Measurement probe for ECG epicardial monitoring and measurement system for ECG epicardial monitoring with such a probe

Abstract

The present invention relates to a measurement probe for epicardial ECG monitoring, comprising a measuring element (2) for measuring electrical signals from the heart and a connecting element (3) configured to output the measured cardiac signals, the measuring element (2) being electrically connected to the connecting element (3). The measuring element (2) and the connecting element (3) are stacked elements. The present invention also relates to a measurement system for epicardial ECG monitoring, comprising a probe (1) connected to a display device by a signal cable (5).

Description

[Technical Field]

[0001] The present invention relates to a measurement probe for epicardial ECG monitoring that acquires signals directly from the beating heart surface in order to monitor and evaluate the condition of the heart during a procedure, in particular during coronary artery bypass graft surgery performed by a procedure on a beating heart, including an off-pump procedure, and to a measurement probe for epicardial ECG monitoring that enables accurate and continuous signal acquisition during a procedure involving changes in the position of the living heart, and to a measurement system for epicardial ECG monitoring that includes such a probe. [Background technology]

[0002] Devices are known in the art that can acquire ECG signals from a patient during surgery by placing electrodes on the patient's skin and also directly on the heart.

[0003] Polish Patent No. 213307 B1 describes a system and device for cardiac monitoring during cardiac surgery, in which electrodes are placed directly on the patient's cardiac surface. The device is used to assess the state of the myocardium at a surgical site stabilized by a cardiac stabilizer and, optionally, a cardiac positioner. The system comprises a cardiac stabilizer with a chamber and a suction channel connected to a suction pump and measurement electrodes, which are connected via a measurement interface to a measurement block having an immittance measurement module connected to a control and data acquisition system.

[0004] The device described in patent document P.R. 213307 (B1) is an electrode system attached to the working surface of a suction cup on a cardiac stabilizer arm, i.e., the device is attached to the cardiac surface by negative pressure. Negative pressure acting on the cardiac surface can cause local extravasation. The device measures immittance (tissue impedance). Tissue impedance is not a parameter analyzed by cardio monitors as a myocardial ischemia parameter.

[0005] The document US Patent Application Publication No. 2014206973(A1) describes a system and device for remotely monitoring physiological parameters of the cardiovascular system and a method for placing a sensor on the cardiac surface, which requires tissue "clamping" (puncturing) and / or vacuum-induced adhesion. The described device is for continuous, permanent (long-term) monitoring of signals from the cardiac surface, but is not capable of displaying ECG signals in real time on a standard cardio monitor, especially during open-chest surgery. The described device is configured to wirelessly transmit ECG signals to another device that records the acquired signals for later storage and analysis. The target population for utilizing such a device is patients with myocardial failure and arrhythmia. The use of the device in cardiac surgery is not described.

[0006] The device described in patent document U.S. Patent Application Publication No. 2014206973(A1) is not configured to record signals involving non-anatomical positions of the heart in an open-chest environment. In a closed-chest environment, it is impossible to rotate the heart, i.e., to change its position, as is done during coronary artery bypass graft surgery. The described device is delivered via a non-surgical percutaneous procedure. The described structure of the device requires connection to a subcutaneously implanted signal recording (storage) device. The described device is configured to wirelessly transmit ECG signals to another device, which records the acquired signals and analyzes them after storage. Due to the need for wireless signal transmission, the described device does not function in a surgical setting (in an operating room). Removal of the described device from the cardiac surface may cause bleeding (e.g., from epicardial veins) due to premature intervention in the epicardial tissue. Furthermore, the specification mentions the need to provide a physical fixation means, such as negative pressure, to the electrodes to hold them on the cardiac surface. Negative pressure applied onto the cardiac surface can adversely affect the structure of epicardial tissue by causing localized extravasation (hematoma) in the cardiac tissue or pericardium. The described device cannot be repositioned on the cardiac surface without interrupting tissue continuity, because each repositioning of the device directly risks bleeding and increases tissue damage, as tissue puncture or hematoma manifestation due to negative pressure can occur. Furthermore, repositioning the described device requires the handling of a physical fixation means (negative pressure) and a delivery system. Each operation requires time and additional procedures.

[0007] Furthermore, operating the system described in U.S. Patent Application Publication No. 2014206973(A1) may require inserting electrodes into the heart via blood vessels, and moving the heart with electrodes inserted inside the heart is not recommended because such electrodes placed within the heart cavity may puncture or damage the heart wall. The signal acquisition method presented in the described device is performed within the tissue, not on the tissue surface. Therefore, it is an intramural measurement rather than an epicardial measurement. The described device monitors only the anterior wall of the heart. The device cannot be attached to the posterior wall of the heart because the weight of the heart alone would amplify tissue damage caused by the needles, potentially resulting in injury or causing the negative pressure fixation system to malfunction.

[0008] The solutions known from the prior art do not allow flexibility in the placement of the elements for acquiring signals. While the solution of Polish Patent No. 213307 B1 provides a system in which the electrodes are placed on a stable cardiac surface in a fixed position, eliminating the possibility of the electrodes coming into contact with the heart while changing its position, the device of document US2014206973 A1 is an invasive device designed to be retained by the patient for a long period of time, and furthermore the system and device disclosed in document US2014206973 A1 are not attached directly to the patient's heart.

[0009] Furthermore, none of the solutions known in the art provide a device that has dimensions that, when placed on the cardiac surface, provide easy access to the organ without covering a major portion of the organ area.

[0010] ECG monitoring is necessary in many cases, one of which is coronary artery bypass graft surgery. Such surgeries are routinely performed on patients with severe coronary artery atherosclerosis, and the number of such surgeries is steadily increasing, especially due to the aging of society. Until recently, the traditional procedure for performing such surgeries entailed temporarily replacing the cardiopulmonary function with an extracorporeal circulation machine. However, considering several postoperative complications, a procedure based on performing arterial bypass grafting on a beating heart without extracorporeal circulation (off-pump coronary artery bypass grafting - OPCAB) has become popular. While this procedure reduces the mortality and morbidity compared with traditional procedures for some groups of patients, it requires a temporary change in the position of the beating heart, known as cardiac excursion, to expose specific cardiac walls and coronary arteries. During cardiac excursion, highly accurate electrocardiographic monitoring is required to quickly diagnose any cardiac arrhythmias and their blood supply and to take appropriate preventive measures. Standard monitoring of patients undergoing surgery involves electrocardiography (ECG).

[0011] Although exemplary standard techniques for cardiac ECG monitoring have been described above, these techniques are not suitable for procedures utilizing the OPCAB technique. No solution exists for sequential, real-time examination of electrocardiogram recordings from above each bypassed coronary artery territory during the entire bypass sequence, and ECG signals are output from the surgical area to a standard cardio monitor located in the operating room.

[0012] All of the above prior art solutions, and all prior art solutions currently in clinical use, do not guarantee accurate and continuous diagnostic ECG monitoring during coronary artery bypass graft procedures performed on a beating heart with changes in the in vivo position of the heart. The possibility of correctly recording an ECG via electrodes placed on the patient's skin during such procedures can be lost for the following reasons: -Loss of contact with the surrounding tissues of the heart due to changes in the position of the body, -A material is introduced into the patient's chest that isolates the heart from surrounding tissue.

[0013] Loss of sufficient signal to monitor cardiac status precludes accurate monitoring of potential cardiac ischemia and prevents treatment that could mitigate the patient's life-threatening condition.

[0014] Currently, there is no available solution (device) that can measure ECG directly from the cardiac surface. Cardiac surgery uses electrodes that are temporarily inserted into the cardiac tissue (wall), which act to stimulate the heart rather than record ECG signals. Such electrodes penetrate the cardiac tissue. Optionally, the use of electrodes for ECG signal reading may result in repeated punctures of the cardiac tissue, which may induce bleeding. Furthermore, needle-tipped electrodes may disintegrate when removed from the cardiac tissue, which may increase bleeding. Secondly, using electrodes that penetrate the cardiac tissue and then cutting the needle after placement directly leads to the risk of further bleeding and also requires the use of multiple electrodes—i.e., a new electrode is needed for each change of location. Therefore, this variant would also result in repeated punctures of the cardiac tissue, which may pose a risk of bleeding. Summary of the Invention [Problem to be solved by the invention]

[0015] The present invention allows for the acquisition of ECG signals from the cardiac surface, a non-invasive procedure that is safe for the heart, even if the heart needs to be repositioned multiple times during surgery without covering large areas of the heart. [Means for solving the problem]

[0016] A measurement probe for epicardial ECG monitoring comprises a measuring element for measuring electrical signals from the heart and a connecting element configured to output the measured cardiac signals through a connecting piece, the measuring element being electrically connected to the connecting element. The measuring element is a laminated element having a signal collection layer distributed over at least a portion of the measuring element and a base layer extending over the entire surface of the measuring element. The connecting element is a laminated element having a conductive layer, a dielectric layer insulating the conductive layer, and a base layer extending over the entire surface of the connecting element. The connecting piece provided at the end of the connecting element opposite the measuring element is also a laminated element having a conductive layer and a base layer. The maximum dimension of the measuring element perpendicular to the thickness direction is 30 mm.

[0017] Preferably, the measuring element between the signal collection layer and the base layer comprises a conductive layer, while in the connecting element, the conductive layer is disposed on the dielectric layer and the base layer is positioned on the conductive layer, and the conductive layer of the measuring element and the conductive layer of the connecting element form a continuous conductive layer extending across the measuring element and the connecting element.

[0018] Preferably, in the measuring element, the base layer is located on the signal collecting layer, and in the connecting element, the base layer is located on the conductive layer, which is disposed on the dielectric layer.

[0019] Preferably, in the measuring element, the base layer is located on the signal collection layer, and in the connecting element, the base layer is located on the conductive layer, and the conductive layer is disposed on the dielectric layer, and the signal collection layer of the measuring element and the conductive layer of the connecting element form a continuous layer extending across the measuring element and the connecting element.

[0020] Preferably, in the measuring element, a base layer is located on top of the signal collecting layer, while in the connecting element, a conductive layer is arranged on top of the dielectric layer and the base layer is located on top of the conductive layer, and the conductive layer of the connecting element in the part adjacent to the measuring element is made of the same material as the signal collecting layer of the measuring element, while the remaining part is made of a different conductive material.

[0021] Preferably, the signal collection layer of the measuring element is also an adhesive layer to which the probes can be fixed.

[0022] Preferably, the signal collection layer of the measuring element partially overlaps the dielectric layer of the connecting element.

[0023] Preferably, in the measuring device, the signal collection layer is located on the adhesive layer.

[0024] Preferably, the measuring element comprises an adhesive layer located on the periphery of the measuring element and partially covering the signal collection layer.

[0025] Preferably, in the measuring element, the adhesive layer is a graphene-TPU layer.

[0026] Preferably, the conductive layer in the connection element is a graphene-PMMA layer.

[0027] Preferably, the signal collection layer in the measuring element is a graphene layer.

[0028] Preferably, the conductive layer in the connection element is a graphene layer.

[0029] Preferably, the conductive layer is at least partially a silver layer.

[0030] Preferably, the measuring element in a plane perpendicular to the thickness direction has a circular shape.

[0031] Preferably, the connection elements in a plane perpendicular to the thickness direction have a rectangular shape.

[0032] Preferably, the measuring element and the connecting element are located in the same plane.

[0033] Preferably, all layers are made of flexible materials.

[0034] Preferably, the dielectric layer and the base layer are made of the same material.

[0035] Preferably, the adhesive layer has an annular shape.

[0036] Preferably, the connection element is connected to the signal cable through a connection piece.

[0037] Preferably, the signal collection layer comprises at least one carrier, a conductive material, and optionally at least one adhesion promoter.

[0038] Preferably, the adhesion promoter comprises one substance selected from lanolin, agar, sodium alginate, collagen, gelatin, starch and cellulose, and derivatives thereof such as carboxymethylcellulose, carboxymethylstarch, hydroxypropylstarch, or mixtures thereof.

[0039] Preferably, the conductive material is at least one selected from Au, Ag, PdAg, graphite, graphene, RuO2, IrO2, Bi2Ru2O7, ITO, or a mixture thereof.

[0040] Preferably, the carrier is a polymer compound containing a solvent or a resin containing a solvent.

[0041] Preferably, the polymer is one selected from ethyl cellulose, polypropylene, polyethylene, polyester and polystyrene, poly(methyl methacrylate) (PMMA), thermoplastic polyurethane elastomer (TPU), polylactic acid (PLA) or a mixture thereof.

[0042] Preferably, the solvent is one selected from acetone, dimethylformamide (DMF), butyl carbitol acetate (OKB), chloroform, or a mixture thereof.

[0043] Preferably, the graphene-TPU layer comprises graphene, hydroxypropyl starch, and a thermoplastic polyurethane elastomer in dimethylformamide.

[0044] Preferably, the graphene-TPU layer comprises 10% by weight sodium graphene, 10% by weight hydroxypropyl starch, and 80% thermoplastic polyurethane elastomer in dimethylformamide.

[0045] Preferably, the graphene-PMMA layer comprises graphene and poly(methyl methacrylate) in butyl carbitol acetate.

[0046] Preferably, the graphene-PMMA layer comprises 13 wt% graphene and 87 wt% poly(methyl methacrylate) in butyl carbitol acetate.

[0047] Preferably, the graphene layer comprises sodium alginate, graphene, and poly(methyl methacrylate) in butyl carbitol acetate.

[0048] Preferably, the graphene layer comprises 10% by weight sodium alginate, 13% by weight graphene, and 77% by weight poly(methyl methacrylate) in butyl carbitol acetate.

[0049] Preferably, the graphene layer comprises poly(methyl methacrylate) in butyl carbitol acetate, graphene, and / or agar.

[0050] Preferably, the silver layer comprises silver microflakes in a matrix.

[0051] Preferably, the silver layer comprises 70% by weight silver microflakes and 30% by weight poly(methyl methacrylate) in butyl carbitol acetate.

[0052] Preferably, the matrix comprises a solution of poly(methyl methacrylate) in butyl carbitol acetate.

[0053] Preferably, the dielectric layer comprises a dielectric paste.

[0054] Preferably, the adhesive layer comprises a polymer and an adhesion promoter.

[0055] Preferably, the polymer is one selected from ethyl cellulose, polypropylene, polyethylene, polyester and polystyrene, poly(methyl methacrylate) (PMMA), thermoplastic polyurethane elastomer (TPU), polylactic acid (PLA), and mixtures thereof.

[0056] Preferably, the adhesion promoter is one selected from lanolin, agar, sodium alginate, collagen, gelatin, starch and cellulose, and derivatives thereof such as carboxymethylcellulose, carboxymethylstarch, hydroxypropylstarch, or mixtures thereof.

[0057] Preferably, the base layer is one material selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polycarbonate (PC), polyethersulfone (PES), polyarylate (PAR), polycyclic olefin (PCO) or polynorbornene (PNB), polyimide (PI), fluorine polyester or copolymers thereof.

[0058] Preferably, the individual layers of the measuring element and the connecting element are produced by a printing process on a base layer.

[0059] Preferably, the diameter of the measuring element is 10 mm to 30 mm.

[0060] Preferably, the thickness of the dielectric layer, the signal collection layer, and the connection layer is within the range of 10 to 15 μm.

[0061] Preferably, the thickness of the base layer is in the range of 40 to 75 μm.

[0062] Preferably, the thickness of the graphene-containing layer is in the range of 10 to 30 μm.

[0063] 1 is a measurement system for epicardial ECG monitoring equipped with a probe according to the above embodiment;

[0064] Preferably, the system includes a signal cable connecting the probe to a display device.

[0065] Preferably, a connection piece for connection to a signal cable is located at the end of the connecting element of the probe opposite the measuring element of the probe.

[0066] Preferably, the display device comprises a cardio monitor.

[0067] The probe of the present invention allows for the maintenance of diagnostic ECG signal monitoring during surgery, even with a heart in a non-in vivo position or surrounded by a surgical isolator. This allows for optimal positioning of the heart, regardless of its location, without risk of losing signals from any of its walls, allowing for more free movement of the heart in the surgical field. Furthermore, the probe provides continuous information to the surgical team, i.e., by continuously monitoring the patient's cardiac perfusion. Having such information reduces the pressure on the surgical team, allowing for the fastest possible surgery. Several scientific papers have reported that such pressure can affect the quality of the surgery being performed and the optimal number of bypasses created in the coronary arteries. The probe of the present invention also allows for monitoring of cardiac walls that are not undergoing revascularization. The probe can also be repositioned at any time on a different location on the heart, which is useful, for example, in the event of a malfunction during the insertion of a coronary shunt, when the previous position of the probe does not indicate ischemia in the bypassed area of the heart. At such times, the probe can be quickly re-applied to another location on the heart (e.g., the opposite wall), resulting in fast and accurate intraoperative diagnosis. Such a situation may occur when the position of the heart prepared for a given arterial bypass graft procedure predicts poor blood flow in the coronary arteries on the opposite (other) side of the heart.

[0068] All the above advantages allow the initiation of treatment to predict the outcome of cardiac ischemia during coronary artery bypass graft surgery, reducing the risk of circulatory arrest at critical stages of surgery and the need to initiate resuscitation and switch to extracorporeal circulation for life-saving procedures, thereby significantly reducing the risk of postoperative complications such as death, heart failure, myocardial infarction, and multiple organ failure due to low cardiac output syndrome.

[0069] The probe according to the invention also has applications in procedures other than coronary artery bypass surgery, such as monitoring the electrical activity of a heart exposed to cardioplegia solutions (intracardiac surgery for heart valves and congenital diseases), intraoperative diagnosis of acute heart failure during any type of surgical procedure in patients using non-diagnostic ECG recording from the body surface, or cardiac surgery using cardiac surgical robots. In the latter type of surgery, access to the heart is only provided by a so-called thoracoscopic port, with an incision diameter of approximately 1 cm. Due to the properties described below, the probe according to the invention is flexible and can be gripped without losing its properties, which allows the probe to be placed even through a small thoracoscopic port.

[0070] Furthermore, it should be understood that the above uses of the probe are exemplary and that the probe according to the present invention can be used, inter alia, for intraoperative diagnosis of zones of myocardial necrosis by detecting specific characteristics of the electrical signals generated by areas of the heart where necrosis has developed (zones of previous cardiac infarction).

[0071] Furthermore, due to its size, flexibility, and freedom of placement, the probe can be used as an epicardial electrode for electrically stimulating the heart, for studying electrical signals from the pulmonary vein surface inside the pericardium, and for electrical stimulation of the pulmonary veins, or for electrical mapping of the atria, including the left atrial appendage, as well as for many other medical and diagnostic applications not described herein.

[0072] The main functions of the probe according to the present invention include: - Acquiring ECG signals from the surface of the beating and non-beating heart without the need for intracardiac insertion of electrodes, eliminating the risk of puncturing or damaging the heart wall; -Detection of cardiac ischemia; - non-invasive fixation to the cardiac surface based on adhesion is possible without providing additional fixation means, without additional negative pressure, without the need to destroy the integrity of the tissue, and without the need for additional catheters. In other words, in the solution according to the invention, the adhesive mechanism is integrated into the probe and acts automatically in contact with the tissue, without external energy supply for activation, so that fixation to the surface is performed under visual control in an open chest condition, avoiding injury (damage) to structures in the cardiac wall (for example blood vessels); - The configuration for acquiring ECG signals from all walls of the heart and atria allows for free probe placement, since the probe does not come into contact with epicardial tissue; -Can be repeatedly applied to the cardiac surface without increased risk of epicardial tissue damage; -The probe can be connected to any commercially available cardio monitor to display the ECG signal continuously on a standard monitor; The probe can be used in conjunction with any type (model) of cardiac stabilizer approved for human use, and can also be used during procedures in which a cardiac stabilizer is not used.

[0073] A probe according to the present invention will be described below with reference to the drawings. [Brief explanation of the drawings]

[0074] [Figure 1] 1 is an exploded isometric view of a probe according to the present invention; FIG. [Figure 2] 1A and 1B are diagrams illustrating a method for arranging probes according to the present invention. [Figure 3] 1 shows an operating room during an operation using a probe and measurement system according to the present invention, with medical staff and medical equipment prepared in the operating room; [Figure 4]1 is a cross-sectional view of a most preferred embodiment of a probe according to the present invention, in which the conductive layer extends across the measuring element; [Figure 5] FIG. 5 is a cross-sectional view of the probe of FIG. 4 with twice the thickness of the signal collection layer. [Figure 6] 1 is a cross-sectional view of an embodiment of a probe according to the present invention. [Figure 7] FIG. 7 is a cross-sectional view of the probe of FIG. 6 having twice the thickness of the signal collection layer. [Figure 8] 1 is a cross-sectional view of an embodiment of a probe according to the present invention in which the conductive layer and the signal collection layer are made of the same material. [Figure 9] 9 is a cross-sectional view of the probe of FIG. 8 with twice the thickness of the connecting layer and the signal collection layer. [Figure 10] 1 is a cross-sectional view of an embodiment of a probe according to the present invention in which the conductive layer extends over only a portion of the conductive element and the signal collection layer extends over a portion of the connecting element. [Figure 11] FIG. 11 is a cross-sectional view of the probe of FIG. 10 with twice the thickness of the signal collection layer. [Figure 12] FIG. 7 is a cross-sectional view of the probe of FIG. 6 having an annular adhesive layer. [Figure 13] 8 is a cross-sectional view of the probe of FIG. 7 having an annular adhesive layer. [Figure 14] 9 is a cross-sectional view of the probe of FIG. 8 having an annular adhesive layer; [Figure 15] 10 is a cross-sectional view of the probe of FIG. 9 having an annular adhesive layer; [Figure 16] 5 is a cross-sectional view of the probe of FIG. 4 having an annular adhesive layer; [Figure 17] 6 is a cross-sectional view of the probe of FIG. 5 having an annular adhesive layer; [Figure 18] 11 is a cross-sectional view of the probe of FIG. 10 having an annular adhesive layer; [Figure 19] FIG. 12 is a cross-sectional view of the probe of FIG. 11 having an annular adhesive layer. DETAILED DESCRIPTION OF THE INVENTION

[0075] Description of different probe structures The probe 1 according to one embodiment of the present invention shown in FIG. 1 has the form of an elongated, flat laminated element including a measuring element 2. The measuring element 2 has, for example, a circular shape with a diameter of 10 mm to 30 mm, e.g., 15 mm, in a plane perpendicular to the thickness direction. The probe 1 further includes a strip-shaped, e.g., rectangular, connecting element 3. A connecting piece 4 is arranged at the end of the connecting element 3 opposite the measuring element 2 so as to connect to a signal cable 5. The measuring element 2 and the connecting element 3 are electrically connected and located in the same plane. The measuring element 2 is configured to measure electrical signals from the cardiac surface, and the connecting element 3 is configured to output the signals measured from the cardiac surface. The measuring element 2 includes a signal collecting layer 22 distributed over at least a portion of the measuring element 2, and a base layer 21, which is a substrate extending over the entire surface of the measuring element 2 and on which the remaining layers are placed. The substrate functions as an insulator for the signal collecting layer and the connecting layer 32, described below, from the external environment of the patient's body. The connection element 3 comprises a conductive layer 32, a dielectric layer 33 that insulates the conductive layer 32, and a base layer 21 that extends over the entire surface of the connection element 3. The dielectric layer 33 extends over the entire length of the connection element 3 of the probe 1, and completely insulates the conductive layer 32 disposed thereon from the external environment, particularly the cardiac surface, over the entire length of the connection element 3. The connection piece 4 provided at the end of the connection element 3 comprises the base layer 21 and the conductive layer 32 disposed thereon.

[0076] During tests carried out on various models of probes, it was found that in the most preferred embodiment shown in Figures 4 and 5, the probe 1 comprises, in the measuring element 2, a base layer 21 and a signal collection layer 22 which is simultaneously an adhesive layer 23, and in the connecting element 3, the base layer 21 is arranged on a conductive layer 31 which is arranged on a dielectric layer 33, the conductive layer 32 of the connecting element 3 extending across the measuring element 2 so as to be arranged between the base layer 21 and the signal collection layer 22 in this element. In other words, in the measuring element 2, the base layer 21 is arranged on the conductive layer 32, which is arranged on the signal collection layer 22.

[0077] Furthermore, the conductive layer 32 of the measuring element 2 and the conductive layer 32 of the connecting element 3 are made as one component from a single material and comprise a continuous layer extending over the entire length of both elements 2 and 3. Furthermore, the measuring element 2 is entirely covered by a base layer 21, which covers the conductive layer 32, with the remaining part of the signal collection layer 22 being present at the end of the measuring element 2. The most preferred embodiment will be described in detail below in connection with a description of the composition of the individual layers.

[0078] Other possible embodiments of the present invention are described below.

[0079] In the embodiment shown in Figures 6 and 7, the probe 1 comprises, in the measuring element 2, a base layer 21 arranged on a signal collection layer 22, in the connecting element 3, a base layer 21 arranged on a conductive layer 32 arranged on a dielectric layer 33, and in the connecting piece 4, a conductive layer 32 arranged on the base layer 21.

[0080] 8 and 9, in the measuring element 2, the base layer 21 is located on the signal collecting layer 22, and in the connecting element 3, the base layer 21 is located on the conductive layer 32 which is disposed on the dielectric layer 33. Furthermore, the signal collecting layer 22 of the measuring element 2 and the conductive layer 32 of the connecting element 3 are made of the same material and form a continuous layer extending from the measuring element 2 to the connecting element 3. Furthermore, the connecting element 3 in the connecting piece 4 has the conductive layer 32 located on the base layer 21.

[0081] 10 and 11, the probe 1 includes a base layer 21 located on the signal collection layer 22 in the measuring element 2, a base layer 21 located on a conductive layer 32 located on a dielectric layer 33 in the connecting element 3, and a conductive layer 32 located on the base layer 21 in the connecting piece 4. In this embodiment, the conductive layer 32 of the connecting element 3 in the portion adjacent to the measuring element 2 is made of the same material as the signal collection layer 22 of the measuring element 2, and the remaining portion is made of a different conductive material. In other words, part of the connecting layer 32 of the connecting element 3 is a signal collection layer 2 that forms a single layer together with the signal collection layer 22 of the measuring element 2. While FIG. 11 shows an embodiment in which the double-thick signal collection layer 22 is located on the measuring element 2 and part of the connecting element 3, an embodiment in which the double-thick signal collection layer 22 is located only on the measuring element 2 is also possible.

[0082] In each variant of the above embodiments, the signal collection layer 22 of the measuring element 2 partially overlaps the dielectric layer 33 of the connecting element 3 .

[0083] In another variation of each of the above embodiments, the signal collection layer 22 may comprise an adhesive layer 23, as in the most preferred embodiment.

[0084] In a variation of each of the above embodiments, in the measuring element 2, the signal collection layer 22 is located on the adhesive layer 23, and in another embodiment, the adhesive layer 23 is located on the periphery of the measuring element 2 and partially covers the signal collection layer 22.

[0085] In another modification of one embodiment of the present invention, the probe 1 of the above embodiment further includes, in the measuring element 2, a ring-shaped adhesive layer 23 located on the periphery of the measuring element 2, as shown in FIGS.

[0086] In the above embodiment, the base layer 21 of the measuring element 2, the connecting element 3 and the connecting piece 4 preferably consist of one element.

[0087] Probe Composition In describing the composition of the probe according to the present invention, a "derivative" should be understood as any compound prepared by substituting one or more atoms in the molecule with functional groups (by changing the structure) or by substituting groups of other atoms. A "matrix" is a continuous phase in which the functional phase particles are suspended, and the matrix provides the flexibility while the flakes containing the functional phase particles provide the conductivity of the layer, so that the matrix provides corresponding physical parameters different from those of the functional phase particles, e.g., the polymer in which the graphene flakes are suspended. A "carrier" is a matrix in a liquid state before hardening.

[0088] Unless otherwise noted, paste and layer compositions are described herein before evaporation of the solvent. After evaporation, the amount of solvent in the paste is negligible or zero. The weight ratio of solvent to polymer before evaporation is described in the subsection entitled "Exemplary Steps for Probe Fabrication."

[0089] In the above embodiment of the structure of the above probe 1, all layers consist of flexible material.

[0090] In the above embodiment of the structure of the probe 1, the base layer 21 consists for example of a PET film.

[0091] In subsequent embodiments, the dielectric layer 33 and the base layer 21 are made of the same material.

[0092] In the preferred embodiment shown in Figures 4 and 5, the signal collection layer 22, which is simultaneously the adhesive layer 23, is a layer further described herein as a "graphene-TPU" layer, and the conductive layer 32 is a layer further described herein as a "graphene-PMMA" layer. In the most preferred variant, the "graphene-TPU" layer comprises a thermoplastic polyurethane elastomer (TPU), graphene, which acts as a conductive material, and hydroxypropyl starch (Lycoat RS720 starch), a starch derivative that acts as an adhesion promoter and solvent. In this embodiment, the preferred ratio is 80 wt. % thermoplastic polyurethane elastomer TPU, 10 wt. % Lycoat RS720 starch, and 10 wt. % graphene as graphene flakes (in the form of a paste).

[0093] In the embodiments shown in Figures 6, 7, 12, 13, 16, and 17, the signal collection layer 22 in the measurement element 2 is a layer described herein as a "graphene" layer, while in other embodiments shown in Figures 8, 9, 14, and 15, the graphene layer is also the conductive layer 32 in the connection element 3. However, in the embodiments shown in Figures 10, 11, 18, and 19, the signal collection layer 22 in the measurement element 2 and part of the connection layer 32 in the connection element 3 are graphene layers, and in the remaining part, the conductive layer 32 of the connection element distal from the measurement element 2 is, for example, a silver layer. It will be apparent that this solution is not limited to the case where the signal collection layer 22 is a graphene layer and the conductive layer 32 is a silver layer, as will be described later.

[0094] In another variation, the graphene layer comprises sodium alginate, graphene, and poly(methyl methacrylate) in butyl carbitol acetate. The alginate level may be in the range of 10-20 wt. % and, more specifically, in the range of 10-12 wt. In one embodiment, a suitable ratio is 10 wt. % sodium alginate, 13 wt. % graphene, and 77 wt. % poly(methyl methacrylate) in butyl carbitol acetate. In an alternative variation of this embodiment, a suitable ratio is 12 wt. % sodium alginate, 13 wt. % graphene, and 75 wt. % poly(methyl methacrylate) in butyl carbitol acetate.

[0095] In another variation of this embodiment, the graphene layer comprises agar, graphene, and poly(methyl methacrylate) in butyl carbitol acetate.

[0096] In yet another variation, the graphene layer comprises graphene and poly(methyl methacrylate) in butyl carbitol acetate.

[0097] In the above-described embodiments shown in Figures 4-7, 10-13, and 16-19, the conductive layer 32 is at least partially a layer referred to herein as a silver layer, which may consist of silver microflakes, e.g., 25 μm in flake diameter and less than 10 nm in thickness, in a matrix. The matrix is a poly(methyl methacrylate) solution in butyl carbitol acetate. An exemplary silver layer comprises 70% by weight silver microflakes and 30% by weight poly(methyl methacrylate) in butyl carbitol acetate. While the use of silver microflakes in the conductive layer significantly improves the strength of the signal transmitted by the probe, the most preferred embodiment of the present invention, which does not have a silver layer, ensures sufficient conductive properties necessary to achieve the objectives of the present invention.

[0098] In the above embodiment, the thickness of the dielectric layer 33, the signal collection layer 22 and the connection layer 32 is 10-15 μm, and in the above embodiment, the signal collection layer 22 is a graphene layer, a graphene-TPU layer or a graphene-PMMA layer, and its thickness is in the range of 10-30 μm, because the graphene, graphene-TPU and graphene-PMMA layer can be formed as a single layer or a double layer (having twice the thickness).

[0099] The thickness of the base layer 21 in the above embodiment is in the range of 40 to 75 μm.

[0100] In the above embodiment, the signal collection layer 22 includes at least one carrier, a conductive material, and optionally at least one adhesion promoter, where the adhesion promoter is one selected from lanolin, agar, sodium alginate, collagen, gelatin, starch, cellulose, carboxymethyl cellulose, carboxymethyl starch, hydroxypropyl starch (Lycoat RS720 starch), or a mixture thereof. The conductive material is at least one selected from Au, Ag, PdAg, graphite, graphene, RuO2, IrO2, Bi2Ru2O7, ITO, or a mixture thereof. The carrier is a polymer compound with a solvent or a resin with a solvent.

[0101] In the above embodiments in which the carrier of the signal collection layer 22 and / or the connecting layer 32 is a polymeric compound having a solvent, the polymer is one selected from ethyl cellulose, polypropylene, polyethylene, polyester and polystyrene, poly(methyl methacrylate) (PMMA), thermoplastic polyurethane elastomer (TPU), polylactic acid (PLA) or a mixture thereof.

[0102] In some embodiments, the conductive layer 32 is a graphene-PMMA layer containing graphene microflakes, preferably 8-15 nm thick and larger than 2 μm in diameter, in a matrix. The matrix is a poly(methyl methacrylate) solution (PMMA) in butyl carbitol acetate. In a preferred embodiment, the graphene-PMMA layer contains 13% by weight graphene and 87% by weight poly(methyl methacrylate) in butyl carbitol acetate. The use of graphene ensures good electrical conductivity, and the strength of the conductivity can be adjusted by the amount of graphene added. In a preferred embodiment, the diameter of the conductive graphene flakes is larger than the thickness of the layer, so that individual flakes can conduct signals through the layer and overcome the high resistance of the layer, eliminating the need for a high concentration of graphene flakes to achieve the required conductivity.

[0103] In some variations of the probe 1, resistance tests of the connection layer 32 were carried out and the following was found. When the conductive layer 32 (in the measuring element 2 and the connecting element 3) was a silver layer about 1 mm wide (the dimension perpendicular to the thickness direction was small), the resistance value was 30±1Ω. When the conductive layer 32 (in the measuring element 2 and in the connecting element 3) was a wide graphene layer (PMMa polymer + graphene) with a width of about 5 mm, the resistance was 2.4±0.15 Ω. When the conductive layer 32 (in the measuring element 2 and the connecting element 3) was an elongated graphene layer (PMMa polymer + graphene) about 1 mm wide, the resistance was 37±1.9 Ω.

[0104] In the above embodiments, the solvent used in the carrier of the signal collection layer 22 and / or the connecting layer 32 is one selected from acetone, dimethylformamide (DMF), butyl carbitol acetate (OKB), chloroform, or a mixture thereof.

[0105] In the above embodiments, the dielectric layer 33 may be a dielectric paste.

[0106] In the above-described embodiments in which the probe 1 comprises a separate adhesive layer 23, the adhesive layer 23 comprises a polymer and an adhesion promoter, the polymer of the adhesive layer 23 being one selected from ethyl cellulose, polypropylene, polyethylene, polyester and polystyrene, poly(methyl methacrylate) (PMMA), thermoplastic polyurethane elastomer (TPU), polylactic acid (PLA), or a mixture thereof, and the adhesion promoter of the adhesive layer 23 being at least one substance selected from lanolin, agar, sodium alginate, collagen, gelatin, starch and cellulose, and derivatives thereof such as carboxymethyl cellulose, carboxymethyl starch, hydroxypropyl starch, or a mixture thereof.

[0107] As noted above, in a preferred embodiment, adhesive layer 23 is one layer with signal collection layer 22 .

[0108] In one embodiment, the base layer 21 includes one material selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polycarbonate (PC), polyethersulfone (PES), polyarylate (PAR), polycyclic olefin (PCO) or polynorbornene (PNB), polyimide (PI), and fluorine polyester.

[0109] Exemplary steps for probe fabrication The probe 1 of the present invention can be manufactured by a printing process, such as a screen printing technique, on a flexible substrate.

[0110] When printing by this technique, the carrier is a polymer dissolved in a solvent, which is passed through a suitable screen and evaporated after precipitating the carrier onto a substrate such as base layer 21, leaving a hardened paste containing a layer of probe 1.

[0111] In a preferred embodiment, the screen used for printing, to which the ink used for printing is applied, is a polyester screen having a density of 77 to 90T, preferably with a gap between the screen and the substrate of about 700 μm, a squeegee pressure of about 10 to 50 N, a squeegee movement speed of preferably 600 mm / min, and a squeegee rake of 45 degrees.

[0112] During the screen printing process to prepare the pastes that form each layer of probe 1 and to produce layers of sufficient quality, it is important that the paste has a high viscosity to prevent spreading on the screen, allowing for the printing of the precise patterns necessary to produce probes with accurate dimensions, and that it is sensitive to active shear forces, which inevitably decrease the viscosity of the paste. In other words, as the shear rate increases, the viscosity of the paste decreases significantly—this effect is called shear thinning. After the paste passes through the screen, it settles onto the substrate and the shear rate returns to a low value. During this stage of the screen printing process, the viscosity of the paste increases rapidly to prevent spreading of the pattern immediately after printing and to smooth out any irregularities created by mapping the screen onto the newly printed layer during the first milliseconds after printing. It is preferable that the paste exhibit reasonable thixotropy (liquid memory), and that the process of viscosity increase in the paste is not rapid. Pastes used to produce layers by the thick-layer method should have a viscosity of approximately 10 s -1 At a shear rate of 1000 rpm, the viscosity should be characterized by a viscosity of 50 to 70 Pa·s, with a slope of the viscosity curve in the range of approximately -0.50 to -0.65.

[0113] Viscosity measurements were performed on composites formed with the above-mentioned composition of Probe 1 at varying shear rates, and flow curves were determined at a constant temperature of 20 °C. Across the entire shear rate range, low-viscosity pastes containing less than 3 wt% graphene did not exhibit shear-thinning properties. A clear increase in viscosity was observed only in pastes with higher graphene contents; pastes with graphene concentrations above 10 wt% exhibited extremely high viscosities, significantly exceeding the values acceptable for pastes used in screen printing techniques. If the viscosity of the composite is too high, it can hinder paste application and cause discoloration of the printed layer. Therefore, in the most preferred embodiment, the graphene content in the "graphene-TPU" layer is set to 10 wt%, and before solvent evaporation, the carrier consists of 10-15 wt% thermoplastic polyurethane elastomer (TPU) dissolved in dimethylformamide (DMF), which constitutes 85-90% of the carrier. After evaporation, the thermoplastic polyurethane elastomer constitutes 80% of the layer, while the dimethylformamide has completely evaporated.

[0114] In the "graphene-PMMA" layer, more graphene was available by using a larger amount of solvent relative to the polymer. In the most preferred embodiment, the graphene content in the "graphene-PMMA" layer was set to 13 wt %. Before solvent evaporation, the carrier consisted of 8-10 wt % poly(methyl methacrylate) (PMMA) dissolved in butyl carbitol acetate (OKB), which constituted 90-92 wt % of the carrier. After evaporation, the poly(methyl methacrylate) constituted 87% of the layer, while the butyl carbitol acetate was completely evaporated.

[0115] To ensure proper properties of the individual layers, it is necessary to select appropriate curing parameters for the print.

[0116] In the case of the connecting layer 32 and the signal collection layer 22, solvent inks are suitable for printing, and evaporation of the solvent is carried out in a drying unit of a thermal chamber. The optimum curing time and temperature are 120°C for 30 minutes, parameters that prevent degradation of the overprint.

[0117] In the case of the dielectric layer 33, the curing of the overprint is carried out in a UV dryer, since most practical printing inks are photosensitive inks. In the case of the UV dryer, a suitable conveyor belt travel and lamp power were selected. The optimum conveyor belt travel is 50 mm / min, and the lamp power is 100 W.

[0118] Fixing the probe and transmitting signals During surgery, the probe 1 is fixed to the heart by attaching the signal collection layer 22 of the measuring element 2 to the heart surface. Due to the adhesive properties provided by the signal collection layer 22 / adhesive layer 23 composition or a separate adhesive layer 23, and the lightness of the probe 1, the probe can be easily attached to the heart by adhesion, causing no damage to the organ surface, and providing non-invasive measurements.

[0119] Signals collected by the signal collection layer 22 of the measuring element 2 are transmitted to the connection piece 4 through the conductive layer 32 of the connection element 3, and the measuring element 2 of the probe 1 acquires signals from the heart only through the signal collection layer 22, while the measuring element 2 is insulated from the surgical field on the other side by the base layer 21. The connection element 3 is completely insulated from the heart by the base layer 21 on one side and the dielectric layer 33 on the other side. ECG signals collected from the heart surface are transmitted by the connection layer 32 to the connection piece 4 extending from the connection element 3 and configured to connect to a signal cable 5 configured to connect to a cardio monitor that is part of the measurement system 6.

[0120] The probe 1 of the present invention is adapted for use with any cardio monitor used in an operating room through its dedicated signal cable 5. The end of the probe 1 is connected to the signal cable 5, which is secured to an ECG skin electrode through a connector 4 in the standard surgical procedure.

[0121] The connecting piece 4, located at the end of the probe 1 opposite the measuring element 2, forms a platform to which a standard signal cable 5 can be attached using a so-called spring clip, a type of clip well known in the art, without puncturing or damaging the connecting piece 4. The connecting piece 4 has, in a plane perpendicular to the thickness direction, a rectangular shape, for example, with dimensions of the base layer 21 preferably 7 mm x 22 mm and the connecting layer 32 preferably 5 mm x 20 mm, or any shape and dimensions sufficient to attach the connecting piece 4 to such a standard clip and establish a connection between the clip and the conductive layer 32 of the connecting element 3 of the probe 1. As mentioned above, the connecting piece 4 is insulated from only one side by the base layer 21, making it possible to establish an electrical connection between the signal cable 5 and the conductive layer 32 of the connecting element 3.

[0122] Such a connection ensures the possibility of reading and interpreting signals collected directly from the cardiac surface as if they were standard measurement readings from the skin. Thus, the inventive probe 1 transposes ECG monitoring from the skin surface to monitoring from the cardiac surface. The method of connecting the probe to the cardio monitor through the connecting piece 4 ensures flexibility of use, eliminating the need for an additional measurement system 6, i.e., electronic circuitry and software. Furthermore, this method of connecting the inventive probe 1 to the cardio monitor ensures that the ECG curve is displayed on the cardio monitor in a standard manner known to medical staff 7a, 7b, 7c, without the need for a separate monitor or the use of other medical equipment 8. Furthermore, the cardio monitor's software, which plots the ECG curve, including ST segment shifts, can operate in the same manner as before and perform ST segment analysis in the same manner as for analyzing signals transmitted from the skin surface.

[0123] The probe 1 has an electrical signal resistance adjusted so that the signal collected from the cardiac surface can be perfectly read for a standard cardiac monitor.

[0124] The probe 1 is therefore suitable for use in ECG monitoring performed in accordance with monitoring standards used in clinical practice, and allows, using a cardio monitor equipped with standard software, automatic adjustment of the so-called ECG size (or size of the presented curve), simultaneous presentation of multiple acquired signals on the display, and analysis of cardiac ischemia (so-called analysis of the ST segment in the ECG recording).

[0125] The sufficiently long connection element 3 allows the signal cable 5 to be attached to the probe 1 and reliably prevents the signal cable 5 from entering the surgical field (thoracotomy-pericardial sac). If the signal cable 5 were attached to the probe 1 in the surgical field area, gravity could cause excessive strain on the probe 1 due to the weight of the signal cable 5 alone, potentially causing the probe 1 to fall off the cardiac surface, or there is a risk that the cable could fall into the pericardial sac, potentially injuring the patient, tearing the probe, or getting wet. Therefore, the connection element 3 of the probe 1 has a length such that the end of the probe 1 connected to the connection piece 4 is away from the surgical field, and the freely routed signal cable 5 is attached to the connection piece 4 only outside the surgical field. Preferably, the length is greater than 10 cm, more preferably approximately 17 cm. This allows the connection piece 4 to be pulled out of the patient's chest area, regardless of the position of the heart and the location where the measuring element 2 of the probe 1 is attached, to output electrical signals collected from the cardiac surface outside the surgical field.

[0126] The adhesive properties between the signal collection layer 22 and the adhesive layer 23 allow the orientation and position of the probe on the cardiac surface to be repeatedly changed by peeling the measuring element 2 from the cardiac surface and reattaching it to the cardiac surface without damaging the adhesive properties.

[0127] During testing, both the conductivity and adhesion of each layer of Probe 1 were verified, and the results are shown below.

[0128] It should be understood that the above process for manufacturing probe 1 is provided by way of example only and is not limiting of the process for manufacturing probes according to the present invention. Probe 1 can be made by any equivalent process that provides probe 1 with the structure shown.

[0129] In another embodiment, the connection element 3 transmitting the signal from the measurement element 2 may be made of any different material, including a non-flexible material capable of transmitting an ECG signal and isolated from the surgical area.

[0130] It should be noted that the terms "circular," "rectangular," "elliptical," and the like that appear in this specification are all presented as examples and do not limit the shape or configuration of the elements of probe 1.

[0131] All embodiments of the probe 1 also relate to a measurement system 6 for epicardial ECG monitoring comprising the probe 1, as explained above.

[0132] According to one embodiment of the present invention, the system 6 comprises a signal cable 5 connecting the probe 1 to a display device, for example a cardio monitor.

[0133] Probe testing of transmitted signal quality under simulated conditions In order to select the best connecting layer 32 to use in the probe 1 of the present invention, different variations of the above embodiments of the probe 1 were tested for their stability and quality in conducting signals collected under various conditions.

[0134] The test results are shown below.

[0135] Conductivity tests were conducted on the following items. a) Evaluation of the stability of the electrical conduction when changing the position of the measuring element of probe 1 on the stimulator probe; b) the ability to maintain electrical conductivity within the probe 1 during repeated deformations; c) obtaining a signal at a voltage that allows processing by a cardio monitor (the criterion being the absence of excessively high resistance to electrical conduction); d) Acquisition of a stable signal (the criterion being the absence of noise that may interfere with the acquisition of a continuous ECG recording on a cardio monitor).

[0136] experiment The electrophysiological simulator was programmed to generate electrical signals with the characteristics of a physiological sinus rhythm with a frequency of 80 beats per minute. Standard ECG electrodes for skin readings were connected to a plate with a signal output electrode. One of the electrodes was then replaced with a prototype of the probe 1 according to the present invention. The prototype was then rotated (moved) over the signal output electrode, gripped by hand, and reattached.

[0137] Thus, several variations of the probe 1 according to an embodiment of the present invention shown in Figure 4 were tested. The signal collection layer 22 and the conductive layer 32 are graphene or graphene-PMMA layers with the following composition, where graphene is one of the materials made from: -Graphene flakes from Cheap Tube, with an average diameter of 25 μm and a thickness of 10 nm; - Series M and Series H graphene flakes manufactured by XG Science (USA) with thicknesses of 2-8 nm and 15 nm, respectively, and average diameters of 5-25 μm; -Graphene flakes from Cheap Tube, with an average diameter greater than 2 μm and a thickness in the range of 8-15 nm.

[0138] Electrical testing revealed that the best electrical parameters were demonstrated by layers containing Cheap Tube flakes, and that a possible alternative would be XG Science Series M-25 flakes, which also have a highly textured or roughened layer surface, but only slightly lower electrical parameters.

[0139] result All tested prototypes of the probe 1 according to the present invention demonstrated the ability to carry out the electrocardiogram signals generated by the simulator in physiological sinus rhythm mode. Regardless of the probe 1 used, the signals were accurately presented by the electrocardiogram monitor. The signal curves were automatically and accurately calibrated by the simulator's built-in cardio monitor system (software).

[0140] In all tested models, ECG signals were best transmitted by the probe 1 according to the present invention. In the probe 1 according to the present invention, the signal collection layer 22 is a layer containing graphene flakes manufactured by Cheap Tube at a concentration of 12.5-13% by weight in a matrix, with poly(methyl methacrylate) in butyl carbitol acetate constituting 8% by weight of the carrier.

[0141] Furthermore, the following was found: a) Rotating the probe 1 according to the present invention causes slight disturbances in the display covering 1-3 ECG evolutions, which stabilize after stopping the movement (rubbing of the metal simulator electrode with the probe 1). Since ECG gel and other conductivity enhancers were not used during the tests, the disturbances may not occur at all or may be completely negligible on the surface of the beating heart. b) Repeated squeezing of probe 1 did not affect its ability to conduct signals in any of the experiments. c) No noise or other disturbances were observed during several minutes of operation with Probe 1 in a fixed position. Probe 1 functioned correctly and provided diagnostic ECG recordings.

[0142] Probe testing of adhesion using various adhesion promoters Various variations of the probe 1 according to the present invention were tested for its ability to remain on the tissue surface as the position of the probe 1 is changed, the force required to detach the probe 1 from the tissue, and the macroscopic effect (disruption of continuity) that the probe 1 has on the tissue as it is applied and detached. Force evaluations were performed manually and dynamically using a dynamometer operating in the range of 0-3 g and in the range of 0-30 g.

[0143] The test used chicken meat (chicken breast meat moistened with water at room temperature), which has a structure similar to that of cardiac muscle.

[0144] Twelve variations of the embodiment of the probe 1 shown in FIG. 4 were tested.

[0145] Model A is an embodiment of probe 1 shown in Figure 4 in which the signal collection layer 22 / adhesion layer 23 is a graphene layer, the composition of the graphene layer varying among the model variants tested.

[0146] Model B is an embodiment of probe 1 shown in FIG. 4 in which the signal collection layer 22 / adhesion layer 23 is a graphene-TPU layer and the conductive layer 32 is a graphene-PMMA layer.

[0147] Eleven prototypes of model A of probe 1 according to the invention in a given embodiment were tested, in which the measuring element 2 was 20 mm in diameter and the prototypes differed from each other in the composition of the graphene layer making up the signal collection layer 22, and one prototype of model B of probe 1, in which the measuring element 2 was 20 mm in diameter. The compositions tested are listed below. Model A: a paste of poly(methyl methacrylate) with 1.1 wt% lanolin (1 wt% lanolin + 13 wt% GNPs (graphene) + 86 wt% butyl carbitol acetate with poly(methyl methacrylate) carrier); 2.2 wt% lanolin-added poly(methyl methacrylate) paste (2 wt% lanolin + 13 wt% GNP (graphene) + 85 wt% poly(methyl methacrylate) carrier, in butyl carbitol acetate); a paste of poly(methyl methacrylate) with 3.5 wt% lanolin (5 wt% lanolin + 13 wt% GNPs (graphene) + 82 wt% butyl carbitol acetate with poly(methyl methacrylate) carrier); 4.1 wt% agar-added poly(methyl methacrylate) paste (1 wt% agar + 13 wt% GNP (graphene) + 86 wt% poly(methyl methacrylate) carrier in butyl carbitol acetate); a paste of poly(methyl methacrylate) with 5.2 wt% agar added (2 wt% agar + 13 wt% GNPs (graphene) + 85 wt% poly(methyl methacrylate) carrier in butyl carbitol acetate); a paste of poly(methyl methacrylate) with 6.5 wt% agar added (5 wt% agar + 13 wt% GNPs (graphene) + 82 wt% poly(methyl methacrylate) carrier in butyl carbitol acetate); a paste of poly(methyl methacrylate) with 7.5 wt% agar added (5 wt% agar + 13 wt% GNP (graphene) + 82 wt% butyl carbitol acetate with poly(methyl methacrylate) carrier + 2 g warm water); a paste of poly(methyl methacrylate) with 8.1 wt% sodium alginate (1 wt% sodium alginate + 13 wt% GNPs (graphene) + 86 wt% poly(methyl methacrylate) carrier in butyl carbitol acetate); a paste of poly(methyl methacrylate) with 9.2 wt% sodium alginate (2 wt% sodium alginate + 13 wt% GNPs (graphene) + 85 wt% poly(methyl methacrylate) carrier in butyl carbitol acetate); a paste of poly(methyl methacrylate) with 10.5 wt% sodium alginate (5 wt% sodium alginate + 13 wt% GNPs (graphene) + 82 wt% poly(methyl methacrylate) carrier in butyl carbitol acetate); A paste of poly(methyl methacrylate) with 11.5 wt% sodium alginate added (5 wt% sodium alginate + 13 wt% GNPs (graphene) + 82 wt% butyl carbitol acetate with poly(methyl methacrylate) carrier + 2 g warm water). Model B: 12. Thermoplastic polyurethane elastomer (TPU) paste: 10 wt% GNP (graphene) + 10 wt% Lycoat RS720 starch (hydroxypropyl starch) + 80 wt% thermoplastic polyurethane elastomer carrier in dimethylformamide (DMF).

[0148] result After applying each prototype of Probe 1 to the tissue surface, the adhesion of Probe 1 to the tissue was evaluated and it was found that Probe 1 adhered to the tissue. When the position of the tissue relative to the substrate was changed by 90 degrees without additional traction, all prototypes of Probe 1 remained on the tissue surface.

[0149] Manual evaluation of adhesive strength revealed that when Probe 1 was peeled off with forces simulating surgical manipulation on the cardiac surface, probes using lanolin failed fastest but detached too easily, regardless of the percentage content of lanolin. Probes made with agar and alginate were subjectively held more firmly, and Probe 1 made with a paste containing 5 wt% alginate was characterized by nearly ideal—as expected—adhesion and resistance to manual traction. Meanwhile, Probe 1 Model B, containing 10 wt% graphene and 10 wt% Lycoat RS720 (Sample No. 12), was characterized by the best adhesion and is therefore the most preferred embodiment of the present invention.

[0150] After dynamometric (tensile) evaluation of adhesion, several more probe peel tests were performed and the values obtained are shown below.

[0151] [Table 1]

[0152] When evaluating the macroscopic effects of applying and removing probe 1 on tissue, in each prototype case, no macroscopic tissue damage was observed with the use of the inventive probe 1. After peel force testing, none of the probe 1 prototypes broke and the signal collection layer 22 remained continuous.

[0153] The tests carried out showed that with an increase in the weight percentage of adhesive additive, the adhesive force to muscle tissue in the entire measurement area increased, and even the maximum adhesive force did not damage the tissue to which the probe 1 according to the invention was attached. During the tests, it was found that Lycoat starch (hydroxypropyl starch) showed the best adhesive properties and was also the most efficient adhesion promoter among the samples tested.

[0154] Testing the durability of probe adhesion when repeatedly attached to tissue Variants of the probe 1 according to the invention were tested for adhesion durability during subsequent application to tissue.

[0155] For the ex vivo test, chicken meat (chicken breast moistened with water at room temperature) was used, which closely resembles the myocardial structure.

[0156] One tested variation of probe 1 is probe model C of Figure 4, in which the conductive layer 32 is a layer containing silver microflakes in a biocompatible matrix, the base layer 21 is a PET film, the signal collection layer 22 / adhesive layer 23 is a graphene layer with a paste composition of poly(methyl methacrylate) with 10 wt% sodium alginate added (10 wt% sodium alginate + 13 wt% GNP (graphene) + 77 wt% butyl carbitol acetate with poly(methyl methacrylate) carrier), and the measuring element 2 is 20 mm diameter.

[0157] Another tested variant of probe 1 is a variant of the most preferred embodiment of probe 1, also shown in FIG. 4, i.e., probe model B, in which the conductive layer 32 is a "graphene-PMMA" layer containing graphene flakes manufactured by Cheap Tube, with a paste composition of poly(methyl methacrylate) (PMMA) containing 13 wt. % GNPs (graphene) and 87 wt. % poly(methyl methacrylate) carrier in butyl carbitol acetate, with an average diameter greater than 2 μm and a thickness in the range of 8-15 nm; the base layer 21 is a PET film; the signal collection layer 22, which also constitutes the adhesive layer 23, is a "graphene-TPU" layer with a paste composition of thermoplastic polyurethane elastomer (TPU) doped with 10 wt. % graphene and 10 wt. % Lycoat RS720 starch (hydroxypropyl starch); and the measuring element 2 is a 20 mm diameter "graphene-TPU" layer.

[0158] In the test, the probe 1 was attached to the tissue surface in the transverse direction—with the probe 1's surface perpendicular to the substrate and parallel to the traction force vector. This position best corresponds to the surgical situation in which the probe 1 is attached to the transverse or bottom wall of the heart during coronary artery bypass graft surgery. Using a dynamometer, the force with which the probe 1 was detached from the tissue surface was evaluated. The probe 1 was then reattached to the same location on the tissue and subjected to traction. An identical probe 1 was used in the experiment. As a control measurement, a probe 1 of the same diameter but without the adhesive layer 23 was attached to the side five times. In this way, the adhesive force generated only by the base layer 21, which provided the substrate for the measuring element 2, the connecting element 3, and the connecting piece 4, was evaluated.

[0159] Based on the results of the previous tests described above, it was determined that an adhesion force of 5 g or less was the threshold for expected retention of probe 1 on the beating heart surface, at which point probe 1 could be detached from the tissue with minimal manipulation, making this value unusable in clinical practice.

[0160] Therefore, the test will be stopped when a value of 5 g is reached, and the multiple applications performed until this value is reached will indicate the strength of the probe 1 to withstand successive applications up to the maximum number of applications of one probe 1.

[0161] Thirty applications were performed on the tissue surface, which significantly exceeds the planned number of applications on the cardiac surface during a single coronary artery bypass graft procedure. The average planned number of cardiac applications for probe 1 in the surgical setup was equal to five applications.

[0162] result In the case of Probe 1 Model C, a decrease in adhesive force of more than 30 g to 25 g was observed during the first three measurements. Then, by the ninth application, a further decrease in adhesive force was observed, down to approximately 50% of the initial value. The adhesive force then stabilized at approximately 60% of the initial adhesive force until the 15th measurement. With continued application, the adhesive force decreased to a minimum level of 7 g by the 24th application. With subsequent applications, the adhesive force improved, fluctuating around approximately 50% of the initial value. The final scheduled application (No. 30) yielded a value of 20 g. According to the protocol, the probe test was completed after 30 applications. During this experiment, the adhesive force of Probe 1 never fell below the threshold of 5 g.

[0163] In a controlled study in which the probe 1 with the base layer 21 was applied to the heart three to four times, sub-threshold adhesion forces were recorded.

[0164] In the case of Probe 1 Model B, the adhesive force remained constant for the first three measurements, fluctuating around 25 g (the exact results are shown in Table 3). Subsequently, a tendency for the adhesive force to decrease was observed, but the rate of decrease was slower than that of Probe 1 Model C. In the case of Probe 1 Model B, the adhesive force remained greater than 50% of the initial adhesive force until the final application, and only after the 20th application did the adhesive force decrease to 60% of the initial adhesive force. Furthermore, Probe 1 Model B remained stable on the cardiac surface at all cardiac wall surfaces throughout the entire expected test period, and the edges of Probe 1's measuring element 2 did not peel off from the cardiac surface.

[0165] The values obtained during tests carried out on model C of probe 1 with signal collection layer 22 attached to the heart and model B of probe 1 with signal collection layer 22 attached to the heart are given below.

[0166] [Table 2]

[0167] [Table 3]

[0168] During testing, Probe 1 according to the present invention maintained the expected level of adhesion for 30 tissue applications, regardless of the model tested. For Probe 1 Model B, after the fourth or fifth application, Probe 1 exhibited a decrease in adhesion to approximately 50-60% of its initial value, which exceeds the minimum required to maintain Probe 1. Meanwhile, Probe 1 Model B maintained adhesion greater than 50% of its initial value for up to 30 applications, but only observed a 20% decrease in adhesion, i.e., to a level of 80% of its initial value, after the fourth or fifth application. Furthermore, Probe 1 did not lose its functionality during the subsequent 30 applications, as the adhesion values of Probe 1 for both models of probe embodiment did not exceed the minimum required value. Furthermore, when the results of a test in which probe 1 having signal collection layer 22 was attached to tissue were compared with the results of a test in which probe 1 having base layer 21 was attached, it was observed that model C of probe 1 including signal collection layer 22 had an adhesive strength that was 3 to 6 times greater than when probe 1 having base layer 21 was attached to tissue.

[0169] Adhesion durability test after probe disinfection Model B of Probe 1, which is the most preferred embodiment of Probe 1 according to the present invention, was irradiated with gamma rays, and the maintenance of adhesive strength of Probe 1 after irradiation was evaluated. The results are shown in the table below, in comparison with the adhesive strength results of Probe 1 before irradiation shown previously.

[0170] [Table 4]

[0171] The test results clearly demonstrate that gamma irradiation does not reduce the adhesive properties of model B of probe 1 according to the present invention. After disinfection, the model remained stable on the cardiac surface for the entire expected period of time for all cardiac wall surfaces. Since there was no loss of adhesive strength upon positional changes or loss of flexibility of model B of probe 1, the probe according to the present invention can be properly disinfected and used for medical applications. Furthermore, because it has the best adhesive properties, model B of probe 1 is the preferred embodiment of probe 1 according to the present invention. However, it should be understood that the designation of the most preferred embodiment of the probe is intended to emphasize the adhesive properties of the variant and does not exclude the use of the other above-mentioned variants of the probe.

[0172] After the irradiation, under the same conditions, a partial test of the probe's adhesion, as well as a test of signal continuity and the presentation of signal recordings on a cardio monitor (checking the interaction of Probe 1 with the cardio monitor) were also performed. Probe 1 Model B, previously irradiated with gamma radiation at a dose used for sterilizing medical devices, accurately conducted electrical signals from the cardiac surface, but no differences were observed in signal conduction between various subsequent positions of the measuring element 2 on individual cardiac walls; the probe did not change its conduction capabilities over time or with changes in position. Furthermore, after irradiation, Probe 1 Model B accurately interacted with the cardio monitor, and the signal presented on the monitor in auto-adjust mode was accurately adjusted and did not deviate from the measurement limits. This confirms that Probe 1 Model B maintains the diagnostic properties necessary for the diagnostic use of ECG recordings for the assessment of cardiac ischemia.

[0173] Probe biocompatibility Model B of the probe 1 according to the invention, which is considered to be the most suitable variant of one embodiment of the probe 1 according to the invention based on the above tests, was further subjected to biocompatibility tests, namely cytotoxicity tests and irritation tests carried out in accordance with the ISO EN ISO10993-5 and EN ISO10993-10:2015 standards.

[0174] The results of the above test showed that model B of probe 1 according to the present invention can be used safely on the cardiac surface, and at the same time, it remains stably on the cardiac surface, confirming the possibility of detecting cardiac ischemia.

[0175] All embodiments and their variations are described only as non-limiting indications of the present invention and in no way limit the scope of protection defined by the claims. It should be understood that any technical solution used in the probe of the present invention can be implemented by equivalent techniques without exceeding the scope of protection.

Claims

1. a measuring element for measuring an electrical signal from the heart; and a connecting element configured to output the measured cardiac signal through a connecting piece; the measuring element is electrically connected to the connecting element, and the measuring element is a laminated element including a signal collecting layer positioned over at least a portion of the measuring element and a base layer extending over the entire surface of the measuring element; the connection element is a laminated element including a conductive layer, a dielectric layer insulating the conductive layer, and the base layer extending over the entire surface of the connection element, the signal collecting layer of the measuring element is an adhesive layer capable of fixing a probe to the heart, and includes at least one carrier, a conductive material, and at least one adhesion promoter; the connecting piece provided at the end of the connecting element opposite to the measuring element is a laminated element including the conductive layer and the base layer, The measuring element has a maximum dimension perpendicular to the thickness direction of 30 mm, In the measuring element, the adhesive layer is a graphene-TPU layer; A probe for epicardial ECG monitoring, comprising:

2. 2. The probe of claim 1, wherein the measuring element between the signal collection layer and the base layer comprises the conductive layer, while the connecting element has the conductive layer disposed on the dielectric layer and the base layer positioned on the conductive layer, and the conductive layer of the measuring element and the conductive layer of the connecting element form a continuous conductive layer extending across the measuring element and the connecting element.

3. 2. The probe of claim 1, wherein in the measuring element, the base layer is located on the signal collection layer, and in the connecting element, the base layer is located on the conductive layer, and the conductive layer is disposed on the dielectric layer.

4. 2. The probe of claim 1, wherein in the measuring element, the base layer is located on the signal collection layer, and in the connecting element, the base layer is located on the conductive layer, and the conductive layer is disposed on the dielectric layer, and the signal collection layer of the measuring element and the conductive layer of the connecting element form a continuous layer extending across the measuring element and the connecting element.

5. 2. The probe of claim 1, wherein in the measuring element, the base layer is located on the signal collection layer, while in the connecting element, the conductive layer is disposed on the dielectric layer and the base layer is located on the conductive layer, the conductive layer of the connecting element in a portion adjacent to the measuring element is made of the same material as the signal collection layer of the measuring element, and the remaining portion is made of a different conductive material.

6. 10. The probe of claim 1, wherein the adhesive layer comprises a polymer and an adhesion promoter.

7. 2. The probe of claim 1, wherein in the measuring element, the graphene TPU layer comprises graphene, hydroxypropyl starch, and a thermoplastic polyurethane elastomer in dimethylformamide.

8. 8. The probe of claim 7, wherein the graphene-TPU layer comprises 10% by weight graphene, 10% by weight hydroxypropyl starch, and 80% thermoplastic polyurethane elastomer in dimethylformamide.

9. The probe of claim 1 , wherein the conductive layer in the connection element is a graphene layer.

10. 2. The probe according to claim 1, wherein the conductive layer in the connection element is a graphene-PMMA layer containing graphene and polymethyl methacrylate in butyl carbitol acetate.

11. The probe of claim 1 , wherein the signal collection layer in the measuring element is a graphene layer.

12. 2. The probe of claim 1, wherein the measuring element and the connecting element are located in the same plane.

13. 2. The probe of claim 1, wherein said dielectric layer and said base layer are made of the same material.

14. 2. The probe of claim 1, wherein the connecting element is connected to a signal cable through the connecting piece.

15. 2. The probe of claim 1, wherein the adhesion promoter comprises one substance selected from lanolin, agar, sodium alginate, collagen, gelatin, starch and cellulose, and derivatives thereof including carboxymethylcellulose, carboxymethylstarch, or hydroxypropylstarch, or mixtures thereof.

16. The conductive material is Au, Ag, PdAg, graphite, graphene, or RuO ２ , IrO ２ , Bi ２ Ru ２ O ７ 2. The probe according to claim 1, wherein the conductive material is at least one selected from the group consisting of ITO, ITO, and a mixture thereof.

17. the carrier is a polymer compound containing a solvent or a resin containing a solvent, the polymer of the adhesive layer is one selected from ethyl cellulose, polypropylene, polyethylene, polyester, polystyrene, polymethyl methacrylate (PMMA), thermoplastic polyurethane elastomer (TPU), polylactic acid (PLA), and mixtures thereof; 2. The probe according to claim 1, wherein the solvent is one selected from the group consisting of acetone, dimethylformamide (DMF), butyl carbitol acetate (OKB), chloroform, and mixtures thereof.

18. 2. The probe according to claim 1, wherein the base layer is made of one material selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polycarbonate (PC), polyethersulfone (PES), polyarylate (PAR), polycyclic olefin (PCO) or polynorbornene (PNB), polyimide (PI), fluorine polyester, or a copolymer thereof.

19. 2. The probe of claim 1, wherein the thickness of the dielectric layer, the signal collecting layer, and the conductive layer is in the range of 10 to 15 μm.

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