A device for measuring and recording ventricular compression force, and a method for measuring and recording compression force.

Abstract

The present invention provides a device for measuring and recording the compressive force applied by the inner surface of the ventricular wall, and a method for measuring and recording this compressive force. [Solution] A device (1) for measuring and recording the compressive force applied to the ventricle by the inner surface of the ventricular wall, the device (1) comprising a stabilization system (2) from which at least one measuring arm (3) extends, and a sensor (9) mounted on the measuring arm (3). The device (1) has a spatial design adapted to the interior of the left ventricle and allows for multi-point contact with the endocardial surface. Also, a computer implementation method for measuring and recording the compressive force measured using the device (1) for measuring and recording the compressive force of the ventricle.

Description

Technical Field

[0001] The subject of the present invention is a device for measuring and recording the compressive force exerted by the inner surface of the ventricular wall, as well as a method for measuring and recording this compressive force.

Background Art

[0002] The function of the heart involves a series of events associated with the rhythmic deformation of the ventricles and atria that generate suction or compressive forces depending on the phases of systole or diastole. The compressive force of the ventricles is caused by the contraction of the ventricles associated with a rapid reduction in their internal volume. As a result, blood from the ventricles moves into the arteries, which is the pulmonary artery in the case of the right ventricle and the aorta in the case of the left ventricle. During this time, the atria are passively filled with venous blood, and at the end of the diastolic phase, they actively replenish the volume of the dilated ventricles, thus completing the cardiac cycle. From a mechanical perspective, ventricular systole is divided into two phases: the isovolumetric phase and the isotonic ejection phase, while diastole consists of four phases: the isovolumetric relaxation phase, the early filling phase, the slow filling phase, and the atrial filling phase.

[0003] Under physiological conditions, the load on the ventricular muscle is at a minimum, which is related to the fact that only a part of the range of sarcomere shortening (the functional unit of striated muscle) is used to generate the tension that balances the load resulting from the blood volume, and the remaining range of sarcomere shortening is used to perform external work. The left ventricle pumps blood flow into the aorta and blood vessels and performs a mixed isotonic contraction with a secondary load. The more the range of sarcomere shortening used for ejection and the less the range of sarcomere shortening used for myocardial tension, the more favorable the hemodynamic and energetic conditions in the muscle become.

[0004] In isometric contraction, the measure of contractile ability is the maximum tension generated by the muscle, which depends on the resting stretch of the ventricle, i.e., the preload. In turn, the measure of isotonic contraction is the shortening velocity, which depends on the afterload.

[0005] The pressure within the cardiac chambers exerts a force on the ventricular walls, and this force is balanced by wall tension. When the walls are thick, the tensile stress is distributed across a greater number of cardiomyocytes (myocardium cells); when the walls are thin, the stress is distributed across a smaller number of cardiomyocytes. Wall stress is a measure of the elongation of individual cardiomyocytes.

[0006] The mechanical function of the myocardium is closely related to the generation of electrical impulses. For this reason, one of the methods used to diagnose cardiac function is to measure changes in electrical potential. The most common diagnostic technique based on electrical phenomena occurring in the heart is electrocardiography, in which the cardiac cycle is described by a graph consisting of waves showing changes in electrical potential. Another common method, namely echocardiography, is associated with determining the mechanical and fluid function of the heart using ultrasound techniques. In a clinical setting, circular stress is determined based on echocardiographic measurements of the left ventricular short-axis radius and ventricular wall thickness. The load on cardiomyocytes in the wall increases with increasing blood pressure and increasing ventricular radius, and becomes greater as the ventricular wall thins. Stress correlates well with oxygen consumption per gram of myocardium, indicating that it is a good measure of the load on individual cardiomyocytes. For practical reasons, it is estimated only at the beginning and end of isovolumetric contraction. However, there is no data on the direct measurement of mechanical stress and tension of the ventricular wall, particularly in cases of cardiac dysfunction, such as during myocardial infarction.

[0007] A crucial aspect of heart function is the effective movement of blood into the arteries by applying compressive force to the blood filling the ventricles, ensuring proper filling of the entire system. An indirect method that allows for accurate determination in this regard is the measurement of arterial pressure in two ranges: the so-called systolic pressure, physiologically around 120 mmHg in adults, and the diastolic pressure, with an average value of approximately 80 mmHg. This measurement is performed at a certain distance from the heart (usually on the brachial artery), which introduces numerous confounding factors. One such factor is the resistance of the arterial wall to the flowing blood. Therefore, arterial pressure measurements do not fully reflect the actual compressive force of the myocardium and the distribution of these forces within the ventricles.

[0008] Given the highly complex nature of ventricular contraction, performing such measurements is extremely difficult. During systole, the ventricle not only linearly decreases its volume but also completely alters its external and internal geometric shape through the twisting motion of the ventricular wall muscle. This type of contraction allows for a more efficient use of energy stored in the cells, and thanks to the use of additional energy associated with the change in geometric shape involving the twisting of the ventricle along its long axis, it generates the maximum pressure force with the least effort. The evolutionary process of the heart has led to its anatomical and histological structure, as well as its physiological and motor functions, being adapted to the most efficient pumping of blood, with the greatest possible reduction in effort and energy consumption required to maintain its continuous and long-term function. However, the solutions that nature has developed for the efficiency and endurance of the myocardium have significantly complicated the diagnosis of some elements of its function. It should be assumed that the forces exerted by certain regions on the inner surface of the ventricular wall are greater than those exerted by other regions and are greater than the average force across the entire surface. This uneven force distribution can consequently lead to uneven loading of myocardial fibers and faster "wear and tearing" of certain areas, but these have been appropriately reinforced during the process of evolutionary adaptation. It appears possible to determine such diverse areas and force distribution patterns on the inner surface of the ventricular wall by using appropriate multi-point measurement systems. Based on such developed models, it becomes possible to expand existing diagnostic possibilities by considering deviations from the normal force distribution within the working ventricle, potentially allowing for the identification of areas with increased risk of muscle fiber debilitation or hypertrophy, or impairment of their motor function.

[0009] In this invention, a dynamometer known in mechanics is used to determine the value of the compressive force generated by the ventricular wall during contraction. These dynamometers are elements equipped with special sensors that record the value of the deformation caused by the force to be measured. If the deformation is elastic, the force is determined by Hooke's Law. σ = ε * E The calculation is performed using the formula, where σ is the stress defined as the force F acting on the surface S, ε is the deformation defined as the change in geometric shape, for example, the change in length Δl in the case of one-dimensional deformation, and E is Young's modulus (material constant). Therefore, the required force is F=(ε*E) / S That is the case.

[0010] There are several methods that can be used to measure deformation, but the most common method is based on electrical resistance tensometry, where the deformation ε of the element being measured causes a change in its geometric shape ΔI, which in turn causes a change in its electrical resistance ΔR. This relationship is expressed by the equation ΔR / R = k*ε This is described by the equation, where k is the strain gauge constant. Therefore, by recording the change in resistance, the deformation value can be determined, and as a result, the stress value, and consequently the force causing this deformation, can be determined.

[0011] In the prior art, for example, from Patent EP 0 473 070 B1, a system for myocardial tensometry incorporated into an implantable electrotherapy device for measuring myocardial contraction is known. This system includes a single strain gauge element positioned at a location subject to bending due to cardiac contraction, the strain gauge element comprising a piezoelectric material or a variable resistive material, and the mechanical stress acting on the strain gauge element causes a change in voltage or resistivity in the element that is comparable in frequency and amplitude to cardiac contraction.

[0012] Another known solution from the prior art is the invention described in patent US 6 600 948 B2. The object of this invention is to enable simultaneous measurement of physiological signals by multiple sensors in the human body, for example in the heart, while providing accurate measurement of at least the relative position of all sensors, thereby enabling mapping of electrical activation time in the myocardium. In one embodiment of this invention, the sensors are attached to a catheter, more specifically, multiple sensors / electrodes are attached to the distal end of a catheter inserted into the heart. In one embodiment, the sensors are strain gauges useful for determining myocardial contraction.

[0013] Prior art lacks solutions that provide measurement of the actual compressive force on the ventricles and the force distribution within the inner surface of the ventricular wall. Such information would provide accurate information about the characteristics of myocardial function through direct measurement, which could significantly increase the scope of diagnostic possibilities for both scientific purposes associated with the study of the anatomical and physiological characteristics of the heart, and for medical practice involving the diagnosis, prevention, and treatment of cardiac failure, which is the most common cause of death. [Overview of the Initiative]

[0014] Taking into consideration the existing shortcomings of the prior art, the applicant has developed the solutions according to the attached independent claims 1 to 16, which enable the determination of the aforementioned forces and their distribution. According to these solutions, the applicant has developed a device that enables the measurement and recording of ventricular compressive forces and the collection of these measurements, as well as a method for measuring and recording ventricular compressive forces. Possible embodiments of this device are presented in dependent claims 2 to 15. The device can be inserted into a suitable ventricle to monitor the function of the heart by measuring and recording compressive forces, and the method enables monitoring, recording, and processing of measurements from the device.

[0015] A device for measuring and recording the compressive force applied by the inner surface of the ventricular wall, wherein the device comprises a stabilization system to which at least one flexible measuring arm extends, the proximal end of the flexible measuring arm being connected to the stabilization system, the distal end being in contact with the endocardium of the left ventricular wall, the device having a spatial structure adapted to the interior of the left ventricle and enabling multi-point contact with the endocardium surface, the flexible measuring arm deforms with the contraction and expansion of the left ventricle, and the flexible measuring arm is provided with a sensor for measuring the deformation of the flexible measuring arm, which reflects the compressive force of the cardiac wall on the interior of the left ventricle.

[0016] Preferably, the device for measuring and recording ventricular compression force comprises a stabilization system for maintaining a stable position of the device within the left ventricle, the stabilization system comprising a stabilizer and a core extending centrally along the long axis of the left ventricle, with one end at the apex of the heart and the other end in the region of the aortic valve.

[0017] Preferably, the sensor is a strain gauge sensor.

[0018] Preferably, the flexible measuring arms attached to the core of the stabilization system are arranged radially with respect to the long axis of the left ventricle at equiangled intervals from each other and at at least two levels, the lengths of which are adapted to the levels, and ensuring attachment to the periapical and central segments of the left ventricle.

[0019] Preferably, the contact point where the flexible measuring arm contacts the endocardium is non-traumatic, ensuring deformation of the flexible measuring arm during contraction without risking damage to the endocardium.

[0020] Preferably, the flexibility measuring arm terminates with one of a loop, a ball, or a spherical mesh.

[0021] Preferably, the sensor located on the flexibility measuring arm is positioned as close as possible to the proximal end of the flexibility measuring arm.

[0022] Preferably, the flexible measurement arm is made of a material that allows it to bend under the influence of contraction and unbend to its rest position during diastole of the left ventricle without interfering with the natural function of the left ventricle, the flexible measurement arm is made of a material that enables its visualization, and / or includes at least one marker that enables its visualization.

[0023] Preferably, each flexible measurement arm has dimensions that allow a sensor to be mounted thereon.

[0024] Preferably, the stabilization system further includes a stabilization guide that terminates at a curved portion at the apex of the heart, preferably, the curved portion that terminates the stabilization guide is J-shaped, and the stabilizer of the stabilization system is an O-shaped loop.

[0025] Preferably, the sensor is connected to a resistor system for the sensor that forms a Wheatstone bridge, and the Wheatstone bridge, together with a voltmeter, forms a measurement system that generates an electrical signal corresponding to the bending force of the flexible measurement arm, the measurement system is connected to a microcontroller, and the data collected by the sensor is transmitted to the microcontroller.

[0026] Preferably, the element that transmits the measurement signal from the individual measurement systems to the microcontroller is installed along a core that is centrally located on the long axis of the left ventricle.

[0027] Preferably, the microcontroller has a number of active channels that allow simultaneous collection of signals from all the measurement systems of the device and receives at least one additional auxiliary signal from other diagnostic devices.

[0028] Preferably, each flexible measurement arm indicates a single point value of the compressive force acting on the inner surface of the ventricular wall.

[0029] Preferably, the flexible measuring arm and stabilization system elements are foldable and housed within a catheter inserted into the heart, the flexible measuring arm and stabilization system elements take on a measurement position after the catheter slides off from the flexible measuring arm and stabilization system elements within the left ventricle, the distal end of the flexible measuring arm then contacts the endocardium of the left ventricular wall, and after the measurement is complete, the flexible measuring arm and stabilization system elements are folded, the catheter slides over them so that the flexible measuring arm and stabilization system elements are housed within the catheter, and then the catheter is removed from the left ventricle to the outside.

[0030] A computer-implemented method for measuring and recording ventricular compressive force using a device for measuring and recording ventricular compressive force according to the present invention, wherein when there is no compressive force, the sensor remains in a resting position and the measurement system shows a voltmeter value of 0, and when a compressive force is applied, the sensor deforms and the measurement system shows a voltmeter value other than 0, where this value is proportional to the resistance R of the sensor, and this makes it possible to determine the compressive force exerted by a specific region of the ventricular wall that the flexible measuring arm of the device contacts during contraction and diastole by converting the recorded voltage into a value of compressive force.

[0031] Table 1 below provides definitions of terms used in this explanation to facilitate understanding of the structure and function of this device.

[0032] [Table 1]

[0033] An exemplary implementation of the device for measuring and recording ventricular compression force according to the present invention is shown in the drawings, where this implementation and its presentation are intended to facilitate an understanding of the structure and operation of the device for measuring and recording ventricular compression force, but it is not the only possible implementation of the present invention. [Brief explanation of the drawing]

[0034] [Figure 1a] Figure 1a shows a device according to one embodiment of the present invention for measuring and recording ventricular compression force in the deployed position. [Figure 1b] Figure 1b shows a device placed inside the heart during the diastolic phase for measuring and recording ventricular compression forces from Figure 1a. [Figure 1c] Figure 1c shows a device placed inside the heart during cardiac contraction to measure and record the ventricular compression force from Figure 1a. [Figure 2a] Figure 2a shows a top view of the device used to measure and record the ventricular compression force from Figure 1a. [Figure 2b] Figure 2b shows a top view of a device for measuring and recording ventricular compression force according to one embodiment of the present invention, in which the arms at these levels are not identically positioned. [Figure 3a] Figure 3a shows the device for measuring and recording ventricular compression forces from Figure 1a, with each component labeled. [Figure 3b] Figure 3b shows a diagram of the arm of the device for measuring and recording ventricular compression force from Figure 1a. [Figure 4] Figure 4a shows the arm of a device having an initial-length strain gauge sensor attached to the core, Figure 4b shows the arm of the device deforming under the action of a compressive force, and Figure 4c shows a comparison of the strain gauge length before and during the application of the compressive force. [Figure 5] Figure 5 shows the structure of a measurement system including sensors for measuring deformation. [Modes for carrying out the invention]

[0035] Device 1 for measuring and recording the compressive force applied by the inner surface of the ventricular wall, according to embodiments shown in Figures 1a, 1b, and 1c and Figures 3a and 3b, comprises a stabilization system 2 from which flexible measuring arms 3 extend, the proximal end of each arm 3 being connected to the stabilization system 2 and intended to stabilize the position of the device in the left ventricle, and the distal end of each arm 3 abutting against the endocardium of the left ventricular wall of the heart. Each arm 3 is equipped with a sensor for measuring the deformation of the arm 3, which reflects the compressive force of the heart wall against the interior of the ventricle. The design of device 1 is spatial, so that device 1 conforms to the interior of the left ventricle while allowing multi-point contact with the endocardial surface, as shown in Figure 1b. When installed in the left ventricle and in its target position, the design of device 1 for measuring and recording ventricular compressive force has the shape of an inverted Christmas tree.

[0036] The stabilization system 2 comprises a guide 6, a stabilizer 5, and a core 4 in the form of a hollow tube extending centrally along the long axis of the left ventricle from the left ventricular outflow tract to the apex. In other words, one end of the core 4 is located in the left ventricle directly below the aortic valve and may be called the “upper” or “proximal” end of the core 4, and the other end of the core 4 is located near the apex of the heart and may be called the “lower” or “distal” end. The core 4 is linear and preferably rigid and is fitted to receive the guide 6 in its hollow space, the guide 6 being attached to the proximal part of the core 4 by a sleeve 7 that securely fixes the guide 6. Furthermore, in exemplary embodiments, the guide 6 is stabilized inside the core 4 by clamping the core 4 onto the guide 6 in a space between levels. The guide 6 extends axially along the entire length of the core 4, exits the core 4 distally, terminates there at an upwardly curving section, extends beyond the core 4, extends below the lower edge of the stabilizer 5, and also exits the core 4 proximal to extend over a certain distance. In one embodiment, the guide 6 consists of two separate, unconnected wires, namely a guide wire and a stabilizing wire. At the distal end of the core 4, the stabilizing wire protrudes beyond the core 4, forming the distal end of the guide 6, terminates at the aforementioned curving section, and is positioned at the apex of the left ventricle. In this embodiment, the guide 6 is fixed within the core 4 as follows: the stabilizing wire of the guide 6 is inserted into the core 4, which is provided with the arm 3, so that its distal end protrudes from the distal end of the core 4 as described above, while its proximal end protrudes beyond the upper end of the core 4. Next, the core 4 is clamped onto this stabilizing wire between the lower level arms 3, and the guide wire is then inserted up to this clamp, so that the guide wire protrudes beyond the core 4 at the proximal end of the core 4, and additionally, the guide wire is secured to the proximal end of the core 4 by the sleeve 7. In this embodiment, the guide wire of guide 6 does not extend to the distal end of the core 4, but only to a portion of the length of the core 4, for example, to the portion of the core between the levels of the arms 3. At the proximal end of the core 4, both wires constituting guide 6 are housed within a common biocompatible protective sheath.

[0037] The stabilizer 5 is in the form of a loop used to stabilize the position of the device 1 within the heart, that is, together with the arm 3, to prevent undesirable movement and displacement of the device 1 within the ventricle, and if the curves of the stabilizer 5 and guide 6 are considered to be two-dimensional elements (without thickness), then the stabilizer loop 5 extends in a plane other than the curve of the guide 6. For example, if the curve of the guide 6 extends in the XZ plane, where Z is the axis that coincides with the axis of the core 4 in the Cartesian coordinate system and the other axes are perpendicular to it, then the stabilizer loop 5 may extend in the YZ plane, for example (in this case the angle between the plane of the curve of the guide 6 and the stabilizing loop is 90 degrees).

[0038] The curved portion terminating the guide 6 may have a different shape, for example, it may be J-shaped, as shown in Figures 1a, 1b, and 3a.

[0039] Alternatively, the curved section terminating guide 6 may be O-shaped, which surrounds the lower part of the stabilization loop, thereby providing further stabilization of device 1.

[0040] In alternative embodiments, the curved portion terminating the guide 6 may have a different shape, as long as it is non-traumatic, i.e., does not pose a risk of endocardial damage.

[0041] The flexibility measuring arm 3 of device 1 extends from the stabilization system 2, or more precisely, from the core 4 of this system, with the proximal end of arm 3 located closer to the core 4 and the distal end of arm 3 located further away from the core 4.

[0042] The flexible measuring arms 3 attached to the core 4 of the stabilization system 2 are arranged radially with respect to the long axis of the left ventricle, and in one embodiment, these flexible measuring arms 3 are positioned at two different levels, i.e., at different locations along the length of the core 4, at equal angular distances from each other, i.e., the distance from the upper end of each of these levels is different. It can be assumed that the core 4 is divided into several sections in a vertical arrangement, and each section has several arms 3 arranged concentrically in a star arrangement.

[0043] According to the embodiments shown in Figures 1a, 1b, and 1c, the device 1 comprises six flexible measuring arms 3 on two levels, resulting in three arms on each level. The arrangement of the arms 3 on each of these levels may be identical or different, as shown in Figure 2a, or they may be the same in terms of the spacing between the arms 3 (their angular distance from one another), but different in terms of the position of the arms 3 in the XZ plane, as shown in Figure 2b, where Z is the axis that coincides with the axis of the core 4 in the Cartesian coordinate system, i.e., when the device 1 is viewed "from above" and "downward" from the top of the core 4, the arms 3 on each level do not "overlap" but are shifted relative to one another.

[0044] In an alternative embodiment, the arms 3 may be positioned at more than two levels, and the number of them per level may vary and be arbitrary, but preferably, the device 1 comprises at least two flexible measuring arms 3 fixed at at least two levels to provide at least two different contact points with the endocardium, and thus at least two measurement points.

[0045] While it is possible to fabricate a device 1 containing one flexible measuring arm 3, it would not provide a satisfactory number of measurements. The number of levels depends on the size of the left ventricle of the heart being examined, which will be explained in more detail below.

[0046] For example, the device may have five arms arranged on two levels, or nine arms arranged on three levels, or any other feasible combination.

[0047] The length of the flexible measuring arms 3 is adapted to the dimensions of the level in which they are located and the geometric shape of the ventricle, thereby ensuring that their length is such that they adhere to the periapical and central segments of the left ventricle, i.e., they provide contact points for the flexible measuring arms 3 with the endocardium; the width of the flexible measuring arms 3 ensures the free positioning of the sensor 9 on the flexible measuring arms 3; and the thickness of the flexible measuring arms 3 is determined by the thickness of the material from which the arms 3 are fabricated.

[0048] Each contact point of the flexible measuring arm 3 with the endocardium is non-traumatic, meaning there is no risk of endocarditis damage when the measuring arm 3 is deformed during cardiac contraction. As shown in Figures 1a and 1b, and also in Figure 3b, such terminations have the form of a loop; however, alternatively, the flexible measuring arm 3 may be terminated with a spherical mesh and / or ball, but based on the tests performed, terminating the measuring arm 3 with a loop proved to be the most advantageous.

[0049] For example, as shown in Figures 4a, 4b, and 4c, each measuring arm 3 deforms along with the ventricular systole and diastole; in other words, during ventricular contraction, a compressive force F acts on the measuring arm 3, bending it, which changes the length of the sensor 9 from its initial length l0 to length l1, where l1 differs from l0 by Δl. Each arm 3 of the device 1 is curved at its proximal end, so that the proximal end of the arm 3 itself extends substantially parallel to the core 4, which facilitates mounting the arm 3 to the core 4 by a sleeve 8 for mounting the arm 3. In the example shown in Figures 3a and 3b, the distal end of the arm 3 terminates with a loop that abuts against the cardiac wall, and the sensor 9 is mounted on the upper or lower surface of each arm 3. In embodiments where the sensor 9 is located on the underside of the arm 3, the resulting deformation values ​​are the same except for the negative sign, and the value itself is important for reading the compressive force. In the example of the embodiment, the sensor 9 is a strain gauge sensor that enables the measurement of deformation of the measuring arm 3, which reflects the compressive force of the cardiac wall against the interior of the ventricle. The strain gauge sensor 9 is located as close as possible to the core 4 and on the upper part of the arm 3 that is not covered by the mounting sleeve 8. Preferred embodiments of the arrangement of the strain gauge sensor 9 and the arm 3 are shown in Figures 3a and 3b.

[0050] The flexible measuring arm 3 may be of different lengths at different levels to allow the device 1 to better conform to the shape of the left ventricle. Generally, the dimensions of the human left ventricle in the short axis at the base of the ventricle during diastole range from 38 to 60 mm in healthy individuals. In people after a heart attack, the dimensions of the ventricle are individually and variably enlarged, reaching 70 to 80 mm in the short axis at the base in extreme cases. In healthy individuals, the long axis dimension of the left ventricle during diastole ranges from 50 to 100 mm, depending on sex and age. Therefore, the size of the device 1 according to the present invention must be adapted to the intended size of the left ventricle. In other words, the device 1 according to the present invention may be manufactured in several sizes, thereby making it possible to select a size suitable for the dimensions of an individual heart.

[0051] The dimensions of device 1 for measuring and recording ventricular compression force are no more than 100 mm along the long axis of the ventricle (the total length of the core 4, the stabilizing loop 5, and the portion of the guide 6 that protrudes beyond the core 4 distally, excluding the length of the guide 6 that protrudes beyond the ventricle from the core 4 proximally), and no more than 65 mm along the short axis (axis perpendicular to the long axis) at the most proximal level, i.e., the level closest to the base of the heart. The length of a single flexible measuring arm 3 may range from 10 to 45 mm. The core 4 may have a length of 35 to 45 mm, an outer diameter of 0.50 to 1.00 mm, and a wall thickness of 0.1 to 0.2 mm. The stabilizer 5 may have a loop diameter of 25 mm, while the portion of the guide 6 that protrudes beyond the lower edge of the loop of the stabilizer 5 extends 5 to 10 mm below the loop.

[0052] The length of the guide 6 that protrudes beyond the core 4 from the proximal side of the core 4 depends on the point of introduction of the device 1 into the body. In the case of carotid artery access, the length of the guide 6 will be shorter than in the case of femoral artery access. In principle, the guide 6 must be long enough to protrude beyond the (cardiac) catheter into which the device 1 is introduced in the portion extending from the proximal part of the core 4 to the insertion point, which means that for a 1200 mm catheter, the total length of the guide 6 is approximately 1600 mm, for example, 1500 mm.

[0053] Typically, considering the average statistical dimensions of the human ventricle, the number of levels with arms 3 will be two or three, and the preferred number of arms 3 on a single level is three to five. The distance between levels in two positions will be 30-40 mm, and the distance from the apex of the heart for levels closer to the apex will also be approximately 30-40 mm. An asymmetrical arrangement of arms 3, i.e., an implementation of device 1 with an odd number of arms 3 on one level, is advantageous due to the need to prevent mutual interference of the measuring arms 3.

[0054] Basically, the number of levels of the device 1 where the flexible measuring arm 3 with strain gauge 9 is positioned during use, as well as the number of arms 3 at a single level, are selected according to the size of the ventricular cavity. In other words, the person selecting the appropriate device 1 for measuring and recording compressive force will select the device 1 from the available sizes that will provide the best fit for a given left ventricle, i.e., the device 1 will provide the aforementioned contact points, and the left ventricular size will be determined during ultrasound or any other appropriate imaging test.

[0055] The longitudinal dimensions of the flexible measuring arm 3 of device 1 for measuring and recording compressive force may be, for example, 25-35 mm at the lower level and 30-35 mm at the upper level. The transverse dimensions of the arm 3 must allow for the mounting of a sensor 9 on each arm, and typically the width of the arm is 0.814 mm and its thickness is 0.153 mm. In embodiments having three arms 3 per level, the angular distance between the arms 3 is 120 degrees. The proximal end of each arm 3, perpendicular to the core 4 by a bend to ensure adhesion to the core, is 5 mm and covered by a sleeve 8.

[0056] As described above, the sensor 9 is provided on each flexible measuring arm 3, and the sensor is positioned as close as possible to the proximal end of the measuring arm 3, ensuring that it does not interfere with the deformation of the flexible measuring arm 3 during contraction, thereby providing the most accurate measurement values.

[0057] Each sensor 9 of device 1, such as a strain gauge, is connected to its own resistor system that forms a Wheatstone bridge, which, together with a voltmeter, forms a measurement system that generates an electrical signal corresponding to the deflection force of the measuring arm 3. In the embodiment shown in Figure 3a, one strain gauge sensor 9 is installed on each of the six flexible measuring arms 3, and the rest of the measurement system for each arm is located outside the patient, and the measurement system is connected to a microcontroller located outside the patient, and the data collected by the strain gauge sensor 9 is transmitted to this microcontroller by an element that transmits the measurement signal, in particular by a wire capable of transmitting the signal, such as a copper wire with a diameter of 0.04 mm.

[0058] The signal-transmitting wires are combined into a common bundle of wires and extend along the core 4 of device 1, on its outside, upward from the strain gauge 9, leading this bundle out of the left ventricle, through the peripheral arteries, out of the body, and to a male VGA plug, which is connected via a suitable system of amplifiers and transducers to a microcontroller located outside the patient and equipped with a female VGA plug. In one modification, the microcontroller is connected to a wire that collects signals time-synchronized with the signals flowing from the strain gauge sensor 9, such as from an ECG from the patient's surface, forming an objective reference system for interpreting the strain gauge measurement results.

[0059] In an alternative embodiment, the signal-transmitting wire is inserted into the core 4, extends upward along the core 4, and is then routed away from the patient, either together or bundled into a single common wire, as in the embodiments described above.

[0060] Each wire or wire bundle is covered with a shield, preferably a thin-walled polymer protective and insulating tube.

[0061] The microcontroller has several active channels, for example, six channels in Figure 5, enabling simultaneous acquisition of signals from all measurement systems of device 1 and receiving at least one additional auxiliary signal from other diagnostic equipment. The acquired signals are then transmitted to an external device, such as a receiving and recording station.

[0062] To ensure the safe insertion of device 1 into the left ventricle and its operation within the ventricle, device 1 must be fabricated, at least partially, from a flexible material that allows it to be folded, placed within a catheter, then advanced within the transport catheter, and unfolded after being withdrawn from the catheter. In other words, device 1 must be fabricated from a material characterized by a very wide range of elastic deformation, high strength parameters and fatigue resistance, a relatively low Young's modulus, and a narrow or zero range of plastic deformation. In addition, device 1 must be fabricated from a material that is safe for use in vivo and allows for visualization in imaging techniques.

[0063] In an exemplary embodiment, the core 4 of the device 1 for measuring and recording compressive force is rigid and made of surgical steel conforming to the PN-EN ISO 9626 standard, while the flexible measuring arm 3 is made of a material that allows it to bend under the influence of contraction without interfering with the natural function of the left ventricle and to return to a resting position during diastole of the left ventricle, and the measuring arm 3 is made of a material that allows the device 1 to be observed using imaging techniques such as X-ray or ultrasound to enable precise insertion and positioning into the left ventricle, and / or includes at least one visualization tag, i.e., a tag. More specifically, in one embodiment, the arm 3 is made of Nitinol tape (Ni-Ti alloy, Kellog's Lab Research, USA). The sleeve 8 that secures the arm 3 and the sleeve 7 that secures the guide 6 are made of any plastic, medically acceptable alloy, such as silver. The stabilizer 5 is made of the same Nitinol tape as the arm 3. Furthermore, both wires of guide 6 are made of surgical hydrophilic wire, with the guide wire having a diameter of 0.90 mm and the stabilizing wire having a diameter of 0.48 to 0.90 mm.

[0064] As described above, the folded device 1 is introduced into the body, for example, inside a transport catheter up to 6 mm in size, and is introduced through the carotid artery. In the folded form, the device 1 has all arms 3 adjacent to the stabilization system 2, and as the catheter retracts, the arms 3 unfold to their target positions, i.e., as shown in Figures 1a and 1b. During the measurement and recording of ventricular compression force, the device 1 is positioned in the left ventricle at the target position, and a wire extending from the top of the core 4 is guided through the carotid artery to the outside of the patient, to the microcontroller and receiving / recording station. After the measurement is complete, the arms 3 and elements of the stabilization system 2 are folded and housed inside the catheter pushed over them, and then the device 1 is removed from the ventricle.

[0065] Device 1, installed in the left ventricle, can be used to determine the value of the compressive force generated by the wall of this ventricle during contraction. The strain gauges 9, installed on a flexible measuring arm 3 and attached by adhesive, deform in exactly the same way and to the same degree as the arm 3 to which they are attached, so that device 1 according to the present invention can measure even the smallest change in resistance, which is then recorded by a recording station, which allows for the determination of the deformation of the arm 3, the determination of the compressive force acting on the ventricle, and subsequently monitoring of cardiac function.

[0066] According to the present invention, a computer implementation method is provided for measuring and recording compressive force measured using device 1, in which, when there is no compressive force, each strain gauge sensor 9 remains in a resting position and its measurement system shows a voltmeter value of 0, on the other hand, when there is a compressive force, each strain gauge sensor 9 is deformed, changing its length as shown in Figure 4b, and the resistance value of the strain gauge changes under the influence of the deformation, which causes the measurement system of a given sensor 9 to show a voltmeter value other than 0, where this value is proportional to the resistance R of the sensor 9, which, as described above, makes it possible to determine the compressive force applied by a specific region of the ventricular wall in contact with the device's measuring arm during cardiac systole and diastole by converting the recorded voltage into a value of compressive force according to the formula F=(ε*E) / S. In the present invention, each flexible measuring arm 3 shows a single point value of the compressive force applied to its interior by the ventricular wall.

[0067] During the operation of device 1, all signals of voltage changes resulting from the deformation of arm 3 (various values ​​of the voltmeter reading) are collected from strain gauge 9 of device 1, appropriately amplified by a voltage amplifier integrated with an analog-to-digital converter, and then, after amplification and processing, sent to a microcontroller where the signals are recorded. Upon completion, the signals are sent from this microcontroller via an asynchronous serial link to an external device, i.e., any suitable device intended to acquire, store, and visualize data, such as a microcomputer with a LINUX® operating system. This microcomputer includes a computer implementation program dedicated to reading data collected from device 1, enabling measurement and recording of compressive force, further visualization of the collected measurements, and monitoring of heart rate. These measurements, after appropriate processing, are presented in the form of graphical courses of changes as a function of time, and then presented as compressive force values ​​using the above formula. The measurements can also be stored on this external hardware. The digital values ​​of the graph can also be stored in a spreadsheet-readable table for more accurate analysis.

[0068] The embodiments described above are given herein only as non-limiting examples of the present invention and in no way limit the scope of protection as defined by the claims. It should be understood that any technical solutions used in the devices and / or methods according to the present invention may be implemented using equivalent techniques without exceeding the scope of protection. The terms proximal, distal, upper, and lower are for clarification purposes only to facilitate understanding of the spatial arrangement of the present invention and in no way limit the scope of protection as described in the claims.

Claims

1. A device (1) for measuring and recording the compressive force applied by the inner surface of the ventricular wall, wherein the device (1) comprises a stabilization system (2) from which at least one flexible measuring arm (3) extends, the proximal end of the flexible measuring arm (3) is connected to the stabilization system (2), and the distal end abuts against the endocardium of the left ventricular wall, A device (1) for measuring and recording ventricular compressive force, characterized in that the device (1) has a spatial structure that fits inside the left ventricle and enables multi-point contact with the endocardial surface, the flexible measuring arm (3) deforms with the contraction and expansion of the left ventricle, and the flexible measuring arm (3) is provided with a sensor (9) for measuring the deformation of the flexible measuring arm (3) that reflects the compressive force of the heart wall on the inside of the left ventricle.

2. The device (1) for measuring and recording ventricular compression force according to claim 1, characterized in that the device comprises a stabilization system (2) for maintaining a stable position of the device within the left ventricle, the stabilization system (2) comprising a stabilizer (5) and a core (4) extending centrally along the long axis of the left ventricle, with one end located at the apex of the heart and the other end in the region of the aortic valve.

3. The device (1) for measuring and recording ventricular compression force according to claim 1 or 2, characterized in that the sensor (9) is a strain gauge sensor.

4. A device (1) for measuring and recording ventricular compressive force according to any one of claims 1 to 3, characterized in that the flexible measuring arm (3), attached to the core (4) of the stabilization system (2), is arranged radially with respect to the long axis of the left ventricle at at least two levels at equal angular intervals from each other, and the length of the flexible measuring arm (3) is adjusted to match the levels to ensure attachment to the periapical and central segments of the left ventricle.

5. A device (1) for measuring and recording ventricular compression force according to any one of claims 1 to 4, characterized in that the contact point where the flexible measuring arm (3) contacts the endocardium is non-traumatic, ensuring deformation of the flexible measuring arm (3) during contraction, while simultaneously eliminating the risk of damaging the endocardium.

6. A device (1) for measuring and recording ventricular compression force according to any one of claims 1 to 5, characterized in that the flexible measuring arm (3) terminates with one of a loop, a ball, or a spherical mesh.

7. A device (1) for measuring and recording ventricular compression force according to any one of claims 1 to 6, characterized in that the sensor (9) installed on the flexible measuring arm (3) is located as close as possible to the proximal end of the flexible measuring arm (3).

8. A device (1) for measuring and recording ventricular compressive force according to any one of claims 1 to 7, characterized in that the flexible measuring arm (3) is made of a material that allows it to bend under the influence of contraction without interfering with the natural function of the left ventricle and to return to a resting position during diastole of the left ventricle, the flexible measuring arm (3) is made of a material that allows it to be visualized, and / or comprises at least one tag that allows it to be visualized.

9. A device (1) for measuring and recording ventricular compression force according to any one of claims 1 to 8, characterized in that each flexible measuring arm (3) has dimensions that allow a sensor (9) to be mounted thereon.

10. A device (1) for measuring and recording ventricular compression force according to any one of claims 1 to 9, wherein the stabilization system (2) further comprises a stabilization guide (6) which terminates at a curved portion at the apex of the heart, preferably the curved portion terminating the stabilization guide (6) is J-shaped, and the stabilizer (5) of the stabilization system (2) is an O-shaped loop.

11. A device (1) for measuring and recording ventricular compression force according to any one of claims 1 to 10, characterized in that the sensor (9) is connected to a resistor system for the sensor that forms a Wheatstone bridge, the Wheatstone bridge, together with a voltmeter, forms a measurement system that generates an electrical signal corresponding to the bending force of the flexible measuring arm (3), the measurement system is connected to a microcontroller, and the data collected by the sensor (9) is transmitted to the microcontroller.

12. A device (1) for measuring and recording ventricular compression force according to any one of claims 1 to 11, characterized in that elements for transmitting measurement signals from individual measurement systems to a microcontroller are installed along a core (4) located in the center of the long axis of the left ventricle.

13. The device (1) for measuring and recording ventricular compression force according to claim 11 or 12, characterized in that the microcontroller has a number of active channels that enable simultaneous acquisition of signals from all measurement systems of the device (1), and receives at least one additional auxiliary signal from other diagnostic equipment.

14. A device (1) for measuring and recording ventricular compressive force according to any one of claims 1 to 13, characterized in that each flexible measuring arm (3) indicates a single point value of the compressive force acting on the inner surface of the left ventricular wall.

15. A device (1) for measuring and recording ventricular compression force according to any one of claims 1 to 14, characterized in that the flexible measuring arm (3) and the elements of the stabilization system (2) are folded and housed in a catheter inserted into the heart, the flexible measuring arm (3) and the elements of the stabilization system (2) take a measurement position after the catheter slides off from the elements of the flexible measuring arm (3) and the stabilization system (2) in the left ventricle, the distal end of the flexible measuring arm (3) then contacts the endocardium of the left ventricular wall, and after the measurement is completed, the flexible measuring arm (3) and the elements of the stabilization system (2) are folded, the catheter slides over them so that the flexible measuring arm (3) and the elements of the stabilization system (2) are housed in the catheter, and the catheter is then removed from the left ventricle to the outside together with the catheter.

16. A computer-implemented method for measuring and recording ventricular compression force by measuring the compression force using a device for measuring and recording ventricular compression force according to any one of claims 1 to 15, wherein, when there is no compression force, the sensor remains in a resting position and the measurement system shows a voltmeter value of 0, and when there is compression force, the sensor deforms and the measurement system shows a voltmeter value other than 0, wherein this value is proportional to the resistance R of the sensor, which makes it possible to determine the compression force exerted by a specific region of the ventricular wall that the flexible measuring arm of the device contacts during contraction and expansion by converting the recorded voltage into a value of the compression force.

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