integrated circuit) or both. 
     Transducer package  140  also includes ECG transducer  144 . ECG transducer  144  includes ECG electrodes  110 A and  110 B; an analog-to-digital converter to digitize voltage differentials measured by electrodes  110 A and  110 B; as well as signal processing circuitry to filter and conditions detected signals. ECG signal processing circuitry may be implemented in the analog domain (i.e. prior to digitization), in the digital domain (i.e. by microprocessor  130  and/or a dedicated digital signal processing integrated circuit) or both. 
     Cardiac sensor wireless transceiver  136  is preferably a Bluetooth transceiver, enabling wireless digital communications with other Bluetooth-enabled devices, such as PED  400 , via wireless communication link  450 . In some embodiments, PED  400  may be a standard, commodity mobile wireless computing device, such as a smartphone (e.g. Apple iPhone™), tablet computer (e.g. Apple iPad™), or laptop computer. In other embodiments, PED  400  may less preferably be a dedicated computing device, such as a central sensor monitoring station with embedded software. PED  400  includes wireless (e.g. Bluetooth) transceiver  402 , microprocessor  404 , user interface components  406  (such as a touch-sensitive display screen, or combinations of graphical display, keyboard, mouse, touchpad or the like), digital memory  408  for data storage, and battery  410  for cordless operation. Various wireless communication protocols may be utilized to convey data between cardiac sensor  100  and PED  400 , including, without limitation, those described in applicant&#39;s co-pending U.S. patent application Ser. No. 15/384,506, filed on Dec. 20, 2016, the contents of which are hereby incorporated by reference in their entirety. 
     By providing a cardiac sensor  100  which is compact in size, while leveraging a user&#39;s existing personal electronic device  400  for functions such as data storage, analysis, transmission and user interaction, cardiac sensor  100  may be relatively inexpensive as compared to alternative solutions. 
       FIG. 5  illustrates an exemplary process for using cardiac sensor  100 . In step S 500 , a user initiates use of a software application installed on PED  400 . For example, in an embodiment in which PED  400  is a smartphone, a smartphone app may be downloaded and installed on PED  400 . The app may subsequently be executed by processor  404  to control operation of PED  400 . When launched, the app may provide guidance and instructions to the user via UI  406 . For example, the app may provide visual displays on a display screen to illustrate proper placement of cardiac sensor  100  on the user&#39;s body. 
     In step S 510 , a user places cardiac sensor  100  into contact with their chest, preferably over their left pectoral area and with guidance displayed on PED UI  406 . Electrodes  110 A and  110 B contact the user&#39;s chest, enabling ECG transducer  144  to measure electrical changes on the skin occurring as a result of the heart muscle&#39;s electrophysiologic pattern of depolarization during each heartbeat. Simultaneously, piezoelectric sensor  112  makes physical contact with the user&#39;s chest to detect heart sounds conducted through the user&#39;s chest wall to audio transducer  142 . 
     In step S 520 , the user presses button  120  to initiate cardiac monitoring. Specifically, depression of button  120  initiates simultaneous recording of ECG and heart sound data by transducer package  140 . With a cardiac sensor embodiment such as that of  FIGS. 1 and 2 , a user may readily hold sensor  100  against their own chest with one hand, while utilizing one finger to press button  120 . 
     In step S 530 , cardiac sensor  100  captures cardiac data generated by transducers  140  and transmits that data to PED  400 . In the course of doing so, electrical signals generated by transducers  142  and  144  are digitized using analog-to-digital converters. Various filters and other signal processing operations may be performed on the sensed ECG and heart sound signals, either locally within cardiac sensor  100 , remotely by PED  400 , or elsewhere. Data may be stored for a period of time locally within cardiac sensor memory  132 , before, during and/or after transmission to PED  400 . Preferably, ECG and heart sound data is streamed in near-real time from sensor  100  to PED  400  via wireless communication link  450 . Such cardiac data is then stored locally within PED  400  by digital memory  408 . 
     In step S 540 , cardiac data received by PED  400  may be published to other stakeholders in a user&#39;s care. For example, in some embodiments, PED  400  (under control of the application initiated in step S 500 ) may transmit recorded cardiac data to a centralized server  310  via WAN  300 . Server  310  may then make the recorded cardiac data available to other services, such as health care provider computing devices  320  accessing server  310  via a web application or application programming interface. In such a use case, a patient using cardiac monitor  100  at home or in another non-clinical environment, may make data from cardiac sensor  100  available to doctors or other health care professionals in remote locations for expert diagnostic purposes. 
     In some embodiments, cardiac data may be streamed from sensor  100  to PED  400  to server  310 , such that the data may be made available to third parties in near-real time. In some embodiments, data from cardiac monitoring sessions may be stored over time within server  310 , providing a repository of historical data for subsequent analysis by, e.g., health care professionals. 
     In some embodiments, PED  400  may also retain a repository of historical cardiac monitoring data, with local software applications operating on PED  400  providing tools for analyzing such data and providing diagnostic results based thereon, delivered via displays on UI  406 . 
     In some embodiments, the PED  400  may provide feedback to the user on the quality of the ECG and PCG (phonocardiogram) signals obtained, preferably including a voice-based audio feedback system to communicate this information to the user during the process of signal acquisition. In particular, PED  400  may execute a local application on microprocessor  404 , to assess sensor data received via transceiver  402  and, based on that assessment, workflow logic and/or other logic implemented by the local application, provide feedback to the user via user interface  406 , preferably including audio instructions and feedback via an audio loudspeaker within UI  406 . For example, upon initiating a cardiac monitoring session, PED  400  may render user interface display  600  ( FIG. 6 ) on a display screen to prompt the user regarding positioning of sensor  100 , while simultaneously playing audio instructions as well. After the user presses a button to start measurement, PED  400  may render user interface display  700  ( FIG. 7 ) on the PED display screen to instruct the user to remain still during the measurement. The audio and/or visual feedback will alert the user when a data capture is complete or when data quality is poor. 
     In some embodiments, PED  400  will alert the user when a data capture is reviewed by a physician or clinician and/or is sent to the physician or clinician (such as via transmission from PED  400  to healthcare provider device  320  via wide area network  300 ). In particular, PED  400  may render user interface  800  ( FIG. 8 ) to confirm transmission of sensor data to a health care provider. 
     PED  400  may also operate to display data acquired via sensor  100  for user review.  FIG. 9  illustrates a user interface display  900  that may be rendered on a display screen. Display  900  includes two continuous waveforms  910  and  915  of the ECG and PCG data, allowing a user to compare differences or similarities between the data. Display  900  includes other diagnostic as well, derived from waveforms  910  and  915 , such as heart rate output  920 . 
     The foregoing description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention disclosed herein. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. All references cited herein are expressly incorporated by reference.