Integrated LC filter in the distal end of the catheter

Abstract

A distal assembly of a medical device includes a flexible substrate and an electrical conductor. The flexible substrate is configured to be coupled to a distal end of an insertion tube. The electrical conductor is disposed on the flexible substrate and is shaped to form: (i) one or more electrodes configured to exchange electrical signals with a proximal end of the medical device, and (ii) one or more printed filters disposed adjacent to at least one of the electrodes and configured to filter signals within a predetermined frequency range from the electrical signals exchanged between at least one of the electrodes and the proximal end.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is related to U.S. Patent Application Attorney Docket No. BIO5855USNP, entitled "Integrated resistive filters in catheter distal end," filed on even date herewith, the disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates generally to medical devices, and more particularly to filters integrated into a distal end of a catheter for eliminating interference. Background Art

[0004] In various medical procedures, a medical tool is inserted into a patient's body while being scanned using an anatomical imaging system such as a magnetic resonance imaging (MRI) system. The medical tool may include electrodes for performing the procedure. Various techniques for producing catheter electrodes operable in an MRI environment are known in the art.

[0005] For example, US Patent Application Publication No. 2015 / 0366508 describes a flexible PCB catheter device configured to be inserted into a body cavity. The flexible PCB catheter includes an elongated shaft, an expandable assembly, a flexible printed circuit board (flex PCB) substrate, a plurality of electronic components, and a plurality of communication paths.

[0006] U.S. Patent Application Publication 2014 / 0024909 describes an MRI-compatible catheter comprising a shaft having opposed distal and proximal portions. One or more RF tracking coils are positioned adjacent the distal portion and each comprises a conductive lead that electrically connects the RF tracking coil to an MRI scanner. The catheter comprises one or more sensing electrodes at the shaft distal portion, each sensing electrode being electrically connected to a resistor having a high impedance. Summary of the invention

[0007] Embodiments of the invention described herein provide a distal component of a medical device, the distal component comprising a flexible substrate and an electrical conductor. The flexible substrate is configured to be coupled to the distal end of an insertion tube. The electrical conductor is disposed on the flexible substrate and is shaped to form: (i) one or more electrodes configured to exchange electrical signals with a proximal end of the medical device, and (ii) one or more printed filters shaped to form at least one resistor disposed adjacent to at least one of the electrodes and configured to filter signals within a predetermined frequency range from electrical signals exchanged between at least one of the electrodes and the proximal end.

[0008] In some embodiments, the predetermined frequency range includes at least a portion of a radio frequency (RF) frequency range. In other embodiments, the signal filtered within the predetermined frequency range is caused by a magnetic resonance imaging (MRI) system. In other embodiments, the flexible substrate includes a flexible printed circuit board (PCB).

[0009] In an embodiment, the flexible substrate is configured to wrap around the distal end of the insertion tube. In another embodiment, one or more of the printed filters are coupled to at least one of the electrodes. In yet another embodiment, at least one of the printed filters is configured to transmit an electrical signal sensed from the patient's tissue by at least one of the electrodes.

[0010] In some embodiments, at least one of the printed filters is configured to pass an ablation signal to be applied to patient tissue. In other embodiments, the predetermined frequency range includes 58 MHz-70 MHz.

[0011] In an embodiment, the one or more printed filters are made of one or more materials selected from the list consisting of an alloy comprising nickel and chromium, an alloy comprising copper and nickel, and titanium. In another embodiment, at least one of the printed filters is configured to reduce one or more of: heating in the medical device, artifacts in images acquired using the medical device, and interference of the filtered signal with an electrical signal exchanged between at least one of the electrodes and the proximal end.

[0012] According to an embodiment of the present invention, there is also provided a method for producing a distal component of a medical device, the method comprising disposing a first electrical conductor on a flexible substrate, the first electrical conductor being shaped to form one or more electrodes for exchanging electrical signals with the proximal end of the medical device. One or more second electrical conductors are disposed adjacent to at least one of the electrodes. The second electrical conductors are shaped to form one or more printed filters, the printed filters comprising at least one resistor designed to filter signals within a predetermined frequency range from electrical signals exchanged between at least one of the electrodes and the proximal end. The flexible substrate is coupled to the distal end of the insertion tube.

[0013] According to an embodiment of the present invention, there is also provided a distal component of a medical device, the distal component comprising a flexible substrate and an electrical conductor. The flexible substrate is configured to be connected to the distal end of an insertion tube. The electrical conductor is disposed on the flexible substrate and is shaped to form: (i) one or more electrodes configured to exchange electrical signals with the proximal end of the medical device; and (ii) one or more printed filters disposed adjacent to at least one of the electrodes and configured to filter signals within a predetermined frequency range from the electrical signals exchanged between at least one of the electrodes and the proximal end.

[0014] In some embodiments, at least one of the printed filters is shaped to form at least one of an inductor and a capacitor. In other embodiments, the inductor and the capacitor are connected in parallel. In other embodiments, the predetermined frequency range includes at least a portion of a radio frequency (RF) frequency range.

[0015] In an embodiment, the signal filtered within the predetermined frequency range is caused by a magnetic resonance imaging (MRI) system. In another embodiment, the flexible substrate comprises a flexible printed circuit board (PCB). In yet another embodiment, the flexible substrate is configured to be wrapped around the distal end of the insertion tube.

[0016] In some embodiments, one or more of the printed filters are coupled to at least one of the electrodes. In other embodiments, at least one of the printed filters is configured to transmit an ablation signal to be applied to patient tissue.

[0017] In an embodiment, the predetermined frequency range includes 58 MHz-70 MHz. In another embodiment, at least one of the printed filters is configured to reduce one or more of: heating in the medical device, artifacts in images acquired using the medical device, and interference of the filtered signal with electrical signals exchanged between at least one of the electrodes and the proximal end.

[0018] According to an embodiment of the present invention, there is also provided a method for producing a distal component of a medical device, the method comprising disposing a first electrical conductor on a flexible substrate, the first electrical conductor being shaped to form one or more electrodes for exchanging electrical signals with a proximal end of the medical device. One or more second electrical conductors are disposed adjacent to at least one of the electrodes. The second electrical conductors are shaped to form one or more printed filters, the printed filters being designed to filter signals within a predetermined frequency range from electrical signals exchanged between at least one of the electrodes and the proximal end. The flexible substrate is coupled to the distal end of the insertion tube.

[0019] The present invention will be more fully understood through the following detailed description of embodiments of the present invention in conjunction with the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic illustration of a catheter insertion system according to an embodiment of the present invention;

[0021] Figure 2 is a schematic illustration of a flexible substrate having electrodes and filters printed thereon according to an embodiment of the present invention;

[0022] Figure 3 and Figure 4 is a schematic illustration of a filter formed in a corresponding flexible substrate according to an embodiment of the present invention;

[0023] Figure 5 is a schematic exploded illustration of a distal assembly of a catheter according to an embodiment of the present invention; and

[0024] Figure 6 is a flow chart schematically illustrating a method for producing a catheter including an electrode and a filter integrated on a flexible substrate according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] Overview

[0026] Some medical procedures involve real-time anatomical imaging, performed, for example, using a magnetic resonance imaging (MRI) system.Medical devices that may be used simultaneously with imaging may include catheters having electrodes, for example, for conducting electrical signals to or from patient tissue.

[0027] MRI systems apply pulsed radio frequency (RF) fields to change the direction of the magnetic field in the tissue, thereby inducing a signal in the antenna (receiving coil) at a specific frequency. The frequency required to induce a response from the tissue magnetization depends on the field strength of the externally applied magnetic field. For example, at a magnetic field of 1.5 Tesla, the RF frequency is approximately 64 MHz. Unless accounted for, the RF field of the MRI system may induce undesirable RF signals in the catheter wiring and / or electrodes, thereby distorting the desired signal of the catheter, producing image artifacts on the MRI scan, and producing undesirable heating along the catheter.

[0028] Embodiments of the invention described below provide a catheter suitable for operation in an MRI environment. Specifically, the catheter includes a filter for eliminating RF interference caused by the MRI system, which can interfere with the electrical signals of the electrodes. A method for producing a catheter with an integrated filter is also described below.

[0029] In some embodiments, the catheter may include a distal assembly made from a flexible substrate, such as a flexible printed circuit board (PCB) sheet coupled to the distal end of the insertion tube.

[0030] In some embodiments, electrical traces are placed on a PCB sheet in a suitable pattern to form electrodes, as well as filters designed to eliminate interference with the electrodes due to activity of the MRI system.

[0031] The electrodes are configured to exchange electrical signals with the proximal end of the catheter, and the filter is formed adjacent to the electrodes and configured to filter out RF signals that interfere with the exchanged electrical signals.

[0032] In some embodiments, the electrodes are configured to sense electrical signals from the patient's heart, in which case the filter comprises a resistor. In other embodiments, the electrodes are configured to apply an ablation signal to tissue of the patient's heart, and the filter comprises an inductor L and a capacitor C interconnected in parallel in an LC circuit configuration.

[0033] In some embodiments, electrodes and filters are manufactured using very large scale integration (VLSI) processes. In embodiments, electrical traces are formed by depositing one or more conductive layers on the outer surface of the PCB sheet, such as by using one or more physical vapor deposition (PVD) processes.

[0034] In an embodiment, the deposited conductive layer is shaped using a suitable patterning process such as photolithography and etching to form electrodes and filters. Subsequently, the distal assembly is produced by wrapping the PCB sheet around the insertion tube.

[0035] The disclosed technology helps improve the functionality of medical catheters to perform complex life-saving procedures, such as electrophysiology (EP) mapping and tissue ablation, while performing advanced imaging procedures, such as MRI.

[0036] The disclosed technology enables the characteristics of the filter integrated into the distal end of the catheter to be customized by forming a suitable circuit on a PCB sheet using, for example, a VLSI process. For example, to filter out a first frequency range, the filter may include a single resistor, while to filter out a second frequency range, the filter may include a parallel LC circuit.

[0037] System Description

[0038] Figure 1 2 is a schematic illustration of a catheterization system 20 according to an embodiment of the present invention. The system 20 includes a medical device such as a probe (in this example, a cardiac catheter 22) and a console 24. In the embodiments described herein, the catheter 22 can be used for any suitable therapeutic and / or diagnostic purpose, such as ablating tissue or sensing electrophysiological (EP) signals from a heart (not shown) of a patient 28.

[0039] In some embodiments, system 20 includes a magnetic resonance imaging (MRI) system 38 configured to generate anatomical images of patient tissue. In some embodiments, MRI system 38 includes a magnetic field coil (not shown) including field gradient coils that together generate a spatially varying magnetic field.

[0040] The spatially varying magnetic field provides spatial localization for radio frequency (RF) signals generated in the system.In some embodiments, MRI system 38 generates RF signals at a frequency of approximately 64 megahertz (MHz) or any other suitable RF frequency range.

[0041] In addition, the MRI system 38 includes transmit and receive coils (not shown). In the transmit mode, the transmit coil radiates RF pulse energy to the patient 28, and the RF pulse of energy interacts with the nuclear spins of the patient's tissue and thereby readjusts the magnetic moment of the nucleus away from its equilibrium position. In the receive mode, the receive coil detects the RF signal received from the patient's tissue as the tissue nuclei relax to their equilibrium state.

[0042] In some embodiments, console 24 includes a processor 34 , typically a general purpose computer, with suitable front end and interface circuitry for receiving signals from MRI system 38 and from catheter 22 and for controlling other components of system 20 .

[0043] In some embodiments, console 24 also includes memory 50 and display 46 configured to display data, such as image 44 of at least a portion of the heart of patient 28. In some embodiments, image 44 may be acquired using MRI system 38 or using any other suitable anatomical imaging system.

[0044] A physician 30, such as an interventional cardiologist, inserts a catheter 22 through the vascular system of a patient 28 lying on an operating table 29. The catheter 22 includes a distal assembly 40, which is shown in inset 26 and is located below. Figure 2 and Figure 5 The physician 30 moves the assembly 40 near the target location in the heart by manipulating the catheter 22 using a manipulator 32 near the proximal end of the catheter 22. The proximal end of the catheter 22 is connected to an interface circuit in a processor 34.

[0045] In some embodiments, position sensing techniques are generally used to measure the position of distal assembly 40 within the heart chamber. Such position sensing methods are, for example, available in the CARTO TM The invention is implemented in the system and is described in detail in U.S. Patents 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612 and 6,332,089, in PCT Patent Publication WO96 / 05768, and in U.S. Patent Application Publications 2002 / 0065455A1, 2003 / 0120150A1 and 2004 / 0068178A1, the disclosures of which are incorporated herein by reference.

[0046] In some embodiments, console 24 includes drive circuitry 42 that drives magnetic field generator 36 that is placed at a known location external to patient 28 lying on operating table 29 (eg, beneath the patient's torso).

[0047] Now refer to Figure 26. In some embodiments, the distal assembly 40 includes a flexible printed circuit board (PCB) sheet 60 wrapped around an inner member 69, at the bottom. Figure 5 The inner member is also referred to herein as the insertion tube.

[0048] In some embodiments, assembly 40 further includes a dome cover 66 made of a flexible PCB and configured to be wrapped around the annular dome support (underneath) using any suitable attachment technique. Figure 5 ) around.

[0049] In some embodiments, the PCB sheet 60 and / or dome cover 66 may be perforated to form one or more irrigation holes 64 configured to allow irrigation fluid to flow from the insertion tube when irrigating tissue of the heart, such as during an ablation procedure.

[0050] In some embodiments, assembly 40 further includes one or more microelectrodes 62 and ring electrodes 80 configured to exchange electrical signals with the proximal end of catheter 22 and conduct the electrical signals to or from cardiac tissue. During a medical procedure such as cardiac EP mapping or tissue ablation, microelectrodes 62 and ring electrodes 80 are brought into contact with cardiac tissue to sense electrical signals generated thereby, or to apply ablation signals for ablating tissue, as described below.

[0051] In the context of the present disclosure and the claims, the terms "electrode" and "microelectrode" are used interchangeably and refer to a sensing electrode or an ablation electrode configured to sense electrical signals from the heart or to ablate tissue of the heart, respectively.

[0052] In some embodiments, ring electrode 80 may be used to sense electrocardiogram (ECG) signals or any other type of signal from the heart of patient 28. Note that the following description primarily refers to microelectrodes 62, but is also applicable to ring electrode 80.

[0053] In some embodiments, microelectrodes 62 are coated with a conductive layer (made of, for example, gold or any other suitable material) and are configured to transmit electrical signals to / from cardiac tissue at a predetermined frequency range.

[0054] In some embodiments, assembly 40 can be used to ablate tissue of the heart. In some embodiments, during ablation, microelectrodes 62 are configured to deliver electrical signals to the tissue at a given frequency range.

[0055] In some embodiments, the conductive layer of the microelectrodes 62 is typically deposited on the outer surface of the PCB sheet 60. In other embodiments, the conductive layer can be deposited on the dome cover 66 in addition to the PCB sheet 60, or in lieu of the PCB sheet 60.

[0056] As described above, MRI system 38 generates RF signals, such as at a predetermined frequency of 64 MHz, which may interfere with electrical signals exchanged between microelectrodes 62 and the proximal end of catheter 22, resulting in image artifacts (eg, in image 44), as well as undesirable heating along the catheter.

[0057] In some embodiments, one or more filters (in the following Figures 2 to 4 ) is disposed (eg, printed) on a PCB sheet 60 adjacent to at least one of the microelectrodes 62. Typically, each electrode is associated with one or more corresponding filters.

[0058] In an embodiment, the filter is configured to filter a predetermined frequency range so as not to interfere with the electrical signals exchanged between the corresponding microelectrode and the proximal end. In some embodiments, the frequency range may include a frequency of about 64 MHz generated by the MRI system 38, which has a magnetic field strength of 1.5 Tesla. In the following Figures 2 to 6 An example method for producing distal assembly 40 and further details regarding the filter are described in detail in .

[0059] In some embodiments, filters and other components of the catheter, such as one or more thermocouples (not shown), can be created between conductive layers of PCB sheet 60 or mounted on an outer surface of PCB sheet 60. Thermocouples can be used to monitor tissue temperature during ablation.

[0060] In some embodiments, processor 34 typically comprises a general purpose processor that is programmed with software to perform the functions described herein. The software may be downloaded to a computer in electronic form over a network, for example, or it may alternatively or additionally be disposed and / or stored on a non-transitory tangible medium such as a magnetic memory, an optical memory, or an electronic memory.

[0061] Figure 1 The configuration of the distal assembly 40 shown in is merely an example configuration selected for conceptual clarity. In alternative embodiments, any other suitable configuration may also be used. For example, the size and shape of the distal assembly 40 and the number and position of the microelectrodes 62 and corresponding filters may be implemented using any suitable components and layouts suitable for performing a suitable medical procedure on the tissue of any organ of the patient 28. In addition, the flexible substrate used to implement the distal device may include any other suitable substrate other than a PCB.

[0062] Integrate the filter into the distal end of the catheter

[0063] Figure 2 4 is a schematic illustration of a flexible substrate 48 according to an embodiment of the present invention. In some embodiments, the substrate 48 includes a single section that can be used to produce a single unit of the distal assembly 40. In other embodiments, the substrate 48 can include one or more substantially similar sections (not shown) for producing multiple corresponding units of the distal assembly 40.

[0064] In some embodiments, each section of the substrate 48 includes a PCB sheet 60, a cover 66, and an upper surface. Figure 1 All other components of the assembly 40 depicted in FIG. 4 are shown in FIG. 4A. These embodiments are implemented by applying the reference above Figure 1 A set of very large scale integration (VLSI) processes for producing multiple segments simultaneously is described to enable high volume manufacturing (HVM) of assembly 40 .

[0065] In some embodiments, the VLSI process may include depositing one or more conductive layers at selected locations on the outer surface of PCB sheet 60 using any suitable process such as physical vapor deposition (PVD). For example, the deposited conductive layers are shaped to form various components integrated on PCB sheet 60 and dome cover 66 using patterning processes such as photolithography and etching.

[0066] After the production of the segments is completed, the substrate 48 is cut so that each segment is separated from its adjacent segments. Figure 2 In the example shown, substrate 48 includes a single singulated section.

[0067] In some embodiments, the PCB sheet 60 typically includes electrical interconnects, such as conductive traces 52, configured to electrically connect electronics coupled to the substrate 48 to appropriate wires traversing the catheter and between the catheter 22 and the proximal end of the electrode 62.

[0068] In some embodiments, one or more filters 70 are printed on the PCB sheet 60, adjacent to the corresponding microelectrode 62. In some embodiments, the filter 70 is configured to filter out interfering signals within a predetermined frequency range (e.g., 58 MHz-70 MHz). Figure 3 , the filter 70 may include an inductor L and a capacitor C interconnected in parallel. In this embodiment, the LC circuit may act as a band-stop filter for high impedance signals centered at 64 MHz.

[0069] In other embodiments, the filter 70 substantially uniformly attenuates interfering signals throughout the useful frequency range. In an embodiment, the filter 70 may include a resistor R coupled to the electrode 62 and the trace 52. In this embodiment, the resistor R is configured to attenuate currents of all frequencies conducted on the trace 52, but attenuate low currents, such as picoampere (pA) currents. The reduction of high currents reduces image artifacts during MRI scanning (e.g., on the image 44) and reduces undesirable heating along the catheter 22.

[0070] Interference signals are generated by the MRI system 38 and are filtered out in order to reduce or even eliminate interference they may cause to the electrical signals exchanged between the microelectrodes 62 and the proximal end of the catheter 22 .

[0071] Note that interfering signals from the MRI system 38 or from any other source may interfere with the intended operation of the components of the system 20 and are typically conducted from the blood or tissue through the traces 52 to the microelectrodes 62 and into the catheter.

[0072] In some embodiments, each filter 70 is physically coupled to the microelectrode 62 such that the filter 70 is configured to block or substantially attenuate any interfering signals within a predetermined frequency range (e.g., 58 MHz-70 MHz) that would otherwise be conducted between the microelectrode 62 and the proximal end of the catheter 22 via the trace 52.

[0073] In some embodiments, the filter 82 is printed on the PCB sheet 60, adjacent to the ring electrode 80. The filter 82 is configured to filter out interference signals within a predetermined frequency range (e.g., 58 MHz-70 MHz) so as to reduce the noise level of the ECG signal sensed by the ring electrode 80. In some embodiments, the filter 82 can have a structure similar to the filter 70 of the microelectrode 62. In alternative embodiments, the filter 82 can have any other suitable structure.

[0074] In principle, interfering signals can be blocked by implementing a filter of a predetermined frequency range at the proximal end of catheter 22 (e.g., at manipulator 32). However, such a configuration does not eliminate heating caused on the wires spanning the length of the catheter, nor does it address associated image artifacts. Therefore, the desired location for setting the filter so as to block interfering signals is as close as possible to the corresponding electrodes (e.g., electrodes 62 and 80) of distal assembly 40.

[0075] In some embodiments, microelectrodes 62 can be used to sense low voltage electrical signals, e.g., about 0.01 mV-1 mV, from the heart of patient 28. In these embodiments, first type filter 70 is adapted to filter interfering signals from MRI system 38. In other embodiments, the electrodes are configured to apply ablation to, for example, cardiac tissue using high current electrical signals, such as 50 mA-5 A.

[0076] In these embodiments, a second type of filter 70, different from the first type, is adapted to filter the interfering signal. Figure 3 to Figure 4 An implementation using filters of the first and second types is shown in detail in FIG.

[0077] In alternative embodiments, electrodes 62 may conduct any other type of electrical signal to or from any organ of patient 28 in the presence of interfering signals of any frequency range.

[0078] In these embodiments, for each type of electrical signal, system 20 may require a different type of filter suitable for blocking interfering signals having a corresponding frequency range.

[0079] In an embodiment, flushing holes 64 are formed in sheet 60 and / or dome cover 66 before being wrapped around member 69 and annular dome support when sheet 60 and cover 66 are in a planar position, as shown below. Figure 5 shown.

[0080] In some embodiments, the sheet 60 includes a section 54 that is configured to connect the edges of the sheet 60 to each other and between the PCB sheet 60 and the cover 66 when the sheet 60 is wrapped around the member 69, as will be described below. Figure 5 Described in .

[0081] In some embodiments, the cover 66 includes a plurality of protrusions 51 , each extending from a corresponding section 53 of the cover 66 and configured to couple between the domed cover 66 and the section 54 of the sheet 60 .

[0082] In some embodiments, some of the segments 54 and protrusions 51 include keep-out elements 57 formed in some of the protrusions 51 so as not to overlap the flushing aperture 64 when the sheet 60 and cover 66 are in a wrapped position around the member 69 .

[0083] In alternative embodiments, after wrapping, the left and right edges of sheet 60 may be coupled to one another by welding, adhesive, or using any other suitable technique to couple sheet 60 and cover 66 to member 69 and to one another.

[0084] In some embodiments, after the VLSI process is completed and before the sheet 60 and cover 66 are wrapped around the member 69 and on the apex of the assembly 40, respectively, the sheet 60 and cover 66 of the section 48 are shown in planar form, as will be described below. Figure 5 Described in detail.

[0085] Figure 3 6 is a schematic diagram of a filter 72 and an ablation electrode 63 formed on a PCB sheet 60 according to an embodiment of the present invention. The filter 72 and the ablation electrode 63 may replace the above-mentioned Figure 2 filter 70 and electrode 62.

[0086] In other embodiments, the electrodes 63 and the filter 72 may be formed in the cover 66 in addition to or instead of forming the electrodes 63 and the filter 72 on the PCB sheet 60 .

[0087] The process described below is suitable for producing electrodes 63 and filters 72 in sheet 60 and / or cover 66 .

[0088] In some embodiments, electrode 63 is delivering current and is configured to conduct ablation signals from the proximal end of catheter 22 to cardiac tissue of patient 28. In some embodiments, filter 72 is configured to pass ablation signals, e.g., from the proximal end of catheter 22 to electrode 63 for ablating patient tissue.

[0089] In an embodiment, the filter 72 comprises a parallel LC circuit including an inductor L and a capacitor C connected in parallel. Figure 3 In the example of FIG. 5 , one terminal of the filter 72 is coupled to the trace 52, and the other terminal of the filter is coupled to the electrode 63, similar to the above Figure 2 The interconnection configuration of the filter 70 in FIG.

[0090] In some embodiments, inductor L and capacitor C are made of electrical traces of one or more conductive layers, preferably gold or copper traces, deposited on PCB sheet 60 using a PVD process or any other suitable process. The conductive layers are deposited in suitable shapes to form the components comprising filter 72, for example, using photolithography and etching processes.

[0091] In some embodiments, the inductor L and capacitor C of the filter 72 may be patterned using a single mask that is configured to pattern other components of the PCB sheet 60 , such as the traces 52 and electrodes 63 .

[0092] In other embodiments, filter 72 may be formed using any other suitable sequence of deposition and patterning processes, such as using separate photolithographic masking and patterning processes.

[0093] In some embodiments, the filter 72 is configured to filter signals within a predetermined frequency range to prevent them from coupling to the trace 52, thereby causing catheter heating and image artifacts. In these embodiments, the frequency of the interfering signal includes the 64 MHz frequency generated by the 1.5T MRI system 38. In the case of different magnetic field strengths, the corresponding Larmor frequency will be used.

[0094] In some embodiments, the configuration of filter 72 is suitable for filtering out signals from interfering with the ablation signal, which has a typical current value of 50 mA to 5 A and a frequency range of 50 kHz to 25 MHz.

[0095] Note that small values ​​of inductance (eg, 1 nH to 1000 nH) and capacitance (eg, 5 pF to 5000 pF) are sufficient for the inductor L and capacitor C of the filter 72 to attenuate interfering signals from the MRI system 38 .

[0096] In other embodiments, any other suitable configuration of one or more inductors L and / or capacitors C and / or other components may be arranged to form a filter compatible with any type of electrodes formed on substrate 48. Furthermore, each component of filter 72 (e.g., capacitor C) may have any suitable value.

[0097] Figure 4 is a schematic illustration of a filter 74 and microelectrodes 65 formed in a PCB sheet 60 according to an embodiment of the present invention.

[0098] The filter 74 and the microelectrode 65 may replace the above Figure 2 filter 70 and microelectrode 62. In some embodiments, filter 74 includes a resistor R coupled to electrode 65 and trace 52.

[0099] In some embodiments, microelectrodes 65 are non-current carrying electrodes configured to sense electrical signals from tissue of the heart of patient 28. In an example of system 20, the electrical signals sensed by microelectrodes 65 have a current range of 1 pA-1 μA and a frequency range of 0.01 Hz-1000 Hz.

[0100] In some embodiments, filter 74 is configured to filter a predetermined frequency range so as not to interfere with the electrical signals of the cardiac tissue sensed by microelectrodes 65. In some embodiments, filter 74 is also configured to pass the electrical signals of the cardiac tissue sensed by microelectrodes 65 and conducted via traces 52 to processor 34.

[0101] Note that each filter 74 is formed in close proximity (eg, a few millimeters or even physically coupled) to the corresponding microelectrode 65 in order to filter the above-mentioned interference signals. The interference signals may be generated by the MRI system 38 or any other source.

[0102] In some embodiments, the resistor R is formed by patterning a suitable resistive layer between the trace 52 and the microelectrode 65. For example, the resistor R can be formed by shaping the width of a segment of the trace 52 so that it becomes narrower near the microelectrode 65. In this configuration, the segment of the trace 52 with a narrower width can have a higher resistance than other segments of the trace 52, thereby attenuating or completely preventing interfering signals from interfering with the cardiac signal sensed by the microelectrode 65.

[0103] In other embodiments, resistor R can be made of a material different from the material from which trace 52 is made, which has a higher inherent resistance than the material of trace 52, such as nichrome (an alloy comprising nickel and chromium), constantan (an alloy comprising copper and nickel), titanium, or any other suitable material.

[0104] In other embodiments, the resistor R may be fabricated by depositing less conductive material to form features with lower material thicknesses, or by selectively removing material, leaving behind thinner layers of material.

[0105] In other embodiments, any suitable combination of the above techniques may be applied to provide a desired resistance of resistor R. For example, narrow and thin features may be formed from a material having a higher intrinsic resistance.

[0106] Figure 3 and Figure 4 The configurations of filters 72 and 74 shown are depicted by way of example only. In alternative embodiments, substrate 48 of remote assembly 40 may include filters of any other type and configuration suitable for filtering any predetermined frequency range of interfering signals. The characteristics of such filters are defined by the type and arrangement of such components (e.g., a combination of RLC or RC circuits) and the characteristics of each component of the filter.

[0107] Figure 5 is a schematic exploded illustration of a distal assembly 40 according to an embodiment of the present invention. Figure 5 The sheet 60 and the cover 66 are shown with the top Figure 2 Surfaces opposite to each other are shown.

[0108] In some embodiments, the inner member 69 of the distal assembly 40 can be made of plastic or any other suitable material. The member 69 can have a Figure 5 A skeleton support structure as shown or any other suitable structure.

[0109] The base 58 is located at the proximal end of the member 69, the annular dome support 68 is located at the apex of the member 69, and a plurality of ribs 56 connect the base and the dome support. In this embodiment, the member 69 has an internal cavity for directing flushing into the interior of the cavity formed by the flexible PCB sheet 60.

[0110] In some embodiments, dome cover 66 can be glued to dome support 68, or the dome cover 66 can be glued to the dome support 68 using the above Figure 2 In an alternative embodiment, the cover 66 can be made of a liquid crystal polymer (LCP) PCB that can be formed (e.g., thermoformed) into a cup shape and bonded to the sheet 60. The cup shape can be bonded to the dome support 68 and the sheet 60 to the base 58 using any suitable bonding technique known in the art.

[0111] In some embodiments, sheet 60 and cover 66 are made of a single continuous PCB or any other suitable flexible substrate. In alternative embodiments, sheet 60 and cover 66 can be formed of separate pieces of material and connected to each other using welding or any other suitable connection technology.

[0112] Figure 6 1 is a flow chart schematically illustrating a method for producing a distal assembly 40 according to an embodiment of the present invention. The method begins by depositing a first conductive layer on a first selected location of a flexible substrate 48 at a first deposition step 100 .

[0113] At a second deposition step 102, a second conductive layer is deposited on the flexible substrate 48 at a second selected location adjacent to the first selected location. In some embodiments, the first conductive layer and the second conductive layer are made of the same material, such as gold or any other suitable material.

[0114] In these embodiments, the first conductive layer and the second conductive layer can be deposited simultaneously, so that steps 100 and 102 are performed as a single deposition step. In other embodiments, the first conductive layer and the second conductive layer are made of different corresponding materials and are typically deposited in different process steps.

[0115] In some embodiments, the first conductive layer is deposited over the entire surface of substrate 48 and then patterned so that only portions of the first conductive layer remain at first selected locations on flexible substrate 48. Similarly, the second conductive layer can be deposited over the entire surface of substrate 48 and then patterned so that only portions of the second conductive layer remain at second selected locations on flexible substrate 48.

[0116] After completing step 102, the first conductive layer and the second conductive layer are deposited adjacent to each other, typically in physical contact with each other.

[0117] At patterning step 104, the first conductive layer is shaped to form electrodes, such as microelectrodes 62, and the second conductive layer is shaped to form filters, such as filter 70. In an embodiment, the shaping of the first conductive layer and the second conductive layer is performed using a single patterning process.

[0118] In this embodiment, the patterning process may include the use of a single mask that defines the shapes of the microelectrodes 62 and the filter 70, followed by one or more etching steps configured to transfer the shapes defined by the mask.

[0119] In an alternative embodiment, the process sequence described in steps 100, 102 and 104 may include depositing a first conductive layer and patterning the shape of microelectrodes 62 using a first mask, and then depositing a second conductive layer and patterning the shape of filter 70 using a second mask.

[0120] For clarity, the description of the processes in steps 100, 102 and 104 above is simplified, and these example steps are depicted by way of example only. In alternative embodiments, any other suitable process may be used to produce microelectrodes 62 and filters 70 adjacent to or coupled to each other.

[0121] In some embodiments, at least one of the first conductive layer and the second conductive layer may include a multi-layer structure, each conductive layer being made of at least two types of sub-layers.

[0122] At the tip forming step 106, the above Figure 2 and Figure 5 4 and 5. The method of step 106 is used to couple substrate 48 to member 69 in one of the techniques depicted in FIG. In the example of distal assembly 40, flexible PCB sheet 60 is wrapped around base 58 and ribs 56, and dome cover 66 is wrapped around dome support 68. In some embodiments, step 106 ends the method and enables formation of distal assembly 40.

[0123] Although the embodiments described herein are primarily directed to the mapping and treatment of cardiac arrhythmias, the methods and systems described herein may also be used in other applications, such as in otolaryngology or neurology surgery.

[0124] It should therefore be understood that the embodiments described above are cited by way of example, and that the present invention is not limited to the contents specifically shown and described above. On the contrary, the scope of the present invention 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 when reading the above description, and which are not disclosed in the prior art. The documents incorporated by reference into this patent application are considered to be an integral part of this application, except that if any term defined in these incorporated documents conflicts with a definition explicitly or implicitly given in this specification, only the definition in this specification should be considered.

Claims

1. A distal component of a medical device, the distal component comprising: A flexible substrate configured to be coupled to a distal end of an insertion tube and comprising: a flexible printed circuit board sheet configured to be wrapped around the insertion tube; a dome cover configured to wrap around the annular dome support; and a plurality of protrusions extending from the dome cover and configured to couple the dome cover to the flexible printed circuit board sheet; and an electrical conductor disposed on the flexible substrate and shaped to form: (i) one or more electrodes configured to exchange electrical signals with a proximal end of the medical device, and (ii) one or more printed filters disposed adjacent to at least one of the electrodes and configured to filter signals within a predetermined frequency range from the electrical signals exchanged between the at least one of the electrodes and the proximal end.

2. The distal assembly of claim 1, wherein at least one of the printed filters is shaped to form at least one of an inductor and a capacitor.

3. The remote assembly of claim 2, wherein the inductor and the capacitor are connected in parallel.

4. The distal assembly of claim 1, wherein the predetermined frequency range includes at least a portion of a radio frequency (RF) frequency range.

5. The distal assembly of claim 1, wherein the signal filtered within the predetermined frequency range is caused by a magnetic resonance imaging (MRI) system.

6. The distal assembly of claim 1, wherein the flexible substrate comprises a flexible printed circuit board (PCB).

7. The distal tip assembly of claim 1, wherein the flexible substrate is configured to wrap around the distal end of the insertion tube.

8. The distal assembly of claim 1, wherein one or more of the printed filters are coupled to at least one of the electrodes.

9. The distal assembly of claim 1, wherein at least one of the printed filters is configured to transmit an ablation signal to be applied to patient tissue.

10. The remote assembly of claim 1, wherein the predetermined frequency range includes 58 MHz-70 MHz.

11. A distal component according to claim 1, wherein at least one of the printed filters is configured to reduce one or more of: heating in the medical device, artifacts in images acquired using the medical device, and interference of the filtered signal with the electrical signal exchanged between at least one of the electrodes and the proximal end.

12. A method for producing a distal assembly of a medical device, the method comprising: providing a first electrical conductor on the flexible substrate, the first electrical conductor being shaped to form one or more electrodes for exchanging electrical signals with a proximal end of the medical device; one or more second electrical conductors disposed adjacent to at least one of said electrodes, said second electrical conductors being shaped to form one or more printed filters, said printed filters being designed to filter signals within a predetermined frequency range from said electrical signals exchanged between said at least one of said electrodes and said proximal end; as well as coupling the flexible substrate to a distal end of an insertion tube; Wherein, the flexible substrate comprises: a flexible printed circuit board sheet configured to be wrapped around the insertion tube; a dome cover configured to wrap around the annular dome support; and A plurality of protrusions extend from the dome cover and are configured to couple the dome cover with the flexible printed circuit board sheet.

13. The method of claim 12, wherein disposing on the flexible substrate comprises shaping at least one of the printed filters to form at least one of an inductor and a capacitor.

14. The method of claim 13, wherein shaping the at least one of the printed filters comprises connecting the inductor and the capacitor in parallel.

15. The method of claim 12, wherein the predetermined frequency range comprises at least a portion of a radio frequency (RF) frequency range.

16. The method of claim 12, wherein the signal filtered within the predetermined frequency range is caused by a magnetic resonance imaging (MRI) system.

17. The method of claim 12, wherein disposing on the flexible substrate comprises disposing on a flexible printed circuit board (PCB).

18. The method of claim 12, wherein coupling the flexible substrate comprises wrapping the flexible substrate around the distal end of the insertion tube.

19. The method of claim 12, wherein providing one or more second electrical traces comprises coupling one or more of the printed filters to at least one of the electrodes.

20. The method of claim 12, wherein at least one of the printed filters has a response that conveys an ablation signal to be applied to patient tissue.

21. The method of claim 12, wherein the predetermined frequency range includes 58 MHz-70 MHz.

22. The method of claim 12, wherein setting the second electrical conductor comprises reducing one or more of: heating in the medical device, artifacts in images acquired using the medical device, and interference of the filtered signal with the electrical signal exchanged between the at least one of the electrodes and the proximal end.

Images