Patent Description:
It is generally known that ablation therapy may be used to treat various conditions afflicting the human anatomy. For example, ablation therapy may be used in the treatment of atrial arrhythmias. When tissue is ablated, or at least subjected to ablative energy generated by an ablation generator and delivered by an ablation catheter, lesions form in the tissue. Electrodes mounted on or in ablation catheters are used to create tissue necrosis in cardiac tissue to correct conditions such as atrial arrhythmia (including, but not limited to, ectopic atrial tachycardia, atrial fibrillation, and atrial flutter).

Arrhythmia (i.e., irregular heart rhythm) can create a variety of dangerous conditions including loss of synchronous atrioventricular contractions and stasis of blood flow which can lead to a variety of ailments and even death. It is believed that the primary cause of atrial arrhythmia is stray electrical signals within the left or right atrium of the heart. The ablation catheter imparts ablative energy (e.g., radiofrequency energy, cryoablation, lasers, chemicals, high-intensity focused ultrasound, etc.) to cardiac tissue to create a lesion in the cardiac tissue. This lesion disrupts undesirable electrical pathways and thereby limits or prevents stray electrical signals that lead to arrhythmias.

Electroporation is a non-thermal ablation technique that involves applying strong electric-fields that induce pore formation in the cellular membrane. The electric field may be induced by applying a relatively short duration pulse which may last, for instance, from a nanosecond to several milliseconds. Such a pulse may be repeated to form a pulse train. When such an electric field is applied to tissue in an in vivo setting, the cells in the tissue are subjected to trans-membrane potential, which opens the pores on the cell wall. Electroporation may be reversible (i.e., the temporally-opened pores will reseal) or irreversible (i.e., the pores will remain open). For example, in the field of gene therapy, reversible electroporation (i.e., temporarily open pores) is used to transfect high molecular weight therapeutic vectors into the cells. In other therapeutic applications, a suitably configured pulse train alone may be used to cause cell destruction, for instance by causing irreversible electroporation.

For example, pulsed field ablation (PFA) may be used to perform instantaneous pulmonary vein isolation (PVI). PFA generally involves delivering high voltage pulses from electrodes disposed on a catheter. For example, voltage pulses may range from less than about <NUM> volts to about <NUM> volts or higher. These fields may be applied between pairs of electrodes (bipolar therapy) or between one or more electrodes and a return patch (monopolar therapy).

<CIT> discloses systems, devices, and methods for delivery of pulsed electric field ablative energy to endocardial tissue. <CIT> discloses an electroporation system configured to apply a biphasic pulse signal to at least one electrode. US- <CIT> discloses expandable elements for delivery of electric fields.

The invention is defined in independent calim <NUM>. Preferred features are set out in the dependent claims. In one aspect, an apparatus for controlling an electroporation catheter is provided. The electroporation catheter includes a distal end, a proximal end, a plurality of splines extending from the distal end to the proximal end, and a plurality of electrodes arranged on the plurality of splines and defining at least one quadripolar array, each quadripolar array defined by four electrodes of the plurality of electrodes. The apparatus includes a pulse generator coupled to the electroporation catheter, and a computing device coupled to the pulse generator, the computing device operable to control the pulse generator to selectively energize the electrodes defining the at least one quadripolar array according to a first energization pattern, and selectively energize the electrodes defining the at least one quadripolar array according to a second energization pattern, wherein the first and second energization patterns are different from one another.

In another aspect, a method, which is not claimed as such, for controlling a system including an electroporation catheter, a pulse generator coupled to the electroporation catheter, and a computing device coupled to the pulse generator is provided. The electroporation catheter includes a distal end, a proximal end, a plurality of splines extending from the distal end to the proximal end, and a plurality of electrodes arranged on the plurality of splines and defining at least one quadripolar array, each quadripolar array defined by four electrodes of the plurality of electrodes. The method includes selectively energizing, using the computing device and the pulse generator, the electrodes defining the at least one quadripolar array according to a first energization pattern, and selectively energizing, using the computing device and the pulse generator, the electrodes defining the at least one quadripolar array according to a second energization pattern, wherein the first and second energization patterns are different from one another.

In yet another aspect, a system is provided. The system includes an electroporation catheter including a distal end, a proximal end, a plurality of splines extending from the distal end to the proximal end, and a plurality of electrodes arranged on the plurality of splines and defining at least one quadripolar array, each quadripolar array defined by four electrodes of the plurality of electrodes. The system further includes a pulse generator coupled to the electroporation catheter, and a computing device coupled to the pulse generator, the computing device operable to control the pulse generator to selectively energize the electrodes defining the at least one quadripolar array according to a first energization pattern, and selectively energize the electrodes defining the at least one quadripolar array according to a second energization pattern, wherein the first and second energization patterns are different from one another.

The foregoing and other aspects, features, details, utilities and advantages of the present disclosure will be apparent from reading the following description and claims, and from reviewing the accompanying drawings.

The systems and methods described herein are directed to an apparatus for controlling an electroporation catheter. The electroporation catheter includes a distal end, a proximal end, a plurality of splines extending from the distal end to the proximal end, and a plurality of electrodes arranged on the plurality of splines and defining at least one quadripolar array, each quadripolar array defined by four electrodes of the plurality of electrodes. The apparatus includes a pulse generator coupled to the electroporation catheter, and a computing device coupled to the pulse generator, the computing device operable to control the pulse generator to selectively energize the electrodes defining the at least one quadripolar array according to a first energization pattern, and selectively energize the electrodes defining the at least one quadripolar array according to a second energization pattern, wherein the first and second energization patterns are different from one another.

<FIG> is a schematic and block diagram view of a system <NUM> for electroporation therapy. In general, system <NUM> includes a catheter electrode assembly <NUM> disposed at a distal end <NUM> of a catheter <NUM>. As used herein, "proximal" refers to a direction toward the end of the catheter near the clinician and "distal" refers to a direction away from the clinician and (generally) inside the body of a patient. The electrode assembly includes one or more individual, electrically-isolated electrode elements. Each electrode element, also referred to herein as a catheter electrode, is individually wired such that it can be selectively paired or combined with any other electrode element to act as a bipolar or a multi-polar electrode.

System <NUM> may be used for irreversible electroporation (IRE) to destroy tissue. In particular, system <NUM> may be used for electroporation-induced therapy that includes delivering electrical current in such a manner as to directly cause an irreversible loss of plasma membrane (cell wall) integrity leading to its breakdown and cell necrosis. This mechanism of cell death may be viewed as an "outside-in" process, meaning that the disruption of the outside wall of the cell causes detrimental effects to the inside of the cell. Typically, for classical plasma membrane electroporation, electric current is delivered as a pulsed electric field in the form of short-duration pulses (e.g., having a <NUM> nanosecond (ns) to <NUM> microsecond (µs) duration) between closely spaced electrodes capable of delivering an electric field strength of about <NUM> to <NUM> kilovolts/centimeter (kV/cm). System <NUM> may be used with a grid catheter such as that depicted in <FIG>, for example, for high output (e.g., high voltage and/or high current) electroporation procedures. Alternatively, system <NUM> may be used with any suitable catheter configuration.

In one embodiment, all electrodes of the catheter deliver an electric current simultaneously. Alternatively, in other embodiments, stimulation is delivered selectively (e.g., between pairs of electrodes) on the catheter. For example, in some embodiments, the catheter includes a plurality of splines, each spline including a plurality of electrodes. In such embodiments, electrodes on one spline may be selectively activated, and electrodes on an adjacent (or other) spline function as an energy return (or sink). Further, in the embodiments described herein, the electrodes may be switchable between being connected to a 3D mapping system and being connected to an electroporation generator.

Irreversible electroporation through a multi-electrode catheter may enable pulmonary vein isolation in as few as one shock per vein, which may produce much shorter procedure times compared to sequentially positioning a radiofrequency (RF) ablation tip around a vein.

It should be understood that while the energization strategies are described as involving DC pulses, embodiments may use variations. For example, exponentially-decaying pulses, exponentially- increasing pulses, and combinations may be used.

Further, it should be understood that the mechanism of cell destruction in electroporation is not primarily due to heating effects, but rather to cell membrane disruption through application of a high-voltage electric field. Thus, electroporation may avoid some possible thermal effects that may occur when using radio frequency (RF) energy. This "cold therapy" thus has desirable characteristics.

With this background, and now referring again to <FIG>, system <NUM> includes a catheter electrode assembly <NUM> including at least one catheter electrode. Electrode assembly <NUM> is incorporated as part of a medical device such as a catheter <NUM> for electroporation therapy of tissue <NUM> in a body <NUM> of a patient. In the illustrative embodiment, tissue <NUM> includes heart or cardiac tissue. It should be understood, however, that embodiments may be used to conduct electroporation therapy with respect to a variety of other body tissues.

<FIG> further shows a plurality of return electrodes designated <NUM>, <NUM>, and <NUM>, which are diagrammatic of the body connections that may be used by the various sub-systems included in overall system <NUM>, such as an electroporation generator <NUM>, an electrophysiology (EP) monitor such as an ECG monitor <NUM>, and a localization and navigation system <NUM> for visualization, mapping, and navigation of internal body structures. In the illustrated embodiment, return electrodes <NUM>, <NUM>, and <NUM> are patch electrodes. It should be understood that the illustration of a single patch electrode is diagrammatic only (for clarity) and that such sub-systems to which these patch electrodes are connected may, and typically will, include more than one patch (body surface) electrode, and may include split patch electrodes (as described herein). In other embodiments, return electrodes <NUM>, <NUM>, and <NUM> may be any other type of electrode suitable for use as a return electrode including, for example, one or more catheter electrodes. Return electrodes that are catheter electrodes may be part of electrode assembly <NUM> or part of a separate catheter or device (not shown). System <NUM> may further include a main computer system <NUM> (including an electronic control unit <NUM> and data storage-memory <NUM>), which may be integrated with localization and navigation system <NUM> in certain embodiments. System <NUM> may further include conventional interface components, such as various user input/output mechanisms 34A and a display 34B, among other components.

Electroporation generator <NUM> is configured to energize the electrode element(s) in accordance with an electroporation energization strategy, which may be predetermined or may be user-selectable. For electroporation-induced primary necrosis therapy, generator <NUM> may be configured to produce an electric current that is delivered via electrode assembly <NUM> as a pulsed electric field in the form of short-duration DC pulses (e.g., a nanoseconds to several milliseconds duration, or any duration suitable for electroporation) between closely spaced electrodes capable of delivering an electric field strength (i.e., at the tissue site) of about <NUM> to <NUM> kV/cm. The amplitude and pulse duration needed for irreversible electroporation are inversely related.

Electroporation generator <NUM>, sometimes also referred to herein as a DC energy source, is a biphasic electroporation generator <NUM> configured to generate a series of DC energy pulses that all produce current in two directions. In other embodiments, electroporation generator is a monophasic or polyphasic electroporation generator. In some embodiments, electroporation generator <NUM> is configured to output energy in DC pulses at selectable energy levels, such as fifty joules, one hundred joules, two hundred joules, and the like. Other embodiments may have more or fewer energy settings and the values of the available setting may be the same or different. For successful electroporation, some embodiments utilize the two hundred joule output level. For example, electroporation generator <NUM> may output a DC pulse having a peak magnitude from about <NUM> Volts (V) to about <NUM>,<NUM> V at the two hundred joule output level. Other embodiments may output any other suitable positive or negative voltage.

In some embodiments, a variable impedance <NUM> allows the impedance of system <NUM> to be varied to limit arcing. Moreover, variable impedance <NUM> may be used to change one or more characteristics, such as amplitude, duration, pulse shape, and the like, of an output of electroporation generator <NUM>. Although illustrated as a separate component, variable impedance <NUM> may be incorporated in catheter <NUM> or generator <NUM>.

With continued reference to <FIG>, as noted above, catheter <NUM> may include functionality for electroporation and in certain embodiments also additional ablation functions (e.g., RF ablation). It should be understood, however, that in those embodiments, variations are possible as to the type of ablation energy provided (e.g., cryoablation, ultrasound, etc.).

In the illustrative embodiment, catheter <NUM> includes a cable connector or interface <NUM>, a handle <NUM>, and a shaft <NUM> having a proximal end <NUM> and a distal <NUM> end. Catheter <NUM> may also include other conventional components not illustrated herein such as a temperature sensor, additional electrodes, and corresponding conductors or leads. Connector <NUM> provides mechanical and electrical connection(s) for cable <NUM> extending from generator <NUM>. Connector <NUM> may include conventional components known in the art and as shown is disposed at the proximal end of catheter <NUM>.

Handle <NUM> provides a location for the clinician to hold catheter <NUM> and may further provide means for steering or the guiding shaft <NUM> within body <NUM>. For example, handle <NUM> may include means to change the length of a guidewire extending through catheter <NUM> to distal end <NUM> of shaft <NUM> or means to steer shaft <NUM>. Moreover, in some embodiments, handle <NUM> may be configured to vary the shape, size, and/or orientation of a portion of the catheter, and it will be understood that the construction of handle <NUM> may vary. In an alternate embodiment, catheter <NUM> may be robotically driven or controlled. Accordingly, rather than a clinician manipulating a handle to advance/retract and/or steer or guide catheter <NUM> (and shaft <NUM> thereof in particular), a robot is used to manipulate catheter <NUM>. Shaft <NUM> is an elongated, tubular, flexible member configured for movement within body <NUM>. Shaft <NUM> is configured to support electrode assembly <NUM> as well as contain associated conductors, and possibly additional electronics used for signal processing or conditioning. Shaft <NUM> may also permit transport, delivery and/or removal of fluids (including irrigation fluids and bodily fluids), medicines, and/or surgical tools or instruments. Shaft <NUM> may be made from conventional materials such as polyurethane and defines one or more lumens configured to house and/or transport electrical conductors, fluids or surgical tools, as described herein. Shaft <NUM> may be introduced into a blood vessel or other structure within body <NUM> through a conventional introducer. Shaft <NUM> may then be advanced/retracted and/or steered or guided through body <NUM> to a desired location such as the site of tissue <NUM>, including through the use of guidewires or other means known in the art.

In some embodiments, catheter <NUM> is a grid catheter having catheter electrodes (not shown in <FIG>) distributed at the distal end of shaft <NUM>. In some embodiments, catheter <NUM> has sixteen catheter electrodes. In other embodiments, catheter <NUM> includes ten catheter electrodes, twenty catheter electrodes, or any other suitable number of electrodes for performing electroporation. In some embodiments, the catheter electrodes are ring electrodes, such as platinum ring electrodes. Alternatively, the catheter electrodes may be any other suitable type of electrodes, such as partial ring electrodes or electrodes printed on a flex material. In various embodiments, the catheter electrodes have lengths of <NUM>, <NUM>, <NUM>, and/or any other suitable length for electroporation.

Localization and navigation system <NUM> may be provided for visualization, mapping and navigation of internal body structures. Localization and navigation system <NUM> may include conventional apparatus known generally in the art. For example, localization and navigation system <NUM> may be substantially similar to the EnSite Precision™ System, commercially available from Abbott Laboratories, and as generally shown in commonly assigned <CIT> titled "Method and Apparatus for Catheter Navigation and Location and Mapping in the Heart". In another example, localization and navigation system <NUM> may be substantially similar to the EnSite X™ System, as generally shown in <CIT> titled "Method for Medical Device Localization Based on Magnetic and Impedance Sensors". It should be understood, however, that localization and navigation system <NUM> is an example only, and is not limiting in nature. Other technologies for locating/navigating a catheter in space (and for visualization) are known, including for example, the CARTO navigation and location system ofBiosense Webster, Inc. , the Rhythmia® system of Boston Scientific Scimed, Inc. , the KODEX® system of Koninklijke Philips N. , the AURORA® system of Northern Digital Inc. , commonly available fluoroscopy systems, or a magnetic location system such as the gMPS system from Mediguide Ltd. In this regard, some of the localization, navigation and/or visualization system would involve a sensor be provided for producing signals indicative of catheter location information, and may include, for example one or more electrodes in the case of an impedance-based localization system, or alternatively, one or more coils (i.e., wire windings) configured to detect one or more characteristics of a magnetic field, for example in the case of a magnetic-field based localization system As yet another example, system <NUM> may utilize a combination electric field-based and magnetic field-based system as generally shown with reference to <CIT> entitled "Hybrid Magnetic-Based and Impedance Based Position Sensing".

In at least some of the embodiments described herein, a catheter includes an array of electrodes that define one or more pixels. The array of electrodes may be arranged, for example, on a grid catheter (e.g., as shown in <FIG>) or on a basket catheter (e.g., as shown in Figures 6A-7C). Alternatively, the array of electrodes may be arranged on any suitable catheter assembly.

<FIG> is a side view of one embodiment of a grid assembly <NUM> that may be used with catheter <NUM> in system <NUM>. Those of skill in the art will appreciate that, in other embodiments, any suitable catheter may be used. In addition, those of skill in the art will appreciate that, although the embodiments disclosed herein are discussed in the context of a grid catheter, the methods and systems described herein may be implemented using any suitable catheter (e.g., basket catheters, etc.). As shown in <FIG>, grid assembly <NUM> is coupled to a distal section <NUM> of shaft <NUM>.

Grid assembly <NUM> includes a plurality of splines <NUM> extending from a proximal end <NUM> to a distal end <NUM>. Each spline <NUM> includes a plurality of electrodes <NUM>. In the embodiment shown in <FIG>, grid assembly <NUM> includes four splines <NUM>, and each spline <NUM> includes four electrodes <NUM>, such that electrodes <NUM> form a grid configuration. Accordingly, grid assembly <NUM> provides a four by four grid of electrodes <NUM>. In one embodiment, the spacing between each pair of adjacent electrodes <NUM> is approximately <NUM> millimeters (mm) such that the dimensions of the grid of electrodes <NUM> are approximately <NUM> x <NUM>. Alternatively, grid assembly <NUM> may include any suitable number of splines <NUM>, any suitable number of electrodes <NUM>, and/or any suitable arrangement of electrodes <NUM>. For example, in some embodiments, the spacing between each pair of adjacent electrodes is approximately <NUM> millimeters (mm). Further, in some embodiments, grid assembly <NUM> may include, for example, fifty-six electrodes arranged in a <NUM> x <NUM> grid.

Using grid assembly <NUM>, lesions may be generated at individual electrodes <NUM> using a monopolar approach (e.g., by applying a voltage between individual electrodes <NUM> and a return patch), or generated between pairs of electrodes <NUM> using a bipolar approach. Lesions may be generating within an anatomy by selectively energizing electrodes in a particular configuration and/or pattern (e.g., including energizing individual electrodes <NUM> independent of one another, or energizing multiple electrodes <NUM> simultaneously).

<FIG> is an image <NUM> showing grid assembly <NUM> positioned within a left atrium <NUM> of a patient's heart. As shown in <FIG>, grid assembly <NUM> covers a relatively wide area of the heart. The width of this area is generally larger than that needed to perform pulmonary vein isolation (PVI). Accordingly, to perform a successful PVI ablation, it may be possible to only energize a portion of grid assembly <NUM>.

Using bipolar delivery patterns, a plurality of different energization patterns are available using grid assembly <NUM>. For example, each electrode <NUM> may selectively function as a positive electrode, a negative electrode, or an inactive electrode. If all electrodes <NUM> are energized at the same polarity, then an indifferent electrode (e.g., one of surface electrodes <NUM>, <NUM>, and <NUM> (shown in <FIG>)) functions as a return electrode. If some electrodes <NUM> are energized at a positive polarity, and other electrodes <NUM> are energized at a negative polarity, no indifferent electrode is required, as there are current paths between electrodes <NUM>.

In the embodiments described herein, energy is delivered uniformly using quadripolar arrays (i.e., <NUM> x <NUM> arrays) of electrodes <NUM>. In this embodiment, grid assembly <NUM> includes four quadripolar arrays <NUM>, as shown in <FIG>. As will be appreciated by those of skill in the art, a plurality of different energization schemes are possible for a quadripolar array <NUM> of electrodes <NUM>. For example, in some embodiments, different quadripolar arrays <NUM> may share at least one electrode <NUM>.

For example, <FIG> illustrate a first energization pattern <NUM>, a second energization pattern <NUM>, and a third energization pattern <NUM>, respectively.

In first energization pattern <NUM>, a first electrode <NUM> is positive, a second electrode <NUM> is negative, a third electrode <NUM> is negative, and a fourth electrode <NUM> is positive. In second energization pattern <NUM>, first electrode <NUM> is positive, second electrode <NUM> is positive, third electrode <NUM> is negative, and fourth electrode <NUM> is negative. In third energization pattern <NUM>, first electrode <NUM> is positive, second electrode <NUM> is negative, third electrode <NUM> is positive, and fourth electrode <NUM> is negative.

Those of skill in the art will appreciate that other energization patterns are possible. Notably, other energization patterns are redundant to those shown in <FIG> (i.e., with the polarity of each electrode <NUM> switched), degenerate (i.e., with all electrodes <NUM> having the same polarity), or unequal (i.e., having a different number of positive and negative electrodes <NUM>).

<FIG> is an example energization pattern <NUM> for all sixteen electrodes <NUM> of catheter assembly <NUM>. Specifically, energization pattern <NUM> corresponds to each quadripolar array <NUM> using first energization pattern <NUM> (shown in <FIG>).

<FIG> is a diagram <NUM> simulating an electric field strength (e.g., in Volts/centimeter (V/cm)) when energization pattern <NUM> is implemented. As shown in diagram <NUM>, the electric field strength is highest around each electrode <NUM>. In contrast, the electric field strength is low at low field spots <NUM>. Low field spots <NUM> are generally located at a midpoint between adjacent electrodes <NUM> having the same polarity. Accordingly, with energization pattern <NUM>, low field spots <NUM> occur at approximately the center of each quadripolar array <NUM>. The low electric field strength occurs because the gradient of the electric field is at or near zero at low field spots <NUM>.

<FIG> is a diagram <NUM> simulating the potential field when energization pattern <NUM> is implemented. As shown in <FIG>, saddle points <NUM> correspond to the location of low field spots <NUM> in diagram <NUM>. At saddle points <NUM>, there is no slope, and thus no gradient (i.e., corresponding to zero electric field strength).

Notably, different energization patterns generally result in different low field spots. For example, <FIG> is a diagram <NUM> simulating an electric field strength for an energization pattern that corresponds to using second energization pattern <NUM> (shown in <FIG>) for each quadripolar array <NUM>. Again, the electric field strength is highest around each electrode <NUM>. However, in diagram <NUM>, low field spots <NUM> occur between electrodes <NUM> that are located in the same row. Accordingly, low field spots <NUM> are located at different positions than low field spots <NUM> (shown in <FIG>). Further, in diagram <NUM>, at the locations corresponding to low field spots <NUM> from diagram <NUM>, the electric field strength is relatively high.

As another example, <FIG> is a diagram <NUM> simulating an electric field strength for an energization pattern that corresponds to using third energization pattern <NUM> (shown in <FIG>) for each quadripolar array <NUM>. In diagram <NUM>, low field spots <NUM> occur between electrodes <NUM> that are located in the same column. Again, low field spots <NUM> are located at different positions that low field spots <NUM> (shown in <FIG>) and low field spots <NUM> (shown in <FIG>). Further, in diagram <NUM>, at the locations corresponding to low field spots <NUM> from diagram <NUM> and the locations corresponding to low field spots <NUM> from diagram <NUM>, the electric field strength is relatively high.

Accordingly, by applying combinations of energization patterns, a relatively uniform electric field strength can be achieved (as the low field spots in a particular energization pattern will be compensated for in other energization patterns). Thus, by cycling through multiple energization patterns, the overall ablation area generated will be relatively uniform.

For example, <FIG> is a representation <NUM> of diagram <NUM> (shown in <FIG>), <FIG> is a representation <NUM> of diagram <NUM> (shown in <FIG>), and <FIG> is a representation <NUM> of diagram <NUM> (shown in <FIG>). <FIG> is a diagram <NUM> showing representations <NUM>, <NUM>, and <NUM> superimposed on one another. As demonstrated by diagram <NUM>, when representations <NUM>, <NUM>, and <NUM> are superimposed on one another (corresponds to cycling through all three energization patterns), the ablation area generated is relatively uniform, with holes in one energization pattern being filled by other energization patterns.

Those of skill in the art will appreciate that other energization patterns (i.e., other than those shown in <FIG>) may be used for each quadripolar array <NUM>. For example, <FIG> illustrate a fourth energization pattern <NUM>, a fifth energization pattern <NUM>, a sixth energization pattern <NUM>, and a seventh energization pattern <NUM>. These energization patterns <NUM>, <NUM>, <NUM>, and <NUM> are unbalanced (i.e., with an unequal number of positive and negative electrodes).

In fourth energization pattern <NUM>, a first electrode <NUM> is negative, a second electrode <NUM> is negative, a third electrode <NUM> is negative, and a fourth electrode <NUM> is positive. In fifth energization pattern <NUM>, first electrode <NUM> is negative, second electrode <NUM> is negative, third electrode <NUM> is positive, and fourth electrode <NUM> is negative. In sixth energization pattern <NUM>, first electrode <NUM> is negative, second electrode <NUM> is positive, third electrode <NUM> is negative, and fourth electrode <NUM> is negative. In seventh energization pattern <NUM>, first electrode <NUM> is negative, second electrode <NUM> is positive, third electrode <NUM> is positive, and fourth electrode <NUM> is positive.

Although the embodiments described herein are discussed in the context of IRE/PFA, those of skill in the art will appreciate that the methods and systems described herein may also be utilized for RF ablation applications.

Further, those of skill in the art will appreciate that the techniques described herein may be implemented with catheter configurations other than grid assembly <NUM>. For example, <FIG> are perspective views of one embodiment of a basket assembly <NUM> including a plurality of splines <NUM> that form a basket, each spline including a plurality of electrodes <NUM>. Similar to grid assembly <NUM>, quadripolar arrays can be defined by sets of electrodes <NUM>. For example, a first electrode <NUM>, second electrode <NUM>, third electrode <NUM>, and fourth electrode <NUM> define a quadripolar array <NUM> (shown in <FIG>). Other catheter configurations may also utilize similar implementations.

<FIG> are views of another embodiment of a basket assembly <NUM> that may be used with the electrode energization techniques described herein. Specifically, <FIG> is a perspective view of basket assembly <NUM>, and <FIG> are side views of basket assembly <NUM> positioned within a pulmonary vein <NUM>.

Basket assembly <NUM> includes a plurality of splines <NUM> that form a basket. In this embodiment, each spline <NUM> has a generally sigmoidal shape. The sigmoidal shape of splines <NUM> results in adjacent splines <NUM> maintaining roughly the same distance between one another along the length of splines <NUM>, which may improve lesion quality. In this embodiment, basket assembly <NUM> includes eight splines <NUM>. Alternatively, basket assembly <NUM> may include any suitable number of splines <NUM>.

As shown in <FIG>, basket assembly <NUM> may include a selectively inflatable balloon <NUM> positioned in an interior of the basket. Balloon <NUM> may facilitate supporting splines <NUM> (e.g., when splines are pressed against tissue). In some embodiments, balloon <NUM> is omitted. Additional detail regarding basket assemblies with sigmoidal-shaped splines may be found in International Application No. <CIT>, and U. Provisional Patent Application No. <CIT>.

Each spline <NUM> include at least one electrode <NUM> that is selectively energizable using the systems and methods disclosed herein. For example, Figure 7B shows one elongated electrode <NUM> on each spline <NUM>, whereas Figure 7C shows a plurality of individual electrodes <NUM> on each spline <NUM>. Electrodes <NUM> are generally located on a distal portion of basket assembly <NUM>, to facilitate contacting tissue of pulmonary vein <NUM>. Alternatively, any suitable configuration of electrodes <NUM> may be used. Similar to the embodiments described previously, sets of individual electrodes <NUM> on basket assembly <NUM> may define quadripolar arrays, and energization schemes similar to those described above may be suitably implemented.

As described herein, electrodes on a catheter are selectively energized to generate different patterns. <FIG> is a schematic diagram of one embodiment of a switching architecture <NUM> that may be used to selectively energize electrodes on a catheter <NUM>. Specifically, switching architecture includes a catheter <NUM>, a pulse source <NUM>, and a switching unit <NUM> coupled between catheter <NUM> and pulse source <NUM>.

Pulse source <NUM> generates energy pulses to be applied by the electrodes (not shown) on catheter <NUM>. Further, switching unit <NUM> includes a plurality of switching circuits <NUM> for selectively delivering energy pulses from pulse source <NUM> to the electrodes. In this embodiment, switching unit <NUM> includes a switching circuit <NUM> (and corresponding channel) for each electrode. Each switching circuit <NUM> receives an energy pulse from pulse source <NUM> and, depending on a configuration of switches within switching circuit <NUM>, delivers a positive pulse, a negative pulse, or no pulse to the corresponding electrode. Accordingly, by controlling switching circuits <NUM>, the electrodes on catheter <NUM> are selectively energizable.

The embodiments described herein are directed to an apparatus for controlling an electroporation catheter. The electroporation catheter includes a distal end, a proximal end, a plurality of splines extending from the distal end to the proximal end, and a plurality of electrodes arranged on the plurality of splines and defining at least one quadripolar array, each quadripolar array defined by four electrodes of the plurality of electrodes. The apparatus includes a pulse generator coupled to the electroporation catheter, and a computing device coupled to the pulse generator, the computing device operable to control the pulse generator to selectively energize the electrodes defining the at least one quadripolar array according to a first energization pattern, and selectively energize the electrodes defining the at least one quadripolar array according to a second energization pattern, wherein the first and second energization patterns are different from one another.

Although certain embodiments of this disclosure have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments. All directional references (e.g., upper, lower, upward, downward, left, right. leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of the disclosure. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made within the scope of the invention as defined in the appended claims.

Claim 1:
An apparatus for controlling an electroporation catheter (<NUM>), the electroporation catheter including a distal end (<NUM>), a proximal end (<NUM>), a plurality of splines (<NUM>, <NUM>, <NUM>) extending from the distal end to the proximal end, and a plurality of electrodes (<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>, <NUM>) arranged on the plurality of splines and defining at least one quadripolar array (<NUM>, <NUM>), each quadripolar array defined by four electrodes of the plurality of electrodes, the apparatus comprising:
a pulse generator (<NUM>) coupled to the electroporation catheter; and
a computing device (<NUM>) coupled to the pulse generator, the computing device operable to control the pulse generator to:
selectively energize the electrodes defining the at least one quadripolar array according to a first energization pattern (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>); and
selectively energize the electrodes defining the at least one quadripolar array according to a second energization pattern (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), wherein the first and second energization patterns are different from one another;
wherein energizing the electrodes according to the first energization pattern generates first low field spots (<NUM>, <NUM>, <NUM>, <NUM>), wherein energizing the electrodes according to the second energization pattern generates second low field spots (<NUM>, <NUM>, <NUM>, <NUM>), and wherein the first and second low field spots are located in different locations.