Patent Publication Number: US-2022219001-A1

Title: System and method for data exchange and charging

Description:
FIELD 
     This application relates in general to cardiac monitoring and, in particular, to a system and method for data exchange and charging. 
     BACKGROUND 
     The heart emits electrical signals as a by-product of the propagation of the action potentials that trigger depolarization of heart fibers. An electrocardiogram (ECG) measures and records such electrical potentials to visually depict the electrical activity of the heart over time. Conventionally, dermal ECG electrodes positioned on and insertable cardiac monitors (ICMs) implanted in a patient are utilized to sense cardiac electrical activity. The sensed cardiac electrical activity is represented by PQRSTU waveforms that can be interpreted post-ECG recordation to derive heart rate and physiology. The P-wave represents atrial electrical activity. The QRSTU components represent ventricular electrical activity. 
     An ECG is a tool used by physicians to diagnose heart problems and other potential health concerns. An ECG is a snapshot of heart function, typically recorded over 12 seconds, that can help diagnose rate and regularity of heartbeats, effect of drugs or cardiac devices, including pacemakers and implantable cardioverter-defibrillators (ICDs), and whether a patient has heart disease. ECGs are used in-clinic during appointments, and, as a result, are limited to recording only those heart-related aspects present at the time of recording. Sporadic conditions that may not show up during a spot ECG recording require other means to diagnose them. These disorders include fainting or syncope; rhythm disorders, such as tachyarrhythmias and bradyarrhythmias; apneic episodes; and other cardiac and related disorders. Thus, an ECG only provides a partial picture and can be insufficient for complete patient diagnosis of many cardiac disorders. 
     Long term monitoring of a patient via a dermal cardiac device or ICM can provide a larger picture of a patient&#39;s cardiac activity, such as over a time span of 7 days or more, which can be helpful to identify conditions and disorders that are not generally viewed during a spot ECG recording. However, the data recorded by the dermal cardiac device or ICM is generally accessed by a medical professional after a scheduled data transmission which can be hours or days later. 
     Typically, data is downloaded from the device at preset intervals. To download the data, a wand or other device is placed over the patient&#39;s cardiac device to access the stored data, such as via a wireless connection. The accessed data can then be stored and processed. However, since the cardiac data is collected at a predetermined time such data is generally not useful to identify or diagnose a condition or disorder of the patient, unless the patient is in the office or medical facility. 
     Remote real-time views of the cardiac data can be useful in treating a patient, such as when a patient experiences a cardiac event. For example, after a patient experiences a cardiac event, such as palpitations, the patient can contact his physician or an alert can be delivered to the physician that a cardiac event has occurred. The physician can then review the patient&#39;s cardiac activity in real-time to determine whether the patient needs additional care or should go to the hospital. 
     While some conventional cardiac monitors, both dermal and ICMs, include wireless data transmission, such devices do not allow for real-time streaming of cardiac data from the device to a remote computer. As described above, the cardiac data collected by the cardiac monitor is generally retrieved via a wand on a tablet or other computer. Each time the computer communicates with the server. 
     Therefore, a need remains for remote real-time streaming of cardiac data and designated pathways for communication of ECG and parameter data to and from the implantable medical device. 
     SUMMARY 
     Physiological monitoring can be provided through a wearable monitor that includes two components, a flexible extended wear electrode patch and a removable reusable monitor recorder. The wearable monitor sits centrally (in the midline) on the patient&#39;s chest along the sternum oriented top-to-bottom. The placement of the wearable monitor in a location at the sternal midline (or immediately to either side of the sternum), with its unique narrow “hourglass”-like shape, benefits long-term extended wear by removing the requirement that ECG electrodes be continually placed in the same spots on the skin throughout the monitoring period. Instead, the patient is free to place an electrode patch anywhere within the general region of the sternum. In addition, power is provided through a battery provided on the electrode patch, which avoids having to either periodically open the housing of the monitor recorder for the battery replacement, which also creates the potential for moisture intrusion and human error, or to recharge the battery, which can potentially take the monitor recorder off line for hours at a time. In addition, the electrode patch is intended to be disposable, while the monitor recorder is a reusable component. Thus, each time that the electrode patch is replaced, a fresh battery is provided for the use of the monitor recorder. 
     Further, long-term electrocardiographic and physiological monitoring over a period lasting up to several years in duration can be provided through a continuously-recording subcutaneous insertable cardiac monitor (ICM), such as one described in commonly-owned U.S. patent application Ser. No. 15/832,385, filed Dec. 5, 2017, pending, the disclosure of which is incorporated by reference. The sensing circuitry and the physical layout of the electrodes are specifically optimized to capture electrical signals from the propagation of low amplitude, relatively low frequency content cardiac action potentials, particularly the P-waves that are generated during atrial activation. In general, the ICM is intended to be implanted centrally and positioned axially and slightly to either the left or right of the sternal midline in the parasternal region of the chest. 
     In one embodiment, an insertable cardiac monitor (ICM) for use in performing long term electrocardiographic (ECG) monitoring is provided. The monitor includes; an implantable housing included of a biocompatible material that is suitable for implantation within a living body; at least one pair of ECG sensing electrodes provided on a ventral surface and on opposite ends of the implantable housing operatively placed to facilitate sensing in closest proximity to the low amplitude, low frequency content cardiac action potentials that are generated during atrial activation; and electronic circuitry provided within the housing assembly. The electronic circuitry includes an ECG front end circuit interfaced to a low-power microcontroller and configured to capture the cardiac action potentials sensed by the pair of ECG sensing electrodes which are output as ECG signals; the low power microcontroller operable to execute under modular micro program control as specified in firmware, the microcontroller operable to read samples of the ECG signals, buffer the samples of the ECG signals, compress the buffered samples of the ECG signals, buffer the compressed samples of the ECG signals, and write the buffered samples into a non-volatile flash memory; and the non-volatile memory electrically interfaced with the microcontroller and operable to store the written samples of the ECG signals. 
     Remote real-time streaming of ECG and other physiological data can occur based on a continuous communication connection between a cardiac monitor and a cloud server or between a home station and the cloud server. The cardiac monitor encrypts and transmits the data either directly to the cloud server or via a puck to the home station. Once received by the home station, the encrypted data is then transmitted to the cloud server, which then transmits the data to a remote physician via a computing device. Due to the continuous connection, the data transfer is in real-time, while the encryption provides a secure communication of the data. 
     An embodiment provides a system and method for remote ECG data streaming in real-time. ECG data is encrypted on a physiological monitor placed on a patient via a near-field communication chip on the physiological monitor. A continuous connection is established between the physiological monitor and a cloud-based server via a wireless transceiver on the physiological monitor. The encrypted ECG data is transmitted from the physiological monitor to the cloud-based server. The ECG data is then transmitted from the cloud-based server to a device associated with a medical professional in real-time. 
     Data can be communicated between an IMD, bedside monitor, and backend for data analysis, device updates, and charging. For example, the ICM can provide ECG data, logs, and component status to the backend via the bedside monitor, while the backend can provide ICM component firmware updates and initial charge parameters to the IMD via the bedside monitor. Additionally, the bedside monitor can communicate data directly to the backend without input from the 1 MB by providing logs for components of the bedside monitor and a status of the components. Conversely, the backend can provide firmware updates to the components of the bedside monitor. 
     The IMD can be charged using a puck that can be attached to or separate from the bedside monitor. Charging can be initialized by the 1 MB by providing charge parameters and updates to the charge parameters. During charging, data can also be communicated between the 1 MB and the bedside monitor via the charge waveforms, using Bluetooth, or via blanking, which interleaves charging and data transfer. 
     In a recovery mode, the bedside monitor can provide the 1 MB with debug commands, while the IMD provides error logs and bug responses to the bedside monitor. Also, upon starting up the bedside monitor, WiFi provisioning can be run to allow the user to set up the bedside monitor by connecting the bedside monitor to a user application via Bluetooth and receiving available networks for WiFi. Finally, the IDM can provide ECG data to the backend via a phone application, instead of via the bedside monitor. 
     An embodiment provides a method for data exchange and charging. An implantable medical device is monitored and charging of the implantable medical device is initiated by providing charge parameters to a bedside monitor. Communication is initiated between a puck associated with the bedside monitor and implantable medical device. The implantable medical device is charged using the charge parameters. Simultaneously with the charging, transfer of data between the implantable medical device and the bedside monitor is initiated. 
     Still other embodiments will become readily apparent to those skilled in the art from the following detailed description, wherein are described embodiments by way of illustrating the best mode contemplated. As will be realized, other and different embodiments are possible and the embodiments&#39; several details are capable of modifications in various obvious respects, all without departing from their spirit and the scope. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 2  are diagrams showing, by way of examples, an extended wear electrocardiography and physiological sensor monitor, including a monitor recorder in accordance with one embodiment, respectively fitted to the sternal region of a female patient and a male patient. 
         FIG. 3  is a perspective view showing an extended wear electrode patch with a monitor recorder in accordance with one embodiment inserted. 
         FIG. 4  is a perspective view showing the monitor recorder of  FIG. 3 . 
         FIG. 5  is a perspective view showing the extended wear electrode patch of  FIG. 3  without a monitor recorder inserted. 
         FIG. 6  is a bottom plan view of the monitor recorder of  FIG. 3 . 
         FIG. 7  is a top view showing the flexible circuit of the extended wear electrode patch of  FIG. 3  when mounted above the flexible backing. 
         FIG. 8  is a functional block diagram showing the component architecture of the circuitry of the monitor recorder of  FIG. 3 . 
         FIG. 9  is a functional block diagram showing the circuitry of the extended wear electrode patch of  FIG. 3 . 
         FIG. 10  is a flow diagram showing a monitor recorder-implemented method for monitoring ECG data for use in the monitor recorder of  FIG. 3 . 
         FIG. 11  is a graph showing, by way of example, a typical ECG waveform. 
         FIG. 12  is a diagram showing, by way of example, a subcutaneous P-wave centric insertable cardiac monitor (ICM) for long term electrocardiographic monitoring in accordance with one embodiment. 
         FIGS. 12 and 13  are respectively top and bottom perspective views showing the ICM of  FIG. 12 . 
         FIG. 14  is a bottom perspective view showing the ICM of  FIG. 12  in accordance with a further embodiment. 
         FIGS. 15 and 16  are respectively top and bottom perspective views showing an ICM in accordance with a still further embodiment. 
         FIG. 17  is a plan view showing further electrode configurations. 
         FIG. 18  is a functional block diagram showing the P-wave focused component architecture of the circuitry of the ICM of  FIG. 12 . 
         FIG. 19  is a functional block diagram showing a system for wirelessly interfacing with an ICM in accordance with one embodiment. 
         FIG. 20  is a functional block diagram showing a system  300  for obtaining ECG data from a cardiac monitor, in accordance with one embodiment. 
         FIG. 21  is a functional block diagram showing a system  320  for real-time remote streaming of ECG data, in accordance with one embodiment. 
         FIG. 22  is a block diagram showing, by way of example, ICM initiated data flow paths. 
         FIG. 23  is a block diagram showing, by way of example, a bedside monitor-initiated data flow. 
         FIG. 24  is a block diagram showing, by way of example, an ICM initiated charging data flow. 
         FIG. 25  is a block diagram showing, by way of example, a recovery mode data flow. 
         FIG. 26  is a block diagram showing, by way of example, a bedside monitor WiFi provisioning data flow, which is initiated by a user. 
         FIG. 27  is a block diagram showing, by way of example, an ICM initiated data flow. 
     
    
    
     DETAILED DESCRIPTION 
     Related Applications 
     This provisional patent application is related to in commonly-assigned U.S. Pat. No. 9,545,204, issued Jan. 17, 2017 to Bishay et al.; U.S. Pat. No. 9,730,593, issued Aug. 15, 2017 to Felix et al.; U.S. Pat. No. 9,717,432, issued Aug. 1, 2017 to Felix et al.; U.S. Pat. No. 9,775,536, issued Oct. 3, 2017 to Felix et al.; U.S. Pat. No. 9,433,380, issued Sep. 6, 2016 to Bishay et al.; U.S. Pat. No. 9,655,538, issued May 23, 2017 to Felix et al.; U.S. Pat. No. 9,364,155, issued Jun. 14, 2016 to Bardy et al.; U.S. Pat. No. 9,737,224, issued Aug. 22, 2017 to Bardy et al.; U.S. Pat. No. 9,433,367, issued Sep. 6, 2016 to Felix et al.; U.S. Pat. No. 9,700,227, issued Jul. 11, 2017 to Bishay et al.; U.S. Pat. No. 9,717,433, issued Aug. 1, 2017 to Felix et al.; U.S. Pat. No. 9,615,763, issued Apr. 11, 2017 to Felix et al.; U.S. Pat. No. 9,642,537, issued May 9, 2017 to Felix et al.; U.S. Pat. No. 9,408,545, issued Aug. 9, 2016 to Felix et al.; U.S. Pat. No. 9,655,537, issued May 23, 2017 to Bardy et al.; U.S. Pat. No. 10,165,946, issued Jan. 1, 2019 to Bardy et al.; U.S. Patent Application Publication No. 2017/0258358, published Sep. 14, 2017 to Bishay et al.; U.S. patent application Ser. No. 14/656,615, entitled: “Contact-Activated Extended Wear Electrocardiography And Physiological Sensor Monitor Recorder,” filed Mar. 12, 2015, pending; U.S. Pat. No. 9,619,660, issued Apr. 11, 2017 to Felix et al.; U.S. Patent Application Publication No. 2019/0090769, published Mar. 28, 2019 to Boleyn et al.; U.S. Pat. No. 9,408,551, issued Aug. 9, 2016 to Bardy et al.; U.S. Patent Application Publication No. 2019/0069800, published Mar. 7, 2019 to Bardy et al.; U.S. Patent Application Publication No. 2019/0069798, published Mar. 7, 2019 to Bardy et al.; U.S. Patent Application Publication No. 2019/0117099, published Apr. 25, 2019 to Bardy et al.; U.S. Patent Application Publication No. 2019/0099105, published Apr. 4, 2019 to Felix et al.; U.S. Patent Application Publication No. 2019/0150776, published May 23, 2019 to Bardy et al.; U.S. Pat. No. 10,251,576, issued Apr. 9, 2019 to Bardy et al.; U.S. Pat. No. 9,345,414, issued May 24, 2016 to Bardy et al.; U.S. Patent Application Publication No. 2019/0069794, published Mar. 7, 2019 to Bardy et al.; U.S. Pat. No. 9,504,423, issued Nov. 29, 2016 to Bardy et al.; U.S. Patent Application Publication No. 2019/0167139, published Jun. 6, 2019 to Bardy et al.; U.S. Design Pat. No. D717955, issued Nov. 18, 2014 to Bishay et al.; U.S. Design Pat. No. D744659, issued Dec. 1, 2015 to Bishay et al.; U.S. Design Pat. No. D838370, issued Jan. 15, 2019 to Bardy et al.; U.S. Design Pat. No. D801528, issued Oct. 31, 2017 to Bardy et al.; U.S. Design Patent No. D766447, issued Sep. 13, 2016 to Bishay et al.; U.S. Design Pat. No. D793566, issued Aug. 1, 2017 to Bishay et al.; U.S. Design Pat. No. D831833, issued Oct. 23, 2018 to Bishay et al.; U.S. Design patent application Ser. No. 29/612,334, entitled: “Extended Wear Electrode Patch,” filed Jul. 31, 2017, pending, and Provisional Patent Application No. 62/870,506, entitled: “Subcutaneous P-Wave Centric Cardiac Monitor With Energy Harvesting Capabilities,” filed Jul. 3, 2019, pending, the disclosures of which are incorporated by reference. 
     Overview 
     Physiological monitoring can be provided through a wearable monitor that includes two components, a flexible extended wear electrode patch and a removable reusable monitor recorder.  FIGS. 1 and 2  are diagrams showing, by way of examples, an extended wear electrocardiography and physiological sensor monitor  12 , including a monitor recorder  14  in accordance with one embodiment, respectively fitted to the sternal region of a female patient  10  and a male patient  11 . The wearable monitor  12  sits centrally (in the midline) on the patient&#39;s chest along the sternum  13  oriented top-to-bottom with the monitor recorder  14  preferably situated towards the patient&#39;s head. In a further embodiment, the orientation of the wearable monitor  12  can be corrected post-monitoring, as further described infra. The electrode patch  15  is shaped to fit comfortably and conformal to the contours of the patient&#39;s chest approximately centered on the sternal midline  16  (or immediately to either side of the sternum  13 ). The distal end of the electrode patch  15  extends towards the Xiphoid process and, depending upon the patient&#39;s build, may straddle the region over the Xiphoid process. The proximal end of the electrode patch  15 , located under the monitor recorder  14 , is below the manubrium and, depending upon patient&#39;s build, may straddle the region over the manubrium. 
     The placement of the wearable monitor  12  in a location at the sternal midline  16  (or immediately to either side of the sternum  13 ) significantly improves the ability of the wearable monitor  12  to cutaneously sense cardiac electric signals, particularly the P-wave (or atrial activity) and, to a lesser extent, the QRS interval signals in the ECG waveforms that indicate ventricular activity. The sternum  13  overlies the right atrium of the heart and the placement of the wearable monitor  12  in the region of the sternal midline  13  puts the ECG electrodes of the electrode patch  15  in a location better adapted to sensing and recording P-wave signals than other placement locations, say, the upper left pectoral region. In addition, placing the lower or inferior pole (ECG electrode) of the electrode patch  15  over (or near) the Xiphoid process facilitates sensing of right ventricular activity and provides superior recordation of the QRS interval. 
     During use, the electrode patch  15  is first adhesed to the skin along the sternal midline  16  (or immediately to either side of the sternum  13 ). A monitor recorder  14  is then snapped into place on the electrode patch  15  to initiate ECG monitoring.  FIG. 3  is a perspective view showing an extended wear electrode patch  15  with a monitor recorder  14  in accordance with one embodiment inserted. The body of the electrode patch  15  is preferably constructed using a flexible backing  20  formed as an elongated strip  21  of wrap knit or similar stretchable material with a narrow longitudinal mid-section  23  evenly tapering inward from both sides. A pair of cut-outs  22  between the distal and proximal ends of the electrode patch  15  create a narrow longitudinal midsection  23  or “isthmus” and defines an elongated “hourglass”-like shape, when viewed from above. 
     The electrode patch  15  incorporates features that significantly improve wearability, performance, and patient comfort throughout an extended monitoring period. During wear, the electrode patch  15  is susceptible to pushing, pulling, and torqueing movements, including compressional and torsional forces when the patient bends forward, and tensile and torsional forces when the patient leans backwards. To counter these stress forces, the electrode patch  15  incorporates strain and crimp reliefs, such as described in commonly-assigned U.S. patent, entitled “Extended Wear Electrocardiography Patch,” U.S. Pat. No. 9,545,204, issued on Jan. 17, 2017, the disclosure of which is incorporated by reference. In addition, the cut-outs  22  and longitudinal midsection  23  help minimize interference with and discomfort to breast tissue, particularly in women (and gynecomastic men). The cut-outs  22  and longitudinal midsection  23  further allow better conformity of the electrode patch  15  to sternal bowing and to the narrow isthmus of flat skin that can occur along the bottom of the intermammary cleft between the breasts, especially in buxom women. The cut-outs  22  and longitudinal midsection  23  help the electrode patch  15  fit nicely between a pair of female breasts in the intermammary cleft. Still other shapes, cut-outs and conformities to the electrode patch  15  are possible. 
     The monitor recorder  14  removably and reusably snaps into an electrically non-conductive receptacle  25  during use. The monitor recorder  14  contains electronic circuitry for recording and storing the patient&#39;s electrocardiography as sensed via a pair of ECG electrodes provided on the electrode patch  15 , as further described infra beginning with reference to  FIG. 8 . The non-conductive receptacle  25  is provided on the top surface of the flexible backing  20  with a retention catch  26  and tension clip  27  molded into the non-conductive receptacle  25  to conformably receive and securely hold the monitor recorder  14  in place. 
     The monitor recorder  14  includes a sealed housing that snaps into place in the non-conductive receptacle  25 .  FIG. 4  is a perspective view showing the monitor recorder  14  of  FIG. 3 . The sealed housing  50  of the monitor recorder  14  intentionally has a rounded isosceles trapezoidal-like shape  52 , when viewed from above, such as described in commonly-assigned U.S. Design patent, entitled “Electrocardiography Monitor,” No. D717955, issued on Nov. 18, 2014, the disclosure of which is incorporated by reference. The edges  51  along the top and bottom surfaces are rounded for patient comfort. The sealed housing  50  is approximately 47 mm long, 23 mm wide at the widest point, and 7 mm high, excluding a patient-operable tactile-feedback button  55 . The sealed housing  50  can be molded out of polycarbonate, ABS, or an alloy of those two materials. The button  55  is waterproof and the button&#39;s top outer surface is molded silicon rubber or similar soft pliable material. A retention detent  53  and tension detent  54  are molded along the edges of the top surface of the housing  50  to respectively engage the retention catch  26  and the tension clip  27  molded into non-conductive receptacle  25 . Other shapes, features, and conformities of the sealed housing  50  are possible. 
     The electrode patch  15  is intended to be disposable. The monitor recorder  14 , however, is reusable and can be transferred to successive electrode patches  15  to ensure continuity of monitoring. The placement of the wearable monitor  12  in a location at the sternal midline  16  (or immediately to either side of the sternum  13 ) benefits long-term extended wear by removing the requirement that ECG electrodes be continually placed in the same spots on the skin throughout the monitoring period. Instead, the patient is free to place an electrode patch  15  anywhere within the general region of the sternum  13 . 
     As a result, at any point during ECG monitoring, the patient&#39;s skin is able to recover from the wearing of an electrode patch  15 , which increases patient comfort and satisfaction, while the monitor recorder  14  ensures ECG monitoring continuity with minimal effort. A monitor recorder  14  is merely unsnapped from a worn out electrode patch  15 , the worn out electrode patch  15  is removed from the skin, a new electrode patch  15  is adhered to the skin, possibly in a new spot immediately adjacent to the earlier location, and the same monitor recorder  14  is snapped into the new electrode patch  15  to reinitiate and continue the ECG monitoring. 
     During use, the electrode patch  15  is first adhered to the skin in the sternal region.  FIG. 5  is a perspective view showing the extended wear electrode patch  15  of  FIG. 3  without a monitor recorder  14  inserted. A flexible circuit  32  is adhered to each end of the flexible backing  20 . A distal circuit trace  33  and a proximal circuit trace (not shown) electrically couple ECG electrodes (not shown) to a pair of electrical pads  34 . The electrical pads  34  are provided within a moisture-resistant seal  35  formed on the bottom surface of the non-conductive receptacle  25 . When the monitor recorder  14  is securely received into the non-conductive receptacle  25 , that is, snapped into place, the electrical pads  34  interface to electrical contacts (not shown) protruding from the bottom surface of the monitor recorder  14 , and the moisture-resistant seal  35  enables the monitor recorder  14  to be worn at all times, even during bathing or other activities that could expose the monitor recorder  14  to moisture. 
     In addition, a battery compartment  36  is formed on the bottom surface of the non-conductive receptacle  25 , and a pair of battery leads (not shown) electrically interface the battery to another pair of the electrical pads  34 . The battery contained within the battery compartment  35  can be replaceable, rechargeable or disposable. 
     The monitor recorder  14  draws power externally from the battery provided in the non-conductive receptacle  25 , thereby uniquely obviating the need for the monitor recorder  14  to carry a dedicated power source.  FIG. 6  is a bottom plan view of the monitor recorder  14  of  FIG. 3 . A cavity  58  is formed on the bottom surface of the sealed housing  50  to accommodate the upward projection of the battery compartment  36  from the bottom surface of the non-conductive receptacle  25 , when the monitor recorder  14  is secured in place on the non-conductive receptacle  25 . A set of electrical contacts  56  protrude from the bottom surface of the sealed housing  50  and are arranged in alignment with the electrical pads  34  provided on the bottom surface of the non-conductive receptacle  25  to establish electrical connections between the electrode patch  15  and the monitor recorder  14 . In addition, a seal coupling  57  circumferentially surrounds the set of electrical contacts  56  and securely mates with the moisture-resistant seal  35  formed on the bottom surface of the non-conductive receptacle  25 . 
     The placement of the flexible backing  20  on the sternal midline  16  (or immediately to either side of the sternum  13 ) also helps to minimize the side-to-side movement of the wearable monitor  12  in the left- and right-handed directions during wear. To counter the dislodgment of the flexible backing  20  due to compressional and torsional forces, a layer of non-irritating adhesive, such as hydrocolloid, is provided at least partially on the underside, or contact, surface of the flexible backing  20 , but only on the distal end  30  and the proximal end  31 . As a result, the underside, or contact surface of the longitudinal midsection  23  does not have an adhesive layer and remains free to move relative to the skin. Thus, the longitudinal midsection  23  forms a crimp relief that respectively facilitates compression and twisting of the flexible backing  20  in response to compressional and torsional forces. Other forms of flexible backing crimp reliefs are possible. 
     Unlike the flexible backing  20 , the flexible circuit  32  is only able to bend and cannot stretch in a planar direction. The flexible circuit  32  can be provided either above or below the flexible backing  20 .  FIG. 7  is a top view showing the flexible circuit  32  of the extended wear electrode patch  15  of  FIG. 3  when mounted above the flexible backing  20 . A distal ECG electrode  38  and proximal ECG electrode  39  are respectively coupled to the distal and proximal ends of the flexible circuit  32 . A strain relief  40  is defined in the flexible circuit  32  at a location that is partially underneath the battery compartment  36  when the flexible circuit  32  is affixed to the flexible backing  20 . The strain relief  40  is laterally extendable to counter dislodgment of the ECG electrodes  38 ,  39  due to tensile and torsional forces. A pair of strain relief cutouts  41  partially extend transversely from each opposite side of the flexible circuit  32  and continue longitudinally towards each other to define in ‘S’-shaped pattern, when viewed from above. The strain relief respectively facilitates longitudinal extension and twisting of the flexible circuit  32  in response to tensile and torsional forces. Other forms of circuit board strain relief are possible. 
     ECG monitoring and other functions performed by the monitor recorder  14  are provided through a micro controlled architecture.  FIG. 8  is a functional block diagram showing the component architecture of the circuitry  60  of the monitor recorder  14  of  FIG. 3 . The circuitry  60  is externally powered through a battery provided in the non-conductive receptacle  25  (shown in  FIG. 5 ). Both power and raw ECG signals, which originate in the pair of ECG electrodes  38 ,  39  (shown in  FIG. 7 ) on the distal and proximal ends of the electrode patch  15 , are received through an external connector  65  that mates with a corresponding physical connector on the electrode patch  15 . The external connector  65  includes the set of electrical contacts  56  that protrude from the bottom surface of the sealed housing  50  and which physically and electrically interface with the set of pads  34  provided on the bottom surface of the non-conductive receptacle  25 . The external connector includes electrical contacts  56  for data download, microcontroller communications, power, analog inputs, and a peripheral expansion port. The arrangement of the pins on the electrical connector  65  of the monitor recorder  14  and the device into which the monitor recorder  14  is attached, whether an electrode patch  15  or download station (not shown), follow the same electrical pin assignment convention to facilitate interoperability. The external connector  65  also serves as a physical interface to a download station that permits the retrieval of stored ECG monitoring data, communication with the monitor recorder  14 , and performance of other functions. Operation of the circuitry  60  of the monitor recorder  14  is managed by a microcontroller  61 . The micro-controller  61  includes a program memory unit containing internal flash memory that is readable and writeable. The internal flash memory can also be programmed externally. The micro-controller  61  draws power externally from the battery provided on the electrode patch  15  via a pair of the electrical contacts  56 . The microcontroller  61  connects to the ECG front end circuit  63  that measures raw cutaneous electrical signals and generates an analog ECG signal representative of the electrical activity of the patient&#39;s heart over time. 
     The circuitry  60  of the monitor recorder  14  also includes a flash memory  62 , which the micro-controller  61  uses for storing ECG monitoring data and other physiology and information. The flash memory  62  also draws power externally from the battery provided on the electrode patch  15  via a pair of the electrical contacts  56 . Data is stored in a serial flash memory circuit, which supports read, erase and program operations over a communications bus. The flash memory  62  enables the microcontroller  61  to store digitized ECG data. The communications bus further enables the flash memory  62  to be directly accessed externally over the external connector  65  when the monitor recorder  14  is interfaced to a download station. 
     The circuitry  60  of the monitor recorder  14  further includes an actigraphy sensor  64  implemented as a 3-axis accelerometer. The accelerometer may be configured to generate interrupt signals to the microcontroller  61  by independent initial wake up and free fall events, as well as by device position. In addition, the actigraphy provided by the accelerometer can be used during post-monitoring analysis to correct the orientation of the monitor recorder  14  if, for instance, the monitor recorder  14  has been inadvertently installed upside down, that is, with the monitor recorder  14  oriented on the electrode patch  15  towards the patient&#39;s feet, as well as for other event occurrence analyses. 
     The microcontroller  61  includes an expansion port that also utilizes the communications bus. External devices, separately drawing power externally from the battery provided on the electrode patch  15  or other source, can interface to the microcontroller  61  over the expansion port in half duplex mode. For instance, an external physiology sensor can be provided as part of the circuitry  60  of the monitor recorder  14 , or can be provided on the electrode patch  15  with communication with the micro-controller  61  provided over one of the electrical contacts  56 . The physiology sensor can include an SpO 2  sensor, blood pressure sensor, temperature sensor, respiratory rate sensor, glucose sensor, airflow sensor, volumetric pressure sensing, or other types of sensor or telemetric input sources. In a further embodiment, a wireless interface for interfacing with other wearable (or implantable) physiology monitors, as well as data offload and programming, can be provided as part of the circuitry  60  of the monitor recorder  14 , or can be provided on the electrode patch  15  with communication with the micro-controller  61  provided over one of the electrical contacts  56 . 
     Finally, the circuitry  60  of the monitor recorder  14  includes patient-interfaceable components, including a tactile feedback button  66 , which a patient can press to mark events or to perform other functions, and a buzzer  67 , such as a speaker, magnetic resonator or piezoelectric buzzer. The buzzer  67  can be used by the microcontroller  61  to output feedback to a patient such as to confirm power up and initiation of ECG monitoring. Still other components as part of the circuitry  60  of the monitor recorder  14  are possible. 
     While the monitor recorder  14  operates under micro control, most of the electrical components of the electrode patch  15  operate passively.  FIG. 9  is a functional block diagram showing the circuitry  70  of the extended wear electrode patch  15  of  FIG. 3 . The circuitry  70  of the electrode patch  15  is electrically coupled with the circuitry  60  of the monitor recorder  14  through an external connector  74 . The external connector  74  is terminated through the set of pads  34  provided on the bottom of the non-conductive receptacle  25 , which electrically mate to corresponding electrical contacts  56  protruding from the bottom surface of the sealed housing  50  to electrically interface the monitor recorder  14  to the electrode patch  15 . 
     The circuitry  70  of the electrode patch  15  performs three primary functions. First, a battery  71  is provided in a battery compartment formed on the bottom surface of the non-conductive receptacle  25 . The battery  71  is electrically interfaced to the circuitry  60  of the monitor recorder  14  as a source of external power. The unique provisioning of the battery  71  on the electrode patch  15  provides several advantages. First, the locating of the battery  71  physically on the electrode patch  15  lowers the center of gravity of the overall wearable monitor  12  and thereby helps to minimize shear forces and the effects of movements of the patient and clothing. Moreover, the housing  50  of the monitor recorder  14  is sealed against moisture and providing power externally avoids having to either periodically open the housing  50  for the battery replacement, which also creates the potential for moisture intrusion and human error, or to recharge the battery, which can potentially take the monitor recorder  14  off line for hours at a time. In addition, the electrode patch  15  is intended to be disposable, while the monitor recorder  14  is a reusable component. Each time that the electrode patch  15  is replaced, a fresh battery is provided for the use of the monitor recorder  14 , which enhances ECG monitoring performance quality and duration of use. Finally, the architecture of the monitor recorder  14  is open, in that other physiology sensors or components can be added by virtue of the expansion port of the microcontroller  61 . Requiring those additional sensors or components to draw power from a source external to the monitor recorder  14  keeps power considerations independent of the monitor recorder  14 . Thus, a battery of higher capacity could be introduced when needed to support the additional sensors or components without effecting the monitor recorders circuitry  60 . 
     Second, the pair of ECG electrodes  38 ,  39  respectively provided on the distal and proximal ends of the flexible circuit  32  are electrically coupled to the set of pads  34  provided on the bottom of the non-conductive receptacle  25  by way of their respective circuit traces  33 ,  37 . The signal ECG electrode  39  includes a protection circuit  72 , which is an inline resistor that protects the patient from excessive leakage current. 
     Last, in a further embodiment, the circuitry  70  of the electrode patch  15  includes a cryptographic circuit  73  to authenticate an electrode patch  15  for use with a monitor recorder  14 . The cryptographic circuit  73  includes a device capable of secure authentication and validation. The cryptographic device  73  ensures that only genuine, non-expired, safe, and authenticated electrode patches  15  are permitted to provide monitoring data to a monitor recorder  14 . 
     The monitor recorder  14  continuously monitors the patient&#39;s heart rate and physiology.  FIG. 10  is a flow diagram showing a monitor recorder-implemented method  100  for monitoring ECG data for use in the monitor recorder  14  of  FIG. 3 . Initially, upon being connected to the set of pads  34  provided with the non-conductive receptacle  25  when the monitor recorder  14  is snapped into place, the microcontroller  61  executes a power up sequence (step  101 ). During the power up sequence, the voltage of the battery  71  is checked, the state of the flash memory  62  is confirmed, both in terms of operability check and available capacity, and microcontroller operation is diagnostically confirmed. In a further embodiment, an authentication procedure between the microcontroller  61  and the electrode patch  15  are also performed. 
     Following satisfactory completion of the power up sequence, an iterative processing loop (steps  102 - 109 ) is continually executed by the microcontroller  61 . During each iteration (step  102 ) of the processing loop, the ECG frontend  63  (shown in  FIG. 8 ) continually senses the cutaneous ECG electrical signals (step  103 ) via the ECG electrodes  38 ,  29  and is optimized to maintain the integrity of the P-wave. A sample of the ECG signal is read (step  104 ) by the microcontroller  61  by sampling the analog ECG signal output front end  63 .  FIG. 11  is a graph showing, by way of example, a typical ECG waveform  110 . The x-axis represents time in approximate units of tenths of a second. The y-axis represents cutaneous electrical signal strength in approximate units of millivolts. The P-wave  111  has a smooth, normally upward, that is, positive, waveform that indicates atrial depolarization. The QRS complex usually begins with the downward deflection of a Q wave  112 , followed by a larger upward deflection of an R-wave  113 , and terminated with a downward waveform of the S wave  114 , collectively representative of ventricular depolarization. The T wave  115  is normally a modest upward waveform, representative of ventricular depolarization, while the U wave  116 , often not directly observable, indicates the recovery period of the Purkinje conduction fibers. 
     Sampling of the R-to-R interval enables heart rate information derivation. For instance, the R-to-R interval represents the ventricular rate and rhythm, while the P-to-P interval represents the atrial rate and rhythm. Importantly, the PR interval is indicative of atrioventricular (AV) conduction time and abnormalities in the PR interval can reveal underlying heart disorders, thus representing another reason why the P-wave quality achievable by the extended wear ambulatory electrocardiography and physiological sensor monitor described herein is medically unique and important. The long-term observation of these ECG indicia, as provided through extended wear of the wearable monitor  12 , provides valuable insights to the patient&#39;s cardiac function and overall well-being. 
     Each sampled ECG signal, in quantized and digitized form, is temporarily staged in buffer (step  105 ), pending compression preparatory to storage in the flash memory  62  (step  106 ). Following compression, the compressed ECG digitized sample is again buffered (step  107 ), then written to the flash memory  62  (step  108 ) using the communications bus. Processing continues (step  109 ), so long as the monitoring recorder  14  remains connected to the electrode patch  15  (and storage space remains available in the flash memory  62 ), after which the processing loop is exited and execution terminates. Still other operations and steps are possible. 
     In a further embodiment, physiological monitoring and data collection, such as per the method  100  described above with reference to  FIG. 10 , can also be implemented by a continuously-recording subcutaneous insertable cardiac monitor (ICM), such as one described in commonly-owned U.S. patent application Ser. No. 15/832,385, filed Dec. 5, 2017, pending, the disclosure of which is incorporated by reference. The ICM can be used for conducting a long-term electrocardiographic and physiological monitoring over a period lasting up to several years in duration.  FIG. 12  is a diagram showing, by way of example, a subcutaneous P-wave centric ICM  212  for long term electrocardiographic monitoring in accordance with one embodiment. The ICM  212  is implanted in the parasternal region  211  of a patient  10 . The sensing circuitry and components, compression algorithms, and the physical layout of the electrodes are specifically optimized to capture electrical signals from the propagation of low amplitude, relatively low frequency content cardiac action potentials, particularly the P-waves generated during atrial activation. The position and placement of the ICM  212  coupled to engineering considerations that optimize the ICM&#39;s sensing circuitry, discussed infra, aid in demonstrating the P-wave clearly. 
     Implantation of a P-wave centric ICM  212  in the proper subcutaneous site facilitates the recording of high quality ECG data with a good delineation of the P-wave. In general, the ICM  212  is intended to be implanted anteriorly and be positioned axially and slightly to either the right or left of the sternal midline in the parasternal region  211  of the chest, or if sufficient subcutaneous fat exists, directly over the sternum. Optimally, the ICM  212  is implanted in a location left parasternally to bridge the left atrial appendage. However, either location to the right or left of the sternal midline is acceptable; placement of the device, if possible, should bridge the vertical height of the heart, which lies underneath the sternum  203 , thereby placing the ICM  212  in close proximity to the anterior right atrium and the left atrial appendage that lie immediately beneath. 
     The ICM  212  is shaped to fit comfortably within the body under the skin and to conform to the contours of the patient&#39;s parasternal region  211  when implanted immediately to either side of the sternum  203 , but could be implanted in other locations of the body. In most adults, the proximal end  213  of the ICM  212  is generally positioned below the manubrium  8  but, depending upon patient&#39;s vertical build, the ICM  212  may actually straddle the region over the manubrium  8 . The distal end  214  of the ICM  212  generally extends towards the xiphoid process  9  and lower sternum but, depending upon the patient&#39;s build, may actually straddle the region over or under the xiphoid process  9 , lower sternum and upper abdomen. 
     Although internal tissues, body structures, and tissue boundaries can adversely affect the current strength and signal fidelity of all body surface potentials, subsurface low amplitude cardiac action potentials, particularly P-wave signals with a normative amplitude of less than 0.25 millivolts (mV) and a normative duration of less than 120 milliseconds (ms), are most apt to be negatively impacted by these factors. The atria, which generate the P wave, are mostly located posteriorly within the thoracic cavity (with the exception of the anterior right atrium, right atrial appendage and left atrial appendage). The majority of the left atrium constitutes the portion of the heart furthest away from the surface of the skin on the chest and harbors the atrial tissue most likely to be the source of serious arrhythmias, like atrial fibrillation. Conversely, the ventricles, which generate larger amplitude signals, are located anteriorly as in the case of the anterior right ventricle and most of the anterior left ventricle situated relatively close to the skin surface of the central and left anterior chest. These factors, together with larger size and more powerful impulse generation from the ventricles, contribute to the relatively larger amplitudes of ventricular waveforms. 
     Nevertheless, as explained supra, both the P-wave and the R-wave are required for the physician to make a proper rhythm diagnosis from the dozens of arrhythmias that can occur. Yet, the quality of P-waves is more susceptible to weakening from distance and the intervening tissues and structures and from signal attenuation and signal processing than the high voltage waveforms associated with ventricular activation. The added value of avoiding further signal attenuation resulting from dermal impedance makes a subcutaneous P-wave centric ICM even more likely to match, or even outperform dermal ambulatory monitors designed to analogous engineering considerations and using similar sensing circuitry and components, compression algorithms, and physical layout of electrodes, such as described in U.S. Pat. No. 9,545,204, issued January 217, 20217 to Bishay et al.; U.S. Pat. No. 9,730,593, issued Aug. 15, 20217 to Felix et al.; U.S. Pat. No. 9,700,227, issued Jul. 11, 20217 to Bishay et al.; U.S. Pat. No. 9,7217,433, issued Aug. 1, 20217 to Felix et al.; and U.S. Pat. No. 9,615,763, issued Apr. 11, 20217 to Felix et al., the disclosures of which are incorporated by reference. 
     The ICM  212  can be implanted in the patient&#39;s chest using, for instance, a minimally invasive subcutaneous implantation instrument or other suitable surgical implement. The ICM  212  is positioned slightly to the right or left of midline, covering the center third of the chest, roughly between the second and sixth ribs, approximately spanning between the level of the manubrium  8  and the level of the xiphoid process  9  on the inferior border of the sternum  203 , depending upon the vertical build of the patient  210 . 
     During monitoring, the amplitude and strength of action potentials sensed by an ECG devices, including dermal ECG monitors and ICMs, can be affected to varying degrees by cardiac, cellular, extracellular, vector of current flow, and physical factors, like obesity, dermatitis, lung disease, large breasts, and high impedance skin, as can occur in dark-skinned individuals. Performing ECG sensing subcutaneously in the parasternal region  211  significantly improves the ability of the ICM  212  to counter some of the effects of these factors, particularly high skin impedance and impedance from subcutaneous fat. Thus, the ICM  212  exhibits superior performance when compared to conventional dermal ECG monitors to existing implantable loop recorders, ICMs, and other forms of implantable monitoring devices by virtue of its engineering and proven P-wave documentation above the skin, as discussed in W. M. Smith et al., “Comparison of diagnostic value using a small, single channel, P-wave centric sternal ECG monitoring patch with a standard 3-lead Holter system over 24 hours,” Am. Heart J., March 20217; 2185:67-73, the disclosure of which is incorporated by reference. 
     Moreover, the sternal midline implantation location in the parasternal region  211  allows the ICM&#39;s electrodes to record an ECG of optimal signal quality from a location immediately above the strongest signal-generating aspects of the atrial. Signal quality is improved further in part because cardiac action potential propagation travels simultaneously along a north-to-south and right-to-left vector, beginning high in the right atrium and ultimately ending in the posterior and lateral region of the left ventricle. Cardiac depolarization originates high in the right atrium in the SA node before concurrently spreading leftward towards the left atrium and inferiorly towards the atrioventricular (AV) node. On the proximal end  213 , the ECG electrodes of the ICM  212  are subcutaneously positioned with the upper or superior pole (ECG electrode) slightly to the right or left of the sternal midline in the region of the manubrium  8  and, on the distal end  214 , the lower or inferior pole (ECG electrode) is similarly situated slightly to the right or left of the sternal midline in the region of the xiphoid process  9  and lower sternum  203 . The ECG electrodes of the ICM  212  are placed primarily in a north-to-south orientation along the sternum  203  that corresponds to the north-to-south waveform vector exhibited during atrial activation. This orientation corresponds to the aVF lead used in a conventional 12-lead ECG that is used to sense positive or upright P-waves. In addition, the electrode spacing and the electrodes&#39; shapes and surface areas mimic the electrodes used in the ICM&#39;s dermal cousin, designed as part of the optimal P-wave sensing electrode configuration, such as provided with the dermal ambulatory monitors cited supra. 
     Despite the challenges faced in capturing low amplitude cardiac action potentials, the ICM  212  is able to operate effectively using only two electrodes that are strategically sized and placed in locations ideally suited to high fidelity P-wave signal acquisition. This approach has been shown to clinically outperform more typical multi-lead monitors because of the improved P-wave clarity, as discussed in W. M. Smith et al., cited supra.  FIGS. 13 and 14  are respectively top and bottom perspective views showing the ICM  212  of  FIG. 1 . Physically, the ICM  212  is constructed with a hermetically sealed implantable housing  215  with at least one ECG electrode forming a superior pole on the proximal end  213  and at least one ECG electrode forming an inferior pole on the distal end  214 . 
     When implanted, the housing  215  is oriented most cephalad. The housing  215  is constructed of titanium, stainless steel or other biocompatible material. The housing  215  contains the sensing, recordation and interfacing circuitry of the ICM  212 , plus a long life battery. A wireless antenna is integrated into or within the housing  215  and can be positioned to wrap around the housing&#39;s internal periphery or location suited to signal reception. Other wireless antenna placement or integrations are possible. 
     Physically, the ICM  212  has four ECG electrodes  216 ,  217 ,  218 ,  219 . There could also be additional ECG electrodes, as discussed infra. The ECG electrodes include two ventral (or dorsal) ECG electrodes  218 ,  219  and two wraparound ECG electrodes  216 ,  217 . One ventral ECG electrode  218  is formed on the proximal end  213  and one ventral ECG electrode  219  is formed on the distal end  214 . One wraparound ECG electrode  216  is formed circumferentially about the proximal end  213  and one wraparound ECG electrode  217  is formed circumferentially about the distal end  214 . Each wraparound ECG electrode  216 ,  217  is electrically insulated from its respective ventral ECG electrode  218 ,  219  by a periphery  220 ,  221 . 
     The four ECG electrodes  216 ,  217 ,  218 ,  219  are programmatically controlled by a microcontroller through onboard firmware programming to enable a physician to choose from several different electrode configurations that vary the electrode surface areas, shapes, and inter-electrode spacing. The sensing circuitry can be programmed, either pre-implant or in situ, to use different combinations of the available ECG electrodes (and thereby changing electrode surface areas, shapes, and inter-electrode spacing), including pairing the two ventral ECG electrodes  216 ,  217 , the two wraparound ECG electrodes  218 ,  219 , or one ventral ECG electrode  216 ,  217  with one wraparound ECG electrode  218 ,  219  located on the opposite end of the housing  215 . In addition, the periphery  220 ,  221  can be programmatically controlled to logically combine the wraparound ECG electrode  216 ,  217  on one end of the ICM  212  with its corresponding ventral ECG electrode  218 ,  219  to form a single virtual ECG electrode with larger surface area and shape. (Although electronically possible, the two ECG electrodes that are only on one end of the ICM  212 , for instance, wraparound ECG electrode  216  and ventral ECG electrode  218 , could be paired; however, the minimal inter-electrode spacing would likely yield a signal of poor fidelity in most situations.) 
     In a further embodiment, the housing  215  and contained circuitry can be provided as a standalone ICM core assembly to which a pair of compatible ECG electrodes can be operatively coupled to form a full implantable ICM device. 
     Other ECG electrode configurations are possible. For instance, additional ECG electrodes can be provided to increase the number of possible electrode configurations, all of which are to ensure better P-wave resolution.  FIG. 15  is a bottom perspective view showing the ICM  212  of  FIG. 12  in accordance with a further embodiment. An additional pair of ventral ECG electrodes  222 ,  223  are included on the housing&#39;s ventral surface. These ventral ECG electrodes  222 ,  223  are spaced closer together than the ventral ECG electrodes  218 ,  219  on the ends of the housing  215  and a physician can thus choose to pair the two inner ventral ECG electrodes  222 ,  223  by themselves to allow for minimal electrode-to-electrode spacing, or with the other ECG electrodes  216 ,  217 ,  218 ,  219  to vary electrode surface areas, shapes, and inter-electrode spacing even further to explore optimal configurations to acquire the P-wave. 
     Other housing configurations of the ICM are possible. For instance, the housing of the ICM can be structured to enhance long term comfort and fitment, and to accommodate a larger long life battery or more circuitry or features, including physiologic sensors, to provide additional functionality.  FIGS. 16 and 17  are respectively top and bottom perspective views showing an ICM  230  in accordance with a still further embodiment. The ICM  230  has a housing  231  with a tapered extension  232  that is terminated on the distal end with an electrode  234 . On a proximal end, the housing  231  includes a pair of ECG electrodes electrically insulated by a periphery  237  that include a ventral ECG electrode  233  and a wraparound ECG electrode  234 . In addition, a ventral ECG electrode  236  is oriented on the housing&#39;s distal end before the tapered extension  232 . Still other housing structures and electrode configurations are possible. 
     In general, the basic electrode layout is sufficient to sense cardiac action potentials in a wide range of patients. Differences in thoracic tissue density and skeletal structure from patient to patient, though, can affect the ability of the sensing electrodes to efficaciously capture action potential signals, yet the degree to which signal acquisition is affected may not be apparent until after an ICM has been implanted and deployed, when the impacts of the patient&#39;s physical constitution and his patterns of mobility and physical movement on ICM monitoring can be fully assessed. 
     In further embodiments, the electrodes can be configured post-implant to allow the ICM to better adapt to a particular patient&#39;s physiology. For instance, electrode configurations having more than two sensing electrodes are possible.  FIG. 18  is a plan view showing further electrode configurations. Referring first to  FIG. 18( a ) , a single disc ECG electrode  240  could be bifurcated to form a pair of half-circle ECG electrodes  241 ,  242  that could be programmatically selected or combined to accommodate a particular patients ECG signal characteristics post-ICM implant. Referring next to  FIG. 18( b ) , a single disc ECG electrode  245  could be divided into three sections, a pair of crescent-shaped ECG electrodes  246 ,  247  surrounding a central semicircular ECG electrode  248  that could similarly be programmatically selected or combined. Still other ECG electrode configurations are possible. 
     ECG monitoring and other functions performed by the ICM  212  are provided through a micro controlled architecture.  FIG. 19  is a functional block diagram showing the P-wave focused component architecture of the circuitry  280  of the ICM  212  of  FIG. 12 . The circuitry  280  is powered through the long life battery  21  provided in the housing  215 , which can be a direct current battery. Operation of the circuitry  280  of the ICM  212  is managed by a microcontroller  281 , such as the EFM32 Tiny Gecko 32-bit microcontroller, manufactured by Silicon Laboratories Inc., Austin, Tex. The microcontroller  281  has flexible energy management modes and includes a direct memory access controller and built-in analog-to-digital and digital-to-analog converters (ADC and DAC, respectively). The microcontroller  281  also includes a program memory unit containing internal flash memory (not shown) that is readable, writeable, and externally programmable. 
     The microcontroller  281  operates under modular micro program control as specified in firmware stored in the internal flash memory. The microcontroller  281  draws power from the battery provided in the housing  215  and connects to the ECG front end circuit  63 . The front end circuit  63  measures raw subcutaneous electrical signals using a driven reference signal that eliminates common mode noise, as further described infra. 
     The circuitry  280  of the ICM  212  also includes a flash memory  282  external to the microcontroller  281 , which the microcontroller  281  uses for continuously storing samples of ECG monitoring signal data and other physiology, such as respiratory rate, blood oxygen saturation level (SpO 2 ), blood pressure, temperature sensor, and physical activity, and device and related information. The flash memory  282  also draws power from the battery provided in the housing  215 . Data is stored in a serial flash memory circuit, which supports read, erase and program operations over a communications bus. The flash memory  282  enables the microcontroller  281  to store digitized ECG data. The communications bus further enables the flash memory  282  to be directly accessed wirelessly through a transceiver  285  coupled to an antenna  217  built into (or provided with) the housing  215 . The transceiver  285  can be used for wirelessly interfacing over Bluetooth or other types of wireless technologies for exchanging data over a short distance with a paired mobile device, including smartphones and smart watches, that are designed to communicate over a public communications infrastructure, such as a cellular communications network, and, in a further embodiment, other wearable (or implantable) physiology monitors, such as activity trackers worn on the wrist or body. Other types of device pairings are possible, including with a desktop computer or purpose-built bedside monitor. The transceiver  285  can be used to offload stored ECG monitoring data and other physiology data and information and for device firmware reprogramming. In a further embodiment, the flash memory  282  can be accessed through an inductive coupling (not shown). 
     The microcontroller  281  includes functionality that enables the acquisition of samples of analog ECG signals, which are converted into a digital representation, implementing the method  100  described supra with reference to  FIG. 10 . In one mode, the microcontroller  281  implements a loop recorder feature that will acquire, sample, digitize, signal process, and store digitized ECG data into available storage locations in the flash memory  282  until all memory storage locations are filled, after which existing stored digitized ECG data will either be overwritten through a sliding window protocol, albeit at the cost of potentially losing the stored data that was overwritten, if not previously downloaded, or transmitted wirelessly to an external receiver to unburden the flash memory. In another mode, the stored digitized ECG data can be maintained permanently until downloaded or erased to restore memory capacity. Data download or erasure can also occur before all storage locations are filled, which would free up memory space sooner, albeit at the cost of possibly interrupting monitoring while downloading or erasure is performed. Still other modes of data storage and capacity recovery are possible. 
     The circuitry  280  of the ICM  212  can include functionality to programmatically select pairings of sensing electrodes when the ICM  212  is furnished with three or more electrodes. In a further embodiment, multiple sensing electrodes could be provided on the ICM  212  to provide a physician the option of fine-tuning the sensing dipole (or tripole or multipole) in situ by parking active electrodes and designating any remaining electrodes inert. The pairing selection can be made remotely through an inductive coupling or by the transceiver  285  via, for instance, a paired mobile device, as further described infra. Thus, the sensing electrode configuration, including number of electrodes, electrode-to-electrode spacing, and electrode size, shape, surface area, and placement, can be modified at any time during the implantation of the ICM  212 . 
     In a further embodiment, the circuitry  280  of the ICM  212  can include an actigraphy sensor  284  implemented as a 3-axis accelerometer. The accelerometer may be configured to generate interrupt signals to the microcontroller  281  by independent initial wake up and free fall events, as well as by device position. In addition, the actigraphy provided by the accelerometer can be used during post-monitoring analysis to correct the orientation of the ICM  212  if, for instance, the ICM  212  has been inadvertently implanted upside down, that is, with the ICM&#39;s housing oriented caudally, as well as for other event occurrence analyses. 
     In a still further embodiment, the circuitry  280  of the ICM  212  can include one or more physiology sensors. For instance, a physiology sensor can be provided as part of the circuitry  280  of the ICM  212 , or can be provided on the electrode assembly  214  with communication with the microcontroller  281  provided through a circuit trace. The physiology sensor can include an SpO 2  sensor, blood pressure sensor, temperature sensor, respiratory rate sensor, glucose sensor, airflow sensor, volumetric pressure sensing, or other types of sensor or telemetric input sources. 
     In a yet further embodiment, firmware with programming instructions, including machine learning and other forms of artificial intelligence-originated instructions, can be downloaded into the microcontroller&#39;s internal flash memory. The firmware can include heuristics to signal patient and physician with alerts over health conditions or arrhythmias of selected medical concern, such as where a heart pattern particular to the patient is identified and the ICM  212  is thereby reprogrammed to watch for a reoccurrence of that pattern, after which an alert will be generated and sent to the physician (or other caregiver) through the transceiver  285  via, for instance, a paired mobile device. Similarly, the firmware can include heuristics that can be downloaded to the ICM  212  to actively identify or narrow down a pattern (or even the underlying cause) of sporadic cardiac conditions, for instance, atrial tachycardia (AT), atrial fibrillation (AF), atrial flutter (AFL), AV node reciprocating tachycardia, ventricular tachycardia (VT), sinus bradycardia, asystole, complete heart block, and other cardiac arrhythmias, again, after which an alert will be generated and sent to the physician (or other caregiver) through the transceiver  285 . For instance, an alert that includes a compressed ECG digitized sample can also be wirelessly transmitted by the ICM  212  upon the triggering of a preset condition, such as an abnormally low heart rate in excess of 170 beats per minute (bpm), an abnormally low heart rate falling below 30 bpm, or AF detected by onboard analysis of RR interval variability by the microcontroller  281 . Finally, a similar methodology of creating firmware programming tailored to the monitoring and medical diagnostic needs of a specific patient (or patient group or general population) can be used for other conditions or symptoms, such as syncope, palpitations, dizziness and giddiness, unspecified convulsions, abnormal ECG, transient cerebral ischemic attacks and related syndromes, cerebral infarction, occlusion and stenosis of pre-cerebral and cerebral arteries not resulting in cerebral infarction personal history of transient ischemic attack, and cerebral infarction without residual deficits, to trigger an alert and involve the physician or initiate automated analysis and follow up back at the patient&#39;s clinic. Finally, in a still further embodiment, the circuitry  280  of the ICM  212  can accommodate patient-interfaceable components, including an external tactile feedback device (not shown) that wirelessly interfaces to the ICM  212  through the transceiver  285 . A patient  210  can press the external tactile feedback device to mark events, such as a syncope episode, or to perform other functions. The circuitry  280  can also accommodate triggering an external buzzer  67 , such as a speaker, magnetic resonator or piezoelectric buzzer, implemented as part of the external tactile feedback device or as a separate wirelessly-interfaceable component. The buzzer  67  can be used by the microcontroller  281  to indirectly output feedback to a patient  210 , such as a low battery or other error condition or warning. Still other components, provided as either part of the circuitry  280  of the ICM  212  or as external wirelessly-interfaceable devices, are possible. 
     The ECG front end circuit  283  of the ICM  12  measures raw subcutaneous electrical signals using a driven reference signal, such as described in U.S. Pat. Nos. 9,700,227, 9,717,433, and 9,615,763, cited supra. The driven reference signal effectively reduces common mode noise, power supply noise and system noise, which is critical to preserving the characteristics of low amplitude cardiac action potentials, especially the P wave signals originating from the atria. 
     The ECG front end circuit  283  is organized into a passive input filter stage, a unity gain voltage follower stage, a passive high pass filtering stage, a voltage amplification and active filtering stage, and an anti-aliasing passive filter stage, plus a reference generator. The passive input filter stage passively shifts the frequency response poles downward to counter the high electrode impedance from the patient on the signal lead and reference lead, which reduces high frequency noise. The unity gain voltage follower stage allows the circuit to accommodate a very high input impedance, so as not to disrupt the subcutaneous potentials or the filtering effect of the previous stage. The passive high pass filtering stage includes a high pass filter that removes baseline wander and any offset generated from the previous stage. As necessary, the voltage amplification and active filtering stage amplifies or de-amplifies (or allows to pass-through) the voltage of the input signal, while applying a low pass filter. The anti-aliasing passive filter stage provides an anti-aliasing low pass filter. The reference generator drives a driven reference signal containing power supply noise and system noise to the reference lead and is connected directly to the patient, thereby avoiding the thermal noise of the protection resistor that is included as part of the protection circuit. 
     Once collected, the ECG data is offloaded from the cardiac monitor to a database, computer, or mobile device via a wired or wireless connection. The ECG data can be stored or collected in real time, and can be transferred through a physical connection, a short-range wireless connection, or a network-based connection.  FIG. 20  is a functional block diagram showing a system  300  for obtaining ECG data from a cardiac monitor, in accordance with one embodiment. The cardiac monitor  301  can be dermally positioned on a patient or can be implanted for monitoring ECG data, which can be offloaded for storage and further processing. 
     Physical Download Station 
     In one embodiment, when dermally positioned, the cardiac monitor  301  can be connected to a download station  302 , which could be a programmer or other device that permits the retrieval of stored ECG monitoring data, execution of diagnostics on or programming of the monitor  301 , or performance of other functions, via a receptacle  303 . In turn, the download station  125  executes a communications or offload program  304  (“Offload”) or similar program that interacts with the cardiac monitor  301  via the physical interface to retrieve the stored ECG monitoring data. The download station  302  could be a server, personal computer, tablet or handheld computer, smart mobile device, or purpose-built programmer designed specific to the task of interfacing with a monitor recorder  14 . Still other forms of download stations  302  are possible. Generally, the download station is located in a physician&#39;s office, in which the patient must be present. Alternatively, the patient can send in the dermal device for offloading the ECG data. Whether the patient is located in the office or sends in the device, real-time ECG data cannot be accessed since the cardiac monitor is removed from the patient. 
     Upon retrieving stored ECG monitoring data from the cardiac monitor  301 , middleware first operates on the retrieved data to adjust the ECG capture quality, as necessary, and to convert the retrieved data into a format suitable for use by third party post-monitoring analysis software. The formatted data can then be retrieved from the download station  302  over a hard link  313  using a control program  314  (“Ctl”) or analogous application executing on a personal computer  315  or other connectable computing device, via a communications link (not shown), whether wired or wireless, or by physical transfer of storage media (not shown). The personal computer  315  or other connectable device may also execute middleware that converts ECG data and other information into a format suitable for use by a third-party post-monitoring analysis program. In a further embodiment, the download station  302  is able to directly interface with other devices over a computer communications network  312 , which could be some combination of a local area network and a wide area network, including the Internet, over a wired or wireless connection. 
     A client-server model could be used to employ a server  308  to remotely interface with the download station  302  over the network  312  and retrieve the formatted data or other information. The server  308  executes a patient management program  316  (“Mgt”) or similar application that stores the retrieved formatted data and other information in a secure database  309  cataloged in that patient&#39;s EMRs  310 . The patient management program  316 , or other trusted application, also maintains and safeguards the secure database  309  to limit access to patient EMRs  310  to only authorized parties for appropriate medical or other uses, such as mandated by state or federal law, such as under the Health Insurance Portability and Accountability Act (HIPAA) or per the European Union&#39;s Data Protection Directive. 
     Short-Range Wireless Connection 
     In a further embodiment, the cardiac monitor  301 , whether dermally positioned or implanted, can interoperate wirelessly with other wearable physiology and activity sensors  305  and with wearable or mobile communications devices  306 . Further, the cardiac monitor can function as a physiological monitor to measure not only ECG data, but other types of physiological measures, such as oxygen levels and blood glucose levels. Other types of physiological monitors and measures are possible. Wearable physiology and activity sensors  305  encompass a wide range of wirelessly interconnectable devices that measure or monitor data physical to the patient&#39;s body, such as heart rate, temperature, blood pressure, and so forth; physical states, such as movement, sleep, footsteps, and the like; and performance, including calories burned or estimated blood glucose level. These devices originate both within the medical community to sense and record traditional medical physiology that could be useful to a physician in arriving at a patient diagnosis or clinical trajectory, as well as from outside the medical community, from, for instance, sports or lifestyle product companies who seek to educate and assist individuals with self-quantifying interests. 
     Each of the wearable physiology and activity sensors and the wearable or mobile communications devices can communicate via a short-range wireless connection, such as Bluetooth, with the cardiac monitor. However, due to the short-range connection, the patient must be proximate to the sensors and the communications devices. 
     The wearable physiology and activity sensor  305  and the wearable or mobile communications devices  306  could also serve as a conduit for providing the data collected by the wearable physiology and activity sensor  305  to a server  308 . The server  308  could then merge the collected data into the wearer&#39;s electronic medical records, EMRs,  310  in the secure database  309 , if appropriate (and permissible), or the server  308  could perform an analysis of the collected data, perhaps based by comparison to a population of like wearers of the wearable physiology and activity sensor  305 . Further, the ECG data can be provided to a remotely located physician or other medical professional for review. However, even though the ECG data may be transferred in real time from the cardiac monitor to the wearable physiology and activity sensor  305  or the wearable or mobile communications devices  306  via Bluetooth, the ECG data is delayed to the remote physician due to the authentication required when the data is transferred over the network to the server. 
     Alternatively, the wearable physiology and activity sensors  305  are capable of wireless interfacing with wearable or mobile communications devices  306 , particularly smart mobile devices, including so-called “smart phones,” to download monitoring data either in real-time or in batches. The wearable or mobile communications device  306  executes an application (“App”)  307  that can retrieve the data collected by the wearable physiology and activity sensor  305  and evaluate the data to generate information of interest to the wearer, such as an estimation of the effectiveness of the wearer&#39;s exercise efforts. Still other wearable or mobile communications device  306  functions on the collected data are possible. 
     In a further embodiment, a wireless data transfer device can be placed over the patient&#39;s chest at a location of the cardiac monitor  301  and the ECG data can be transferred to a computer or mobile device via the wireless data transfer device. In one embodiment, such transfer of data can occur via Bluetooth since the patient must be located in the physician&#39;s office or medical facility. The ECG data can subsequently be transferred from the data transfer device to a server via a network. As described above, transfer of the ECG data over the network to a web server is delayed due to the authentication process. 
     Network-Based Communication 
     In addition, the cardiac monitor  301  could wirelessly interface directly with the server  308 , personal computer  311 , or other computing device connectable over the network  312 , when the cardiac monitor  301  is appropriately equipped for interfacing with such devices. However, a delay of the data is created and a remote medical professional is unable to access the ECG data in real time. Specifically, in internet-based connections, such as between the puck or cardiac monitor to the web server, the transfer of ECG data is too slow to provide real-time or near real-time streaming of the data to a remote viewer, such as a medical professional. Generally, for real-time or near real-time viewing of ECG data a one second delay or shorter is required. When the ECG data is first transferred to a web server via a network, a secure connection must be established, such as via the TLS Handshake Protocol that is responsible for authenticating new secure sessions and resuming previous secure sessions. Although secure, such connection requires time to establish, which delays the ECG data being accessed and provided to the physician or medical professional. 
     To reduce the amount of time establishing a connection for the transfer of ECG data, a continuous data connection can be established.  FIG. 21  is a functional block diagram showing a system  320  for real-time remote streaming of ECG data, in accordance with one embodiment. A cardiac monitor  322  is dermally positioned or implanted in a patient  321  to capture cardiac action potentials sensed by ECG sensing electrodes which are output as ECG signals. The cardiac monitor  322  can include, at a minimum, a pair of electrodes, a battery, processor, front end, memory, and a wireless transceiver. In one embodiment, the wireless transceiver can include a Near-field communication (NFC) chip that controls the exchange of data between the cardiac monitor  322  and external devices at a short-range, though other communication protocols can also be used by the transceiver at a short range. The presence of NFC or other communication protocols allows the wireless transceiver to implement a cryptographic security protocol with an external device, protecting data being exchanged. 
     In one embodiment, the ECG data can be offloaded directly from the cardiac monitor  322  via a wireless connection, over an internetwork  325 , such as the Internet, to a server  326  in the cloud. Specifically, the ECG data is first encrypted by the cardiac monitor, such as via the NFC chip, and a continuous connection is established with the cloud server  326 . The cloud server  326  then transfers the ECG data in real time to a physician or other medical professional  328  via a computing device, such as a computer, tablet, or cellular phone  327 . 
     In a further embodiment, a data transfer device, such as a puck  324 , can be used to obtain data from the cardiac monitor  322 . The puck  324  can be shaped as a circle, oval, or computer mouse, and can be pressed against (or held close to) the patient&#39;s chest in the parasternal region over the cardiac monitor  322  to access ECG data and provide charging to the cardiac monitor  322 . Other shapes of the puck  324  are possible. At a minimum, the puck should include a housing, processor, battery, memory, and a wireless transceiver or NFC chip. The puck  322  can access the ECG data from the cardiac monitor  322  via the wireless transceiver or an NFC chip. If the ECG data is not already encrypted, the puck  324  can encrypt the ECG data. Once obtained, the puck  324  can transmit the encrypted ECG data to the cloud server  326  or to a home station  323 . 
     Specifically, the puck  324  can include a data download module (not shown), which uses an internal wireless transceiver to wirelessly download data collected by the cardiac monitor  322  by interfacing with the wireless transceiver cardiac monitor. The downloading of the ECG data can happen simultaneously to charging of the cardiac monitor by the puck, as described below. The downloaded physiological data can in turn be wirelessly forwarded to a home station or the cloud server. 
     The home station  323  can be located at the patient&#39;s home, such as near the patient&#39;s bed, and can include a housing, processor, inductive battery charger, control circuit, memory, and wireless transceiver or NFC chip. The home station  323  can be used to communicate data to and from the cardiac monitor  322 , program the cardiac monitor, and charge the puck  324 . The data can include ECG data, as well as other types of physiological data, obtained by the cardiac monitor, such as respirator rate, blood glucose levels, and oxygen levels, and can be collected at least once a day or over longer periods of time. In a further embodiment, the cardiac monitor  322  can communicate the ECG data and physiological data directly to the home station  323 , without the use of the puck  324 . 
     Cardiac or other types of physiological monitors, whether dermally placed on a patient or implanted, are not usually responsible for creating or initiating a secure communication channel, but can do so by including a cryptographic key or a series of cryptographic keys in the cardiac monitor. The cryptographic key would allow communication to be encrypted and to only be decrypted by an authorized receiver such as a cloud server. All the data, including ECG and other physiological data, transferred between the cardiac monitor and cloud server would be encrypted with the encryption based on the keys stored in the server and device, even if the data first goes through a gateway, the gateway would be unable to decrypt the data. The cardiac and physiological monitors can be positioned dermally on a patient or implanted, such as those devices described in detail in U.S. Provisional Patent Application No. 62/874,086, filed Jul. 15, 2019; U.S. Provisional Patent Application No. 62/873,740, filed Jul. 12, 2019; and U.S. Provisional Patent Application No. 62/962,773, filed Jan. 17, 2020, the disclosures of which are incorporated by reference and cover a configurable hardware platform for health and medical monitoring of physiology that is housed within a hermetically sealed implantable medical device (IMD). In one embodiment, the IMD is equipped with one or more physiological sensors that non-exhaustively include ECG, temperature, oxygen saturation, respiration, and blood glucose. Physically, the IMD has a generally tubular shape that includes a central tubular body with rounded semi spherical ends. When configured to measure electrocardiographic signals, the central tubular body and one of the semi spherical ends function as electrode dipoles. That semi spherical end is electrically conductive yet electrically insulated from the central tubular body. As well, the outside surface of the central tubular body is partially electrically insulated, generally on the surface closest to the electrically conductive semi spherical end to form a non-electrically conductive inversion with only the outside surface distal to that semi spherical end being exposed. When placed within the central tubular body, a foldable printed circuit board (PCB) forms three aspects that respectively define a coil for capture of magnetic fields used in energy transfer, an additional high frequency antenna for radio frequency (RF) data exchange, and a central folded flex circuit containing a microcontroller and device circuitry. A power source that includes a rechargeable battery is also placed within the 1 MB to one end of the folded PCB and in electrical contact through a protection circuit with the electrically conductive semi spherical end, thereby serving as an electrical feedthrough to the PCB. Another implementation may use the charging antenna as an insulator and to route the electrical signals from the spherical conductive end. The battery may be recharged using a non-contact method, such as inductive charging, resonant charging, energy harvesting, thermal gradient charging, ultrasonic charging, RF-based charging or charging by ambient or driven motion. Different types of recharging processes can be used as described in U.S. patent application Ser. No. 16/919,626, filed on Jul. 2, 2020, the disclosure of which is incorporated by reference. 
     The encrypted ECG data received on the home station  323 , from the puck or the cardiac monitor, can be delivered via WiFi or a cellular connection to the cloud server  326  and subsequently, to the physician  328  via a computer, tablet, or cellular phone  327 , without compromising data security due to the encryption of the data. The home station  323  maintains a continuous or intermittent connection with the cloud server  326 , which does not require authentication of the home station every time, including startup and a handshake protocol, which reduces an amount of time for a remote user, such as the physician, to receive the ECG data. Further, the home station  323  may include an inductive charger to charge the puck when not in use. 
     When applied to a patient, the energized puck  324  can charge the cardiac monitor  322 . For instance, the puck can include an energy transmission module (not shown) to provide input, such as magnetic or radio waves, that provides electrical energy to the cardiac monitor  322  during charging. For example, the energy transmission module can include a radio transmitter that radiates radio waves that can be captured by the cardiac monitor  322 , such as via an antenna. Alternatively, the ECG data can be transmitted via an inductive coil (not shown) included in the puck to generate a magnetic field that energizes an inductive coil within the cardiac monitor  322 . Charging of the cardiac monitor during data transfer is useful to prevent draining the battery during the transfer and to further power the battery for later use. 
     ECG streaming is useful for adjusting beat detection and noise detection parameters of the cardiac monitor to ensure that the ECG reports are accurate. Currently, beat detection and noise detection adjustments are made while the patient is present at the physician&#39;s office since the adjustments are generally based on real time ECG views. Other parameters, such as arrhythmia detection, can also occur. However, such parameters can be adjusted remotely using the remote real-time ECG streaming. In one example, beat detection can use the amplitude and change in volts per second to identify heart beats of the patient. Certain patterns can fool a beat detector and change the points in an R-R plot. Accordingly, accurately identifying beats is important. 
     In one embodiment, beat detection can occur on the cardiac monitor. Alternatively or in addition to the monitor, beat detection can occur on a server. The beat detection algorithm for the patient can be improved by comparing the beat detection results from the monitor with the beat detection results from the server. For example, the comparison can occur on the server, which can also do the tuning of the beat detection of the cardiac monitor. The updated beat parameters are then sent to the cardiac monitor. Such comparison can occur daily, such as part of a daily interrogation of data from the cardiac monitor. 
     In one example, beat detection may need to be adjusted for a patient. For instance, when a patient first receives an ICM, a fibrous capsule has not yet formed and the tissue is bleeding and swollen. As the patient recovers, the patient&#39;s cardiac signals usually grow and the beat detection algorithm should be adjusted. 
     In a further embodiment, direct transfer of ECG data from the cardiac monitor to the home station can also be useful in doctors&#39; offices. For example, patients with cardiac devices are sitting in a waiting room at the physician&#39;s office. While waiting, the cardiac devices can encrypt the ECG or other physiological data, and send the encrypted data to a home station located at the physician&#39;s office so that the data is readily available when the patient is called to see the doctor. Since the data is encrypted by the cardiac monitor, the data is secure despite the multiple monitors that are offloading data simultaneously. Further, the encrypted data can only be unencrypted in the cloud server. 
     Although the above has discussed real-time streaming of cardiac data, other types of physiological data can be streamed, oxygen rate, temperature, respiratory rate, blood glucose levels, and more. The monitors for the physiological data can be included on the cardiac monitor or can be separate from the cardiac monitor. 
     Data can be communicated between an implantable medical device (IMD), bedside monitor, and ECG backend or directly between an IMD and an ECG backend. The IMD can include a cardiac or physiology monitor, which is dermal or implanted. The terms IMD and ICM are used interchangeably within this application. The ECG backend can be a server that the bedside monitor communications with via WiFi, for example, on a hardware platform such as Raspberry Pi. However, other types of communication and communication devices are possible. The data exchange can be initiated by the IMD or the bedside monitor.  FIG. 22  is a block diagram showing, by way of example, ICM initiated data flow paths  400 . An ICM  401  can provide ECG data recorded by the ICM device, logs from components  406  of the ICM, and a status of the ICM components  406  to an ECG backend  403  via a bedside monitor  402 . The bedside monitor  402  can include a charging puck  405  or the charging puck  405  can be a device separate from the bedside monitor  402 . When separate, the bedside monitor  402  and charging puck  405  can be fixedly attached together or disconnectable. The bedside monitor  402  can transfer data without the charging puck  405 ; however, the charging puck  405  may need the bedside monitor  402  to charge. 
     In turn, the backend  403  can provide ICM components, firmware updates, and initial charge parameter of the ICM to the ICM  401  via the bedside monitor  402 . The backend server  403  can communicate with a customer portal  404 , such as a web application, to provide patient notifications, such as amount of ICM battery charge and date or time of last data transfer. The communication between the ECG backend  403  and customer portal  404  can occur via WiFi or other communication means. In one example, the data exchange can occur daily, multiple times a day, or after more than one day. 
     The bedside monitor can also initiate communication, rather than merely passing data between the ICM and ECG backend.  FIG. 23  is a block diagram showing, by way of example, a bedside monitor-initiated data flow  420 . The bedside monitor  402  can provide logs from bedside monitor components  421  and a status of the bedside monitor components  421  to the backend server  403 , while the backend server  403  can provide the bedside monitor  402  with bedside monitor components and firmware updates. The transfer of data can occur multiple times a day, once a day, or after more than one day. 
     The ICM can initiate charging upon identifying a status of low battery, such as communication from the ECG backend, in one embodiment.  FIG. 24  is a block diagram showing, by way of example, an ICM initiated charging data flow  430 . Charging of the ICM  401  can occur along different paths. For example, a first charging path can include a supervisor chip (STM  32 )  431  on the IMD  401 , which communicates with charging circuitry  432  on a puck  405  that can be attached to or separate from the bedside monitor  402 . In turn, the puck  405  communicates with the bedside monitor  402  via STM  32   437  to control the puck  405  and an amount of charge by generating a wave form via a communication bus (UART), which can be SPI. The charging can be initialized by the IMD  401  by providing charge parameters and updates to the charge parameters. During charging, data can also be communicated between the IM  401  and the bedside monitor  402  via the charge waveforms or by using Bluetooth. 
     A second charging path can include a Bluetooth module  433 , such as the RSL  10  SoC manufactured by On Semiconductor, on the IMD  401 , which communicates with a Bluetooth module  434  in the puck  405 , which then communicates with the bedside monitor  402 , such as via a Raspberry Pi hardware platform  435 . In a further example, the IMD  401  can be charged directly via the bedside monitor  402  without the puck  405 . For instance, the Bluetooth module  433  of the IMD  402  communicates with a Bluetooth module (RSL  10 )  436  of the bedside monitor  402 . 
     During charging, data can be transferred from the ICM  401  to the backend server  403  via the bedside monitor  402  or from the backend server  403  to the ICM  401  via the bedside monitor  402 . For example, the data can be offloaded from the ICM  401  via Bluetooth during charging based on one or more of the charging paths described above. Alternatively, the data can be transferred via data blanking during which charging can be automatically stopped once a certain amount of charge is reached while the data is transferred and once a predetermined amount of data has been transferred, charging can begin again. The data transfer can occur over multiple cycles of charging, data transfer, charging, data transfer, such as depending on an amount of data to be transferred and a speed of the data transfer. 
     When the ICM is not properly functioning, the ICM can contact the bedside monitor for assistance.  FIG. 25  is a block diagram showing, by way of example, a recovery mode data flow  440 . In recovery mode, the bedside monitor  402  can provide the IMD  401  with debug commands, while the IMD  102  provides error logs and bug reports to the bedside monitor  402 . Communication can occur via a path, which includes a supervisor chip (STM  32 )  431  on the IMD  401 , which communicates with charging circuitry  432  on a puck  405  that communicates with the bedside monitor  402  via STM  32   437 . 
     Communication can also occur between the bedside monitor and a user application for initiating WiFi.  FIG. 26  is a block diagram showing, by way of example, a bedside monitor WiFi provisioning data flow  450 , which is initiated by a user. The bedside monitor  402  can indicate available networks for use by the bedside monitor and strength of the networks, as well as a connected status, once available. The user can select a network and enter a password associated with the network to connect with the bedside monitor  402 . For instance, upon starting up the bedside monitor, WiFi provisioning can be run to allow the user to set up the bedside monitor by connecting the bedside monitor  402  to a user application  451  via Bluetooth and receiving available networks for WiFi. The user application  451  can obtain information from the ICM for review by or notification to the user. 
     Data collected by the ICM can be transferred to the ECG backend via a mobile application without use of the bedside monitor.  FIG. 27  is a block diagram showing, by way of example, an ICM initiated data flow  460 . The ICM  402  can provide data to the backend  403  via a mobile phone application  461 , instead of via the bedside monitor  402 . Specifically, the ICM  401  can provide ECG data, logs from ICM components  406 , and status of ICM components  406  to the backend  403  via the application  461 , while the backend  403  provides ICM components  406 , firmware updates and initial charge parameters to the ICM  401 . The application can be specific to a particular ICM or can be used for different types of ICMs. 
     While the invention has been particularly shown and described as referenced to the embodiments thereof, those skilled in the art will understand that the foregoing and other changes in form and detail may be made therein without departing from the spirit and scope.