Assessing cardiopulmonary resuscitation by an implantable medical device

Abstract

An example insertable cardiac monitor includes a plurality of electrodes to configured detect a cardiac electrical signal of a patient; a cardiac mechanical sensor configured to generate a cardiac mechanical signal; and processing circuitry configured to: determine cardiopulmonary resuscitation (CPR) is being administered to the patient; in response to the determination that CPR is being administered to the patient, determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on the cardiac electrical signal; and in response to a determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time based on a cardiac mechanical signal sensed via the cardiac mechanical sensor during the period of time.

Description

ASSESSING CARDIOPULMONARY RESUSCITATION BY AN IMPLANTABLEMEDICAL DEVICE

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 625,188, filed January 25, 2024, the entire contents of which are incorporated herein by reference.FIELD

[0002] The disclosure relates generally to medical device systems and, more particularly, medical device systems configured to assess cardiopulmonary resuscitation.BACKGROUND

[0003] Medical devices may be used to monitor physiological signals of a patient. For example, some medical devices are configured to sense cardiac electrogram (EGM) signals indicative of the electrical activity of the heart via electrodes. Some medical devices are additionally or alternatively configured to sense other signals, such as cardiac mechanical signals indicative of the mechanical activity of the heart via a motion or vibration sensor, such as an accelerometer.SUMMARY

[0004] In general, this disclosure is directed to techniques for assessing delivery of cardiopulmonary resuscitation (CPR) to a patient by an implantable medical device (IMD) implanted in the patient. The IMD may include sensors such as an accelerometer or other motion or vibration sensor, referred to as a cardiac mechanical sensor, and electrodes for sensing an electrocardiogram of the patient. In some examples, the IMD may be advantageously configured such that the assessment includes identification of a return of spontaneous circulation (ROSC) in the patient.

[0005] In some examples, the IMD determines cardiopulmonary resuscitation (CPR) is being administered to a patient. For example, IMD may determine CPR is being administered to a patient, based, at least in part, on an accelerometer signal and, in response to the determination that CPR is being administered to the patient, determines whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on the cardiac electrical signal. In response to a determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, the IMD determines whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold based on a cardiac mechanical signal sensed via a cardiac mechanical sensor during a period of time after thedetermination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

[0006] Using the techniques of this disclosure, the IMD may advantageously differentiate between a return of healthy pulsatile rhythm of the heart of the patient as opposed to a return of electrical rhythm alone (e.g., electromechanical dissociation). In this manner, IMD may be able to send a correct indication of the status of the heart of the patient undergoing CPR to a computing device to indicate to a person conducting CPR whether to stop CPR or continue with CPR. Sending a correct indication of the status of the heart of the patient undergoing CPR, especially in examples when a heart of a patient has electromechanical dissociation, may lead to improved performance of CPR that may lead to improved patient outcomes, such as reducing patient deaths due to CPR being stopped when a heart of a patient has electromechanical dissociation.

[0007] In one example, this disclosure describes an insertable cardiac monitor comprising: a plurality of electrodes to configured detect a cardiac electrical signal of a patient; a cardiac mechanical sensor configured to generate a cardiac mechanical signal; and processing circuitry configured to: determine cardiopulmonary resuscitation (CPR) is being administered to the patient; in response to the determination that CPR is being administered to the patient, determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on the cardiac electrical signal; and in response to a determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time based on a cardiac mechanical signal sensed via the cardiac mechanical sensor during the period of time.

[0008] In another example, this disclosure describes a medical system comprising: an implantable medical device comprising: a plurality of electrodes to configured detect a cardiac electrical signal of a patient; a cardiac mechanical sensor configured to generate a cardiac mechanical signal; and processing circuitry configured to: determine cardiopulmonary resuscitation (CPR) is being administered to the patient; in response to determination that CPR is being administered to the patient, determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on the cardiac electrical signal; and in response to a determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time based on a cardiac mechanical signal sensed via a cardiac mechanical sensor during the period of time.

[0009] In another example, this disclosure describes a method operating a medical system comprising an insertable cardiac monitor (ICM) to assess delivery of cardiopulmonary resuscitation (CPR), the method comprising: determining, by the ICM, CPR is being administered to a patient; in response to determination that CPR is being administered to the patient, determining, by the ICM, whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on a cardiac electrical signal sensed by a plurality of electrodes of the ICM; and in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, determining, by the ICM, whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time based on a cardiac mechanical signal sensed via a cardiac mechanical sensor of the ICM during the period of time.

[0010] The summary is intended to provide an overview of the subject matter described in this disclosure. It is not intended to provide an exclusive or exhaustive explanation of the systems, device, and methods described in detail within the accompanying drawings and description below. Further details of one or more examples of this disclosure are set forth in the accompanying drawings and in the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 illustrates the environment of an example medical system in conjunction with a patient.

[0012] FIG. 2 is a functional block diagram illustrating an example configuration of the implantable medical device (IMD) of the medical system of FIG. 1.

[0013] FIG. 3 is a conceptual side-view diagram illustrating an example configuration of the IMD of FIGS. 1 and 2.

[0014] FIG. 4A is a conceptual side-view diagram illustrating an example configuration of the IMD of FIGS. 1-3.

[0015] FIG. 4B is a conceptual side-view diagram illustrating an example configuration of the IMD of FIGS. 1-3.

[0016] FIG. 5 is a functional block diagram illustrating an example configuration of the external device of FIGS. 1-4.

[0017] FIG. 6 is a block diagram illustrating an example system that includes an access point, a network, external computing devices, such as a server, and one or more other computing devices, which may be coupled to the IMD and external device of FIGS. 1-5.

[0018] FIG. 7 is a flow diagram illustrating an example technique for operating a system to determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold.

[0019] FIGS. 8A-8B are flow diagrams illustrating an example technique for operating a medical system to monitor CPR and / or patient health during CPR.

[0020] Like reference characters denote like elements throughout the description and figures.DETAILED DESCRIPTION

[0021] A variety of types of medical devices sense cardiac EGMs. In some examples, EGMs may include electrocardiograms (ECGs or EKGs). Some IMDs sense and monitor cardiac EGMs. The electrodes used by IMDs to sense cardiac EGMs are typically integrated with a housing of the IMD and / or coupled to the IMD via one or more elongated leads. Some example IMDs include pacemakers and implantable cardioverter-defibrillators, which may be coupled to intravascular or extravascular leads, as well as pacemakers with housings configured for implantation within the heart, which may be leadless. Some IMDs that do not provide therapy, e.g., implantable patient monitors, sense cardiac EGMs. One example of such an IMD is the Reveal LINQ™ and LINQ II™ Insertable Cardiac Monitors (ICMs), available from Medtronic, Inc, which may be inserted subcutaneously. Such IMDs may facilitate relatively longer-term monitoring of patients during normal daily activities, and may periodically transmit collected data to a network service, such as the Medtronic Carelink™ Network.

[0022] A patient suffering an acute health event, such as sudden cardiac arrest (SCA), may need immediate application of CPR to support systemic delivery of oxygenated blood until the heart of the patient returns to a normal sinus rhythm, which includes a normal electrical rhythm and a corresponding normal mechanical rhythm of the heart. In some examples, a medical device may determine whether a heart returns to normal sinus rhythm during CPR e.g., return of spontaneous circulation (ROSC). In response to determining the heart returns to a normal sinus rhythm, the medical device may output an indication to stop CPR to reduce potential negative side effects from receiving CPR when a heart returns to a normal sinus rhythm, such as counteracting the normal heartbeat and / or initiating an arrhythmia.

[0023] However, on some occasions while receiving CPR, a heart may return to normal electrical rhythm but not return to a normal mechanical rhythm. In examples in which a heart of a patient returns to a normal electrical rhythm but does not return to a normal mechanical rhythm, a medical device using only electrical signals, such as ECG signals, to determine whether the heart returns to a normal sinus rhythm may incorrectly determine a heart returned to normal sinusrhythm because the electrical rhythm of the heart returned to normal even though the mechanical rhythm of the heart does not return to a normal mechanical rhythm. Based on the incorrect determination that the heart returned to normal sinus rhythm, the medical device may incorrectly output an indication that the heart returned to a normal sinus rhythm and to stop CPR, which may lead to serious health consequences for a patient whose heart returned to a healthy electrical rhythm but not a healthy mechanical rhythm, such organ damage or death.

[0024] The techniques described herein may provide an IMD, such as an ICM, pacemaker, or implantable cardioverter-defibrillator, to determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on the cardiac electrical signal and determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time after the determination that the heart of the patient satisfies the healthy electrical rhythm threshold. In some examples, in response to determining that the electrical rhythm of the heart of the patient satisfies a healthy electrical rhythm threshold and the mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold, the IMD may output a communication to a computing device to cause the computing device to display an indication to stop CPR. In some examples, in response to determining that the electrical rhythm of the heart of the patient satisfies a healthy electrical rhythm threshold and the mechanical rhythm of the heart of the patient does not satisfy a healthy mechanical rhythm threshold, the IMD may output a communication to a computing device to cause the computing device display an indication to continue or resume CPR.

[0025] In techniques described herein, the IMD may be able to differentiate between a return of healthy pulsatile rhythm of the heart of the patient as opposed to a return of electrical rhythm alone (e.g., electromechanical dissociation) based on cardiac electrical signals and cardiac mechanical signals and send a correct indication to a device to indicate to the person conducting CPR whether to stop CPR or continue with CPR.

[0026] FIG. 1 illustrates the environment of an example medical system 2 in conjunction with a patient 4, in accordance with one or more techniques of this disclosure. The example techniques may be used with an IMD 10, which may be in wireless communication with at least one of external device 12 and other devices not pictured in FIG. 1. In some examples, IMD 10 is implanted outside of a thoracic cavity of patient 4 (e.g., subcutaneously in the pectoral location illustrated in FIG. 1). IMD 10 may be positioned near the sternum near or just below the level of the heart of patient 4, e.g., at least partially within the cardiac silhouette. IMD 10 may include a plurality of electrodes (not shown in FIG. 1), which may act as cardiac electrical sensors, and one or more cardiac mechanical sensors configured to output signals that vary based on mechanicalactivity of the heart, such as motion or vibrations of the heart or blood. An accelerometer is an example of a cardiac mechanical sensor. In some examples, IMD 10 takes the form of the Reveal LINQ™ or LINQ II™ ICM, or another ICM similar to, e.g., a version or modification of, the Reveal LINQ™ or LINQ II™ ICMs.

[0027] External device 12 may be a computing device with a display viewable by the user and an interface for providing input to external device 12 (i.e., a user input mechanism). In some examples, external device 12 may be a notebook computer, tablet computer, workstation, one or more servers, cellular phone, personal digital assistant, or another computing device that may run an application that enables the computing device to interact with IMD 10. External device 12 is configured to communicate with IMD 10 and, optionally, another computing device (not illustrated in FIG. 1), via wireless communication. External device 12, for example, may communicate via near-field communication technologies (e.g., inductive coupling, NFC or other communication technologies operable at ranges less than 10-20 cm) and far-field communication technologies (e.g., RF telemetry according to the 802.11 or Bluetooth® specification sets, or other communication technologies operable at ranges greater than near-field communication technologies).

[0028] External device 12 may be used to configure operational parameters for IMD 10. External device 12 may be used to retrieve data from IMD 10. The retrieved data may include values of physiological parameters measured by IMD 10, indications of electrical rhythm of the heart of the patient and / or indications of mechanical rhythm of the heart of the patient detected by IMD 10, and physiological signals recorded by IMD 10. For example, external device 12 may retrieve ECG signals or other cardiac electrical signals, and accelerometer or other cardiac mechanical signals recorded by IMD 10. As discussed in greater detail below with respect to FIG. 5, one or more remote computing devices may interact with IMD 10 in a manner similar to external device 12, e.g., to program IMD 10 and / or retrieve data from IMD 10, via a network.

[0029] Processing circuitry of medical system 2, e.g., of IMD 10 and / or external device 12, may be configured to perform the example techniques of this disclosure for determining CPR is being administered, determining an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold and determining whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold. In some examples, the processing circuitry of medical system 2 determines whether CPR is being administered to patient 4 based, at least in part, on a cardiac mechanical signal sensed by a cardiac mechanical sensor of the IMD 10. The processing circuitry may activate the cardiac mechanical sensor and / or begin analyzingthe cardiac mechanical signal to detect CPR in response to detecting an acute medical event, such as potential lethal ventricular tachyarrhythmia or SC A.

[0030] Processing circuitry of medical system 2 may in response to a determination that CPR is being administered to patient 4, determine whether an electrical rhythm of a heart of the patient 4 satisfies a healthy electrical rhythm threshold based on an ECG or other cardiac electrical signal sensed via a plurality of electrodes of the IMD 10. Processing circuitry of medical system 2 may in response to the determination that the electrical rhythm of the heart of the patient 4 satisfies the healthy electrical rhythm threshold, determine whether a mechanical rhythm of the heart of the patient 4 satisfies a healthy mechanical rhythm threshold during a particular period of time based on the cardiac mechanical signal during the particular period of time. In some examples, the particular period of time may be up to 5 seconds after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold. In some examples, the particular period of time may be between 2 to 5 seconds after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

[0031] In some examples, in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, processing circuitry of medical system 2 may cause an indication to stop CPR to be output by external device 12 to facilitate determining whether the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold. Delivery of CPR may interfere with the ability of the processing circuitry to identify intrinsic mechanical cardiac activity in the mechanical cardiac signal sensed by IMD 10. In some examples, the indications output by external device 12 may include visual, audio, and / or tactile alerts.

[0032] In some examples, in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm and the determination that the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold, processing circuitry of medical system 2 may cause external device 12 to output an indication to stop CPR and / or an indication the heart of the patient 4 has returned to a healthy pulsatile rhythm. In some examples, the indications may include visual, audio, and / or tactile alerts.

[0033] In some examples, in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythm of the heart of the patient does not satisfy the healthy mechanical rhythm threshold, processing circuitry of medical system 2 may cause external device 12 to output an indication to continue CPR and / or an indication the heart of the patient 4 has not returned to ahealthy mechanical rhythm. In some examples, the indications may include visual, audio, and / or tactile alerts.

[0034] In some examples, processing circuitry of medical system 2 may determine, based on one or more of the electrical rhythm of the heart of the patient 4 or the mechanical rhythm of the heart of the patient 4, whether the heart of the patient 4 is condition to receive a shock, such as from an automated external defibrillator (AED). In some examples, in response to the determination that the heart of the patient is in condition to receive a shock, processing circuitry of medical system 2 may cause external device 12 to output an indication that patient 4 is in condition to receive a shock, such as from an AED.

[0035] FIG. 2 is a functional block diagram illustrating an example configuration of IMD 10 of FIG. 1 in accordance with one or more techniques described herein. In the illustrated example, IMD 10 includes electrodes 16A and 16B (collectively “electrodes 16”), antenna 26, processing circuitry 50, sensing circuitry 52, communication circuitry 54, storage device 56, switching circuitry 58, and sensors 62, including cardiac mechanical sensor(s) 62A. Although the illustrated example includes two electrodes 16, IMDs including or coupled to more than two electrodes 16 may implement the techniques of this disclosure in some examples. Electrodes 16 are an example of cardiac electrical sensors.

[0036] Processing circuitry 50 may include fixed function circuitry and / or programmable processing circuitry. Processing circuitry 50 may include any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or equivalent discrete or analog logic circuitry. In some examples, processing circuitry 50 may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to processing circuitry 50 herein may be embodied as software, firmware, hardware or any combination thereof.

[0037] Sensing circuitry 52 may be selectively coupled to electrodes 16 via switching circuitry 58, e.g., to select the electrodes 16 and polarity, referred to as the sensing vector, used to sense a cardiac EGM, as controlled by processing circuitry 50. Sensing circuitry 52 may sense signals from electrodes 16, e.g., to produce a cardiac EGM, in order to facilitate monitoring the electrical activity of the heart. Sensing circuitry 52 also may monitor signals from sensors 62, such as cardiac mechanical sensor(s) 62A. In some examples, cardiac mechanical sensor(s) 62A may be configured to generate cardiac mechanical signals based on motion or vibration of the heart or blood associated with cardiac contractions. Cardiac mechanical sensor(s) 62A may include one ormore accelerometers, microphones, pressure sensors, or optical sensors, and cardiac mechanical signals may include signals such as accelerometer signal(s), acoustic signal(s), pressure signal(s), and / or optical signal(s). In some examples, cardiac mechanical sensor(s) 62Amay include one or more accelerometers. In the example of a microphone or other cardiac mechanical sensor 62A, sensing circuitry 52 may receive raw cardiac vibrations monitored by cardiac mechanical sensor(s) 62A. Sensing circuitry 52 may include components / modules for converting the raw cardiac vibrations to a processed heart sound beat signal that can be analyzed to detect cardiac beats. In some examples, processing circuitry 50 may use signals received from sensors 62, including cardiac mechanical signal(s) by cardiac mechanical sensor(s) 62A, to determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold. In some examples, sensing circuitry 52 may include one or more filters and amplifiers for filtering and amplifying signals received from electrodes 16 and / or sensors 62.

[0038] Sensing circuitry 52 and / or processing circuitry 50 may be configured to detect cardiac depolarizations (e.g., P-waves of atrial depolarizations or R-waves of ventricular depolarizations) when the cardiac EGM amplitude crosses a sensing threshold. For cardiac depolarization detection, sensing circuitry 52 may include a rectifier, filter, amplifier, comparator, and / or analog-to-digital converter, in some examples. In some examples, sensing circuitry 52 may output an indication to processing circuitry 50 in response to sensing of a cardiac depolarization. In this manner, processing circuitry 50 may receive detected cardiac depolarization indicators corresponding to the occurrence of detected R-waves and P-waves in the respective chambers of heart. Processing circuitry 50 may use the indications of detected R-waves and P-waves for determining inter-depolarization intervals, heart rate, and detecting arrhythmias, such as tachyarrhythmias and asystole. In some examples, the cardiac electrical signal may be sensed during normal sinus rhythm to determine a healthy electrical rhythm threshold. In some examples, the cardiac mechanical signal, such as an accelerometer signal, may be sensed during normal sinus rhythm to determine a healthy mechanical rhythm threshold.

[0039] Sensing circuitry 52 may also provide one or more digitized cardiac electrical signals and / or one or more digitized cardiac mechanical signals to processing circuitry 50 for analysis, e.g., for use in determining whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold and determining whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold. In some examples, determining whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold, may additionally or alternatively include processing circuitry 50 configured to determine whether particular features of the mechanical rhythm, such as a magnitude of themechanical rhythm, satisfy a corresponding particular mechanical rhythm feature threshold, such as a magnitude of mechanical rhythm threshold. In some examples, processing circuitry 50 may store the digitized cardiac electrical signals in storage device 56. Processing circuitry 50 of IMD 10, and / or processing circuitry of another device that retrieves data from IMD 10, may analyze the cardiac electrical signals and / or heart motion signals to determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold and / or determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold. For example, a healthy mechanical rhythm threshold may be a count of positive crossings of a threshold over a period of time. In some examples, the healthy mechanical rhythm threshold may be selected to reduce or remove noise or other types of body motion from contributing to the count of positive crossings.

[0040] Communication circuitry 54 may include any suitable hardware, firmware, software or any combination thereof for communicating with another device, such as external device 12, another networked computing device, or another IMD or sensor. Under the control of processing circuitry 50, communication circuitry 54 may receive downlink telemetry from, as well as send uplink telemetry to external device 12 or another device with the aid of an internal or external antenna, e.g., antenna 26. In addition, processing circuitry 50 may communicate with a networked computing device via an external device (e.g., external device 12) and a computer network, such as the Medtronic CareLink® Network. Antenna 26 and communication circuitry 54 may be configured to transmit and / or receive signals via inductive coupling, electromagnetic coupling, Near Field Communication (NFC), Radio Frequency (RF) communication, Bluetooth, WiFi, or other proprietary or non-proprietary wireless communication schemes.

[0041] In some examples, storage device 56 includes computer-readable instructions that, when executed by processing circuitry 50, cause IMD 10 and processing circuitry 50 to perform various functions attributed to IMD 10 and processing circuitry 50 herein. Storage device 56 may include any volatile, non-volatile, magnetic, optical, or electrical media, such as a random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, or any other digital media. Storage device 56 may store, as examples, programmed values for one or more operational parameters of IMD 10 and / or data collected by IMD 10 for transmission to another device using communication circuitry 54. Data stored by storage device 56 and transmitted by communication circuitry 54 to one or more other devices may include digitized cardiac electrical signals and / or digitized cardiac mechanical signals, as examples.

[0042] FIG. 3 is a conceptual side-view diagram illustrating an example configuration of IMD 10 of FIGS. 1 and 2. In the example shown in FIG. 3, IMD 10 may include a leadless, subcutaneously-implantable monitoring device having a housing 15 and an insulative cover 76. Electrode 16A and electrode 16B may be formed or placed on an outer surface of cover 76. Circuitries 50-62, described above with respect to FIG. 2, may be formed or placed on an inner surface of cover 76, or within housing 15. In the illustrated example, antenna 26 is formed or placed on the inner surface of cover 76, but may be formed or placed on the outer surface in some examples. In some examples, one or more of sensors 62 may be formed or placed on the outer surface of cover 76. In some examples, insulative cover 76 may be positioned over an open housing 15 such that housing 15 and cover 76 enclose circuitries 50-62, and protect the circuitries from fluids such as body fluids.

[0043] Insulative cover 76 may be flipped onto a housing 15. When flipped and placed onto housing 15, the components of IMD 10 formed on the inner side of insulative cover 76 may be positioned in a gap 78 defined by housing 15. Electrodes 16 may be electrically connected to switching circuitry 58 through one or more vias (not shown) formed through insulative cover 76. Insulative cover 76 may be formed of sapphire (i.e. , corundum), glass, parylene, and / or any other suitable insulating material. Housing 15 may be formed from titanium or any other suitable material (e.g., a biocompatible material). Electrodes 16 may be formed from any of stainless steel, titanium, platinum, iridium, or alloys thereof. In addition, electrodes 16 may be coated with a material such as titanium nitride or fractal titanium nitride, although other suitable materials and coatings for such electrodes may be used.

[0044] FIG. 4A is a conceptual drawing illustrating an IMD 10A, which may be an example configuration of IMD 10 of FIGS. 1-3 as an ICM. In the example shown in FIG. 4A, IMD 10A may be embodied as a monitoring device having housing 15, proximal electrode 16A and distal electrode 16B, and sensor(s) 62. The sensor(s) 62 may be positioned at various locations on IMD 10A. Sensor(s) 62 may include one or more cardiac mechanical sensors 62A. Housing 15 may further comprise first major surface 14, second major surface 18, proximal end 20, and distal end 22. Housing 15 encloses electronic circuitry located inside the IMD 10A and protects the circuitry contained therein from body fluids. Electrical feedthroughs provide electrical connection of electrodes 16A and 16B.

[0045] In the example shown in FIG. 4A, IMD 10A is defined by a length a width W and thickness or depth D and is in the form of an elongated rectangular prism wherein the length L is much larger than the width W, which in turn is larger than the depth D. In one example, the geometry of the IMD 10A - in particular a width W greater than the depth D - is selected toallow IMD 10A to be inserted under the skin of the patient using a minimally invasive procedure and to remain in the desired orientation during and after insertion. For example, the device shown in FIG. 4A includes radial asymmetries (notably, the rectangular shape) along the longitudinal axis that maintains the device in the proper orientation following insertion. For example, the spacing between proximal electrode 64 and distal electrode 66 may range from 30 millimeters (mm) to 55mm, 35mm to 55mm, and from 40mm to 55mm and may be any range or individual spacing from 25mm to 60mm. In addition, IMD 10A may have a length L that ranges from 30mm to about 70mm. In other examples, the length L may range from 5mm to 60mm, 15mm to 50mm, 40mm to 60mm, 45mm to 60mm and may be any length or range of lengths between about 5mm and about 80mm. In addition, the width W of major surface 14 may range from 5mm to 15mm, 3mm to 10mm, and may be any single or range of widths between 3mm and 15mm. The thickness of depth D of IMD 10A may range from 2mm to 9mm. In other examples, the depth!) of IMD 10A may range from 2mm to 5mm, may range from 5mm to 15mm, and may be any single or range of depths from 2mm to 15mm. In addition, IMD 10A according to an example of the present disclosure is has a geometry and size designed for ease of implant and patient comfort. Examples of IMD 10A described in this disclosure may have a volume of three cubic centimeters (cm) or less, 1.5 cubic cm or less or any volume between three and 1.5 cubic cm.

[0046] In the example shown in FIG. 4 A, once inserted within the patient, the first major surface 14 faces outward, toward the skin of the patient while the second major surface 18 is located opposite the first major surface 14. In addition, in the example shown in FIG. 4A, proximal end 20 and distal end 22 are rounded to reduce discomfort and irritation to surrounding tissue once inserted under the skin of the patient. IMD 10 A, including instrument and method for inserting IMD 10 is described, for example, in U.S. Patent Publication No. 2014 / 0276928, incorporated herein by reference in its entirety.

[0047] Proximal electrode 16A and distal electrode 16B are used to sense cardiac signals, e.g. EGM signals, intra-thoracically or extra-thoracically, which may be sub-muscularly or subcutaneously. EGM signals may be stored in a memory of IMD 10A, and data may be transmitted via integrated antenna 30A to another medical device, which may be another implantable device or an external device, such as external device 12. In some example, electrodes 16A and 16B may additionally or alternatively be used for sensing any bio-potential signal of interest, which may be, for example, an ECG, EGM, EEG, EMG, or a nerve signal, from any implanted location.

[0048] In the example shown in FIG. 4 A, proximal electrode 16A is in close proximity to the proximal end 20 and distal electrode 16B is in close proximity to distal end 22. In this example, distal electrode 16B is not limited to a flattened, outward facing surface, but may extend from first major surface 14 around rounded edges 24 and / or end surface 25 and onto the second major surface 18 so that the electrode 16B has a three-dimensional curved configuration. In some examples, electrode 16B is an uninsulated portion of a metallic, e.g., titanium, part of housing 15.

[0049] In the example shown in FIG. 4 A, proximal electrode 16A is located on first major surface 14 and is substantially flat, and outward facing. However, in other examples proximal electrode 16A may utilize the three dimensional curved configuration of distal electrode 16B, providing a three dimensional proximal electrode (not shown in this example). Similarly, in other examples distal electrode 16B may utilize a substantially flat, outward facing electrode located on first major surface 14 similar to that shown with respect to proximal electrode 16A.

[0050] The various electrode configurations allow for configurations in which proximal electrode 16A and distal electrode 16B are located on both first major surface 14 and second major surface 18. In other configurations, such as that shown in FIG. 4A, only one of proximal electrode 16A and distal electrode 16B is located on both major surfaces 14 and 18, and in still other configurations both proximal electrode 16A and distal electrode 16B are located on one of the first major surface 14 or the second major surface 18 (e.g., proximal electrode 16A located on first major surface 14 while distal electrode 16B is located on second major surface 18). In another example, IMD 10A may include electrodes on both major surface 14 and 18 at or near the proximal and distal ends of the device, such that a total of four electrodes are included on IMD 10 A. Electrodes 16A and 16B may be formed of a plurality of different types of biocompatible conductive material, e.g., stainless steel, titanium, platinum, iridium, or alloys thereof, and may utilize one or more coatings such as titanium nitride or fractal titanium nitride.

[0051] In the example shown in FIG. 4A, proximal end 20 includes a header assembly 28 that includes one or more of proximal electrode 16A, integrated antenna 30A, anti -migration projections 32, and / or suture hole 34. Integrated antenna 30A is located on the same major surface (i.e., first major surface 14) as proximal electrode 16A and is also included as part of header assembly 28. Integrated antenna 30A allows IMD 10A to transmit and / or receive data. In other examples, integrated antenna 30A may be formed on the opposite major surface as proximal electrode 16 A, or may be incorporated within the housing 15 of IMD 10 A. In the example shown in FIG. 4A, anti -migration projections 32 are located adjacent to integrated antenna 30A and protrude away from first major surface 14 to prevent longitudinal movement of the device. In the example shown in FIG. 4 A, anti-migration projections 32 include a plurality(e.g., nine) small bumps or protrusions extending away from first major surface 14. As discussed above, in other examples anti-migration projections 32 may be located on the opposite major surface as proximal electrode 16A and / or integrated antenna 30A. In addition, in the example shown in FIG. 4A, header assembly 28 includes suture hole 34, which provides another means of securing IMD 10A to the patient to prevent movement following insertion. In the example shown, suture hole 34 is located adjacent to proximal electrode 16A. In one example, header assembly 28 is a molded header assembly made from a polymeric or plastic material, which may be integrated or separable from the main portion of IMD 1 OA.

[0052] FIG. 4B is a perspective drawing illustrating another IMD 10B, which may be another example configuration of IMD 10 from FIGS. 1-3. IMD 10B of FIG. 4B may be configured substantially similarly to IMD 10A of FIG. 4A, with differences between them discussed herein.

[0053] IMD 10B may include a leadless, subcutaneously -implantable monitoring device, e.g. an ICM. IMD 10B includes housing having a base 40 and an insulative cover 42. IMD 10B includes sensor(s) 62 that may be positioned at various locations on IMD 10B. Sensor(s) 62 may include one or more cardiac mechanical sensors 62A. Proximal electrode 16C and distal electrode 16D may be formed or placed on an outer surface of cover 42. Various circuitries and components of IMD 10B, e.g., described below with respect to FIG. 3, may be formed or placed on an inner surface of cover 42, or within base 40. In some examples, a battery or other power source of IMD 10B may be included within base 40. In the illustrated example, antenna 30B is formed or placed on the outer surface of cover 42, but may be formed or placed on the inner surface in some examples. In some examples, insulative cover 42 may be positioned over an open base 40 such that base 40 and cover 42 enclose the circuitries and other components and protect them from fluids such as body fluids.

[0054] Circuitries and components may be formed on the inner side of insulative cover 42, such as by using flip-chip technology. Insulative cover 42 may be flipped onto a base 40. When flipped and placed onto base 40, the components of IMD 10B formed on the inner side of insulative cover 42 may be positioned in a gap 44 defined by base 40. Electrodes 16C and 16D and antenna 30B may be electrically connected to circuitry formed on the inner side of insulative cover 42 through one or more vias (not shown) formed through insulative cover 42. Insulative cover 42 may be formed of sapphire (i.e., corundum), glass, parylene, and / or any other suitable insulating material. Base 40 may be formed from titanium or any other suitable material (e.g., a biocompatible material). Electrodes 16C and 16D may be formed from any of stainless steel, titanium, platinum, iridium, or alloys thereof. In addition, electrodes 16C and 16D may becoated with a material such as titanium nitride or fractal titanium nitride, although other suitable materials and coatings for such electrodes may be used.

[0055] In the example shown in FIG. 4B, the housing of IMD 10B defines a length I.. a width W and thickness or depth D and is in the form of an elongated rectangular prism wherein the length L is much larger than the width W, which in turn is larger than the depth Z), similar to IMD 10A of FIG. 4B. For example, the spacing between proximal electrode 64 and distal electrode 66 may range from 30mm to 50mm, from 35mm to 45mm, or be approximately 40mm. In addition, IMD 10B may have a length L that ranges from 30mm to about 70mm. In other examples, the length L may range from 5mm to 60mm, 40mm to 60mm, 45mm to 55mm, or be approximately 45mm. In addition, the width W may range from 3mm to 15mm, such as approximately 8mm. The thickness of depth D of IMD 10B may range from 2mm to 15mm, from 3 to 5mm, or be approximately 4mm. IMD 10B may have a volume of three cubic centimeters (cm) or less, or 1.5 cubic cm or less, such as approximately 1.4 cubic cm.

[0056] In the example shown in FIG. 4B, once inserted subcutaneously within the patient, outer surface of cover 42 faces outward, toward the skin of the patient. In addition, as shown in FIG. 4B, proximal end 46 and distal end 48 are rounded to reduce discomfort and irritation to surrounding tissue once inserted

[0057] FIG. 5 is a block diagram illustrating an example configuration of components of external device 12. In the example of FIG. 5, external device 12 includes processing circuitry 80, communication circuitry 82, storage device 84, and user interface 86.

[0058] Processing circuitry 80 may include one or more processors that are configured to implement functionality and / or process instructions for execution within external device 12. For example, processing circuitry 80 may be capable of processing instructions stored in storage device 84. Processing circuitry 80 may include, for example, microprocessors, DSPs, ASICs, FPGAs, or equivalent discrete or integrated logic circuitry, or a combination of any of the foregoing devices or circuitry. Accordingly, processing circuitry 80 may include any suitable structure, whether in hardware, software, firmware, or any combination thereof, to perform the functions ascribed herein to processing circuitry 80.

[0059] Communication circuitry 82 may include any suitable hardware, firmware, software or any combination thereof for communicating with another device, such as IMD 10. Under the control of processing circuitry 80, communication circuitry 82 may receive downlink telemetry from, as well as send uplink telemetry to, IMD 10, or another device. Communication circuitry 82 may be configured to transmit or receive signals via inductive coupling, electromagnetic coupling, Near Field Communication (NFC), Radio Frequency (RF) communication, Bluetooth,WiFi, or other proprietary or non-proprietary wireless communication schemes. Communication circuitry 82 may also be configured to communicate with devices other than IMD 10 via any of a variety of forms of wired and / or wireless communication and / or network protocols.

[0060] Storage device 84 may be configured to store information within external device 12 during operation. Storage device 84 may include a computer-readable storage medium or computer-readable storage device. In some examples, storage device 84 includes one or more of a short-term memory or a long-term memory. Storage device 84 may include, for example, RAM, DRAM, SRAM, magnetic discs, optical discs, flash memories, or forms of EPROM or EEPROM. In some examples, storage device 84 is used to store data indicative of instructions for execution by processing circuitry 80. Storage device 84 may be used by software or applications running on external device 12 to temporarily store information during program execution.

[0061] Data exchanged between external device 12 and IMD 10 may include operational parameters. External device 12 may transmit data including computer readable instructions which, when implemented by IMD 10, may control IMD 10 to change one or more operational parameters and / or export collected data. For example, processing circuitry 80 may transmit an instruction to IMD 10 which requests IMD 10 to export collected data (e.g., digitized cardiac electrical signals, and / or digitized cardiac mechanical signal(s) to external device 12. In turn, external device 12 may receive the collected data from IMD 10 and store the collected data in storage device 84. Processing circuitry 80 may implement any of the techniques described herein to analyze accelerometer signals, cardiac electrical signals, and / or cardiac mechanical signals received from IMD 10, e.g., to determine CPR is being administered, determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold and determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold.

[0062] A user, such as a person administering CPR or patient 4, may interact with external device 12 through user interface 86. User interface 86 includes a display (not shown), such as a liquid crystal display (LCD) or a light emitting diode (LED) display or other type of screen, with which processing circuitry 80 may present information related to IMD 10, e.g., cardiac electrical signals, cardiac mechanical signals, indications of whether electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold, indications of whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold, indications of whether the heart of the patient returns to a healthy pulsatile rhythm, and / or indications of whether to stop, resume, or continue CPR. In addition, user interface 86 may include an inputmechanism to receive input from the user. The input mechanisms may include, for example, any one or more of buttons, a keypad (e.g., an alphanumeric keypad), a peripheral pointing device, a touch screen, or another input mechanism that allows the user to navigate through user interfaces presented by processing circuitry 80 of external device 12 and provide input. In other examples, user interface 86 also includes audio circuitry for providing audible notifications, instructions or other sounds to the user, receiving voice commands from the user, or both.

[0063] FIG. 6 is a block diagram illustrating an example system that includes an access point 90, a network 92, external computing devices, such as a server 94, and one or more other computing devices 100A-100N (collectively, “computing devices 100”), which may be coupled to IMD 10 and external device 12 via network 92, in accordance with one or more techniques described herein. In this example, IMD 10 may use communication circuitry 54 to communicate with external device 12 via a first wireless connection, and to communicate with an access point 90 via a second wireless connection. In the example of FIG. 6, access point 90, external device 12, server 94, and computing devices 100 are interconnected and may communicate with each other through network 92.

[0064] Access point 90 may include a device that connects to network 92 via any of a variety of connections, such as telephone dial-up, digital subscriber line (DSL), or cable modem connections. In other examples, access point 90 may be coupled to network 92 through different forms of connections, including wired or wireless connections. In some examples, access point 90 may be a user device, such as a tablet or smartphone, that may be co-located with the patient. IMD 10 may be configured to transmit data, such as cardiac electrical signals, cardiac mechanical signals, indications of whether electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold, indications of whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold, indications of whether the heart of the patient returns to a healthy pulsatile rhythm, and / or indications of whether to stop, resume, or continue CPR to access point 90. Access point 90 may then communicate the retrieved data to server 94 via network 92.

[0065] In some cases, server 94 may be configured to provide a secure storage site for data that has been collected from IMD 10 and / or external device 12. In some cases, server 94 may assemble data in web pages or other documents for viewing by trained professionals, such as clinicians, via computing devices 100. One or more aspects of the illustrated system of FIG. 6 may be implemented with general network technology and functionality, which may be similar to that provided by the Medtronic CareLink™ Network. In some examples, server 94 may communicate with computing device 100 via network 92. For example, server 94 maycommunicate an analysis of data, such as determination of whether electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold and / or whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold, to computing device 100, external device 12, or any other computing device via network 92. For example, server 94 may communicate that a patient whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold and / or whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold to computing device 100, external device 12, or any other computing device via network 92.

[0066] In the example illustrated by FIG. 6, server 94 includes a storage device 96, e.g., to store data retrieved from IMD 10, and processing circuitry 98. Although not illustrated in FIG. 6 computing devices 100 may similarly include a storage device and processing circuitry.Processing circuitry 98 may include one or more processors that are configured to implement functionality and / or process instructions for execution within server 94. For example, processing circuitry 98 may be capable of processing instructions stored in memory 96. Processing circuitry 98 may include or be coupled to communication circuitry that may include any suitable hardware, firmware, software or any combination thereof for communicating with another device. In some examples, a description of processing circuitry 98 outputting a signal, such as a classification, may include processing circuitry 98 causing communication circuitry of server 94 to output the signal. Processing circuitry 98 may include, for example, microprocessors, DSPs, ASICs, FPGAs, or equivalent discrete or integrated logic circuitry, or a combination of any of the foregoing devices or circuitry. Accordingly, processing circuitry 98 may include any suitable structure, whether in hardware, software, firmware, or any combination thereof, to perform the functions ascribed herein to processing circuitry 98. Processing circuitry 98 of server 94 and / or the processing circuity of computing devices 100 may implement any of the techniques described herein to determine CPR is being administered, determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold and determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold.

[0067] Storage device 96 may include a computer-readable storage medium or computer- readable storage device. In some examples, memory 96 includes one or more of a short-term memory or a long-term memory. Storage device 96 may include, for example, RAM, DRAM, SRAM, magnetic discs, optical discs, flash memories, or forms of EPROM or EEPROM. In some examples, storage device 96 is used to store data indicative of instructions for execution by processing circuitry 98.

[0068] Although the techniques for determining CPR is being administered, determining whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold and determining whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold, are described herein primarily (e.g., with respect to FIG.) as being performed by processing circuitry 50 of IMD 10, such techniques may be performed, in whole or part, by processing circuitry of any one or more devices of system 2, such as processing circuitry 80 of external device 12, processing circuitry 98 of server 94, or processing circuitry of one or more computing devices 100.

[0069] FIG. 7 is a flow diagram illustrating an example technique for operation of a medical system 2 to determine an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on a cardiac electrical signal, determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold, and determine whether to out an indication to continue CPR or stop CPR. As indicated by FIG. 7, processing circuitry 50 may monitor one or more of a cardiac electrical signal or a cardiac mechanical signal in response to detecting an acute cardiac event (700). Processing circuitry 50 may determine whether CPR is being administered to the patient 4 based (710). For example, processing circuitry 50 may determine whether CPR is being administered to the patient 4 based, at least in part, on an accelerometer signal. In some examples, processing circuitry 50 may determine CPR is being administered to the patient 4 based, at least in part, on a value of an accelerometer signal indicating a force that is being applied to the patient 4 that satisfies a CPR threshold force. An IMD 10 may include an accelerometer configured to generate the accelerometer signal. In response to a determination that CPR is not being administered to the patient 4 (“NO”), processing circuitry 50 may return to feature (700).

[0070] In response to a determination that CPR is being administered to patient 4 (“YES”), processing circuitry 50 may determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on the cardiac electrical signal (720). In some examples, IMD 10 may include a plurality of electrodes 16 configured to detect an cardiac electrical signal of patient 4. In some examples, processing circuitry 50 may determine an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on detecting one or more of R- waves or P-waves in the cardiac electrical signal. In some examples, CPR being administered to patient 4 may interfere with the determination of whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold, such as causing artifacts on the cardiac electrical signal. In some examples, processing circuitry 50 may cause an indication to be output to a computing device, such as external device 12, to display an indicationto temporarily stop CPR for a stoppage period of time to facilitate determining whether the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold. In some examples, a stoppage period of time to temporarily stop CPR to facilitate determining of whether the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold may be up to ten seconds. In response to a determination that the electrical rhythm of a heart of the patient does not satisfy a healthy electrical rhythm threshold based on the cardiac electrical signal (“NO”), processing circuitry 50 may return to feature (720) to continue monitoring whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold.

[0071] In some examples, CPR being administered after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold may cause some cardiac mechanical sensors 62A to incorrectly determine the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold. In some examples, the healthy mechanical rhythm threshold may correspond to an amount of mechanical pulse, of the heart, such as an amount of heart contraction, to push blood out of respective chambers. Accordingly, in some examples, in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, processing circuitry 50 may cause an indication to be output to a computing device, such as external device 12, to display an indication to temporarily stop CPR for a stoppage period of time to facilitate determining of whether the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold. In some examples, a stoppage period of time to temporarily stop CPR to facilitate determining of whether the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold may be within five seconds after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold. In some examples, processing circuitry 50 may cause an indication to be output to a computing device, such as external device 12, to display an indication to temporarily stop CPR for a stoppage period of time in response to detecting an R-wave coming back in the cardiac electrical signal. The stoppage period of time may be within five seconds after the determination of the R- wave coming back in the cardiac electrical signal.

[0072] In response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold (“YES”), processing circuitry 50 may determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time based on a cardiac mechanical signal sensed via a cardiac mechanical sensor during the period of time (730). In some examples, the cardiac mechanicalsignal via a cardiac mechanical sensor 62A may include an accelerometer signal generated by the accelerometer. In some examples, the cardiac mechanical signal via a cardiac mechanical sensor 62A may include an acoustic signal sensed via a microphone. In some examples, the period of time is within five seconds after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold. In some examples, the period of time is between two to five seconds after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold. In some examples, the period of time may be less than two seconds. In some examples, the period of time may be greater than five seconds.

[0073] In response to determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and determination that the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold (“YES”), processing circuitry 50 may cause an indication to be output to a computing device, such as external device 12, to display an indication to stop CPR (740). For example, processing circuitry 50 may cause an indication to stop CPR to be displayed because processing circuitry 50 determines the heart of the patient 4 has returned to a healthy pulsatile rhythm based on the mechanical rhythm satisfying the healthy mechanical rhythm threshold and the electrical rhythm satisfying healthy electrical rhythm threshold.

[0074] In response to determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and determination that the mechanical rhythm of the heart of the patient does not satisfy the healthy mechanical rhythm threshold (“NO”), processing circuitry 50 may cause an indication to be output to a computing device, such as external device 12, to display an indication to continue CPR (750). In response to determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and determination that the mechanical rhythm of the heart of the patient does not satisfy the healthy mechanical rhythm threshold (“NO”), processing circuitry 50 may additionally or alternatively return to feature(s) (720) and / or (730) to continue monitoring whether the electrical rhythm of the heart satisfies a health electrical rhythm threshold or continue monitoring whether the mechanical rhythm of the heart of the patient satisfies a health mechanical rhythm threshold. For example, processing circuitry 50 may cause an indication to continue CPR to be displayed because processing circuitry 50 determines the heart of the patient 4 has not returned to a healthy pulsatile rhythm based on the mechanical rhythm not satisfying the healthy mechanical rhythm threshold even though the electrical rhythm satisfies healthy electrical rhythm threshold. In some examples, processing circuitry 50 may determine the heart of the patient 4 has electromechanicaldissociation based on the mechanical rhythm not satisfying the healthy mechanical rhythm threshold even though the electrical rhythm satisfies healthy electrical rhythm threshold. In some examples, in response to determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and determination that the mechanical rhythm of the heart of the patient doe not satisfy the healthy mechanical rhythm threshold (“NO”), may additionally and / or alternatively cause an indication to be output to a computing device, such as external device 12, to display an indication that patient has electromechanical dissociation.

[0075] FIGS. 8A-8B are a flow diagram illustrating an example technique for operation of a medical system 2 to monitor CPR and / or patient health during CPR. In some examples, sensors 62 may include sensors configured to sense respiration. In some examples, sensors 62 may sense respiration metrics, and / or metrics of congestion, perfusion, or edema, such as may be determined based on measurements of an impedance of the patient sensed by sensors 62 and / or electrodes 16.

[0076] As discussed in feature (710) of FIG. 7, processing circuitry 50 may detect CPR, such as determining whether CPR is being administered (800). Processing circuitry 50 may determine whether the compression rate of the CPR satisfies a compression rate threshold (805). For example, whether the compression rate of the CPR satisfies a threshold of being between 95 compressions per minute to 105 compression per minute.

[0077] In response to the compression rate of the CPR not satisfying a compression rate threshold (“NO”), processing circuitry 50 may cause communication circuitry 54 to send a message to cause computing device 12 to generate an indication to either increase or decrease CPR compression rate (807). In response to the compression rate of the CPR satisfying a compression rate threshold (“YES”), processing circuitry 50 may determine whether the compression depth of the CPR satisfies a compression depth threshold (810). For example, whether the compression depth of the CPR satisfies a threshold of being between 1.5 inches to 2.5 inches for adults.

[0078] In response to the compression rate of the CPR not satisfying a compression depth threshold (“NO”), processing circuitry 50 may cause communication circuitry 54 to send a message to cause computing device 12 to generate an indication to either increase or decrease CPR compression depth (812). In response to the compression depth of the CPR satisfying a compression depth threshold (“YES”), processing circuitry 50 may determine whether a chest recoil of the CPR satisfies a chest recoil threshold (815).

[0079] In response to the chest recoil of the CPR not satisfying a chest recoil threshold (“NO”), processing circuitry 50 may cause communication circuitry 54 to send a message to causecomputing device 12 to generate an indication to either increase chest recoil between compressions of CPR (817). In response to the chest recoil of the CPR satisfying a chest recoil threshold (“YES”), processing circuitry 50 may determine whether an amount of chest compressions detected satisfies a compression threshold (820). For example, the compression threshold may be between 25 and 35 compressions, such as 30 compressions.

[0080] In response to the amount of chest compressions detected not satisfying a compression threshold (“NO”), processing circuitry 50 may return to step (820) and continue to monitor an amount of compressions detected. In response to the amount of chest compressions detected satisfying a compression threshold (‘YES”), processing circuitry 50 may cause communication circuitry 54 to send a message to cause computing device 12 to generate an indication to provide ventilation breaths to patient 4 (825). For example, to provide up to 4 ventilation breaths or to provide up to 2 ventilation breaths. In response to sending a message to cause computing device 12 to generate an indication to provide ventilation breaths to patient 4, processing circuitry 50 determine whether tidal volume satisfies a tidal volume threshold (830).

[0081] In response to the tidal volume not satisfying a tidal volume threshold (“NO”), processing circuitry 50 may cause communication circuitry 54 to send a message to cause computing device 12 to generate an indication to either increase chest breath volume on next ventilation cycle (832). In response to the detected tidal volume satisfying a tidal volume threshold (“YES”), processing circuitry 50 may determine whether CPR duration satisfies a CPR duration threshold (835). For example, a CPR duration threshold may be between 1.5 minutes and 4 minutes. In some examples, a CPR duration threshold may be 2 minutes.

[0082] In response to the CPR duration not satisfying a CPR duration threshold (“NO”), processing circuitry 50 may return to step (835) and continue to monitor whether a CPR duration satisfies a CPR duration threshold. In response to the CPR duration satisfying a CPR duration threshold (“YES”), processing circuitry 50 may cause communication circuitry 54 to send a message to cause computing device 12 to generate an indication to check for a pulse of patient 4 (840). In some examples, in response to the CPR duration satisfying a CPR duration threshold (“YES”), processing circuitry 50 may automatically check for a pulse of patient 4, such as by determining whether an EGM signal is present with satisfactory rhythm that is associated with mechanical cardiac contraction and whether the mechanical cardiac contraction is sufficient to generate a pulse pressure waveform to perfuse the cardiac muscle.

[0083] In response to sending a message to cause computing device 12 to generate an indication to check for a pulse of patient 4, processing circuitry 50 determine whether a pulse is detected (845). In response to a determination that a pulse is not detected (“NO”), processing circuitry 50may return to step (800.) In response to a determination that a pulse is detected (“YES”), processing circuitry 50 may cause communication circuitry 54 to send a message to cause computing device 12 to generate an indication to stop CPR (850).

[0084] In response to sending a message to cause computing device 12 to generate an indication to stop CPR, processing circuitry 50 may determine whether spontaneous breathing is detected (855). In response to a determination that spontaneous breathing is not detected (“NO”), processing circuitry 50 may cause communication circuitry 54 to send a message to cause computing device 12 to generate an indication to provide one breath periodically, such as one breath every 5 to 6 seconds (857). In response to a determination that spontaneous breathing is detected (“YES”), processing circuitry 50 may cause communication circuitry 54 to send a message to cause computing device 12 to generate an indication to monitor patient 4 until an emergency medical technician arrives (860).

[0085] In some examples, the features of FIG. 7 may be performed at any point in FIGS. 8A-8B, such as, but limited to, after step 800, during step 820, during step 835, etc.

[0086] The techniques described in this disclosure may be implemented, at least in part, in hardware, software, firmware, or any combination thereof. For example, various aspects of the techniques may be implemented within one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic QRS circuitry, as well as any combinations of such components, embodied in external devices, such as physician or patient programmers, stimulators, or other devices. The terms “processor” and “processing circuitry” may generally refer to any of the foregoing logic circuitry, alone or in combination with other logic circuitry, or any other equivalent circuitry, and alone or in combination with other digital or analog circuitry.

[0087] For aspects implemented in software, at least some of the functionality ascribed to the systems and devices described in this disclosure may be embodied as instructions on a computer- readable storage medium such as RAM, DRAM, SRAM, magnetic discs, optical discs, flash memories, or forms of EPROM or EEPROM. The instructions may be executed to support one or more aspects of the functionality described in this disclosure.

[0088] In addition, in some aspects, the functionality described herein may be provided within dedicated hardware and / or software modules. Depiction of different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be realized by separate hardware or software components. Rather, functionality associated with one or more modules or units may be performed by separate hardware or software components, or integrated within common or separate hardware or software components. Also, the techniques could be fully implemented in one or more circuits or logicelements. The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including an IMD, an external programmer, a combination of an IMD and external programmer, an integrated circuit (IC) or a set of ICs, and / or discrete electrical circuitry, residing in an IMD and / or external programmer.

[0089] The following examples are illustrative of the techniques described herein.

[0090] Example 1 : An insertable cardiac monitor includes a plurality of electrodes to configured detect a cardiac electrical signal of a patient; a cardiac mechanical sensor configured to generate a cardiac mechanical signal; and processing circuitry configured to: determine cardiopulmonary resuscitation (CPR) is being administered to the patient; in response to the determination that CPR is being administered to the patient, determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on the cardiac electrical signal; and in response to a determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time based on a cardiac mechanical signal sensed via the cardiac mechanical sensor during the period of time.

[0091] Example 2: The insertable cardiac monitor of example 1, wherein the period of time is between two to five seconds after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

[0092] Example 3: The insertable cardiac monitor of any of examples 1-2, further includes in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR for a stoppage period of time to facilitate determining of whether the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold.

[0093] Example 4: The insertable cardiac monitor of any of examples 1-3, further includes in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold, cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR.

[0094] Example 5: The insertable cardiac monitor of any of examples 1-3, further includes in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythm of the heart of the patient does not satisfy the healthy mechanical rhythm threshold, cause the communicationcircuitry to send a message to a computing device to cause the computing device to display an indication to continue CPR.

[0095] Example 6: The insertable cardiac monitor of any of examples 1-5, further includes cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR for an electrical rhythm stoppage period of time to facilitate determining of whether the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

[0096] Example 7: The insertable cardiac monitor of any of examples 1-6, wherein the processing circuitry is further configured to: determine an acute cardiac event occurred in the patient based, at least in part, on one or more of the cardiac electrical signal or the cardiac mechanical signal; and determine whether CPR is being administered to the patient in response to the determination that an acute cardiac event occurred in the patient.

[0097] Example 8: The insertable cardiac monitor of any of examples 1-7, wherein the cardiac mechanical sensor is a microphone and the cardiac mechanical signal is an acoustic signal sensed via the microphone.

[0098] Example 9: The insertable cardiac monitor of any of examples 1-8, wherein the cardiac electrical signal is an electrocardiogram (ECG) signal.

[0099] Example 10: The insertable cardiac monitor of any of examples 1-7, wherein the cardiac mechanical sensor is an accelerometer and the cardiac mechanical signal is an accelerometer signal sensed via the accelerometer.

[0100] Example 11: The insertable cardiac monitor of any of examples 1-10, wherein processing circuitry is configured to determine CPR is being administered to the patient based on an accelerometer signal.

[0101] Example 12: The insertable cardiac monitor of any of examples 3-6, wherein the communication circuitry is configured to send a message to a computing device to cause the computing device to display an indication of the effectiveness of at least one of chest compressions or rescue breathing of the CPR being administered.

[0102] Example 13: A medical system includes an implantable medical device includes a plurality of electrodes to configured detect a cardiac electrical signal of a patient; a cardiac mechanical sensor configured to generate a cardiac mechanical signal; and processing circuitry configured to: determine cardiopulmonary resuscitation (CPR) is being administered to the patient; in response to determination that CPR is being administered to the patient, determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on the cardiac electrical signal; and in response to a determination that theelectrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time based on a cardiac mechanical signal sensed via a cardiac mechanical sensor during the period of time.

[0103] Example 14: The medical system of example 13, wherein the period of time is between two to five seconds after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

[0104] Example 15: The medical system of any of examples 13-14, further includes in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR for a stoppage period of time to facilitate determining of whether the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold.

[0105] Example 16: The medical system of any of examples 13-15, further includes in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold, cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR.

[0106] Example 17: The medical system of any of examples 13-15, further includes in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythm of the heart of the patient does not satisfy the healthy mechanical rhythm threshold, cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to continue CPR.

[0107] Example 18: The medical system of any of examples 13-17, further includes cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR for an electrical rhythm stoppage period of time to facilitate determining of whether the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

[0108] Example 19: The medical system of any of examples 13-18, wherein the cardiac electrical signal is an electrocardiogram (ECG) signal.

[0109] Example 20: The medical system of any of examples 13-19, wherein processing circuitry is configured to determine CPR is being administered to the patient based on an accelerometer signal.

[0110] Example 21: The medical system of any of examples 13-20, wherein the cardiac mechanical sensor is a microphone and the cardiac mechanical signal is an acoustic signal sensed via the microphone.

[0111] Example 22: The medical system of any of examples 13-20, wherein the cardiac mechanical sensor is an accelerometer and the cardiac mechanical signal is an accelerometer signal sensed via the accelerometer.

[0112] Example 23: The medical system of any of examples 15-18, wherein the communication circuitry is configured to send a message to the computing device to cause the computing device to display an indication of the effectiveness of at least one of chest compressions or rescue breathing of the CPR being administered.

[0113] Example 24: A method operating a medical system includes determining, by the ICM, CPR is being administered to a patient; in response to determination that CPR is being administered to the patient, determining, by the ICM, whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on a cardiac electrical signal sensed by a plurality of electrodes of the ICM; and in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, determining, by the ICM, whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time based on a cardiac mechanical signal sensed via a cardiac mechanical sensor of the ICM during the period of time.

[0114] Example 25: The method of example 24, wherein the period of time is between two to five seconds after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

[0115] Example 26: The method of any of examples 24-25, wherein the method further comprises: in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, causing, by processing circuitry of the ICM, communication circuitry of the ICM to send a message to a computing device to cause the computing device to display an indication to stop CPR for a stoppage period of time to facilitate determining of whether the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold.

[0116] Example 27: The method of any of examples 24-26, wherein the method further comprises: in response to the determination that the electrical rhythm of the heart of the patientsatisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold, causing, by processing circuitry of the ICM, communication circuitry of the ICM to send a message to a computing device to cause the computing device to display an indication to stop CPR.

[0117] Example 28: The method of any of examples 24-26, wherein the method further comprises: in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythm of the heart of the patient does not satisfy the healthy mechanical rhythm threshold, causing, by processing circuitry of the ICM, communication circuitry of the ICM to send a message to a computing device to cause the computing device to display an indication to continue CPR.

[0118] Example 29: The medical system of any of examples 24-28, wherein the method further comprises: causing, by processing circuitry of the ICM, communication circuitry of the ICM to send a message to a computing device to cause the computing device to display an indication to stop CPR for an electrical rhythm stoppage period of time to facilitate determining of whether the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

[0119] Example 30: The method of any of examples 25-29, wherein the cardiac electrical signal is an electrocardiogram (ECG) signal.

[0120] Example 31: The method of any of examples 25-30, the method further comprising determining CPR is being administered to the patient based on an accelerometer signal.

[0121] Example 32: The method of any of examples 25-31, the method further includes determining an acute cardiac event occurred in the patient based, at least in part, on one or more of the cardiac electrical signal or the cardiac mechanical signal; and determining whether CPR is being administered to the patient in response to the determination that an acute cardiac event occurred in the patient.

[0122] Example 33: The method of any of examples 25-32, wherein the cardiac mechanical sensor is a microphone and the cardiac mechanical signal is an acoustic signal sensed via the microphone.

[0123] Example 34: The method of any of examples 25-32, wherein the cardiac mechanical sensor is an accelerometer and the cardiac mechanical signal is an accelerometer signal sensed via the accelerometer.

[0124] Example 35: The method of any of examples 27-30, the method further includes causing, by processing circuitry of the ICM, the communication circuitry to send a message to the computing device to cause the computing device to display an indication of the effectiveness of at least one of chest compressions or rescue breathing of the CPR being administered.

[0125] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

CLAIMSWhat is claimed is:

1. An insertable cardiac monitor comprising: a plurality of electrodes to configured detect a cardiac electrical signal of a patient; a cardiac mechanical sensor configured to generate a cardiac mechanical signal; and processing circuitry configured to: determine cardiopulmonary resuscitation (CPR) is being administered to the patient; in response to the determination that CPR is being administered to the patient, determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on the cardiac electrical signal; and in response to a determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time based on a cardiac mechanical signal sensed via the cardiac mechanical sensor during the period of time.

2. The insertable cardiac monitor of claim 1, wherein the period of time is between two to five seconds after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

3. The insertable cardiac monitor of any of claims 1-2, further comprising communication circuitry, wherein the processing circuitry is further configured to: in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR for a stoppage period of time to facilitate determining of whether the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold.

4. The insertable cardiac monitor of any of claims 1-3, further comprising communication circuitry, wherein the processing circuitry is further configured to: in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythmof the heart of the patient satisfies the healthy mechanical rhythm threshold, cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR.

5. The insertable cardiac monitor of any of claims 1-3, further comprising communication circuitry, wherein the processing circuitry is further configured to: in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythm of the heart of the patient does not satisfy the healthy mechanical rhythm threshold, cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to continue CPR.

6. The insertable cardiac monitor of any of claims 1-5, further comprising communication circuitry, wherein the processing circuitry is further configured to: cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR for an electrical rhythm stoppage period of time to facilitate determining of whether the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

7. The insertable cardiac monitor of any of claims 1-6, wherein the processing circuitry is further configured to: determine an acute cardiac event occurred in the patient based, at least in part, on one or more of the cardiac electrical signal or the cardiac mechanical signal; and determine whether CPR is being administered to the patient in response to the determination that an acute cardiac event occurred in the patient.

8. The insertable cardiac monitor of any of claims 3-6, wherein the communication circuitry is configured to send a message to a computing device to cause the computing device to display an indication of the effectiveness of at least one of chest compressions or rescue breathing of the CPR being administered.

9. A medical system comprising: an implantable medical device comprising:a plurality of electrodes to configured detect a cardiac electrical signal of a patient; a cardiac mechanical sensor configured to generate a cardiac mechanical signal; and processing circuitry configured to: determine cardiopulmonary resuscitation (CPR) is being administered to the patient; in response to determination that CPR is being administered to the patient, determine whether an electrical rhythm of a heart of the patient satisfies a healthy electrical rhythm threshold based on the cardiac electrical signal; and in response to a determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, determine whether a mechanical rhythm of the heart of the patient satisfies a healthy mechanical rhythm threshold during a period of time based on a cardiac mechanical signal sensed via a cardiac mechanical sensor during the period of time.

10. The medical system of claim 9, wherein the period of time is between two to five seconds after the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

11. The medical system of any of claims 9-10, further comprising communication circuitry, wherein the processing circuitry is further configured to: in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold, cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR for a stoppage period of time to facilitate determining of whether the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold.

12. The medical system of any of claims 9-11, further comprising communication circuitry, wherein the processing circuitry is further configured to: in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythm of the heart of the patient satisfies the healthy mechanical rhythm threshold, cause thecommunication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR.

13. The medical system of any of claims 9-11, further comprising communication circuitry, wherein the processing circuitry is further configured to: in response to the determination that the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold and the determination that the mechanical rhythm of the heart of the patient does not satisfy the healthy mechanical rhythm threshold, cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to continue CPR.

14. The medical system of any of claims 9-13, further comprising communication circuitry, wherein the processing circuitry is further configured to: cause the communication circuitry to send a message to a computing device to cause the computing device to display an indication to stop CPR for an electrical rhythm stoppage period of time to facilitate determining of whether the electrical rhythm of the heart of the patient satisfies the healthy electrical rhythm threshold.

15. The medical system of any of claims 11-14, wherein the communication circuitry is configured to send a message to the computing device to cause the computing device to display an indication of the effectiveness of at least one of chest compressions or rescue breathing of the CPR being administered.

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