Miniature 3-lead mobile cardiac monitoring device

Abstract

A compact, three-lead mobile cardiac monitoring device for remote detection and / or diagnosis of cardiac events (e.g., acute myocardial infarction). The device includes two integrated hand electrodes and two chest electrodes mounted on two swivel arms that can be retracted into a compartment, enabling a compact size when the device is not in use. Also described herein are the system including these devices and the method of using them.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This patent application claims priority to U.S. Provisional Patent Application No. 62,847,308, filed May 13, 2019, and entitled “COMPACT MOBILE THREE-LEAD CARDIAC MONITORING DEVICE.”

[0002] (Incorporated by reference) All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

[0003] The methods and devices (e.g., systems, devices, etc.) described herein relate generally to electrocardiography. Described herein are devices and systems including small, handheld electrocardiogram (ECG) devices with retractable electrodes, and methods of using the same. In addition to recording ECG signals, these devices may process and transmit the ECG data to a handheld processor (e.g., a smartphone) and / or transmit the ECG data to a remote computer server for automated analysis and generation of diagnostic information that is sent back to the patient and / or sent to a medical professional. [Background technology]

[0004] Handheld ECG devices have been proposed. Such devices may be used by a patient (or medical professional) to record an ECG. However, to date, despite the potential advantages of such handheld devices, none have been widely used. This is due in part to the relatively large size, weight, and complex form factor of the proposed devices, which may include a handle and / or several cables. Additionally, many of such proposed devices have components that protrude from the device's profile when the device is not in use. Thus, there is a need for a handheld ECG that is capable of diagnosing a wide range of cardiac conditions while at the same time being small and easy to carry in a pocket or purse. Summary of the Invention [Problem to be solved by the invention]

[0005] Described herein are devices and methods that can address these problems. [Means for solving the problem]

[0006] The present invention relates to methods and devices, including small, lightweight, handheld ECG devices that can be easily carried and handled, including slipping into a pocket or purse. These devices are also ergonomic and easy to use, and capable of detecting a variety of cardiac conditions.

[0007] For example, described herein are credit card-like three-lead mobile cardiac monitoring devices for automatic recording of ECG. These devices are small, e.g., having a maximum thickness in a stored configuration of 2 cm or less (e.g., 1.9 cm or less, 1.8 cm or less, 1.7 cm or less, 1.6 cm or less, 1.5 cm or less, 1.4 cm or less, 1.3 cm or less, 1.2 cm or less, 1.1 cm or less, 1.0 cm or less, etc., including between 0.2 and 2.2 cm, between 0.2 and 2 cm, etc.). These devices are easy to handle and lightweight, easy to carry when not in use, and effective in detecting and diagnosing various cardiac conditions.

[0008] Thus, described herein are small, handheld ECG devices for recording and analyzing a patient's ECG without the use of cables. In some variations, they are credit card shaped (e.g., relatively thin and having a small diameter, e.g., having a maximum diameter of 12 cm or less (e.g., 11 cm or less, 10 cm or less, 9 cm or less, 8 cm or less, etc.)). These devices are highly mobile and can be configured for three-lead cardiac monitoring. The devices can include two electrodes for contacting the patient's chest and two electrodes for contacting the patient's fingers. The finger electrodes can be integrated into the front and / or sides of the device.

[0009] For example, four electrodes may be provided on the front and on two pivoting arms so that when the device is in the working position it can be held by a user's hands in a default orientation, and when held on the user's chest it records an orthogonal three-lead cardiac signal. An example of orthogonal lead recording is described in WO 2016 / 164888, which is incorporated herein by reference in its entirety.

[0010] In some variations, the device may be used in conjunction with or as part of a system configured for automatic or semi-automatic detection and diagnosis of acute myocardial infarction (AMI), atrial fibrillation, or other cardiac disease by acquiring substantially orthogonal leads from four integral electrodes that may be operated by a patient experiencing symptoms associated with an ongoing cardiac event and used to generate cardiac vectors that may be further used, for example, as part of a difference vector analysis of the cardiac vectors to detect one or more cardiac events. The cardiac difference vectors may be used, along with additional information including risk factor information and current symptom information, to further define the patient's emergency condition, for example to determine or confirm that the patient is experiencing a cardiac event.

[0011] Three orthogonal leads can be formed by using various electrode configurations with or without a centrally-pointed resistive network, with the resulting three leads generally being non-coplanar and as close to orthogonal as possible.

[0012] In some variations, the device (system, apparatus, etc.) may perform a reference recording of a first set of three orthogonal leads that may be stored in a memory (e.g., resistors). During a diagnostic recording, a second set of three orthogonal leads may be acquired and a difference signal between the two sets may be determined. Cardiographic signals represented by parameters of the ECG reference recording, the diagnostic recording, and the difference signal may be transmitted to an internal processor and / or wirelessly transmitted to a remote processor for processing. The device may also be configured to communicate diagnostic information to the patient by the device. The received diagnostic information may be presented to the user in the form of a characteristic sound, voice, graphic, or text.

[0013] For example, the device may include a plate-like housing having a front and / or a back. The housing may have a size and shape similar to a typical credit card. The housing may include two pivoting arms disposed on each side thereof, with each arm including an electrode capable of acquiring signals related to the patient's chest. The arms may be stored in respective compartments provided in the housing when not in use, e.g., during transport, such that they fit flush with an outer surface of the housing (e.g., in a compact configuration).

[0014] Additionally, the arms may include locking means for locking the arms to the housing when held in the stored position such that the arms are locked relative to the housing in a spring biased manner. The arms may include a bias (e.g., elastic, spring, etc.) for spring biasing the arms for release from the stored position. Alternatively, the arms may be biased to be held in a folded configuration. The bias may be released when the arms are deployed. The arms may be locked in a folded configuration (and biased to expand when unlocked) and / or locked in an extended configuration (and in some variations biased to fold into a compact configuration when unlocked). For example, a respective torsion spring may be provided in association with each of the arms such that an end portion of each torsion spring is supported by the arm and the housing, respectively.

[0015] The pivoting arms are compact in size when retracted into their respective compartments. When deployed, the arms extend into an active position forming an angle between them, thus allowing them to conform to the patient's chest morphology and providing good contact between the associated chest electrodes and the patient's skin. The distance between the chest electrodes in the deployed (e.g., active) position may be greater than 10 cm. In some variations, in the deployed configuration, the arms and associated electrodes may extend beyond the edge of the housing.

[0016] In some variations, the device may include two hand electrodes disposed on the front and / or sides of the housing. For example, the two electrodes may be disposed on the front of the housing such that the patient's fingers rest on the two electrodes when the chest electrodes are in place on the patient's chest. This may be advantageous as it allows the patient to fully grasp and hold the device securely for ECG recording.

[0017] In some variations, these two "hand" electrodes are located on corresponding chamfers on the front longitudinal edges of the housing, allowing easy access by the patient's fingers along with the pressure required to hold the housing on the chest. The hand electrodes are offset relative to the lateral centerline of the front surface so that they are closer to the patient's left arm during recording, to prevent the patient from switching their fingers between the left and right hands.

[0018] In some variations, the hand electrodes are disposed in a recessed portion of the front face of the housing, allowing the hand electrodes to fit flush with the front face. In some variations, the device includes two finger electrodes and two chest electrodes, as well as a ground electrode disposed on the front face of the housing for pressing by the fingers in the same manner as the hand recording electrodes.

[0019] For example, described herein is a three-lead mobile cardiac monitoring device (e.g., a "mini" device) having a first compact undeployed configuration and a second deployed configuration. The device includes a housing having a front and a back, two chest electrodes, two finger electrodes, and two retractable arms pivotally attached to the housing at opposite ends, where the two finger electrodes are disposed on a front or leading edge of the housing and the two chest electrodes are disposed on the retractable arms that retract flush with the back in the undeployed configuration and extend at an angle to the back in the deployed configuration.

[0020] Also described herein are methods of using these three-lead mobile cardiac monitoring devices having a first, non-deployed configuration and a second, deployed configuration as described herein. For example, described herein is a method of automatically assessing a patient's risk of an acute cardiac event, the method including receiving risk assessment information from a patient including risk factors, the risk assessment information being received by a processor, storing a pre-existing risk score based on the risk assessment information, receiving a sample electrocardiogram (ECG) from the patient, the sample ECG being automatically recorded by the patient using the three-lead mobile cardiac monitoring device having a first, non-deployed configuration and a second, deployed configuration, receiving a current symptom indication from the patient, determining in the processor an ECG risk score from the sample ECG and the reference ECG and a chest pain risk score based on the current symptom indication, determining a post-test risk score using the ECG risk score, the pre-existing risk score, and the chest pain risk score, and presenting a diagnostic report and patient action instructions to the patient based on the post-test risk score.

[0021] Any of these methods may include deploying the three-lead mobile cardiac monitoring device from a first compact, undeployed configuration to a second deployed configuration. For example, deploying the device may include unlocking the legs to automatically extend from a storage compartment. Deploying may include holding the legs against the chest. The electrode and / or leg configurations described herein may provide enhanced contact, comfort, and accuracy. The body of the device may be held away from the chest, while the electrodes may be adapted to this.

[0022] These methods include receiving a baseline ECG from the patient at the processor 24 hours or more prior to receiving the sample ECG, the patient obtaining the baseline ECG using a handheld device. The risk factors may include age, total cholesterol, HDL, systolic blood pressure, diabetes mellitus status, and current smoking status. In some variations, the existing risk score based on the risk assessment information includes a weighted sum of the risk factors by calculation.

[0023] Receiving the sample ECG includes the patient using a three-lead mobile cardiac monitoring device having a first compact undeployed configuration and a second deployed configuration, the handheld device having at least four electrodes for acquiring the substantially orthogonal three leads. Receiving the current symptom indication may include selecting the current symptom indication from a predefined list of symptoms selectable on the handheld device. In any of these methods, the selection may include selecting the current symptom indication from a user interface of the handheld device. Determining the ECG risk score may include indicating a risk that is high (H), medium (I), or low (L). Determining the chest pain risk score may include indicating a risk that is high (H), medium (I), or low (L). For example, determining the post-test risk score may include applying a look-up table indexed by the ECG risk score, the chest pain risk score, and the existing risk score. Prior to determining the ECG risk score, the steps of receiving the sample ECG and the current symptom indication may be repeated. The novel features of the invention are set forth with particularity in the following claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which: [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 shows a front axonometric view of the device with the arms in the deployed position when the device is ready for use for ECG recording. [Diagram 2]FIG. 2 shows a front axonometric view of the device in a transport position with the arms retracted into a compartment of the housing, as when the device is not in operation. [Diagram 3] FIG. 1 is a rear axonometric view of the device with the arms in the retracted position. [Figure 4] FIG. 13 is a detailed view showing an axonometric view of the arms and compartments from the rear in the deployed position. [Diagram 5] FIG. 5 shows a longitudinal section axonometric view of FIG. [Figure 6A] ~ [Figure 6B] 1 illustrates a prototype signal acquisition device for recording ECG. [Figure 7] 1 is an example of a patient using a signal collection device as described herein. [Figure 8] 1 illustrates a schematic of the operation of a system using a signal collection device. [Figure 9A] 1 illustrates one variation of a schematic configuration of a diagnostic system for detection of cardiac disease, such as AMI, including a three-lead mobile cardiac monitoring device having a first compact undeployed configuration and a second deployed configuration as described herein. [Figure 9B] FIG. 1 is another schematic diagram of a diagnostic system including a three-lead mobile cardiac monitoring device having a first compact, undeployed configuration and a second deployed configuration, with a processor located remotely from the handheld device. [Figure 10] FIG. 1 shows a simplified electrical scheme for determining the central point CP by connecting electrodes on both hands through a simple resistive network comprising two resistors in a three-lead mobile cardiac monitoring device having a first compact undeployed configuration and a second deployed configuration as described herein. [Figure 11A] A schematic configuration of three cardiac leads measured at the torso is shown, with one lead using the center point as the reference electrode. [Figure 11B] The electrical circuit of three cardiac leads is shown, with one lead using the central point as the reference electrode. [Figure 11C] A schematic configuration of three cardiac leads measured at the torso is shown, with two leads using the center point as the reference electrode. [Figure 11D]An electrical circuit of three cardiac leads, two of which use the center as the reference electrode. [Figure 11E] ~ [Figure 11G] FIG. 1 shows schematic diagrams of three possible configurations for measuring three leads among two chest electrodes and two hand electrodes. [Figure 12] 1 shows a flowchart of a method for detecting AMI including a three-lead mobile cardiac monitoring device having a first compact undeployed configuration and a second deployed configuration as described herein. [Figure 13] 1 is a table illustrating a parameter questionnaire list that may be used to estimate Chest Pain Risk (CPR) as described herein. [Figure 14] 1 is a table illustrating an example of an AMI risk assessment method described herein. [Figure 15] 1 is a process flow illustrating one method of displaying risk and treatment advice to a patient as described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Described herein is equipment including devices and systems that may include a small (e.g., credit card size and shape) three-lead mobile cardiac monitoring device for user placement on the chest. These devices may have four recording electrodes arranged to allow recording of three orthogonal ECG lead signals. These handheld devices may include two chest recording electrodes disposed on a pivotable and / or retractable arm that is hinged to the housing of the device. The device may include two non-chest electrodes disposed on the front and / or sides (including chamfered sides) of the housing that may be used to collect cardiac signals from the fingers of the left and right hands. The device may also include an optional fifth electrode disposed on the front of the device that may be used as a ground electrode, so that the device includes four recording electrodes and one ground electrode.

[0026] The devices described herein can be used, for example, in the automated remote diagnosis of cardiac conditions such as acute myocardial infarction (AMI), atrial fibrillation (AFiB), and other such cases of assumed cardiac events. The device is configured to measure three substantially orthogonal cardiac leads and store ECG recording components (e.g., electrodes, circuitry, controllers) for recording the patient's ECG signal along with most of the diagnostic information present in a conventional 12-lead ECG.

[0027] Figures 1 through 4 show an example of the device described herein (a credit card-shaped handheld ECG device). The device can include a plate-shaped housing that is relatively thin compared to its length and width. The shape of the housing can be similar to that of a typical credit card, so the base of the housing has approximately the same length and width as a standard credit card, e.g., between about 6 and 10 cm (e.g., between about 7 and 9 cm, between about 7.5 and 9 cm, between about 8.2 and 8.8 cm, about 8.6 cm) in length and between about 4 cm and about 6.5 cm (e.g., about 5.4 cm, between about 4.5 and 6.5 cm, between about 5 and about 6 cm, between about 5.2 and 5.8 cm, etc.). On average, the device housing can be thinner than 10 mm (e.g., about 8 mm or less, about 7 mm or less, about 6 mm or less, about 5 mm or less, about 4 mm or less, etc.).

[0028] In some variations, the housing 10 has a surface 12 (e.g., the front surface) with a hand electrode 14 for collecting signals from the patient's hand and two pivoting arms 16 hinged to the housing 10, each arm having a chest electrode 18 for collecting signals from the patient's chest. The housing 10 can be made of plastic or metal.

[0029] Additionally, the housing 10 has a surface 20 (e.g., the back surface) that is concave such that two substantially cylindrical sections 22 that are opposite each other are symmetrically arranged about the vertical centerline of the back surface 20, and each section 22 is formed adjacent to the short edge 23 of the front surface.

[0030] Each compartment has a bottom 24, two side walls 26, and a front wall 28. Unlike the side walls 26, which are perpendicular to the bottom 24, the front wall 28 is angled, preferably at an angle of about 45 degrees, relative to the bottom 24 so that the compartments 22 flare outward from the bottom.

[0031] The bottom 24 of the compartment 22 defines two generally rectangular openings 30, 32 spaced apart along a longitudinal centerline. The proximal opening 30 is adjacent the angled front wall 28, while the distal opening 32 is disposed at a short edge of the front surface 12 such that it has an open end. The distal ends of the side walls 26 are connected by a pin 34.

[0032] The compartment 22 can receive two pivoting arms 16 that are hinged to the housing 10 via a pin 34 disposed in the compartment 22. At the tail portion 36, each arm has an integrally formed sleeve 38, while a coiled torsion spring 40 is disposed in a slot 42 formed in the arm 16 so as to be coaxial with the sleeve 38. The torsion spring 40 includes two radially projecting tangs 44, 46. The first tang 44 mates with the arm 16 and the second tang 46 mates with the pin 34 in the compartment 22. When the arms are retracted, the first tang 44 moves angularly relative to the second tang 46 to cause a torsional bias of the spring 40. The arms 16 are attached to the pin 34 with an interference fit together with the spring 40. Each arm 16 can pivot about its respective pin 34 so that the arms can be received in the compartment 22 or deployed to form an angle of about 135 degrees therebetween.

[0033] The arm may be biased to open and / or close. For example, two spring plungers may be included inside the arm 16 perpendicular to the side 48. The plungers are slidably displaceable in their associated cylinders so that the plunger tips 55 face outward when the springs are de-energized. The plunger tips 55 may mate in a biased (e.g. spring-biased) manner with corresponding sockets 56 formed in the side walls 26 of the compartment 22 to releasably lock and hold the arm 16 by the spring force against the side walls 26 in the stored state. Thus, in this example, the side walls 26 of the compartment 22 and the arm 16 are biased towards each other via a retaining spring. The spring force and the shape of the sockets 56 define the threshold force required to compress the spring 52 and release the plunger tips 55 from the sockets 56, thereby unlocking the arm 16. The cooperation of the tips 55 and the sockets 56 ensures a secure retention of the arm 16 when stored by the user in a pocket or purse.

[0034] The arm 16 can be accommodated in the compartment 22 by providing the arm 16 with a stepped post shape that complementarily matches the shape of the compartment 22 when the arm 16 is in the retracted position.

[0035] Each arm 16 includes a head portion 60 that is tapered at its distal end to form a concave surface 61 for receiving a chest recording electrode 18. Surface 61 is inclined at an angle of approximately 45 degrees relative to an upper side 63 of head portion 60 so as to be parallel to the front and rear surfaces 12 and 20 of the housing when the arms 16 are in the deployed position, and parallel to the sloped front wall 28 of the compartment when the arms 16 are received in the compartment 22 in the stowed position. Arms 16 are stepped such that an upper side 68 of tail portion 36 is lower than an upper side 63 of head portion 60.

[0036] Head portion 60 of arm 16 has a rectangular base shaped to be received in rectangular opening 30 of compartment 22 when the arm is retracted. At the same time, top side 63 of head portion 60 and bottom side 72 of arm 16 fit flush with front side 12 and back side 20, respectively, of housing 10. In this manner, the most compact size of the device is achieved when not in use.

[0037] Openings 30 in bottom 24 of compartment 22 allow the patient's fingers access to arms 16 from the front, such that sufficient finger pressure is generated to unlock the arms by pressing on upper sides 63 of head portions 60 of arms 16 to move the arms 16 to the deployed position. The upper sides 63 of head portions 60 of each arm are prominently colored to permit operation even in low visibility conditions.

[0038] Four semicircular recesses 73 adapted to receive the tip 55 of a plunger prior to mating with the socket 56 are provided in the rear surface 20 such that each of the recesses is disposed adjacent to and above a corresponding socket 56.

[0039] Two chest recording electrodes 18 disposed on the arms 16 are used to contact the patient's chest in the recording position. When the arms 16 are deployed in the working position, the two chest electrodes 18 may be spaced apart to span a distance of more than about 10 cm in the cranio-caudal direction. The reason for such spacing is that it is advantageous to achieve a distance that is greater than the approximate diameter of the myocardium required to achieve as much lead orthogonality as possible.

[0040] Additionally, when the arms 16 are pivoted and moved to their deployed operating position, the angle between the arms accommodates the curvature of a variety of body shapes, allowing for good contact with the patient's chest regardless of the morphology of the patient's torso.

[0041] According to some variations, in addition to the two chest electrodes, the device further includes two hand recording electrodes 14 disposed on chamfered portions 76 of the front long edge 78 of the device front face 12 for easy finger access. The finger electrodes are used to acquire cardiac signals from the fingers of the left and right hands, preferably by pressing with the patient's thumbs.

[0042] According to an alternative embodiment, the device may include a third electrode disposed on the front surface to be pressed with a finger and used as a ground electrode, the finger pressing creating sufficient pressure on the non-chest electrode attached to the front surface 12 of the housing 10 to hold the device against the chest.

[0043] The recording electrodes 14, 18 are made of a biocompatible plastic material with a contour with spherical protrusions that allow for effective gripping with the patient's chest and fingers to ensure secure holding of the device in place. For operation, a user (e.g., patient) places and presses the device on the chest, e.g., with both hands, including the thumbs, so that each thumb contacts one hand electrode 14, thereby causing the chest electrodes 18 to contact the chest to create a tight contact between the chest and the device. This can create sufficient pressure to hold the device on the chest.

[0044] To prevent misplacement of the device, according to one embodiment, the hand electrodes 14 are offset relative to the lateral centerline of the anterior surface 12 to provide an asymmetric electrode configuration, i.e., during recording, the side of the anterior surface 12 on which the hand electrodes 14 are disposed is oriented toward the patient's head. In this way, the upper and lower sides of the device can be easily distinguished by the patient.

[0045] In the optimal recording position, the center of the device is placed just above the center of the heart, with the chest electrodes approximately on the midclavicular line (a vertical line passing through the midpoint of the clavicle), and the lower chest electrodes approximately at the level of the lower tip of the sternum.

[0046] Additionally, in alternative embodiments, the hand electrodes may be disposed on the front surface of the housing rather than on the chamfered front long edge for ease of access and contact by the fingers. Electrodes for recording ECG signals on the left and right arms by pressing with the fingers other than the thumbs of the left and right hands may be disposed in recessed portions of the front surface rather than on tapered portions of the front long edge as described above for a flush fit with the front surface.

[0047] The active recording electrodes for recording the patient's chest ECG signal are disposed on the pivoting arms of the device in the same manner as described above. At the recording position, the chest electrodes are pressed against the chest in a manner equivalent to that shown above.

[0048] In another alternative embodiment, an additional electrode functioning as a ground electrode may be disposed on the front of the housing to be simultaneously touched by any of the free fingers as pressing the finger recording electrodes causes the device to be pressed against the chest. The ground electrode serves to generate the additional force required to press the device against the chest to perform an accurate recording, and may preferably be made of a biocompatible plastic material with a contoured ball-shaped protrusion to allow effective gripping by the patient's fingers to ensure secure holding of the device in place.

[0049] The optimal position for the handheld device on the chest is with the center of the device on the left side of the chest approximately above the center of the myocardium. In this position, the chest electrode is approximately on the midclavicular line, a vertical line passing through the midpoint of the clavicle, similar to the V4 electrode on a conventional ECG, and the lower chest electrode is approximately at the same level as the lower edge of the sternum.

[0050] The handheld devices described herein are configured to be mechanically stable to allow good electrical contact with the chest while eliminating the possibility of finger contact switching. To prevent wasting recordings by turning the device upside down during a recording procedure, the top or front side of the device may be clearly identified and / or formed (including markings) to be easily distinguished by the patient, for example by integrating LED diodes on the front top surface of the device housing that indicate the current recording stage, such that the top side points towards the patient's toes rather than towards the head. Additionally, since turning the device upside down can lead to recording errors, it is preferable for the top (pointing towards the head) and bottom (pointing towards the toes) of the device to be easily distinguished.

[0051] In some variations, a four recording electrode configuration without a ground electrode (e.g., two chest electrodes and two finger electrodes) is used. This configuration may provide acceptable 50-60 Hz electrical noise performance if a ground-free signal amplifier configuration is used. This recording electrode configuration may also meet the requirement of high orthogonality. The simplest approach to meet this requirement is to record signals in the three main body directions: horizontal (left arm-right arm), sagittal (front-back), and craniocaudal (head-toe). For example, the horizontal signal may be obtained by measuring the leads between the left and right hands. The craniocaudal signal is obtained by measuring the leads between the two chest electrodes, provided that the distance between the chest electrodes is at least 5 cm, and preferably greater than about 10 cm, to be greater than the approximate diameter of the myocardium. In the ideal case, the sagittal signal would be measured between the patient's back and chest, which is not possible due to the constraint of using only finger and chest electrodes. To overcome this, a simple resistive network is used that places the midpoint (CP) close to the electrical center of the heart. To record the leads in a roughly sagittal direction, two hand electrodes and two resistors are used to record the voltage at the lower chest electrode about the midpoint (CP). The two resistors are either equal, each approximately 5 kOhms (kΩ), or unequal, with the first resistor between the left hand electrode and the CP approximately 5 kOhms (kΩ) and the second resistor between the right hand electrode and the CP approximately 10 kOhms (kΩ). This asymmetry reflects the left side location of the heart in the torso, thus shifting the CP to approximately the electrical center of the heart. Thus, a roughly orthogonal three-lead system is obtained. Other lead configurations, with or without a CP, may also be used.

[0052] The handheld device is configured as a stand-alone device incorporating cardiac signal recording circuitry including an amplifier and AD converter for amplifying signals detected by the electrodes, data storage circuitry (e.g., memory) for storing recorded signals, communications circuitry operating on GSM, WWAN, or similar remote communications standards for communicating with a remote processor (e.g., PC computer, pad, smartphone, etc.), and circuitry for communicating diagnostic information to a user in the form of visual and / or audio output (e.g., screen, speaker, etc.).

[0053] The handheld device with a special electrode configuration is capable of recording orthogonal three-lead cardiac signals in an orientation-specific manner and transmitting these signals to a processor (e.g., a PC or other computing device). The remote processor can be configured to diagnose / detect AMI and transmit diagnostic information back to the handheld device.

[0054] Each user can be enrolled in the diagnostic system by performing a first transmission of his / her asymptomatic cardiac recording with three cardiac leads. This first recording can be used as a reference recording for AMI detection in diagnostic recordings (which means further recordings of the same user with three cardiac leads). The availability of a reference cardiac recording can also provide a tool for automatic AMI detection that can distinguish between old and new ST-elevation (STE) or equivalent parameters and other cardiac signal changes suggestive of AMI, with diagnostic accuracy comparable to human ECG interpretation.

[0055] The remote processor may be equipped with diagnostic software for processing the received cardiac signals to generate diagnostic information and for transmitting the information back to the handheld device for communication to the patient. The device may perform automatic detection of cardiac conditions based on the three-lead system, eliminating the need for a professional to interpret the processed diagnostic information.

[0056] The signal processing and diagnostic software may also function on a processor (e.g., a microprocessor) integrated into the housing of the handheld device to process the recorded heart signals and generate diagnostic information. When the diagnostic process is performed by a remote processor, a backup version of the software that functions on the microprocessor is integrated into the handheld device and can be used in situations where the user is in a zone outside the wireless network service area.

[0057] The device can communicate with a remote processor via a communication integrated circuit. The remote processor can communicate with the handheld device via an integrated communication module. The generated diagnostic information can be transmitted from the remote processor (e.g., a PC computer, a server, etc.) to the device memory via a commercial communication network. The handheld device can convey the diagnostic information to the patient in the form of characteristic sounds via a microphone that emits characteristic sounds or voice messages, or in the form of graphic information via a display integrated into the device.

[0058] Example The device described in this specification may be referred to as a signal collection device. FIGS. 6A through 6B illustrate prototypes of exemplary signal (ECG) collection devices shown in a small configuration (FIG. 6A) and a deployed configuration with chest electrodes (FIG. 6B).

[0059] In some variations, the device can be used as part of a subscription service (e.g., a recurring service of x $ / month) signed by the patient or signed by a physician, an insurance company, etc. while the patient signs up for a subscription plan or records an ECG showing symptoms of a cardiac event. The system can provide a report directly to the patient and / or to a physician who can contact the patient. The output (e.g., a report for the patient or the physician) may include advice (go to the ER, call a doctor, etc.). In some variations, the report may include an analysis of the cardiac vector and / or an ECG representation (including a synthetic ECG generated from the cardiac vector / orthogonal leads) along with risk factors. In some variations, a high, low, medium (or other) indication representing the likelihood of a cardiac event can be obtained from the report.

[0060] Alternatively, the reporting is fully automated, with the system generating a score based on a differential comparison between an acutely measured cardiac vector (when the patient suspects a cardiac event is occurring) and a reference cardiac vector (e.g., measured from the patient when no cardiac event is observed on careful review by the system). The system analysis engine generates the score and sends it directly to the patient, either to the handheld signal collection device and / or to a mobile device (e.g., a smartphone) associated with the handheld signal collection device.

[0061] Thus, any of the devices described herein may include software or firmware that is either part of the signal collector and / or part of a mobile device (e.g., a smartphone) in communication with the signal collector. For example, described herein is an application (e.g., an "app") that may drive the processor of the signal collector and / or the mobile communication device and may operate the signal collector to collect patient data (e.g., risk factors), subscribe to a patient, allow the patient to collect one or more ECGs using the signal collector, collect user symptom data associated with the ECGs, and / or provide a user interface for reporting analysis results. The application may provide secure communication between the signal collector and a remote server (e.g., a cloud-based server) for analyzing and storing patient ECG data, risk factors, and other related data.

[0062] For example, in some variations, the patient may use the app to obtain an ECG using the signal collector. The patient launches the app and selects a new recording (baseline or test / symptom ECG), and the app may allow the user to retrieve the recording. The signal collector may in some variations communicate wirelessly (e.g., via a wireless personal area network, including any wireless technology, particularly Bluetooth, etc.) with the mobile communication device running the app. Upon initialization, the app may seek out and automatically activate (and subsequently deactivate) the signal collector, and either the signal collector or the app (or a combination of both) may detect skin contact and begin recording from the chest and finger electrodes. The recorded signals (from all three leads, including the virtual sagittal lead derived from the center point of the resistive network between the left and right hand electrodes as well as one of the chest electrodes, e.g., the lower chest electrode) may be processed by the signal collector and / or the application (e.g., a smartphone), including processing to accommodate sufficiently low noise and quality of the collected data. The recorded signals may be stored in the signal collector and / or the mobile communication device during use, and may be transmitted to a remote server at a later time. The signal collection device may include a storage device and / or the signals may be stored on the patient's smartphone and then transmitted to a remote server (e.g., the cloud) for analysis and processing.

[0063] Generally, the analysis may include a baseline analysis. A baseline ECG (e.g., a baseline cardiac vector) may be acquired when the patient first subscribes and / or purchases the device. The baseline signal may be thoroughly examined by the system. For example, the baseline signal may be examined to ensure that it is within some predefined "normal" parameter range. For example, the patient's baseline signal may be determined by performing a difference vector analysis of the baseline cardiac vector determined from three orthogonal leads of the signal acquisition device. Multiple baseline measurements may be taken and averaged or the best one selected. If the baseline does not fall within expected parameters, for example because it has an irregular cardiac vector for any reason (including a concurrent undetected cardiac event), the patient may be rejected as an unqualified candidate. The system may periodically prompt the user to provide an updated baseline signal.

[0064] In some variations, the application software may perform quality control (QC) checking signals (e.g., QC agents, software agents, etc.) that may indicate whether the reference cardiac vectors are sufficient. This may be done in real time and may include both signal quality checks that may be performed on either or both the signal collection device and the mobile communication device (e.g., a smartphone) and / or on a remote server. The QC agent may seek signal clarity and / or may also verify that the patient is not having a heart attack. This may be part of the final level quality check.

[0065] The application software / firmware may also obtain risk factors from the patient. Advantageously, this may occur at the time of subscription. The patient may be presented with a series of questionnaires and / or have access to electronic medical records representative of risk factors associated with cardiac disease (e.g., heart attack, etc.). Information may include patient specific information (age, sex, weight, height, ethnicity, cholesterol levels, blood pressure, etc.). The questionnaires may be sequenced and weighted. Entry of minimum risk factor information (e.g., age only, age and sex only, etc.) may be permitted. If the minimum information is not entered, the patient will not be permitted to subscribe.

[0066] As mentioned above, the application may prompt the patient to update their baseline periodically (e.g., weekly, bimonthly, monthly, etc.) by sending messages (SMS / text messages) within the app or without the app (from a remote server).

[0067] In use, a patient may use the app to initiate an ECG recording for testing (e.g., when experiencing symptoms associated with a cardiac event or feeling at risk for a cardiac event) or to update, for example, symptomatic or asymptomatic criteria. The user may initially indicate what type of recording is to be made. If the patient indicates symptoms are present, the app may expedite the ECG recording and analysis to provide a real-time response as quickly as possible. After the user initiates the app and indicates through the user interface that they would like a symptomatic ECG analysis to be performed, the system may make a recording of three orthogonal leads that provide a cardiac vector (and may obtain two or more recordings using a QC agent). This recording may first be reviewed locally or remotely (e.g., at the signal collection device, smartphone / app, and / or at a remote server) to determine whether the recent cardiac vector indicates that a cardiac event is likely to occur. Based on the differential vector analysis of the cardiac vector (compared to the reference cardiac vector), and in some variations in conjunction with the recorded patient-specific risk factors, if the likelihood exceeds a cut-off threshold, the patient is immediately instructed, for example, through the app or by contacting directly (e.g., by phone) to seek treatment. In some variations, a medical professional may be directly contacted. If the preliminary analysis score is below the threshold, the patient may be prompted to provide additional symptom information, such as location, duration, and / or pain intensity, pain type, pain acuity, etc. The symptom information is collected by the app and transmitted to a remote server, which combines this information with the patient risk factors and differential cardiac vector information to create a final score that is sent to the patient and / or medical professional. If the score is above the threshold, indicating a possible cardiac event, the patient may be instructed to seek immediate treatment and / or may be automatically contacted to perform a medical intervention. If the score is in the intermediate range, the patient may be instructed to follow up with a medical provider. If the score is in the low probability range, the patient may also be notified of this. For intermediate or low scores, the patient may be instructed to perform a follow-up interpretation over a predetermined amount of time (e.g., 10 minutes, 20 minutes, 30 minutes, etc.), which may be adjusted by the app.

[0068] Alternatively, in some variations, the report is sent to a physician who may manually or semi-manually interpret the results, including risk factors and symptoms, and contact the patient directly, including via an app.

[0069] FIG. 7 illustrates an example of a patient 700 holding a signal collector 703 on his chest. The signal collector includes a pair of extendable / pivotable chest electrodes 709, 711 that when extended contact the chest (positioned vertically as shown) spaced 10 cm or more apart; two finger electrodes, one 707 on the left and one 705 on the right, are used to complete electrical contact to hold the small, lightweight device on the chest as shown. These contacts allow three leads to be determined with high orthogonality (between the finger electrodes, between the chest electrodes, and between the center point of the resistive network between the finger electrodes and one of the chest electrodes). The device may wirelessly communicate with a mobile communication device (e.g., a smartphone) that may include an app (software or firmware) to check signal quality and / or perform additional recordings. The app may provide visual, auditory, tactile, or some combination of these indications that a recording has been made. The recordings may be transmitted to a remote server, as shown diagrammatically in FIG. 8.

[0070] 8 illustrates generally an example of a system including a signal acquisition device 800 that can be used to determine three orthogonal leads 804 that precisely define a cardiac vector, which can then be transmitted to the patient's mobile telecommunications device 806 (e.g., phone, i-pad, wearable electronics, etc.) that can process and / or check the quality of the signal and store and / or transmit the signal to a remote server 810. The remote server can communicate with the patient (e.g., and with the patient's mobile telecommunications device) or with a monitoring service and / or a physician (not shown).

[0071] The methods and devices described herein may be used in conjunction with (and may be improvements upon) U.S. Patent Application No. 15 / 096,159, entitled "MOBILE THREE LEAD CARDIAC MONITORING DEVICE AND METHOD FOR AUTOMATED DIAGNOSTICS," filed April 11, 2016, which claims priority to U.S. Provisional Patent Application No. 62 / 145,431, entitled "MOBILE THREE LEAD CARDIAC MONITORING DEVICE AND METHOD FOR AUTOMATED DIAGNOSTICS," filed April 9, 2015, both of which are incorporated herein by reference in their entireties.

[0072] For example, a 3-lead mobile cardiac monitoring device having the first small non-deployment configuration and the second deployment configuration described in this specification is used for automatic remote diagnosis of cardiac conditions and may include an automatic diagnosis method using these improved handheld cardiac devices. These methods and devices may implement a risk scoring model based on three risk elements, namely, the existing risks associated with the patient's risk factors, the chest pain risk associated with the current symptom risk, and the recorded cardiac signals. These methods and devices use risk factors and current symptoms as additional inputs in addition to three orthogonal cardiac signal leads, so that not only AMI but also other cardiac symptoms such as angina can be detected. In addition, accurate settings for cardiac diagnosis can be provided using manually entered patient-related data, especially in cases where cardiac signal recording has low accuracy and precision due to measurement interference. Therefore, by enabling not only automatic diagnosis of serious cardiac conditions but also high-accuracy diagnosis, the methods and devices described in this specification can improve the operation of current solutions. The methods and devices may be configured to include data acquisition, data processing (e.g., application of a scoring model), and transmission of diagnostic information about the cardiac condition to the patient. In a situation where the symptoms are related to an ongoing AMI or a similar situation, the method may be implemented in a device configured as a handheld device that enables input of patient-related data (e.g., existing risk and current symptom risk data), recording of cardiac signals by the patient, and retrieval of previously stored cardiac risk-related data. Any of these systems may include a 3-lead mobile cardiac monitoring device having the first small non-deployment configuration and the second deployment configuration described in this specification. These systems may also include a memory for storing the patient's cardiac risk factor data, together with a user interface for inputting the patient's cardiac risk factor data and current symptom data in text form. Once acquired, the data may be transmitted to a remote processor. The processor may be configured to provide diagnostic information to the patient and also transmit the diagnostic information to the handheld device. The patient may decide to take further action, such as requesting emergency medical treatment, based on the received information. The handheld device may communicate the diagnostic information to the patient via a characteristic sound, voice message, or graphical display.The processor may be configured via hardware, software, firmware, etc. to process the received signals and generate a differential signal to reliably extract information relevant to detecting AMI.

[0073] For example, a three-lead mobile cardiac monitoring device having a first compact undeployed configuration and a second deployed configuration as described herein may be configured to be operated by a patient when a cardiac symptom occurs. The device may include storage (e.g., memory) for storing data about the patient's cardiac risk factors and other data, and cardiac signal recording components (e.g., electrodes, circuitry, controller) for recording the patient's cardiac signals. The recording components may be similar to those disclosed in WO 2016 / 164888 by Bojovic et al., as discussed above. By equipping the device with a graphical user interface (e.g., a touch screen or a screen and keyboard, etc.), patient-related data (risk factors and current symptoms) may be entered and diagnostic messages may be communicated to the patient. Diagnostic information may also or alternatively be communicated to the patient through a characteristic sound or voice message via a speaker. Communication may occur via a wired or wireless connection to an independent user-operated device, such as a smartphone or tablet.

[0074] As described above, a three-lead mobile cardiac monitoring device having a first compact undeployed configuration and a second deployed configuration may be configured to record three substantially orthogonal cardiac signal leads using two chest electrodes and two non-chest (finger) electrodes. In some electrode configurations, the device may have a ground electrode integrated somewhere on the surface of the device.

[0075] The three-lead mobile cardiac monitoring device having the first compact undeployed configuration and the second deployed configuration described herein may have various electrode configurations for recording three orthogonal cardiac lead signals. In one embodiment, the handheld device has two chest recording electrodes, one finger recording electrode on the left side of the device, one (or in some variations two) finger electrodes on the front side of the device, and one recording and one ground electrode. The optimal position of the handheld device on the chest is such that the center of the device is on the left side of the chest approximately above the center of the myocardium. In this position, the chest electrodes are approximately on the midclavicular line, a vertical line passing through the midpoint of the clavicle, and the lower chest electrode is approximately at the level of the lower end of the sternum, similar to the V4 electrode of a conventional ECG.

[0076] A four recording electrode configuration (e.g. with two chest electrodes and two finger electrodes) can meet the requirement of high orthogonality, for example, by recording signals in the three main body directions: horizontal (left arm-right arm), sagittal (front-back) and craniocaudal (head-toe). For example, horizontal signals can be obtained by measuring the lead between the left arm and the right arm. Cranial-caudal signals can be obtained by measuring the lead between the two chest electrodes with the distance between the chest electrodes in the craniocaudal direction being at least 5 cm, preferably greater than about 10 cm, so as to be larger than the estimated diameter of the myocardium. In the ideal case, sagittal signals are measured between the patient's back and chest, which is not possible under the constraint of using only one finger electrode and chest electrode. To overcome this, a central point (CP) close to the cardiac electrical center is provided in the simple resistive network. To record the approximately sagittal leads, the voltage of the lower chest electrode is recorded with respect to the central point (CP) obtained using two hand electrodes and two resistors. The two resistors may be equal, each approximately 5 kOHM, or may be unequal, with the first resistor between the left hand electrode and the CP approximately 5 kOHM and the second resistor between the right hand electrode and the CP approximately 10 kOHM. This asymmetry reflects the left-side location of the heart in the torso, thus shifting the CP approximately to the electrical center of the heart. In this manner, a nearly orthogonal three-lead system is obtained.

[0077] Other similar lead configurations including the same CP can be selected using the same set of two chest electrodes and two hand electrodes. For example, such lead configurations can be nearly orthogonal when both chest electrodes are used to record leads with a CP reference electrode. Another possibility to define the CP is to use three electrodes, two hand electrodes and one chest electrode, and three resistors connected in a Y (star) configuration.

[0078] Other lead configurations that do not include a CP may also be used, such as a configuration that records two chest electrodes and a right hand electrode signal relative to a left hand electrode signal. Such configurations without resistors or CPs have a higher noise immunity, e.g., to 50-60 Hz electrical noise, but have less orthogonality in the orthogonal lead directions than the described configurations that use CPs. Generally, any other lead configuration that uses the same four electrodes as described (20 total configurations without CPs) will result in leads that are non-coplanar and therefore capture diagnostic signals in all three directions, but may lack a high degree of orthogonality. However, these configurations may have different levels of orthogonality depending on the use of the right hand electrode. The configuration that uses the right hand electrode as a common reference electrode for all three leads may have the lowest orthogonality, since the right hand electrode is the furthest from the heart of the four electrodes and therefore has the smallest angle between the vectors corresponding to the three leads. However, this configuration with the lowest orthogonality is best suited for reconstructing a 12-lead ECG based on the three lead signals, since it has a smaller non-dipole content. Nonetheless, the signals obtained using this configuration may be used with or without the inclusion of a 12-lead reconstruction.

[0079] The validity of the described solution is not affected if one or more chest electrodes are added to the back of the device, and one or more corresponding additional leads are recorded and used in the diagnostic algorithm, nor is the validity affected if the front electrode is pressed against the palm or other parts of the hand rather than the fingers.

[0080] For example, the devices described herein may be used for remote diagnosis of cardiac conditions such as acute myocardial infarction (AMI), atrial fibrillation (AFib), and others. In particular, described herein is a handheld device with a specialized electrode configuration that allows recording three orthogonal cardiac lead signals in an orientation-specific manner and transmitting these signals to a processor (e.g., a PC or other computing device). The processor may be configured to diagnose / detect AMI and transmit diagnostic information to the handheld device as well. The handheld device may communicate the diagnostic information to the patient via a distinctive sound, audio message, or via a graphical display. The processor may be configured via hardware, software, firmware, or otherwise to process the received signals to generate a difference signal and extract information that is reliably related to the detection of AMI (and additional information of clinical relevance). Thus, these devices and methods perform automatic detection of cardiac conditions based on a three-lead system without the need for 12L ECG reconstruction, reducing or eliminating the need for medical personnel to interpret the ECG, unlike prior art systems that typically rely on medical personnel for such determinations. The automated diagnostic methods described herein, in combination with improved handheld cardiac devices, address many of the needs and problems present in other systems.

[0081] For clarity, described herein is a three-lead cardiac recording device for user placement on the chest that includes placement of electrodes on both the front and back (or alternatively on one or more sides, e.g., the anterior oblique side), so that the device can be held by both hands of the user in a default orientation to record three-lead cardiac signals when held on the user's chest. To perform the functions described above, the handheld device may record the three leads without the use of cables (e.g., may include only surface electrodes that are held or held on the body). Furthermore, the resulting three leads are non-coplanar and as close to orthogonal as possible. Finally, at least one electrode may be attached to the front (and / or oblique side) of the device opposite the chest side to generate the force necessary to hold the device on the chest. The apparatus and methods described herein do not require reconstruction of a 12L ECG from the three measured leads, so the requirement of low non-dipole content does not arise.

[0082] The three-lead mobile cardiac monitoring device with the device in the first miniature undeployed and second deployed configurations described herein is configured to be mechanically stable and allow good electrical contact with the chest while avoiding the possibility of finger contact switching. The handheld device may be placed on the chest with the center of the device on the left side of the chest approximately above the center of the myocardium. In this position, the chest electrode is approximately on the midclavicular line, a vertical line passing through the midpoint of the clavicle, and the lower chest electrode is approximately at the level of the lower edge of the sternum, similar to the V4 electrode of a conventional ECG. The horizontal signal may be obtained by measuring the lead between the left and right hand. The craniocaudal signal may be obtained by measuring the lead between the two chest electrodes, with the distance between the chest electrodes in the craniocaudal direction being at least 5 cm, preferably greater than about 10 cm, so as to be greater than the estimated diameter of the myocardium. In the ideal case, the sagittal signal is measured between the patient's back and chest, which is not possible under the constraint of using only finger and chest electrodes. To overcome this, a simple resistor network is used to provide a midpoint (CP) close to the electrical center of the heart. To record the lead in an approximately sagittal orientation, the voltage of the lower chest electrode is recorded about the midpoint (CP) which is obtained using two hand electrodes and two resistors. The two resistors are either equal and approximately 5 kΩ each, or unequal, with the first resistor between the left hand electrode and the CP being approximately 5 kΩ and the second resistor between the right hand electrode and the CP being approximately 10 kΩ. This asymmetry reflects the left-side position of the heart on the torso, thus shifting the CP to approximately the electrical center of the heart. Thus, a nearly orthogonal three-lead system is obtained.

[0083] The 3-lead mobile cardiac monitoring device having the first small non-deployment configuration and the second deployment configuration described in this specification can be configured as a stand-alone device incorporating an ECG recording module including an amplifier and an AD converter, a data storage module, a communication module operating with a similar remote communication standard for communication with GSM, WWAN, or a remote processor (such as a PC computer, a pad, a smartphone, etc.), and a circuit configuration (such as Wi-Fi, Bluetooth, etc.) for transmitting diagnostic information to the user. Alternatively, this can be implemented in conjunction with a mobile phone.

[0084] The signal processing and diagnostic software can function not with a remote processor (such as a PC computer) but with a processor (such as a microprocessor) integrated into a handheld device. In this case, except for data and processing backups, communication of the recorded information to a remote computer is no longer necessary. Also, when diagnostic processing is performed by a remote processor, a backup version of the software that functions with the microprocessor is integrated into the handheld device and can be used in situations where the user is in a zone outside the wireless network service area.

[0085] Also described herein are methods and devices for the automatic detection of AMI (or ischemia, the underlying physiological process) using the 3-lead mobile cardiac monitoring device having the first small non-deployment configuration and the second deployment configuration described in this specification. These automatic systems include three cardiac leads that are substantially orthogonal and store most of the diagnostic information present in a conventional 12-lead ECG. Each user can be registered with the diagnostic system by performing an initial transmission of their asymptomatic cardiac recording with the three cardiac leads. This initial recording can be used as a reference recording for AMI detection of the diagnostic record (the diagnostic record means further recordings of the three cardiac leads of the same user). Due to the usefulness of the reference cardiac recording, it is possible to distinguish between new and old ST segment elevation type (STE) or equivalent parameters, and other cardiac signal changes also suggest AMI, resulting in an automatic AMI detection tool that can have a diagnostic accuracy comparable to that of human ECG interpretation.

[0086] In one example, a user may place the device in a different position compared to the reference position, which may impair diagnostic accuracy. This misplacement is equivalent to a virtual shift of the cardiac electrical axis in the 3D vector space defined by the three cardiac leads. In some variations, this angular shift may be calculated for each test recording and compared to the reference recording. If the angular shift is greater than a threshold, such as 15 degrees, the user may be warned to select a position closer to the reference position. If the shift is less than the threshold, this may be corrected by rotating the signal loop of the test recording in the 3D vector space to obtain a signal approximately equivalent to the reference signal.

[0087] A method for automatic detection of AMI (or ischemia) may, in some variations, include the steps of: placing the device at a recording location on the user's chest; acquiring an initial three-lead cardiac recording using a three-lead mobile cardiac monitoring device having a first compact undeployed configuration and a second deployed configuration as described herein and communicating the signals to a processing unit; storing the first recording as a reference recording in a database of the processing unit for further comparison with any subsequent diagnostic recordings; acquiring a three-lead cardiac diagnostic recording and communicating the signals to the processing unit; processing the resulting signals. Processing by the processing unit of the stored reference signals and the signals of the diagnostic recording may include the steps of: pre-processing to remove power line interference, baseline drift, and muscle noise; obtaining a typical heart rate using a fiducial point and average heart rate procedure; checking for left and right finger switching; performing heart rate alignment to bring the typical heart rates of the reference and test recordings into the same time frame so that corresponding points are synchronized; correcting chest electrode misplacement in the recording of the test signal by correcting for cardiac electrical axis deviation in the vector space of the three cardiac leads. calculating a differential signal representative of changes between the baseline and diagnostic three cardiac lead signals, detecting cardiac signal changes indicative of ischemia by comparing parameters of the test recordings with the baseline recordings or by comparing parameters of the differential signal with predefined thresholds, communicating the information by the processing unit to the device, and finally conveying the diagnostic information to the patient by the device.

[0088] STE is the most common ECG change in cases of ischemia, usually measured at the J point or up to 80 milliseconds later. Using STE as a parameter, ischemic changes can be detected by comparing the STE of a test recording with a reference recording. Also, ischemic changes can be detected by measuring the vector difference (STVD) of the ST vector in the vector space defined by three special cardiac leads, with the reference recording as a reference value. As mentioned above, these parameters (e.g., ST, J, STVD, STE) are defined for a traditional 12-lead ECG signal, but refer to equivalent measures as determined for the three cardiac leads (orthogonal signals) described herein. Thus, these equivalent points, regions, or phenomena (e.g., STE, ST, J, STVD, etc.) can be identified by comparing the cardiac signals described herein with traditional ECG signals, including traditional 12-lead ECG signals.

[0089] Other parameters of the cardiac signal may also be used for comparison with a baseline reference signal, such as the "clue," defined as the radius of a sphere enclosing the vector signal hodograph between points J and J+80 ms.

[0090] The cardiac signal for an individual is highly repeatable as far as its shape is concerned. Changes in signal shape are generally small for healthy or stable individuals. For example, changes in the position of the heart relative to the rib cage can change the cardiac electrical axis by up to 10°. However, conditions are found in which the signal shape changes over time, such as STE caused by bilateral early repolarization (BER). Such signal changes can be highly individual and significant. To correct for such changes, several reference recordings acquired by the user over time can be used to form a reference value that forms a 3D contour in a vector space defined by three specific cardiac leads (rather than a single point when a single reference recording is used). When using such a 3D contour reference value, the ST vector difference (STVD) can be defined as the distance from the 3D contour, rather than from a reference ST vector. When more than one parameter is used for ischemia detection, such a reference contour can be constructed as a hypersurface in a multidimensional parameter space defined by such parameters. In this case, the hyperdistance from the reference hypersurface is defined in this parameter space.

[0091] In some conditions, signal shape changes may be intermittent (conditions "come and go"), such as Brugada syndrome, WPW syndrome, cord branch block (BBB), etc. To correct for signal changes in such conditions, two groups of reference recordings (e.g. at least two recordings), one with normal signal and one where intermittent conditions exist, may be used to define a reference value. These two groups form two 3D contours in a vector space to form a reference value for comparison. These two 3D contours may or may not overlap. In case of no overlap, the ST vector difference (STVD) will be defined as the distance from the closest points on the two 3D contours. In case more than one parameter is used for AMI / ischemia detection, such reference contours may be constructed as two hypersurfaces in a multidimensional parameter space defined by such parameters. In this case, the hyperdistance from the reference hypersurface is defined in this parameter space.

[0092] The primary use of the methods described herein may be applied to the most urgent cardiac diagnosis - detection of AMI. Additionally, diagnostic methods (e.g., software) on a remote processor (or integrated processor in a handheld device) can detect other cardiac conditions such as chronic coronary artery disease (CAD), left ventricular hypertrophy (LVH), heart rhythm disorders such as cord branch block (BBB), Brugada syndrome, atrial fibrillation (AF), etc.

[0093] The methods described herein do not require reconstruction of a conventional 12-lead ECG recording, although they may be used for reconstruction. Many of the above conditions detected may require urgent treatment, although to a lesser extent than AMI. Also, many of these conditions are transient and may be detected using the techniques described herein, but may not be present at a later visit to the clinic by the user. In such cases, it is useful to present an ECG signal for the condition found at the time of recording, which the physician may use to confirm the diagnosis. Physicians are familiar with conventional 12-lead ECG recordings. Therefore, the three special cardiac leads recorded when the condition is found may be transformed to generate an approximate reconstruction of the conventional 12-lead ECG recording. Such a reconstruction is obtained by multiplying the three special cardiac leads with a 12×3 matrix. This matrix is ​​a population matrix, i.e. a matrix with coefficients calculated as the mean or median of individual matrices obtained by simultaneously recording a conventional 12-lead ECG and the three special cardiac leads in a population of individuals, each individual matrix being obtained using a least squares method. The coefficients of such a matrix depend on the user's body shape. Therefore, rather than using a single population matrix, multiple matrices may be used that may be easy to obtain by users for a user population, each defined by simple parameters of body shape and structure such as gender, height, weight, chest circumference, etc. Also, the matrix coefficients may be determined as continuous functions of such body parameters.

[0094] FIG. 9A illustrates one variation of a method of operating a system for cardiac signal detection and / or diagnosis. In FIG. 9A, a user 2 records a cardiac signal (e.g., two or more times) and a device 3 (specifically a three-lead mobile cardiac monitoring device having a first compact undeployed configuration and a second deployed configuration as described herein) processes the three orthogonal leads to compare time differences (e.g., baseline and test times). The processor of the device 3 can then determine whether the resulting differential signal is indicative of a cardiac problem and alert the user. The user (patient) can then obtain medical assistance if necessary. FIG. 9B illustrates another variation of a system and method for detecting cardiac dysfunction, including a system 1 for remote diagnosis of AMI, including a handheld device 2 incorporating built-in electrodes for cardiac signal acquisition that are attached directly to the housing 3 of the handheld device, and a PC computer 4 connected to the device via a remote communication link.

[0095] The three-lead mobile cardiac monitoring device having the first compact non-deployed configuration and the second deployed configuration described herein may further incorporate cardiac signal recording circuitry including an amplifier and an AD converter for amplifying signals detected by the electrodes, data storage (e.g., memory) for storing the recorded signals, and communications circuitry operating on GSM, WWAN, or similar remote communications standards for communication between a remote processor 4 and visual and / or audio (e.g., monitor, speaker, etc.) for communicating diagnostic information to a user.

[0096] The three-lead mobile cardiac monitoring device having the first compact non-deployed configuration and the second deployed configuration described herein may communicate with a remote processor 4 via integrated communication circuitry. The remote processor 4 may communicate with the handheld device 2 via an integrated communication module. The processor 4 may be equipped with diagnostic software for processing the received cardiac signals to generate diagnostic information and for transmitting information to the handheld device as well to convey the diagnostic information to the patient via a microphone generating characteristic sounds or voice messages or in the form of graphic information via a display integrated in the device. As a result, the system is capable of performing automatic detection of cardiac conditions based on the three-lead system and does not require interpretation of the processed diagnostic information by an expert. Alternatively, instead of a remote processor, the system may include a microprocessor integrated in the housing 3 of the handheld device for processing the recorded cardiac signals to generate diagnostic information.

[0097] The example of FIG. 10 shows a simple electrical method for obtaining the central point CP by connecting the electrodes on both hands through a simple resistive network with two resistors.

[0098] FIG. 11A shows a spatial diagram of a lead configuration according to one embodiment illustrating the relative placement between the electrodes along with the placement of the active electrodes A, B, C, D relative to the body. FIG. 11B shows a simplified electrical scheme illustrating the same relative placement between the electrodes shown in FIG. 11A. To record a generally sagittal lead, the voltage of the lower chest electrode B can be obtained about a center point CP using the hand electrodes C, D and two resistors R1, R2. The two resistors R1, R2 can be equal and each approximately 5 kΩ, or unequal and approximately 5 kΩ between the left hand electrode and the CP and 10 kΩ between the right hand electrode and the CP. This asymmetry reflects the left-side location of the heart in the torso, thus placing the CP point approximately at the electrical center of the heart. In this way, a generally orthogonal three-lead configuration is obtained.

[0099] Figure 11C shows a spatial diagram of an alternative lead configuration including a central point CP using the same set of chest and hand electrodes A, B, C, D illustrating the relative placement between the electrodes along with the placement of the electrodes on the body. Figure 11D shows a simplified electrical scheme illustrating the same relative placement between the electrodes A, B, C, D shown in Figure 11C. This alternative lead configuration using the central point CP to measure two leads between the CP and each of the chest electrodes is also nearly orthogonal since chest electrodes A, B are used to record the leads with the CP obtained using two hand electrodes C, D and two resistors R1, R2 as the reference electrode.

[0100] Other lead configurations without a central point CP and resistors can also be used, such as the configuration shown in FIG. 11E, which records signals from two chest electrodes and a right-hand electrode for a left-hand electrode. Two other similar configurations are shown in FIGS. 11F and 11G. Such configurations without resistors receive less external interference, such as 50-60 Hz electrical noise, but have less orthogonal lead directions than those described above that use CPs. Generally, other lead configurations using the same four electrodes as those described result in non-coplanarity and therefore lack high orthogonality, although they capture diagnostic signals in all three directions. A total of 20 configurations are possible that do not include CPs, including those shown in FIGS. 11E, 11F, and 11G. However, these configurations have different levels of orthogonality depending on the use of a right-hand electrode. The configuration using the right-hand electrode as a common reference electrode for all three leads has the lowest orthogonality, since the right-hand electrode is the furthest from the heart of the four electrodes and therefore has the smallest angle between the vectors corresponding to the three leads. Configurations using right-hand electrodes on two leads, such as the configuration shown in FIG. 11F, have good orthogonality, but the best orthogonality is achieved in configurations using right-hand electrodes on only one lead, such as the configurations shown in FIGS. 11E and 11G.

[0101] 12 shows a block diagram of a method for automatic detection of AMI according to a preferred embodiment of a 3-lead mobile cardiac monitoring device having a first compact undeployed configuration and a second deployed configuration as described herein. The method for automatic detection of AMI (or ischemia) may include all or some of the steps described below. First, place the device in a recording position on the user's chest.

[0102] The optimal position for the handheld device on the chest is with the center of the device approximately above the center of the myocardium and on the left side of the chest. In this position, the chest electrodes are approximately on the midclavicular line, a vertical line passing through the midpoint of the clavicle, and the lower chest electrode is approximately at the level of the lower edge of the sternum, similar to the V4 electrode of a conventional ECG. On the front of the device, the user presses down on one active electrode and one ground electrode with the fingers of the left hand and one active electrode with the fingers of the right hand.

[0103] The method may also include obtaining an initial three-lead cardiac recording and communicating the signals to a processing unit. A user of the automated AMI diagnosis system may perform a recording of the three-lead cardiac signals by holding a handheld device against the chest for a short period of time (e.g., at least 30 seconds, at least 20 seconds, at least 10 seconds, at least 5 seconds, etc.). The recording is stored in the device's memory and then transmitted over a commercial communications network to a remote PC computer.

[0104] The method also includes storing the first recording in the database of the processing unit as a reference. After performing the first transmission of his / her cardiac signal, the cardiac signal record is stored in the remote processor and the user can be registered in the diagnostic system. Before this first transmission, the user or his / her MD / nurse inputs (via a dedicated website) medical data such as age, sex, risk factors for cardiovascular disease, etc., and indicates whether he / she currently has chest pain or other symptoms suggestive of ischemia. If the answer is negative, this initial cardiac recording is retained in the diagnostic system as a reference record that serves as a reference value for comparison in further transmissions when symptoms suggestive of ischemia occur.

[0105] This method may further include acquiring a three-lead cardiac diagnostic recording and communicating the signal to a processing unit. Subsequent recordings after a reference recording has been accepted and stored in a database are considered diagnostic recordings. A user of the automated AMI diagnostic system performs a diagnostic recording of the three-lead cardiac signal by holding a handheld device against the chest for at least 10 seconds. The diagnostic recording is stored in the memory of the device and then transmitted via a commercial communication network to a remote PC computer.

[0106] Generally, the methods described herein may include processing the signals of the stored reference and diagnostic recordings by a processing unit. The processing may include preprocessing. For example, the device / method may be configured such that Va, Vb, Vc are three special leads recorded using a handheld device. Prior to performing any analysis, disturbing factors such as power line interference, reference fluctuations, and muscle noise must be "removed" from the cardiac signal. The former two are removed using standard adaptive filtering and cubic spline techniques respectively, while the latter is suppressed using a time-averaged central heart rate procedure.

[0107] To determine the central heart rate, the entire cardiac signal is enumerated, and as a result, a set of reference points S = {P 1 , P 2 ,..., P n} is obtained, where P i = {Q i , R i , J i , T i , end} (or points equivalent to these locations) are the reference points of the i-th heart rate. Then, based on S, the signal is divided into n individual heart rates of the same length. Finally, the individual heart rates are synchronized using cross-correlation (CC), and for each sample, the median of all n heart rates is calculated. Thus, the entire cardiac signal is represented by a single most typical central heart rate. The set of reference points P = {Q, R, J, T, T end} related to the central heart rate is easily calculated as the median of the reference points of the individual heart rates.

[0108] Techniques for obtaining a typical heart rate rather than a median heart rate may also be used. A variety of techniques such as wavelet transforms, support vector machines, etc. may be used to enumerate the cardiac signal at the fiducial points of each heart beat.

[0109] The same preprocessing procedures are used for both baseline and diagnostic recordings.

[0110] If a lead recorded between the left and right hands, or any other lead that captures a signal horizontally, is reversed, the user is alerted to repeat the recording using the correct recording position.

[0111] The process may also include heartbeat alignment. For example, the device or method may be configured to let B and D refer to median heart rates extracted from the reference and diagnostic cardiac signals, respectively, with PB and PD being their associated reference points. The goal of heartbeat alignment is to bring B and D into the same time frame so that corresponding points are precisely synchronized. This requires finding a transformed B, called B*, that is optimally synchronized with D. The transformation applied is a piecewise uniform resampling of B, so that corresponding segments of B* and D, defined by PB and PD, respectively, have the same number of samples. The optimal alignment is obtained by searching for a reference point PB* that optimizes a cost function or similarity measure (SM) that quantifies the alignment.

number

[0112] In this embodiment, we used CC, which is a commonly used SM for shape-based alignment problems. However, because the shapes of B and D are very different, using only CC may lead to alignment errors. Therefore, the reference point P B is assumed to be known accurately, so P B A weighting function f that penalizes large deviations from wi Introduce the following.

number

number

[0113] Finally, according to equation (1), B* is found by finding the optimal value of SM given by equation (3).

[0114] The processing may also include correction for misplacement of the chest electrodes. During normal use of the handheld device, the chest electrodes are not placed in the same place every time, which may lead to changes in the shape of the cardiac signal even in the absence of any pathology. Assuming that the lead positions are constant, this change is modeled as a "virtual" cardiac electrical axis deviation in the Va, Vb, Vc lead vector space, where the cardiac electrical axis is represented by the R vector - the cardiac vector at the maximum magnitude moment at the QRS complex (or the equivalent region of the 3-lead cardiac signal as described herein). However, this is an undesirable characteristic, since it results in a large difference signal ΔD even in the absence of pathology-induced changes. To overcome this problem, D is transformed so that D*=TD, so that its cardiac electrical axis overlaps with that of B*. A transformation T is calculated using a least squares method and the Q-J segments (QRS complexes) of D and B* as inputs.

[0115] In general, the processing may also include calculating a difference signal representative of the change between the reference and diagnostic cardiac lead signals. The difference signal ΔD* is calculated as follows:

number

[0116] Finally, such a difference signal ΔD* reflects only pathology-induced changes and is independent of cardiac axis deviation.

[0117] Since the quality of the device misplacement correction decreases with increasing signal axis angle deviation, the user is prompted to select a position closer to the reference position when the angle change is greater than a threshold value, such as 15 degrees.

[0118] The processing methods and devices described herein may also include detection of changes due to ischemia. STE is the most common ECG change in case of ischemia, usually measured at the J point or up to 80 ms later. In this solution, ischemic changes are detected by comparing the test recording with a reference recording. In a preferred embodiment, the parameter or "marker" for ischemia detection is the vector magnitude of the corrected difference signal ΔD* 80 ms after the J point (J+80 ms) compared to the STVM (or equivalent area of ​​the cardiac signal as described herein), i.e., a predefined threshold such as 0.1 mV.

[0119] In other embodiments, vector magnitudes at other time points may be used as markers of ischemia, such as the J point, J+60 ms, Tmax, etc. Other markers representing the shape of the ST segment (the segment of the ECG signal between the J and J+80 ms points, or similar) may be used. Such a marker is the "clew", which is defined as the radius of a sphere that encloses the vector signal hodograph between the J and J+80 ms points. Other composite markers may also be used, such as logistic regression using a linear combination of STVM and clew markers.

[0120] To correct for signal shape changes over time, several reference recordings acquired by the user over a period of time (instead of a single point when a single reference recording is used) can be used to form a reference that forms a 3D contour in a vector space defined by three specific cardiac leads. When using such a 3D contour reference, the ST vector difference (STVD) is defined as the distance from the 3D contour, not from the reference ST vector. When more than one parameter is used for ischemia detection, such a reference contour will be constructed as a hypersurface in a multidimensional parameter space defined by such parameters. In this case, the hyperdistance from the reference hypersurface is defined in this parameter space.

[0121] For users with cardiac conditions involving intermittent cardiac shape changes, correction for such changes may be performed by forming two groups of reference recordings (at least two recordings), one with normal signals and one with this condition, to define a reference value. These two groups will form two 3D contours in vector space to form a reference value for comparison, and the ST vector difference (STVD) will be defined as the distance from the closest points on the two 3D contours. When more than two parameters are used for ischemia detection, such reference contours will be constructed as two hypersurfaces in a multidimensional parameter space defined by such parameters. In this case, the hyperdistance from the reference hypersurface will be defined in this parameter space.

[0122] Any of these methods and devices may be configured for communicating information by the processing unit to the device. The generated diagnostic information may be transmitted from a remote processor (e.g., a PC computer, a server, etc.) to the device memory over a commercial communication network. The methods and devices may also be configured for conveying the diagnostic information to the patient by the device. The received diagnostic information may be presented to the user in the form of a characteristic sound, voice, graphic, or text.

[0123] Additionally, an approximate conventional 12-lead ECG signal may be sent to the user's physician for evaluation. By transforming the three special cardiac lead signals recorded by the user, this signal may be generated as an approximate conventional 12-lead reconstruction. This reconstruction is obtained by multiplying the three special cardiac leads by a 12×3 matrix. In one embodiment, this matrix may be obtained in a computer by using a general solution of the distribution of electrical potentials on the surface of the human body, similar to that described above for the definition of a conventional vector electrocardiogram. In another embodiment, this matrix may be obtained as a population matrix, which is a matrix with coefficients calculated as the mean or median of individual matrices obtained by simultaneously recording a conventional 12-lead ECG and the three special cardiac leads in a population of individuals, each individual matrix being determined using a least squares method. In yet another embodiment, multiple matrices may be used with corresponding user groups defined by simple parameters of body shape and structure such as sex, height, weight, chest circumference, etc., which may be easily obtained by the user. The matrix coefficients may also be determined as continuous functions of such body parameters.

[0124] Equipment arrangement The optimal placement of the three-lead mobile cardiac monitoring device having the first compact undeployed configuration and the second deployed configuration described herein is on the chest with the center of the device on the left side of the chest approximately above the center of the myocardium. In this position, the right edge of the device is approximately 3 cm away from the midsternal line, which is the vertical midline of the sternum, and the lower edge of the device is approximately at the level of the lower edge of the sternum. In an ideal case, the user selects the optimal position on the chest for the initial baseline recording and repeats this position for each future diagnostic recording. In this situation, cardiac recordings are repeatable and cardiac signal changes indicative of AMI are easy to detect.

[0125] Risk Assessment Methodology A risk assessment model for determining the probability that a patient has a serious condition such as acute myocardial infarction (AMI) or cardiac ischemia is based on three types of input data: a) the patient's risk factors, b) cardiac signal recordings, and c) current symptom data.

[0126] The evaluation method may include the following steps: 1) input of risk factor data by the patient himself and storing the data in the system memory, 2) automatic recording of a 3-lead ECG by the patient using the handheld device, 3) input of current symptom data by the patient himself, 4) sending of cardiac signal and current symptom data to a remote processor / server, 5) processing of the data in the processor / server, 6) sending of a diagnostic message to the handheld device, and 7) communicating the diagnostic message to the patient using a graphical or voice interface of the handheld device. Step 1 is performed during the first use of the device / system by the patient. Steps 2-7 are performed when the patient has symptoms or wishes to perform a cardiac screening. The diagnostic message refers to calling for emergency services, waiting until another measurement, or ignoring the symptoms. In other words, the message has the form of an instruction to the patient on what action to take.

[0127] In some embodiments, the automatic diagnostic system is based on cardiac risk assessment using three risk components: cardiac signal risk (CSR), pre-existing risk (PER - patient risk factors stored in memory), and chest pain risk (CPR - current symptoms risk). Each risk is described with three risk levels: H - high, I - medium, and L - low. The cardiac risk decision value is used to select the diagnostic message to be delivered to the patient.

[0128] The final diagnostic message to the patient is given after up to three repeated diagnostic sessions, 5-10 minutes apart. Each diagnostic session consists of a cardiac recording and a Chest Pain Questionnaire (CPQ).

[0129] Cardiac Signal Risk (CSR) Cardiac signal risk assessment may include three cardiac leads, which are nearly orthogonal and store most of the diagnostic information present in a conventional 12-lead ECG. Each user may be enrolled in the diagnostic system by performing an initial transmission of an asymptomatic cardiac recording with three cardiac leads. This initial recording may be used as a reference recording for AMI detection in diagnostic recordings (which represent further recordings of the three cardiac leads for the same user). Availability of a reference cardiac recording allows differentiation between old and new STE (ST segment elevation) and other cardiac signal changes suggestive of AMI.

[0130] STE is the most common ECG change in cases of ischemia, usually measured at the J point or up to 80 ms later. In this solution, ischemic changes are detected by comparing the diagnostic recording with the baseline recording. In a preferred embodiment, the parameter or "marker" for ischemia detection is STVM, and the vector magnitude of the difference signal ΔD* at 80 ms after the J point (J+80 ms) represents the change between the baseline and diagnostic three cardiac lead vectors. The difference signal ΔD* is calculated (as above) as Equation (4):

number

[0131] D* is the diagnostic three-lead cardiac vector and B* is the reference three-lead cardiac vector.

[0132] In other embodiments, vector magnitudes at other time points may be used as markers for ischemia, such as the J point, J+60 ms, Tmax, etc. Other markers indicative of the shape of the ST segment (the segment of the ECG signal between the J and J+80 ms points or similar segments) may be used. Such a marker is the "clew", which is defined as the radius of a sphere that encloses the vector signal between the J and J+80 ms points. Other composite markers may also be used, such as logistic regression using a linear combination of STVM and clew markers.

[0133] In some embodiments, the automatic detection of cardiac signal signs of ischemia may be based only on diagnostic recordings, without the use of reference recordings. This approach is used in cases where the patient is not an owner of an automatic device, and therefore reference recordings are not stored in the device's memory. In this case, B* (reference cardiac 3-lead vector) may simply be set to zero.

[0134] In some embodiments, the automatic detection of cardiac signal signs of ischemia may be based on a conventional approach, where the main signs of ischemia are ST segment shift and T wave inversion. These parameters or "markers" of ischemia are defined on a conventional 12-lead ECG. A conventional 12-lead ECG may be synthesized from three orthogonal leads by using a matrix transformation using individual or population reference matrices.

[0135] The thresholds for classifying CSR (H-high, I-medium, L-low) are defined as follows: H-When the CSR marker value is above a threshold (TH2), which may correspond to the criteria for STEMI based on a 12-lead ECG, such as 0.2 mV. I-When the CSR marker value is between TH1 and TH2, such that TH1 may be the optimal threshold for separating AMI and non-AMI signals, such as 0.1 mV. L-When the CSR marker value is below TH1.

[0136] The thresholds TH1 and TH2 may be determined from prior experience and medical literature, or may be optimized using cardiac signal recordings from a clinical data set.

[0137] Existing Risk (PER): (H-High, I-Medium, L-Low) In some variations, the pre-existing risk (PER) determination algorithm is based on the 2013 ACC / AHA Index for the Assessment of Cardiovascular Risk. Variables with statistical merit for inclusion in the risk assessment equation were age, total cholesterol, high-density lipoprotein cholesterol, systolic BP (including treated or untreated status), diabetes mellitus (diabetes), and current smoking status. The cut-off between low (L for <5%), intermediate (I for 5-10%), and high (H for >10%) risk levels is the estimated 10-year risk of cardiovascular disease (ASCVD) events. For the calculation of the pre-existing risk (PER) variable, a "pooled cohort equation" of exponential type is used.

number

[0138] The variable IndividualSum may be calculated as a linear combination of the individual risk factors. IndividualSum =C1*In(age)+C3*In(total cholesterol)+C4*In(age)*In(total cholesterol)+C5*In(HDL)+C6*In(age)*In(HDL)+C7*Post-treatment systolic BP*In(systolic BP)+In(HDL)+C9*(1-Post-treatment systolic BP)*In(systolic BP)+C11*smoker-C12*In(age)*smoker+C13*diabetes

[0139] The coefficients C1-C13 and corresponding risk factor values ​​may be used with corresponding predefined values ​​(such as, but not limited to, those set forth in Goff DC Jr, Lloyd-Jones DM, Bennett G et al., 2013 ACC / AHA guideline on the assessment of cardiovascular risk: a report of the American College of Cardiology / American Heart Association Task Force on Practice Guidelines. Circulation 2014:129(2):S49-S73, which is incorporated herein by reference in its entirety). Alternative scores may also be used for pre-existing risk (PER) assessment.

[0140] Chest Pain Risk (CPR): (H-High, I-Medium, L-Low) At the time of cardiac symptom occurrence, the chest pain risk (CPR-Current Symptom Risk) parameter is manually entered by the patient via keyboard or touch screen. The chest pain risk parameter is chosen based on literature data and the inventors' own clinical experience.

[0141] In a preferred embodiment, a nine parameter questionnaire list may be used as shown in Figure 13. As also shown in Figure 13, each answer to the questionnaire is assigned a certain number of points between -1 and 3. The value of the CPR variable is calculated as the sum of the points for all nine parameter questionnaires.

[0142] CPR risk levels are estimated with cutoffs between low (L for <2 points), intermediate (I for 2-5 points), and high (H for >5 points) risk levels.

[0143] In other embodiments, alternative questions / answers, point numbers, or cutoff values ​​may be used.

[0144] Post-test AMI risk (PTR): (H-high, I-medium, L-low) The post-test AMI risk (PTR) assessment can have three levels (H-high, I-medium, L-low) based on the use of three risk components: cardiac signal risk (CSR), pre-existing risk (PER), and chest pain risk (CPR). There are 27 possible combinations of CSR, PER, and CPR values. The PTR values ​​for each of these combinations are established based on literature data and the inventor's own clinical experience. The values ​​of all 27 possible combinations and the corresponding PTR values ​​are listed in Figure 14.

[0145] Diagnostic report (message) A diagnostic report is given to the patient after completing the diagnostic evaluation which may have 1, 2 or 3 diagnostic sessions (cardiac signal recording and completion of chest pain questionnaire) performed by the patient at predefined time intervals such as 3 sessions with a time interval of 5-10 minutes.

[0146] The diagnostic report given to the patient consists of various diagnostic messages suggesting actions the patient should take. For example, the diagnostic messages may suggest that the patient seek medical care immediately or get reassurance regarding the benign nature of the symptoms. In a preferred embodiment, there are six possible messages: (1) The diagnostic system indicates that you are having a heart attack. Call emergency services immediately. (2) The diagnostic system indicates that you have a high probability of having a heart attack. You should call emergency services and go to the emergency room. (2A) You may be having angina. Try to relax in a quiet place, take nitroglycerine and repeat the recording in 5 minutes. If the pain gets worse and lasts longer than your usual angina, call emergency services. (3) Chest pain attack may be a sign of a heart problem. Notify your doctor and discuss whether further testing is needed. If the pain returns, call emergency services. (3A) The diagnostic system indicates that you are having an angina attack. The diagnostic system evaluation results in the pain resolving and the ECG returning to normal. If the attack feels like regular angina, no emergency action is needed. If the pattern of your angina (severity, frequency, duration of pain) changes, you should notify your doctor immediately. (4) Based on the diagnostic system evaluation, your chest pain is most likely not cardiac related. You should mention this to your doctor at your next appointment. If the pain persists, you are free to decide whether to seek medical care.

[0147] Messages 2A and 3A are used only for patients experiencing angina, as reported when completing the Pre-Existing Risk (PER) questionnaire.

[0148] The diagnostic evaluation by default has three sessions. The diagnostic evaluation may be completed in fewer than three sessions if the diagnostic evaluation termination conditions are met.

[0149] In a preferred embodiment, a diagnostic message is selected based on PTR (post-test risk), CSR (cardiac signal risk), presence of chest pain, pre-existing angina, and the following set of rules:

[0150] Decision Rules 1. If the scores in the first, second, and third sessions are CSR = H, end the diagnostic evaluation and issue Message 1. 2. If the scores in the first, second, and third sessions are PTR = H and CSR < H, end the diagnostic evaluation and issue Message 2. 3. When the number of completed sessions is less than 3 and the score is PTR < H, send a request for an additional session. 4. After the third session, if PTR = I in any of the sessions and CP = 1 (persistence of chest pain) in the third session, Message 2 is issued. 5. After the third session, if PTR = I in any of the sessions and CP = 0 (cessation of chest pain) in the third session, (for non-angina patients only) Message 3 is issued. 6. After the third session, if PTR = L in all three sessions and CP = 0 (cessation of chest pain) or CP = 1 (persistence of chest pain) in the third session, issue Message 4. 7. For angina patients, if the score in the first or second session is PTR = H and CSR < H, issue Message 2A. 8. For angina patients, if the score in the third session is CSR = I or CSR = H and CP = 0 (cessation of chest pain), issue Message 3. 9. For angina patients, if the score is PTR = I or PTR = H in either the first or second session and CSR = L and CP = 0 in the third session, issue Message 3A.

[0151] Figure 15 shows a flowchart of an algorithm based on Rules 1 to 9 described above. The flowchart has two branches for patients with or without angina. Each branch has three recording sessions including possible exits defined by Rules 1 to 2, and the evaluation is based on three recording sessions completed according to Rules 3 to 9. Any of the exit algorithms issues Messages 1 to 4 related to AMI evaluation (inside the circles in Figure 15) or Messages 2A and 3A related to angina attacks (inside the rectangles in Figure 15).

[0152] Any of the methods (including the user interface) described herein may be embodied as software, hardware, or firmware and be executable by a processor (such as a computer, tablet, smartphone, etc.), and stores a set of instructions that cause the processor to perform any of the steps including, without limitation, display, communication with the user, analysis, adjustment of parameters (including timing, frequency, intensity, etc.), judgment, warning, and others when executed by the processor, and may be recorded as a non-transitory computer-readable medium.

[0153] When a feature or element is referred to herein as being "on" another feature or element, it is either directly on the other feature or element, or intervening features and / or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. When a feature or element is referred to as being "connected," "attached," or "coupled" to another feature or element, it will be understood that it may be directly connected, attached, or coupled to the other feature or element, or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected," "directly attached," or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or illustrated with respect to one embodiment, the features and elements so described or illustrated may apply to other embodiments as well. Those skilled in the art will also recognize that a reference to a structure or feature being disposed "adjacent" to another feature may have portions that are above or below the adjacent feature.

[0154] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and / or "comprising", as used herein, specify the presence of stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated by " / ".

[0155] Spatially relative terms such as "under," "below," "lower," "over," "upper," and the like, may be used to facilitate the description of the relationship of one element or feature to another element or feature depicted in the figures. It will be understood that the spatially relative terms are intended to encompass various orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were inverted, an element described as "under" or "beneath" the other element or feature would then be oriented "over" the other element or feature. Thus, the exemplary term "under" can encompass both an orientation above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly," "downwardly," "vertical," "horizontal," and other terms are used herein for descriptive purposes only, unless expressly stated to the contrary.

[0156] The terms "first" and "second" may be used herein to describe various features / elements, but these features / elements should not be limited by these terms unless the context dictates otherwise. These terms may be used to distinguish one feature / element from another. Thus, a first feature / element described below may be referred to as a second feature / element, and similarly, a second feature / element described below may be referred to as a first feature / element, without departing from the teachings of the present invention.

[0157] Throughout this specification and the claims which follow, unless the context requires otherwise, the words "comprise", "comprises" and "comprising" are to be interpreted as indicating that the various components are employed in a cooperative manner in a method and an article (for example, an apparatus and a method including a composition). For example, it will be understood that the term "comprising" means including any one of the recited elements or steps but not excluding any other elements or steps.

[0158] Generally, it should be understood that any of the apparatuses and methods described herein are inclusive, but alternatively all or subsets of components and / or steps may be exclusive and may be expressed as "consisting of" or alternatively "consisting essentially of" various components, steps, subcomponents, or substeps.

[0159] When used in the specification and claims, including when used in the examples, and unless expressly stated otherwise, all numbers may be construed as if preceded by the words "about" or "approximately," even if these words are not explicitly stated. When the words "about" or "approximately" are used in describing a size and / or location, it indicates that the stated value and / or location is within a reasonable expected range of values ​​and / or locations. For example, a numerical value may have a value that is + / -0.1% of the stated value (or range of values), + / -1% of the stated value (or range of values), + / -2% of the stated value (or range of values), + / -5% of the stated value (or range of values), + / -10% of the stated value (or range of values), etc. Any numerical value recited herein should be understood to include about or approximately that value, unless the context indicates otherwise. For example, if a value of "10" is disclosed, then "about 10" is also disclosed. Any numerical ranges described herein are intended to include all subranges subsumed therein. As will be appreciated by those skilled in the art, when a value is disclosed as being "less than or equal to" that value, it is understood that "greater than or equal to that value" and possible ranges between those values ​​are also disclosed. For example, when a value of "X" is disclosed, "less than or equal to X" as well as "greater than or equal to X" (e.g., X is a numerical value) are also disclosed. It is understood that data are provided throughout this application in several different formats and that this data represents a range of any combination of endpoints and starting points and data points. For example, when a specific data point "10" and a specific data point "15" are disclosed, it is understood that greater than 10 and 15, greater than or equal to 10 and 15, less than 10 and 15, less than or equal to 10 and 15, and equal to 10 and 15 are also considered to be disclosed as being between 10 and 15. It is understood that each unit between two specific units is also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0160] Although various exemplary embodiments have been described above, any of a number of modifications may be made to the various embodiments without departing from the scope of the invention as set forth in the claims. For example, the order in which the various method steps described are performed is often changed in alternative embodiments, and one or more method steps may be omitted altogether in other alternative embodiments. Optional features of the various apparatus and system embodiments may be included in some embodiments and not included in other embodiments. Thus, the above description is provided primarily for illustrative purposes and should not be construed as limiting the scope of the invention as set forth in the claims.

[0161] The examples and illustrations contained herein illustrate, by way of example, not limitation, specific embodiments in which the subject matter may be practiced. As noted above, other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of the present disclosure. Such embodiments of the inventive subject matter may be individually or collectively referred to herein by the term "invention" when more than one is actually disclosed, merely for convenience and without any intention of intentionally limiting the scope of the present application to a single invention or inventive concept. Thus, although specific embodiments have been shown and described herein, any mechanism contrived to achieve the same purpose may be substituted for the specific embodiment shown. The present disclosure is intended to encompass any and all modifications or variations of the various embodiments. Combinations of the above embodiments, as well as other embodiments not expressly described herein, will be apparent to those skilled in the art upon reviewing the above description. [Explanation of symbols]

[0162] 1 System 2. Users 3 equipment 4 PC Computer 10. Chassis 12 sides 14 Hand electrode 16 Arm 18 Chest electrode 20 Back 22 Plots 23 Short edge 24 Bottom 26 Side wall 28 Front wall 30 Opening 32 Distal opening 36 Tail section 34 pin 38 Sleeve 40 Coiled Torsion Spring 42 Slots 44 First Tongue 46 Second Tongue 48 Side 55 Tip 56 Sockets 60 Head part 61 Concave Surface 63 Upper side of head 68 Upper side of the tail 72 Bottom side 73 Depression 76 Chamfered part 78 Long edge 700 patients 703 Signal Collector 705,707 Finger electrode 709,711 Chest electrode 800 Signal Collector 804 Orthogonal Lead 806 Mobile telecommunications devices 810 Remote Server

Claims

1. 1. A three-lead mobile cardiac monitoring device comprising: a housing having a front surface and a rear surface; Two chest electrodes; Two finger electrodes; two retractable arms pivotally attached to the housing at opposite ends thereof, the two finger electrodes being disposed on the front or edge of the housing and the two chest electrodes being disposed on the retractable arms; two generally columnar compartments on either side of the housing, each configured to receive the arm in a stowed position, each compartment having two side walls, a bottom, a front wall and a pin, each pin connecting two opposing side walls of each compartment; An apparatus comprising:

2. 2. The device of claim 1, wherein each retractable arm has a recessed tapered portion at one end that accommodates one of the chest electrodes for acquiring signals from the patient's chest.

3. 2. The apparatus of claim 1, wherein each arm includes a torsion spring coaxial with the pin, the springs having first and second tangs, the first tang mating with the arm and the second tang mating with the housing.

4. 2. The device of claim 1, further comprising a pair of compartments and one or more locks for holding each of the arms in a storage position within the compartment of the pair of compartments, each arm having two spring plungers arranged in a vertical cylinder on the side of the arm such that a tip of each plunger is configured to fit into a recess formed in each side wall of the compartment.

5. 2. The device of claim 1, wherein the finger electrodes are disposed on chamfered portions of one or more long edges of the front surface, the chamfered portions being offset relative to a lateral centerline of the front surface, and the arms are disposed adjacent to or on a short edge of the front surface on a longitudinal centerline.

6. 10. The device of claim 1, further comprising a pair of compartments each having an opening adapted to receive a portion of the one or two retractable arms.

7. 10. The device of claim 1, wherein the housing has a length to thickness ratio of about 15 or greater and a length to width ratio of about 1.6 or greater.

8. 10. The device of claim 1, wherein the distance between the chest electrodes in the unretracted position is greater than about 10 cm.

9. The device of claim 1, wherein the angle between the arms in the non-retracted position is approximately 135 degrees.

10. 1. A three-lead mobile cardiac monitoring device having a first compact, undeployed configuration and a second deployed configuration, a housing having a front surface and a rear surface; Two chest electrodes; Two finger electrodes; two retractable arms pivotally attached to said housing at opposite ends; Equipped with the two finger electrodes are disposed on the front or leading edge of the housing and the two chest electrodes are disposed on the retractable arm; the retractable arm retracts flush with the rear surface in the undeployed configuration and extends at an angle relative to the rear surface in the deployed configuration; Device.

11. 11. The device of claim 10, wherein each retractable arm has a recessed tapered portion at one end that accommodates one of the chest electrodes for acquiring signals from the patient's chest.

12. 11. The apparatus of claim 10, further comprising two general compartments on each side of the housing, each configured to receive the arm in a stowed position.

13. 13. The apparatus of claim 12, wherein each arm includes a torsion spring having a first and second tang, the first tang mating with the arm and the second tang mating with the housing.

14. 11. The device of claim 10, further comprising a pair of compartments and one or more locks that hold each of the arms in a storage position within the compartments of the pair of compartments, each arm having two spring plungers arranged in a vertical cylinder on the side of the arm such that a tip of each plunger is configured to fit into a recess formed in each side wall of the compartment.

15. The device of claim 10 , wherein the finger electrodes are disposed on chamfered portions of one or more long edges of the front surface.

16. 16. The device of claim 15, wherein the chamfered portion is offset relative to a lateral centerline of the front face and the arms are disposed adjacent to or at a short edge of the front face on a longitudinal centerline.

17. 11. The device of claim 10, further comprising a pair of compartments each having an opening adapted to receive a portion of the one or two retractable arms.

18. 11. The device of claim 10, wherein the housing has a length to thickness ratio of about 15 or greater and a length to width ratio of about 1.6 or greater.

19. 11. The device of claim 10, wherein the distance between the chest electrodes in the unretracted position is greater than about 10 cm.

20. The device of claim 10, wherein the angle between the arms in the non-stored position is approximately 135 degrees.

21. 1. A method for automatically assessing a patient's risk of an acute cardiac event, comprising: receiving risk assessment information from the patient, the risk assessment information including risk factors, the risk assessment information being received by a processor; storing an existing risk score based on the risk assessment information; receiving a sample electrocardiogram (ECG) from the patient, the sample ECG being automatically recorded by the patient using a three-lead mobile cardiac monitoring device, and receiving a current symptom indication from the patient; determining, by the processor, an ECG risk score from the sample ECG and the reference ECG and a chest pain risk score based on the current symptom indication, and determining a post-test risk score using the ECG risk score, the pre-existing risk score, and the chest pain risk score; and presenting to the patient a diagnostic report and patient action instructions based on the post-test risk score; The three-lead mobile cardiac monitoring device comprises: a housing having a front surface and a rear surface; Two chest electrodes; Two finger electrodes; two retractable arms pivotally attached to said housing at opposite ends; Equipped with the two finger electrodes are disposed on the front or leading edge of the housing and the two chest electrodes are disposed on the retractable arm; the retractable arm retracts flush with the rear surface in a non-deployed configuration and extends at an angle relative to the rear surface in a deployed configuration; method.

22. 22. The method of claim 21, further comprising deploying the three-lead mobile cardiac monitoring device from the undeployed configuration to the deployed configuration.

23. 22. The method of claim 21, further comprising receiving the reference ECG from the patient by the processor at least 24 hours prior to receiving the sample ECG, the patient acquiring the reference ECG using a handheld device.

24. 22. The method of claim 21, further comprising: said risk factors including age, total cholesterol, HDL, systolic blood pressure, diabetes mellitus status, and current smoking status.

25. 22. The method of claim 21, wherein the pre-existing risk score based on the risk assessment information comprises calculating a weighted sum of the risk factors.

26. 22. The method of claim 21, wherein receiving the sample ECG from the patient includes the patient using the three-lead mobile cardiac monitoring device having a first compact, undeployed configuration and a second deployed configuration, the handheld device having at least four electrodes acquiring three substantially orthogonal leads.

27. 22. The method of claim 21, wherein receiving the current symptom indication from the patient comprises selecting the current symptom indication from a predefined list of symptoms selectable on a handheld device.

28. 28. The method of claim 27, wherein the selecting comprises selecting the current symptom indication from a user interface of the handheld device.

29. 22. The method of claim 21, wherein determining the ECG risk score comprises indicating risk as being high (H), intermediate (I), or low (L).

30. 22. The method of claim 21, wherein determining the chest pain risk score comprises indicating a risk that is high (H), medium (I), or low (L).

31. 22. The method of claim 21, wherein determining the post-test risk score comprises applying a look-up table indexed by the ECG risk score, the chest pain risk score, and a pre-existing risk score.

32. 22. The method of claim 21, wherein the steps of accepting the sample ECG and the current symptom indication are repeated prior to determining the ECG risk score.

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