Improved estimation of catheter to tissue proximity using contact force sensing

Abstract

The name of the invention of the present disclosure is improved estimation of catheter to tissue proximity using contact force sensing. A method for obtaining a tissue proximity indication includes inserting a shaft of a catheter into a body part of a living subject, the catheter including an expandable distal end assembly coupled to a distal end of the shaft, the expandable distal end assembly having a plurality of electrodes disposed thereon. An impedance between each of the electrodes and a reference electrode is measured. Based on the measured impedance, a subset of the electrodes in physical contact with tissue of the body part is identified. A signal is received from a coil assembly coupled at at least one of the distal end assembly and the distal end of the shaft. A total contact force exerted by the assembly on the tissue is estimated based on the signal. Based on the identified subset of the electrodes and the estimated total contact force, one or more masses of the physical contact between the respective electrode and the tissue are inferred. One or more of the inferred qualities of the physical contact are output.

Description

Technical Field

[0001] The present disclosure relates generally to invasive medical probes, and in particular to estimation of catheter-to-tissue proximity. Background Art

[0002] Techniques for estimating the proximity of an electrode of a catheter to tissue have been previously proposed in the patent literature. For example, U.S. Patent Application Publication 2022 / 0183748 describes a method for obtaining a tissue proximity indication, the method comprising inserting a catheter into a body part of a living subject so that the electrode of the catheter contacts the tissue at a corresponding position within the body part. A signal provided by the electrode is received. The method also includes selectively rewarding and punishing a reinforcement learning agent within a reinforcement learning exploration phase to learn at least one tissue proximity strategy in response to at least one of the received signals. The method further includes applying a reinforcement learning agent in a reinforcement learning utilization phase to obtain a corresponding tissue proximity action to be taken in response to at least one tissue proximity strategy, the corresponding tissue proximity action maximizing the corresponding expected reward. The method also includes providing a corresponding derived tissue proximity indication of the proximity of a given electrode in the electrode to the tissue in response to the corresponding tissue proximity action obtained.

[0003] The present disclosure will be more fully understood through the following detailed description of examples of the present disclosure in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figure 1 is a schematic illustration of a catheter-based electroanatomical (EA) mapping and ablation system according to an example of the present disclosure;

[0005] Figure 2 is a schematic illustration of a basket assembly configured to electrically sense tissue proximity and magnetically obtain an indication of contact force according to an example of the present disclosure;

[0006] Figure 3 is a flowchart according to an example of the present disclosure, which schematically illustrates Figure 2 A method for inferring electrode touch quality using a basket cage.

[0007] Figure 4 is a schematic diagram of an example according to the present disclosure, the schematic diagram using estimated contact force to statistically infer touch quality level of an electrode; and

[0008] Figure 5 is a schematic diagram of an example according to the present disclosure, which schematically illustrates a method of inferring the touch quality of component electrodes to tissue. DETAILED DESCRIPTION

[0009] Overview

[0010] The wall tissue of a cavity of an organ of a patient, such as a heart cavity, can be mapped and / or ablated using a catheter having a plurality of electrodes mounted at an expandable distal end assembly of the catheter. In a mapping and / or ablation procedure of a heart cavity, a physician expands the assembly and manipulates the expanded distal end assembly for contacting the electrodes with the cavity wall to acquire or apply an electrical signal.

[0011] The quality of electrical mapping and / or ablation depends on the quality of the physical contact of the electrode with the wall tissue (also referred to in this disclosure as "touch quality (TQ)"). The quality scale can use arbitrary units (e.g., a number from 0 to 10) or can be given in physical units of contact force (e.g., from 0 dynes to 10 dynes, with 1 dyne (= 1 gram·cm·second)). -2 ) is the step length).

[0012] One way to estimate the contact force of the entire assembly (e.g., not a specific electrode) with the tissue is to use a local transmitter-receiver pattern of proximal and distal electromagnetic coils (EMCs), where the distal EMC is set on the distal portion of the expandable assembly and the proximal EMC is set on the distal end of the shaft of the catheter. This local transmitter-receiver pattern produces an accurate estimate of the assembly deflection, namely Δl in 3D relative to the distal end of the catheter shaft. In one example, the technology uses 3 coils distributed on the distal end of the assembly in 3 different XYZ orientations (e.g., in the case of an expandable basket assembly, on 3 different splines), which enables sensing of the 3D position and orientation of the assembly (e.g., of the basket assembly of the catheter) relative to the distal end of the catheter shaft. Using the deflection Δl (e.g., the change in 3D orientation) together with the known spring constant of the distal end assembly (elastic retainer), the processor can use the spring equation (F=K·Δl) to calculate the contact force. The spring constant is known from an elastic model of the holder or based on a laboratory calibration between a known applied force on the holder and a corresponding measured holder deflection (e.g., for measuring the spring constant). A detailed description of a contact force estimation method for a multi-electrode catheter using a position sensor in a local transceiver mode is given in U.S. patent application 18 / 373,308, entitled “Estimation of Contact Force of Catheter Expandable Assembly,” filed on September 27, 2023, which is assigned to the assignee of the present patent application.

[0013] The electrical impedance of the catheter's electrodes is considered an electrode-specific measure of the electrode's proximity to the wall tissue. Since the impedance range encountered by the electrodes is patient and procedure specific, the disclosed algorithm is used to continuously monitor each electrode impedance and look for changes. The impedance measurement can be normalized by detecting the lowest and highest values ​​recorded over time. Lower impedances are typically measured for electrode depressions within the blood pool of the heart chamber, and higher impedances occur when the electrode is in close proximity or physical contact with the tissue (e.g., above 1 dyne).

[0014] For example, touch proximity (TP) can be estimated in this manner by measuring the electrical impedance between electrodes disposed on the distal assembly and body tissue and patch electrodes. Examples of such electrical techniques are further described in U.S. Patent Application Publication 2022 / 0401032. TPI can also be measured more locally between electrodes disposed on the distal assembly and a reference electrode at the distal end of the shaft or on the distal assembly.

[0015] Examples of the present disclosure described herein provide a technique in which a processor infers the real-time quality of physical contact between an electrode and tissue based on measured impedance associated with the contact force applied to the distal tip assembly. The technique achieves an improved estimate of touch quality by determining the relationship between the contact force applied to the tissue by the distal tip assembly as a whole and the impedance measured by the electrode. Although only the contact force of the entire assembly is measured, the relationship applies to any electrode.

[0016] To achieve this relationship, a processor running the disclosed technology identifies a subset of the component's electrodes that are indicated to be in physical contact with the tissue wall by: (i) identifying areas on the surface of the component that are in contact with the tissue (e.g., on an approximate sphere in the case of a basket-shaped component), meaning areas centered primarily in a direction orthogonal to the deflection direction of the component (e.g., Figure 2 as shown), and (ii) considering only electrodes in the region that have sufficient impedance to indicate that they are in sufficiently firm contact with the tissue (e.g., electrodes that have an impedance above a given threshold).

[0017] The processor will Figure 2 The analytical model described in is applied to a subset of the identified electrodes to obtain the relationship between the measured impedance of any electrode and the potential contact force of the electrode with the tissue.

[0018] Thus, during a clinical procedure such as ablation, the processor can estimate in real time the contact force of each electrode of the extendable distal tip assembly based on the measured impedance and the detected force applied to the distal tip assembly to determine, for example, whether electrode TQ is sufficient to apply ablation energy.

[0019] In another example, the processor may use Bayesian estimation (described in Figure 3The TQ of each electrode is statistically inferred using a method (e.g., in terms of contact force) to estimate the most likely touch quality value on a given electrode. The indicated contact force is the input, and the most likely touch quality (e.g., in terms of contact force) is the output of the inference. The Bayesian estimate can change the initial (electrical-only) estimate of the most likely contact force, such as Figure 3 As described in.

[0020] Yet another way to statistically infer the quality of the physical contact is to use a neural network trained using the electrical signals and the respectively estimated contact forces, or directly by using the acquired magnetic position data for training.

[0021] System Description

[0022] Figure 1 is a schematic illustration of a catheter-based electroanatomical (EA) mapping and ablation system 10 according to an example of the present disclosure.

[0023] The system 10 includes one or more catheters that are inserted into a cavity or vascular structure of the heart 12 through the patient's vascular system via the skin by a physician 24. Typically, a delivery sheath catheter is inserted into the left atrium or right atrium near a desired location in the heart 12. One or more catheters may then be inserted into the delivery sheath catheter in sequence to reach the desired location. The one or more catheters may include a catheter dedicated to sensing intracardiac electrogram (IEGM) signals, a catheter dedicated to ablation, and / or a catheter dedicated to both sensing and ablation. An example basket catheter 14 configured for sensing IEGM is illustrated herein. As another example, the catheter 14 may be a tip catheter for ablation and sensing, which is equipped with a contact force mechanism described in U.S. Patent 8,535,308, which is assigned to the assignee of the present application.

[0024] As shown in inset 45, the physician 24 brings the basket assembly 28 (hereinafter also referred to as the "expandable distal tip assembly 28") mounted on the shaft 44 of the catheter 14 into contact with the heart wall to sense a target site in the heart 12. For ablation, the physician 24 similarly brings the distal tip of the ablation catheter to the target site for ablation.

[0025] As shown in inset 65, the basket catheter 14 is an exemplary catheter including one and preferably multiple electrodes 26, which are optionally distributed on multiple splines 22 at an expandable distal tip assembly 28 and are configured to ablate and / or sense IEGM signals. The catheter 14 additionally includes (i) a proximal position sensor 29 (e.g., a dual-axis sensor (DAS) 29 having two orthogonal ECMs or a tri-axis sensor (TAS) including three orthogonal ECMs) embedded in the distal end 46 of the shaft 44 near the basket assembly 28, and (ii) three distal end position sensors 39 (e.g., a single-axis sensor (SAS) 39 including a single EMC) for tracking the position of the distal end of the basket assembly 28. Optionally and preferably, the position sensors 29 and 39 are magnetic-based position sensors that include magnetic coils for sensing three-dimensional (3D) position. An exemplary reference electrode 31 located at the base of the assembly 28 is also shown.

[0026] Down Figure 2 It is shown how the EMC of the distal sensor 39 and the proximal sensor 29 are used in a transmitter-receiver mode to estimate the contact force of the elastic basket-shaped cage with the tissue. At the same time, the impedance signal between the electrodes 26 (bipolar signal) and / or the impedance signal between the electrode 26 and the electrode patch 38 (monopolar signal) is used to electrically estimate the tissue proximity.

[0027] like Figure 2 and Figure 3 As described in, the disclosed technology is based on Figure 2 The model described in quantifies the quality of contact (ie, TP) of each of the plurality of electrodes 26 with the tissue wall using impedance detection associated with contact force detection.

[0028] The magnetic position sensors (29, 39) (i.e., coil assemblies) may also operate in conjunction with an external positioning pad 25 that includes a plurality of magnetic coils 32 configured to generate a magnetic field in a predetermined workspace. To prevent confusion between signals, the frequencies of these fields are different from any given frequency used in the local transmitter-receiver mode for contact force detection. The real-time orientation of the basket assembly 28 of the catheter 14 can be calculated in this manner from the tracked positions of the sensors 29 and 39 (the positions are tracked using magnetic fields generated by the positioning pad 25 and sensed by the magnetic-based position sensors 29 and 39). The relative orientation is represented by the angle formed between the distal end 46 and the longitudinal axis 42 of the expandable assembly 28 (to the distal edge 16 of the assembly).

[0029] Details of magnetic-based position sensing technology are described in U.S. Patents 5,5391,199, 5,443,489, 5,558,091, 6,172,499, 6,239,724, 6,332,089, 6,484,118, 6,618,612, 6,690,963, 6,788,967, and 6,892,091.

[0030] The system 10 includes one or more electrode patches 38 positioned in contact with the skin of the patient 23 to establish a position reference for impedance-based tracking of the positioning pad 25 and the electrodes 26. For impedance-based tracking, current is directed toward the electrodes 26 and sensed at the electrode skin patches 38 so that the position of each electrode can be triangulated via the electrode patches 38. Details of impedance-based position tracking techniques are described in U.S. Patents Nos. 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182.

[0031] Recorder 11 displays electrograms 21 captured using surface ECG electrodes 18 and intracardiac electrograms (IEGMs) captured using electrodes 26 of catheter 14. Recorder 11 may include pacing capabilities for pacing the cardiac rhythm and / or may be electrically connected to a separate pacemaker.

[0032] The system 10 may include an ablation energy generator 50 adapted to conduct ablation energy to one or more electrodes at the distal tip of a catheter configured for ablation. The energy generated by the ablation energy generator 50 may include, but is not limited to, radio frequency (RF) energy or pulsed field ablation (PFA) energy (including monopolar or bipolar high voltage DC pulses that may be used to achieve irreversible electroporation (IRE)), or a combination thereof.

[0033] The patient interface unit (PIU) 30 is configured to establish electrical communication between catheters, electrophysiology equipment, a power source, and a workstation 55 for controlling the operation of the system 10. The electrophysiology equipment of the system 10 may include, for example, a plurality of catheters, a positioning pad 25, surface ECG electrodes 18, electrode patches 38, an ablation energy generator 50, and a recorder 11. Optionally and preferably, the PIU 30 additionally includes processing capabilities for enabling real-time calculations of catheter positions and for performing ECG calculations.

[0034] The workstation 55 includes a memory 57, a processor unit 56 having memory or storage loaded with appropriate operating software, and user interface capabilities. The workstation 55 can provide multiple functions, optionally including: (i) three-dimensional (3D) modeling of the endocardial anatomy and rendering the model or anatomical map 20 for display on the display device 27; (ii) displaying the activation sequence (or other data) compiled from the recorded electrograms 21 on the display device 27 as representative visual markers or images superimposed on the rendered anatomical map 20; (iii) displaying the real-time position and orientation of multiple catheters within the cardiac chamber; and (iv) displaying areas of interest (such as where ablation energy has been applied) on the display device 27. A commercial product embodying elements of the system 10, the commercial product being capable of being displayed in a CARTO TM The 3 system was purchased from Biosense Webster, Inc., 31A Technology Drive, Irvine, CA 92618.

[0035] Although Figure 1 A basket assembly is described, but the figures and disclosed methods apply mutatis mutandis to multi-ray assemblies and balloon assemblies.

[0036] Estimation of touch quality (TQ) of electrodes of scalable components

[0037] Figure 2 is a schematic illustration of a catheter expandable distal tip assembly 28 in contact with tissue 47 according to an example of the present disclosure.

[0038] As shown, the expandable distal tip assembly 28 forms an angle θ308 relative to the distal end 46 of the shaft 44. Angle 308 is defined between the longitudinal axis 307 of the expandable distal tip assembly and the longitudinal axis 305 of the distal end 46. Using the EMC 39, the EMC of the TAS 29, and the known relationship between the distal edge 309 of the assembly and the distal end 46, the processor can easily calculate the angle θ308. The processor can calculate the amount of deflection Δl of the distal edge 309 based on the tilt angle and the length of the expandable distal tip assembly (e.g., length 241). Using the deflection Δl (e.g., change in 3D orientation) together with the known spring constant of the distal tip assembly (elastic retainer), the processor can use the spring equation (F=K·Δl) to calculate the contact force.

[0039] The processor calculates a direction 312 in space pointing away from the region of tissue contact (orthogonal to the direction of the longitudinal axis 307). The electrodes 314, e in this region are identified. 1 、e 2 ,……e k , which gives a corresponding impedance reading z above a threshold value (e.g., 200 ohms) 1 、z2 , ... k Based on the known magnitude and direction of the contact force and the identified electrodes having corresponding impedance readings above a threshold, the force distribution on the identified electrodes may be determined.

[0040] The impedance reading can be between any electrode 314 and the electrode patch 38 (monopolar signal) (the patch is used as a reference), or between any electrode 314 and the reference electrode 31 on the distal tip assembly. Typically, a threshold impedance is determined for each patient during the procedure (e.g., by detecting the lowest and highest impedance values ​​recorded over time).

[0041] The processor can relate the impedance to the contact force by considering the total impedance, To express the total contact force measured, assume that the contact result of a subset of electrodes is, That is, applied to the tissue by a subset of electrodes with some correlation factor, c, Z T =cf T When, for example, a total impedance of 900 ohms is measured at a total contact force of 30 dynes, a typical value for c may be 30 dynes. Given any electrode impedance, its contact force may be estimated by dividing its impedance by the factor c. For example, the estimated contact force for a 100 ohm electrode is 0.3 dynes, indicating that the electrode is in a blood pool. On the other hand, the estimated contact force for a 240 ohm electrode is 8 dynes, indicating that the electrode has a good TQ with the tissue and can therefore be used for ablation.

[0042] Method for estimating touch quality (TQ) of electrodes of a scalable component

[0043] Figure 3 is a flowchart according to an example of the present disclosure, which schematically illustrates Figure 2 A method for inferring electrode touch quality using a basket holder 28 of the present invention. The method includes two phases: an impedance-to-force correlation phase 300 at the beginning of a clinical procedure for identifying a threshold impedance for providing a touch indication and a subsequent TQ estimation phase 320. The impedance-to-force correlation phase can be repeated during the clinical procedure.

[0044] According to the example presented, the algorithm executes the process beginning at a basket assembly insertion step 302 where the physician 24 inserts the expandable distal tip assembly into a cavity (eg, a heart chamber).

[0045] Next, impedance values ​​are sampled and a range of impedance detected for the patient is determined.

[0046] At an impedance thresholding step 306 , processor 56 defines a threshold impedance for a touch indication based on the impedance.

[0047] In stage 320, at an assembly contacting step 317, the physician brings the basket assembly into contact with the patient's lumen wall tissue (eg, tissue 47), for example, to ablate the tissue.

[0048] At an impedance measurement step 319, the processor measures the impedance of the electrodes of the basket assembly.

[0049] At an electrical estimation of touch quality step 321 , processor 56 estimates the touch quality (eg, contact force) of an electrode (eg, electrode 26 ) based on the electrical impedance signal.

[0050] Finally, the processor outputs the inferred electrode touch quality at an output step 323. This information may be displayed to a physician and / or used by another algorithm, such as an EA mapping algorithm or an ablation algorithm.

[0051] Figure 3 The flowchart shown is selected entirely for conceptual clarity. In order to provide a more simplified flowchart, other possible steps (such as, for example, Figure 5 Graphical encoding of TQ as performed in ).

[0052] Statistically inferring electrode touch quality

[0053] use Figure 2 The inference method described is largely analytical. A statistical way to infer the touch quality of an electrode from impedance is to use a prior estimate of the contact force in a Bayesian estimation method. The Bayesian estimation evaluates the most likely value of the contact force on a given electrode. The estimated contact force is the input, in the form of a statistical distribution with the most likely value, and the touch quality is the inferred output.

[0054] Figure 4 is a diagram 400 of touch quality levels of electrodes statistically inferred using estimated contact forces according to an example of the present disclosure. Figure 4 The probability distribution of touch quality for two different electrodes e1 and e2 (such as two electrodes in electrode 26) is shown. As shown, the disclosed technology obtains the probability of touch quality given the measured touch force. For electrode e1, the most likely touch quality is a value 403 above a given threshold 405 (e.g., above 1 dyne). For electrode e2, the most likely touch quality is a value 407 below the threshold 405.

[0055] exist Figure 4, the most likely previous touch quality 413 and 417 estimates for electrodes e1 and e2 are based solely on electrical impedance. As shown, the electrical impedance produces very similar values ​​413 and 417, where both electrodes are considered to have adequate touch quality. As shown, the processor using the disclosed technique updates the touch quality of electrode e2 to be at an insufficient level 407. In contrast, the previous electrical estimate derived level 417 is shown as being greater than the threshold 405.

[0056] Method for estimating contact forces of splines of expandable components of catheters

[0057] Figure 5 is a schematic diagram of an example according to the present disclosure that schematically illustrates a method of inferring the touch quality of an assembly electrode with tissue. According to the example presented, the algorithm executes a process beginning at a basket assembly insertion step 502 by a physician 24 inserting an expandable distal tip assembly into a cavity (e.g., a heart chamber).

[0058] Next, at an assembly contacting step 504, the physician contacts the basket assembly with cavity wall tissue (eg, tissue 47), which causes the basket assembly to change shape or orientation relative to the distal end of the shaft.

[0059] In an electrical estimation of touch quality step 506 , processor 56 estimates the touch quality of an electrode (eg, electrode 26 ) based on the electrical impedance signal.

[0060] In a contact force magnetic estimation step 508 , processor 56 uses the signals from the contact force sensor assembly to estimate the contact force on the basket.

[0061] Using the contact force estimated in step 508 and the impedance determined in step 506 , processor 56 infers the electrode touch quality at an electrode touch quality inference step 510 .

[0062] Finally, the processor outputs the inferred electrode touch quality at an output step 512. This information can be used by another algorithm, such as an EA mapping algorithm or an ablation algorithm.

[0063] Finally, at graphical step 514, the processor graphically indicates the electrodes 26 having a touch quality above a given threshold. This information can be displayed to the physician.

[0064] Figure 5 The flowchart shown is chosen purely for conceptual clarity. Other possible steps (such as imaging the catheter) are intentionally omitted from the disclosure herein in order to provide a more simplified flowchart.

[0065] Example

[0066] Example 1

[0067] A method for obtaining a tissue proximity indication, the method comprising inserting a shaft (44) of a catheter (14) into a body part of a living subject (23), the catheter (14) comprising an expandable distal tip assembly (28) coupled to a distal end (46) of the shaft (44), the assembly (28) having a plurality of electrodes (26) disposed on the distal tip assembly. Impedance between each of the electrodes (26) and a reference electrode (31) is measured. Based on the measured impedance, a subset of the electrodes (26) in physical contact with tissue of the body part is identified. Signals are received from a coil assembly (29, 39) coupled to at least one of the distal tip assembly (28) and the distal end (46) of the shaft. A total contact force applied by the assembly (28) on the tissue is estimated based on the signals. One or more qualities of physical contact between the respective electrodes (26) and the tissue are inferred based on the identified subset of the electrodes (26) and the estimated total contact force. One or more of the inferred masses of physical contact are output (323).

[0068] Example 2

[0069] A method according to embodiment 1, wherein inferring the quality of physical contact includes correlating the impedance with the contact force of each any electrode (26) of the component (28) using the subset of electrodes (26).

[0070] Example 3

[0071] The method of any one of embodiments 1 and 2, wherein outputting the quality of the physical contact comprises providing the quality of the physical contact as a number on a scale.

[0072] Example 4

[0073] A method according to any one of embodiments 1 to 3, and comprising outputting a digital number when the contact force of the corresponding estimated electrode is above a given threshold and the impedance of the electrode (26) is within an estimated impedance range.

[0074] Example 5

[0075] A method according to any one of embodiments 1 to 4, wherein inferring the quality of the quality of physical contact of the electrode (26) includes using Bayesian statistics to derive the probability (403, 407) that the physical contact force is above a given threshold (405) contact force.

[0076] Example 6

[0077] A method according to any one of embodiments 1 to 4, wherein inferring the mass of the mass of physical contact of the electrode (26) includes using a neural network (NN) model to derive a probability of the mass based on the estimated contact force.

[0078] Example 7

[0079] A method according to any one of embodiments 1 to 6, wherein the expandable distal end assembly (28) includes a plurality of splines (22) and one of a plurality of rays, the electrode (26) is disposed on the plurality of splines and one of the plurality of rays, and wherein estimating the contact force includes estimating the contact force applied by one or more of the splines (22) and one of one or more of the rays.

[0080] Example 8

[0081] A method according to any one of embodiments 1 to 7, wherein the expandable distal tip assembly includes a plurality of splines (22) arranged in one of a basket assembly (28) and a multi-ray assembly.

[0082] Example 9

[0083] The method of any one of embodiments 1 to 8, wherein receiving the signal from the coil assembly (29, 39) includes using an electromagnetic coil (EMC) in a local transmitter-receiver layout of the assembly (28).

[0084] Example 10

[0085] A method according to any one of embodiments 1 to 9, wherein measuring impedance includes receiving at least one of a bipolar signal and a monopolar signal acquired by the catheter (14).

[0086] Embodiment 11

[0087] A system (10) for obtaining an indication of tissue proximity includes a catheter (14) and a processor (56). The catheter (14) includes a shaft (44) configured for insertion into a body part of a living subject (23), the catheter also including an expandable distal tip assembly (28) coupled to a distal end (46) of the shaft, the distal tip assembly (28) having a plurality of electrodes (26) disposed thereon. The processor is configured to (i) measure an impedance between each of the electrodes (26) and a reference electrode (31), (ii) identify a subset of the electrodes (26) in physical contact with tissue of the body part based on the measured impedance, (iii) receive signals from a coil assembly (29, 39) coupled to at least one of the distal end assembly (28) and the distal end (46) of the shaft, (iv) estimate a total contact force applied by the assembly (28) on the tissue based on the signals, (v) infer one or more qualities of physical contact between the corresponding electrodes (26) and the tissue based on the identified subset of the electrodes (26) and the estimated total contact force, and (vi) output one or more of the inferred qualities of physical contact.

[0088] Although the examples described herein are primarily directed to cardiac diagnostic applications, the methods and systems described herein can also be used in other medical applications.

[0089] It should be understood that the above examples are cited by way of example, and the present disclosure is not limited to what is specifically shown and described above. On the contrary, the scope of the present disclosure includes combinations and sub-combinations of the various features described above, as well as variations and modifications thereof, which will occur to those skilled in the art upon reading the above description and which are not disclosed in the prior art.

Claims

1. A system for obtaining an indication of tissue proximity, the system comprising: a catheter comprising a shaft configured for insertion into a body part of a living subject, the catheter further comprising an expandable distal tip assembly coupled to a distal end of the shaft, the distal tip assembly having a plurality of electrodes disposed thereon; and A processor, the processor being configured to: measuring impedance between each of the electrodes and a reference electrode; identifying, based on the measured impedance, a subset of the electrodes in physical contact with tissue of the body part; receiving a signal from a coil assembly coupled at least one of the distal tip assembly and the distal end of the shaft; estimating a total contact force exerted by the component on the tissue based on the signal; inferring one or more qualities of physical contact between the corresponding electrodes and the tissue based on the identified subset of the electrodes and the estimated total contact force; as well as One or more of the inferred masses of physical contact are output.

2. The system according to claim 1, wherein: The processor is configured to infer the quality of physical contact by correlating the impedance with a contact force for each any electrode of the assembly using the subset of electrodes.

3. The system according to claim 1, wherein: The processor is configured to output the quality of the physical contact by providing the quality of the physical contact as a number on a scale.

4. The system according to claim 3, wherein: The processor is further configured to output a digital number when the contact force of the corresponding estimated electrode is above a given threshold and the impedance of the electrode is within an estimated impedance range.

5. The system according to claim 1, wherein: The processor is configured to infer a mass of the mass of physical contact of the electrodes by using Bayesian statistics to derive a probability that the physical contact force is above a given threshold contact force.

6. The system according to claim 1, wherein: The processor is configured to infer a mass of the mass of physical contact of the electrode by using a neural network (NN) model to derive a probability of the mass based on the estimated contact force.

7. The system according to claim 1, wherein: The expandable distal tip assembly includes one of a plurality of splines and a plurality of rays, the electrodes are disposed on the plurality of splines and one of the plurality of rays, and wherein the processor is configured to estimate the contact force by estimating the contact force applied by one or more of the splines and one of one or more of the rays.

8. The system according to claim 1, wherein: The expandable distal tip assembly includes a plurality of splines disposed in one of a basket assembly and a multi-ray assembly.

9. The system according to claim 1, wherein: The processor is configured to receive the signal from the coil assembly by using an electromagnetic coil (EMC) in a local transmitter-receiver layout of the assembly.

10. The system according to claim 1, wherein: The processor is configured to measure impedance by receiving at least one of a bipolar signal and a monopolar signal acquired by the catheter.

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