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> discloses methods and apparatuses for ablative modulation of nerves through the walls of blood vessels. <CIT> discloses systems and methods for mapping and ablating the interior regions of the heart.

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, tripodic structures including three spines are generally assembled together by attaching ends of the three 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 two or more tripodic structures 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 help to reduce the time required for manufacturing the basket assembly and alternative basket assembly geometries in general.

Various embodiments of a medical probe and related methods are described and illustrated. The medical probe may include a tubular shaft, an expandable basket assembly, and one or more electrodes. The tubular shaft can have a proximal end and a distal end. The tubular shaft can extend along a longitudinal axis. The expandable basket assembly can be proximate the distal end of the tubular shaft. The basket assembly can include a first unitary tripodic structure and a second unitary tripodic structure. Each tripodic structure can be formed from a respective planar sheet of material that includes three linear spines converging at a respective central spine intersection. Each spine of each tripodic structure can have a respective end connected to the distal end of the tubular shaft. The central spine intersection of each tripodic structure can be positioned on the longitudinal axis at a distal end of the basket assembly. The one or more electrodes can be coupled to each of the spines. Each electrode can define a lumen through the electrode so that the spine extends through the lumen of each of the one or more electrodes.

The disclosed technology can include a method of constructing a medical probe. The method can include cutting a first sheet of planar material to form a first structure comprising three spines including a first central spine intersection; cutting a second sheet of planar material to form a second structure comprising three spines including a second central spine intersection; overlapping the central spine intersections of the first and second structures; inserting each spine of the respective structure into a lumen of at least electrode; and fitting ends of the spines of the respective structure to a tubular shaft sized to traverse vasculature such that the central spine intersections are positioned at a distal end of the medical probe and respective spines are movable from a tubular configuration to a bowed configuration.

As used herein, the terms "patient," "host," "user," and "subject" refer to any human or animal subject and are not intended to limit the systems or methods to human use, although use of the subject invention in a human patient represents a preferred embodiment. In addition, 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 well, 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, "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 including a high current density and high electric flux density is positioned at a treatment site, and a second electrode including 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 including 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 including 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 including 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 including 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 entirety of which is incorporated herein by reference and attached in the appendix to priority application <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 including proximal and distal ends, and a basket assembly at the distal end of the tubular shaft. The basket assembly includes at least one tripodic structure including three linear spines converging at a central intersection and including one or more electrodes coupled to each of the spines. The linear spines can bend to form an approximately spherical or oblate-spheroid basket assembly.

<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 CARTO® 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 tubular shaft. 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 <NUM>, as described in the description referencing <FIG> 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 including peak power in the range of tens of kilowatts. In some examples, the electrodes <NUM> are configured to deliver electrical pulses including 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 tubular shaft <NUM> (see <FIG>). Irrigation may be utilized in some instances to reduce blood clot formations or blood pooling near the ablation electrodes or even to transfer any heat generated in the electrodes during ablation. 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> are schematic pictorial illustrations showing a perspective view of a medical probe <NUM> including 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 probes <NUM> illustrated in <FIG> lack the guide sheath illustrated in <FIG>. <FIG> shows the basket assembly a collapsed form within insertion tube <NUM> of the guide sheath. In the expanded form (<FIG>), spines <NUM> bow radially outwardly and in the collapsed form (<FIG>) the spines are arranged generally along a longitudinal axis <NUM> of insertion tube <NUM>.

As shown in <FIG>, basket assembly <NUM> includes a first unitary tripodic structure 213A including three spines <NUM> formed from a planar sheet of reliant and flexible material that allows for bending of the spines to form basket assembly <NUM> at the 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> causing basket assembly <NUM> to exit insertion tube <NUM> and transition to the expanded form. Spines <NUM> may have elliptical (e.g., circular) or rectangular (that may appear to be flat) cross-sections, and include a flexible, resilient material (e.g., a shape-memory alloy such as nickel-titanium, also known as Nitinol) forming a strut as will be described in greater detail herein.

As shown in <FIG>, the first unitary tripodic structure 213A includes three linear spines <NUM> that converge at a first central spine intersection <NUM>1A. In some examples the first central spine intersection 211A can include one or more cutouts <NUM> that alter the flexibility of the tripodic structure <NUM> and allow for more bending of the spines <NUM>. It is noted that the cutouts (in various configurations described and illustrated in the specification allows for a much smaller form factor when undeployed (or undergoing a retraction into a delivery sheath) without buckling or plastic deformation.

As shown in <FIG>, basket assembly <NUM> can include first unitary tripodic structure 213A and a second unitary tripodic structure 213B, similarly including three linear spines <NUM> converging at the central spine intersection (the second central spine intersection 211B). Second central spine intersection 211B can include one or more cutouts <NUM> similar to first central spine intersection 211A, as depicted in <FIG>, but in some examples, the first or second central spine intersections 211A, 211B can be solid (no cutouts) or present cutouts on only one tripodic structure 213A, 213B.

In embodiments described herein, one or more electrodes <NUM> positioned on spines <NUM> of basket assembly <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>. The electrodes <NUM> can be biased such that a greater portion of the one or more electrodes <NUM> face outwardly from basket assembly <NUM> such that the one or more 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.

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>.

Turning to <FIG>, basket assembly <NUM> includes a first unitary tripodic structure 213A including three linear spines <NUM> formed from a planar sheet of material <NUM>, 210A (shown more clearly in <FIG> and <FIG>). <FIG> shows basket assembly <NUM> including a second unitary tripodic structure 213B overlapping first tripodic structure 213A. Although now shown, basket assembly <NUM> can include more than two unitary tripodic structures.

In any embodiment disclosed herein, the spines on each tripodic structures 213A, 213B can have respective spine attachment ends <NUM> that are configured to couple to the distal end of the tubular shaft <NUM> and/or a spine retention hub <NUM> disposed within tubular shaft <NUM>. 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>. Spine retention hub <NUM> can include a cylindrical member <NUM> including a plurality of relief lands <NUM>, multiple irrigation openings <NUM>, and at least one spine retention hub electrode <NUM>. Relief lands <NUM> can be disposed on the outer surface of cylindrical member <NUM> and configured to allow at least a portion of each spine <NUM>, such as each spine attachment end <NUM>, to be fitted into a respective relief land <NUM>. The attachment end <NUM> can be a generally linear end of the spine <NUM>. The attachment end <NUM> can be configured to extend distally from the spine retention hub <NUM> such that the basket assembly <NUM> is positioned distally from the spine retention hub <NUM> and, consequently, distally 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.

As described supra, control console <NUM> includes irrigation module <NUM> that delivers irrigation fluid to distal end <NUM>. The multiple irrigation openings <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 hereinabove 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 spines <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 spines <NUM>. Spine retention hub 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.

<FIG> are schematic pictorial illustrations showing a profile outline of spines <NUM> of a basket assembly 38A, 38B of a given medical device <NUM>, in accordance with embodiments of the present invention. To illustrate, the basket assembly can have a profile as shown in <FIG> that is approximately circular to form an approximately spherical shape when basket assembly 38A is in the expanded form. As another example, the basket assembly can have a profile as shown in <FIG> that is an approximately elliptical shape to form an approximately oblate-spheroid shape when basket assembly 38B is in the expanded form. Although not every variation of shape is shown or described herein, one skilled in the art will appreciate that spines <NUM> can be further configured to form other various shapes as would be suitable for the particular application.

By including spines <NUM> configured to form various shapes when in the expanded form, basket assembly <NUM> can be configured to position the various electrodes <NUM> attached to spines <NUM> at various locations, with each location being nearer or farther from the distal end of tubular shaft <NUM>. For example, electrode <NUM> attached to spine <NUM> illustrated in <FIG> near the middle of spine <NUM> would be farther from the distal end of tubular shaft <NUM> than spine <NUM> illustrated in <FIG> when basket assembly <NUM> is in the expanded form. In addition, each spines <NUM> may have an elliptical (e.g., circular) or 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).

<FIG>, <FIG> are schematic pictorial illustrations showing views of first structure 213A forming basket assembly <NUM> (<FIG>) and both first and second structures 213A, 213B forming basket assembly <NUM> (<FIG>). In particular, <FIG> provides one example of how planar sheet of material <NUM> may be assembled together with tubular shaft <NUM> whereby each spine <NUM> bends or curves when respective attachment ends <NUM> are connect to spine retention hub <NUM>. As shown in <FIG>, first structure 213A can be overlapped with second structure 213B, both formed from a single sheet of planar material 210A, 210B, to form a generally three-star structure when laid flat. In other words, spines <NUM> of each first and second structure 213A, 213B can be formed from the single planar sheet of material such that the spines <NUM> converge toward a respective central intersection 211A, 211B. Central intersection 211A, 211B can be a solid piece of material (as shown in <FIG>) or include a cutout <NUM> (as shown in <FIG>). Basket assembly <NUM> can include a number of structures including three spines. As would be appreciated by those of skill in the relevant art, overlapping additional structures including three formed from planar sheets of material can alter flexibility of basket assembly <NUM> and increase the number of electrodes <NUM>.

<FIG> are schematic pictorial illustrations of top-down views of basket assembly <NUM>, showing various examples of central intersection <NUM> one or more cutouts <NUM>. As shown, intersection <NUM> can include a single discrete cutout <NUM>. Although not shown, intersection <NUM> can also include two or more cutouts. The one or more cutouts <NUM> can include a variety of patterns, such as centrosymmetric (i.e., symmetric with respect to a central point), and equiangular (i.e., including equal angles) to allow for equal bending among the spines <NUM> as well as disproportional and asymmetric to allow for unequal bending of spines <NUM> to alter structural stability. In certain instances, when basket assembly <NUM> includes more than first structure 213A, basket assembly <NUM> will include more than one cutout <NUM>, as shown in <FIG>. In any of the embodiments described herein, cutout <NUM> can extend along a portion of each spine <NUM>.

The spines <NUM> can be folded or otherwise bent such that each respective attachment end <NUM> of the spine <NUM> can be inserted into the distal end <NUM> of the tubular shaft <NUM> and relief lands <NUM> of spine retention hub <NUM>. Although not shown in <FIG>, it will be appreciated that electrodes <NUM> can be attached to spines <NUM> before the spines are inserted into the tubular shaft <NUM> to form the basket assembly <NUM>. As stated previously, the spines <NUM> can include a flexible, resilient material (e.g., a shape-memory alloy such as nickel-titanium, also known as Nitinol) that can enable the basket assembly <NUM> to transition to its expanded form (as shown in <FIG>) when the basket assembly <NUM> is deployed from tubular shaft <NUM>. As will become apparent throughout this disclosure, spines <NUM> can be electrically isolated from electrode <NUM> to prevent arcing from electrode <NUM> to the respective spine <NUM>.

As will be appreciated by one skilled in the art with the benefit of this disclosure, basket assembly <NUM> shown in <FIG> including spines <NUM> formed from a planar sheet of material and converging at a central intersection is offered merely for illustrative purposes and the disclosed technology can be applicable to other configurations of basket assemblies <NUM>. For example, the disclosed technology can be applicable to basket assemblies <NUM> formed from a single spine <NUM> or multiple spines <NUM> with each spine <NUM> being attached at both ends. In other examples, the basket assembly <NUM> can include a retention hub connecting the multiple spines <NUM> together at a distal end <NUM> of the basket assembly <NUM>. In yet other examples, the basket assembly <NUM> can include a single spine <NUM> configured to form a spiral, multiple spines <NUM> configured to form a spiral, multiple spines <NUM> configured to form a tripod or multiple tripods, or any other shape of basket assembly <NUM>. Thus, although <FIG> illustrate a specific configuration of basket assembly <NUM>, the disclosed technology should not be construed as so limited.

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 (upper side) is oriented toward the top of the drawing, the bottom surface (lower side) 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 electrode740A-740E.

In addition, as shown in <FIG>, electrodes 740A-740E 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-740C can include various shapes depending on the application. For example, as illustrated in <FIG>, the electrode 740A can have a substantially rectangular cuboid shape with rounded edges. In other examples, the electrode 740B can have a substantially ovoid shape (as illustrated in <FIG>), the electrode 740C, 740D can have a contoured shape including a convex side and a concave side (as illustrated in <FIG>), or the electrode 740E can have a contoured shape including 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>. <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. 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. The current embodiment does not utilize irrigated jackets. 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 tubular shaft <NUM> and 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, and more preferably at least <NUM>,800V 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> are schematic pictorial illustrations of cutting tripodic structure patterns <NUM> from a planar sheet of material <NUM> including three linear spines. As described supra, planar sheet of material <NUM> can include three spines <NUM>. As illustrated in <FIG>, planar sheet of material <NUM> can include central intersection <NUM> and a spine pattern 1002A, which include one or both of longitudinal scores <NUM> and transverse scores <NUM>. In any of the embodiments disclosed herein, planar sheet of material <NUM> can also include an equiangular pattern <NUM> between spines. <FIG> provides an example spine patterns 1002B including one or more cutout patterns 1002B to form one or more cutouts <NUM> on central intersection <NUM>.

<FIG> is a flowchart illustrating a method <NUM> of manufacturing a basket assembly <NUM>, in accordance with an embodiment of the present invention. Method <NUM> can include cutting <NUM> a first sheet of planar material 210A to form a first structure 213A including three spines <NUM> including a first central spine intersection 211A. Method <NUM> can include cutting <NUM> a second sheet of planar material 210B to form a second structure 213B including three spines <NUM> including a second central spine intersection 211B. Cutting <NUM>, <NUM> the first and second structures 213A, 213B can include cutting from a pattern 1002A, 1002B including longitudinal and transverse scores <NUM>, <NUM> from the planar sheet of material <NUM>. The planar sheet of material can include resilient, shape-memory alloy such as nickel-titanium (also known as Nitinol), cobalt chromium, or any other suitable material. Method <NUM> can include overlapping <NUM> the central spine intersections 211A, 211B of the first and second structures 213A, 213B. Method <NUM> can include inserting <NUM> each spine into a lumen <NUM> of at least one electrode <NUM>. The electrodes can be positioned such that the electrodes are offset between electrodes on adjacent spines. Method <NUM> can include fitting <NUM> ends of the spines <NUM> of the respective structure 213A, 213B to a tubular shaft <NUM> sized to traverse vasculature such that the central spine intersections are positioned at a distal end <NUM> of the medical probe <NUM> and respective spines <NUM> are movable from a tubular configuration to a bowed configuration. As will be appreciated by one of skill in the art including 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>. Method <NUM> can end at step <NUM> or can also further include cutting a discrete cutout <NUM> at one or both of the central spine intersections 211A, 211B. As described supra, the discrete cutout <NUM> can be a single cutout or two or more cutouts. In addition, the one or more discrete cutouts can be cut in a pattern to extend along at least a portion of each spine. Method <NUM> can end after fitting <NUM> ends of the spines into the tubular shaft <NUM> or can further include electrically connecting the wire to the one or more electrodes. Method <NUM> can also include disposing an insulative sleeve over the spines and within the lumen of the respective electrode.

Claim 1:
A medical probe (<NUM>), comprising:
a tubular shaft (<NUM>) including a proximal end and a distal end, the tubular shaft extending along a longitudinal axis (<NUM>);
an expandable basket assembly (<NUM>) proximate the distal end of the tubular shaft, the basket assembly comprising a first unitary tripodic structure (213A) and a second unitary tripodic structure (213B), each tripodic structure formed from a respective planar sheet of material that includes three linear spines (<NUM>) converging at a respective central spine intersection (211A, 211B), each spine of each tripodic structure including a respective end connected to the distal end of the tubular shaft, the central spine intersection of each tripodic structure being positioned on the longitudinal axis at a distal end of the basket assembly; and
one or more electrodes (<NUM>, 740A-740E) coupled to each of the spines, each electrode defining a lumen (<NUM>) through the electrode so that the spine extends through the lumen of each of the one or more electrodes.