Guidewire with active electrode

Abstract

A medical device system may include a guidewire with a proximal end configured to be controlled by an operator to advance a distal end of the guidewire that includes at least one guidewire electrode. A medical device system also includes a processor coupled to the at least one guidewire electrode and configured to perform one or more of measurements and therapy delivery using the at least one guidewire electrode.

Description

GUIDEWIRE WITH ACTIVE ELECTRODETECHNICAL FIELD OF THE INVENTION

[0001] This disclosure relates to medical catheters, and more specifically to catheter devices with a guidewire.BACKGROUND

[0002] A catheter is an elongated tubular device often used to perform minimally invasive procedures such as cardiovascular and / or endovascular intervention. In some examples, a catheter may be used with a guidewire, which is a thin, flexible, metallic wire. In some examples, the guidewire operates as a pathfinder. The guidewire is inserted first, and helps a physician to steer through complex and narrow pathways within the body, such as arteries or veins. A catheter may include electrodes to perform measurements and / or to deliver therapy internal to a patient’s body.SUMMARY

[0003] A medical device system is provided including a guidewire with a proximal end configured to be controlled by an operator to advance a distal end of the guidewire. The medical device system further includes at least one guidewire electrode positioned at the distal end of the guidewire. The medical device system further includes a processor coupled to the at least one guidewire electrode and configured to perform one or more of measurements and therapy delivery using the at least one guidewire electrode.

[0004] The processor may be configured to use the at least one guidewire electrode to determine a position of the guidewire distal end. The processor may be configured to capture and process impedance signals from the guidewire electrode while the electrode is disposed in one or more controlled electrical and / or magnetic field(s). The processor may use the impedance signals from the guidewire electrode alone or in combination with magnetic-based localization signals to determine a position of the guidewire distal end relative to a three-dimensional (3D) reference grid.

[0005] The medical device system may include a magnetic sensor positioned at the distal end of the guidewire, wherein the processor is configured to use the magnetic sensor in combination with the guidewire electrode to determine a correlation of magnetic and impedance information in 3D space.

[0006] The processor may be configured to use the at least one guidewire electrode to determine whether the guidewire is in contact with tissue.

[0007] The processor may be configured to use the at least one guidewire electrode to measure changes in tissue resistance and / or impedance. The processor may be configured to detect whether the at least one guidewire electrode is in contact with tissue based on a change in resistance and / or impedance of signals from the at least one guidewire electrode.

[0008] The processor may be configured to use the at least one guidewire electrode as an anode or a cathode to deliver therapy to tissue.

[0009] The processor may be configured to measure electrical characteristics of tissue using the at least one guidewire electrode as a unipolar reference to remove far-field signals from signals detected by at least one catheter electrode.

[0010] The medical device system may include a catheter. The guidewire may be configured to be secured in a fixed position relative to the catheter. For example, the catheter distal end may include a mechanical locking mechanism that allows a position of the guidewire electrode(s) to be fixed relative to the catheter / catheter electrode(s).

[0011] The at least one guidewire electrode may be arranged at the distal end of the guidewire. The guidewire electrode may be a conductive tip of the guidewire. The guidewire electrode may be formed of a conductive material while other portions of the guidewire other than the electrode may be formed of a non-conductive material.

[0012] The medical device system may include one or more conductors in the guidewire that couple the at least one guidewire electrode to the processor at the proximal end of the guidewire. The one or more conductors may be arranged in one or more lumens of the guidewire.

[0013] A method is provided including advancing a guidewire with a proximal end configured to be controlled by an operator to advance a distal end of the guidewire that includes at least one guidewire electrode. The method further includes using the at least one guidewire electrode to perform one or more of measurements and therapy delivery.

[0014] The method may further include using the at least one guidewire electrode of the guidewire to determine a position of the distal end of the guidewire. The method may include capturing and processing impedance signals from the guidewire electrode while the electrode is disposed in one or more controlled electrical and / or magnetic field(s). The method may include using the impedance signals from the guidewire electrode alone or in combination with magnetic-based localization signals to determine a position of the guidewire distal end relative to a 3D reference grid.

[0015] The method may further include using a magnetic sensor positioned at the distal end of the guidewire in combination with the at least one guidewire electrode to determine a correlation of magnetic and impedance information in 3D space.

[0016] The method may further include using the at least one guidewire electrode to determine whether the guidewire is in contact with patient tissue.

[0017] The method may further include using the at least one guidewire electrode to measure changes in tissue resistance and / or impedance. The method may include detecting whether the at least one guidewire electrode is in contact with tissue based on measuring a change in resistance and / or impedance of signals from the at least one guidewire electrode.

[0018] The method may further include using the at least one guidewire electrode as an anode or a cathode to deliver therapy to tissue.

[0019] The method may further include measuring electrical characteristics of tissue using the at least one guidewire electrode as a unipolar reference to remove far-field signals from signals detected by at least one catheter electrode.

[0020] A guidewire is provided including a guidewire proximal end and a guidewire distal end. The guidewire further includes at least one guidewire electrode positioned along a length of the guidewire and used to perform one or more measurements or delivery therapy to a patient.

[0021] The at least one guidewire electrode may be configured to be used to perform measurement to determine one or more of: a position of the guidewire, a resistance of patient tissue; whether the at least one guidewire electrode is in contact with patient tissue, and an electrocardiogram waveform.

[0022] The techniques described herein relate to a guidewire, wherein the at least one guidewire electrode may be configured to be used as one or more of an anode and cathode to deliver ablation therapy to a patient.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 depicts one example of a catheter that may be used as part of a medical device system.

[0024] FIG. 2 is a block diagram that depicts one example of a medical device system that includes a catheter with a catheter distal end and a guidewire with one or more guidewire electrode(s).

[0025] FIG. 3 is a diagram depicting a medical device system being used as part of a medical procedure.

[0026] FIG. 4 is a block diagram that depicts one example of a medical device system 400 that includes a guidewire with one or more guidewire electrode(s).

[0027] FIG. 5 is a block diagram that depicts one example of a medical device system that uses one or more guidewire electrode(s) to localize (i.e.. determine a position and / or orientation) a guidewire.

[0028] FIG. 6 is a block diagram that depicts one example of medical device system that uses one or more guidewire electrode(s) to measure a resistance of patient tissue.

[0029] FIG. 7 is a block diagram that depicts one example of medical device system that uses one or more guidewire electrode(s) to detect at least part of an electrocardiogram (EGM) waveform.

[0030] FIG. 8 is a block diagram that depicts one example of medical device system 800 that uses one or more guidewire electrode(s) to deliver therapy to a patient.

[0031] FIG. 9 is a flow diagram that depicts one example of a method of using a guidewire of a catheter.DETAILED DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 depicts one example of a catheter 130 that may be used as part of a medical device system. The catheter 130 includes is a thin, flexible catheter tube 131 with a catheter distal end 134 that can be inserted into the body of a patient to perform a range of functions including performing measurements and / or the delivery of therapy. The catheter tube 131 extends through a main body 110, a portion of which is shown in the FIG. 1 example. The catheter distal end 134 may include electrodes (not shown in FIG. 1). As shown in FIG. 1. a guidewire 220 extendsthrough a lumen in the catheter 130. As shown in FIG. 1 , the guidewire includes an electrode 125. In the FIG. 1 example, the electrode 125 is a conductive tip 129 of the guidewire 120. In other examples not depicted, the electrode 125 may be positioned elsewhere on a surface of the guidewire 220 other than the tip of the guidewire 120.

[0033] The catheter 130 may be used to perform measurements or deliver therapy such as to measure electrical signals, pressure, or the like associated with the heart or blood vessels, deliver drugs locally to perform ablation therapy and / or for other purposes associated with the health of a patient. In some examples, the catheter distal end 134 may be configured to expand as shown in FIG. 1 to treat a medical condition (e.g., to open a blocked artery or vein), to bring electrodes in contact with patient tissue, and / or to secure the catheter 130 in a position within a patient.

[0034] FIG. 2 is a block diagram that depicts one example of a medical device system 200 that includes a catheter 230 with a catheter distal end 234 and a guidewire 220 with one or more guidewire electrode(s) 225. System 200 may be configured to work with the catheter 130 depicted in FIG. 1 or other types of catheters, including those that do not include an expandable distal end. In the example of FIG. 2, the catheter distal end 234 includes one or more electrode(s) 235 that are coupled through conductor(s) 215 to one or more processor(s) 250.

[0035] The catheter distal end 234 is configured to be advanced to a desired position within a patient along a guidewire 220 arranged in one or more lumens (e.g., a central lumen) of the catheter 230. Conductors 217 are positioned in the guidewire 220. For example, the conductors 217 may be arranged in one or more lumens (not shown) of the guidewire 220. The processor(s) 250 are coupled to the electrode(s) 235 via conductors 217 and configured to execute instructions to perform one or more functions of medical device system 200, some of which are represented by modules 202-208 in the FIG.2 example. FIG. 3 is a diagram depicting a medical device system being used as part of a medical procedure.

[0036] In the example of FIG.2, the processor(s) 250 of medical device system 200 are configured to implement an input output interface 202, a patient monitor module 203, a therapy delivery module 204, a localization module 205, and an imaging module 208. The input / output interface(s) 202 of the medical device system 200 may include any conventional means of human machine interfaces to enable a physician or other operator of system 200 to communicate with system. For example, the input / output interface 202 may include means for providing user input such as a keyboard, mouse, touchscreen, or microphone. As another example, medical device system 200may include one or more conventional output devices such one or more displays 316 as shown in FIG. 3, audio speakers, and / or haptic feedback mechanisms implemented via a computing device such as one or more of a desktop computer, a laptop computer, a smartphone, a tablet, a wearable computing device, or the like that is communicatively coupled to system 200 and used as a user interface.

[0037] In the example of FIG. 2. the patient monitor module 203 is configured to monitor signals from electrode(s) 235 at the catheter distal end 234 which may be coupled to sense circuitry (not shown) of the medical device system 200 through one or more conductor(s) 215 disposed in one or more lumens of the catheter 230. As one example, where catheter 230 is disposed in proximity to cardiac tissue within a patient, the electrode(s) 235 may be used to sense electrical signals associated with cardiac activity. As one specific example, the medical device system 200 may include an ECG monitor that uses monitored signals from the electrode(s) 235 to generate an electrocardiogram signal that represents the cardiac rhythm of a patient. Such an electrocardiogram signal may be output by system 200 via the input / output interface(s) 202, e.g., via one or more displays 316 visible to a physician or other operator of medical device system 200.

[0038] As also shown in FIG. 2, medical device system 200 may also include a therapy delivery module 204 configured to deliver therapy to a patient. The therapy delivery module 204 may cause electrical energy to be delivered to the electrode(s) 235 through the conductor(s) 215 to, for example, ablate cardiac or other patient tissue as a therapy. In other examples, medical device system 200 may be used to perform other types of therapy, including localized drug delivery and / or to remove blockage in an artery or vein.

[0039] As shown in FIG.2, medical device system 200 further includes a localization module 205 configured to determine a position of the catheter distal end 234 when disposed within the body of a patient. For example, the localization module 205 may determine a position and / or orientation of the catheter distal end 234 relative to a three-dimensional reference grid. The medical device system 200 may use such localization data as part of a medical procedure to measure patient characteristics and / or to deliver therapy.

[0040] As shown in FIG.2, system 200 may include an imaging module 208. The imaging module 208 may be configured to use one or more x-ray cameras or other sensors to collect imaging data representing patient tissue, (e.g., cardiac, vascular, or other patient tissue) and / orcatheter 230 disposed within a patient (using a technique such as fluoroscopy as one non-limiting example), which may be used for diagnostic or other purposes. In some examples, the medical device system 200 may use captured imaging data along with localization data from the localization module 205 to generate and / or cause the input output interface(s) 202 to display images with a representation of the catheter distal end 234 superimposed over images of patient tissue. Such images may be used by a physician / operator to navigate / position the catheter distal end 234, to perform measurements, and / or to deliver therapy to a patient.

[0041] The localization module 205 may be configured to use a magnetic-based localization system 206 to determine a position and / or orientation of the catheter 230 based on a position of one or more magnetic sensors(s) 237 of the catheter distal end 234 relative to one or more magnetic field(s) as a reference coordinate system. The magnetic sensor(s) 237 may include one or more magnetic coil(s) wrapped around a core material in the catheter distal end 234. In some examples, the magnetic sensor(s) 237 may include solid-state sensors that include one or more magnetic coil(s) printed on a substrate material. Like the electrode(s) 235, the magnetic sensor(s) 237 may be coupled to sensing circuitry through one or more conductor(s) 216 disposed in one or more lumens of the catheter 230.

[0042] FIG. 3 is a diagram showing one example of a medical device system that incorporates a magnetic-based localization system 206 to determine a position of a catheter 230 within a patient. As shown in FIG. 3, the system includes a magnetic field generator 336, which is positioned to generate one or more magnetic field(s) to define a motion box 340 within the patient as shown. As one example, the magnetic field generator 336 may generate magnetic fields arranged in respective X, Y, and Z dimensions. According to such examples, one or more magnetic sensor(s) 237 of the catheter distal end 234 are configured to generate a measurable electrical current responsive to the magnetic field(s) within the motion box 340, which may be used to determine one or more of a three-dimensional position and orientation of the catheter 230 within a patient relative to a reference grid defined by the magnetic field(s).

[0043] The localization module 205 may also, or instead, use an impedance-based localization system 207 to determine a position of the catheter distal end 234 within a patient. According to such examples, the localization module 205 may determine a position of the electrode(s) 235 of the catheter 230 relative to an electric field as a reference coordinate system. For example, the localization module 205 may capture and process signals from the electrode(s) 235 while theelectrode(s) 235 are disposed in one or more controlled electrical field(s) generated by an external source, such as one or more the patch electrodes (not shown) applied to the skin of a patient. As one example, the controlled electric fields may be arranged in respective X, Y, and Z dimensions. According to these examples, the impedance-based localization system 207 may be configured to measure electrical signals received from electrode(s) via the conductor(s) 215, and use the received electrical signals to determine a location of the electrode(s) 235 relative to the controlled electric field(s).

[0044] In some other examples, the localization module 205 may use both a magnetic-based localization system 206 and an impedance-based localization system 207 together to determine a position of the catheter distal end 234. According to these examples, the localization module 205 may correlate a reference grid associated with the magnetic-based localization system 206 and a reference grid associated with the impedance-based localization system 207 to one another to determine a position of the catheter distal end 234 in three-dimensional space. In some examples, system 200 may operate to identify a three-dimensional position of the catheter distal end 234 with greater accuracy using both the magnetic-based localization system 206 and the impedance-based localization system 207 together to determine a position and / or orientation of the catheter 230.

[0045] Some traditional catheter systems may incorporate a guidewire 220 to facilitate introducing the catheter to the body of a patient. The guidewire 220 is a metallic flexible “wire” that includes a guidewire distal end 224 configured to be introduced into the vascular system of a patient and a guidewire proximal end configured to be controlled by a physician or other medical professional to position the guidewire distal end 224 within the patient. The guidewire distal end 224 is configured to extend through a lumen in the catheter 230 and guide the catheter 230 such that the catheter 230 may be advanced to a desired position to sense electrical characteristics and / or delivery therapy to patient tissue.

[0046] As shown in FIG.2, medical device system 200 is uniquely configured to include a guidewire 220 with one or more guidewire electrode(s) 225, which may be arranged at or near a distal end 224 of the guidewire 220. In some examples, the guidewire electrode(s) 225 may be a conductive tip at the distal end 224 of the guidewire 220 that is configured to be advanced within an organ such as an artery or vein as part of a medical procedure. In some examples, the guidewire electrode(s) 225 are formed of a conductive material while other portions of theguidewire 220 other than the electrode(s) are formed of a non-conductive material. In some examples, the guidewire 220 has a smaller diameter than the catheter distal end 234. The guidewire can generally can be more easily steered. In some examples, the guidewire electrode(s) 225 may be smaller than the catheter electrode(s) 235.

[0047] Medical device system 200 is configured to use the electrode(s) 225 of the guidewire 220 to perform one or more measurement and / or to deliver therapy to a patient. For example, medical device system 200 may use the electrode(s) 225 to localize the guidewire 220 and determine a position / orientation of the guidewire 220 by capturing and processing signals from the guidewire electrode(s) 235 while the electrode(s) 235 are disposed in one or more controlled electrical field(s). As described above, the position / orientation of the guidewire 220 may be used by the medical device system 200 to generate and / or display images for use by a physician / operator to navigate the guidewire 220, or for another purpose associated with performing measurements or therapy delivery.

[0048] In some examples, the guidewire electrode(s) 235 may be used, alone or with other sensors (e.g., electrode(s) 235 of catheter 230), to perform measurements. For example, the guidewire electrode(s) 235 may be arranged in contact with or proximity to patient tissue (i.e., cardiac or other vascular tissue) to measure a resistance across the tissue and / or whether the guidewire electrode(s) 235 are in contact with patient tissue. In some examples, the medical device system 200 may use measurements from the guidewire electrode(s) 225 to generate an electrocardiogram waveform for use by a physician / operator. In some examples, the medical device system 200 may use measurements detected from the guidewire electrode(s) 225 directly to generate an electrocardiogram waveform. In other examples, the medical device system 200 may use the guidewire electrode(s) 225 to reduce or eliminate interference for measurements taken by other sensors (e.g., electrode(s) 235 of catheter 230).

[0049] In some examples, medical device system 200 may use the guidewire electrode(s) 225 to deliver therapy to a patient, for example to deliver electrical energy to ablate patient tissue. According to such examples, the guidewire electrode(s) 225 may be used as an anode or a cathode to deliver energy to ablate tissue. For example, the guidewire electrode(s) 235 may be used as an anode while catheter electrode(s) 235 serve as a cathode to deliver ablation therapy. In other examples, the guidewire electrode(s) 225 may be used as a cathode while catheter electrode(s) 235 serve as an anode to deliver energy to ablate tissue.

[0050] FIG. 4 is a block diagram that depicts one example of a medical device system 400 that includes a guidewire 420 with one or more guidewire electrode(s) 425. The system 400 includes a catheter 430 with a catheter tube 431, a catheter proximal end 432, and a catheter distal end 434. The catheter distal end 434 includes electrode(s) 435 arranged to be placed in contact with patient tissue. The catheter 430 is configured to be introduced into the body of a patient by advancing the catheter 430 along a guidewire 420 that extends through a lumen in the catheter tube 431. The catheter electrode(s) 435 are coupled to one or more processor(s) 450 of the medical device system 400 and used to perform measurements and deliver therapy.

[0051] As shown in FIG. 4, the guidewire 420 includes one or more electrode(s) 425 that are communicatively coupled to the processor(s) 450 via one or more conductor(s) 417 that extend through a lumen in the guidewire 420. The electrode(s) 425 may be positioned along a length of the guidewire 420, for example at or near a distal end 424 of the guidewire 420. In some examples the electrode(s) 425 may be arranged at a conductive tip 429 of the guidewire 420 and may serve as an external contact surface of the conductive tip 429 of the guidewire 420.

[0052] The processor(s) 450 may use the electrode(s) 425 to perform measurements and / or to deliver therapy. For example, the processors(s) 450 may receive measurement signals 441 from the electrode(s) 425, and use the measurement signals 441 to diagnose a patient condition, to perform localization to aid in navigation / positioning of the guidewire 420 / catheter 430, to determine an appropriate therapy, or other purpose associated with patient health. As another example, the processor(s) 450 may use the electrode(s) 425 to deliver therapy signals 443 to a patient, for example to deliver therapy signals 443, for example in the form of electrical energy to selectively ablate patient tissue to treat one or more cardiac conditions such as arrhythmia.

[0053] FIG. 5 is a block diagram that depicts one example of a medical device system 500 that uses one or more guidewire electrode(s) 425 to localize (i.e., determine a position and / or orientation) a guidewire 420. The medical system 500 depicted in FIG. 5 is substantially similar to the medical device system 400 depicted in FIG. 4 and includes a catheter 430 with a catheter distal end 434 with one or more electrode(s) 435 coupled to one or more processor(s) 450 and used for performing measurements and / or delivering therapy. The catheter 430 is configured to be advanced along a guidewire 420 that extends through a lumen in the catheter tube 431. The guidewire 420 includes one or more electrode(s) 425 at the distal end 424.

[0054] In the example of FIG. 5, measurement signals 541 from the guidewire electrode(s) 425 are used by the processor(s) 450 for localization. For example, the processor(s) 450 may measure electrical signals from the guidewire electrode(s) 425 caused by one or more externally generated electric field(s) (e.g., generated by one or more patch electrodes as described above) to determine a position and / or orientation of the guidewire 420 in three-dimensional space. In some examples, position and / or orientation information from the guidewire electrode(s) 425 may be used as part of a medical procedure, for example to cause images to be displayed to a physician / operator to assist in navigation / positioning of the guidewire 420 and / or catheter distal end 434.

[0055] In some examples, localization data measured using electrode(s) 425 may be used with other sensed data as part of a medical procedure. For example, guidewire 420 may optionally include one or more magnetic sensor(s) 527 arranged along a length of the guidewire 420 as shown in FIG.5. The magnetic sensor(s) 527 may include one or more magnetic coil(s) wrapped around a core material in the guidewire 420. In some examples, the magnetic sensor(s) 527 may include solid-state sensors that include one or more magnetic coil(s) printed on a substrate material. In some examples, the magnetic sensor(s) 527 may be arranged at or near a distal end 424 of the guidewire 420, as one example at or near the conductive tip 429 at the distal end 424 of the guidewire 420. In some examples, the magnetic sensor(s) 527 may be arranged proximal to the electrode(s) 425. According to these examples, the magnetic sensor(s) 527 may be used by a magnetic-based localization system 206 as depicted in FIG. 2 to generate location data that represents a position of the magnetic sensor(s) 527 relative to one or more externally generated magnetic field(s). According to these examples, medical device system 500 may be configured use localization data from the electrode(s) 425 along with localization data from the magnetic sensor(s) 527 to determine a position and / or orientation of the guidewire 420.

[0056] In some examples, the system 500 may leverage the guidewire magnetic sensor(s) 527 and the guidewire electrode(s) 425 to form a correlation of impedance information in three-dimensional (3D) space with magnetic information in 3D space to compute a transform (which may be referred to as a volumetric pixel, or voxel). Having computed voxels based on the combination of magnetic information and impedance information, other devices having only impedance-based localization capabilities may be associated with particular voxels. In some examples, such a correlation may be used to collect a confidence cloud used to visualize a vein, artery, or other organ.

[0057] In some examples, system 500 may use localization information from the guidewire electrode(s) 425 and / or magnetic sensor(s) 527 to assist with guiding the catheter 430 to a desired position within a patient. For example, the guidewire electrode(s) 425 may be used by system 500 to identify veins. In some examples, using the guidewire electrode(s) 425 and / or magnetic sensor(s) for localization as described may enable system 500 to use flouroscopy or similar systems for imaging less frequently or not at all. which may offer health advantages and / or reduce study times.

[0058] In some examples, the magnetic sensor(s) 527 and / or electrode(s) 425 may be used in combination with other sensor information to determine a relative position of the catheter distal end 434 to the guidewire 420. For example, system 500 may use localization data from electrode(s) 435 and / or magnetic sensor(s) (not shown) of the catheter distal end 434 to determine a position of the catheter distal end 434. The system 500 may also use localization data from electrode(s) 425 and / or magnetic sensor(s) 527 to determine a position of the guidewire 420, specifically a position of the conductive tip 429 of the guidewire 420. According to such examples, the system 500 may be configured to generate an alarm when the catheter distal end 434 is advanced too far relative to the guidewire 420 to reduce a potential for catheter prolapse.

[0059] FIG.6 is a block diagram that depicts one example of medical device system 600 that uses one or more guidewire electrode(s) 425 to measure a resistance of patient tissue. The medical system 600 depicted in FIG. 6 is substantially similar to the medical device systems 400, 500 depicted in FIGS.4 and 5 and includes a catheter 430 with a catheter distal end 434 that includes one or more electrode(s) 435 coupled to one or more processor(s) 450 and used for performing measurements and / or delivering therapy. The catheter 430 is configured to be advanced along a guidewire 420 that extends through a lumen in the catheter tube 431. The guidewire 420 includes one or more guidewire electrode(s) 425 at the distal end 424.

[0060] In the example of FIG.6, processor(s) 450 use measurement signals 641 received from the guidewire electrode(a) 425 to measure an impedance surrounding the guidewire electrode(s) 425 for example to detect whether the guidewire electrode(s) 425 is surrounded by blood or in contact with patient tissue. System 600 may use such measurement signals 641 to note where cardiac or other surfaces are in three-dimensional space.

[0061] In some examples, the processor(s) 450 use measurement signals 641 received from the guidewire electrode(a) 425 to detect changes in resistance, impedance, or other characteristic ofpatient tissue as part of a patient diagnosis or therapy delivery procedure. In some examples, relatively large changes in tissue resistance / impedance may indicate to system 600 that models should be collected, that markers should be placed, and / or that lesions should be formed through the delivery of ablation or other therapy. Various circuit configurations may be utilized to perform tissue impedance / resistance measurements, using guidewire electrode(s) 425 and / or catheter electrodes 435 including three-terminal impedance measurement circuits, two-terminal impedance measurement circuits, and tetra-polar impedance measurements.

[0062] FIG.7 is a block diagram that depicts one example of medical device system 700 that uses one or more guidewire electrode(s) 425 to detect at least part of an electrocardiogram (EGM) waveform. The medical system 700 depicted in FIG. 7 is substantially similar to the medical device systems 400, 500, and 600 depicted in FIGS.4 -6 and includes a catheter 430 with a catheter distal end 434 that includes one or more electrode(s) 435 coupled to one or more processor(s) 450 and used for performing measurements and / or delivering therapy. The catheter 430 is configured to be advanced along a guidewire 420 that extends through a lumen in the catheter tube 431. The guidewire 420 includes one or more guidewire electrode(s) 425 at the distal end 424 of the guidewire 420.

[0063] The EGM waveform may represent electrical activity of the heart and may be generated based on measurement signals 741 received via the catheter electrodes 435 and / or the guidewire electrode(s) 425 alone or in combination with one another. In some examples, as shown in FIG.7, according to examples where the catheter electrode(s) 435 are used to measure the EGM waveform, the guidewire electrode(s) 425 may be used as a unipolar reference to reduce far-field interference on measurement of the EGM waveform from the catheter electrode(s) 435. According to some such examples, the guidewire 420 is configured to be secured in a fixed position relative to the catheter 430. Specifically, the catheter distal end 434 may include a mechanical locking mechanism that allows a position of the guidewire electrode(s) 425 to be fixed relative to the catheter 430 / catheter electrode(s) 435. In some such examples, after being used to guide the catheter distal end 434 to a desired position within the patient, the guidewire 420 may be withdrawn and locked in position with the guidewire electrodes 425 exposed and not in contact with patient tissue. In some examples, with a position of the guidewire electrode(s) 425 fixed, far-field interference detected by the guidewire electrode(s) 425 may be used as a reference to filter out the far-field interference from signals measured by the catheter electrode(s) 435. Accordingly,an impact of far field signals on measurement of the EGM waveform may be reduced or eliminated. In some examples, using the guidewire electrode(s) 425 as a unipolar reference may enable gap detection, mapping and other functions to be performed with greater accuracy than traditional medical device systems.

[0064] In some examples, the guidewire electrode(s) 435 may be used to detect an EGM waveform. According to such examples, the catheter 430 may be configured such that a position of the guidewire 420 may be fixed relative to patient tissue and used to detect the EGM waveform.

[0065] FIG.8 is a block diagram that depicts one example of medical device system 800 that uses one or more guidewire electrode(s) 425 to detect deliver therapy to a patient. The medical system 800 depicted in FIG. 8 is substantially similar to the medical device systems 400, 500, 600, and 700 depicted in FIGS. 4-7 and includes a catheter 430 with a catheter distal end 434 that includes one or more electrode(s) 435 coupled to one or more processor(s) 450 and used for performing measurements and / or delivering therapy. The catheter 430 is configured to be advanced along a guidewire 420 that extends through a lumen in the catheter tube 431. The guidewire 420 includes one or more electrode(s) 425 at the distal end 424.

[0066] According to the example of FIG. 8, processor(s) 450 are configured to cause therapy signals 743 in the form of electrical energy to be delivered to patient tissue using the guidewire electrode(s) 425 alone or in combination with catheter electrode(s) 435. For example, where guidewire 420 includes multiple electrodes along a length of the guidewire 420, a first guidewire electrode may be used as a cathode, and a second guidewire electrode distanced from the first guidewire electrode may be used as an anode to deliver energy for therapy purposes. In some examples, guidewire electrodes 425 may be used as both an anode and a cathode to deliver alternating current and / or high frequency therapy to a patient.

[0067] In other examples, the guidewire electrode(s) 425 may be used with catheter electode(s) 435 to deliver therapy. For example, the guidewire electrode(s) 425 may be used as an anode and the catheter electrode(s) 435 may be used as a cathode to delivery therapy. In other examples, the guidewire electrode(s) 425 may be used as a cathode and the catheter electrode(s) 435 may be used as an anode to delivery therapy. In some examples where guidewire 420 includes multiple electrodes 425, the multiple electrodes may be used as an anode, a cathode, or both an anode or cathode with or without catheter electrode(s) 435 used as an anode or cathode.

[0068] In some examples, using the guidewire electrode(s) 425 as an anode, a cathode, or both for therapy delivery may enable placement of the anode / cathode more deeply into a vein, artery, or other organ. In some examples, since the guidewire electrode(s) 425 are more movable relative to the catheter electrode(s) 435, system 800 be operable to form more uniform lesions with fewer potential gaps than traditional systems that use catheter electrode(s) 435 alone for therapy delivery. In some examples, the guidewire electrode(s) 425 may be a conductive tip 429 of the guidewire 420, and a remainder of the guidewire 420 includes a non-conductive coating or material.

[0069] In some examples, medical device system 800 may use guidewire electrode(s) 425 as part of a therapy procedure to modify shadow lesions. In some examples, medical device system 800 may use the guidewire electrode(s) 425 to direct a lesion morphology, for example by of moving the guidewire electrode(s) 425 as an anode / cathode to different positions within of a vein, artery, or other organ without moving the catheter 430 (i.e., catheter electrode(s) 435 used as a cathode / anode).

[0070] FIG. 9 is a flow diagram that depicts one example of a method of using a guidewire 420 of a catheter 430. As shown in FIG. 9, at 901, the method includes advancing a guidewire 420 with a proximal end 422 configured to be controlled by an operator to advance a distal end 424 of the guidewire 420 that includes one or more guidewire electrode(s) 425. The guidewire 420 may extend through a catheter tube 131 of the catheter 430 such that a catheter distal end 434 may be advanced to a desired position along the guidewire 420 within a patient. In some examples, the guidewire electrode(s) 425 are arranged at or near a distal end 424 of the guidewire 220. In some examples, the guidewire electrode(s) 425 comprises a conductive tip 429 of the guidewire 420.

[0071] As shown in FIG. 9, at 902, the method further includes using the guidewire electrode(s) 425 to perform one or more of measurements and therapy delivery. For example, the method may include using the guidewire electrode(s) 425 to determine a position and / or orientation of the distal end of the guidewire 420. In some examples, the guidewire electrode(s) 425 alone may be used to determine a position and / or orientation of the guidewire 420. In other examples, the guidewire electrode(s) 425 may be used with other sensors to determine a position of the guidewire 420. For example, the method may include using one or more magnetic sensor(s) 527 at the distal end 424 of the guidewire 420 along with the guidewire electrode(s) 425 to determine a correlation of magnetic and impedance information in three-dimensional (3D) space.

[0072] In some examples, the method further includes using the guidewire electrode(s) 425 to determine whether the guidewire 420, e.g., the conductive tip 429 of the guidewire 420, is in contact with patient tissue. In some examples, the method further includes using the guidewire electrode(s) 425 to measure one or more changes in resistance of patient tissue. In some examples, the method further includes using the guidewire electrode(s) 425 as an anode or a cathode to deliver therapy to tissue. For example, the method may include using the guidewire electrode(s) 425 as an anode, and catheter electrode(s) 435 as an anode. As another example, the method includes using the guidewire electrode(s) 425 as a cathode and the catheter electrode(s) 435 as an anode.

[0073] In some examples, the method further includes using the guidewire electrode(s) 425 to measure an electrocardiogram (EGM) signal. For example, catheter electrode(s) 435 may be used to measure the EGM signal, and the guidewire electrode(s) 425 may be used as a signal reference to detect far- field interference, which may be used to minimize and / or eliminate an impact of the far-field interference on the EGM signal detected via the catheter electrode(s) 435. In other examples, the method includes using the guidewire electrode(s) 425 to directly measure an electrocardiogram signal. In some examples, the method further includes securing a position of the catheter distal end 434 relative to the guidewire 420 to secure the guidewire electrode(s) 425 distanced from the catheter electrode(s) 435 for use to remove far-field signals from measurements detected by the catheter electrode(s) 435. In some examples, the method includes using the guidewire electrode(s) 425 as a conductive tip 429 of the guidewire 420. In some examples, the method includes using one or more conductor(s) 417 of the guidewire 420 to perform measurements and / or deliver therapy using the guidewire electrode(s) 425.

[0074] The following relates to numbered clauses of the disclosure.

[0075] Clause 1. A medical device system, comprising: a guidewire with a proximal end configured to be controlled by an operator to advance a distal end of the guidewire; at least one guidewire electrode positioned at the distal end of the guidewire; and a processor coupled to the at least one guidewire electrode and configured to perform one or more of measurements and therapy delivery using the at least one guidewire electrode.

[0076] Clause 2. The catheter device of clause 1, wherein the processor is configured to use the at least one guidewire electrode to determine a position of the distal end of the guidewire.

[0077] Clause 3. The catheter device of any of clauses 1 and 2, further comprising a magnetic sensor positioned at the distal end of the guidewire, wherein the processor is configured to use the magnetic sensor in combination with the guidewire electrode to determine a correlation of magnetic and impedance information in 3D space.

[0078] Clause 4. The catheter device of any of clauses 1-3, wherein the processor is configured to use the at least one guidewire electrode to determine whether the guidewire is in contact with tissue.

[0079] Clause 5. The catheter device of any of clauses 1-4, wherein the processor is configured to use the at least one guidewire electrode to measure changes in tissue resistance and / or impedance.

[0080] Clause 6. The catheter device of any of clauses 1-5, wherein the processor is configured to use the at least one guidewire electrode as an anode or a cathode to deliver therapy to tissue.

[0081] Clause 7. The catheter device of any of clauses 1-6, wherein the processor is configured to measure electrical characteristics of tissue using the at least one guidewire electrode as a unipolar reference to remove far-field signals from signals detected by at least one catheter electrode.

[0082] Clause 8. The catheter device of any of clauses 1-7, wherein the catheter device includes a catheter, and the guidewire is configured to be secured in a fixed position relative to the catheter.

[0083] Clause 9. The catheter device of any of clauses 1-8, wherein the at least one guidewire electrode comprises a conductive tip at the distal end of the guidewire.

[0084] Clause 10. The catheter device of any of clauses 1-9, further comprising one or more conductors in the guidewire that couple the at least one guidewire electrode to the processor at the proximal end of the guidewire.

[0085] Clause 11. A method for using a catheter device, comprising: advancing a guidewire with a proximal end configured to be controlled by an operator to advance a distal end of the guidewire that includes at least one guidewire electrode; and using the at least one guidewire electrode to perform one or more of measurements and therapy delivery.

[0086] Clause 12. The method of clause 11, further comprising: using the at least one guidewire electrode of the guidewire to determine a position of the distal end of the guidewire.

[0087] Clause 13. The method of clause any of clauses 11-12, further comprising: usingamagnetic sensor positioned at the distal end of the guidewire in combination with the at least one guidewire electrode to determine a correlation of magnetic and impedance information in 3D space.

[0088] Clause 14. The method of any of clauses 11-13, further comprising: using the at least one guidewire electrode to determine whether the guidewire is in contact with patient tissue.

[0089] Clause 15. The method of any of clauses 11-14, further comprising: using the at least one guidewire electrode to measure changes in tissue resistance and / or impedance.

[0090] Clause 16. The method of clause any of clauses 11-15, further comprising: using the at least one guidewire electrode as an anode or a cathode to deliver therapy to tissue.

[0091] Clause 17. The method of any of clauses 11-16, further comprising: measuring electrical characteristics of tissue using the at least one guidewire electrode as a unipolar reference to remove far-field signals from signals detected by at least one catheter electrode.

[0092] Clause 18. A guidewire for use with a medical device system, comprising: a guidewire proximal end; a guidewire distal end; and at least one guidewire electrode positioned along a length of the guidewire and used to perform one or more measurements or delivery therapy to a patient.

[0093] Clause 19. The guidewire of clause 18, wherein the at least one guidewire electrode is configured to be used to perform measurement to determine one or more of; a position of the guidewire; a resistance and / or impedance of patient tissue; whether the at least one guidewire electrode is in contact with patient tissue; and an electrocardiogram waveform.

[0094] Clause 20. The guidewire of clause any of clauses 18-19, wherein the at least one guidewire electrode is configured to be used as one or more of an anode and cathode to deliver ablation therapy to a patient.

[0095] Clause 21. A computer-readable medium storing instructions that, when executed by a processor, cause the processor to: use at least one guidewire electrode at the distal end of a guidewire to perform measurements.

[0096] Clause 22. The computer-readable medium of clause 21, wherein the instructions further cause the processor to use the at least one guidewire electrode to determine the position of the distal end of the guidewire.

[0097] Clause 23. The computer-readable medium of any of clauses 21-22, wherein the instructions further cause the processor to use a magnetic sensor positioned at the distal end of the guidewire in combination with the at least one guidewire electrode to determine a correlation of magnetic and impedance information in 3D space.

[0098] Clause 24. The computer-readable medium of any of clauses 21-25, wherein the instructions further cause the processor to measure electrical characteristics of tissue using the atleast one guidewire electrode as a unipolar reference to remove far-field signals from signals detected by at least one catheter electrode.

[0099] While this invention has been described with reference to illustrative examples, this description is not intended to be construed in a limiting sense. Various modifications and combinations will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications.

Claims

CLAIMS:

1. A medical device system, comprising:a guidewire with a proximal end configured to be controlled by an operator to advance a distal end of the guidewire;at least one guidewire electrode positioned at the distal end of the guidewire; and a processor coupled to the at least one guidewire electrode and configured to perform one or more of measurements and therapy delivery using the at least one guidewire electrode.

2. The catheter device of claim 1, wherein the processor is configured to use the at least one guidewire electrode to determine a position of the distal end of the guidewire.

3. The catheter device of claim 1 , further comprising a magnetic sensor positioned at the distal end of the guidewire, wherein the processor is configured to use the magnetic sensor in combination with the guidewire electrode to determine a correlation of magnetic and impedance information in 3D space.

4. The catheter device of claim 1, wherein the processor is configured to use the at least one guidewire electrode to determine whether the guidewire is in contact with tissue.

5. The catheter device of claim 1, wherein the processor is configured to use the at least one guidewire electrode to measure changes in tissue resistance and / or impedance.

6. The catheter device of claim 1, wherein the processor is configured to use the at least one guidewire electrode as one or both of an anode and a cathode to deliver therapy to tissue.

7. The catheter device of claim 1, wherein the processor is configured to measure electrical characteristics of tissue using the at least one guidewire electrode as a unipolar reference to remove far-field signals from signals detected by at least one catheter electrode.

8. The catheter device of claim 1, wherein the catheter device includes a catheter, and the guidewire is configured to be secured in a fixed position relative to the catheter.

9. The catheter device of claim 1, wherein the at least one guidewire electrode comprises a conductive tip at the distal end of the guidewire.

10. The catheter device of claim 1 , further comprising one or more conductors in the guidewire that couple the at least one guidewire electrode to the processor at the proximal end of the guidewire.

11. A method for using a catheter device, comprising:advancing a guidewire with a proximal end configured to be controlled by an operator to advance a distal end of the guidewire that includes at least one guidewire electrode; and using the at least one guidewire electrode to perform one or more of measurements and therapy delivery.

12. The method of claim 11, further comprising:using the at least one guidewire electrode of the guidewire to determine a position of the distal end of the guidewire.

13. The method of claim 11 , further comprising:using a magnetic sensor positioned at the distal end of the guidewire in combination with the at least one guidewire electrode to determine a correlation of magnetic and impedance information in 3D space.

14. The method of claim 11, further comprising:using the at least one guidewire electrode to determine whether the guidewire is in contact with patient tissue.

15. The method of claim 11, further comprising:using the at least one guidewire electrode to measure changes in tissue resistance and / or impedance.

16. The method of claim 11, further comprising:using the at least one guidewire electrode as one or both of an anode and a cathode to deliver therapy to tissue.

17. The method of claim 11, further comprising:measuring electrical characteristics of tissue using the at least one guidewire electrode as a unipolar reference to remove far-field signals from signals detected by at least one catheter electrode.

18. A guidewire for use with a medical device system, comprising:a guidewire proximal end;a guidewire distal end; andat least one guidewire electrode positioned along a length of the guidewire and used to perform one or more of measurements and therapy delivery.

19. The guidewire of claim 18, wherein the at least one guidewire electrode is configured to be used to perform measurement to determine one or more of:a position of the guidewire;a resistance and / or impedance of patient tissue;whether the at least one guidewire electrode is in contact with patient tissue; and an electrocardiogram waveform.

20. The guidewire of claim 19, wherein the at least one guidewire electrode is configured to be used as one or both of an anode and a cathode to deliver ablation therapy to a patient.

Images