CN116458989A

CN116458989A - Systems and methods for forming single spiral electrode assemblies of spherical baskets for improved tissue contact and current delivery

Info

Publication number: CN116458989A
Application number: CN202310110754.1A
Authority: CN
Inventors: K·M·奥卡斯基; K·达塔; A·巴; T·阮
Original assignee: Biosense Webster Israel Ltd
Current assignee: Biosense Webster Israel Ltd
Priority date: 2022-01-20
Filing date: 2023-01-19
Publication date: 2023-07-21

Abstract

The disclosed technology includes a medical probe including a tubular shaft having a proximal end and a distal end. The tubular shaft may extend along a longitudinal axis. The medical probe may include an expandable basket assembly proximate the distal end of the tubular shaft. The expandable basket assembly may include a single spine including a resilient material extending generally linearly along the longitudinal axis in a collapsed form and forming a helical member defining a generally spherical outer periphery in an expanded form. One or more electrodes may be coupled to the single ridge. Each electrode may include a lumen offset relative to a centroid of the electrode such that the single ridge extends through the lumen of each of the one or more electrodes.

Description

Systems and methods for forming single spiral electrode assemblies of spherical baskets for improved tissue contact and current delivery

Cross Reference to Related Applications

The present application claims the benefit of priority from U.S. c. ≡119, U.S. provisional patent application 63/301,096, filed previously at 20, 1, 2022, the entire contents of which are hereby incorporated by reference as if fully set forth herein.

Technical Field

The present invention relates generally to medical devices, and in particular to catheters having electrodes, and further, but not exclusively, to catheters suitable for inducing irreversible electroporation (IRE) of cardiac tissue.

Background

Arrhythmia, such as Atrial Fibrillation (AF), may occur when areas of heart tissue abnormally conduct electrical signals to adjacent tissue. This can disrupt the normal cardiac cycle and lead to arrhythmia. Certain protocols are used to treat cardiac arrhythmias, including surgically disturbing the source of the signals responsible for the arrhythmia and disturbing the conduction pathways for such signals. By selectively ablating cardiac tissue by applying energy through the catheter, it is sometimes possible to stop or alter the propagation of unwanted electrical signals from one portion of the heart to another.

Many current ablation methods in the art tend to utilize Radio Frequency (RF) electrical energy to heat tissue. RF ablation may have some rare drawbacks due to the skill of the operator, such as an increased risk of thermal cell damage, which may lead to charring of tissue, burns, steam pops, phrenic nerve paralysis, pulmonary vein stenosis, and esophageal fistulae. Cryoablation is an alternative to RF ablation, which gradually reduces some of the thermal risks associated with RF ablation, but may cause tissue damage due to the very low temperature nature of such devices. However, manipulating a cryoablation device and selectively applying cryoablation is generally more challenging than RF ablation; thus, cryoablation is not feasible in certain anatomical geometries that may be reached by an electrical ablation device.

Some ablation methods use irreversible electroporation (IRE) to ablate cardiac tissue using non-thermal ablation methods. IRE delivers short pulses of high pressure to the tissue and produces unrecoverable cell membrane permeabilization. The use of multi-electrode catheters to deliver IRE energy to tissue has previously been proposed in the patent literature. Examples of systems and devices configured for IRE ablation are disclosed in U.S. patent publications 2021/0169550A1, 2021/0169567A1, 2021/0169568A1, 2021/0161592A1, 2021/0196372A1, 2021/0177503A1 and 2021/0186604A1, each of which is incorporated by reference in its entirety into this application as if fully set forth and attached in the appendix of priority application U.S. Pat. No. 63/301,096.

Areas of cardiac tissue may be mapped by the catheter to identify abnormal electrical signals. Ablation may be performed using the same or different catheters. Some example catheters include a plurality of ridges on which electrodes are disposed. The electrodes are typically attached to the ridges and secured in place by brazing, welding, or using an adhesive. Further, the plurality of linear ridges are typically assembled together by attaching both ends of the linear ridges to a tubular shaft (e.g., a push tube) to form a ballbasket. However, due to the smaller size of the ridges and electrodes, adhering the electrodes to the ridges, and then forming the ball basket from multiple linear ridges can be a difficult task, increasing manufacturing time and cost, and increasing the chance of failure of the electrodes due to improper bonding or misalignment. Accordingly, what is needed are devices and methods of forming improved basket assemblies that can position electrodes in place when in an expanded state, while also reducing the overall manufacturing complexity of the basket assemblies.

Disclosure of Invention

The present invention provides various embodiments of medical probes, including certain methods related thereto. In one exemplary embodiment (among many), the medical probe includes a tubular shaft having a proximal end and a distal end. The tubular shaft may extend along a longitudinal axis. The medical probe may include an expandable basket assembly proximate the distal end of the tubular shaft. The expandable basket assembly may include a single spine including a resilient material extending generally linearly along the longitudinal axis in a collapsed form and forming a helical member defining a generally spherical outer periphery in an expanded form. One or more electrodes may be coupled to the single ridge. Each electrode may include a lumen offset relative to a centroid of the electrode such that the single ridge extends through the lumen of each of the one or more electrodes.

Drawings

FIG. 1 is a schematic illustration of a medical system including a medical probe having a distal end including a basket assembly with electrodes according to an embodiment of the present invention;

FIG. 2 is a schematic illustration showing a perspective view of a medical probe in an expanded form according to an embodiment of the invention;

Fig. 3 is a schematic illustration showing an exploded side view of a medical probe in an expanded form in accordance with the disclosed technology.

FIG. 4 is a schematic illustration showing a side view of a medical probe in a collapsed form in accordance with the disclosed technology;

FIG. 5 is a schematic illustration of a method of forming ridges from a planar sheet of elastomeric material in accordance with the disclosed technology;

FIG. 6 is a schematic illustration of a method of forming ridges from a cylindrical hollow tube of elastomeric material in accordance with the disclosed technology;

fig. 7A-7J are schematic illustrations showing perspective views of various exemplary electrodes in accordance with the disclosed technology;

fig. 8A and 8B are schematic illustrations showing various insulating sheaths of a given medical device according to embodiments of the invention;

FIGS. 9A and 9B are schematic illustrations showing cross-sectional views of a given line of a medical probe according to an embodiment of the invention;

FIG. 10 is a flow chart of a method of assembling a basket assembly according to an embodiment of the present invention;

FIG. 11 is a flow chart of another method of assembling a basket assembly according to an embodiment of the present invention;

FIG. 12 is a flow chart of another method of assembling a basket assembly according to an embodiment of the present invention.

Detailed Description

The following detailed description should be read with reference to the drawings, in which like elements in different drawings are numbered identically. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. The detailed description illustrates by way of example, and not by way of limitation, the principles of the invention. This description will clearly enable one skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.

As used herein, the term "about" or "approximately" for any numerical value or range indicates a suitable dimensional tolerance that allows a collection of parts or components to achieve the intended purpose thereof as described herein. More specifically, "about" or "approximately" may refer to a range of values of ±20% of the recited values, for example "about 90%" may refer to a range of values of 71% to 110%.

As used herein, the term "proximal" refers to a location closer to an operator or physician, and "distal" refers to a location further from an operator or physician.

As discussed herein, the vasculature of a "patient," "recipient," "user," and "subject" may be the vasculature of a human or any animal. It should be understood that the animal may be of any suitable type including, but not limited to, a mammal, a veterinary animal, a livestock animal or a companion animal, and the like. For example, the animal may be a laboratory animal (e.g., rat, dog, pig, monkey, etc.) specifically selected to have certain characteristics similar to humans. It should be appreciated that the subject may be, for example, any suitable human patient.

As discussed herein, an "operator" may include a doctor, surgeon, technician, scientist, or any other individual or delivery meter device associated with delivering a multi-electrode catheter for treating drug refractory atrial fibrillation to a subject.

As discussed herein, the term "ablation" when referring to the devices and corresponding systems of the present disclosure refers to components and structural features configured to reduce or prevent the generation of unstable cardiac signals in cells by utilizing non-thermal energy, such as irreversible electroporation (IRE), interchangeably referred to in the present disclosure as Pulsed Electric Field (PEF) and Pulsed Field Ablation (PFA). "ablation" as used throughout the present disclosure, when referring to the devices and corresponding systems of the present disclosure, refers to non-thermal ablation of cardiac tissue for certain conditions, including, but not limited to, arrhythmia, atrial flutter ablation, pulmonary vein isolation, supraventricular tachycardia ablation, and ventricular tachycardia ablation. The term "ablation" also includes known methods, devices and systems that implement various forms of body tissue ablation as understood by those skilled in the relevant art.

As discussed herein, the terms "bipolar" and "monopolar" when used in reference to an ablation scheme describe an ablation scheme that differs in terms of current path and electric field distribution. "bipolar" refers to an ablation protocol that utilizes a current path between two electrodes, both of which are positioned at a treatment site; the current density and the current flux density at each of the two electrodes are typically approximately equal. "monopolar" refers to an ablation procedure utilizing a current path between two electrodes, where one electrode having a high current density and a high electrical flux density is positioned at the treatment site and a second electrode having a relatively lower current density and a lower electrical flux density is positioned away from the treatment site.

As discussed herein, the terms "biphasic pulse" and "monophasic pulse" refer to the corresponding electrical signals. A "biphasic pulse" refers to an electrical signal having a positive voltage phase pulse (referred to herein as the "positive phase") and a negative voltage phase pulse (referred to herein as the "negative phase"). "monophasic pulse" refers to an electrical signal having only a positive phase or only a negative phase. Preferably, the system providing biphasic pulses is configured to prevent the application of a direct current voltage (DC) to the patient. For example, the average voltage of the biphasic pulse may be zero volts relative to ground or other common reference voltage. Additionally or alternatively, the system may include a capacitor or other protective component. Voltage amplitudes of biphasic and/or monophasic pulses are described herein, it being understood that the expressed voltage amplitudes are absolute values of the approximate peak amplitudes of each of the positive voltage phase and/or the negative voltage phase. Each phase of the biphasic pulse and the monophasic pulse preferably has a square shape with a substantially constant voltage amplitude during a substantial portion of the phase duration. The phases of the biphasic pulse are separated in time by an inter-phase delay. The inter-phase delay duration is preferably less than or approximately equal to the duration of the phase of the biphasic pulse. The inter-phase delay duration is more preferably about 25% of the duration of the phase of the biphasic pulse.

As discussed herein, the terms "tubular" and "tube" are to be understood in a broad sense and are not limited to structures that are right circular cylinders or that are entirely circumferential in cross-section or have a uniform cross-section throughout their length. For example, the tubular structure is generally shown as a substantially right circular cylinder structure. However, the tubular structure may have a tapered or curved outer surface without departing from the scope of the present disclosure.

As used herein, the term "temperature rating" is defined as the maximum continuous temperature that a component can withstand during its lifetime without causing thermal damage such as melting or thermal degradation (e.g., charring and chipping) of the component.

The present disclosure relates to systems, methods, or uses and devices utilizing an end effector having electrodes attached to ridges. The exemplary systems, methods, and devices of the present invention may be particularly useful for IRE ablation of cardiac tissue to treat cardiac arrhythmias. Ablation energy is typically provided to the heart tissue by an end portion of the catheter that can deliver ablation energy along the tissue to be ablated. Some example catheters include a three-dimensional structure at the tip portion and are configured to apply ablation energy from various electrodes positioned on the three-dimensional structure. Fluoroscopy may be used to visualize the ablation procedure in combination with such exemplary catheters.

Cardiac tissue ablation using thermal techniques such as Radio Frequency (RF) energy and cryoablation to correct for a malfunctioning heart is a well-known procedure. Typically, for successful ablation using thermal techniques, the cardiac electrode potentials need to be measured at various locations in the myocardium. Furthermore, temperature measurements during ablation provide data that enables ablation efficacy. Typically, for ablation protocols using thermal ablation, electrode potential and temperature are measured before, during, and after the actual ablation.

RF methods may have risks that may lead to charring of tissue, burns, steam bursts, phrenic nerve paralysis, pulmonary vein stenosis, and esophageal fistulae. Cryoablation is an alternative to RF ablation, which may reduce some of the thermal risks associated with RF ablation. However, manipulating a cryoablation device and selectively applying cryoablation is generally more challenging than RF ablation; thus, cryoablation is not feasible in certain anatomical geometries that may be reached by an electrical ablation device.

IRE as discussed in this disclosure is a non-thermal cell death technique that may be used for atrial arrhythmia ablation. To ablate using IRE/PEF, biphasic voltage pulses are applied to disrupt the cellular structure of the myocardium. The biphasic pulse is non-sinusoidal and can be tuned to target cells based on the electrophysiology of the cells. In contrast, to ablate using RF, a sinusoidal voltage waveform is applied to generate heat at the treatment region, heating all cells indiscriminately in the treatment region. Thus, IRE has the ability to avoid adjacent heat sensitive structures or tissue, which would be beneficial in reducing the possible complications known to be affected by ablation or separation modalities. In addition or alternatively, monophasic pulses may be used.

Electroporation can be induced by applying a pulsed electric field across the biological cells to cause reversible (temporary) or irreversible (permanent) creation of pores in the cell membrane. Upon application of a pulsed electric field, the cell has a transmembrane electrostatic potential that rises above the static potential. Electroporation is reversible when the transmembrane electrostatic potential remains below the threshold potential, meaning that the pores can close when the applied pulsed electric field is removed and the cells can repair and survive themselves. If the transmembrane electrostatic potential rises above the threshold potential, electroporation is irreversible and the cell becomes permanently permeable. Thus, cells die from a loss of homeostasis, typically from programmed cell death or apoptosis, which is believed to leave less scar tissue than other modes of ablation. Typically, different types of cells have different threshold potentials. For example, cardiac cells have a threshold potential of about 500V/cm, whereas for bone, the threshold potential is 3000V/cm. These differences in threshold potential allow IRE to selectively target tissue based on the threshold potential.

The solutions of the present disclosure include systems and methods for applying electrical signals from catheter electrodes positioned near myocardial tissue, preferably by applying a pulsed electric field effective to induce electroporation in myocardial tissue. The systems and methods can effectively ablate targeted tissue by inducing irreversible electroporation. In some examples, the systems and methods are effective to induce reversible electroporation as part of a diagnostic procedure. Reversible electroporation occurs when the electricity applied with the electrodes is below the electric field threshold of the target tissue that allows cell repair. Reversible electroporation does not kill cells, but allows the physician to view the effect of reversible electroporation on the electrical activation signal near the target site. Exemplary systems and methods for reversible electroporation are disclosed in U.S. patent publication 2021/0162210, which is incorporated by reference in its entirety as if fully set forth and set forth in the appendix of priority application U.S. 63/301,096.

The pulsed electric field and its effectiveness in inducing reversible and/or irreversible electroporation may be affected by the physical parameters of the system and the biphasic pulse parameters of the electrical signal. Physical parameters may include electrode contact area, electrode spacing, electrode geometry, and the like. Examples presented herein generally include physical parameters suitable for effectively inducing reversible and/or irreversible electroporation. Biphasic pulse parameters of an electrical signal may include voltage amplitude, pulse duration, pulse-to-pulse delay, inter-pulse delay, total applied time, delivered energy, and the like. In some examples, parameters of the electrical signal may be adjusted to induce both reversible and irreversible electroporation given the same physical parameters. Examples of various ablation systems and methods including IRE are provided in U.S. patent publications 2021/0169550A1, 2021/0169567A1, 2021/0169568A1, 2021/0161592A1, 2021/0196372A1, 2021/0177503A1 and 2021/0186604A1, each of which is incorporated by reference in its entirety into this application as if fully set forth and attached in the appendix of priority application U.S. Pat. No. 63/301,096.

To deliver Pulsed Field Ablation (PFA) in an IRE (irreversible electroporation) procedure, the surface area of the electrode in contact with the tissue being ablated should be sufficiently large. As described below, the medical probe includes a tubular shaft having a proximal end and a distal end, and a basket assembly located at the distal end of the tubular shaft. The basket assembly includes a spine and a plurality of electrode assemblies. When in the expanded form, the ridges may form a helical member defining a generally spherical outer periphery.

Fig. 1 is a schematic illustration of a medical system 20 including a medical probe 22 and a console 24 according to an embodiment of the present invention. Medical system 20 may be based on, for example, a system produced by Biosense Webster inc (31 Technology Drive,Suite 200,Irvine,CA 92618 USA)The system. In the embodiments described below, the medical probe 22 may be used for diagnostic or therapeutic treatment, such as for performing an ablation procedure in the heart 26 of the patient 28. Alternatively, the medical probe 22 may be used for other therapeutic and/or diagnostic purposes in the heart or other body organs, mutatis mutandis.

The medical probe 22 includes a flexible insertion tube 30 and a handle 32 coupled to a proximal end of the insertion tube. During a medical procedure, a medical professional 34 may insert the probe 22 through the vascular system of the patient 28 such that the distal end 36 of the medical probe enters a body cavity, such as a chamber of the heart 26. Upon entry of distal end 36 into the chamber of heart 26, medical professional 34 may deploy basket assembly 38 adjacent distal end 36 of medical probe 22. The basket assembly 38 may include a plurality of electrodes 40 attached to a plurality of ridges, as described below with reference to fig. 2. To begin performing a medical procedure, such as irreversible electroporation (IRE) ablation, the medical professional 34 can manipulate the handle 32 to position the distal end 36 such that the electrode 40 engages the cardiac tissue at the desired location or locations. Upon positioning distal end 36 such that electrode 40 engages heart tissue, medical professional 34 can activate medical probe 22 such that electrode 40 delivers an electrical pulse to perform IRE ablation.

The medical probe 22 may include an introducer sheath including the flexible insertion tube 30 and the handle 32 and a treatment catheter including the basket assembly 38, the electrode 40, and the tubular shaft 84 (see fig. 2-4). The treatment catheter is translated through the introducer sheath such that basket assembly 38 is positioned within heart 26. The distal end 36 of the medical probe 22 corresponds to the distal end of the introducer sheath when the basket assembly 38 is received within the flexible insertion tube 30, and the distal end 36 of the medical probe 22 corresponds to the distal end of the basket assembly 38 when the basket assembly 38 extends from the distal end of the introducer sheath. Alternatively, the medical probe 22 may be configured to include a second handle on the treatment catheter and other features as would be understood by one of ordinary skill in the relevant art.

In the configuration shown in fig. 1, the console 24 is connected by a cable 42 to a body surface electrode that typically includes an adhesive skin patch 44 attached to the patient 28. The console 24 includes a processor 46 that, in conjunction with a tracking module 48, determines the position coordinates of the distal end 36 within the heart 26. The position coordinates may be determined based on electromagnetic position sensor output signals provided from the distal portion of the catheter when the generated magnetic field is present. Additionally or alternatively, the location coordinates may be based on impedance and/or current measured between the adhesive skin patch 44 and the electrode 40 attached to the basket assembly 38. In addition to functioning as a position sensor during a medical procedure, the electrode 40 may perform other tasks, such as ablating tissue in the heart.

As described above, the processor 46 may be coupled with the tracking module 48 to determine the location coordinates of the distal end 36 within the heart 26 based on the impedance and/or current measured between the adhesive skin patch 44 and the electrode 40. Such determination is typically after a calibration procedure has been performed that correlates the impedance or current with the known position of the distal end. While the embodiments presented herein describe electrodes 40 that are preferably configured to deliver IRE ablation energy to tissue in heart 26, it is considered to be within the spirit and scope of the present invention to configure electrodes 40 to deliver any other type of ablation energy to tissue in any body cavity. Furthermore, while described in the context of electrodes 40 configured to deliver IRE ablation energy to tissue in heart 26, those skilled in the art will appreciate that the disclosed techniques may be applicable to electrodes used to map and/or determine various characteristics of an organ or other portion of the body of patient 28.

The processor 46 may include real-time noise reduction circuitry 50, typically configured as a Field Programmable Gate Array (FPGA), and analog-to-digital (a/D) signal conversion integrated circuitry 52. The processor may be programmed to execute one or more algorithms and use the characteristics of circuitry 50 and 52 and the modules to enable the medical professional 34 to perform an IRE ablation procedure.

The console 24 also includes an input/output (I/O) communication interface 54 that enables the console 24 to communicate signals from and/or to the electrode 40 and the adhesive skin patch 44. In the configuration shown in fig. 1, console 24 also includes IRE ablation module 56 and switching module 58.

IRE ablation module 56 is configured to generate IRE pulses having peak power in the range of tens of kilowatts. In some examples, electrode 40 is configured to deliver an electrical pulse having a peak voltage of at least 900 volts (V). Medical system 20 performs IRE ablation by delivering IRE pulses to electrodes 40. Preferably, medical system 20 delivers biphasic pulses between electrodes 40 on the ridges. Additionally or alternatively, medical system 20 delivers monophasic pulses between at least one of electrodes 40 and the skin patch.

The system 20 may supply irrigation fluid (e.g., saline solution) to the distal end 36 and to the electrode 40 via a channel (not shown) in the tubular shaft 84 (see fig. 2-4). Irrigation is sometimes used to reduce clot formation, stagnant blood flow, or even reduce the heat generated by ablation via the electrodes. Additionally or alternatively, the irrigation fluid may be supplied through the flexible insertion tube 30. The console 24 includes a flushing module 60 to monitor and control flushing parameters such as pressure and temperature of the flushing fluid. It is noted that while the exemplary embodiment of the medical probe is preferably for IRE or PFA, it is also within the scope of the present invention to use the medical probe alone for RF ablation only (monopolar mode or bipolar mode with external ground electrode), or sequentially (some electrodes in IRE mode and other electrodes in RF mode) or simultaneously (electrode set in IRE mode and other electrodes in RF mode) in combination with IRE ablation and RF ablation.

Based on the signals received from the electrode 40 and/or the adhesive skin patch 44, the processor 46 may generate an electroanatomical map 62 showing the position of the distal end 36 within the patient. During a procedure, the processor 46 may present the map 62 to the medical professional 34 on the display 64 and store data representing the electroanatomical map in the memory 66. Memory 66 may include any suitable volatile memory and/or nonvolatile memory, such as random access memory or a hard disk drive.

In some embodiments, medical professional 34 can manipulate map 62 using one or more input devices 68. In alternative embodiments, display 64 may include a touch screen that may be configured to accept input from medical professional 34 in addition to presenting map 62.

Fig. 2 is a schematic illustration showing a perspective view of a medical probe 22 having a basket assembly 38 in an expanded form when unconstrained, such as by being pushed out of an insertion tube lumen 80 at the distal end 36 of the insertion tube 30. The medical probe 22 shown in fig. 2 lacks the introducer sheath shown in fig. 1. Fig. 3 is an exploded view of the medical probe 22 and basket assembly 38, again showing the basket assembly 38 in an expanded form, while fig. 4 shows the basket assembly 38 in a collapsed form formed within the insertion tube 30 of the introducer sheath. In the expanded form (fig. 2 and 3), the ridges 214 form a spherical helical shape, and in the collapsed form (fig. 4), the ridges 214 are disposed generally along the longitudinal axis 86 of the insertion tube 30.

As shown in fig. 2, basket assembly 38 includes a single ridge 214 attached to the end of tubular shaft 84. During a medical procedure, the medical professional 34 may deploy the basket assembly 38 by extending the tubular shaft 84 from the insertion tube 30 (shown in fig. 4), causing the basket assembly 38 to exit the insertion tube and transition to the expanded form. The ridges 214 may have an oval (e.g., circular) or rectangular (which may appear flat) cross-section and comprise a flexible, resilient material (e.g., a shape memory alloy such as nickel titanium (also known as nitinol), cobalt chromium, or any other suitable material).

In embodiments described herein, electrode 40 may be configured to deliver ablation energy (RF and/or IRE) to tissue in heart 26. Additionally or alternatively, the electrodes may also be used to determine the position of basket assembly 38 and/or measure physiological characteristics, such as local surface potentials at corresponding locations on tissue in heart 26. As further described herein, electrode 40 may be biased such that a greater portion of electrode 40 faces outward from basket assembly 39 such that electrode 40 delivers a greater amount of electrical energy outward away from basket assembly 38 (i.e., toward heart 26 tissue) than inward toward basket assembly 38.

Examples of materials that are ideally suited for forming electrode 40 include gold, platinum, and palladium (and their corresponding alloys). These materials also have a high thermal conductivity that allows the minimal heat generated on the tissue (i.e., by the ablation energy delivered to the tissue) to be conducted through the electrode to the back of the electrode (i.e., the portion of the electrode on the inside of the ridge) and then to the blood pool in heart 26.

As shown in FIG. 2, the ridges 214 may form a generally spherical helical shape when in the expanded form. For example, the ridge 214 may have a first end disposed proximate to the distal end of the tubular shaft 84 and a second end positioned proximate to the distal end 36 of the medical probe 22 (i.e., the second end of the ridge 214 may be the distal end 36 of the medical probe 22 when the basket assembly 38 is in the expanded form). When in the expanded form, the ridges 214 may spiral outwardly along the ridges from the first end to a first position between the first end and the second end. The ridges 214 may spiral inwardly from the first position to the second end to complete a spherical spiral shape.

The electrodes 40 may be spaced apart along the spine 214 such that the electrodes 40 are configured to face outwardly and are positioned to contact or nearly contact heart tissue when the basket assembly 38 is in the expanded form. In this manner, basket assembly 38 may be configured to position electrode 40 to facilitate an IRE ablation procedure. For example, the electrodes 40 may be spaced apart along the ridges 214 such that electrodes disposed along a first turn of the helix may be offset relative to second electrodes 40 disposed along a second turn of the helix. In other words, the electrodes 40 may be offset from adjacent electrodes 40 to ensure that the basket assembly 38 is able to adequately deliver electrical pulses to the heart tissue.

Fig. 3 is a schematic illustration showing an exploded side view of a medical probe 22 in an expanded form in accordance with the disclosed technology. As shown in fig. 3, the ridges 214 may be helical in shape such that the perimeter of the basket assembly 38 forms a generally spherical shape when in the expanded form. The ridges 214 may be configured to form a generally spherical shape having a predetermined diameter D when in the expanded form. Diameter D may be sized to ensure that basket assembly 38 may be fitted within the chamber of the heart and that electrodes 40 are sufficiently spaced apart to perform an IRE ablation procedure. The ridges 214 may also be configured such that the perimeter of the basket assembly 38 forms a flattened spherical shape when in the expanded form such that the distance between the proximal and distal ends of the basket 38 are closer together when compared to a spherical basket. The oblate spheroid shape may have a diameter D that is the same as the diameter of the spheroid shape and is sized to ensure that basket assembly 38 fits within the chamber of the heart and that electrodes 40 are sufficiently spaced apart to perform an IRE ablation procedure.

The medical probe 22 may include a ridge retention hub 90 disposed proximate the distal end 85 of the tubular shaft 84. The ridge retention hub 90 may be inserted into the tubular shaft 84 and attached to the tubular shaft 84. The ridge retaining hub 90 may comprise a cylindrical member including a release groove 97 provided on an outer surface of the cylindrical member to allow the ridge 214 to fit into and be retained in the release groove 97. For example, the ridge retaining hub 90 may include a release groove 97 sized to receive the attachment end 216 of the ridge 214. The attachment end 216 may be a generally linear end of the spine 214. The attachment end 216 may be configured to extend outwardly from the spine retention hub 90 such that the basket assembly 38 is positioned outwardly from the spine retention hub 90 and, thus, the tubular shaft 84. In this manner, the ridges 214 may be configured to position the basket assembly 38 away from the distal end of the tubular shaft 84 and away from the distal end of the insertion tube 30 when the basket assembly is deployed. The spine retention hub 90 may also include at least one electrode 99 disposed at a distal portion of the spine retention hub 90. The electrode 99 disposed at the distal end of the retention hub 90 may be used in combination with the electrode 40 on the spine 214 or, alternatively, may be used independently of the electrode 40 for reference mapping or ablation.

As described above, the console 24 includes an irrigation module 60 that delivers irrigation fluid to the distal end 36. The ridge retention hub 90 may include one or more irrigation openings 98, wherein each given irrigation opening 98 may be angled to spray or otherwise disperse irrigation fluid to tissue in a given electrode 40 or heart 26. Since the electrode 40 does not include irrigation openings that deliver irrigation fluid, the configurations described herein enable heat transfer from the tissue to the portion of the electrode on the inside of the ridge 214 (i.e., during an ablation procedure), and the electrode 40 may be cooled by aligning the irrigation fluid to the portion of the electrode 40 on the inside of the ridge 214 via the irrigation openings 98.

Fig. 4 is a schematic illustration showing a side view of a medical probe 22 in a collapsed form in accordance with the disclosed technology. As shown in fig. 4, the basket assembly 38 may be pulled into the flexible insertion tube 30 such that the ridges 214 are disposed generally linearly along the longitudinal axis 86 of the medical probe 22 when in the collapsed form. In other words, when the tubular shaft 84 is pulled into the flexible insertion tube 30, the basket assembly 38 may be pulled into the flexible insertion tube 30. Because basket assembly 38 includes ridges 214 made of a flexible, resilient material, basket assembly 38 may be elongated such that ridges 214 (and, where necessary, basket assembly 38) are disposed generally linearly along longitudinal axis 86 of medical probe 22. However, as will be appreciated, because the ridges 214 comprise a flexible, resilient material, the ridges 214 may not form a perfectly straight configuration, but may include various bends or curves when pulled into the flexible insertion tube 30.

Fig. 5 is a schematic illustration of a method of forming ridges 214 from a planar sheet 502 of elastomeric material in accordance with the disclosed technology. The ridges 214 may be formed by cutting the first spiral 214A and the second spiral 214B into a planar sheet 502 of elastic material (e.g., a shape memory alloy such as nickel titanium (also known as nitinol), cobalt chromium, or any other suitable material). The first spiral 214A and the second spiral 214B may be attached to each other with a linear portion 214C. The first spiral 214A and the second spiral 214B may each have a diameter D of equal size. The linear portion 214C may have a length L that is the same size as the diameter D or a different size than the diameter D.

After cutting the first spiral 214A, the second spiral 214B, and the linear portion 214C from the planar sheet 502 of elastic material, the ridges 214 may be formed by forming the first spiral 214A, the second spiral 214B, and the linear portion 214C into a spherical spiral shape. For example, the first spiral 214A may expand in a first direction to form a three-dimensional spiral, the second spiral 214B may expand in a second direction to form a second three-dimensional spiral, and the linear portion 214C may coil or wrap between the first spiral 214A and the second spiral 214B to complete a spherical spiral. The ridges 214 may be curved to maintain a spherical helical shape. Alternatively or in addition, the ridges 214 may be heat treated to maintain the spherical helical shape. Likewise, the spine assembly 210A or 210B may be formed by laser cutting a cylindrical hollow stock material with a laser mounted for rotation about (and translation to) a longitudinal axis of the cylindrical stock material while cutting through the cylindrical stock material. As will be appreciated, the described methods are provided for illustrative purposes only and should not be construed as limiting.

Fig. 6 is a schematic illustration of a method of forming at least a portion of a ridge 214 from a cylindrical hollow tube 602 of elastomeric material in accordance with the disclosed technology. As shown in fig. 6, the ridges 214 may be formed from a cylindrical hollow tube 602 of elastomeric material (e.g., a shape memory alloy such as nickel titanium (also known as nitinol), cobalt chrome, or any other suitable material) by cutting the cylindrical hollow tube 602 of elastomeric material into helical portions. For example, the spiral portion of the cylindrical hollow tube 602 of elastic material may be formed by cutting the cylindrical hollow tube 602 of elastic material at an angle starting from one end of the cylindrical hollow tube 602 of elastic material. The ridges 214 may be cut, for example, by rotating a cylindrical hollow tube 602 of elastomeric material and moving a knife, laser, or other cutting device longitudinally along the length of the cylindrical hollow tube 602 of elastomeric material. Alternatively, the cylindrical hollow tube may remain stationary as the cutting device rotates around the cylindrical hollow tube.

After cutting the ridges 214 from the cylindrical hollow tube 602 of elastomeric material, the ridges 214 may be formed into a spherical spiral by bending the ridges 214 into a spherical spiral shape. The ridges 214 may retain the spherical helical shape simply by bending into the spherical helical shape. Alternatively or in addition, the ridges 214 may be heat treated to maintain the spherical helical shape. As will be appreciated, the method just described is provided for illustrative purposes only and should not be construed as limiting.

Alternatively or in addition, the ridges 214 may be formed by coiling round wire, flat wire, stamping flat wire, or other similar types of wire or material to form a spherical spiral. For example, the ridges 214 may be formed by bending round wires (or other selected wire types) until the desired spherical helical shape is achieved.

Referring back to fig. 2-4, one or more electrodes 40 may be attached to the spine 214 to form the basket assembly 38. In some examples, each electrode 40 may include a conductive material (e.g., gold, platinum, and palladium (and their respective alloys)). Turning to fig. 7A-7J, electrode 40 can have various cross-sectional shapes, curvatures, lengths, number of lumens, and lumen shapes as provided as examples in electrodes 740A-740E. Electrodes 740A-740E are provided to illustrate various configurations of electrodes 40 that may be used with medical device 22, but should not be construed as limiting. Those skilled in the art will appreciate that various other configurations of the electrode 40 may be used with the disclosed technology without departing from the scope of the present disclosure.

Each electrode 740A-740E may have an outer surface 774 that faces outwardly from electrode 740 and an inner surface 776 that faces inwardly toward electrode 740, with at least one lumen 770 formed through electrode 740. The lumen 770 may be sized and configured to receive the ridges 214 such that the ridges 214 may pass through the electrode 740. The lumen 770 may be a symmetrical opening through the electrodes 740A-740E and may be disposed offset relative to the longitudinal axis L-L of the respective electrode. In other examples, the lumen 770 may pass through the electrode 740 in a generally transverse direction relative to the longitudinal axis L-L of the respective electrode. Further, depending on the particular configuration, the lumen 770 may be positioned closer to the bottom surface, closer to the top surface, or closer to the middle of the electrode 740. In fig. 7A, 7C, and 7E-7J, the top surface is oriented toward the top of the drawing, the bottom surface is oriented toward the bottom of the drawing, and the middle is located between the top surface and the bottom surface. In other words, each electrode 740A-740E may include a lumen 770 that is offset relative to the centroid of the electrode 740A-740E.

In addition, as shown in fig. 7A-7F, the electrodes 740A-740C may have a wire relief 772 that forms a recess or depression in the electrode 740 adjacent the lumen 770 for passing one or more wires through the lumen 770 along with the corresponding ridges 214. The relief 772 may be sized to provide space for wires of the electrode 740 to pass through the electrode 740 so that the electrode 740 may be in electrical communication with the console 24.

Alternatively or in addition, the wire may be passed through the wire lumen 773, as shown by the example electrodes 740D and 740E in fig. 7G-7J. Although not depicted, the electrode 40 may include both a wire relief 772 adjacent the lumen 770 and a wire lumen 773. Such electrodes may allow additional wires to pass through the electrode body.

As shown in fig. 7A-7J, the electrodes 740A-740E may include various shapes, depending on the application. For example, as shown in fig. 7A and 7B, electrode 740A may comprise a substantially rectangular cuboid shape with rounded edges. In other examples, electrode 740B may include a substantially oval shape (as shown in fig. 7C and 7D); the electrodes 740C, 740D may have a contoured shape with a convex side and a concave side (as shown in fig. 7E-7H); or electrode 740E may have a contoured shape with substantially more material on the upper side near electrode 740E than on the lower side (as shown in fig. 7I and 7J). As will be appreciated by those skilled in the art, the various exemplary electrodes 740A-740E shown in fig. 7A-7J and described herein are provided for illustrative purposes and should not be construed as limiting.

Fig. 8A and 8B are schematic illustrations showing various insulating sheaths 880A, 880B of a given medical device 22 according to embodiments of the present invention. Fig. 8A is a front view of insulating jackets 880A, 880B, while fig. 8B is a perspective view thereof. The insulating sheaths 880A, 880B may be made of biocompatible, electrically insulating materials, such as polyamide-polyether (Pebax) copolymer, polyethylene terephthalate (PET), polyurethane, polyimide, parylene, silicone, and the like. In some examples, the insulating material may include a biocompatible polymer, including, but not limited to: polyether ether ketone (PEEK), polyglycolic acid (PGA), poly (lactic-co-glycolic acid) (PLGA), polycaprolactone (PCL), poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly-L-lactide, polydioxanone, polycarbonate and polyanhydride, wherein the ratio of certain polymers is selected to control the extent of the inflammatory reaction. The insulating jackets 880A, 880B may also include one or more additives or fillers, such as Polytetrafluoroethylene (PTFE), boron nitride, silicon carbide, aluminum oxide, aluminum nitride, zinc oxide, and the like. The insulating jackets 880A, 880B may help insulate the ridges 214 and/or the wires passing through the insulating jackets 880A, 880B from the electrode 40 to prevent arcing of the ridges 214 by the electrode 40 and/or mechanical wear of the wires passing through the insulating jackets 880A, 880B.

As shown in fig. 8A and 8B, the insulating jackets 880A, 880B may include a substantially trapezoidal cross-sectional shape. The insulating sheath may be comprised of a single lumen or multiple lumen configuration. The multi-lumen sheath may be configured such that the alloy frame and wire share a single lumen, while the second lumen may be used for irrigation. The alloy frame and wire may also occupy separate lumens, as described. For these designs, the insulating sheath may be continuous (individual sleeves extending from near the distal end of each alloy frame strut), segmented (bridging between electrode gaps), or a combination of both. Further, the insulating sheaths 880A, 880B may include a first lumen 882A, 882B and a second lumen 884A, 884B. The first lumens 882A, 882B may be configured to receive the ridges 214 while the second lumens 884A, 884B may be configured to receive wires, or vice versa. In other examples, the first lumens 882A, 882B and the second lumens 884A, 884B may each be configured to receive one or more wires that may be connected to one or more electrodes 40. Further, as shown in fig. 8B, the insulating sheaths 880A, 880B may include holes 886A, 886B through which wires may be electrically connected to the electrodes 40. Although shown in fig. 8B as being near the bottom of the insulating jackets 880A, 880B, the holes 886A, 886B may be positioned near the top or sides of the insulating jackets 880A, 880B. Further, the insulating jackets 880A, 880B may include a plurality of holes 886A, 886B, wherein each hole is disposed on the same side of the insulating jacket (i.e., top, bottom, left, right) or on a different side of the insulating jacket, depending on the application.

Fig. 9A and 9B are schematic illustrations showing cross-sectional views of a given line 900, 950 connectable to a given electrode 40 according to embodiments of the invention. Fig. 9A shows a solid core wire 900. Fig. 9B shows a stranded wire 950. Each wire 900, 950 may extend through at least a portion of the tubular shaft 84. The solid core wire 900 may include a conductive core material 902 and a conductive cover material 904 surrounding the conductive core material 902. Similarly, the strand 950 may include strands, each strand including a conductive core material 952 and a conductive cover material 954 surrounding the conductive core material 952. Each wire 900, 950 may include an insulating sheath 906 surrounding the conductor. Wires 900, 950 may be configured to withstand a voltage differential of adjacent wires sufficient to deliver an IRE pulse. Preferably, the wires 900, 950 can withstand at least 900V to 2000V, and more preferably at least 1800V to 4000V between adjacent wires. To reduce the likelihood of dielectric breakdown between conductors of adjacent lines, the conductive cover materials 904, 954 may have a lower conductivity than the core materials 902, 952.

The insulating sheath 906 may be configured to have a temperature rating of between 150 degrees celsius and 200 degrees celsius such that the electrically insulating sheath 906 melts or degrades (e.g., char and chip) during welding of the wire 900 to the electrode 40 (e.g., at a temperature of 300 degrees celsius), and thus the insulating sheath 906 of the wire 900 does not need to be mechanically stripped. In other examples, the insulating sheath 906 may have a temperature rating of greater than 200 degrees celsius to prevent the electrically insulating material 902 from melting or degrading (e.g., charring and chipping) during manufacture and/or during use of the medical probe 22. The insulating sheath 906 may be mechanically stripped from the wire 900 prior to electrically connecting the wire 900 to the electrode 40.

Fig. 10 is a flow chart of a method 1000 of assembling basket assembly 38 in accordance with an embodiment of the present invention. The method 100 may include cutting 1002 a planar sheet of elastic material to form two connected spirals (e.g., as explained with respect to fig. 5). The planar sheet of elastomeric material may comprise a shape memory alloy, such as nickel titanium (also known as nitinol), cobalt chrome, or any other suitable material. The method 1000 may include forming 1004 a ridge having a spherical helical shape from two connected spirals. The two spirals can be connected by a linear section. The method 1006 may further include inserting 1006 the ridges into the lumen of the one or more electrodes and fitting 1008 the ends of the ridges into a tubular shaft sized to traverse the vasculature. As will be appreciated by those skilled in the art having the benefit of this disclosure, fitting 1008 the ends of the ridges into the tubular shaft may include attaching the ridges 214 to the ridge-retaining hub 90. In addition, the ridge retention hub 90 and/or the ridge 214 and the tubular shaft 84 may be inserted into the flexible insertion tube 30 to form the medical probe 22.

Fig. 11 is a flow chart of another method 1100 of assembling basket assembly 38 in accordance with an embodiment of the present invention. The method 1100 may include cutting 1102 a cylindrical hollow tube of elastic material to form a spiral (e.g., as explained with respect to fig. 6). The method 1100 may include forming 1104 a ridge from a helix to have a spherical helical shape, inserting 1106 the ridge into a lumen of one or more electrodes, and fitting 1108 an end of the ridge into a tubular shaft sized to traverse the vasculature. As with method 1000, fitting 1108 the ends of the ridges into the tubular shaft may include attaching the ridges 214 to the ridge-retaining hub 90. In addition, the ridge retention hub 90 and/or the ridge 214 and the tubular shaft 84 may be inserted into the flexible insertion tube 30 to form the medical probe 22.

Fig. 12 is a flow chart of another method 1200 of assembling basket assembly 38 in accordance with an embodiment of the present invention. Method 1200 may include coiling 1202 an elongated sheet of elastic material to form a ridge having a spherical helical shape. The method 1200 may include inserting 1204 a ridge into a lumen of one or more electrodes, and fitting 1206 an end of the ridge into a tubular shaft sized to traverse vasculature. As previously described, fitting 1208 the ends of the ridges into the tubular shaft may include attaching the ridges 214 to the ridge-retaining hub 90. In addition, the ridge retention hub 90 and/or the ridge 214 and the tubular shaft 84 may be inserted into a flexible insertion tube to form the medical probe 22.

Examples are described below that may be used alone or in various arrangements with one another, and such examples (in various arrangements) may be used to define the scope of the invention.

Embodiment 1) the single ridge may comprise a first end and a second end. The first end may be positioned proximate to the distal end of the tubular shaft and the second end may be positioned proximate to the distal end of the medical probe in the collapsed form.

Embodiment 2) in the expanded form, the single ridges may be configured to: (1) Spiral outwardly from the first end to a first position located along the single ridge between the first end and the second end, and (2) spiral inwardly from the first position to the second end.

Embodiment 3) the single ridge may be a single unitary structure formed from a planar sheet of elastomeric material. A single ridge may be formed from a planar sheet of elastomeric material by cutting two spirals into a planar sheet of elastomeric material. The two spirals may be connected to each other. For example, two spirals may be connected to each other by a linear portion. The linear portion may be connected to both spirals proximate a respective end of each spiral that is furthest from the center point of each respective spiral. In the expanded form, the two helical and linear portions may be coiled to form a generally spherical outer periphery of a single ridge.

Example 4) a single ridge may comprise a continuous elongated sheet of elastic material coiled to form a generally spherical outer periphery. The single ridge may comprise nitinol, cobalt chrome, or any other suitable material. The single ridge may form a generally oblate spheroid shape.

Embodiment 5) the medical probe may further comprise a ridge retention hub disposed proximate the distal end of the tubular shaft. The ridge retaining hub may comprise a cylindrical member including a release groove provided on an outer surface of the cylindrical member to allow a single ridge to fit into and be retained in the release groove. The retention hub may also include at least one electrode disposed at a distal portion of the retention hub.

Example 6) each electrode may include a relief adjacent the lumen to allow the wire to extend adjacent the lumen. The wire may be electrically insulated from the individual ridges. The wire may be electrically connected to one or more electrodes. At least a portion of the wire may include a conductive core material having a first conductivity, a conductive cover material having a second conductivity less than the first conductivity, and an insulating sheath. The conductive cover material may surround the conductive core material, and the insulating sheath may surround the conductive cover material.

Embodiment 7) at least a portion of the wire may include a plurality of strands and an insulating sheath surrounding the plurality of strands. Each strand of the plurality of strands may include a conductive core material having a first conductivity and a conductive cover material having a second conductivity less than the first conductivity. The conductive cover material may surround the conductive core material.

Embodiment 8) the medical probe may further comprise a separate lumen configured to receive a wire having insulation, wherein the wire is capable of delivering at least 900 volts (V) in the absence of dielectric breakdown of the insulation. The one or more electrodes may be configured to deliver electrical pulses for irreversible electroporation. The pulse may have a voltage of at least 900 volts (V).

Embodiment 9) the medical probe may further comprise an irrigation opening disposed proximate the distal end of the tubular shaft. The irrigation openings may be configured to deliver irrigation fluid to an area proximate to the one or more electrodes.

Embodiment 10) the medical probe may further comprise an insulating sleeve disposed over the single ridge and within the lumen of the respective electrode. The insulating sleeve may include a first lumen through which the post extends and a second lumen through which the wire extends, the first lumen and the second lumen being different from one another. The cross-sectional shape of each electrically insulating sleeve may be a substantially trapezoidal shape.

Embodiment 11) the electrode may comprise an elliptical body-type electrode having a lumen extending through the elliptical body. The electrode may comprise a protruding electrode.

Example 12) according to another embodiment of the present invention, a method of constructing a medical probe is provided. The method may include cutting two joined spirals into a planar sheet of elastic material to form a single ridge. The method may further include forming the single ridge to have a predetermined shape that is a generally spherical helical shape such that the single ridge is configured to transition from the elongated shape in the collapsed form to the predetermined shape in the expanded form. The method may include inserting a single ridge through at least one lumen of the electrode and fitting an end of the single ridge to a tubular shaft sized to traverse the vasculature such that a first end of the single ridge is positioned proximate a distal end of the tubular shaft and a second end of the single ridge is positioned proximate a distal end of the medical probe.

Example 13) when in the expanded form, the single ridge may be configured to: (1) Spiral outwardly from the first end to a first position located along the single ridge between the first end and the second end, and (2) spiral inwardly from the first position to the second end.

Example 14) cutting two joined spirals into a planar sheet of elastic material may comprise forming a linear portion joining the two spirals. The linear portion may be connected to both spirals proximate a respective end of each spiral that is furthest from the center point of each respective spiral.

Example 15) the single ridge may comprise nitinol, cobalt chrome, or any other suitable material. The single ridge may form a generally oblate spheroid shape of the predetermined shape.

Embodiment 16) each electrode may include a relief adjacent the lumen to allow the wire to extend adjacent the lumen. The wire may be electrically insulated from the individual ridges. The method may further comprise electrically connecting the wire to one or more electrodes. At least a portion of the wire may include a conductive core material having a first conductivity, a conductive cover material having a second conductivity less than the first conductivity, and an insulating sheath. The conductive cover material may surround the conductive core material, and the insulating sheath may surround the conductive cover material. At least a portion of the wire may include a plurality of strands and an insulating sheath surrounding the plurality of strands. Each strand of the plurality of strands may include a conductive core material having a first conductivity and a conductive cover material having a second conductivity less than the first conductivity. The conductive cover material may surround the conductive core material.

Example 17) the medical probe may further comprise a separate lumen configured to receive a wire having insulation, wherein the wire is capable of delivering at least 900V in the absence of dielectric breakdown of insulation. The one or more electrodes may be configured to deliver electrical pulses for irreversible electroporation. The pulse may be a voltage of at least 900 volts (V).

Embodiment 18) the medical probe may further comprise an irrigation opening disposed proximate the distal end of the tubular shaft. The irrigation openings may be configured to deliver irrigation fluid to an area proximate to the one or more electrodes.

Embodiment 19) the method may further comprise disposing an insulating sleeve over the single ridge and within the lumen of the respective electrode. The insulating sleeve may include a first lumen through which the post extends and a second lumen through which the wire extends. The first lumen and the second lumen may be different from each other. The cross-sectional shape of each electrically insulating sleeve may be a substantially trapezoidal shape.

Embodiment 20) the electrode may be an elliptical body-type electrode having a lumen extending through the elliptical body. The electrode may also be a protruding electrode.

As will be appreciated by those of skill in the art, the methods 1000, 1100, and 1200 just described may include any of the various features of the disclosed technology described herein and may vary depending on the particular configuration. Thus, the methods 1000, 1100, and 1200 should not be construed as limited to the particular steps and sequence of steps explicitly described herein.

The above embodiments are cited by way of example, and the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described hereinabove as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not disclosed in the prior art.

Claims

1. A medical probe, comprising:

a tubular shaft having a proximal end and a distal end, the tubular shaft extending along a longitudinal axis;

an expandable basket assembly proximate the distal end of the tubular shaft, the expandable basket assembly comprising:

a single ridge comprising an elastic material extending generally linearly along the longitudinal axis in a collapsed form and forming a helical member defining a generally spherical outer periphery in an expanded form; and

one or more electrodes coupled to the single spine, each electrode including a lumen offset relative to a centroid of the electrode such that the single spine extends through the lumen of each of the one or more electrodes.

2. The medical probe of claim 1, the single ridge comprising a first end and a second end, the first end being positioned proximate to the distal end of the tubular shaft and the second end being positioned proximate to the distal end of the medical probe in the collapsed form.

3. The medical probe of claim 2, wherein in the expanded form, the single ridge is configured to: (1) Outwardly from the first end to a first position located along the single ridge between the first end and the second end, and (2) inwardly from the first position to the second end.

4. The medical probe of claim 1, the single ridge comprising a single unitary structure formed from a planar sheet of the resilient material.

5. The medical probe of claim 1, the single ridge comprising a continuous elongated sheet of the resilient material coiled to form the generally spherical outer perimeter.

6. The medical probe of claim 1, wherein the single ridge comprises nitinol.

7. The medical probe of claim 1, wherein the single ridge forms a generally oblate spheroid shape.

8. The medical probe of claim 1, further comprising a ridge-retaining hub disposed proximate the distal end of the tubular shaft, the ridge-retaining hub comprising a cylindrical member including a release groove disposed on an outer surface of the cylindrical member to allow the single ridge to fit into and be retained in the release groove, the ridge-retaining hub further comprising at least one electrode disposed at a distal portion of the ridge-retaining hub.

9. The medical probe of claim 1, wherein each electrode includes a relief adjacent the lumen to allow a wire to extend adjacent the lumen.

10. The medical probe of claim 9, wherein the wire is electrically insulated from the single ridge and electrically connected to an electrode of the one or more electrodes.

11. The medical probe of claim 10, wherein at least a portion of the wire comprises: a conductive core material having a first conductivity; a conductive cover material having a second conductivity less than the first conductivity, the conductive cover material surrounding the conductive core material; and an insulating sheath surrounding the conductive cover material.

12. The medical probe according to claim 10,

wherein at least a portion of the wire comprises a plurality of strands and an insulating sheath surrounding the plurality of strands, an

Wherein each strand of the plurality of strands comprises a conductive core material having a first conductivity and a conductive cover material having a second conductivity less than the first conductivity, respectively, the conductive cover material surrounding the conductive core material.

13. The medical probe of claim 1, wherein the one or more electrodes are configured to deliver an electrical pulse for irreversible electroporation, the pulse having a voltage of at least 900 volts (V).

14. The medical probe of claim 1, further comprising an irrigation opening disposed proximate the distal end of the tubular shaft, the irrigation opening configured to deliver irrigation fluid to an area proximate the one or more electrodes.

15. The medical probe of claim 1, further comprising an insulating sleeve disposed over the single ridge and within the lumen of the respective electrode.

16. The medical probe of claim 15, wherein the insulating sleeve includes a first lumen through which the struts extend and a second lumen through which the wires extend, the first lumen and the second lumen being different from one another.

17. The medical probe of claim 16, wherein the cross-sectional shape of each electrically insulating sleeve comprises a substantially trapezoidal shape.

18. A method of constructing a medical probe, the method comprising:

cutting two joined spirals into a planar sheet of elastomeric material to form a single ridge;

forming the single ridge into a predetermined shape having a generally spherical helical shape such that the single ridge is configured to transition from an elongated shape in a collapsed form to the predetermined shape in an expanded form;

inserting the single ridge into at least one lumen through an electrode; and

the ends of the single ridges are assembled to a tubular shaft that is sized to traverse the vasculature such that a first end of the single ridges are positioned proximate to a distal end of the tubular shaft and a second end of the single ridges are positioned proximate to a distal end of the medical probe.

19. The method of claim 18, wherein the single ridge is configured to, when in the expanded form: (1) Outwardly from the first end to a first position located along the single ridge between the first end and the second end, and (2) inwardly from the first position to the second end.

20. The method of claim 18, wherein cutting two connected spirals into a planar sheet of elastic material further comprises forming a linear portion connecting the two spirals, the linear portion being connected to the two spirals proximate a respective end of each spiral, the respective end being furthest from a center point of each respective spiral.