Patent Description:
Cardiac arrhythmias, such as atrial fibrillation (AF), occur when regions of cardiac tissue abnormally conduct electric signals to adjacent tissue. This disrupts the normal cardiac cycle and causes asynchronous rhythm. Certain procedures exist for treating arrhythmia, including surgically disrupting the origin of the signals causing the arrhythmia and disrupting the conducting pathway for such signals. By selectively ablating cardiac tissue by application of energy via a catheter, it is sometimes possible to cease or modify the propagation of unwanted electrical signals from one portion of the heart to another.

Many current ablation approaches in the art tend to utilize radiofrequency (RF) electrical energy to heat tissue. RF ablation can have certain rare drawbacks due to operator's skill, such as heightened risk of thermal cell injury which can lead to tissue charring, burning, steam pop, phrenic nerve palsy, pulmonary vein stenosis, and esophageal fistula. Cryoablation is an alternative approach to RF ablation that generally reduces thermal risks associated with RF ablation but may present tissue damage due to the very low temperature nature of such devices. Maneuvering cryoablation devices and selectively applying cryoablation, however, is generally more challenging compared to RF ablation; therefore cryoablation is not viable in certain anatomical geometries which may be reached by electrical ablation devices.

Some ablation approaches use irreversible electroporation (IRE) to ablate cardiac tissue using nonthermal ablation methods. IRE delivers short pulses of high voltage to tissues and generates an unrecoverable permeabilization of cell membranes. Delivery of IRE energy to tissues using multi-electrode catheters was previously proposed in the patent literature. Examples of systems and devices configured for IRE ablation are disclosed in <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

<CIT> describes an apparatus for medical catheterization, comprising: an assembly adapted for introduction into a heart; and a catheter slidable through the assembly into a chamber of the heart, comprising: a sheath; and a multi-electrode probe movable through the sheath in a compact configuration, the probe having a distal end and a shape memory that urges the probe to assume an expanded spiral configuration when advanced beyond the sheath into the chamber.

Regions of cardiac tissue can be mapped by a catheter to identify the abnormal electrical signals. The same or different catheter can be used to perform ablation. Some example catheters include a number of spines with electrodes positioned thereon. The electrodes are generally attached to the spines and secured in place by soldering, welding, or using an adhesive. Furthermore, multiple linear spines are generally assembled together by attaching both ends of the linear spines to a tubular shaft (e.g., a pusher tube) to form a spherical basket. Due to the small size of the spines and the electrodes, however, adhering the electrodes to the spines and then forming a spherical basket from the multiple linear spines can be a difficult task, increasing the manufacturing time and cost and the chances that the electrode fails due to an improper bond or misalignment. What is needed, therefore, are devices and methods of forming an improved basket assembly that can position the electrodes in the proper location when in an expanded state while also reducing the overall manufacturing complexity of the basket assembly.

Various embodiments of a medical probe, including certain methods related thereto are provided. The inventive probe is defined in independent claim <NUM>, and the inventive method of constructing a medical probe is defined in claim <NUM>.

As used herein, the term "proximal" indicates a location closer to the operator or physician whereas "distal" indicates a location further away to the operator or physician.

As discussed herein, vasculature of a "patient," "host," "user," and "subject" can be vasculature of a human or any animal. It should be appreciated that an animal can be a variety of any applicable type, including, but not limited thereto, mammal, veterinarian animal, livestock animal or pet type animal, etc. As an example, the animal can be a laboratory animal specifically selected to have certain characteristics similar to a human (e.g., rat, dog, pig, monkey, or the like). It should be appreciated that the subject can be any applicable human patient, for example.

As discussed herein, "operator" can include a doctor, surgeon, technician, scientist, or any other individual or delivery instrumentation associated with delivery of a multi-electrode catheter for the treatment of drug refractory atrial fibrillation to a subject.

As discussed herein, the term "ablate" or "ablation", as it relates to the devices and corresponding systems of this disclosure, refers to components and structural features configured to reduce or prevent the generation of erratic cardiac signals in the cells by utilizing non-thermal energy, such as irreversible electroporation (IRE), referred throughout this disclosure interchangeably as pulsed electric field (PEF) and pulsed field ablation (PFA). Ablating or ablation as it relates to the devices and corresponding systems of this disclosure is used throughout this disclosure in reference to non-thermal ablation of cardiac tissue for certain conditions including, but not limited to, arrhythmias, atrial flutter ablation, pulmonary vein isolation, supraventricular tachycardia ablation, and ventricular tachycardia ablation. The term "ablate" or "ablation" also includes known methods, devices, and systems to achieve various forms of bodily tissue ablation as understood by a person skilled in the relevant art.

As discussed herein, the terms "bipolar" and "unipolar" when used to refer to ablation schemes describe ablation schemes which differ with respect to electrical current path and electric field distribution. "Bipolar" refers to ablation scheme utilizing a current path between two electrodes that are both positioned at a treatment site; current density and electric flux density is typically approximately equal at each of the two electrodes. "Unipolar" refers to ablation scheme utilizing a current path between two electrodes where one electrode having a high current density and high electric flux density is positioned at a treatment site, and a second electrode having comparatively lower current density and lower electric flux density is positioned remotely from the treatment site.

As discussed herein, the terms "biphasic pulse" and "monophasic pulse" refer to respective electrical signals. "Biphasic pulse" refers to an electrical signal having a positive-voltage phase pulse (referred to herein as "positive phase") and a negative-voltage phase pulse (referred to herein as "negative phase"). "Monophasic pulse" refers to an electrical signal having only a positive or only a negative phase. Preferably, a system providing the biphasic pulse is configured to prevent application of a direct current voltage (DC) to a patient. For instance, the average voltage of the biphasic pulse can be zero volts with respect to ground or other common reference voltage. Additionally, or alternatively, the system can include a capacitor or other protective component. Where voltage amplitude of the biphasic and/or monophasic pulse is described herein, it is understood that the expressed voltage amplitude is an absolute value of the approximate peak amplitude of each of the positive-voltage phase and/or the negative-voltage phase. Each phase of the biphasic and monophasic pulse preferably has a square shape having an essentially constant voltage amplitude during a majority of the phase duration. Phases of the biphasic pulse are separated in time by an interphase delay. The interphase delay duration is preferably less than or approximately equal to the duration of a phase of the biphasic pulse. The interphase delay duration is more preferably about <NUM>% of the duration of the phase of the biphasic pulse.

As discussed herein, the terms "tubular" and "tube" are to be construed broadly and are not limited to a structure that is a right cylinder or strictly circumferential in cross-section or of a uniform cross-section throughout its length. For example, the tubular structures are generally illustrated as a substantially right cylindrical structure. However, the tubular structures may have a tapered or curved outer surface without departing from the scope of the present disclosure.

The term "temperature rating", as used herein, 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 crumbling) of the component.

The present disclosure is related to systems, methods or uses and devices which utilize end effectors having electrodes affixed to spines. Example systems, methods, and devices of the present disclosure may be particularly suited for IRE ablation of cardiac tissue to treat cardiac arrhythmias. Ablative energies are typically provided to cardiac tissue by a tip portion of a catheter which can deliver ablative energy alongside the tissue to be ablated. Some example catheters include three-dimensional structures at the tip portion and are configured to administer ablative energy from various electrodes positioned on the three-dimensional structures. Ablative procedures incorporating such example catheters can be visualized using fluoroscopy.

Ablation of cardiac tissue using application of a thermal technique, such as radio frequency (RF) energy and cryoablation, to correct a malfunctioning heart is a well-known procedure. Typically, to successfully ablate using a thermal technique, cardiac electropotentials need to be measured at various locations of the myocardium. In addition, temperature measurements during ablation provide data enabling the efficacy of the ablation. Typically, for an ablation procedure using a thermal technique, the electropotentials and the temperatures are measured before, during, and after the actual ablation.

RF approaches can have risks that can lead to tissue charring, burning, steam pop, phrenic nerve palsy, pulmonary vein stenosis, and esophageal fistula. Cryoablation is an alternative approach to RF ablation that can reduce some thermal risks associated with RF ablation. However maneuvering cryoablation devices and selectively applying cryoablation is generally more challenging compared to RF ablation; therefore cryoablation is not viable in certain anatomical geometries which may be reached by electrical ablation devices.

IRE as discussed in this disclosure is a non-thermal cell death technology that can be used for ablation of atrial arrhythmias. To ablate using IRE/PEF, biphasic voltage pulses are applied to disrupt cellular structures of myocardium. The biphasic pulses are non-sinusoidal and can be tuned to target cells based on electrophysiology of the cells. In contrast, to ablate using RF, a sinusoidal voltage waveform is applied to produce heat at the treatment area, indiscriminately heating all cells in the treatment area. IRE therefore has the capability to spare adjacent heat sensitive structures or tissues which would be of benefit in the reduction of possible complications known with ablation or isolation modalities. Additionally, or alternatively, monophasic pulses can be utilized.

Electroporation can be induced by applying a pulsed electric field across biological cells to cause reversable (temporary) or irreversible (permanent) creation of pores in the cell membrane. The cells have a transmembrane electrostatic potential that is increased above a resting potential upon application of the pulsed electric field. While the transmembrane electrostatic potential remains below a threshold potential, the electroporation is reversable, meaning the pores can close when the applied pulse electric field is removed, and the cells can self-repair and survive. If the transmembrane electrostatic potential increases beyond the threshold potential, the electroporation is irreversible, and the cells become permanently permeable. As a result, the cells die due to a loss of homeostasis and typically die by programmed cell death or apoptosis, which is believed to leave less scar tissue as compared to other ablation modalities. Generally, cells of differing types have differing threshold potential. For instance, heart cells have a threshold potential of approximately <NUM> V/cm, whereas for bone it is <NUM> V/cm. These differences in threshold potential allow IRE to selectively target tissue based on threshold potential.

The solution of this disclosure includes systems and methods for applying electrical signals from catheter electrodes positioned in the vicinity of myocardial tissue, preferably by applying a pulsed electric field effective to induce electroporation in the myocardial tissue. The systems and methods can be effective to ablate targeted tissue by inducing irreversible electroporation. In some examples, the systems and methods can be 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 allowing cells to repair. Reversible electroporation does not kill the cells but allows a physician to see the effect of reversible electroporation on electrical activation signals in the vicinity of the target location. Example systems and methods for reversible electroporation is disclosed in <CIT>.

The pulsed electric field, and its effectiveness to induce reversible and/or irreversible electroporation, can be affected by physical parameters of the system and biphasic pulse parameters of the electrical signal. Physical parameters can include electrode contact area, electrode spacing, electrode geometry, etc. examples presented herein generally include physical parameters adapted to effectively induce reversible and/or irreversible electroporation. Biphasic pulse parameters of the electrical signal can include voltage amplitude, pulse duration, pulse interphase delay, inter-pulse delay, total application time, delivered energy, etc. In some examples, parameters of the electrical signal can be adjusted to induce both reversible and irreversible electroporation given the same physical parameters. Examples of various systems and methods of ablation including IRE are presented in <CIT>,<CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

To deliver pulsed field ablation (PFA) in an IRE (irreversible electroporation) procedure, electrodes should contact the tissue being ablated with a sufficiently large surface area. As described hereinbelow, the medical probe includes a tubular shaft having proximal and distal ends, and a basket assembly at the distal end of the tubular shaft. The basket assembly includes a spine and a plurality of electrode assemblies. The spine can form a spiral member defining a generally spherical outer periphery when in an expanded form.

<FIG> is a schematic, pictorial illustration of a medical system <NUM> including a medical probe <NUM> and a control console <NUM>, in accordance with an embodiment of the present invention. Medical system <NUM> may be based, for example, on the CARTOR system, produced by Biosense Webster Inc. of <NUM> Technology Drive, Suite <NUM>, Irvine, CA <NUM> USA. In embodiments described hereinbelow, medical probe <NUM> can be used for diagnostic or therapeutic treatment, such as for performing ablation procedures in a heart <NUM> of a patient <NUM>. Alternatively, medical probe <NUM> may be used, mutatis mutandis, for other therapeutic and/or diagnostic purposes in the heart or in other body organs.

Medical probe <NUM> includes a flexible insertion tube <NUM> and a handle <NUM> coupled to a proximal end of the insertion tube. During a medical procedure, a medical professional <NUM> can insert probe <NUM> through the vascular system of patient <NUM> so that a distal end <NUM> of the medical probe enters a body cavity such as a chamber of heart <NUM>. Upon distal end <NUM> entering the chamber of heart <NUM>, medical professional <NUM> can deploy a basket assembly <NUM> approximate a distal end <NUM> of the medical probe <NUM>. Basket assembly <NUM> can include a plurality of electrodes <NUM> affixed to a plurality of spines, as described in the description referencing FIGs. 2A and 2B hereinbelow. To start performing a medical procedure such as irreversible electroporation (IRE) ablation, medical professional <NUM> can manipulate handle <NUM> to position distal end <NUM> so that electrodes <NUM> engage cardiac tissue at a desired location or locations. Upon positioning the distal end <NUM> so that electrodes <NUM> engages cardiac tissue, the medical professional <NUM> can activate the medical probe <NUM> such that electrical pulses are delivered by the electrodes <NUM> to perform the IRE ablation.

The medical probe <NUM> can include a guide sheath and a therapeutic catheter, wherein the guide sheath includes the flexible insertion tube <NUM> and the handle <NUM> and the therapeutic catheter includes the basket assembly <NUM>, electrodes <NUM>, and a tubular shaft <NUM> (see <FIG>). The therapeutic catheter is translated through the guide sheath so that the basket assembly <NUM> is positioned in the heart <NUM>. The distal end <NUM> of the medical probe <NUM> corresponds to a distal end of the guide sheath when the basket assembly <NUM> is contained within the flexible insertion tube <NUM>, and the distal end <NUM> of the medical probe <NUM> corresponds to a distal end of the basket assembly <NUM> when the basket assembly <NUM> is extended from the distal end of the guide sheath. The medical probe <NUM> can be alternatively configured to include a second handle on the therapeutic catheter and other features as understood by a person skilled in the pertinent art.

In the configuration shown in <FIG>, control console <NUM> is connected, by a cable <NUM>, to body surface electrodes, which typically include adhesive skin patches <NUM> that are affixed to patient <NUM>. Control console <NUM> includes a processor <NUM> that, in conjunction with a tracking module <NUM>, determines location coordinates of distal end <NUM> inside heart <NUM>. Location coordinates can be determined based on electromagnetic position sensor output signals provided from the distal portion of the catheter when in the presence of a generated magnetic field. Location coordinates can additionally, or alternatively be based on impedances and/or currents measured between adhesive skin patches <NUM> and electrodes <NUM> that are affixed to basket assembly <NUM>. In addition to being used as location sensors during a medical procedure, electrodes <NUM> may perform other tasks such as ablating tissue in the heart.

As described hereinabove, in conjunction with tracking module <NUM>, processor <NUM> may determine location coordinates of distal end <NUM> inside heart <NUM> based on impedances and/or currents measured between adhesive skin patches <NUM> and electrodes <NUM>. Such a determination is typically after a calibration process relating the impedances or currents to known locations of the distal end has been performed. While embodiments presented herein describe electrodes <NUM> that are preferably configured to deliver IRE ablation energy to tissue in heart <NUM>, configuring electrodes <NUM> to deliver any other type of ablation energy to tissue in any body cavity is possible. Furthermore, although described in the context of being electrodes <NUM> that are configured to deliver IRE ablation energy to tissue in the heart <NUM>, one skilled in the art will appreciate that the disclosed technology can be applicable to electrodes used for mapping and/or determining various characteristics of an organ or other part of the patient's <NUM> body.

Processor <NUM> may include real-time noise reduction circuitry <NUM> typically configured as a field programmable gate array (FPGA), followed by an analog-to-digital (A/D) signal conversion integrated circuit <NUM>. The processor can be programmed to perform one or more algorithms and uses circuitry <NUM> and circuit <NUM> as well as features of modules to enable the medical professional <NUM> to perform the IRE ablation procedure.

Control console <NUM> also includes an input/output (I/O) communications interface <NUM> that enables control console <NUM> to transfer signals from, and/or transfer signals to electrodes <NUM> and adhesive skin patches <NUM>. In the configuration shown in <FIG>, control console <NUM> additionally includes an IRE ablation module <NUM> and a switching module <NUM>.

IRE ablation module <NUM> is configured to generate IRE pulses having peak power in the range of tens of kilowatts. In some examples, the electrodes <NUM> are configured to deliver electrical pulses having a peak voltage of at least <NUM> volts (V). The medical system <NUM> performs IRE ablation by delivering IRE pulses to electrodes <NUM>. Preferably, the medical system <NUM> delivers biphasic pulses between electrodes <NUM> on the spine. Additionally, or alternatively, the medical system <NUM> delivers monophasic pulses between at least one of the electrodes <NUM> and a skin patch.

The system <NUM> may supply irrigation fluid (e.g., a saline solution) to distal end <NUM> and to the electrodes <NUM> via a channel (not shown) in the tubular shaft <NUM> (see <FIG>). Irrigation is sometimes utilized to reduce clot formation, stagnant blood flow or even reduce heat generated by ablation via the electrodes. Additionally, or alternatively, irrigation fluid can be supplied through the flexible insertion tube <NUM>. Control console <NUM> includes an irrigation module <NUM> to monitor and control irrigation parameters, such as the pressure and the temperature of the irrigation fluid. It is noted that while the preference for the exemplary embodiments of the medical probe is for IRE or PFA, it is possible to also use the medical probe separately only for RF ablation (unipolar mode with an external grounding electrode or bipolar mode) or in combination with IRE and RF ablations sequentially (certain electrodes in IRE mode and other electrodes in RF mode) or simultaneously (groups of electrodes in IRE mode and other electrodes in RF mode).

Based on signals received from electrodes <NUM> and/or adhesive skin patches <NUM>, processor <NUM> can generate an electroanatomical map <NUM> that shows the location of distal end <NUM> in the patient's body. During the procedure, processor <NUM> can present map <NUM> to medical professional <NUM> on a display <NUM>, and store data representing the electroanatomical map in a memory <NUM>. Memory <NUM> may include any suitable volatile and/or non-volatile memory, such as random-access memory or a hard disk drive.

In some embodiments, medical professional <NUM> can manipulate map <NUM> using one or more input devices <NUM>. In alternative embodiments, display <NUM> may include a touchscreen that can be configured to accept inputs from medical professional <NUM>, in addition to presenting map <NUM>.

<FIG> is a schematic pictorial illustration showing a perspective view of a medical probe <NUM> with a basket assembly <NUM> in an expanded form when unconstrained, such as by being advanced out of an insertion tube lumen <NUM> at a distal end <NUM> of an insertion tube <NUM>. The medical probe <NUM> illustrated in <FIG> lacks the guide sheath illustrated in <FIG>. <FIG> is an exploded view of the medical probe <NUM> and basket assembly <NUM> once again showing the basket assembly <NUM> in an expanded form while <FIG> shows the basket assembly <NUM> in a collapsed form within the insertion tube <NUM> of the guide sheath. In the expanded form (<FIG> and <FIG>), the spine <NUM> forms a spherical spiral shape and in the collapsed form (<FIG>), the spine <NUM> is arranged generally along a longitudinal axis <NUM> of insertion tube <NUM>.

As shown in <FIG>, basket assembly <NUM> includes a single spine <NUM> that is attached to an end of a tubular shaft <NUM>. During a medical procedure, medical professional <NUM> can deploy basket assembly <NUM> by extending tubular shaft <NUM> from insertion tube <NUM> (shown in <FIG>) causing the basket assembly <NUM> to exit the insertion tube and transition to the expanded form. Spine <NUM> may have an elliptical (e.g., circular) or a rectangular (that may appear to be flat) cross-section, and include 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, electrodes <NUM> can be configured to deliver ablation energy (RF and/or IRE) to tissue in heart <NUM>. Additionally, or alternatively, the electrodes can also be used to determine the location of basket assembly <NUM> and/or to measure a physiological property such as local surface electrical potentials at respective locations on tissue in heart <NUM>. As described further herein, the electrodes <NUM> can be biased such that a greater portion of the electrode <NUM> faces outwardly from the basket assembly <NUM> such that the electrodes <NUM> deliver a greater amount of electrical energy outwardly away from the basket assembly <NUM> (i.e., toward the heart <NUM> tissue) than inwardly toward the basket assembly <NUM>.

Examples of materials ideally suited for forming electrodes <NUM> include gold, platinum, and palladium (and their respective alloys). These materials also have high thermal conductivity which allows the minimal heat generated on the tissue (i.e., by the ablation energy delivered to the tissue) to be conducted through the electrodes to the back side of the electrodes (i.e., the portions of the electrodes on the inner sides of the spines), and then to the blood pool in heart <NUM>.

As illustrated in <FIG>, the spine <NUM> can form a generally spherical spiral shape when in an expanded form. For example, the spine <NUM> can have a first end that is disposed proximate the distal end of the tubular shaft <NUM> and a second end that is positioned proximate a distal end <NUM> of the medical probe <NUM> (i.e., the second end of the spine <NUM> can be the distal end <NUM> of the medical probe <NUM> when the basket assembly <NUM> is in the expanded form). When in the expanded form, the spine <NUM> can spiral outwardly from the first end to a first location along the spine that is between the first end and the second end. The spine <NUM> can spiral inwardly from the first location to the second end to complete the spherical spiral shape.

The electrodes <NUM> can be spaced along the spine <NUM> such that the electrodes <NUM> are configured to face outwardly and are positioned to contact, or nearly contact, the cardiac tissue when the basket assembly <NUM> is in the expanded form. In this way, the basket assembly <NUM> can be configured to position the electrodes <NUM> to facilitate the IRE ablation procedure. For example, the electrodes <NUM> can be spaced along the spine <NUM> such that an electrode disposed along a first turn of the spiral can be offset in relation to a second electrode <NUM> that is disposed along a second turn of the spiral. In other words, the electrodes <NUM> can be offset from an adjacent electrode <NUM> to ensure the basket assembly <NUM> is able to sufficiently deliver electrical pulses to the cardiac tissue.

<FIG> is a schematic pictorial illustration showing an exploded side view of a medical probe <NUM> in an expanded form, in accordance with the disclosed technology. As illustrated in <FIG>, the spine <NUM> can be a spiral shape such that a periphery of the basket assembly <NUM> forms a generally spherical shape when in an expanded form. The spine <NUM> can be configured to form the generally spherical shape with a predetermined diameter D when in the expanded form. The diameter D can be sized to ensure the basket assembly <NUM> can fit within a chamber of the heart and so that the electrodes <NUM> are sufficiently spaced to perform the IRE ablation procedure. The spine <NUM> can also be configured such that the periphery of the basket assembly <NUM> forms an oblate-spheroid shape when in an expanded form such that a distance between a proximal end and a distal end of the basket <NUM> is closer together when compared to the spherically-shaped basket. The oblate-spheroid shape can have the same diameter D as that of the spherical shape and be sized to ensure the basket assembly <NUM> can fit within a chamber of the heart and so that the electrodes <NUM> are sufficiently spaced to perform the IRE ablation procedure.

The medical probe <NUM> can include a spine retention hub <NUM> disposed proximate the distal end <NUM> of the tubular shaft <NUM>. The spine retention hub <NUM> can be inserted into the tubular shaft <NUM> and attached to the tubular shaft <NUM>. The spine retention hub <NUM> can include a cylindrical member comprising a relief land <NUM> disposed on the outer surface of the cylindrical member to allow the spine <NUM> to be fitted into the relief land <NUM> and retained therein. For example, the spine retention hub <NUM> can include a relief land <NUM> that is sized to receive an attachment end <NUM> of the spine <NUM>. The attachment end <NUM> can be a generally linear end of the spine <NUM>. The attachment end <NUM> can be configured to extend outwardly from the spine retention hub <NUM> such that the basket assembly <NUM> is positioned outwardly from the spine retention hub <NUM> and, consequently, outwardly from the tubular shaft <NUM>. In this way, the spine <NUM> can be configured to position the basket assembly <NUM> distally from the distal end of the tubular shaft <NUM> and distal from the distal end of the insertion tube <NUM> when the basket assembly is deployed. The spine retention hub <NUM> can further include at least one electrode <NUM> disposed at a distal portion of the spine retention hub <NUM>. Electrode <NUM> disposed at a distal end of retention hub <NUM> can be used in combination with electrodes <NUM> on the spines <NUM>, or alternatively, can be used independently from electrodes <NUM> for reference mapping or ablation.

As described supra, control console <NUM> includes irrigation module <NUM> that delivers irrigation fluid to distal end <NUM>. Spine retention hub <NUM> can include one or more irrigation openings <NUM>, wherein each given irrigation opening <NUM> can be angled to spray or otherwise disperse of the irrigation fluid to either a given electrode <NUM> or to tissue in heart <NUM>. Since electrodes <NUM> do not include irrigation openings that deliver irrigation fluid, the configuration described herein enables heat to be transferred from the tissue (i.e., during an ablation procedure) to the portion of the electrodes on the inner side of the spine <NUM>, and the electrodes <NUM> can be cooled by aiming the irrigation fluid, via irrigation openings <NUM>, at the portion of the electrodes <NUM> on the inner side of the spine <NUM>.

<FIG> is a schematic pictorial illustration showing a side view of a medical probe <NUM> in a collapsed form, in accordance with the disclosed technology. As illustrated in <FIG>, the basket assembly <NUM> can be pulled into the flexible insertion tube <NUM> such that the spine <NUM> is disposed generally linearly along a longitudinal axis <NUM> of the medical probe <NUM> when in the collapsed form. In other words, when the tubular shaft <NUM> is pulled into the flexible insertion tube <NUM>, the basket assembly <NUM> can be pulled along into the flexible insertion tube <NUM>. Because the basket assembly <NUM> comprises a spine <NUM> being made from a flexible resilient material, the basket assembly <NUM> can be elongated such that the spine <NUM> (and necessarily basket assembly <NUM>) is disposed generally linearly along the longitudinal axis <NUM> of the medical probe <NUM>. As will be appreciated, however, because the spine <NUM> comprises a flexible resilient material, the spine <NUM> may not form a completely straight configuration but may include various bends or curves when pulled into the flexible insertion tube <NUM>.

<FIG> is a schematic pictorial illustration of a method of forming a spine <NUM> from a planar sheet of resilient material <NUM>, in accordance with the disclosed technology. The spine <NUM> can be formed by cutting a first spiral 214A and a second spiral 214B into the planar sheet of resilient material <NUM> (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 can be attached to each other with a linear portion 214C. The first spiral 214A and the second spiral 214B can each have a diameter D that are equal in size. The linear portion 214C can 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 of resilient material <NUM>, the spine <NUM> can 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 can be expanded in a first direction to form a three-dimensional spiral, the second spiral 214B can be expanded in a second direction to form a second three-dimensional spiral, and the linear portion 214C can be coiled or rounded between the first and second spirals 214A, 214B to complete the spherical spiral. The spine <NUM> can be bent to retain the spherical spiral shape. Alternatively, or in addition, the spine <NUM> can be heat treated to retain the spherical spiral shape. As well, the spine assembly 210A or 210B can be formed by laser cutting a cylindrical hollow stock material whereby the laser is mounted for rotation about the longitudinal axis (and translation thereto) of the cylindrical stock while cutting through the cylindrical stock. As will be appreciated, the methods described are offered merely for illustrative purposes and should not be construed as limiting.

<FIG> is a schematic pictorial illustration of a method of forming at least a portion of a spine <NUM> from a cylindrical hollow tube of resilient material <NUM>, in accordance with the disclosed technology. As illustrated in <FIG>, the spine <NUM> can be formed from a cylindrical hollow tube of resilient material <NUM> (e.g., a shape-memory alloy such as nickel-titanium (also known as Nitinol), cobalt chromium, or any other suitable material) by cutting the cylindrical hollow tube of resilient material <NUM> into spiral sections. For example, by starting at one end of the cylindrical hollow tube of resilient material <NUM> and cutting the cylindrical hollow tube of resilient material <NUM> at an angle, a spiral section of the cylindrical hollow tube of resilient material <NUM> can be formed. The spine <NUM> can be cut, for example, by spinning the cylindrical hollow tube of resilient material <NUM> and moving a knife, laser, or other cutting device longitudinally along the length of the cylindrical hollow tube of resilient material <NUM>. Alternatively, the cylindrical hollow tube may be kept stationary while the cutting devices is rotated about the cylindrical hollow tube.

After cutting the spine <NUM> from the cylindrical hollow tube of resilient material <NUM>, the spine <NUM> can be formed into a spherical spiral by bending the spine <NUM> into the spherical spiral shape. The spine <NUM> can retain the spherical spiral shape simply by being bent into the spherical spiral shape. Alternatively, or in addition, the spine <NUM> can be heat treated to retain the spherical spiral shape. As will be appreciated, the method just described is offered merely for illustrative purposes and should not be construed as limiting.

Alternatively, or in addition, the spine <NUM> can be formed by coiling round wire, flat wire, coined flat wire, or other similar types of wire or material to form the spherical spiral. For example, the spine <NUM> can be formed by bending a round wire (or other selected wire type) until the desired spherical spiral shape is achieved.

Referring back to <FIG>, one or more electrodes <NUM> can be attached to spines <NUM> to form the basket assembly <NUM>. In some examples, each electrode <NUM> can include electrically conductive material (e.g., gold, platinum and palladium (and their respective alloys)). Turning to <FIG>, electrode <NUM> can have a variety of cross-sectional shapes, curvatures, lengths, lumen number and lumen shape as provided as examples in electrodes 740A-740E. The electrodes 740A-740E are offered to illustrate various configurations of electrodes <NUM> that can be used with the medical device <NUM> but should not be construed as limiting. One skilled in the art will appreciate that various other configurations of electrodes <NUM> can be used with the disclosed technology without departing from the scope of this disclosure.

Each electrode 740A-740E can have an outer surface <NUM> facing outwardly from electrode <NUM> and an inner surface <NUM> facing inwardly toward electrode <NUM> where at least one lumen <NUM> is formed through electrode <NUM>. The lumen <NUM> can be sized and configured to receive a spine <NUM> such that spine <NUM> can pass through electrode <NUM>. Lumen <NUM> can be a symmetric opening through electrode 740A-740E and can be disposed offset with respect to a longitudinal axis L-L of the respective electrode. In other examples, lumen <NUM> can pass through electrode <NUM> in a generally transverse direction with respect to the longitudinal axis L-L of the respective electrode. Furthermore, lumen <NUM> can be positioned in electrode <NUM> nearer a bottom surface, nearer a top surface, or nearer a middle of electrode <NUM> depending on the particular configuration. In <FIG>, and <FIG>, 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 between the top surface and the bottom surface. In other words, each electrode 740A-740E can include a lumen <NUM> that is offset with respect to a centroid of the electrode 740A-740E.

In addition, as shown in <FIG>, electrodes 740A-740C can have a wire relief <NUM> forming a recess or depression in electrode <NUM> adjacent lumen <NUM> for one or more wires to pass through lumen <NUM> along with a respective spine <NUM>. Relief <NUM> can be sized to provide room for a wire of electrode <NUM> to pass through electrode <NUM> such that electrode <NUM> can be in electrical communication with the control console <NUM>.

Alternatively, or in addition thereto, wires can pass through a wire lumen <NUM> as shown in example electrodes 740D and 740E in <FIG>. Although not depicted, electrodes <NUM> may include both a wire relief <NUM> adjacent lumen <NUM> and wire lumen <NUM>. Such electrode may permit additional wires to pass through the electrode body.

As shown in <FIG>, the electrodes 740A-740E can include various shapes depending on the application. For example, as illustrated in <FIG>, the electrode 740A can comprise a substantially rectangular cuboid shape with rounded edges. In other examples, the electrode 740B can comprise a substantially ovoid shape (as illustrated in <FIG>), the electrode 740C, 740D can have a contoured shape having a convex side and a concave side (as illustrated in <FIG>), or the electrode 740E can have a contoured shape having substantially more material proximate an upper side than a lower side of the electrode 740E (as illustrated in <FIG>). As will be appreciated by one of skill in the art, the various example electrodes 740A-740E shown in <FIG>, and described herein, are offered for illustrative purposes and should not be construed as limiting.

<FIG> are schematic pictorial illustrations showing various insulative jackets 880A, 880B of a given medical device <NUM>, in accordance with embodiments of the present invention. <FIG> is a front view while <FIG> is a perspective view of insulative jackets 880A, 880B. Insulative jackets 880A, 880B can be made from a biocompatible, electrically insulative material such as polyamide-polyether (Pebax) copolymers, polyethylene terephthalate (PET), urethanes, polyimide, parylene, silicone, etc. In some examples, insulative material can include biocompatible polymers including, without limitation, polyetheretherketone (PEEK), polyglycolic acid (PGA), poly(lactic-co-glycolic acid) copolymer (PLGA), polycaprolactive (PCL), poly(<NUM>-hydroxybutyrate-co-<NUM>-hydroxyvalerate) (PHBV), poly-L-lactide, polydioxanone, polycarbonates, and polyanhydrides with the ratio of certain polymers being selected to control the degree of inflammatory response. Insulative jackets 880A, 880B may also include one or more additives or fillers, such as, for example, polytetrafluoroethylene (PTFE), boron nitride, silicon nitride, silicon carbide, aluminum oxide, aluminum nitride, zinc oxide, and the like. Insulative jacket 880A, 880B can help to insulate a spine <NUM> and/or wires passing through insulative jacket 880A, 880B from electrode <NUM> to prevent arcing from electrode <NUM> to the spine <NUM> and/or mechanical abrasion of wires passing through insulative jacket 880A, 880B.

As illustrated in <FIG>, insulative jackets 880A, 880B, can include a cross-sectional shape that is substantially trapezoidal. The insulative jacket may consist of a single lumen or multi-lumen configuration. Multi-lumen jackets may be configured such that the alloy frame and wires share a single lumen while the second lumen may be used for irrigation. The alloy frame and wires may occupy separate lumens, also, as described. For these designs, the insulative jackets may be continuous (individual sleeves extending from proximal to distal end of each alloy frame strut), segmented (bridging between electrode gaps), or a combination of both. Furthermore, insulative jacket 880A, 880B can include a first lumen 882A, 882B and a second lumen 884A, 884B. First lumen 882A, 882B can be configured to receive spine <NUM> while second lumen 884A, 884B can be configured to receive a wire, or vice-versa. In other examples, first lumen 882A, 882B and second lumen 884A, 884B can each be configured to receive one or more wires that can be connected to one or more electrodes <NUM>. Furthermore, as illustrated in <FIG>, insulative jacket 880A, 880B can include an aperture 886A, 886B through which a wire can be electrically connected to electrode <NUM>. Although illustrated in <FIG> as being proximate a bottom of insulative jacket 880A, 880B, aperture 886A, 886B can be positioned proximate a top or side of insulative jacket 880A, 880B. Furthermore, insulative jacket 880A, 880B can include multiple apertures 886A, 886B with each aperture being disposed on the same side of insulative jacket (i.e., top, bottom, left, right) or on different sides of the insulative jacket depending on the application.

<FIG> are schematic pictorial illustrations showing cross-sectional views of a given wire <NUM>, <NUM> that can be connected to a given electrode <NUM>, in accordance with an embodiment of the present invention. <FIG> illustrates a solid core wire <NUM>. <FIG> illustrates a stranded wire <NUM>. Each wire <NUM>, <NUM> can extend through at least a portion of the tubular shaft <NUM>. Solid core wire <NUM> can include an electrically conductive core material <NUM> and an electrically conductive cover material <NUM> circumscribing electrically conductive core material <NUM>. Likewise, stranded wire <NUM> can include strands each including an electrically conductive core material <NUM> and an electrically conductive cover material <NUM> circumscribing the electrically conductive core material <NUM>. Each wire <NUM>, <NUM> can include an insulative jacket <NUM> circumscribing the conductors. The wires <NUM>, <NUM> can be configured to withstand a voltage difference of adjacent wires sufficient to deliver IRE pulses. Preferably, the wires <NUM>, <NUM> can withstand at least 900V to 2000V, and more preferably at least <NUM>,800V to 4000V between adjacent wires. To reduce likelihood of dielectric breakdown between conductors of adjacent wires, electrically conductive cover material <NUM>, <NUM> can have a lower electrical conductivity compared to core material <NUM>, <NUM>.

Insulative jacket <NUM> can be configured to have a temperature rating between <NUM> and <NUM> degrees Centigrade so that the electrically insulative jacket <NUM> melts or degrades (e.g., chars and crumbles) during soldering of wire <NUM> to electrodes <NUM> (e.g., at a temperature of <NUM> degrees Centigrade) and therefore insulative jacket <NUM> of wire <NUM> does not need to be mechanically stripped. In other examples, insulative jacket <NUM> can have a temperature rating greater than <NUM> degrees Centigrade to prevent electrically insulating material <NUM> melting or degrading (e.g., charring and crumbling) during manufacture of medical probe <NUM> and/or during use. Insulative jacket <NUM> can be mechanically stripped from wire <NUM> prior to wires <NUM> being electrically connected to electrodes <NUM>.

<FIG> is a flowchart illustrating a method <NUM> of assembling a basket assembly <NUM>, in accordance with an embodiment of the present invention. The method <NUM> can include cutting <NUM> a planar sheet of resilient material to form two connected spirals (e.g., as explained in relation to <FIG>). The planar sheet of resilient material can include shape-memory alloy such as nickel-titanium (also known as Nitinol), cobalt chromium, or any other suitable material. The method <NUM> can include forming <NUM> a spine having a spherical spiral shape from the two connected spirals. The two spirals can be connected with a linear portion. The method <NUM> can further include inserting <NUM> the spine into a lumen of one or more electrodes and fitting <NUM> an end of the spine into a tubular shaft sized to traverse vasculature. As will be appreciated by one of skill in the art having the benefit of this disclosure, fitting <NUM> an end of the spine into a tubular shaft can include attaching the spine <NUM> to a spine retention hub <NUM>. Furthermore, the spine retention hub <NUM> and/or the spine <NUM> and the tubular shaft <NUM> can be inserted into a flexible insertion tube <NUM> to form the medical probe <NUM>.

<FIG> is a flowchart illustrating another method <NUM> of assembling a basket assembly <NUM>, in accordance with an embodiment of the present invention. The method <NUM> can include cutting <NUM> a cylindrical hollow tube of resilient material to form a spiral (e.g., as explained in relation to <FIG>). The method <NUM> can include forming <NUM> the spine to have a spherical spiral shape from the spiral, inserting <NUM> the spine into a lumen of one or more electrodes, and fitting <NUM> an end of the spine into a tubular shaft sized to traverse vasculature. As with method <NUM>, fitting <NUM> an end of the spine into a tubular shaft can include attaching the spine <NUM> to a spine retention hub <NUM>. Furthermore, the spine retention hub <NUM> and/or the spine <NUM> and the tubular shaft <NUM> can be inserted into a flexible insertion tube <NUM> to form the medical probe <NUM>.

<FIG> is a flowchart illustrating another method <NUM> of assembling a basket assembly <NUM>, in accordance with an embodiment of the present invention. The method <NUM> can include coiling <NUM> an elongated piece of resilient material to form a spine having a spherical spiral shape. The method <NUM> can include inserting <NUM> the spine into a lumen of one or more electrodes and fitting <NUM> an end of the spine into a tubular shaft size to traverse vasculature. As before, fitting <NUM> an end of the spine into a tubular shaft can include attaching the spine <NUM> to a spine retention hub <NUM>. Furthermore, the spine retention hub <NUM> and/or the spine <NUM> and the tubular shaft <NUM> can be inserted into a flexible insertion tube to form the medical probe <NUM>.

Examples are described below which can be used separately or in various permutations with each other.

As will be appreciated by one skilled in the art, the methods <NUM>, <NUM>, and <NUM> just described can include any of the various features of the disclosed technology described herein and can be varied depending on the particular configuration. Thus, the methods <NUM>, <NUM>, and <NUM> should not be construed as limited to the particular steps and order of steps explicitly described herein.

Claim 1:
A medical probe (<NUM>), comprising:
a tubular shaft (<NUM>) having a proximal end and a distal end, the tubular shaft extending along a longitudinal axis;
an expandable basket assembly (<NUM>) proximate the distal end of the tubular shaft, the expandable basket assembly comprising:
a single spine (<NUM>) comprising a resilient material extending generally linearly along the longitudinal axis (<NUM>) in a collapsed form and forming a spiral member defining a generally spherical outer periphery in an expanded form; and
one or more electrodes (<NUM>, 740A-740E) coupled to the single spine,
characterised in that each electrode comprises a lumen (<NUM>) offset with respect to a centroid of the electrode so that the single spine extends through the lumen of each of the one or more electrodes.