US20210186404A1 - Wearable electrocardiography and physiology monitoring ensemble - Google Patents

Abstract

A wearable electrocardiography monitoring ensemble is provided. At least one internal structure is formed within a garment and defined by two horizontal bands across a front surface of the garment. An electrode assembly is positioned within the internal structure and includes at least one electrode to sense cardiac electric signals. An electrical connection is connected on one end to one of the electrodes and interfaced on an other end to a monitor recorder that records the cardiac electric signals. The internal structure exerts against a top surface of the electrode assembly a compressive force that presses the electrode assembly against a wearer's skin.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This non-provisional patent application is a continuation of U.S. patent application Ser. No. 16/378,458, filed Apr. 8, 2019, pending, which is a continuation of U.S. Pat. No. 10,251,575, issued Apr. 9, 2019, which is a continuation of U.S. Pat. No. 9,655,537, issued May 23, 2017, which is a continuation-in-part of U.S. Pat. No. 9,717,432, issued Aug. 1, 2017, which is a continuation-in-part of U.S. Pat. No. 9,545,204, issued Jan. 17, 2017, and further claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent application, Ser. No. 61/882,403, filed Sep. 25, 2013, the disclosures of which are incorporated by reference.
FIELD
• This application relates in general to electrocardiography and physiology monitoring and, in particular, to a wearable electrocardiography and physiology monitoring ensemble.
BACKGROUND
• An electrocardiogram (ECG) measures and records electrical potential signals and visually depicts heart electrical activity over time. Conventionally, a standard 12-lead configuration is used in-clinic to record cardiac electrical signals from established chest locations. Physicians use ECGs to diagnose heart problems and other health concerns during appointments; however, spot ECG recording may not always detect sporadic conditions, including conditions affected by fluctuations in blood pressure, blood sugar, respiratory function, temperature, cardiac physiology and pathophysiology, or cardiac rhythm.
• Physicians may provide improved diagnoses through ambulatory ECG monitoring that increases the odds of capturing sporadic conditions, during which a subject can also engage in activities of daily living. While long-term extended ambulatory monitoring in-clinic is implausible and impracticable, diagnostic efficacy can be improved through long-term extended ambulatory ECG monitoring. A 30-day observation period is considered the “gold standard,” but has heretofore proven unworkable because existing ECG monitoring systems have been arduous to employ, cumbersome to the patient, and expensive.
• Extended ECG monitoring is further complicated by patient intolerance to long-term electrode wear and predisposition to skin irritation. Moreover, natural materials from the patient's body, such as hair, sweat, skin oils, and dead skin cells, can get between an electrode, adhesives, and the skin's surface, which can adversely affect electrode contact and cardiac signal recording quality. Patient physical movement and clothing can impart forces on the ECG electrode contact point; inflexibly fastened ECG electrodes are particularly prone to becoming dislodged. Precisely re-placing a dislodged ECG electrode may be essential to ensuring signal capture at the same fidelity. Dislodgment may occur unbeknownst to the patient, rendering the ECG recordings worthless.
• The high cost of the patient-wearable components used to provide long-term extended ECG monitoring can also negatively influence the availability and use of monitors. Disposable components, such as adhesive electrodes, ideally should be inexpensive, while more complex components, particularly the electronic hardware that detects and records ECG and related physiological data, may be unavoidably expensive. Costs can be balanced by designing the electric hardware to be re-usable, but when the total cost of a full ECG monitoring ensemble remains high, despite the utilization of re-usable parts, the number of monitors available for use by healthcare providers can be inhibited. Cost, then, becomes a barrier to entry, which, in turn, can hinder or prevent healthcare providers from obtaining the means with which to efficaciously identify the physiology underlying sporadic cardiac arrhythmic conditions and can ultimately contribute to a failure to make proper and timely medical diagnose.
• ECG data are crucial for diagnosing many cardiovascular conditions. For example, detecting abnormal respiratory function with ECG data showing normal respiratory variation may facilitate diagnosis, prognosis, and treatment of certain disorders. Moreover, ECG data obtained through ambulatory monitoring, when combined with additional physiological data, can be especially helpful when diagnosing athletes, who present unique concerns not generally observed in a non-physically active patient population. For example, blood sugar plays a strong role in athletic performance and recovery and correlates with cardiac function. Monitoring respiratory and ECG together can help in diagnosing cardiorespiratory conditions common to athletes, especially since such conditions not only impair performance, but when combined with overtraining, a cardiorespiratory impairment may lead to severe or even terminal conditions, including severe bronchoconstriction or sudden death.
• Existing portable devices that monitor cardiac data and other physiological data, at best, provide suboptimal results. Such devices can be inconvenient and may restrain movement; for example, a Holter device, which is a wearable ECG monitor with leads placed in a similar position as used with a standard ECG set-up, is cumbersome, expensive, typically only available by medical prescription, and requires skilled medical staff to properly position the electrodes.
• Wrist monitors, such as the Fitbit product line of activity trackers, manufactured by Fitbit Inc., San Francisco, Calif., and related technologies, like wristwatch smartphones (also known as smartwatches), such as the Apple Watch, manufactured by Apple Inc., Cupertino, Calif. or the Gear S smartwatch, manufactured by Samsung Electronics Co., Ltd., Suwon, South Korea, as well as clothing embedded with sensors, such as the Hexoskin product line of wearable clothing, manufactured by Cane Technologies, Inc., Montreal, Quebec, Canada, all experience fidelity problems related to variation in electrode and sensor contact. Gaps in signal quality or interruptions or distortions of the data stream can lead to false positives and false negatives critical to understanding the relationship between physiological markers and medical events or needs.
• U.S. Pat. No. 8,668,653, to Nagata, et al., discloses an ECG-monitoring shirt with a plurality of electrodes, including four limb electrodes and sensors disposed on a beltline. To fit each of the electrodes on the body surface of the examinee, a low-irritant acrylic adhesive, for example, may be applied on each of the electrodes that fit on the body's surface. The use of adhered electrodes is incompatible in patients with a predisposition to skin irritation.
• Therefore, a need remains for an ambulatory, extended-wear monitor that can be used by patients who are intolerant to adhesively-adhered electrodes; highly mobile individuals, such as athletes, whose movement will cause adhesively-adhered electrodes to become dislodged; and individuals of all types in whom the recording high-quality PQRSTU ECG data and related physiological data are desired.
SUMMARY
• Long-term extended ECG monitoring can be provided through a form of ECG or physiological sensor embedded into clothing, rather than on the-skin electrodes. The garment is made of a material holding the sensor in place during extended wear through, for example, a compressible, breathable fabric. Electrodes are preferably placed on the garment to contact the skin along a wearer's sternal midline at specific positions to enhance P-wave detection and ECG. The electrodes are connected to an ECG monitor recorder that is either discrete from or affixed to the garment and obtains physiological telemetry through a wireless or electrical interface. Various types of physiological sensors can be provided.
• One embodiment provides a wearable electrocardiography monitoring ensemble. At least one internal structure is formed within a garment and defined by two horizontal bands across a front surface of the garment. An electrode assembly is positioned within the internal structure and includes at least one electrode to sense cardiac electric signals. An electrical connection is connected on one end to one of the electrodes and interfaced on an other end to a monitor recorder that records the cardiac electric signals. The internal structure exerts against a top surface of the electrode assembly a compressive force that presses the electrode assembly against a wearer's skin.
• The wearable monitoring ensemble creates a more natural experience for wearers and can be used to produce an expanded dataset for diagnosis because the ensemble can collect data during activities of daily living and can capture cardiovascular events outside of clinical observation, which is otherwise not practicable, especially for athletes.
• Still other embodiments will become readily apparent to those skilled in the art from the following detailed description, wherein are described embodiments by way of illustrating the best mode contemplated. As will be realized, other and different embodiments are possible, and the embodiments' several details are capable of modifications in various obvious respects, all without departing from their spirit and the scope. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIGS. 1 and 2 are diagrams showing, by way of examples, an extended wear electrocardiography monitor, including an extended wear electrode patch in accordance with one embodiment, respectively fitted to the sternal region of a female and a male.
• FIG. 3 is a perspective view showing an extended wear electrode patch in accordance with one embodiment with a monitor recorder inserted.
• FIG. 4 is a perspective view showing the extended wear electrode patch ofFIG. 3 without a monitor recorder inserted.
• FIG. 5 is a top view showing the flexible circuit of the extended wear electrode patch ofFIG. 3.
• FIG. 6 is a perspective view showing the extended wear electrode patch in accordance with a further embodiment.
• FIG. 7 is an exploded view showing the component layers of the electrode patch ofFIG. 3.
• FIG. 8 is a bottom plan view of the extended wear electrode patch ofFIG. 3 with liner partially peeled back.
• FIG. 9 is a perspective view of an extended wear electrode patch with a flexile wire electrode assembly in accordance with a still further embodiment.
• FIG. 10 is perspective view of the flexile wire electrode assembly fromFIG. 9, with a layer of insulating material shielding a bare distal wire around the midsection of the flexible backing.
• FIG. 11 is a bottom view of the flexile wire electrode assembly as shown inFIG. 9.
• FIG. 12 is a bottom view of a flexile wire electrode assembly in accordance with a still yet further embodiment.
• FIG. 13 is a perspective view showing the longitudinal midsection of the flexible backing of the electrode assembly fromFIG. 9.
• FIG. 14 is a longitudinal cross-sectional view of the midsection of the flexible backing of the electrode assembly ofFIG. 11.
• FIGS. 15A-C are the electrode assembly fromFIG. 14 under compressional, tensile, and bending force, respectively.
• FIG. 16 is a flow diagram showing a method for constructing a stress-pliant physiological electrode assembly in accordance with a further embodiment.
• FIG. 17 is a front view of a wearable electrocardiography and physiology monitoring ensemble in accordance with a further embodiment.
• FIG. 18 is a contact-surface view of a flexible circuit electrode assembly of the wearable monitoring ensemble ofFIG. 17.
• FIG. 19 is a contact-surface view of a flexile wire interconnect of the wearable monitoring ensemble ofFIG. 17.
• FIG. 20 is a contact-surface view of a flexile wire electrode and interconnect of the wearable monitoring ensemble ofFIG. 17.
DETAILED DESCRIPTION
• Physiology monitoring can be provided through a wearable monitor that includes two components, a flexible extended wear electrode patch and a removable reusable monitor recorder.FIGS. 1 and 2 are diagrams showing, by way of examples, an extendedwear electrocardiography monitor12, including an extendedwear electrode patch15 in accordance with one embodiment, respectively fitted to the sternal region of a female10 and a male11. In a further embodiment, extended wear monitoring can be provided in the form of a wearable garment, as further described below beginning with reference toFIG. 17 et seq. Thewearable monitor12 sits centrally (in the midline) on a human chest along thesternum13 oriented top-to-bottom with themonitor recorder14 preferably situated towards a human head. Theelectrode patch15 is shaped to fit comfortably and conform to the contours of a human chest approximately centered on the sternal midline16 (or immediately to either side of the sternum13). The distal end of theelectrode patch15 extends towards the Xiphoid process and lower sternum and, depending upon a human build, may straddle the region over the Xiphoid process and lower sternum. The proximal end of theelectrode patch15, located under themonitor recorder14, is below the manubrium and, depending upon a person's build, may straddle the region over the manubrium.
• The placement of thewearable monitor12 in a location at the sternal midline16 (or immediately to either side of the sternum13) significantly improves the ability of thewearable monitor12 to cutaneously sense cardiac electric signals, particularly the P-wave (or atrial activity) and, to a lesser extent, the QRS interval signals in the ECG waveforms that indicate ventricular activity. Thesternum13 overlies the right atrium of the heart and the placement of thewearable monitor12 in the region of thesternal midline13 puts the ECG electrodes of theelectrode patch15 in a location better adapted to sensing and recording P-wave signals than other placement locations, say, the upper left pectoral region. In addition, placing the lower or inferior pole (ECG electrode) of theelectrode patch15 over (or near) the Xiphoid process and lower sternum facilitates sensing of right ventricular activity and provides superior recordation of the QRS interval.
• During use, theelectrode patch15 is first adhered to the skin along the sternal midline16 (or immediately to either side of the sternum13). Amonitor recorder14 is then snapped into place on theelectrode patch15 to initiate ECG monitoring.FIG. 3 is a perspective view showing an extendedwear electrode patch15 in accordance with one embodiment with amonitor recorder14 inserted. The body of theelectrode patch15 is preferably constructed using aflexible backing20 formed as anelongated strip21 of wrap knit or similar stretchable material about 145 mm long and 32 mm at the widest point with a narrow longitudinal mid-section23 evenly tapering inward from both sides. A pair of cut-outs22 between the distal and proximal ends of theelectrode patch15 create a narrowlongitudinal midsection23 or “isthmus” and defines an elongated “hourglass”-like shape, when viewed from above, such as described in commonly-assigned U.S. Pat. No. D744,659, issued Dec. 1, 2015, the disclosure of which is incorporated by reference. The upper part of the “hourglass” is sized to allow an electricallynon-conductive receptacle25, sits on top of the outward-facing surface of theelectrode patch15, to be affixed to theelectrode patch15 with an ECG electrode placed underneath on the wearer-facing underside, or contact, surface of theelectrode patch15; the upper part of the “hourglass” has a longer and wider profile than the lower part of the “hourglass,” which is sized primarily to allow just the placement of an ECG electrode.
• Theelectrode patch15 incorporates features that significantly improve wearability, performance, and comfort throughout an extended monitoring period. Theentire electrode patch15 is lightweight in construction, which reduces shear forces and allows the patch to be resilient to disadhesing, displacement, or falling off and, critically, to avoid creating distracting discomfort, even when a person is asleep. In contrast, the weight of a heavy ECG monitor impedes wearer mobility and will cause the monitor to constantly tug downwards and press on the wearer's body; frequent adjustments by the wearer are needed to maintain comfort.
• During every day wear, theelectrode patch15 is subjected to pushing, pulling, and torsional movements, including compressional and torsional forces when the wearer bends forward, and tensile and torsional forces when the wearer leans backwards. To counter these stress forces, theelectrode patch15 incorporates crimp and strain reliefs, as further described infra respectively with reference toFIGS. 4 and 5. In addition, the cut-outs22 andlongitudinal midsection23 help minimize interference with and discomfort to breast tissue, particularly in women (and gynecomastic men). The cut-outs22 andlongitudinal midsection23 allow better conformity of theelectrode patch15 to sternal bowing and to the narrow isthmus of flat skin that can occur along the bottom of the intermammary cleft between the breasts, especially in buxom women. The cut-outs22 andlongitudinal midsection23 help theelectrode patch15 fit nicely between a pair of female breasts in the intermammary cleft. In one embodiment, the cut-outs22 can be graduated to form thelongitudinal midsection23 as a narrow in-between stem or isthmus portion about 7 mm wide. In a still further embodiment,tabs24 can respectively extend an additional 8 mm to 12 mm beyond the distal and proximal ends of theflexible backing20 to facilitate purchase when adhering theelectrode patch15 to or removing theelectrode patch15 from thesternum13. These tabs preferably lack adhesive on the underside, or contact, surface of theelectrode patch15. Still other shapes, cut-outs and conformities to theelectrode patch15 are possible.
• Themonitor recorder14 removably and reusably snaps into an electricallynon-conductive receptacle25 during use. Themonitor recorder14 contains electronic circuitry for recording and storing the wearer's electrocardiography as sensed via a pair of ECG electrodes provided on theelectrode patch15, such as described in commonly-assigned U.S. Pat. No. 9,730,593, the disclosure of which is incorporated by reference. The circuitry includes a microcontroller, flash storage, ECG signal processing, analog-to-digital conversion (where applicable), and an external interface for coupling to theelectrode patch15 and to a download station for stored data download and device programming. Themonitor recorder14 also includes external wearer-interfaceable controls, such as a push button to facilitate event marking and provide feedback. In a further embodiment, the circuitry, with the assistance of the appropriate types of deployed electrodes or sensors, is capable of monitoring other types of physiology, in addition to ECGs. Still other types of monitor recorder components and functionality are possible.
• Thenon-conductive receptacle25 is provided on the top surface of theflexible backing20 with aretention catch26 andtension clip27 molded into thenon-conductive receptacle25 to conformably receive and securely hold themonitor recorder14 in place. The edges of the bottom surface of thenon-conductive receptacle25 are preferably rounded, and themonitor recorder14 is nestled inside the interior of thenon-conductive receptacle25 to present a rounded (gentle) surface, rather than a sharp edge at the skin-to-device interface.
• Theelectrode patch15 is intended to be disposable. Themonitor recorder14, however, is reusable and can be transferred tosuccessive electrode patches15 to ensure continuity of monitoring. The placement of thewearable monitor12 in a location at the sternal midline16 (or immediately to either side of the sternum13) benefits long-term extended wear by removing the requirement that ECG electrodes be continually placed in the same spots on the skin throughout the monitoring period. Instead, the wearer is free to place anelectrode patch15 anywhere within the general region of thesternum13.
• As a result, at any point during ECG monitoring, the wearer's skin is able to recover from the wearing of anelectrode patch15, which increases wearer comfort and satisfaction, while themonitor recorder14 ensures ECG monitoring continuity with minimal effort. Amonitor recorder14 is merely unsnapped from a worn outelectrode patch15, the worn outelectrode patch15 is removed from the skin, anew electrode patch15 is adhered to the skin, possibly in a new spot immediately adjacent to the earlier location, and thesame monitor recorder14 is snapped into thenew electrode patch15 to reinitiate and continue the ECG monitoring.
• During use, theelectrode patch15 is first adhered to the skin in the sternal region.FIG. 4 is a perspective view showing the extendedwear electrode patch15 ofFIG. 3 without amonitor recorder14 inserted. Aflexible circuit32 is adhered to each end of theflexible backing20. Adistal circuit trace33 from thedistal end30 of theflexible backing20 and a proximal circuit trace (not shown) from theproximal end31 of theflexible backing20 electrically couple ECG electrodes (not shown) with a pair ofelectrical pads34. In a further embodiment, the distal and proximal circuit traces are replaced with interlaced or sewn-in flexible wires, as further described infra beginning with reference toFIG. 9. Theelectrical pads34 are provided within a moisture-resistant seal35 formed on the bottom surface of thenon-conductive receptacle25. When themonitor recorder14 is securely received into thenon-conductive receptacle25, that is, snapped into place, theelectrical pads34 interface to electrical contacts (not shown) protruding from the bottom surface of themonitor recorder14. The moisture-resistant seal35 enables themonitor recorder14 to be worn at all times, even during bathing or other activities that could expose themonitor recorder14 to moisture or adverse conditions.
• In addition, abattery compartment36 is formed on the bottom surface of thenon-conductive receptacle25. A pair of battery leads (not shown) from thebattery compartment36 to another pair of theelectrical pads34 electrically interface the battery to themonitor recorder14. The battery contained within thebattery compartment35 can be replaceable, rechargeable or disposable.
• Themonitor recorder14 draws power externally from the battery provided in thenon-conductive receptacle25, thereby uniquely obviating the need for themonitor recorder14 to carry a dedicated power source. The battery contained within thebattery compartment36 can be replaceable, rechargeable or disposable. In a further embodiment, the ECG sensing circuitry of themonitor recorder14 can be supplemented with additional sensors, including an SpO2 sensor, a blood pressure sensor, a temperature sensor, respiratory rate sensor, a glucose sensor, an air flow sensor, and a volumetric pressure sensor, which can be incorporated directly into themonitor recorder14 or onto thenon-conductive receptacle25.
• The placement of theflexible backing20 on the sternal midline16 (or immediately to either side of the sternum13) also helps to minimize the side-to-side movement of thewearable monitor12 in the left- and right-handed directions during wear. However, thewearable monitor12 is still susceptible to pushing, pulling, and torqueing movements, including compressional and torsional forces when the wearer bends forward, and tensile and torsional forces when the wearer leans backwards. To counter the dislodgment of theflexible backing20 due to compressional and torsional forces, a layer of non-irritating adhesive, such as hydrocolloid, is provided at least partially on the underside, or contact, surface of theflexible backing20, but only on thedistal end30 and theproximal end31. As a result, the underside, or contact surface of thelongitudinal midsection23 does not have an adhesive layer and remains free to move relative to the skin. Thus, thelongitudinal midsection23 forms a crimp relief that respectively facilitates compression and twisting of theflexible backing20 in response to compressional and torsional forces. Other forms of flexible backing crimp reliefs are possible.
• Unlike theflexible backing20, theflexible circuit32 is only able to bend and cannot stretch in a planar direction.FIG. 5 is a top view showing theflexible circuit32 of the extendedwear electrode patch15 ofFIG. 3. Adistal ECG electrode38 andproximal ECG electrode39 are respectively coupled to the distal and proximal ends of theflexible circuit32 to serve as electrode signal pickups. Theflexible circuit32 preferably does not extend to the outside edges of theflexible backing20, thereby avoiding gouging or discomforting the wearer's skin during extended wear, such as when sleeping on the side. During wear, theECG electrodes38,39 must remain in continual contact with the skin. Astrain relief40 is defined in theflexible circuit32 at a location that is partially underneath thebattery compartment36 when theflexible circuit32 is affixed to theflexible backing20. Thestrain relief40 is laterally extendable to counter dislodgment of theECG electrodes38,39 due to tensile and torsional forces. A pair ofstrain relief cutouts41 partially extend transversely from each opposite side of theflexible circuit32 and continue longitudinally towards each other to define in ‘S’-shaped pattern, when viewed from above. The strain relief respectively facilitates longitudinal extension and twisting of theflexible circuit32 in response to tensile and torsional forces. Other forms of circuit board strain relief are possible.
• Theflexible circuit32 can be provided either above or below theflexible backing20.FIG. 6 is a perspective view showing the extendedwear electrode patch15 in accordance with a further embodiment. The flexible circuit (not shown) is provided on the underside, or contact, surface of theflexible backing20 and is electrically interfaced to the set ofelectrical pads34 on the bottom surface of thenon-conductive receptacle25 through electrical contacts (not shown) pierced through theflexible backing20.
• Theelectrode patch15 is intended to be a disposable component, which enables a wearer to replace theelectrode patch15 as needed throughout the monitoring period, while maintaining continuity of physiological sensing through reuse of thesame monitor recorder14.FIG. 7 is an exploded view showing the component layers of theelectrode patch15 ofFIG. 3. Theflexible backing20 is constructed of a wearable gauze, latex, woven textile, or similar wrap knit or stretchable and wear-safe material44, such as a Tricot-type linen with a pressure sensitive adhesive (PSA) on the underside, or contact, surface. The ends of thewearable material44 are coated with alayer43 of non-irritating adhesive, such as hydrocolloid, to facilitate long-term wear, while the unadhesed narrowed midsection rides freely over the skin. The hydrocolloid, for instance, is typically made of mineral oil, cellulose and water and lacks any chemical solvents, so should cause little itching or irritation. Moreover, hydrocolloid can be manufactured into an appropriate thickness and plasticity and provides cushioning between the relatively rigid and unyieldingnon-conductive receptacle25 and the wearer's skin. In a further embodiment, the layer of non-irritating adhesive can be contoured, such as by forming the adhesive with a concave or convex cross-section; surfaced, such as through stripes or crosshatches of adhesive, or by forming dimples in the adhesive's surface; or applied discontinuously, such as with a formation of discrete dots of adhesive.
• As described supra with reference toFIG. 5, a flexible circuit can be adhered to either the outward facing surface or the underside, or contact, surface of theflexible backing20. For convenience, aflexible circuit47 is shown relative to the outward facing surface of thewearable material44 and is adhered respectively on a distal end by adistal electrode seal45 and on a proximal end by aproximal electrode seal45. In a further embodiment, theflexible circuit47 can be provided on the underside, or contact, surface of thewearable material44. Through the electrode seals, only the distal and proximal ends of theflexible circuit47 are attached to thewearable material44, which enables the strain relief40 (shown inFIG. 5) to respectively longitudinally extend and twist in response to tensile and torsional forces during wear. Similarly, thelayer43 of non-irritating adhesive is provided on the underside, or contact, surface of thewearable material44 only on the proximal and distal ends, which enables the longitudinal midsection23 (shown inFIG. 3) to respectively bow outward and away from thesternum13 or twist in response to compressional and torsional forces during wear.
• A pair ofopenings46 is defined on the distal and proximal ends of thewearable material44 andlayer43 of non-irritating adhesive forECG electrodes38,39 (shown inFIG. 5). Theopenings46 serve as “gel” wells with a layer ofhydrogel41 being used to fill the bottom of each opening46 as a conductive material that aids electrode signal capture. The entire underside, or contact, surface of theflexible backing20 is protected prior to use by aliner layer40 that is peeled away, as shown inFIG. 8.
• Thenon-conductive receptacle25 includes amain body54 that is molded out of polycarbonate, ABS, or an alloy of those two materials to provide a high surface energy to facilitate adhesion of anadhesive seal53. Themain body54 is attached to a battery printedcircuit board52 by theadhesive seal53 and, in turn, the battery printedcircuit board52 is adhered to theflexible circuit47 with an upperflexible circuit seal50. A pair of conductive transferadhesive points51 or, alternatively, soldered connections, or electromechanical connections, including metallic rivets or similar conductive and structurally unifying components, connect the circuit traces33,37 (shown inFIG. 5) of theflexible circuit47 to the battery printedcircuit board52. Themain body54 has aretention catch26 and tension clip27 (shown inFIG. 3) that fixably and securely receive a monitor recorder14 (not shown), and includes a recess within which to circumferentially receive adie cut gasket55, either rubber, urethane foam, or similar suitable material, to provide a moisture resistant seal to the set ofpads34. Other types of design, arrangement, and permutation are possible.
• In a still further embodiment, the flexible circuit32 (shown inFIG. 4) anddistal ECG electrode38 and proximal ECG electrode39 (shown inFIG. 5) are replaced with a pair of interlaced flexile wires. The interlacing of flexile wires through theflexible backing20 reduces both manufacturing costs and environmental impact, as further described infra. The flexible circuit and ECG electrodes are replaced with a pair of flexile wires that serve as both electrode circuit traces and electrode signal pickups.FIG. 9 is a perspective view of an extendedwear electrode patch15 with a flexile wire electrode assembly in accordance with a still further embodiment. Theflexible backing20 maintains the unique narrow “hourglass”-like shape that aids long term extended wear, particularly in women, as described supra with reference toFIG. 3. For clarity, thenon-conductive receptacle25 is omitted to show the exposed battery printedcircuit board62 that is adhered underneath thenon-conductive receptacle25 to theproximal end31 of theflexible backing20. Instead of employing flexible circuits, a pair of flexile wires are separately interlaced or sewn into theflexible backing20 to serve as circuit connections for an anode electrode lead and for a cathode electrode lead.
• To form a distal electrode assembly, adistal wire61 is interlaced into thedistal end30 of theflexible backing20, continues along an axial path through the narrow longitudinal midsection of the elongated strip, and electrically connects to the battery printedcircuit board62 on theproximal end31 of theflexible backing20. Thedistal wire61 is connected to the battery printedcircuit board62 by stripping thedistal wire61 of insulation, if applicable, and interlacing or sewing the uninsulated end of thedistal wire61 directly into an exposedcircuit trace63. The distal wire-to-battery printed circuit board connection can be made, for instance, by back stitching thedistal wire61 back and forth across the edge of the battery printedcircuit board62. Similarly, to form a proximal electrode assembly, a proximal wire (not shown) is interlaced into theproximal end31 of theflexible backing20. The proximal wire is connected to the battery printedcircuit board62 by stripping the proximal wire of insulation, if applicable, and interlacing or sewing the uninsulated end of the proximal wire directly into an exposedcircuit trace64. The resulting flexile wire connections both establish electrical connections and help to affix the battery printedcircuit board62 to theflexible backing20.
• The battery printedcircuit board62 is provided with abattery compartment36. A set ofelectrical pads34 are formed on the battery printedcircuit board62. Theelectrical pads34 electrically interface the battery printedcircuit board62 with amonitor recorder14 when fitted into thenon-conductive receptacle25. Thebattery compartment36 contains aspring65 and aclasp66, or similar assembly, to hold a battery (not shown) in place and electrically interfaces the battery to theelectrical pads34 through a pair battery leads67 for powering theelectrocardiography monitor14. Other types of battery compartment are possible. The battery contained within thebattery compartment36 can be replaceable, rechargeable, or disposable.
• In a yet further embodiment, the circuit board andnon-conductive receptacle25 are replaced by a combined housing that includes a battery compartment and a plurality of electrical pads. The housing can be affixed to the proximal end of the elongated strip through the interlacing or sewing of the flexile wires or other wires or threads.
• The core of the flexile wires may be made from a solid, stranded, or braided conductive metal or metal compounds. In general, a solid wire will be less flexible than a stranded wire with the same total cross-sectional area, but will provide more mechanical rigidity than the stranded wire. The conductive core may be copper, aluminum, silver, or other material. The pair of the flexile wires may be provided as insulated wire. In one embodiment, the flexile wires are made from a magnet wire from Belden Cable, catalogue number8051, with a solid core ofAWG22 with bare copper as conductor material and insulated by polyurethane or nylon. Still other types of flexile wires are possible. In a further embodiment, conductive ink or graphene can be used to print electrical connections, either in combination with or in place of the flexile wires.
• In a still further embodiment, the flexile wires are uninsulated.FIG. 10 is perspective view of the flexile wire electrode assembly fromFIG. 9, with a layer of insulatingmaterial69 shielding a bare uninsulateddistal wire61 around the midsection on the contact side of the flexible backing. On the contact side of the proximal and distal ends of the flexible backing, only the portions of the flexile wires serving as electrode signal pickups are electrically exposed and the rest of the flexile wire on the contact side outside of the proximal and distal ends are shielded from electrical contact. The bare uninsulateddistal wire61 may be insulated using a layer of plastic, rubber-like polymers, or varnish, or by an additional layer of gauze or adhesive (or non-adhesive) gel. The bareuninsulated wire61 on the non-contact side of the flexible backing may be insulated or can simply be left uninsulated.
• Both end portions of the pair of flexile wires are typically placed uninsulated on the contact surface of theflexible backing20 to form a pair of electrode signal pickups.FIG. 11 is a bottom view of the flexile wire electrode assembly as shown inFIG. 9. When adhered to the skin during use, the uninsulated end portions of thedistal wire61 and theproximal wire71 enable themonitor recorder14 to measure dermal electrical potential differentials. At the proximal and distal ends of theflexible backing20, the uninsulated end portions of the flexile wires may be configured into an appropriate pattern to provide an electrode signal pickup, which would typically be a spiral shape formed by guiding the flexile wire along an inwardly spiraling pattern. The surface area of the electrode pickups can also be variable, such as by selectively removing some or all of the insulation on the contact surface. For example, an electrode signal pickup arranged by sewing insulated flexile wire in a spiral pattern could have a crescent-shaped cutout of uninsulated flexile wire facing towards the signal source.
• In a still yet further embodiment, the flexile wires are left freely riding on the contact surfaces on the distal and proximal ends of the flexible backing, rather than being interlaced into the ends of theflexible backing20.FIG. 12 is a bottom view of a flexile wire electrode assembly in accordance with a still yet further embodiment. Thedistal wire61 is interlaced onto the midsection and extends an exposedend portion72 onto thedistal end30. Theproximal wire71 extends an exposedend portion73 onto theproximal end31. Theexposed end portions72 and73, not shielded with insulation, are further embedded within an electricallyconductive adhesive81. The adhesive81 makes contact to skin during use and conducts skin electrical potentials to the monitor recorder14 (not shown) via the flexile wires. The adhesive81 can be formed from electrically conductive, non-irritating adhesive, such as hydrocolloid.
• Thedistal wire61 is interlaced or sewn through the longitudinal midsection of theflexible backing20 and takes the place of theflexible circuit32.FIG. 13 is a perspective view showing the longitudinal midsection of the flexible backing of the electrode assembly fromFIG. 9. Various stitching patterns may be adopted to provide a proper combination of rigidity and flexibility. In simplest form, thedistal wire61 can be manually threaded through a plurality of holes provided at regularly-spaced intervals along an axial path defined between the battery printed circuit board62 (not shown) and thedistal end30 of theflexible backing20. Thedistal wire61 can be threaded through the plurality of holes by stitching the flexile wire as a single “thread.” Other types of stitching patterns or stitching of multiple “threads” could also be used, as well as using a sewing machine or similar device to machine-stitch thedistal wire61 into place, as further described infra. Further, the path of thedistal wire61 need not be limited to a straight line from the distal to the proximal end of theflexible backing20.
• Thedistal wire61 is flexile yet still retains a degree of rigidity that is influenced by wire gauge, composition, stranding, insulation, and stitching pattern. For example, rigidity decreases with wire gauge; and a solid core wire tends to be more rigid than a stranded core of the same gauge. The combination of the flexibility and the rigidity of the portion of thedistal wire61 located on or close to the midsection contributes to the overall strength and wearability of the patch.FIG. 14 is a longitudinal cross-sectional view of the midsection of theflexible backing20 of the electrode assembly ofFIG. 11.FIGS. 15A-C are the electrode assembly fromFIG. 14 under compressional, tensile, and bending force, respectively. The relative sizes of thedistal wire61 andflexible backing20 are not to scale and are exaggerated for purposes of illustration.
• The interlacing of thedistal wire61 through the narrowlongitudinal midsection22 of theflexible backing20 bends thedistal wire61 into a line of rounded stitches that alternate top and bottom, which can be advantageous to long term wearability. First, the tension of the rounded stitches reinforces the planar structure of the narrowlongitudinal midsection22 and spreads a dislodging force impacting on one end of theflexible backing20 to the other end of theflexible backing20. Second, the rounded stitches leave room for stretching, compressing, bending, and twisting, thus increasing the wearability of the patch extendedwear electrode patch15 by facilitating extension, compression, bending, and twisting of the narrowlongitudinal midsection22 in response to tensile, compressional, bending, and torsional forces.
• In a further embodiment, the distal wire and the proximal wire may be stitched or sewn into theflexible backing20. Depending upon the type of stitching used, the distal or proximal wire may use more than one individual wire. For instance, a conventional sewing machine used to stitch fabrics uses a spool of thread and a bobbin, which are both wound with thread that together allow the creation of various stitching patterns, such as the lockstitch. Other type of stitching patterns are possible. Additionally, where more than one “threads” are used for stitching, the flexile wire may constitute all of the “threads,” thereby increasing redundancy of the circuit trace thus formed. Alternatively, just one (or fewer than all) of the threads may be conductive, with the non-conductive threads serving to reinforce the strength of the flexile wire connections andflexible backing20. The additional threads can be made from line, threads, or fabrics of sufficient mechanical strength and do not need to be conductive; alternatively, the same flexile wires can be employed to serve as the additional threads.
• Conventionally, flexible circuits, such as the flexible circuit32 (shown inFIG. 4) that connects thedistal ECG electrode38 and proximal ECG electrode39 (shown inFIG. 5) to the battery printed circuit board62 (shown inFIG. 9), are constructed using subtractive processes. In general, a flexible circuit interconnects electronic components with custom point-to-point circuit traces and is typically constructed by forming the conductive circuit traces on a thin film of insulating polymer. A flexible circuit is not an off-the-shelf component; rather, each flexible circuit is designed with a specific purpose in mind. Changes to a flexible circuit's design will generally require fabricating entirely new flexible circuits, as the physical circuit traces on the polymer film cannot be changed.
• Manufacturing a flexible circuit typically requires the use of sophisticated and specialized tools, coupled with environmentally unfriendly processes, including depositing copper on a polyamide core, etching away unwanted copper with inline etching or an acid bath to retain only the desired conductive circuit traces, and applying a coverlay to the resulting flexible circuit. Significant amounts of hazardous waste are generated by these subtractive processes during the fabrication of each flexible circuit. Properly disposing of such hazardous waste is expensive and adds to the costs of the flexible circuit.
• In the still further embodiment described supra beginning with reference toFIG. 9, the distal and proximal flexile wires replace theflexible circuit32 and enables the electrode assembly to be constructed using additive processes with off-the-shelf, low cost components. The flexile wires serve the triple functions of an electrode signal pickup, electrical circuit trace, and support for structural integrity and malleability of the electrode assembly.
• The general manner of constructing the electrode assembly can be applied to other forms of electronic components in which custom point-to-point circuit traces need to be affixed to a gauze or textile backing, as well as backings made from other materials. The circuit traces are replaced by the interlaced or sewn flexile wires, and the ends of each flexile wire are terminated, as appropriate to the application. The flexile wires may, by example, connect two circuit boards, or connect to an electrical terminal, power source, or electrical component. In addition, flexile wires may be used to replace a printed circuit board entirely, with each flexile wire serving as a form of sewn interconnect between two or more discrete components, including resistors, capacitors, transistors, diodes, operational amplifiers (op amps) and other integrated circuits, and other electronic or electromechanical components.
• By way of illustration, the flexile wires will be described as terminated for use in an electrode assembly, specifically, as terminated on one end to form an electrode signal pickup and on the other end to connect into a circuit board. Constructing the electrode assembly entails interlacing, including manually threading, or machine sewing the flexile, conductive wire through theflexible backing20.FIG. 16 is a flow diagram showing amethod90 for constructing a stress-pliant physiological electrode assembly in accordance with a further embodiment. The method can be performed by a set of industrial machines, including a gauze cutting machine to cut theflexible backing20 to form; a hole punch to cut a plurality of holes provided at regularly-spaced intervals; a stitching or sewing machine to interleave or sew the flexile wire through theflexible backing20; a wire stripper or plasma jet to remove insulation from the flexile wire, when applicable; and a glue or adhesive dispenser to embed or coat electrode signal pickup in hydrocolloid gel or equivalent non-irritating adhesive. Other forms or combinations of industrial machines, including a single purpose-built industrial machine, could be used.
• As an initial step, a backing is cut to shape and, if required, holes are cut at regularly-spaced intervals along an axial path (step91) through which the flexile wire will be interlaced. Holes will need to be cut, for instance, if the flexile wire is to be hand-guided through the backing, or where the backing is cut from a material that is difficult to puncture with a threaded needle, such as used by a sewing machine. In one embodiment, the backing is cut from wearable gauze, latex, woven textile, or similar wrap knit or stretchable and wear-safe material, such as a Tricot-type linen; the resulting backing is flexible and yielding. The backing is also cut into an elongated “hourglass”-like shape, when viewed from above, with a pair of cut-outs and a longitudinal midsection that together help minimize interference with and discomfort to breast tissue, particularly in women (and gynecomastic men), such as described supra with reference toFIG. 3. The backing can be cut into other shapes as appropriate to need. In addition, depending upon the application, other materials could be substituted for the backing. For example, neoprene, such as used in wetsuits, could be used where a high degree of elasticity and ruggedness is desired.
• The flexile wire is then interlaced or sewn into the backing (step92). Interlacing can be performed by a machine that guides the flexile wire through the holes previously cut in the material in a crisscrossed, interwoven, or knitted fashion, as well as by hand. The flexile wire can also be guided through the backing without first cutting holes, provided that the weave of the material is sufficiently loose to allow passage of the flexile wire if the flexile wire is otherwise incapable of passing through the backing without the assistance of a needle or other piercing instrument.
• Alternatively, the flexile wire could be sewn into the backing by using the flexile wire as “thread” that is stitched into place using a needle or similar implement. If a single flexile wire is employed, the stitching will be a line of rounded stitches that alternate top and bottom, as described supra; however, if more than one flexile wire is used, or the stitching pattern requires the use of more than one thread, other forms of conventional machine-stitching patterns could be employed, such as a lockstitch.
• Once completed, the interlacing or sewing of the flexile wire into the backing creates an integrated point-to-point electrical path that takes the place of a custom circuit trace using an additive, rather than subtractive, manufacturing process. The flexile wire can be interlaced or sewn along a straight, curved, or arbitrary path. One flexile wire is required per point-to-point circuit trace. The strength and pliability of the flexile wire reinforces the backing and, in the still further embodiment described supra beginning with reference toFIG. 9, facilitates extension, compression, bending, and twisting of the narrowlongitudinal midsection22 in response to tensile, compressional, bending, and torsional forces. Thus, the path of the flexile wire along the backing can be mapped to take advantage of the strength and reinforcing properties of the flexile wire, which, when interlaced or sewn into the backing, help the backing counter the stresses to which the backing will be subjected when deployed.
• The flexile wire itself may be insulated or bare (step93). When one end of the flexile wire is connected to (or forms) an electrode, particularly a dermal physiology electrode that senses electrical potentials on the skin's surface, insulated flexile wire will ordinarily be used, with only a portion of the flexile wire incident to the electrode stripped of insulation. However, bare uninsulated flexile wire could alternatively be used throughout, so long as those portions of the uninsulated flexile wire that are exposed on the contact-facing surface of the backing are insulated and shielded from electrical contact (step94), such as by applying a layer of plastic, rubber-like polymers, or varnish, or by an additional layer of gauze or adhesive (or non-adhesive) gel over the exposed wire. The uninsulated flexile wire exposed on other surfaces of the backing could also be insulated or simply be left bare.
• One end of the flexile wire may be terminated as an electrode signal pickup (step95). If insulated flexile wire is used, a portion of the end of the flexile wire is stripped of insulation (step96) using, for instance, a wire stripper or plasma jet. The electrode signal pickup could either be formed by interlacing (or sewing) the flexile wire (step97) into the backing in the shape of the desired electrode (step98) or positioned over the contact-facing area of the backing designated to serve as an electrode signal pickup and embedded within an electrically conductive adhesive (step99). In a yet further embodiment, the flexile wire could be terminated as a connection to a discrete electrode, such as by sewing an uninsulated portion of the end of the electrode wire into the discrete electrode to thereby establish an electrical contact and affix the discrete electrode to the backing. The Universal ECG EKG electrode, manufactured by Bio Protech Inc., Tustin, Calif., is one example of a discrete electrode.
• Finally, the other end of the flexile wire may be terminated as a connection to a circuit board (step100). The flexile wire can be interlaced or sewn onto the circuit board, for instance, by back stitching the flexile wire back and forth across the edge of the circuit board to thereby establish an electrical contact and affix the discrete electrode to the backing.
• In a further embodiment, flexile wire can be used to replace all or part of a printed circuit board, such as battery printedcircuit board62 used in constructing a stress-pliant physiological electrode assembly, as described supra, or for any other application that requires interconnection of electrical or electro mechanical components on a physical substrate or backing. Flexile wire in place of conductive circuit traces can work especially well with simple circuit board layouts, where ample space between components and relatively uncomplicated layouts are amenable to stitched-in interconnections. In addition, the use of flexile wire can simplify circuit layout design in multilayer circuits, as insulated flexile wires can be run across each other in situations that would otherwise require the use of a multilayer printed circuit board or similar solution.
• Through such use of flexile wire, a printed circuit board can be omitted in whole or in part. Interconnects between and connections to the electronic and electro mechanical components formerly placed on the printed circuit board can instead be sewn from flexile wire. For instance, the battery printedcircuit board62 can be replaced by flexile wire interconnects that connect the electrodes to a sewn set of electrical pads formed by over-stitching the flexile wire into electrical contact surfaces of sufficient size to interface with amonitor recorder14 when fitted into thenon-conductive receptacle25. Likewise, thespring65 andclasp66 can be sewn in place using flexile wire to hold a battery in place with flexile wire interconnects connecting the battery to a sewn set of electrical pads formed by over-stitching the flexile wire into electrical contact surfaces of sufficient size to interface with amonitor recorder14 when fitted into thenon-conductive receptacle25. Still other approaches to replacing printed circuit boards with flexile wire interconnects are possible.
• The resultant stress-pliant physiological electrode assembly may be electrically coupled to a broad range of physiological monitors not limited to electrocardiographic measurement. The foregoing method of constructing a stress-pliant electrode assembly is adaptable to manufacturing other forms of dermal electrodes, including electrodes for electrocardiography, electroencephalography, and skin conductance measurements. Further, by adjusting the number of electrodes, the distances among the electrode signal pickups, and the thickness of the flexile wire, the method can be adapted to manufacturing at low cost an electrode assembly that is lightweight and resistant to tensile, compressional and torsional forces, thus contributing to long-term wear and versatility.
• The extended wear electrocardiography monitor, described supra with reference toFIGS. 1-16, is generally worn as a patch adhered to the skin during use. Some patients, however, may not be able to wear an adhesive patch due to allergic reaction, skin condition, or other factors that make the wearing of an adhesive patch, even for a short duration, either undesirable or impracticable. Moreover, athletes, particularly when interested in monitoring performance during training and sports activities, may find the wearing of an adhesive patch a hindrance to movement and at odds with performance monitoring.
• As an alternative to an adhesively-attached electrode patch, the electrodes of the extended wear electrocardiography monitor can be integrated into a wearable garment that can be coupled with a monitor recorder14 (shown inFIG. 1) or similar recordation device.FIG. 17 is a front view of a wearable electrocardiography andphysiology monitoring ensemble300 in accordance with a further embodiment. Thewearable monitoring ensemble300 is provided through awearable garment301, such as a shirt, blouse, or tunic, that is worn about the upper region of the torso that is equipped with anelectrode assembly313. Thewearable garment301 is constructed, at least in part, using a compressible and elastomeric material, such as Spandex, formerly manufactured by E.I. du Pont de Nemours and Company (“DuPont”), Wilmington, Del.; Lycra, manufactured by Koch Industries, Inc., Wichita, Kans.; or elastane. Other types or combinations of compressible and elastomeric materials are possible.
• An electrode patch achieves fully continuous electrode contact through an adhesive or a fixing agent that adheres a gauze or similarly-woven or flexible material against the skin; the gauze serves as a backing to each electrode, which is held captive and firmly in place between the skin and the gauze. In addition, the electrodes themselves could be coated with an adhesive to self-adhere the electrodes directly to the skin. In both forms, the presence of adhesive on the skin's surface can be at variance with extended long-term wear, especially on patients with sensitive or fragile skin or who have allergies or sensitivities to the chemicals or materials used in adhesive patches.
• The construction of thewearable garment301 employs aninternal structure302 that obviates the need to use adhesives or other fixing agents to hold electrophysiology and physiology sensing electrodes into place. Theinternal structure302 allows thewearable garment301 to exert a compressive force against anelectrode assembly313 that is sufficient to keep theelectrodes309 and310 in usably-continuous contact with the wearer's skin throughout the monitoring period. Theelectrode assembly313 contains at least twoelectrodes309 and310 that are both affixed to a backing, either individually or combined. Theelectrode assembly313 is provided on an inside-facing surface of thewearable garment301 on an underside of theinternal structure302 to keep theelectrode assembly313 firmly against the wearer's skin. In contrast to an electrode-equipped adhesive patch, thewearable garment301 permits unconstrained free movement during monitoring and the wearer is typically unaware of the presence of theelectrode assembly313. However, to effectively measure electrophysiology, theelectrodes309 and310 need to be kept in fairly continuous, albeit not absolutely constant, physical contact with the skin.
• Thewearable monitoring ensemble300 obviates the necessity of adhesives or other fixing agents that adhere directly to the skin by utilizing theinternal structure302 of thewearable garment301 to place and retain theelectrode assembly313 securely against the skin. To some degree,internal structure302 inherent in the overall design of thewearable garment301, when in the form of clothing worn about the torso, specifically, a shirt, blouse, or tunic, will retain the relative positions of the various panels that make up thewearable garment301 in place during wear. Elements of the inherent garment design include, for instance, the openings for thearms303aand303b, theneck304, andtorso305 proper. Other elements of inherent garment design are possible.
• To facilitate monitoring purposes, though, the relative position of the panel upon which thesensory assembly313 is affixed to theinternal structure302 on the inside surface of thewearable garment301 must be kept from dramatically shifting about; the location of theelectrode assembly313 ought to be sufficiently stable, so as to avoid displacing theunderlying electrodes309 and310 to the degree that cardiac electric potential signals are degraded or change character.
• The inherent design of thewearable garment301 only provides a partial solution and these structures alone will not suffice to maintain theelectrode assembly313 in fairly continuous physical contact with the skin. Theinternal structure302 of thewearable garment301 is biased to press snuggly against the skin in at least those portions of thewearable garment301 where theelectrode assembly313 need be held in a relatively stable orientation. The compressive bias is provided by the compressible and elastomeric material and theinternal structure302, which can includeelastic bands306a,306b,306c, and306d, embedded longitudinally across the chest, or by a combination of fabric components with varying characteristics of elasticity.
• The compressive force imparted by thewearable garment301 on theelectrode assembly313 is provided by placing theelectrode assembly313 on an inside surface of thewearable garment301 on an underside of theinternal structure302, such that theelectrode assembly313 is firmly “pinned” in place against the skin, yet not adhered. The amount of side-to-side shift or momentary loss of contact that can be tolerated without signal degradation or compromise depends upon the monitoring location. For instance, to optimize capture of P-wave signals, theelectrode assembly313 can advantageously be positioned axially along the midline of a wearer's sternum, such as described in commonly-assigned U.S. Pat. No. 9,700,227, the disclosure of which is incorporated by reference. To secure theelectrode assembly313 in the desired orientation axially along the sternal midline, thewearable garment301 integrates a bias that imparts compressive force circumferentially about the wearer's torso; the compressive force is sufficient to keep the twoelectrodes309 and310 against the skin for the majority of the time during wear and monitoring. However, whereas an electrode patch seeks to keep the electrodes in continuous and stationary contact with the skin at all times, the electrodes here are permitted to actively “float” over the skin's surface, so long at least a part of an electrode's surface contacts the skin. Thus, to a limited extent, theelectrodes309 and310 can slide around the general region on the skin where a cardiac electric potential signal sensing is desired. In addition, the occasional loss of signal pick up that can occur if theelectrode assembly313 briefly loses contact with the skin, such as happens if the wearer makes a sudden movement, can be weathered; cardiac electric potential signals lost through a momentary loss of skin contact are not likely to adversely degrade overall signal fidelity, so long as the loss of contact is sufficiently brief and spans say, no more than a few heartbeats. As a result, thewearable garment301 needs to keep theelectrode assembly313 oriented on the skin in the same overall spot, but theelectrode assembly313 need not be fixed as an absolutely stationary location and some degree of sliding movement or “float” along the skin's surface is permissible.
• Theelectrode assembly313 is also provided with twoelectrical connections311 and312 through which a monitor recorder can receive and record electrical potential signals. One end of each of theelectrical connections311 and312 is connected to one of theelectrodes309 and310, while the other end of each of theelectrical connections311 and312 is terminated to suit interfacing with a compatible form of monitor recorder. In one embodiment, theelectrical connections311 and312 can be connected to the pair ofelectrical pads34 provided on the non-conductive receptacle25 (shown inFIG. 4) to electrically couple theelectrodes309 and310 to areusable monitor recorder14. In a further embodiment, the electrical connections can be adapted to wirelessly interface to a wireless-capable monitor recorder. Each of theelectrical connections311 and312 are interfaced to a wireless transceiver over which the cardiac electric potential signals sensed by theelectrodes309 and310 are transmitted. Other forms of terminating theelectrical connections311 and312 to interface to a monitor recorder are possible.
• Theelectrode assembly313 can be packaged in at least three different forms, including a flexible circuit electrode assembly and flexile wire electrode assemblies with discrete or sewn-in electrodes. These forms of sensor assemblies will now be discussed. First,FIG. 18 is a contact-surface view of a flexiblecircuit electrode assembly313 of thewearable monitoring ensemble300 ofFIG. 17. Theelectrode assembly313 contains twoelectrodes309 and310, which are formed on twoflexible circuits314 and315, respectively. In a further embodiment, the twoelectrodes309 and310 can be formed on a single flexible circuit. The flexile circuits include circuit traces311 and312 that terminate respectively withelectrical pads316 and317 for mating with, for instance, the pair ofelectrical pads34 provided on thenon-conductive receptacle25.
• Second, the twoflexible circuits314 and315 can be replaced with a pair of flexile wires that are sewn or stitched into a pair of discrete electrodes, such as described supra with reference toFIGS. 9 through 15A-C.FIG. 19 is a contact-surface view of a flexile wire interconnect320 of thewearable monitoring ensemble300 ofFIG. 17. The twoelectrodes309 and310 are stitched or sewn323 and324 into the compressible and elastomeric material (not shown) using a pair offlexile wires321 and322. The insulation is first stripped from the ends of the pair offlexile wires321 and322 and an electrical connection is established between the twoelectrodes309 and310 and the pair offlexile wires321 and322. In similar fashion, the pair offlexile wires321 and322 can be electrically connected on their opposite ends toadditional components325 and326, such as thenon-conductive receptacle25, electrical terminals, or a wireless transceiver, by stripping insulation from and sewing orstitching327 and328 the other ends of theflexile wires321 and322 into theadditional components325 and326. Other ways of interconnecting electrodes and additional components using flexile wire, including soldering and crimping, are possible.
• Finally, both the twoflexible circuits314 and315 and the twoelectrodes309 and310 can be respectively replaced with a pair of flexile wires and a pair of sewn-in electrodes.FIG. 20 is a contact-surface view of a flexile wire electrode and interconnect330 of thewearable monitoring ensemble300 ofFIG. 17. A pair ofelectrodes323 and324 are stitched or sewn into the compressible and elastomeric material (not shown) using a pair offlexile wires321 and322. The pair offlexile wires321 and322 can be electrically connected on their opposite ends toadditional components325 and326, such as thenon-conductive receptacle25, electrical terminals or a wireless transceiver, by stripping insulation from and sewing orstitching327 and328 the other ends of theflexile wires321 and322 into theadditional components325 and326. Other ways of interconnecting electrodes and additional components using flexile wire, including soldering and crimping, are possible.
• Thewearable monitoring ensemble300 is advantageous for both patients and athletes because the ambulatory apparatus can collect high-quality ECG and physiological data while the wearer engages in activities of daily living. ECG data are crucial for diagnosing many cardiovascular conditions, but additional data are often necessary for differential diagnoses, such as in diabetic and hypertensive patients. Cardiovascular patients must take particular care in monitoring their status to avoid related adverse events; for example, monitoring temperature can be helpful in cardiovascular patients because cardiovascular system compromises patients' capacity for maintaining a normal body temperature, and cardiovascular patients may be more susceptible to hypothermia in cool environments.
• Athletes also benefit from ECG data combined with additional physiological data to prevent adverse cardiac events, including power sports athletes, aged athletes, and young athletes with congenital heart conditions. Moreover, ECG data combined with other physiological data may aid athletes in optimizing performance. In many instances, blood sugar measurements may aid in generating a diagnosis, prognosis, and treatment plan as well as predicting athletic performance. For example, patients with diabetes or blood sugar levels that are greater than normal are also more likely to develop certain heart diseases, such as ischemic heart disease and myocardial infarction. Moreover, multiple types of physiological data may be combined to predict additional disease conditions, such as the combination of high blood pressure, coronary heart disease, and diabetes, which can severely damage cardiac muscle and lead to heart failure. In addition, blood sugar plays a strong role in athletic performance and recovery; thus, athletes benefit from both monitoring their blood sugar before, during, and after exercise as well as using the monitoring data to elucidate undiagnosed blood sugar conditions. For example, exercise-induced hypoglycemia can severely hamper performance and may indicate a more serious condition that can lead to sudden death.
• Monitoring blood pressure may also be key to elucidating a patient's or athlete's underlying physical condition. Hypertension is the greatest risk factor for cardiovascular disease in both normal and athlete populations. Dubbed the “silent killer,” hypertension is both common as well as under-diagnosed and can damage various organs, leading to a higher risk of left ventricular hypertrophy and sudden death, among other conditions. Further, combined with ECG data, it may provide critical data for determining a patient's cardiovascular condition. For example, as noted above, heart failure is more likely in patients with high blood pressure combined with heart disease and blood sugar dysregulation. Further, silent ischemia is often diagnosed through detecting hypertension and ST depression, which is best observed using an ambulatory ECG device; a combined prolonged QT interval and hypertension are associated with increased risk of pathological cardiovascular conditions, including the risk of sudden death; and hypertensive patients with abnormal T wave patterns exhibit increased left ventricular mass, which enhances the risk of adverse cardiac events, including sudden death. Moreover, while the athletic population maintains a lower blood pressure generally, hypertension remains the greatest cardiac risk factor for athletes. Further, athletes benefit from blood pressure monitoring, particularly during exercise, because untreated hypertension can significantly impair athletic performance; moreover, older athletes are at particular risk for undiagnosed hypertension.
• Further, detecting abnormal respiratory function may facilitate diagnosis, prognosis, and treatment of certain disorders in both patients and athletes. For example, Cheyne-Stokes breathing associated with chronic heart failure is a predictor of poor prognoses associated with cardiac death. In addition, cardiorespiratory conditions are common in athletes but are often undiagnosed. Such conditions not only impair performance, but overtraining with a cardiorespiratory may lead to severe consequences, such as sudden death due to severe bronchoconstriction. Further, sleep decreases the diagnostic efficacy of ECG monitoring alone due to natural heart rate decrease during sleep. As a patient enters non-rapid eye movement (NREM) sleep, the patient undergoes physiological changes due to less sympathetic nervous system activity. Thus, even healthy people may experience sinus bradyarrhythmia during sleep, and ECG monitoring alone may reveal whether the bradyarrhythmia is natural or due to a pathological condition, such as an apnea. Further, if a patient experiences other types of arrhythmias during sleep, a physician may not be able to determine whether an arrhythmia is due to sleep apnea or other morbidity without measuring the patient's air flow, which is the flow of air in and out of the patient's lungs during breathing, or other respiration indicator. However, considering that cardiac manifestations of sleep apnea are most apparent at night, short-term ECG monitoring during business hours may not reveal cardiac arrhythmia.
• While the invention has been particularly shown and described as referenced to the embodiments thereof, those skilled in the art will understand that the foregoing and other changes in form and detail may be made therein without departing from the spirit and scope.

Claims (20)

What is claimed is:

1. A wearable electrocardiography monitoring ensemble, comprising:

at least one internal structure formed within a garment and defined by two horizontal bands across a front surface of the garment;

an electrode assembly positioned within the internal structure, comprising:

at least one electrode to sense cardiac electric signals; and

at least one electrical connection connected on one end to one of the electrodes and interfaced on an other end to a monitor recorder that records the cardiac electric signals,

wherein the internal structure exerts against a top surface of the electrode assembly a compressive force that presses the electrode assembly against a wearer's skin.

2. A wearable electrocardiography monitoring ensemble according toclaim 1, further comprising:

a backing on which the electrodes are affixed.

3. A wearable electrocardiography monitoring ensemble according toclaim 1, further comprising:

a backing on which one of the electrodes is affixed; and

a further backing on which another one of the electrodes is affixed.

4. A wearable electrocardiography monitoring ensemble according toclaim 3, wherein the backing and the further backing are positioned within different internal structures.

5. A wearable electrocardiography monitoring ensemble according toclaim 1, wherein each electrical connection comprises one of a flexible circuit and a flexile wire.

6. A wearable electrocardiography monitoring ensemble according toclaim 5, wherein insulation on one end of the flexile wire is stripped to establish an electrical connection between the corresponding electrode and the flexile wire.

7. A wearable electrocardiography monitoring ensemble according toclaim 1, further comprising:

electrical pads each connected to one of the electrical contacts on an end of the electrical contact opposite the electrode; and

the same or different electrical pads connected to the monitor recorder.

8. A wearable electrocardiography monitoring ensemble according toclaim 1, wherein the electrodes are each formed via flexile wires.

9. A wearable electrocardiography monitoring ensemble according toclaim 1, wherein the electrical connection interfaces wirelessly with the monitor recorder.

10. A wearable electrocardiography monitoring ensemble according toclaim 1, further comprising:

a physiological monitor to monitor one or more physiological conditions of the wearer simultaneously with the sensing of the cardiac electric signals.

11. A method for constructing a wearable electrocardiography monitoring ensemble, comprising:

defining at least one internal structure in a wearable garment via two horizontal bands;

generating an electrode assembly configured for positioning within the internal structure, comprising:

obtaining at least one electrode to sense cardiac electric signals;

connecting at least one electrical connection on one end to one of the electrodes; and

interfacing the electrical connection on an other end to a monitor recorder that records the cardiac electric signals,

wherein the internal structure exerts against a top surface of the electrode assembly a compressive force that presses the electrode assembly against a wearer's skin.

12. A method according toclaim 11, further comprising:

affixing the electrodes on a backing.

13. A method according toclaim 11, further comprising:

affixing each of the electrodes on a separate backing.

14. A method according toclaim 13, wherein the each of the separate backings are positioned within different internal structures.

15. A method according toclaim 11, wherein each electrical connection comprises one of a flexible circuit and a flexile wire.

16. A method according toclaim 15, further comprising:

stripping one end of the flexile wire to establish an electrical connection between the flexile wire and the corresponding electrode.

17. A method according toclaim 11, further comprising:

connecting electrical pads to one of the electrical contacts on an end of the electrical contact opposite the electrode; and

connecting the same or different electrical pads to the monitor recorder.

18. A method according toclaim 11, wherein the electrodes are each formed via flexile wires.

19. A method according toclaim 11, wherein each electrical connection interfaces wirelessly with the monitor recorder.

20. A method according toclaim 11, further comprising:

monitoring a physiological monitor for one or more physiological conditions of the wearer simultaneously with the sensing of the cardiac electric signals.

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