Balloon catheter with force sensor

Abstract

The present invention is entitled "Balloon Catheter with Force Sensor." The present invention provides a system that, in one embodiment, includes a balloon catheter configured to be inserted into a body part of a living subject, the balloon catheter comprising an insertion tube having a distal tip, a force sensor connected to the distal tip, and an inflatable balloon, the inflatable balloon comprising: a proximal portion connected to the force sensor such that the force sensor is disposed between the distal tip of the insertion tube and the inflatable balloon; and a plurality of electrodes disposed about an outer surface of the balloon and configured to contact tissue at corresponding locations in the body part when the balloon is inflated, wherein the force sensor is configured to output at least one force signal indicating a magnitude and direction of a force exerted by the balloon on the tissue when the balloon is inflated.

Description

Technical Field

[0001] The present invention relates to medical devices, and in particular to balloon catheters. Background Art

[0002] Arrhythmias such as atrial fibrillation occur when an area of ​​heart tissue abnormally conducts electrical signals to adjacent tissue, disrupting the normal heartbeat cycle and causing an irregular heartbeat.

[0003] Procedures used to treat cardiac arrhythmias involve surgically disrupting the source of the signals causing the arrhythmia and the pathways used to conduct these signals. By selectively ablating cardiac tissue through the application of energy via a catheter, it is sometimes possible to prevent or alter the propagation of unwanted electrical signals from one part of the heart to another. Ablation methods destroy unwanted electrical pathways by creating non-conductive lesions.

[0004] Verifying that the electrode is in physical contact with the target tissue is important for controlling the delivery of ablation energy. Verifying electrode contact with tissue has been widely attempted in the art, and various techniques have been proposed. For example, U.S. Patent 6,695,808 describes an apparatus for treating a selected area of ​​patient tissue or an organ. A probe has a contact surface that can be abutted against the area, thereby generating a contact pressure. A pressure transducer measures the contact pressure. This arrangement is said to meet the needs of procedures in which a medical device must be securely placed but not in excessive contact with the anatomical surface by providing information to the user of the device indicating the presence and magnitude of the contact force.

[0005] For example, U.S. Patent No. 6,241,724 describes a method for creating ablation lesions in body tissue using a segmented electrode assembly. In one embodiment, the electrode assembly on the catheter carries a pressure transducer that senses contact with tissue and transmits a signal to a pressure contact module. The module identifies the electrode elements associated with the pressure transducer signal and directs the energy generator to deliver RF energy to those elements while avoiding other elements that are in contact only with blood.

[0006] Another example is provided in U.S. Patent 6,915,149. This patent describes a method for mapping the heart using a catheter with a tip electrode for measuring local electrical activity. To avoid artifacts that may be caused by poor contact between the tip and the tissue, a pressure sensor is used to measure the contact pressure between the tip and the tissue to ensure stable contact.

[0007] U.S. Patent Application Publication No. 2007 / 0100332 describes a system and method for assessing electrode-tissue contact for tissue ablation. An electromechanical sensor within a catheter shaft generates an electrical signal corresponding to the amount of electrode movement within the distal portion of the catheter shaft. An output device receives the electrical signal to assess the level of contact between the electrode and tissue.

[0008] Another application of contact pressure measurement is described in US Patent Application Publication No. 2009 / 0093806 to Govari et al., which is incorporated herein by reference, in which a sensor is used to measure deformation in response to pressure on a resilient member at the distal end of a catheter.

[0009] Numerous references have reported methods for determining electrode-tissue contact, including U.S. Patents 5,935,079, 5,891,095, 5,836,990, 5,836,874, 5,673,704, 5,662,108, 5,469,857, 5,447,529, 5,341,807, 5,078,714, and Canadian Patent Application 2,285,342. Several of these references, such as U.S. Patents 5,935,079, 5,836,990, and 5,447,529, determine electrode-tissue contact by measuring the impedance between a tip electrode and a return electrode. As disclosed in the '529 patent, it is well known that impedance through blood is generally lower than impedance through tissue. Therefore, tissue contact is detected by comparing the impedance values ​​between a set of electrodes with previously measured impedance values ​​for electrodes known to be in contact with tissue and electrodes known to be in contact only with blood.

[0010] U.S. Patent 9,168,004 to Gliner et al., which is incorporated herein by reference, describes the use of machine learning to determine catheter electrode contact. The '004 patent describes a cardiac catheterization procedure performed by memorizing the assignment of the contact state between an electrode of a probe and the heart wall as either a contact state or a non-contact state, and making a series of determinations of the impedance phase angle of the current passing through the electrode and another electrode, thereby identifying the maximum and minimum phase angles in the series, and adaptively bounding a binary classifier between the extremes. A test value is compared to the classifier adjusted by a hysteresis factor, and a change in contact state is reported when the test value exceeds or falls below the adjusted classifier.

[0011] U.S. Patent Publication No. 2015 / 0141987 to Caplan et al. describes a device for ablating target tissue in a patient using electrical energy. An elongated shaft includes a proximal portion and a distal portion, with a radially expandable element attached to the distal portion. An ablation element for delivering electrical energy to the target tissue is mounted to the radially expandable element. The device can be constructed and arranged to ablate the patient's duodenal mucosa while avoiding damage to the adventitia. Systems and methods for treating the target tissue are also provided.

[0012] PCT Patent Publication WO 2011 / 139589 to Medtronic Ardian LLC describes catheter devices, systems, and methods for achieving renal neuromodulation via intravascular access. One aspect relates to devices, systems, and methods incorporating a catheter handling device comprising an elongated shaft. The elongated shaft is sized and configured to deliver an energy delivery element to the renal artery via an intravascular route. Thermal or electrical renal neuromodulation can be achieved by directly and / or indirectly applying thermal and / or electrical energy to heat, cool, or otherwise electrically modulate nerve fibers that contribute to renal function or the vascular structures that supply or perfuse the nerve fibers.

[0013] U.S. Patent Publication 2005 / 0203597 to Yamazaki et al. describes a catheter for treating cardiac arrhythmias, comprising a catheter shaft having a double-cylinder structure, wherein an inner shaft is slidably inserted into an outer shaft; a balloon mounted so as to span between the distal ends of the inner shaft and the outer shaft; a pair of high-frequency current-carrying electrodes, at least one of which is disposed within the balloon; and a temperature sensor for monitoring the temperature within the balloon. A leading edge portion of the balloon protrudes from the distal end of the inner shaft, at least in a deflated state. Alternatively, a tube more flexible than the inner shaft is disposed at the distal end of the inner shaft.

[0014] US Patent 4,744,366 to Jang describes a catheter for performing balloon angioplasty that includes concentric independently inflatable / deflated balloons, each having a different diameter.

[0015] U.S. Patent Publication No. 2018 / 0280080 to Govari et al. describes a medical device comprising a probe having a distal end configured for insertion into a body cavity and including a lumen opening through the distal end; and an inflatable balloon capable of being deployed through the lumen into the body cavity such that, when the balloon is deployed through the lumen and inflated, a distal shaft on the distal side of the balloon is positioned relative to the lumen. The medical device also includes an electrode attached to the distal side of the inflatable balloon and extending over at least 50% of an area of ​​the distal side of the balloon within a 30° arc from the distal shaft. Summary of the Invention

[0016] According to one embodiment of the present disclosure, a system is provided, which includes a balloon catheter configured to be inserted into a body part of a living subject, the balloon catheter including an insertion tube having a distal end, a force sensor connected to the distal end, and an inflatable balloon, the inflatable balloon including: a proximal portion connected to the force sensor so that the force sensor is disposed between the distal end of the insertion tube and the inflatable balloon; and a plurality of electrodes disposed around an outer surface of the balloon and configured to contact tissue at corresponding locations in the body part when the balloon is inflated, wherein the force sensor is configured to output at least one force signal indicating the magnitude and direction of the force exerted by the balloon on the tissue when the balloon is inflated.

[0017] Further in accordance with an embodiment of the present disclosure, the system includes a display and processing circuitry configured to calculate a magnitude and direction of the force in response to the at least one force signal, and to present a representation of the force vector and a representation of the inflatable balloon to the display in response to the at least one force signal.

[0018] Further in accordance with one embodiment of the present disclosure, the balloon catheter further comprises at least one position sensor, the at least one position sensor being configured to output at least one position signal indicating a position of the distal tip, the processing circuit being configured to calculate the position of the distal tip in response to the at least one position signal, and to present a representation of the force vector to a display in response to the calculated magnitude and direction, and to present a representation of the inflatable balloon to the display in response to the calculated position and the at least one force signal.

[0019] Additionally, according to one embodiment of the present disclosure, the processing circuit is configured to receive contact signals from the electrodes in response to the contact signals, evaluate a respective quality of contact of each of the electrodes with the tissue, and present a representation of the inflatable balloon to a display while modifying visual features of some of the electrodes in response to the respective quality of contact of the electrodes with the tissue at respective locations.

[0020] Furthermore, according to one embodiment of the present disclosure, each of the electrodes is a flexible electrode formed of a polyamide substrate on which gold is covered.

[0021] According to another embodiment of the present disclosure, an electrophysiological catheter device is provided, which includes: a tubular member extending from a proximal portion to a distal portion along a longitudinal axis; a first connector member connected to the distal portion of the tubular member; a beam connecting member connected to the first connector member, wherein at least one first protrusion is located on one of the beam connecting member and the first connector member, and the first protrusion cooperates with at least one first recess on the other of the beam connecting member and the first connector member; and a second connector member connected to the beam connecting member, wherein at least one second protrusion is located on one of the beam connecting member and the second connector member, and the at least one second protrusion cooperates with at least one second recess on the other of the beam connecting member and the second connector member.

[0022] In further accordance with an embodiment of the present disclosure, the device includes a balloon connected to the second coupler member.

[0023] Further in accordance with an embodiment of the present disclosure, the beam coupling member defines a generally cylindrical surface extending from a first end to a second end, each of the first end and the second end having at least one arm extending along the longitudinal axis, the at least one arm defining a protrusion extending in a circumferential direction about the longitudinal axis.

[0024] In addition, according to one embodiment of the present disclosure, at least one arm at the first end includes three arms extending toward the first connector member, and at least one arm at the second end includes three arms extending toward the second connector member, each arm having a protrusion extending in a circumferential direction around the longitudinal axis.

[0025] Furthermore, according to one embodiment of the present disclosure, the protrusion near the first end is configured to be divided into two slopes extending in a spiral direction along the longitudinal axis toward the other protrusion near the second end.

[0026] Further in accordance with an embodiment of the present disclosure, the first coupler includes a notch configured to mate with a protrusion of at least one arm at a first end, and the second coupler member includes a notch configured to mate with a protrusion of at least one arm at a second end.

[0027] In further accordance with an embodiment of the present disclosure, the device includes a flexible circuit having at least one position sensing coil mounted to one of the first and second coupling members.

[0028] Additionally, according to one embodiment of the present disclosure, the at least one position sensing coil includes two position sensing coils.

[0029] Furthermore, according to one embodiment of the present disclosure, the device includes at least one ablation electrode coupled to the second coupler member and at least one temperature sensor coupled to the second coupler member.

[0030] In further accordance with an embodiment of the present disclosure, the apparatus includes at least one ablation electrode mounted on the balloon and at least one temperature sensor mounted to the balloon.

[0031] Additionally according to an embodiment of the present disclosure, the at least one ablation electrode includes eight ablation electrodes, and the at least one temperature sensor includes eight temperature sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0033] Figure 1 is a diagrammatic representation of a system for assessing electrical activity in the heart of a living subject and providing therapy thereto using a catheter constructed and operative in accordance with an embodiment of the present invention;

[0034] Figure 2 for Figure 1 A schematic diagram of a flexible circuit of a catheter;

[0035] Figure 3 In the folded configuration Figure 2 A schematic diagram of a flexible circuit;

[0036] Figure 4 for Figure 1 A schematic diagram of another flexible circuit of a catheter;

[0037] Figure 5 for Figure 1 A schematic diagram of a beam coupling member 190 of a conduit;

[0038] Figure 6 for Figure 1 a first cross-sectional view of a distal portion of a catheter;

[0039] Figure 7 for Figure 1 a second cross-sectional view of the distal portion of the catheter;

[0040] Figure 8 For the Figure 6 A cross-sectional view taken along line AA;

[0041] Figure 9 is a schematic diagram of a balloon catheter constructed and operative in accordance with an embodiment of the present invention;

[0042] 10A to 10D for Figure 9 Translucent view of the balloon catheter;

[0043] Figure 10E To show Figure 9 A cross-sectional perspective view of components inside the catheter;

[0044] Figure 10F for Figure 10E Exploded views of certain components of the assembly such that when assembled it is aligned with the longitudinal axis LL;

[0045] Figure 10G for Figure 10F A perspective view of a beam coupling member is shown;

[0046] Figure 11 and Figure 12 for Figure 9 Translucent view of the balloon catheter's sensor;

[0047] Figure 13 To include the use Figure 9 Balloon catheter operation Figure 1 a flowchart of the steps in the method of the system; and

[0048] Figure 14 To present Figure 9 Schematic diagram of the balloon catheter and representation of the force vectors. DETAILED DESCRIPTION

[0049] Overview

[0050] Balloon catheters can be inflated to a diameter of about 25 mm or more and are typically used to simultaneously perform ablations on relatively large areas, such as the ostia of the pulmonary veins. On the other hand, focal catheters, which typically have a diameter of about 2.5 mm, are more suitable for performing relatively "pinpoint" ablations in the ventricles. To expand the ablation area, focal catheters can be used for multiple, continuous ablations. Using focal catheters to perform point-by-point ablations is time-consuming, which can be a critical factor when performing cardiac procedures.

[0051] Embodiments of the present invention overcome the aforementioned problems by providing a system comprising a balloon catheter having a diameter of about 15 mm or less when fully inflated. Due to the small size of the balloon, after deflation, the balloon shrinks to a diameter of about 3 mm, without the need for a central extension tube used in many balloon designs to straighten the deflated balloon for reinsertion into the sheath.

[0052] The inflatable balloon can be easily maneuvered around the chambers of the heart to allow ablation of large areas of cardiac tissue to be performed rapidly, thereby reducing ablation time compared to focal catheters.

[0053] The inflatable balloon includes flexible electrodes disposed thereon for sensing electrical signals and / or applying radiofrequency energy to perform ablation. A wire extending from the rear of the electrode can also serve as a temperature sensor for sensing the temperature of the electrode and / or tissue during ablation.

[0054] Maneuverability of an inflated balloon within the heart chambers presents a new challenge: large balloons used to perform ablation in the pulmonary veins occlude the veins due to their large size, and all electrodes around the balloon surface must be in sufficient contact with the vein tissue to provide a good ablation lesion. However, with small balloons, this cannot be guaranteed to be sufficient.

[0055] Embodiments of the present invention overcome the above-mentioned problems by providing a balloon catheter with a force sensor that is disposed between the distal end of the deflectable section of the catheter and the proximal end of the inflatable balloon. The force sensor senses the magnitude and direction of the force applied by the inflatable balloon. In some embodiments, a force vector representing the magnitude and direction of the force can be presented to a display along with a representation of the balloon catheter. An operator of the system can use the force vector to estimate the magnitude and direction of the force applied by the balloon on the cardiac tissue, thereby configuring which electrodes should be used to perform the ablation, at what power, and for how long. In some embodiments, the force vector can indicate the force applied by the cardiac tissue on the balloon.

[0056] In some embodiments of the present invention, the sufficiency of tissue contact between individual electrodes and tissue is used to determine whether to highlight an electrode on a representation of an inflatable balloon presented to a display. The quality of contact can be assessed based on different methods (including using impedance values ​​and / or phase changes in impedance) or based on the amplitude of an intracardiac electrogram (IEGM) signal (by way of example only), as will be described in more detail below. Although contact quality based on impedance or other electrical methods can provide an indication of whether an electrode is in contact with tissue (or at least close to tissue), impedance generally does not provide an accurate picture of the extent of contact. Using contact quality in conjunction with the force vector provides the operator of the system with a more accurate picture of the extent of contact. The operator of the system can then consider both the force vector and the highlighted electrodes to configure which electrodes should be used to perform ablation, at what power, and for how long. For example, the highlighted electrodes can be confirmed by the operator as being in sufficient contact with the tissue based on the direction of the force vector. For another example, if the force vector indicates that the applied force is low, and the direction of the force is consistent with the highlighted electrodes, and the highlighted electrodes indicate that many electrodes are in contact with the tissue, the operator may assume that the catheter is in an area of ​​soft tissue because the catheter may have sunk into the tissue and is partially or completely surrounded by the tissue. The operator may then use this information to set the power and duration of the ablation based on the assumption that the tissue is soft tissue by using a lower power for a shorter time. For another example, if the force vector indicates that the applied force is high, and the direction of the force is consistent with the highlighted electrodes, and the highlighted electrodes indicate that one or two electrodes are in contact with the tissue, the operator may assume that the catheter is in an area of ​​hard tissue (e.g., scar tissue). The operator may then use this information to set the power and duration of the ablation based on the assumption that the tissue is hard tissue by using a higher power for a longer time.

[0057] In response to signals provided by the catheter electrodes (and optionally the body surface electrodes), the processing circuitry can assess the quality of contact between each of the catheter electrodes and tissue in the heart. Any of the catheter electrodes can be in full or partial contact with the tissue of the heart. In some cases, any of the catheter electrodes can be in contact with the tissue via another fluid, such as blood of varying thicknesses. The quality of contact (full or partial contact, or contact via another fluid) between any of the catheter electrodes and the tissue can be assessed based on the signals provided by the catheter.

[0058] The term "contact quality" as used in this specification and claims is defined herein as a quantitative measure of the degree of electrical contact between one of the catheter electrodes and the tissue. "Contact quality" can be expressed directly, for example, as measured electrical impedance, or indirectly, for example, as IEGM amplitude.

[0059] In some embodiments, the catheter can provide a signal that indicates the impedance between the catheter electrode and the body surface electrode. The impedance indication provides an indication of contact quality. Because myocardium is less conductive than blood, a higher impedance value between a catheter electrode and the body surface electrode indicates a higher contact quality between the catheter electrode and the tissue. The impedance value can be selected to define a minimum contact quality that is considered to indicate adequate contact between any of the catheter electrodes and the tissue.

[0060] In some embodiments, the impedance between one of the catheter electrodes and another of the electrodes on the catheter can be used as a measure of contact quality. As disclosed in the '529 patent mentioned in the background section above, impedance through blood is generally lower than impedance through tissue. Therefore, tissue contact can be assessed by comparing the impedance value between a set of electrodes with previously measured impedance values ​​when the electrodes are known to be in full contact with tissue and when the electrodes are known to be in contact only with blood.

[0061] System Description

[0062] Documents incorporated herein by reference are to be considered an integral part of this application, except that, to the extent any term is defined in these incorporated documents in a manner that contradicts a definition explicitly or implicitly set forth in this specification, only the definition in this specification shall prevail.

[0063] Now see Figure 1 , which is a diagrammatic representation of a system 10 for assessing electrical activity in and providing therapy to a heart 12 of a living subject using a catheter 14 constructed and operated in accordance with an embodiment of the present invention. The catheter 14 is inserted percutaneously through the patient's vascular system into a chamber or vascular structure of the heart 12 by an operator 16. The operator 16, typically a physician, brings the distal tip 18 of the catheter into contact with the heart wall, for example, at an ablation target site. The electrical activity map may be prepared according to the methods disclosed in U.S. Patents 6,226,542 and 6,301,496 and in commonly assigned U.S. Patent 6,892,091, the disclosures of which are incorporated herein by reference in their entireties. A commercial product embodying elements of the system 10 may be The 3 system was purchased from Biosense Webster, Inc., 31 Technology Drive, Irvine, CA, 92618.

[0064] Ablation can be performed by applying thermal energy to areas that are determined to be abnormal, for example, by evaluating electrical activity maps, for example, by conducting radiofrequency current through wires in the catheter to one or more electrodes at the distal tip 18, which apply radiofrequency energy to the target tissue. The energy is absorbed in the tissue, heating the tissue to a point where it permanently loses its electrical excitability (typically above 50°C). This procedure creates non-conductive lesions in the heart tissue that interrupt the abnormal electrical pathways that cause the arrhythmia. Such principles can be applied to different chambers of the heart to diagnose and treat a variety of different arrhythmias.

[0065] The catheter 14 typically includes a handle 20 having suitable controls thereon to enable the operator 16 to steer, position, and orient the distal end of the catheter as desired for the ablation procedure. To assist the operator 16, the distal portion 18 of the catheter 14 or a portion thereof may contain a position sensor, such as a trace or coil, that provides a signal to a processor 22 located in a console 24 (as discussed below).

[0066] Ablation energy and electrical signals may be transmitted back and forth between heart 12 and console 24 via cable 38 through one or more ablation electrodes 32 located at or near distal tip 18. Pacing signals and other control signals may be transmitted from console 24 to heart 12 via cable 38 and electrodes 32.

[0067] A wire connector 35 couples the console 24 with the body surface electrodes 30 and other components of a positioning subsystem for measuring the position and orientation coordinates of the catheter 14. The processor 22 or another processor can be an element of the positioning subsystem. The electrodes 32 and the body surface electrodes 30 can be used to measure tissue impedance at the ablation site as set forth in U.S. Patent 7,536,218 to Govari et al., which is incorporated herein by reference in its entirety. A temperature sensor, typically a thermocouple or thermistor, can be mounted on or near each of the electrodes 32. Examples of temperature sensors used in conjunction with ablation electrodes are shown and described in U.S. patent application SN 15 / 939,154, filed on March 28, 2018, a copy of which is incorporated by reference in the appendix to the priority patent application of that patent application.

[0068] The console 24 typically includes one or more ablation power generators 25. The catheter 14 can be adapted to deliver ablative energy to the heart using any known ablation technique, such as radiofrequency energy, ultrasound energy, cryogenic energy, and laser-generated light energy. Such methods are disclosed in commonly assigned U.S. Patents 6,814,733, 6,997,924, and 7,156,816, which are incorporated herein by reference in their entirety.

[0069] The positioning subsystem may also include a magnetic position tracking arrangement that determines the position and orientation of the catheter 14 by generating magnetic fields in a predefined workspace using a magnetic field generator 28 and sensing these fields at the catheter using coils or traces disposed within the catheter (typically near the tip). The positioning subsystem is described in U.S. Patent 7,756,576, which is incorporated herein by reference in its entirety, and in the aforementioned U.S. Patent 7,536,218.

[0070] Operator 16 can observe and adjust the functions of catheter 14 via console 24. Console 24 includes processor 22, which implements processing circuitry including appropriate signal processing circuitry. Processor 22 is coupled to drive display 29. The signal processing circuitry typically receives, amplifies, filters, and digitizes signals from catheter 14, including signals generated by sensors such as electrical sensors, temperature sensors, and contact force sensors, and a plurality of position sensing coils or traces located distal to catheter 14. The digitized signals are received and used by console 24 and the positioning system to calculate the position and orientation of catheter 14 and to analyze electrical signals from electrodes and contact force sensors.

[0071] To generate the electroanatomical map, processor 22 typically includes an electroanatomical map generator, an image registration program, an image or data analysis program, and a graphical user interface configured to present graphical information on display 29 .

[0072] Typically, the system 10 includes other elements that are not shown in the drawings for simplicity. For example, the system 10 may include an electrocardiogram (ECG) monitor that is connected to receive signals from one or more body surface electrodes to provide an ECG synchronization signal to the console 24. The system 10 also typically includes a reference position sensor that is located on an external reference patch attached to the outside of the subject's body or on an internal catheter inserted into the heart 12 and maintained in a fixed position relative to the heart 12. A conventional pump and tubing can be provided for circulating fluid through the catheter 14 to cool the ablation site. The system 10 can receive image data from an external imaging modality such as an MRI unit, CT, etc. and include an image processor that can be incorporated into the processor 22 or called by the processor to generate and display images.

[0073] Figures 2 to 8A force and position sensor for use in the distal tip of a catheter 14 is described. The sensor typically needs to fit within the small inner diameter of the catheter (e.g., typically equal to or less than approximately 2.5 mm), but various design constraints associated therewith can be overcome to reliably provide feedback. For example, a metal coil can be used to detect position within a magnetic field. Generally, larger, thicker coils provide better detection than smaller, thinner coils; however, due to the limited space within the catheter, the coils need to be small and thin enough to fit within it. Additionally, when such coils are fabricated as traces on a circuit board or flexible circuit via a photolithographic process, the process limits the trace pitch. While the thickness of the trace can be photolithographically increased using additional layers, this option can be expensive, and the coils can be damaged as yield decreases nonlinearly with the number of layers. These design challenges consist of including additional structures close to the position traces, such as force sensors, to provide sub-gram force measurements, reducing crosstalk interference that can result from packing structures into a tight space, and facilitating assembly and secure routing.

[0074] Now see Figure 2 , the figure is Figure 1 Schematic diagram of a flexible circuit 110 for a catheter 14. The flexible circuit 110 can be used within a catheter, such as catheter 14, to provide signals indicating position and force to a processor 22 in a console 24. The flexible circuit 110 includes a substantially planar substrate 112 having a first portion 114 having a first shape (e.g., a circular or trilobal shape as shown) formed by three segments 160, 162, and 164. The flexible circuit 110 also includes a second portion 116 having a second shape (e.g., a substantially rectangular shape as shown) formed by two generally rectangular segments connected by a connecting segment 126 and an optional connecting segment 150. The first portion 114 and the second portion 116 are generally different shapes because, as described below, portion 116 is elongated and assembled with its long axis parallel to the longitudinal axis of the catheter 12, while portion 114 is assembled transverse to the longitudinal axis of the catheter 12 so that it is intended to fit within the inner diameter of the catheter 14 (i.e., have a maximum width or diameter that is less than the inner diameter of the catheter 14). The substrate may be formed of any suitable material that is non-conductive and capable of withstanding high temperatures, such as, but not limited to, polyimide, polyamide, or liquid crystal polymer (LCP).

[0075] The substrate 112 may also include additional portions, such as a third portion 130 and a fourth portion 142. Each of these portions may also include various segments. The third portion 130 may have a similar structure to the second portion 116 and may include generally rectangular segments 132, 134 connected via at least one connecting segment (such as 136 and / or 152). The fourth portion 142 may include at least three connecting segments 144, 146, and 148 that connect the fourth portion 142 to the first portion 114, the second portion 116, and the third portion 130, respectively.

[0076] Electronic components may be incorporated into substrate 112 and its various portions and segments. For example, substantially flat coils or traces (i.e., force sensing coils or traces) for measuring force-related signals may be provided on first portion 114. Specifically, coil 118 may be provided on segment 160, coil 170 may be provided on segment 162, and coil 172 may be provided on segment 164. Coils 118, 170, and 172 may be separate from one another, as shown, or they may each be connected to one or both of the other coils. A portion of each coil, or an extension thereof, may extend from the coil to and be soldered to solder points 168 (only some are labeled for simplicity) located on fourth portion 142. If the three coils are separate from one another, each coil should include at least one corresponding wire (e.g., 166, 174, and 176) connected to solder points 168. If the coils are separate from one another, the signals generated in each coil can be used to provide additional force details, such as an indication of the eccentric force or off-axis direction of the force. As shown, each coil on the first portion 114 includes approximately five turns. However, because signal strength is a function of the number of turns, the number of turns can be maximized based on the size of each segment and the pitch achievable by the photolithographic process.

[0077] Planar coils or traces for measuring position-related signals (i.e., position coils or traces) may also be incorporated into second portion 116 and third portion 130. Coil 120 may be disposed on segment 122, coil 128 may be disposed on segment 124, coil 138 may be disposed on segment 132, and coil 140 may be disposed on segment 134. Each of coils 120, 128, 138, 140 may extend to a weld 168 on fourth portion 142. For example, coil 120 may include an extension 154 connected to weld 168 via connecting segment 146, and coil 128 may include an extension 156 connected to weld 168 via connecting segment 126, segment 122, and connecting segment 146. As shown, each coil on portions 116 and 130 includes approximately five turns. However, because signal strength is a function of the number of wire turns, the number of wire turns can be maximized based on the size of segments 122 , 124 , 132 , and 134 and the pitch achievable by the photolithographic process.

[0078] Second portion 116 is laterally disposed to one side of first portion 114 and fourth portion 142, and has third portion 130 laterally disposed to the other side of first portion 114 and fourth portion 142. Thus, fourth portion 142 is disposed between first portion 114, second portion 116, and third portion 130. Additionally, segments 122 and 124 have traces wound in opposite directions.

[0079] Substrate 112 can be a single layer. Alternatively, the substrate can include more layers, for example, but not limited to, between two and ten layers, such as four layers. This allows the coil to be thickened by adding layers. However, as mentioned above, thickening by adding layers results in a non-linear reduction in yield when manufacturing the component. The flexibility of flexible circuit 110 provides a solution to this trade-off, as will be described below.

[0080] Now see Figure 3 , which is in the folded configuration Figure 2 Schematic diagram of flexible circuit 110. By deforming or bending connectors 126 and 150, segment 124 can be folded over the top of segment 122 so that coil 128 is aligned with coil 120. Similarly, by deforming or bending connectors 136 and 152, segment 134 can be folded over the top of segment 132 so that coil 140 is aligned with coil 138. Although connectors 150 and 152 are optional, they can help align the coils with each other by reducing relative rotation between the segments. If substrate 112 is formed from multiple layers, such as four layers, then after folding segment 124 onto segment 122, coils 120 and 128 form a combined coil having more than two layers, such as eight layers. Folding different segments onto each other to create a combined coil allows for the formation of coils having more layers without adversely affecting manufacturing yields.

[0081] An advantage of a thinner substrate (e.g., four layers) over a thicker substrate (e.g., eight layers) is that it is easier to deform or bend, which facilitates assembly of the flexible circuit 110 to other catheter components and ultimately fitting it within the inner diameter of the catheter, as will be described.

[0082] Now see Figure 4 , the figure is Figure 1 FIG2 is a schematic diagram of another flexible circuit 180 of the catheter 14. The flexible circuit 180 includes a substrate 182 and one or more coils 184. The structure of the flexible circuit 180 is similar to the structure of the first section 114 of the flexible circuit 110. However, in various embodiments, the number or pitch of the coils may vary, and the individual coils on the three sections may be separate from or integral with each other.

[0083] Now see Figure 5 , the figure is Figure 1FIG2 is a schematic diagram of a beam coupling member 190 of a catheter 14. The helical beam coupling member 190 includes a top surface 192, a bottom surface 194, and various arms 196 that can be used to connect the beam coupling member 190 to other components of the catheter 14. The beam coupling member 190 has a known or predetermined spring constant that provides a relationship between distance and force according to Hooke's law. The flexible circuit 180, the first portion 114 of the flexible circuit 110, and the helical beam coupling member 190 together form a force sensor subassembly that receives electrical signals from the console 24 and provides electrical signals to the console, which can process the received signals to determine the force, e.g., sub-gram force, applied to the distal end 18 of the catheter 14.

[0084] The first portion 114 of the flexible circuit 110 (including the coils 118, 170, 172) is disposed on the bottom surface 194, and the coil 184 on the flexible circuit 180 is disposed on the top surface 192. In some embodiments, the first portion 114 of the flexible circuit 110 (including the coils 118, 170, 172) is disposed on the top surface 192, and the coil 184 on the flexible circuit 180 is disposed on the bottom surface 194.

[0085] The wires extending between the console 24 and the solder points 168 of the fourth portion 142 of the flexible circuit 110 (at Figure 6 and Figure 7 The console 24 is connected to the coils 118, 170, and 172 on segments 160, 162, and 164 of the first portion 114 via coil extensions 166, 174, and 176, respectively. Wires extending from the console 24 (also within the cable bundle 198) connect to one or more coils 184 on the flexible circuit 180. An electrical signal (e.g., having an RF frequency) from the console 24 can be used to power either the coils 118, 170, 172 on the first portion 114 of the flexible circuit 110 or the coil 184 on the flexible circuit 180. Whichever set of coils receives power from the console 24 can be considered a transmitter (i.e., one of the flexible circuits 110 or 180) because it emits an electromagnetic field that varies depending on the frequency of the signal received from the console 24. The set of coils not powered by the console 24 can be considered a receiver because it acts like an antenna in response to the electromagnetic field from the transmitter. As a result, the receiver (i.e., the other of the flexible circuits 110 or 180) generates an electrical signal that can be transmitted to the console 24 for analysis. The electrical signal generated by the receiver depends on the distance between the receiver and the transmitter, such that the electrical signal generated by the receiver can be correlated with the distance between the receiver and the transmitter, which is correlated with the compressive displacement of the beam coupling member (e.g., approximately 100 nanometers), and therefore, the force against the distal end 18 of the catheter 14, which causes the spring 190 to compress.

[0086] Beam coupling member 190 may deflect more on one side than the other. This eccentric deflection represents the lateral component of the force applied by tip 18. The lateral force may be detected by the different distances between coils 118, 170, 172 and coil 184, which may be calculated, for example, from the signals provided by coils 118, 170, 172.

[0087] In use, the console 24 can process these signals and use them to adjust the amount of ablation energy supplied to the electrodes. For example, when the signal indicates that the beam coupling member 190 is in a relaxed state (i.e., not compressed), this can be interpreted as an indication that the distal end 18 of the catheter 14 is not in contact with the tissue and, therefore, ablation energy should not be supplied to the electrodes. An indication of this information can also be provided to the operator 16 on the display 29 (e.g., in units of force, such as grams-force), so that the operator 16 can manually adjust the ablation settings.

[0088] The top distal side 192 and the bottom proximal side 194 of the beam coupling member 190 can be parallel to each other and oriented transversely to the longitudinal axis of the beam coupling member 190 (e.g., at an angle greater than about sixty degrees and less than or equal to ninety degrees, such as about eighty degrees). Thus, in some embodiments, the receiver and transmitter attached thereto are similarly oriented. The inventors have determined that the transverse, but non-perpendicular, orientation of the receiver and transceiver increases the sensitivity of the receiver because the distance between the transmitter and the receiver is minimized compared to when the receiver and transceiver are arranged perpendicular to the longitudinal axis of the beam coupling member 190 and the longitudinal axis of the catheter.

[0089] Now see Figures 6 to 8 . Figure 6 for Figure 1 A first cross-sectional view of the distal portion of the catheter 14. Figure 7 for Figure 1 A second cross-sectional view of the distal portion of the catheter 14. Figure 8 For the Figure 6 A cross-sectional view taken along line AA. Figure 6 The flexible circuit 110 is shown assembled to the beam coupling member 190 and the coupler or coupling sleeve 200. Although not shown, the first portion 114 of the flexible circuit 110 is adhered to the proximal side 194 ( Figure 5 ), and the flexible circuit 180 is adhered to the distal side 192 of the beam coupling member 190 ( Figure 5 ).exist Figure 7 , the distal end 18 including the ablation electrode 32 and the various irrigation holes 214 is attached to the beam coupling member 190. The cable bundle 198 is also shown. Figure 6 and Figure 7The cable harness 198 includes a set of wires, although not shown, connected to the solder joints 168 on the fourth portion 142 of the flexible circuit 110 and thus to the various coils or traces on the flexible circuit 110 and to the coils or traces 184 on the flexible circuit 180. Figures 6 to 8 As shown, the flexible circuit 110 is no longer planar. Instead, the flexible circuit has been deformed to have a generally circular transverse cross-section. The segment 124 of the second portion 116 is Figure 6 and Figure 7 1. The most visible segment of the flexible circuit 110 in FIG. Segments 122, 132, and 134, as well as various sides of connectors 126, 136, 146, 150, and 152, are also visible in these figures. As shown, these connectors have been deformed into a curved or curved configuration for attachment to the coupler 200. Specifically, segment 122 adheres to the substantially flat surface 202 of the coupler 200, and segment 132 adheres to the substantially flat surface 204 of the coupler 200 ( Figure 8 ). Assembled as such, these portions of the flexible circuit 110 can be considered to have a triangular cross-section. Additionally, the connector 146 is adhered to the circular (or arcuate) surface 206 of the coupler 200, and the connector 148 is adhered to the circular (or arcuate) surface 208 of the coupler 200. Assembled as such, these portions of the flexible circuit 110 can be considered to have a circular (or arcuate) cross-section. The fourth portion 142 can also be adhered to the substantially flat surface 210 of the coupler 200.

[0090] The diameter or width of the circular portion of the cross-section of the flexible circuit 110 assembled to the coupler 200 is equal to or approximately equal to the diameter or maximum width of the first portion 114, which is also equal to or approximately equal to the maximum width (or base) of the triangular portion of the cross-section of the flexible circuit 110 assembled to the sleeve 100. Thus, when assembled, the flexible circuit 110 can be easily inserted into the outer tube or sleeve 216 ( Figure 1 ), the outer tube or sleeve provides the outer surface of the catheter 14 and defines the inner diameter into which the components of the catheter 14 (e.g., the flexible circuit 110, the beam coupling member 190, the coupler 200) fit. To help prevent soft spots beneath the sleeve 216 caused by gaps between the substantially flat outer surfaces of the segments 124 and 134 and the portion 142 on the one hand, and the curvature of the sleeve 216 on the other hand, these gaps can be formed by forming a second portion 116 ( Figure 2 ) and Section III 130( Figure 2) segments 124 and 134 and portion 142 may be filled with additional material such as adhesive 218 and polyimide layer 220. Polyimide layer 220 may be fabricated separately from and adhered to flexible circuit 110, or they may be an integral part of flexible circuit 110 formed during the same photolithography process as the rest of flexible circuit 110. Polyimide layer 220 may be formed as a series of substantially flat steps or a curve within the layer insert sleeve 216.

[0091] The flexible circuit 110 can be assembled into the catheter 14 as follows. First, the flexible circuit 110 can be provided. The segment 124 of the second portion 116 can be folded over the segment 122 of the second portion 116 to overlap and contact therewith by deforming the connector 126 and the connector 150 (if included). The segment 134 of the third portion 130 can be folded over the segment 132 of the third portion 130 to overlap and contact therewith by deforming the connector 136 and the connector 152 (if included). The first portion 114 of the flexible circuit 110 can be oriented parallel to the bottom surface 194 of the beam coupling member 190, which is oriented transversely (e.g., at an angle less than 30 degrees from a vertical plane) to the longitudinal axis of the beam coupling member 190. The first portion 114 can then be adhered to the bottom surface 194 of the beam coupling member 190. A coupler 200 having a substantially flat surface portion can be provided and oriented so that its longitudinal axis is aligned with the longitudinal axis of the beam coupling member 190. 19. The second portion 116 and the third portion 130 can be oriented parallel to respective substantially planar surface portions of the coupler 200. The second portion 116 and the third portion 130 can then be adhered to respective substantially planar surface portions of the coupler 200. The coupler 200, adhered to the flexible circuit 110, can then be coupled or inserted into the outer sleeve 216. Finally, the end 18 can be attached to the beam coupling member 190. The flexible circuit 180 can be adhered to the top surface 192 of the beam coupling member 190 at nearly any step in the process, as long as the end 18 is not already attached to the beam coupling member 190.

[0092] Now see Figure 9 , which is a schematic diagram of a balloon catheter 300 constructed and operative in accordance with an embodiment of the present invention. 10A to 10D , these figures are Figure 9 In all subsequent drawings herein, it should be understood that Figure 5 The beam member 190 can be connected with Figure 10F and Figure 10G The specific variations shown and described are used together.

[0093] Balloon catheter 300 is configured to be inserted into a body part of a living subject, such as a heart chamber or any other suitable body part. Balloon catheter 300 includes an insertion tube 302 having a distal tip 304. Insertion tube 302 can have any suitable outer diameter depending on the body part into which balloon catheter 300 is to be inserted. In some embodiments, the outer diameter of insertion tube 302 is approximately 3 mm.

[0094] Balloon catheter 300 includes an inflatable balloon 306 comprising: a proximal portion 308 connected to the distal end 304 of insertion tube 302 via a force sensor 312; and a plurality of electrodes 310 disposed thereon. Inflatable balloon 306 also includes various irrigation holes 311 (for simplicity, only one irrigation hole is labeled). Inflatable balloon 306 can have any suitable diameter when fully inflated. In some embodiments, inflatable balloon 306 has an outer diameter of less than 15 mm. Electrodes 310 are configured to contact tissue at corresponding locations in a body part. Each electrode 310 is a flexible electrode formed, for example, from a polyamide substrate coated with gold, or any other suitable material combination. Each electrode 310 is connected to the proximal end of insertion tube 302 via a wire (not shown), which can also serve as a temperature sensor to provide a signal indicating the temperature of electrode 310 for use during ablation.

[0095] The balloon catheter 300 includes a force sensor 312 disposed near the distal tip 304 of the insertion tube 302 and configured to output at least one force signal indicating the magnitude and direction of the force applied by the inflatable balloon 306 upon tissue inflating. The force sensor 312 is disposed between the distal tip 304 of the insertion tube 302 and the proximal portion 308 of the inflatable balloon 306.

[0096] Force sensor 312 is connected to insertion tube 302 and inflatable balloon 306 using lower and upper couplers 314, 316, respectively. Lower and upper couplers 314, 316 may use any suitable coupling mechanism, such as, but not limited to, threaded couplings, bayonet couplings, or press-fit couplings.

[0097] The balloon catheter 300 includes at least one position sensor 318 configured to output at least one position signal indicative of the position of the inflatable balloon 306 and / or the distal tip 304. The position sensor 318 is referenced Figure 12 In some embodiments, the electrodes 310 may be used in conjunction with the body surface electrodes 30 ( Figure 1 ) combined with a position sensor, the surface electrode using a current-based or impedance-based position tracking method, or using the above reference Figure 1A combined magnetic and current / impedance based position tracking method is described in more detail.

[0098] Due to the small size of the balloon, after deflation, the balloon shrinks to a diameter of approximately 3 mm, without the need for a central extension tube used in many balloon designs to straighten the deflated balloon for reinsertion into the sheath. The inflatable balloon can be easily maneuvered around the chambers of the heart to allow ablation of large areas of cardiac tissue to be performed quickly, thereby reducing ablation time compared to focal catheters.

[0099] During ablation, RF power can be applied equally to all electrodes 310, or a multi-channel RF generator can be used to selectively apply power to each of the electrodes 310. The power level can be controlled based on temperature feedback or by manually controlling the power. The electrodes 310 can also be used to sense electrical activity in a body part, such as IEGM.

[0100] Figure 10B and Figure 10D The coupler / shunt 330 is shown connected to the distal portion of the force sensor 312. The coupler / shunt 330 is an elongated member ( Figure 10A and Figure 10B ). An irrigation line 334 is disposed in the insertion tube 302 and extends into the central portion of the coupler / shunt 330 and is bonded to a proximal segment of the coupler / shunt 330. The coupler / shunt 330 includes an irrigation port 332 therein through which irrigation fluid enters the inflatable balloon 306 from an opening at the end of the irrigation line 334. A wire 336 connected to the electrode 310 (also serving as a temperature sensor) is fed through the insertion tube 302 and resides outside a proximal elongated opening 338 of the coupler / shunt 330. These openings are then sealed to prevent irrigation fluid from entering the insertion tube 302.

[0101] The inflatable balloon 306 is bonded to the proximal and distal segments of the coupler / shunt 330. At the distal segment of the inflatable balloon 306, a polymer ring 340 secures the inflatable balloon 306 and / or the distal portion of the electrode 310 to the coupler / shunt 330 to prevent delamination of the electrode 310. A partial balloon 342 covers the inflatable balloon 306 and the proximal segment of the inflatable balloon 306 to protect the non-ablative surfaces of the lead 336 and the electrode 310. The partial balloon 342 can be configured to occupy a portion of the hemisphere to ensure that certain components, such as wiring and circuit traces, are protected between the main balloon 306 and the partial balloon 342.

[0102] Figure 10C and Figure 10DA protective sleeve 344 is shown covering the force sensor 312, the x-axis coil 322, the y-axis coil 324, and the pad area 320. The protective sleeve 344 is generally formed of any suitable plastic. A deflectable element 346 (in the form of a traction cable) may be provided in the distal portion of the insertion tube 302 to facilitate deflection of the balloon catheter 300, such as Figure 10D shown.

[0103] Figure 10E A cross-sectional view of an exemplary end effector of the catheter 24 is shown. Beginning at the distal end 304 of the tubular member 302, a first (or lower) coupler 314 is provided that extends along the longitudinal axis LL of the tubular member 302 through a central opening defined by the position sensor coils 322, 324 and the beam coupling member 190 and the contact force coil circuits 110 and 180. The first coupler 314 terminates just before making physical contact with the coil 114 (leaving a small gap between the coupler 314 and the coil 114). The coupler 314 is coupled to the beam coupling member 190, where as shown in FIG. Figure 10F Irrigation fluid (arrows) is delivered along an irrigation line 334 extending through coupler 314, beam coupler 190, and coupler 316 such that the irrigation fluid strikes flat surface 332a to redirect the fluid flow out of port 332 at an angle of approximately 90 degrees or greater.

[0104] See also Figure 10F , the figure is Figure 10E , the coupler 314 is provided with a plurality of notches 314 a , 314 b , 314 c on the periphery of the cylindrical member 314 for corresponding engagement with the protrusions 194 a , 194 b , 194 c of the beam coupling member 190 .

[0105] Second coupler 316 is provided with recesses 316a, 316b, 316c that mate with protrusions 192a, 192b, 192c of beam coupling member 190. Flat surfaces 316d (three shown for coupler 316) are formed, whereby each flat surface 316d is angled relative to axis LL such that each flat surface is complementary to angle 190 (i.e., the helical angle) defined by the helical paths of ramps 193a, 193b, 193c. Three flat surfaces 314d (not shown due to perspective) 314d are also provided for coupler 314 in a configuration similar to flat surfaces 316d of coupler 316, as these three flat surfaces 314d are also angled relative to axis LL such that each flat surface 314d of coupler 314 is substantially parallel to the angled path 190 defined by helical ramps 193a, 193b, 193c and to flat surfaces 316d.

[0106] Position sensor coils 322 and 324 are mounted to the first coupling 314 in a substantially equiangular configuration about the axis LL. It should be noted that while two coils (for the XY axes) are used in the exemplary embodiment to determine the position of these coils (e.g., mounted to the coupling, thereby determining the position of the balloon, since the distance between the balloon and the position sensor is known), in some cases, if the other two axes are known via other visualization techniques, only one position sensing coil may be used. Similarly, depending on the packaging constraints of the catheter, three position sensing coils may also be used.

[0107] Figure 10G The beam coupling member 190 is shown (with other components hidden to better illustrate structural details). The beam coupling member 190 defines a generally cylindrical form factor about the axis LL so that the beam coupling member 190 can be mounted inside the catheter outer tube 344. Three arms 192 extend along the axis LL to Figure 10F At the first (or distal) end of each arm, each arm has a protrusion 192a, 192b, 192c, whereby each protrusion (192a, 192b or 192c) further extends in a circumferential direction relative to the longitudinal axis LL. At the other end, three arms 194 extend along the axis LL to Figure 10F At the second (or proximal) end of the beam coupling member 190, each arm has a protrusion 194a, 194b, 194c, whereby each protrusion (194a, 194b, or 194c) extends further in a circumferential direction relative to the longitudinal axis LL. Note that when the viewer is viewing the beam coupling member 190 proximal to the axis LL, the protrusions 192a, 192b, and 192c extend in a counterclockwise circumferential direction away from each arm 192. This is in contrast to the protrusions 194a, 194b, and 194c (at the other end), which extend in a clockwise circumferential direction away from each arm 194. This opposite orientation feature of the protrusions ensures that once the proximal protrusions (194a, 194b, 194c) of the beam coupling member 190 engage the recesses (314a, 314b, 314c) of the first coupler 314, and the distal protrusions (192a, 192b, 192c) engage the recesses (316a, 316b, 316c) of the second coupler 316, the couplers 314 and 316 remain connected in the catheter (via the respective recesses 314a and 316a).

[0108] Each protrusion 192a, 192b, 192c is constructed as two components, so that it can form an element of a biasing member or spring member. For example, protrusion 192a is divided into spiral ramps 191a and 193a that extend circumferentially relative to and along axis LL. Spirals 191a and 193a define a spiral path around and along axis LL to reconnect at protrusion 194b. Similarly, protrusion 192b at one end (e.g., the distal end) is divided into two spiral ramps 191b and 193b separated by a through gap between the two spiral ramps 191b and 193b, and thus the two ramps 191b and 193b reconnect at protrusion 194c at the other end (e.g., the proximal end). Finally, protrusion 192c is divided into ramps 191c and 193c that spiral around axis LL and reconnect at protrusion 194a (with a through gap between them).

[0109] By forming these helical ramps (with gaps between each ramp), Applicants were able to convert a generally beam-like structure into a hybrid beam-spring coupling with three helical spring windings. In addition to performing the function of a helical spring, this design enables Applicants to: (a) retain flexible circuit 180 between protrusions 192a, 192b, 192c via notch 195; (b) retain flexible circuit 110 between protrusions 194a, 194b, 194c via circumferential notch 195; and (c) maintain couplings 314 and 316 in place; and (d) transfer force from coupling 316 to protrusions 192a, 192b, 192c, and from coupling 314 to protrusions 194a, 194b, 194c, to measure displacement between each of the pancake-shaped pairs of flexible circuits 180 and 110. These features have not been previously provided in the art, except for Applicants' design described herein.

[0110] With this configuration of couplers 314 and 316 and beam coupling member 190, the force applied from balloon 18 to coupler 316 is transferred to beam coupling member 190, allowing the displacement of discrete portions of beam coupling member 190 to be determined by measuring the displacement of the distance "d" between the trilobal force sensor segments in the corresponding flexible circuits 180 and 110 (assuming the spring constant of beam coupling member 190 is known prior to installation). Alternatively, after final assembly, balloon catheter 300 can be tested to determine the constant k, taking into account the effects of protective sleeve 344, irrigation line 334, guide wire 336, and any other components functionally connected in parallel with beam coupling member 190. The results of the test can be used to calibrate the force sensor to eliminate inaccuracies caused by variations in assembly or manufacturing of the components.

[0111] from Figure 10FAs can be seen, each of the trilobate force sensor segments 160, 162, 164 of the flex circuit 110 is mounted in the beam coupling member 190 such that each segment 160, 162, 164 has a counterpart segment comprising the flex circuit 180. For example, segment 162 of the flex circuit 110 is mounted parallel to segment 182 of the flex circuit 180 at a specified distance "d" (this distance "d" may change when a force is applied to the coupling 316 or 314). The remaining force sensor coil segments 162 and 164 of the flex circuit 110 are mounted in a similar manner to the corresponding trilobate force sensor segments of the flex circuit 180. The displacement of each pair of trilobate force sensor segments will allow the console 24 to determine the angle and direction of the force applied to one coil segment of the pancake-shaped force sensor coil segment pair. For example, when the distance "d" ( Figure 10F ) changes while the distances on the other two pairs of force sensor coil segments do not change. The system's processor can determine that the force sensor is moving in the direction indicated by the double-headed arrow ( Figure 10F ) to apply force in one of the directions specified by .

[0112] Now see Figure 11 and Figure 12 , these figures are Figure 9 Translucent view of the sensor of the balloon catheter 300. The force sensor 312 is composed of a beam coupling member 190, wherein the first portion 114 ( Figure 3 ) is disposed on the bottom surface of the beam coupling member 190, and the flexible circuit 180 is disposed on the top surface of the beam coupling member 190. In some embodiments, the first portion 114 is disposed on the top surface, and the flexible circuit 180 is disposed on the bottom surface. Figures 2 to 8 The beam coupling members 190 and the various components of the flexible circuits 110 , 180 are described in detail.

[0113] Figure 11 A pad area 320 is shown that includes a plurality of pads (eg, about eleven pads) that may include a pad for attaching the coil ( Figure 3 ) and optionally a coil of flexible circuit 180 connected to console 24 ( Figure 1 ) of the portion 142 of the welding point 168 ( Figure 2 ). Figure 12 The x-axis coil 322 and the y-axis coil 324 are shown as forming part of the position sensor 318. The x-axis coil 322 and the y-axis coil 324 may be referred to above with reference to FIG. Figure 2 and Figure 3 Segments 122, 124, 132 and 134 are formed as described in more detail.

[0114] Now see Figure 13 , the figure is included using Figure 9Balloon Catheter 300 Operation Figure 1 400 of the steps in the method of the system 10. The following steps do not need to be performed in the order described. These steps can be performed in any suitable order. Some of these steps can be performed in parallel with each other.

[0115] Processor 22( Figure 1 ) is configured to receive signals from the force sensor 312 ( Figures 9 to 12 ) force signal (block 402). Processor 22 ( Figure 1 ) is configured to calculate the magnitude and direction of the force measured by the force sensor 312 in response to the force signal (block 404).

[0116] Force sensor 312 can be calibrated using any suitable method. According to some embodiments, distal tip 304 is held in a fixture or other device while inflatable balloon 306 is deflected using a robot. The robot measures the lateral and angular displacement of inflatable balloon 306 relative to distal tip 304, the corresponding force applied to inflatable balloon 306 by the robot using strain gauges, and the corresponding force signal provided by force sensor 312. The robot can also perform the above measurements while applying force from different directions about the axis of inflatable balloon 306. The calibration measurements can then be stored in a table or the like for future reference. Thus, during use of system 10, the magnitude and direction of the force applied by inflatable balloon 306 can be calculated by looking up the corresponding value in a table and performing appropriate interpolation or extrapolation of the value present in the table to calculate the force signal output by force sensor 312. The force signal also indicates the lateral and angular displacement of the inflatable balloon 306 relative to the distal tip 304, and therefore can be used to determine the lateral and angular displacement of the inflatable balloon 306 relative to the distal tip 304, and therefore determine the positioning (position and orientation) of the inflatable balloon 306 (described in more detail below).

[0117] Processor 22( Figure 1 ) is configured to receive data from the position sensor 318 ( Figure 9 Figure 10 Figure 12 ) and / or electrode 310 ( Figure 9 and FIG. 10 ) position signal (block 406). Processor 22 ( Figure 1 ) is configured to calculate the position of distal tip 304 in response to the position signal (block 407). Processor 22 is configured to calculate the position (position and orientation) of inflatable balloon 306 in response to the calculated position of distal tip 304 and the force signal (which generates lateral and angular displacement of inflatable balloon 306 relative to distal tip 304) (block 408).

[0118] Processor 22( Figure 1 ) is configured to receive signals from electrode 310 ( Figure 9and FIG. 10 ) contact signal (block 410). The processor 22 ( Figure 1 ) is configured to evaluate the respective contact quality of each of the electrodes 310 with the tissue in response to the contact signal (block 412).

[0119] Now see Figure 14 , the figure shows Figure 9 Schematic diagram of a balloon catheter 300 representation 502 and a force vector representation 504. See also Figure 13 .

[0120] Processor 22( Figure 1 ) is configured to present a representation 504 of the force vector to the display 29 in response to the calculated magnitude and direction, and to adjust the inflatable balloon 306 in response to the calculated position of the distal tip 304 (which is based on the calculated position of the distal tip 304 and the one or more force signals, as described above in conjunction with Figure 13 408) presents the inflatable balloon 306 ( Figure 9 ) (block 414), while modifying the electrode 310 ( Figure 9 ) in a visual feature of one or more electrodes. Electrodes 310 having a contact quality higher than a given contact quality are highlighted compared to other electrodes 310. Figure 14 The electrodes in FIG. 1 are labeled with reference numeral 510. The highlighted electrodes may be displayed in a different color and / or with greater brightness and / or with a border or in any suitable manner to distinguish electrodes 310 having a contact quality higher than a given contact quality compared to other electrodes 310. The electrodes 310 may be labeled with electrode numbers 508 to allow the operator 16 to easily identify which electrodes are in contact with the tissue. Figure 14 , highlighted electrodes include electrode numbers 508, while non-highlighted electrodes do not include electrode numbers 508. In some embodiments, both the highlighted and non-highlighted electrodes can be numbered. The representation 502 of the balloon catheter 300 and the representation 504 of the force vector can also be displayed along with an image 506 of the body part into which the balloon catheter 300 is inserted. The image 506 of the body part can be obtained from a CT or MRI scan or from a body part that has been connected to the system 10 ( Figure 1 ) any suitable scan acquisition pre-registered. Steps 402-414 may be performed in any suitable order and may be repeated intermittently or periodically to update the position of the balloon catheter 300 relative to the body part and / or the size and magnitude of the force vector.

[0121] For clarity, various features of the invention described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, for simplicity, various features of the invention are described in the context of a single embodiment and may also be provided separately or in any suitable subcombination.

[0122] The above embodiments are cited by way of example, and the present invention is not limited by what has been specifically shown and described hereinabove. On the contrary, the scope of the present invention includes combinations and subcombinations 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, comprising: A balloon catheter configured to be inserted into a body part of a living subject, the balloon catheter comprising: an insertion tube having a distal tip; a force sensor coupled to the distal tip; and an inflatable balloon comprising: a proximal portion connected to the force sensor such that the force sensor is disposed between the distal end of the insertion tube and the inflatable balloon; and a plurality of electrodes disposed about an outer surface of the balloon and configured to contact tissue at corresponding locations in the body part when the balloon is inflated; wherein the force sensor is configured to output at least one force signal indicative of a magnitude and direction of a force exerted by the balloon on the tissue when the balloon is inflated; Display; and A processing circuit, the processing circuit being configured to: receiving a contact signal from the electrode; evaluating a respective contact quality of each of the electrodes with the tissue in response to the contact signal; responsive to the at least one force signal, calculating a magnitude and direction of the force; and Responsive to the at least one force signal, a representation of a force vector and a representation of the inflatable balloon are presented to the display, while a visual characteristic of at least one of the electrodes is modified in response to the respective quality of contact of the electrode with the tissue at the respective location.

2. The system according to claim 1, wherein: The balloon catheter further includes at least one position sensor configured to output at least one position signal indicative of a position of the distal tip; The processing circuit is configured to: calculating a position of the distal tip in response to the at least one position signal; as well as A representation of the force vector is presented to the display in response to the calculated magnitude and direction, and a representation of the inflatable balloon is presented to the display in response to the calculated position and the at least one force signal.

3. The system according to claim 1, wherein: Each of the electrodes is a flexible electrode formed of a polyamide substrate on which gold is covered.

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