Electrodes and methods of applying electric field to the electrodes

Abstract

Apparatuses and methods for treating tissue with electric pulses that may adjust and control energy (e.g., sub-microsecond pulses) to electrodes or electrode pairs, or subsets of the electrode pairs on an applicator based on the configuration of the applicator. These methods and apparatuses may also be configured to reduce arcing based on the shape (and in some cases, the separation of the electrodes) and / or may adjust the applied electrical energy based on the type of tissue sensed.

Description

ELECTRODES AND METHODS OF APPLYING ELECTRIC FIELD TO THE ELECTRODESCLAIM OF PRIORITY

[0001] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 616,497, titled “ELECTRODES AND METHODS OF APPLYING ELECTRIC FIELD TO THE ELECTRODES,” filed on December 29, 2023, which is herein incorporated by reference in its entirety.BACKGROUND

[0002] Electrosurgical procedures may apply electrical energy between the arms of a surgical tool in order to treat tissue. For example, electrosurgical treatments may be used to ablate tissue, and in particular may be useful to treat cardiac tissue. For example, an electrosurgical device having arms that apply electrical energy may be used to treat a cardiac disorder such as atrial fibrillation or other heart arrhythmia. Ablation of cardiac tissue may be useful to create scar tissue that may interrupt the path of errant electrical impulses in the heart tissue. Although ablation has been proposed using a variety of thermal techniques, such as freezing via cryogenic probe, heating via radio frequency (RF) energy, surgical cutting, and other techniques, it may be particularly helpful to use very short, relatively high energy pulses, such as microsecond or sub-microsecond pulses to ablate the tissue.

[0003] However, it may be difficult to control ablation when using microsecond and submicrosecond, high fi eld- strength pulses. In particular, it may be difficult to prevent arcing and / or achieve consistent ablation when using devices having electrodes configured to be positioned on opposite sides of the tissue, such as (but not limited to) electrodes in opposing arms, including scissoring arms and / or arms where the electrodes are not parallel, as the variable distance between the arms when clamping onto different tissues or different regions of the tissue may make it difficult to achieve a relatively consistent ablation when applying an electric field between electrodes, such as pairs of electrodes. Further, the energy requirements for generating an electrical field between electrodes of an applicator, including applicators having electrodes on the arms (particularly longer arms) may increase the likelihood of undesirable arcing and make the procedure more difficult and demand greater equipment resources.

[0004] Thus, it would be helpful to provide methods and apparatuses for treating a tissue using apparatuses having a plurality of electrodes that address various deficiencies of the existing apparatuses and methods.SUMMARY OF THE DISCLOSURE

[0005] The present disclosure includes various improvements which may enhance the construction, operation, and methods of use of surgical devices for ablating tissue, such as cardiac tissue. The methods and apparatuses described herein may include applicators including a plurality of electrodes for delivering energy to tissue in which the relative positions of the electrodes may change relative to each other when operating the apparatus. The methods and apparatuses described herein may improve the control of the application of energy to different regions of the applicator, including in particular to different electrodes of the applicator, for example, based in part on the sensed configuration of the applicator, such as, the separation between electrodes on the applicator. In variations in which the applicator includes one or more movable arms, the apparatus or method may control the applied energy based on the separation between the arms (including the angle between two arms). In general, the apparatuses and method described herein may include one or more arms that are configured to contact, and at least partially enclose a target tissue to be treated. The one or more arms may equivalently be referred to herein as arms. In examples having two arms (e.g., two arms), the angle between the two arms (or arms) may be referred to herein as the arm angle or arm angle, particularly in reference to scissoring arms (e.g., scissoring arms). In variations in which the applicator includes one or more arms (e.g., arms) that may change length and / or diameter of a loop surrounding or partially surrounding the target tissue, the apparatus or method may control the applied energy based on the length of the arm and / or loop (and in some cases the derived diameter). In any of these methods and apparatuses the configuration of the applicator may be used to determine or derive a distance(s) between the electrodes applying the energy to the target tissue and / or a thickness of the tissue held by the applicator and may be used to control the applied energy.

[0006] In some examples the methods and apparatuses described herein may include an applicator having arms (e.g., a pair of arms) that are configured to diverge from each other. For example, the applicator may include a pair of arms holding electrodes that may be opened or closed during operation of the applicator, e.g., to hold (clamp, grasp, etc.) tissue between the arms. The arms may be configured to scissor open and closed, to open and close in parallel, or to open and / close in some combination of scissoring and parallel opening. In some examples the applicator may include an arm in a form of a flexible jaw (which may also be referred to as a single arm or single jaw) that may curve, curl, loop or wrap over the target tissue, so that electrodes on the flexible arm may be positioned on opposite sides of the target tissue.

[0007] The methods and apparatuses described herein may be configured to determine a relative orientation of the applicator, such as the relative positions of the jaw(s) / arm(s) and / or the relative positions of the electrodes on the jaw(s) / arm(s), and may use this relative position information to control the applied energy. In particular, these methods and apparatuses may be configured to apply a consistent electric field based on the relative position information. In some examples, these methods and apparatuses may be configured to control the applied energy density between electrodes on the applicator based on the separation between the electrodes (e.g., electrode pairs) applying the energy. These methods and apparatuses may control one or more of the pulse width of the applied energy, the amplitude (e.g., voltage and / or current amplitude), the number of pulses applied, etc.

[0008] In any of these methods and apparatuses the applied energy may be configured to be adjusted dynamically, as the configuration of the applicator changes. For example, in variations including one or more moving arms, the energy applied between electrodes on the applicator may be adjusted as a function of the separation between the arms; in examples having scissoring arms, the applied energy may be adjusted based on the angle between the arms. In variations having a looped or curve applicator (e.g., having a looped or curved arm) the applied energy may be adjusted based on the radius (or diameter) of the curved or looped region.

[0009] The applied energy may be controlled to achieve a more uniform ablation region, including a more uniform thickness and / or width of the ablated region in the tissue, a more uniform ablation profile along the length and / or thickness, etc. Alternatively or additionally, the applied energy may be controlled to maintain a relatively consistent (e.g., approximately constant) energy density, particularly (but not exclusively) in the thicker tissue, e.g., by increasing the pulse width as the spacing between the electrodes diverges, such as in examples having one or more moving arms (for example, as the arms open / close). In some examples the methods and apparatuses may be configured to maintain a relatively consistent energy density, for example, by changing the number of pulses as the separation between electrodes changes.

[0010] Alternatively or in addition to controlling the applied energy based on the configuration of the applicator (e.g., spacing between active electrode pairs, etc.) the methods and apparatuses may control the applied energy based on a sensed property from the tissue being treated. In particular these methods and apparatuses may control the applied energy based on a sensed electrical property, including but not limited to electrical impedance. The sensed property may be sensed between electrodes on the applicator, including between one or more pairs of electrodes used to apply electrical energy. In some cases the sensed propertymay confirm contact between some or all of the electrodes and the tissue. For example, since each electrode pair of an applicator may be controlled independently, the methods and apparatuses described herein may measure the impedance in each electrode pair and may determine if tissue is in contact with only a part of the applicator (e.g., a subset of the electrodes), so energy may be delivered only where tissue is in contact with electrodes, and not delivered to the electrodes that are not contacting tissue. Alternatively or additionally, in some cases the sensed property may indicate the type of tissue in contact with the electrodes (e.g., fat / non-fat, muscle, skin, tumor, etc.). For example, by measuring impedance between electrodes (e.g., each electrode pair), the methods or apparatuses described herein may determine if part of the arm is in contact with non-fat (e.g., “normal”) tissue and another part of the arm is in contact with fat between the electrodes and / or between the electrodes and the target (non-fat) tissue; the electrode in contact with the fat may be pulsed with a higher field strength and / or energy (e.g., higher voltage, etc.) to treat the target tissue beyond the fat.

[0011] In addition to controlling the applied energy to control the ablation, any of these methods and apparatuses may be configured to control the applied energy to prevent arcing. For example, the maximum energy applied may be limited based on a separation between the electrodes applying energy, as may be determined from the configuration of the applicator. In examples having scissoring arms (e.g., arms), the energy may be limited based on the separation between the arms (e.g., arms). Thus energy applied to the electrodes nearer to the vertex (pivot point) of the arms (e.g., arms) may be limited to prevent arcing. In some examples the applied energy (e.g., field strength, voltage, etc.) near the vertex (sometimes also referred to as fulcrum) region may be reduced to reduce or prevent arcing, while still maintaining a higher voltage further away from the fulcrum where the chances of arcing are reduced.

[0012] Thus, the methods and apparatuses described herein may provide a predictable, and in some cases even, or approximately evenly distributed, treatment of tissues having different thicknesses and / or compositions. This may be achieved in any of the methods and apparatuses described herein by using a plurality of electrodes arranged along at least a portion of a length (and / or in some cases, a breadth) of an applicator between which tissue may be positioned. As mentioned, these methods and apparatuses may adjust the energy applied between subsets of the plurality of electrodes based on the configuration of the applicator (from which a thickness of the tissue and / or spacing of the electrodes may be derived) in order to provide a desired ablation within the tissue.

[0013] The apparatuses described herein for treating a tissue between pairs of electrodes of an applicator may include a pair of arms (e.g., arms) holding and / or incorporatingelectrodes. For example, these methods may be configured to treat tissue by applying electrical pulses, and in some cases microsecond or sub-microsecond pulses (e.g., nanosecond pulses) or energy. The methods and apparatuses described herein may control the application of energy to a plurality of electrodes arranged along a portion or a full proximal- to-distal length of the arms so as to maintain a consistent electrical field, e.g., a target electrical field, within the tissue to be treated (even as the tissue thickness between the electrodes changes) and / or to achieve a consistent ablation of target tissue, while reducing the risk of arcing and minimizing the energy required to achieve relatively high-field treatment.

[0014] Thus, in some examples these methods and apparatuses described herein may be configured to generate a region of consistent (e.g., in some cases, near-constant) electric field strength between the electrodes on either sides of a region of tissue, based on the separation between the electrodes. For example, described herein are electrode apparatuses having scissoring arms (e.g., arms) that pivot about a fulcrum for delivering high field- strength electric pulses that are configured to generate a region of consistent electric field strength between the arms based on the angle between the arms. For example, an apparatus may include: a first arm having a proximal end and a distal end; a second arm having a proximal end and a distal end; a plurality of electrodes positioned along at least a portion of a length of the first arm; an arm actuator configured to adjust an angle between the first arm and the second arm; an arm angle sensor configured to sense the angle between the first arm and the second arm; and a controller receiving input from the arm angle sensor and configured to adjust the energy applied to the plurality of electrodes positioned along the length of the first and / or second arm based on the angle between the first arm and the second arm. Applying more energy to the electrodes that are further from the fulcrum, and / or applying more energy to the electrodes that are in regions that further apart from each other (when tissue is present between the electrodes) may result in a more even treatment throughout the tissue, even when the thickness of the tissue between the electrodes varies.

[0015] Although the methods and apparatuses described herein may be particularly well suited for sub-microsecond pulsing (e.g., nanosecond pulsing) treatments, the methods and apparatuses described herein may be used with, or adapted for use with, any pulsed electrical energy, including but not limited to millisecond pulsing, microsecond pulsing, monophasic or biphasic pulsing, or other appropriate energy modalities that would benefit from a consistent electric field or constant energy delivery. The method and apparatuses described herein may be used with bipolar energy delivery (e.g., applied between pairs of electrodes). These methods and apparatuses may also be adapted for use with monopolar energy delivery. For example, different electrodes of an applicator may be configured as monopolar electrodes;the energy applied to each monopolar electrode may be adjusted based on the tissue type and / or the amount of contact with the tissue; if an electrode is in contact with fat, more energy may be applied to the electrode as compared with electrodes in contact with other types of tissue. Alternatively, in some examples, monopolar electrodes that are not in contact with tissue may not be used to apply energy.

[0016] In any of the apparatuses of the present disclosure the energy controller may be configured to adjust the energy applied to the plurality of electrodes positioned along the length of the first arm based on the angle between the first arm and the second arm so that the applied energy results in a consistent (e.g., constant, approximately constant or near-constant) field strength and / or ablation dimensions between the first arm and the second arm along a distal to proximal line extending between the first and second arms. The consistent field strength may be an approximately constant or near-constant field strength, for example, a field strength that varies + / - 50% or less (e.g., 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, etc. or less). In some examples the field strength between the first arm and the second arm along the distal to proximal line may be at a consistent angle intermediate between the arms. In any of these examples the energy applied may be controlled by controlling one or more of the current, voltage, pulse width (pulse duration), pulse number, frequency, and / or power, in order to provide an electric field between the arms to treat the tissue held between the arm, including in some examples to ablate the tissue. In some examples the applied field strength may vary, but the methods and apparatuses described herein may limit or prevent arcing by reducing the field strength significantly for electrodes that are separated by less than a predetermined threshold (e.g., near the fulcrum region when using scissoring arms).

[0017] Additionally or alternatively, any of the apparatuses described herein may be configured to select a region (or regions) of the lengths of the first and second arm in which to apply energy from the plurality of electrodes, for example, based on regions having electrodes that are in contact with tissue. Any of these apparatuses may detect (by one or more sensors and / or by using the electrodes themselves) contact with tissue between the arms. According to some implementations, only the subset of electrodes that are in contact with the tissue may be used to apply high energy pulses, e.g., microsecond or submicrosecond (e.g., nanosecond) pulses. In any of these examples, the controller (e.g., energy controller) may be configured to detect a subset of the plurality of electrodes that are in contact with a tissue and to limit the applied energy to the subset. In some examples the apparatus may determine a type of tissue (e.g., fat / non-fat) based on a sensed electrical property, such as impedance, capacitance, etc. The energy controller may, therefore, beconfigured to detect a subset of the plurality of electrodes that are in contact with the tissue or one or more types of tissue, for example, based on impedance values for the electrodes of the first plurality of electrodes. Alternatively or additionally, in some examples the energy controller may determine which regions (e.g., which subset of electrodes) are in contact with the tissue based on one or more of pressure sensor, contact sensor, optical sensor, etc.

[0018] As mentioned, any of these apparatuses may include a first plurality of electrodes positioned along at least a portion of the length of the first arm and a second plurality of electrodes positioned along at least a portion of the length of the second arm. The apparatus may be configured to apply energy between pairs of electrodes on opposite arms (e.g., a first electrode on the first arm and a second, opposite electrode on the second arm). For example, the controller may be configured to adjust the energy applied between pairs of electrodes from the plurality of electrodes positioned along the length of the first arm and the second plurality of electrodes positioned along the length of the second arm that are opposite each other, based, for example, on the angle between the first arm and the second arm.

[0019] In general, the methods and apparatuses described herein may modulate the applied energy to individual electrode pairs based on the separation between electrodes forming the electrode pairs. In some examples, the relative thickness of the tissue between the arms (and therefore the separation between the electrodes positioned on arms) may vary along the length of the arms. The methods and apparatuses described herein may adjust the applied energy, including in some cases the voltage applied between the electrodes to maintain a consistent electric field (as described above) and / or consistent ablation (depth or width). As mentioned, any of the electrical parameters of the pulsed energy may be varied to achieve this. For example, these methods and apparatuses may maintain a constant voltage, so as the arms change separation between the electrodes, the pulse width and / or number of pulses may be varied as the separation between the arms (and therefore electrodes) changes, to provide a relatively constant energy delivery. In variations in which the electrodes are positioned on just one of the arms the energy controller may be configured to control the energy applied to adjacent pairs of electrodes (on the same side arm) to produce a line or plane of consistent (e.g., relatively constant) electrical field strength that is between the first arm and the second arm. In some examples the line or plane of consistent field strength may be at consistent angle, and this angle may be referred to as the consistent field angle and may be approximately halfway between the first arm and the second arm, regardless of how open / closed the arms are (e.g., regardless of the arm angle between the first and second arms). The consistent field angle may be measured relative to the first arm. For example, the consistent field angle may apply a consistent field strength through a midline of the tissueheld between the arms. Alternatively, the line or plane of consistent angle may curve; for example, the field strength may be adjusted to follow the morphology of the tissue. In some examples the line or plane of consistent field strength may be parallel to the first arm (or in some cases, parallel to the second arm).

[0020] Similarly, in variations in which electrodes are distributed on both the first arm and the second arm, the controller may be configured to control the energy applied to opposing pairs of electrodes (on the opposite sides of the first and second arms) to produce a line or plane of consistent (e.g., relatively constant) electrical field strength that extends between the first arm and the second arm. As mentioned above, in some examples the line or plane of consistent field may be at a consistent angle; in some examples the line or plane may be curved. In some examples, the line or plane may be parallel to one of the arms.

[0021] According to some embodiments of the present disclosure, the arms may be configured to pivot relative to each other. For example, the first arm may be configured to pivot relative to the second arm, the second arm may be configured to pivot relative to the first arm, and / or the first and second arms may be configured to pivot relative to each other. The relative movement of the arms may be referred to herein as scissoring, as the first and second arms may open and close in a scissoring manner, resulting in increasing or decreasing the arm angle, e.g., the angle between the first arm and the second arm.

[0022] In any of these examples the first arm and / or the second arm may be moved relative to each other by operating the arm actuator. The arm actuator may include a handle and / or grip. The arm actuator may be configured to be held by one or more of the fingers (index finger, thumb, ring finger, etc.), palm, etc. In some examples the arm actuator may include a button, slider, lever, etc. The arm actuator may be powered (e.g., may include a motor, etc.) or unpowered. The arm actuator may be biased, e.g., including one or more springs, etc. In some examples the arm actuator may include a lock, holding the relative position of the first and second arms. In some examples, the actuator may comprise a plunger and / or a latch for actuating / controlling the clamping. In any of the apparatuses described herein, the arms may be controlled by a controller or processor that may control the opening and / or closing of the arm, including controlling the angle between the arms. For example, the arms may be motorized and / or computer-controlled so that they may be automatically or semi -automatically opened and / or closed. In any of these apparatuses the arms may be controlled as part of a robotic manipulator, and they may be attached to a robotic arm.

[0023] The pulse generator may be coupled to the controller (e.g., energy controller). In any of these examples the pulse generator may comprise a microsecond or sub-microsecond, high voltage pulse generator (e.g., a nanosecond pulse generator). The energy controller maybe a part of (e.g., integrated with) the pulse generator or it may be separate from the pulse generator, and coupled thereto. In general, the apparatuses described herein may include a single controller (e.g., which may include the energy controller) or multiple sub-controllers (e.g., energy controller, mapping controller, sensing controller, etc.). It should be understood that, when used herein, the term “controller” or “energy controller” shall include one or a plurality of controllers configured to perform various operations described herein. The controller(s), including the energy controller, may include one or more outputs, including one or more outputs to a display and / or memory, etc. The apparatus may include one or more inputs, including a control (e.g., trigger, button, dial, touchscreen, etc.) for activating the application of energy, etc. As mentioned, these apparatuses may include one or more sensors, including but not limited to the arm angle sensor, contact sensor(s), etc. In some examples, all or some of the electrodes (of the plurality of electrodes) may act or operate as sensors. For example, the apparatus may be configured to detect contact between the electrode(s) and the tissue based on a sensed electrical property (e.g., resistance, capacitance, inductance, etc.).

[0024] The first and second arm may be relatively long (e.g., 1 cm or greater, 1.2 cm or greater, 1.5 cm or greater, 1.8 cm or greater, 2 cm or greater, 2.2 cm or greater, 2.5 cm or greater, 2.7 cm or greater, 3 cm or greater, 3.5 cm or greater, 4 cm or greater, 5 cm or greater, 6 cm or greater, 7 cm or greater, 8 cm or greater, 9 cm or greater, 10 cm or greater, 12 cm or greater, 15 cm or greater, 20 cm or greater, etc.). The first arm and second arm may be curved and / or bent. In some examples the first and second arms are straight. In some examples, the first and second arm may be parallel or nearly-parallel to each other rather than positioned at an angle to each other. In some examples, the apparatus may be configured to detect spacing between the first and second arm. For example, the apparatus may incorporate various types of distance / gap / position sensors, including linear potentiometer.

[0025] The apparatuses described herein may include any appropriate number of electrodes of the plurality of electrodes (e.g., the first and / or second plurality of electrodes). For example, the plurality of electrodes positioned along at least a portion of a length of the first arm between the proximal end and the distal end may include 2 or more electrodes, 3 or more electrodes, 4 or more electrodes, 5 or more electrodes, 6 or more electrodes, 7 or more electrodes, 8 or more electrodes, 9 or more electrodes, 10 or more electrodes, 11 or more electrodes, 12 or more electrodes, 13 or more electrodes, 14 or more electrodes, 15 or more electrodes, 16 or more electrodes, etc. The electrodes of the plurality of electrodes may be flat or curved (e.g., surface electrodes), may be ring electrodes, may be recessed electrodes, may be protruding electrodes (e.g., may be proud of the outer surface of the first or second arms), and may generally be formed of a conductive material.

[0026] The electrodes of the plurality of electrodes may be any appropriate size, including any appropriate length, width and / or surface area, such as, e.g., a length of between about 0.1 mm to 25 mm long or longer (e.g., between about 0.2 mm to 25 mm, between about 0.5 mm to about 15 mm, between about 1 mm to about 15 mm, between about 1mm to about 5 mm, between about 1 mm to about 3 mm, etc.).

[0027] The arms may be any appropriate length, e.g., between about 1 cm and about 20 cm, between about 2 mm and about 5 cm, between about 2 mm and about 2 cm, between about 2 mm and about 1 cm, between about 2 mm and about 8 mm, between about 2 cm and about 14 cm, between about 2 cm and about 13 cm, between about 2 cm and about 12 cm, between about 2 cm and about 11 cm, between about 2 cm and about 10 cm, etc.). The width may be about 0.5 mm to 3 cm wide (e.g., about 0.5 mm to 30 mm, 0.5 mm to 25 mm, about 0.5 mm to 20 mm, 0.5 mm to 15 mm, 0.5 mm to 12 mm, 0.5 mm to 11 mm, 0.5 mm to 10 mm, 0.5 mm to 9 mm, 0.5 mm to 9 mm, etc.). Any appropriate length and width of the arms may be used. The electrodes may be arranged along the length of the arm or arms. In some examples an array of electrodes (e.g., ri m electrodes) may be arranged along the length of the electrodes (e.g., n may be between 1 and 10, and m may be between 2 and 30 or more, e.g., between 2 and 25, between 2 and 20, between 2 and 15, between 2 and 13, between 2 and 12, between 2 and 11, between 2 and 10, between 2 and 9, between 2 and 8, between 2 and 7, between 2 and 6, etc. where m extends down the length of the arms. Each electrode may have any appropriate surface area for applying energy as described herein. For example, each electrode may have a surface area of between about 0.1 mm2and about 100 mm2, e.g., between about 0.2 mm2and about 75 mm2, between about 0.3 mm2and about 60 mm2, between about 0.5 mm2and about 50 mm2, between about 0.5 mm2and about 40 mm2etc.). The electrodes of the plurality of electrodes may be arranged along the first and / or second arms on a surface that faces the opposite arm, so that tissue held between the arms is held against the electrodes.

[0028] As mentioned, any of these apparatuses may include a position sensor, for example, an arm angle sensor. The arm angle sensor may generally detect or determine the angle between the first arm and the second arm. The angle may be changed by the operation of the arm actuator, and the arm angle sensor may determine the arm angle. Any appropriate sensor capable of providing the arm angle or of providing information that may be used to determine the arm angle may be used. For example, the position sensor may be one or more of: a magnetic angle sensor, a capacitive sensor, a photoelectric sensor, an eddy current sensor, and / or a position encoder. In some cases the sensor may be a sensor detecting the relative position of the actuator (e.g., trigger, control, etc.) for moving the applicator bodyand / or arms. For example, the position sensor may be a linear sensor configured to determine the relative position of the arms (in examples including arms) based on the relative movement of the shaft and handle driving opening / closing of the arms.

[0029] According to one aspect of the present disclosure, an applicator apparatus for delivering pulsed electrical energy may comprise: a first arm having a proximal end and a distal end; a second arm having a proximal end and a distal end; a plurality of electrodes positioned along at least a portion of a length of the first arm; an arm actuator configured to adjust a separation between the first arm and the second arm; a position sensor configured to sense a relative position between the first arm and the second arm; and a controller receiving input from the position sensor and configured to adjust the energy applied to the plurality of electrodes based on the relative position between the first arm and the second arm. In some examples, the controller is configured to adjust the applied energy to provide a consistent field strength between the first arm and the second arm at least along a portion of a distal to proximal line between the first and second arms. In some examples, the controller is configured to adjust the applied energy to provide a consistent region of ablation within a tissue between the first arm and the second arm.

[0030] In any of these examples the applicator apparatus or electrode apparatus for delivering pulsed electric energy may include: a first arm having a proximal end and a distal end; a second arm having a proximal end and a distal end; a first plurality of electrodes positioned along at least a portion of a length of the first arm between the proximal end and the distal end; a second plurality of electrodes positioned along at least a portion of a length of the second arm between the proximal end and the second end; an arm actuator configured to adjust a relative position between the first arm and the second arm; a position sensor configured to sense the angle between the first arm and the second arm; and an energy controller receiving input from the position sensor and configured to adjust energy applied between individual pairs of electrodes from the first plurality of electrodes and the second plurality of electrodes, based on the angle between the first arm and the second arm. In any of these methods and apparatuses, the energy applied may be controlled and / or adjusted so that the field strength is delivered in a predictable manner. In some cases the field strength may be delivered so that the applied energy results in a consistent field strength between the first arm and the second arm along at least a portion of a distal to proximal line or plane extending between the first and second arms. In some examples it may be desirable to apply different fields strength to different regions of the treatment area. For example, the apparatus may sense the impedance along different regions or parts of the same region and adjusts the applied energy accordingly. For example, regions of the tissue between the arms may havedifferent impedances where the fat content of the tissue is higher or lower, therefore, the fields strength may be adjusted accordingly.

[0031] Also described herein are methods, including (but not limited to) methods for treating a tissue using the apparatuses of the present disclosure. For example, described herein are methods comprising: determining a relative position between a first arm and a second arm of an applicator, wherein the first and the second arms are clamped on a tissue of a subject; and applying energy between pairs of electrodes positioned on the first arm and / or the second arm, wherein the applied energy is adjusted for each pair of electrodes based on the relative position between the first arm and the second arm. In some examples, the method may comprise: determining an angle between a first arm and a second arm of an applicator, wherein the first and the second arms are clamped on a tissue of a subject; and applying energy between pairs of electrodes positioned on the first arm and / or the second arm, wherein the applied energy is adjusted for each pair of electrodes based on the angle between the first arm and the second arm.

[0032] In any of these methods the energy may be adjusted so that the applied energy results in a consistent field strength between the first arm and the second arm along a distal to proximal line extending between the first and second arms as described above. In general, the methods and apparatuses may adjust and control the application of energy between individual pairs or sets of electrodes. The applied energy may be adjusted applying different field strength to different regions, if applicable.

[0033] In some examples the energy may be adjusted so that the electrode pairs closer to a vertex (e.g., a vertex region) between the first arm and the second arm have a lower applied voltage and / or lower applied pulse number than electrode pairs further from the vertex region. Alternatively, in some examples, the energy applied to the electrodes closer to the vertex may be higher. In any of these methods, applying energy may include, for example, applying pulsed energy (including but not limited to sub-microsecond, e.g., nanosecond, pulses) including less than 1 ps, 990 ns or less, 950 ns or less, 900 ns or less, 800 ns or less, 700 ns or less, 600 ns or less, 500 ns or less, etc.) electrical pulses. In some of the implementations, the electrical pulse may have an amplitude of at least 0.1 kV (e.g., at least 0.5 kV, at least 1 kV, at least 1.2 kV, at least 1.5 kV, at least 2 kV, at least 5 kV, at least 7 kV, 10 kV, 15kV, 20 kV, etc.).

[0034] Any of these methods may include positioning the tissue or having the tissue positioned between the arms. In some examples the tissue may be a cardiac tissue, and the method may include having the tissue positioned between the first and second arms. In any ofthese methods positioning the tissue may include closing the first and second arms against the tissue, for example, in a scissoring manner.

[0035] Any of these methods may alternatively or additionally include treating the tissue between the arms by applying energy to subsets of the plurality of electrodes after the plurality of electrodes have been divided up into smaller subsets, wherein applying the energy include sequentially applying the energy to each or some of the subsets of the plurality of subsets of electrodes in order to treat the tissue. Dividing the plurality of electrodes into smaller subsets of electrode and separately applying the pulsed electrical energy to the individual subsets may reduce the energy requirement (e.g., at a particular point in time), while allowing treatment of the entire length of the tissue between the arms without having to move the tissue or the arms. For example, any of these methods may include: identifying a plurality of subsets of electrodes from a plurality of electrodes that are arranged on a first arm and / or a second arm of an applicator, wherein the plurality of subsets of electrodes are positioned along at least a portion of a length of the first arm and / or the second arm between a proximal end and a distal end of the respective arm; and treating a tissue held between the first arm and the second arm by sequentially applying electric pulses (e.g., microsecond or sub-microsecond pulses) to each or to at least some of the subsets of electrodes. In any of these methods the arms may open and close in a pivoting manner or may be configured to be parallel to each other when open and close.

[0036] Also described herein are apparatuses adapted to perform these methods. For example, an apparatus for delivering pulsed electrical energy may comprise: a first arm having a proximal end and a distal end; a second arm having a proximal end and a distal end; a plurality of electrodes positioned along at least a portion of a length of the first arm between the proximal end and the distal end; and an energy controller configured to sequentially apply energy to a plurality of subsets of the plurality of electrodes, so that high field- strength electric pulses are applied at different regions along the length of the first arm at different times. In some implementations the apparatus may also comprise an arm actuator configured to adjust a relative position (e.g., spacing) between the first arm and the second arm and / or a position sensor to sense a relative position between the arms.

[0037] In some examples the method or apparatus may use only the subset(s) of electrodes (or electrode pairs) that are contacting tissue. For example, described herein are methods including determining which electrodes on the first arm and / or the second arm are in contact with the tissue so that energy may be applied just between the subsets of electrodes that are in contact with the tissue. In some examples the method may include applying submicrosecond pulsed energy (e.g., activating) to just the electrodes that are in contact with thetissue, or just the electrodes that are capable of applying energy to the tissue in a desired region (e.g., the mid-region through the tissue held between the arms of the apparatus). For example, any of these methods may include applying energy between pairs of electrodes by applying energy between only pairs of electrodes in contact with the tissue. Thus, any of these methods may include sensing contact between a subset of the electrodes and applying energy just to this subset of electrodes. The energy controller may also be configured to determine which subset of electrodes are in contact with the tissue, e.g., by examining one or more electrical properties (impedance, resistance, capacitance, etc.), for example, in response to a test pulse or pulses of energy (typically much lower energy, e.g., less than 0.1 kV, less than 0.5 kV, less than 1 kV, less than 0.09 kV, less than 0.08 kV, less than 0.07 kV, less than 0.06 kV, less than 0.05 kV, etc.). The energy controller may further determine which subset of electrodes to apply energy and in some variations may modulate the applied energy based on the angle between the arms. In some examples the methods and / or apparatuses may determine which subset of electrodes to apply energy to in order to treat tissue (and limit or prevent arcing by only applying high-energy sub-microsecond pulses to those electrodes in sufficient contact with the tissue), even if the applied energy is not modulated based on the arm angle.

[0038] For example, an apparatus as described herein may be configured to limit the energy applied to just a subset of a plurality of electrodes positioned between the arms. The apparatus may dynamically determine the subset, e.g., in real time, based on the subset of electrodes that are in contact with a tissue (including, but not limited to cardiac tissue). For example, an electrode apparatus for delivering pulsed electrical energy may include: a first arm having a proximal end and a distal end; a second arm having a proximal end and a distal end; a plurality of electrodes positioned along at least a portion of a length of the first arm between the proximal end and the distal end; and a controller configured to apply energy to the plurality of electrodes, wherein the controller is configured to detect a subset of the plurality of electrodes that are in contact with a tissue, and to limit the applied energy to the subset. Other exclusion criteria may be applied by the methods and apparatuses described herein, not limited to a lack of contact with the tissue. In some implementations, the apparatus may comprise an arm actuator configured to adjust a relative position between the first arm and the second arm. In some cases the system may not be able to provide sufficient energy, as estimated by the system or device based on the electrical properties of the electrodes and / or the tissue, including but not limited to, the fat content of the tissue to be treated. In any of these apparatuses and methods, the applied energy may be applied sequentially in order to maintain the applied power within a desired range. For example, ifthe impedance of the electrodes treating concurrently (e.g., at the same time) is below a threshold, e.g., where the generator cannot provide the necessary power (voltage times current) to treat the tissue along the length of the entire arm, then these apparatuses may be configured so that subsets of electrodes could be multiplexed such that only individual electrode pairs (or some number of pairs) are activated separately. This may reduce the required power (voltage times current) down to the level that the generator can more easily provide.

[0039] In any of these apparatuses the controller may be configured to detect the subset of the first plurality of electrodes based on impedance values for the electrodes of the first plurality of electrodes. As mentioned, the controller may apply one or more pulses of low- powered energy to sense contact with a tissue against one or more electrodes of the arms. In some examples the methods and / or apparatus may include one or more sensors (additional sensors, such as optical sensors, pressure sensors, etc.) to output contact with separate and / or overlapping regions between the arms. The controller may receive and use this sensor information to determine which subset of electrodes to apply the sub-microsecond energy from.

[0040] As mentioned, any of the apparatuses described herein may include a second plurality of electrodes positioned along the length of the second arm from the proximal end to the second end. Energy may be applied between electrodes on the same arm and / or between electrodes on the first arm and electrodes on the second arm. In either case, the energy controller may be configured to adjust the energy applied between pairs of electrodes from the plurality of electrodes positioned along the length of the first arm and the second plurality of electrodes positioned along the length of the second arm that are opposite each other.

[0041] The first arm and the second arm may be configured to pivot relative to each other. In some examples, the arms may be parallel to each other. In some examples the arm actuator may comprise a handle.

[0042] Any of the apparatuses described herein may include a pulse generator operatively coupled to the one or more controller (including an energy controller). The pulse generator may comprise a sub-microsecond, high voltage pulse generator. As mentioned, the first arm and the second arm may be straight, bent or curved. In some examples the first arm and the second arm are 5 cm or longer.

[0043] A method according to the above aspect of the present disclosure may include: identifying a subset of electrodes in contact with a tissue from a plurality of electrodes that are arranged on a first arm of an applicator, wherein the plurality of electrodes are positioned along a length of the first arm from a proximal end to a distal end of the first arm; andapplying energy to just the subset of electrodes on the first arm while preventing energy from being applied to electrodes on the plurality of electrodes that are not part of the subset. Any of these methods may include positioning the tissue between the first arm and the second arm and / or identifying a tissue that is held between the first arm and a second arm of a treatment applicator (or a presence of the tissue between the first and second arms).

[0044] Any of the methods and apparatuses described herein may be configured to apply a consistent field strength and / or ablation pattern. For example, an apparatus may include: a first arm having a proximal end and a distal end; a second arm having a proximal end and a distal end; a plurality of electrodes positioned along at least a portion of a length of the first arm between the proximal end and the distal end; an arm actuator configured to adjust a separation between the first arm and the second arm; a position sensor configured to sense a relative position between the first arm and the second arm; and an energy controller receiving input from the position sensor and configured to adjust the energy applied to the plurality of electrodes positioned along the length of the first arm based on the relative position between the first arm and the second arm to maintain a relatively constant electrical field between the arms and / or maintain a relatively constant region of ablation through a tissue held between the arms by adjusting one or more of: pulse width, pulse amplitude, number of pulses.

[0045] In some cases, the applicator apparatus for delivering pulsed electrical energy may include: a first arm having a first plurality of electrodes positioned along at least a portion of a length of the first arm; a second arm having a second plurality of electrodes positioned along at least a portion of a length of the second arm; an arm actuator configured to adjust a separation between the first arm and the second arm; a position sensor configured to sense a relative position between the first arm and the second arm; and an energy controller receiving input from the position sensor and configured to adjust the energy applied between electrodes of the first and second plurality of electrodes based on a distance between the electrodes of the first and second plurality of electrodes derived from the received input from the position sensor to reduce or eliminate arcing between the electrodes of the first and second plurality of electrodes.

[0046] An applicator apparatus for delivering pulsed electrical energy may include: a first arm having a first plurality of electrodes positioned along at least a portion of a length of the first arm; a second arm having a second plurality of electrodes positioned along at least a portion of a length of the second arm; an arm actuator configured to adjust a separation between the first arm and the second arm; and an energy controller configured to control the energy applied between one or more subsets of electrodes of the first and second plurality of electrodes based on one or more impedance measurements made between the one or moresubsets of electrodes, wherein the energy controller is configured to apply energy between the one or more subsets of electrodes for which the impedance measurement indicate a tissue between the one or more subsets of electrodes and / or a type of tissue between the one or more subsets of electrodes.

[0047] Any of the methods and apparatuses described herein may include a lasso-type applicator. For example, an applicator apparatus for delivering pulsed electrical energy may include: a flexible elongate body; a plurality of electrodes along a length of a first end region of the flexible elongate body; and a lasso connector at an end of the first end region configured to slidingly receive a second end of the flexible elongate body, wherein the second end of the flexile elongate body is configured to be inserted through the lasso connector so that at least a portion of the length of the first end region of the flexible elongate body forms a loop. The apparatus may include a plurality of electrical connectors at a second end region of the flexible elongate body, wherein the plurality of electrical connectors are in electrical communication with the plurality of electrodes. In some examples the loop may be constricted by pulling the second end region through the lasso connector. The plurality of electrodes may be positioned within an inner surface of the loop. The plurality of electrodes may comprise a plurality of pairs of electrodes that are arranged so that members of the pair of electrodes are parallel to each other along the length of the first end region. The lasso connector may comprise one or more electrodes. Any of these electrodes may include a leash coupled to the first end region and / or the lasso connector to open the loop.

[0048] Also described herein are methods of using any of these lasso-type applicators. For example, a method may include: inserting a first length of a flexible elongate body around a tissue; inserting a first end of the first length of the flexible elongate body into a lasso connector at a second end of the flexible elongate body to form a loop; constricting the loop around the tissue; and applying energy between two or more electrodes within the loop to treat the tissue.

[0049] In some implementations, the method may be method of treating a cardiac tissue with a lasso-type applicator. For example, described herein are methods of treating atrial fibrillation or other cardiac arrhythmias, the method comprising: inserting a first length of a flexible elongate body around one or more pulmonary veins; inserting a first end of the first length of the flexible elongate body into a lasso connector at a second end of the flexible elongate body to form a loop; constricting the loop around the one or more pulmonary veins; and applying energy between two or more electrodes within the loop to treat cardiac arrhythmia (e.g., atrial fibrillation). Inserting the first length may include forming the loop and constricting the loop around all four pulmonary veins.

[0050] All of the methods and apparatuses described herein, in any combination, are herein contemplated and can be used to achieve the benefits as described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0051] A better understanding of the features and advantages of the methods and apparatuses described herein will be obtained by reference to the following detailed description that sets forth illustrative embodiments, and the accompanying drawings of which:

[0052] FIG. l is a schematic example of a system for treating patients using the method as described herein.

[0053] FIG. 2 schematically illustrates one example of an apparatus for delivering high filed strength electric pulses (e.g., microsecond or sub-microsecond pulses), in which the apparatus includes a pair of arms (e.g., jaws) with electrodes positioned therebetween.

[0054] FIGS. 3A-3C shows an example of a pair of arms (e.g., jaws). FIG. 3A shows the arms in an open configuration with a tissue between the first and second arms. FIG. 3B shows the arms in a closed position, with the arms closed onto the tissue. FIG. 3C shows an enlarged view of the closed arms of FIG. 3B, illustrating a line or plane of consistent field strength positioned at approximately a middle angle through the tissue between the arms.

[0055] FIG. 4A shows an example of a distal end (e.g., end effector region) of an apparatus similar to that shown in FIGS. 3 A-3C including pairs of electrodes on opposite arms (e.g., jaws).

[0056] FIG. 4B shows an example of a distal end (e.g., end effector region) of an applicator including a plurality of electrodes on one arm and a single electrode on the opposite arm.

[0057] FIGS. 5A-5B illustrate another example of a pair of arms (e.g., of an end effector) that may be used as described herein.

[0058] FIGS. 6A-6B illustrate examples of parallel arms having a plurality of electrodes that may be configured as described herein using an energy controller to control a subset of electrodes along the length of the arms.

[0059] FIG. 7 schematically illustrates one example of a method of treating tissue by delivering high field- strength electric pulses according to the present disclosure.

[0060] FIG. 8 schematically illustrates an example of a method of treating tissue by delivering high field- strength electric pulses to subsets of electrodes from a plurality of electrodes positioned along a long length of one or both arms (e.g., jaws) of a pair of arms.

[0061] FIG. 9 schematically illustrates one example of a method of limiting the application of sub-microsecond pulsed electrical energy to a subset of electrodes from a plurality of electrodes positioned along a long length of one or both arms (e.g., jaws) of a pair of arms.

[0062] FIGS. 10A-10B illustrate an example of an applicator having curved arms (e.g., jaws) and electrodes of different size (and number) on either arm. FIG. 10A is a side perspective view. FIG. 1 OB is a side view.

[0063] FIG. 11 schematically illustrates another example of an applicator.

[0064] FIG. 12 illustrates an example of a lasso-type applicator including a plurality of electrodes arranged on a flexible elongate body that is configured to form a constrictable loop (e.g., lasso) around a tissue to be treated.

[0065] FIG. 13 A illustrates another example of a lasso-type applicator, shown in an undeployed, linear configuration.

[0066] FIGS. 13B-13D illustrate deployment of one example of a lasso-type applicator.

[0067] FIGS. 14A-14C show another example of a lasso-type applicator in a deployed loop configuration in various side perspective views.DETAILED DESCRIPTION

[0068] An apparatus (e.g., system, device, etc., including software, hardware and / or firmware, and in some cases an applicator) for treating tissue by the application of a pulsed electrical energy, including using sub-microsecond pulses, may secure tissue and may control (e.g., adjust) the applied pulsed electrical energy based, for example, on the configuration of the apparatus, and in particular, the relative configuration of the apparatus with respect to the tissue. In some cases, the apparatus may be an applicator having a pair of arms (e.g., jaws) configured to hold or position tissue between the arms or jaws, and the arms or jaws may include a plurality of electrodes. Alternatively, in some examples the apparatus may be an applicator having a single arm (e.g., single jaw) that is configured to form a loop or curve around the tissue (e.g., a lasso-type applicator). In general, these apparatuses may include a plurality of electrodes that are configured to apply electrical energy between pairs of the electrodes of the plurality of electrodes. The plurality of electrodes may be on a surface (flush with the surface, recessed and / or extending above the surface) of the applicator. The apparatus may include a controller that is configured to adjust the applied electrical energy, including the energy applied, and / or selecting which electrodes (including which pairs of electrodes) of the plurality of electrodes to apply energy from, based, for example, on theconfiguration of the applicator and / or the relationship between the applicator (e.g., the electrodes on the applicator) and the tissue.

[0069] The apparatuses and methods described herein may include one or more arms that may equivalently be referred to as jaws. These arms (e.g., jaws) may be configured to contact tissue so that energy may be applied from electrodes on the arm or arms (e.g., jaws). In any of these methods and apparatuses the apparatus may include one or more arms (e.g., jaws) that are configured to be positioned at least partially around the tissue; energy applied between a pair of electrodes may thus be transmitted through the tissue on either side of the arm or arms.

[0070] For example, described herein are methods and apparatuses in which the energy applied to the different pairs or subsets of electrodes (e.g., of the arm / arms, or jaw / jaws, including a lasso-type applicator) may be controlled and adjusted. The methods and apparatuses of the present disclosure may also be configured to minimize the likelihood of arcing when applying the sub-microsecond or microsecond pulsing, for example, by applying energy to just those electrodes having sufficient contact with the tissue. Further, described herein are methods and apparatus in which the energy is applied to a subset of the electrodes along the length of the applicator, e.g., in some example along the length of an arm (or arms / jaws) of the applicator, for example, to match impedance of the electrodes to the impedance of the pulse generator, especially microsecond and / or sub-microsecond pulse generator. Such methods and apparatuses (e.g., systems) allow to produce effective ablative lesions by activating different portions of the arm length at different times to treat the whole area without repositioning the arms (e.g., jaws).

[0071] Thus, the methods and apparatuses described herein may provide a predictable, and in some cases even, or approximately evenly distributed, treatment of tissues having different thicknesses and / or compositions. This may be achieved in any of the methods and apparatuses described herein by using a plurality of electrodes arranged along a length (and / or in some cases, a breadth) of an applicator between which tissue may be positioned. As mentioned, these methods and apparatuses may adjust the energy applied between subsets of the plurality of electrodes based on the configuration of the applicator (from which a thickness of the tissue and / or spacing of the electrodes may be derived) in order to provide a desired ablation within the tissue.

[0072] In some examples described herein, the applicator may include a pair of arms (e.g., jaws); electrodes may be arranged on opposite sides of a pair of arms. The arms may be scissoring, and may diverge at an angle relative to each other about a pivot or fulcrum point or region. The arms may be opened or closed to a greater or lesser degree, which mayincrease or decrease the separation between the electrodes. The tissue held between the arms may also have a different, e.g., varying, thickness. In examples in which the arms pivot about a fulcrum (e.g., like scissors) the spacing between the electrodes on opposite arms may increase or decrease. In order to maintain a consistent electric field (and / or a consistent ablation), the methods and apparatuses described herein may vary the voltage along the length of the arm by controlling the voltage applied between different pairs of electrodes. In some cases the electric field between the electrodes may be estimated as the voltage applied to the electrode pair divided by the distance between the electrode pair. For example, the apparatuses and methods described herein may scale the applied energy based on the difference in separation between the various pairs of electrodes (e.g., in some cases, along the length of the arms).

[0073] As mentioned, the configuration of the applicator may include the positions of the arms or jaws, and therefore, electrodes relative to each other. For example, the relative arm positions may be used to determine the distance between the arms and may, therefore, estimate or approximate the thickness of the tissue between the arm, and / or the separation between electrodes that may be used as electrode pairs to apply energy to the tissue held between the arms. In some cases these methods and apparatuses may include non-scissor arms. For example, parallel arms may be used, including very long arms, e.g., the arms / jaws may be so long that they bend or diverge distally, in some cases due to cantilever beam bending, and the methods and apparatuses described herein may characterize that bending and with different electrodes along the length of the diverging “parallel” arms the voltage can be changed to control the electric field, including keeping it more consistent. In any of these apparatuses and methods the energy applied between different subsets of electrodes may be adjusted in order to keep the electric field approximately constant and / or the alation of the target tissue (for example, width of the ablation) relatively consistent.

[0074] The methods and apparatuses described herein may allow control over how energy is delivered to different parts of the applicator (e.g., electrodes, etc.). In examples having diverging arms, the methods and apparatuses described herein may maintain a relatively constant electric field by increasing the voltage as the arms diverge. In some examples these methods and apparatuses may maintain a relatively constant energy density in the thicker tissue by increasing the pulse width as the distance between the electrodes diverge. Alternatively or additionally, these methods and apparatuses may maintain a relatively constant energy density in the thicker tissue by adding more pulses as the distance between the electrodes (e.g. in some cases the distance between the arms) diverge. In general,these methods may allow for combinations of changing the energy along the path of the arms or the length of the apparatus.

[0075] In some examples, these methods may include decreasing the energy applied (e.g., voltage applied, current applied, etc.) near the intersection (e.g., pivot, fulcrum, etc.) between the arms supporting the plurality of electrodes, in order to reduce arcing while still maintaining a higher voltage further away from the region(s) where the electrodes are closer together, such as the intersection. In many of the methods and apparatuses described herein, each electrode pair may be controlled independently and the impedance in each electrode pair may be measured and used to determine if the tissue is in contact with only part of the applicator, so that the applicator may deliver energy exclusively or primarily where the tissue is in contact with the applicator (e.g., the electrodes of the applicator) and may not deliver energy to the electrodes that are not contacting tissue.

[0076] Alternatively or additionally, in some cases measuring impedance in each electrode pair of the plurality of pairs may be used to determine if part of the applicator device, including electrodes of the applicator, are contacting a first type of tissue (e.g., skin, muscle, etc., non-fat tissue, fat tissue, etc.) and if other parts of the applicator are contacting a second type of tissue (e.g., skin, muscle, fat tissue, non-fat tissue, etc.). The type of tissue (or the change in the type of tissue, which may not require identifying a particular type of tissue), may be used to adjust the applied energy that is applied by the electrodes. For example, the portion of the applicator (e.g., arms) having electrodes in contact with fat tissue may be pulsed with a higher voltage and / or energy to create a higher electric field in order to treat the tissue beyond the fat. Alternatively, in some examples region(s) without fat may be pulsed with lower energy and / or voltage to treat the tissue.

[0077] For example, according to some examples, described herein are apparatuses (e.g., devices and systems, including software, hardware and / or firmware) having a pair of arms (e.g., jaws) with electrodes for delivering high field- strength pulses of electrical energy to treat a tissue held between the arms of the apparatus, and a controller configured, among other things, to adjust the energy applied to pairs (or individual) electrodes based on the angle of the arms and / or based on contact with tissue between the arms. The angle of the arms may be used as, or may be a proxy for, the separation between the electrodes of a pair of electrodes, and / or the thickness of the tissue to be treated. For example, these apparatuses may include arms that can be opened and closed by changing the arm angle between the arms, and a controller (e.g., an energy controller) that may adjust the energy applied to the electrodes at different positions on the arms, including at different separation distances between the electrodes, based on the arm angle. The controller may therefore compensate forthe different distances between electrodes on the arms, which may change depending on an angle between the arms to provide a relatively uniform electric field in a plane or line through the tissue between the arms. The high field- strength pulses may be sub-microsecond (e.g., nanosecond) pulses. The angle between the arms may be a compound angle, particularly where the arms may include multiple bending or curved regions. Thus, in some cases the angle between the arms may refer to the net angle between the electrodes on the arms; as mentioned above, the arm angle may be used to determine the separation between the various electrode pairs that may be used to apply energy.

[0078] Thus, in some examples the apparatuses described herein may include an applicator (e.g., having a pair of arms) including or configured for use with an energy controller. Any of these apparatuses may be configured to be used with and / or includes a pulse generator for applying pulses, such as sub-microsecond pulses. The controller (also referred to in some examples herein as an energy controller) may be integrated with the applicator and / or with the pulse generator; in some examples the controller is separate from, but connected to, or configured to connect to, applicator and / or pulse generator.

[0079] The pulse generator may be configured to generate a plurality of electrical pulses, such as those having an amplitude of at least 0.1 kV and a duration of less than 1000 nanoseconds. The system may include a connector, e.g., a high voltage connector adapted to couple the elongate applicator tool to the pulse generator. The pulse generator may include a port configured to connect to the high voltage connector.

[0080] FIG. 1 illustrates one example of a system 100 (also referred to herein as a high voltage system or a sub-microsecond generation system) for delivering high voltage, fast (e.g., sub-microsecond) pulses of electrical energy that may include an applicator 102 configured as described herein. The systems described herein may include any of the applicators shown and described herein, including applicators having arms, as well as applicators configured to form a curve or loop (e.g., lasso-type applicators). In FIG. 1, the applicator example shown has a pair of arms, a pulse generator 107, footswitch 103, and user interface 104. The controller (e.g., energy controller) may be part of the pulse generator 107 and / or part of the applicator 102 or separate from them. The system 100 may provide the high voltage electrical energy pules to treat tissues, including tissues of one or more organs (e.g., heart, pulmonary veins, pharynx, esophagus, stomach, small intestine, large intestine, liver, gallbladder, mesentery, pancreas, larynx, trachea, bronchia, lungs, diaphragm, kidney, bladder, urethra, ovaries, fallopian tubes, uterus, vagina, testes, epididymis, vas deferens, prostate, bulbourethral glands, pituitary gland, pineal gland, thyroid gland, adrenal glands, arteries, veins, lymph nodes, lymphatic vessel, spleen, thymus, skin, eyelids, lips, tongue, ear,nose, vocal cords, etc.). In some examples the apparatuses and methods described herein may be used to treat one or more of these tissues, in some examples as part of a minimally invasive therapy. The methods and apparatuses described herein may be used to treat circulatory system tissue (e.g., heart, artery, vein, etc.). As stated above, in some examples the methods and apparatuses described herein may be used to treat a tumor or tumors, including cancerous, pre-cancerous, benign or non-malignant tumors, lesions or growths. In some other examples, the methods and apparatuses described herein may be used to treat any feasible tissue or cell. Non-limiting examples of pulse generators that may be used with any of the apparatuses (e.g., systems) described herein may include, but are not limited to, those shown in U.S. patent 11,696,800 (“High-Voltage Analog Circuit Pulser”, U.S. patent 11,452,870 (“Nanosecond pulsed power sources having multi -core transformers”), and U.S. patent 11,723,712 (“High-Voltage Analog Circuit Pulser and Pulse Generator Discharge Circuit”), each of which is herein incorporated by reference in its entirety.

[0081] In some examples the apparatus includes one or more inputs, such as a footswitch 103, shown in FIG. 1 as connected to housing 105, which may enclose the electronic components, including controller and / or sub-controllers, including but not limited to the energy controller. The footswitch in FIG. 1 is connected to the controller through a cable and connector 106. The elongate applicator tool 102 includes a pair of arms 114, 116 which may include electrodes and is connected to housing 105 and the electronic components therein through a cable 137 and high voltage connector 112. The high voltage system 100 may also include a handle 110 and storage drawer 108. The system 100 may also include a holder (e.g., holster, carrier, etc.) (not shown) which may be configured to hold the elongate applicator tool 102.

[0082] A human operator may select a number of pulses, amplitude (e.g., voltage amplitude and / or current amplitude), pulse duration, and frequency information for a target treatment, for example by inputting such parameters into a numeric keypad or a touch screen of interface 104. The apparatus may adjust or vary these parameters as described herein, e.g., to control the energy applied thought the arms. In some examples, the pulse width can be varied. A controller may send signals to pulse control elements within system 100. In some examples, fiber optic cables are used which allow control signaling while also electrically isolating the contents of the metal cabinet with sub-microsecond pulse generation system 100, e.g., the high voltage circuit, from the outside. In some examples the system 100 may be battery powered and / or may be powered from a wall outlet.

[0083] The applicator tool 102 may be hand-held (e.g., by a user) or it can be affixed to a movable arm of a robotic system, and its operation may be at least partially automated or fully automated, including computer-controlled.

[0084] FIG. 2 schematically illustrates another example of an apparatus 200, including one example of an applicator 202 connected (via connector 219) to an energy controller 213 which may be part of or may be coupled to a pulse generator 217. The apparatus shown in FIG. 2 is configured for delivering, for example, sub-microsecond electrical pulses to a tissue held between the arms (e.g., jaws) 203, 205. In this example, the applicator includes a first arm 203 having a proximal end and a distal end and a second arm 205 having a proximal end and a distal end. The second arm 205 is hinged relative to the first arm 203, and both the first 203 and second 205 arms extend distally from an elongate body 209. Alternatively, the first arm may be movable relative to the second arm, or the first and second arms may both be configured to move relative to each other and / or relative to the elongate body. The elongate body 209 may be rigid or flexible (e.g., bendable) and may be straight or curved. The arms may be opened or closed by actuating an arm actuator 211, shown in this example on a proximal end region of the elongate body 209. The arm actuator may be any appropriate control. In this example the arm actuator 211 is a lever or trigger that may be operated by a user’s hand (e.g., fingers) while holding the elongate body 209. At least one arm (e.g., first arm 203 and / or second arm 205) may include a plurality of electrodes 207 extending down the length of the arm. FIG. 2 is not shown to scale. For example, the elongate body may be longer or shorter (straight or curved), the arms may be longer or shorter (straight or curved), and the electrodes may be larger or smaller. In some examples more or fewer electrodes may be included.

[0085] In general the connector 219 may be part of the applicator (e.g., one end of the elongate body of the applicator) or may be separate, and may couple to the applicator so that the electrodes of the plurality of electrodes may be separately or collectively (or sub-sets of the electrodes) may be addressed or addressable by the controller (energy controller 213). In some cases the connector may include a plug, clip, insert, etc. for coupling to the controller. As described herein, in some cases the applicator may be integrated with the controller, thus the connector may be optional and / or fully internal.

[0086] In the example shown in FIG. 2 the plurality of electrodes 207 positioned along a length of the first arm 203 may be held against a tissue between the arms. The arm angle 215 between the first 203 and second 205 arms may be adjusted by operating the arm actuator 211. For example, FIGS. 3 A and 3B illustrate the arms of FIG. 2 shown in an open (FIG. 3 A) and partially closed (FIG. 3B) configuration, shown clamping onto a region of tissue 321.

[0087] In FIG. 3A the first arm 303 and second arm 305 may both include a plurality of electrodes along the length of the arms (e.g., jaws), or just one of the arms may include electrodes. In FIG. 3 A the tissue 321 is positioned between the arms, but the arms are opened, having a first arm angle 315. In any of these apparatuses the arms may be biased open, biased closed, or maintained in a neutral position unless actuated open or closed. In FIG. 3B the arm angle 315’ has been reduced by actuating the arm actuator to adjust an angle between the first arm and the second arm, closing the arms onto the tissue 321. The arms may be closed onto the tissue to compress the tissue somewhat. In any of these examples the amount of force applied, e.g., by the arm actuator 211, may be limited, in order to prevent or limit damage to the tissue. For example, the apparatus may include a force sensor configured to detect the clamping force of the arms. In FIG. 3B, with the arms shut onto the tissue, only a subset of the electrodes 304 of the first arm 303 are in contact with the target tissue between the arms. Although not visible in FIGS. 3A-3B, in some cases the second arm 305 may also include a plurality of electrodes, a subset of which may contact the tissue when the arms are closed against the tissue. The arm angle may be detected by a position sensor (e.g., arm angle sensor) that is configured to sense the angle between the first arm and the second arm.

[0088] In general, the apparatuses and methods described herein may be configured to include and use a position sensor that may detect position information on the applicator (e.g., the elongate body, the one or more arms, etc.) reflecting the relative positions of the electrodes to each other and / or to the tissue held by the applicator. In some cases, the position sensor may be an angle sensor, e.g., arm angle sensor.. Examples of position sensors may include, but are not limited to, magnetic position (e.g., angle) sensors, capacitive sensors, photoelectric sensors, eddy current sensors, linear sensors, position encoders.

[0089] As shown in FIG. 3C, the apparatus may be configured to apply energy (e.g., a sub-microsecond pulsed energy), between pairs of electrodes of the first plurality of electrode on the first arm, and / or between electrodes on the first arm 303 and electrodes of a second plurality of electrodes on the second arm 305 (not visible in FIG. 3C). The apparatus, e.g., the energy controller of the apparatus, may be configured to receive the position information, such as arm angle, from the position sensor (or any other arm angle determination mechanism), and may adjust the energy applied to the plurality of electrodes positioned along the length of the first arm based on the angle between the first arm and the second arm and / or based on the separation between electrodes used to apply energy. The energy controller may adjust the energy applied between electrode pairs in order to maintain a consistent electrical field, and / or to achieve a relatively consistent ablation pattern (e.g., ablation width, depth, etc.) and / or to prevent or reduce arcing. In some examples the controller (e.g., energycontroller) is configured to deliver a relatively consistent (e.g., nearly constant) electrical field, for example, in a line or plane 335 extending through the tissue between the arms as seen in FIG. 3C. In general, the apparatuses and methods described herein may adjust one or more electrical parameters (e.g., pulse duration / pulse width, amplitude, e.g., current and / or voltage amplitude, pulse frequency, etc.) in order to maintain the target electric field, target ablation and / or to prevent arcing. The controller (e.g., energy controller) may adjust one or more electrical parameters for each pair of a plurality of pairs (subsets) of the plurality of electrodes in order to achieve the more uniform electric field and / or ablation effect. For example, more distal electrode pairs may apply a relatively higher voltage to maintain a consistent electric field where the more distant electrode pairs have a greater separation (e.g., in scissoring arm applicators).

[0090] The energy controllers described herein may therefore adjust the applied energy so that a more consistent energy is applied when desired. The controller may adjust the applied energy by adjusting one or more electrical parameters, as discussed above. In some examples the controller may calculate values for one or more electrical parameters for each of the plurality of pairs of electrodes in order to achieve the target effect (e.g., consistent applied field, consistent ablation pattern, preventing arcing, etc.). The controller may estimate or calculate a predicted target effect based on the position information (e.g., arm position, electrode separation, etc.) and / or may solve for the electrical parameters need to achieve the target effect. In some cases the controller may include one or more estimation modules for estimating one or more electrical parameters given a target effect. In some cases the controller may include one or more trained machine learning agents configured to receive position information (and in some cases, target effect) and may output the one or more electrical parameters to achieve the target effect.

[0091] In FIG. 3C a line (or in some examples, plane) of consistent field strength extends through the tissue at an angle that is, in the example shown in FIG. 3C, approximately halfway through the arm angle. The angle of this line of consistent field strength may be referred to for convenience as a consistent field angle and may be set or adjusted. In some examples a line of consistent field strength may be, e.g., a line coincident with the opposing arm.

[0092] In any of these methods and apparatuses the energy applied by the device may be adjusted to adjust the field strength between the arms (e.g., jaws) based on the angle between the arms and / or the material properties (e.g., region electrical properties such as impedance, etc.) between pairs of electrodes on the arms. For example, the field strength may be increased or decreased based on the angle and / or the material properties. In FIG. 3C theconsistent field strength line 335 is shown as a straight line extending in a consistent angle; however, the consistent field strength line may be curved or bent, e.g., having a varying angle. In some examples the field strength line (or plane) may be parallel to one of the arms. In general, the method or apparatus may determine the angle between the arms as described above. The angle between the arms may also be used to estimate a thickness of the tissue between the arms.

[0093] The energy controller may adjust the field strength by increasing the energy applied between the arms as electrode pairs are further from the vertex of the arms (e.g., the intersection of the first and second arms / arms) as a function of the arm position (e.g., arm angle). As mentioned above, this adjustment may be based on a simple linear adjustment or may be based on a model of the field (and / or ablation), and / or may be based on a trained machine-learning agent. In general, the greater the arm angle, the greater the increase with distance from the vertex. As mentioned, this relationship may be, e.g., determined empirically, or may be modeled and / or calculated, e.g., assuming the dielectric properties of the tissue, such as cardiac tissue. In some examples the increase in applied energy, and therefore resulting field strength, between the electrodes is a function of distance from the vertex and the angle of the arms. In general this function may result in increasing the applied energy to the electrodes (e.g., between pairs of electrodes) as the electrodes extend away from (e.g., distally) the vertex and as the angle increases.

[0094] Adjusting the applied energy to the electrodes as based on the angle and the distance from the vertex may help the apparatus to adjust the electric filed between the arms (e.g., jaws) as desired, for example, to create a consistent electric field through the tissue between the arms, and may prevent non-uniform electric field regions. For example, simply applying the same energy between pairs or electrodes (e.g., on opposite sides of the arms) may result in some of the tissue being ablated more than others, an effect which is increasingly seen as the separation between active (e.g., energy applying) electrode pairs increases, e.g., as arm angle increases. This may also result in a higher chance of arcing, and therefore, damage to the tissue and / or applicator. For example, the apparatus, and specifically the energy controller, may be configured to adjust the pulse count and / or kV between electrode pairs to change the treatment intensity at different positions within the arm. The energy controller may adjust the magnitude of the energy applied, and / or the pulse length and / or the number of pulses.

[0095] For example, in FIG. 4 A, the applicator may apply energy from each of a plurality of pairs of electrodes. Although the individual electrodes may be multiplexed in a variety of different ways, in some cases pairs of electrodes may be arranged across from each, onopposite sides of a target tissue. In the example shown in FIG. 4A the electrode pairs may include, in order of the distance from the vertex of the arms, a first electrode pair 431, 433, a second electrode pair 434, 436, a third electrode pair 437, 438, a fourth electrode pair 439, 440 and a fifth electrode pair 441, 442. The electrode pairs may be configured so that each of the electrode pairs are on their own circuit. In this example, the energy controller may be configured to apply less energy to the first (most proximal, e.g., closest to the vertex) pair of electrodes 431, 433. The controller may apply the greatest energy to the last, e.g., most distal electrode pair 441, 442. The arrows between electrode pairs in Fig 4A illustrate examples of electrical field lines 435, and less energy needs to be applied to the proximal pair and more energy needs to be applied to the distal pair.

[0096] In a simplified example, if the distance between a more proximal electrode pair (e.g., 431, 433) is approximately one half of the distance between a more distal electrode pair (e.g., 434, 436), then the voltage applied to the more distal electrode pair may be double that of the proximal electrode pair to have a comparable electric field between each discrete set of electrodes.

[0097] In any of these apparatuses the individual electrodes of the plurality of electrodes, on either or both the first arm and the second arm, may be individually controlled and may therefore be independently wired. Either or both the first arm and the second arm may be used to apply an electric field through the tissue, e.g., to create a lesion in the target tissue. If both the first and second arms include a plurality of electrodes, then both the first and second arms may be used to create the electric field. Alternatively, electrode pairs on just one arm including a plurality of electrodes can be activated to apply an electric field and / or treat a tissue between the arms from one side only. In operation these applicators may apply an electric field that may penetrate into the tissue and the decaying electrical field may cause killing cells. Depending on the pulse duration and applied energy, cells death may be triggered non-thermally, e.g., up to an electric field threshold; electric fields stronger than this threshold may kill the cells, and electric fields weaker than this threshold may not kill the cells. The magnitude of the field threshold may be a function of the energy delivered.

[0098] As mentioned above, in some examples the apparatuses may be configured to use the arm angle information (e.g., from an angle sensor) to calculate the distance between pairs of electrodes, through which energy is being applied, and may adjust the applied energy according to this distance. For example if the first electrode of the first plurality of electrodes is paired with the first electrode of the second plurality of electrodes, the angle between the arms (e.g., jaws) may be used to determine the spacing between the electrodes; as the arm angle increases, the more distal electrodes would be farther apart. To create a consistentelectric field over the length of the arm, the energy controller may drive the most distal electrode pair at the highest kV, then closer to the root of the scissor is lower and lower kV. The lowest kV would be at the most proximal electrode pair. In some examples the energy controller may adjust the field strength for tissue centered between each electrode pair.

[0099] In FIG. 4A, the example applicator includes a distal end region having a first arm 403 and a second arm 405 in which the first and / or second arms may scissor open / closed relative to each other. As mentioned above, the apparatus may include a position (e.g., angle) sensor 467 that may detect the arm angle 415 between the arms. The arms may extend distally from a distal end region of a shaft 409 (e.g., an elongate body). In practice, in different implementations, various combinations of electrode polarities may be used. In some examples, the first set of electrodes (e.g., on one arm) may be configured to have a first polarity (e.g., +), while the second set of electrodes (e.g., on the second arm) may have a second polarity (e.g., -). In some other examples, the first set of electrodes may alternate in polarity between adjacent electrodes extending down the length of the first arm, and the second set of electrodes may alternate in polarity (e.g., +, -, +, -, etc.) between adjacent electrodes extending down the length of the second arm.

[0100] In the example of FIG. 4 A the polarity of the electrodes extending along the first arm is opposite to the polarity of the electrodes extending along the second arm, and the lines 435 shown illustrate the field between the pairs of electrodes (applied between pairs of electrodes on each the first and second arms). The arm angle 415 may be adjusted, and as the arm angle is adjusted, the field strength may be adjusted as described.

[0101] FIG. 4B shows another example of a distal end of an applicator including a pair of arms (e.g., jaws) (e.g., a first arm 403’ and a second arm 405’) that are similar to the example shown in FIG. 4A, but wherein a different number of electrodes may be present on the upper arm 405’ as compared to the lower arm 403’. Thus, in FIG. 4B, the applicator has a single long electrode on one arm, and the other arm has a plurality of electrodes. In this example, the electrodes on the first arm may be paired with the same electrode on the second arm. For example, the long electrode could function as a common ground and the plurality of small electrodes could have different applied voltages. In some examples the controller (e.g., energy controller) may control a multiplexer to determine which electrodes to pair and to apply energy between. Alternatively or additionally, as mentioned above, in some examples electrodes may be paired together as part of a circuit. In general, these applicators may include arms having unequal numbers of electrodes.

[0102] In some examples the electrodes of an applicator as described herein may all be present on the same circuit, however each electrode pair may have a different resistor inseries with that pair. For example, the proximal-most electrode pair (e.g., in FIG. 4A 431, 433) may have the highest resistor value in series so that more voltage may be dropped across that resistor, and as a result, less voltage may be transmitted to the next proximal-most electrode pair. This cascading resistance pattern may be repeated down the proximal -to-distal sequence, so that the distal-most electrode pair (e.g., in FIG. 4A 441, 442) has the lowest resistor value in series, so that less voltage is dropped across its resistor in series, and therefore more voltage may be passed to the distal-most electrode pair.

[0103] In some examples each resistor may be configured as a variable resistor and so as the arm angle changes the resistor values may change to keep the electric field consistent (e.g., each variable resistor may be configured to have a different rate of change because the distance between the distal electrodes may change at a greater rate for the distal electrode pairs as compared to the proximal electrode pairs). This configuration may be referred to as a cascading variable resistance configuration and may be configured by hardware, software, and / or firmware. For example, the energy controller may be configured to adjust the variable resistance for each pair of electrodes in the series circuitry. Alternatively, the resistance may be proportionally adjusted for each of the pairs of electrodes using amplifier circuitry.

[0104] FIGS. 5A and 5B illustrate other examples of the distal end region of an applicator including a pair of arms 503, 505. In FIG. 5A the first arm 503 and / or the second arm 505 may pivot or scissor relative to each other to open / close the arms. In this example both the first arm 503 and the second arm 505 may include a plurality of electrodes. The polarity of the plurality of electrodes may alternate on both the first arm and the second arm (not shown), or the polarity (e.g., +) of the electrodes 533 on the first arm may be the same along the first arm, but the polarity of the electrodes 531 on the second arm may be a different polarity (e.g., -) as seen in FIG. 5A so that energy may be applied between pairs of electrodes (one from the upper arm and one from the lower arm). FIG. 5B shows an example of a distal end of an applicator that also includes a first arm 503’ and a second arm 505’, which are configured to pivot or scissor open / closed (adjusting the arm angle therebetween), but in in FIG. 5B the plurality of electrodes are arranged only along the first arm 503’ and the polarity of the arms may be alternating; for example, electrodes configured to have a first polarity 533’ are arranged along the length to alternate with electrodes configured to have the second polarity 531’.

[0105] In general, these methods and apparatuses may control the spacing between electrodes of an electrode pair when determining which electrodes to apply energy to. For example, in FIG. 5B the electrodes may be arranged along the length of the arm and pairs of electrodes may be selected from non-adjacent electrodes. For example, an electrode pair maybe formed from a first electrode 533’ and a third electrode 534’ without using the intervening electrode(s) (e.g., electrode 531’ in FIG. 5B). Adjusting the spacing in this manner may change the depth of penetration of the applied electrical field; the applied energy (e.g., voltage) may also be adjusted. The polarity of the electrodes may be adjusted.

[0106] Also described herein are apparatuses (including any of those described in FIGS. 1-5B, above) in which the energy controller is adapted to limit the application of electrical energy (e.g., sub-microsecond pulses) to a subset of the plurality of electrodes. As illustrated in the example of FIG. 3C, with the arms closed, only a subset 304 of the electrodes are in contact with the tissue. The energy controller may determine which electrodes form this subset of electrodes in contact with tissue and may limit the application of energy to this subset.

[0107] In general, according to one aspect of the present disclosure, only a part of the arm can be activated to apply sub-microsecond pulsed energy. This may dramatically prevent or mitigate arcing when applying the sub-microsecond pulsing. This may also allow treatment from a portion of the length of the arms (e.g., jaws). It may be beneficial to include relatively long arms, which may allow treatment of potentially larger regions of tissue. For example, clamping applicators having long arms may be used to treat all the way around all 4 pulmonary veins in a single application. Longer length arms may be significantly longer than more typical arms (e.g., between about 4-20 cm, between about 5-17 cm, between about 5-15 cm, etc. Longer electrodes may have more surface area and may need more energy to drive through them. Existing microsecond or sub-microsecond pulse generators may not be able to provide sufficient current thru the entire long electrodes (may not have sufficient energy). The apparatuses described herein may overcome this issue. In any of these apparatuses and methods multiple electrodes arranged along one or both arms may be used as individual pairs and / or may be multiplexed and treat different portions in series, for example, treat distal end, then middle, then proximal end region. In general, individually controlling each electrode (electrode pair) or a group of electrodes may advantageously allow treatment of long regions without requiring the higher energy levels needed for much longer (and larger surface area) electrodes.

[0108] Thus, in general, these apparatuses may be configured to apply energy between subsets of electrodes along the length of the apparatus, either to sequentially treat different regions and / or to treat just regions in contact with the tissue. This technique may be applied both to scissoring and non-scissoring arms (e.g., parallel arms / arms). For example, FIGS. 6A- 6B illustrate parallel arms that may clamp. For example, in FIG 6A the first arm 603 is parallel with the second arm 605 and both are attached to the elongate body (e.g., shaft 609).An actuator (see, e.g., FIG. 2) may be used to adjust the spacing between the arms, increasing or decreasing the distance. The energy controller may adjust the energy applied (in this example, between the pairs of the upper and lower electrodes by the same amount) based on the spacing distance between the arms. The polarity of the electrodes may be all the same polarity or may alternate polarity along the length of the arms. In the example of FIG. 6A the plurality of electrodes along the first arm 603 are all the same (first, e.g., +) polarity 633, and the plurality of electrodes along the second arm 605 are all the same (second, e.g., -) polarity 631. In operation, the energy controller may apply energy (shown by the field lines 635) to just subsets of electrodes (electrode pairs) between the arms. For example, the energy controller may be configured to separately and sequentially apply energy between pairs of electrodes or subsets of pairs of electrodes along different regions of the lengths of arms (e.g., proximal, mid-proximal, middle, mid-distal, and distal regions). In some examples, while multiple subsets of electrodes along these regions may be all in contact with tissue, the energy controller may be configured to activate only one of these subsets of electrodes along just one of these regions in order to provide sufficient energy for effective ablation. In other examples the apparatus may first determine which subset(s) of electrode pairs are in contact with the tissue and may limit the application of energy to just the electrode pairs that are in contact with the tissue. This may be done using one or more sensors (e.g., contact sensors, optical sensors, etc.) and / or by using the individual electrodes or electrode pairs as sensors. For example, the energy controller may apply energy to individual electrodes (or groups, e.g., pairs, of electrodes) to measure an electrical property such as capacitance, inductance, resistance, impedance, etc., and compare this to an expected value for tissue. Alternatively, in some examples the electrodes may detect electrical activity consistent with a target tissue passively, e.g., by sensing electrocardiographic energy (ECG) or the like.

[0109] FIG. 6B shows another example of an applicator in which the plurality of electrodes are arranged just along the first arm 603’. In this example the plurality of electrodes may be configured so that the polarity of the electrodes alternates between a first polarity 633’ and a second polarity 631’ along the length of the first arm (applied energy is shown by the field lines 635’). The second arm 605’ does not include a plurality of electrodes. As in FIG. 6A, the apparatus may be configured to control the application of energy (e.g., sub-microsecond pulsed energy) to subsets of individual electrode pairs (including single electrode pairs, 2 electrode pairs, 3 electrode pairs, 4 electrode pairs, etc.). The subsets of electrode pairs may be sequentially actuated so that the pulse generator does not have to drive actuation of electrode pairs along the entire length for the arms, but mayapply energy to smaller regions of the arms. In some examples the apparatus may limit the application of energy to just regions contacting tissue.

[0110] In general, by modulating which electrodes energy is being applied to, these apparatuses may better match the impedance of the tissue. This impedance matching may also reduce the energy requirements. In addition, by applying energy to sub-regions as described, the arms may not need to be repositioned, but may be activated for different portions of the tissue between the arms (parallel or scissoring) at different times in order to treat the whole area. This technique may be particularly helpful for treating with submicrosecond or microsecond pulsing, in which impedance matching may be useful, as opposed to the use of radio frequency (RF) energy, in which impedance may be less critical. In general, setting or selecting the electrical properties (e.g., impedance) of the applied energy based on the electrical properties of the tissue between particular pairs of electrodes may allow the apparatus to deliver a more controlled amount of energy, e.g., at a lower power.[OHl] FIGS. 7-9 illustrate methods of treating tissue, including either (or both) adjusting the energy applied along the length of the arms (e.g., jaws) based on arm angle and / or applying energy between subsets of the electrodes to limit the instantaneous energy requirements. For example, in FIG. 7 the method shown may be used with tissue positioned between the first and second arms (701), so that the first and second arms close or clamp onto the tissue. The relative position (e.g., angle) between the arms / jaws may be determined (703), e.g., when tissue is positioned between the arms. Energy may be applied between pairs of the electrodes, and the energy applied may be determined and controlled as a function of the configuration of the applicator, such as the relative positions of the arms (e.g., arm angle) and / or the position of the electrode pairs along the proximal-to-distal length of the arms (705). This may allow the maintenance of a consistent (e.g., constant or near-constant) field strength, ablation pattern, etc. through the tissue between the arms, e.g., in a line or plane that extends between the arms (707).

[0112] In general, sensing the configuration of the applicator, such as the arm angle, may be used to determine the spacing between electrodes along the angled (e.g., scissoring) arms. For example, the controller may use the sensed angle information to calculate the distance between pairs of electrodes, based on the position of the electrode(s) on the arms. Thus, electrodes nearer to the distal end may be farther apart as the arms are opened, and a constant electric field may be maintained over the length of the arm by adjusting the applied energy to drive the most distal electrode pair at the highest energy, with electrodes closer to the vertexof the arms driven at lower and lower energies. The apparatus may be configured to set the field strength for tissue centered between the electrode pairs at approximately equal.

[0113] FIG. 8 schematically illustrates a method of applying energy between a pair of arms (e.g., jaws), and in particular, between a pair of long arms, by dividing the plurality of electrode pairs into subsets of electrode pairs and applying the energy sequentially to the different subsets of electrodes pairs. As discussed above, this may reduce the energy requirement and may allow for better matching of the impedance when applying, for example, nanosecond pulses of energy. For example, in FIG. 8 the tissue may first be positioned between the arms so that the tissue is between the first arm and the second arm (801). Either one or both the first arm and the second arm may include a plurality of electrodes forming electrode pairs. The plurality of electrode pairs may be divided up into a plurality of subsets of electrode pairs. In some examples the electrode pairs may be within predetermined subsets, divided up along the proximal -to-distal length of the arms (803). Thus the step of dividing up the plurality of electrodes (e.g., electrode pairs) into a plurality of electrodes may refer to accessing a predetermined grouping of sets / subsets of electrode pairs.

[0114] The method shown in FIG. 8 may then apply energy to each subset or some subsets of the plurality of subsets separately at different times, without repositioning the tissue or the arms (805). Energy may be applied sequentially to different subsets of the electrodes (e.g., subsets of electrode pairs) as mentioned above. The different subsets of electrodes may be driven to apply the sub-microsecond pulsing in turn along the length of the arms (e.g., proximal -to-distal or distal-to-proximal), or may be driven in a pattern of non- adjacent sub-sets. The number of electrodes within each subset may be, e.g., 1 pair of electrodes, 2 pair of electrodes, 3 pair of electrodes, 4 pair of electrodes, 5 pair of electrodes, etc. The multiple subsets may be activated with little or no delay between the activation of different subsets.

[0115] Each subset of electrodes may be powered for a sufficient time to treat the tissue. Thus, the total treatment time may be increased using this technique, but the total energy requirement may be much less.

[0116] FIG. 9 illustrates an example of a method of treating tissue similar to that shown in FIG. 8, in which one or more subsets of electrodes (e.g., pairs of electrodes) are excluded from the application of the electric pulses, e.g., sub -microsecond pulses. One or more subsets of electrodes may be excluded from the application of electric field for various reasons, for example, based on being identified as not contacting tissue. As described in more detail below, the plurality of subsets of electrode pairs may be divided into electrodes contactingtissue and electrodes that do not contact the tissue, and the energy may be applied only to those electrode pairs (e.g., those subsets of electrode pairs) that contact the tissue.

[0117] In FIG. 9 the method may include starting the treatment once the tissue is positioned between the first and second arms. Optionally, the method may include positioning the tissue between the first arm and second arm (901). The method may include determining which electrodes (or pairs of electrodes) are contacting the tissue (903). Electrodes contacting the tissue may be grouped together as a single subset or may be divided up into sub-sets having a plurality of different electrodes. Contact may be determined as described above. For example, one or more sensors may be used, including optical sensors, mechanical sensors (e.g., pressure sensors) and / or electrical sensors. In some examples, the electrodes may be used as sensors, either active electrical sensors that may apply energy and measure a response (such as resistance, impedance, capacitance, or inductance) or as passive sensors that may record electrical activity from the tissue (e.g., for cardiac tissue, electrocardiographic signals). One or more subsets of electrodes that are contacting the tissue may be determined. In some examples the group of electrodes that are identified as contacting the tissue may be divided up into relatively small size sub-sets, which may be arranged by location along the proximal-to-distal length of the arms (e.g., arms). For example, subsets may be limited to two or fewer pairs of electrodes (3 or fewer, 4 or fewer, etc.).

[0118] Once the plurality of electrodes has been divided into subsets, energy may be applied to the subset(s) of electrodes that are contacting the tissue (905). If multiple subsets of electrodes are contacting the tissue, energy may be applied to the different subsets sequentially, as described above, or simultaneously. Energy may be applied to the electrodes that are in contact with the tissue and no energy, or a lower level of energy, may be applied to electrodes that are not in contact (or not fully in contact) with tissue. In some examples it may be beneficial to apply at least some energy between electrodes that are not in contact with tissue (or not fully in contact with tissue), at a lower (e.g., non-zero) level. The lower level may be, e.g., a percentage of the energy applied to the contacting electrodes (e.g., 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50%, etc.).

[0119] The apparatuses described herein may include arms (or jaws) that are bent or curved. For example, FIGS. 10A-10B illustrate an example of an applicator having two curved arms, a first arm 1003 and a second arm 1005. Tissue may be held securely between the arms, as described above. In FIGS. 10A-10B the arms each include a plurality of electrodes. For example, in FIG. 10A the first arm includes three electrodes 1033, 1034, 1035, and the second arm includes two electrodes 1031, 1032. Each arm may have anynumber of electrodes, and the number of electrodes on each arm may be the same or different from each other. In this example, the arms may also open / close in a scissoring manner, by pivoting about the pivot point (e.g., fulcrum 1037). In FIGS. 10A and 10B the electrodes may also follow the curvature of the arms to which they are attached. The apparatus may also include one or more position sensor configured to sense the relative position between the first arm and the second arm. In this example, the power controller may determine the relative positions of the electrodes based on the determined sensed positions, as described above.

[0120] In general, the apparatuses and methods described herein may include multiple pivoting or moving regions and one or more position sensors may determine the configuration or position of the arms, and therefore the one or more electrodes on the arms. For example, FIG. 11 illustrates an example of a device 1101 having a fulcrum (pivot point) 1137 and arms with scissoring portions as well as pivoting portions of each arm. For example, the first arm includes a first portion 1103 and a second portion 1103’, and the second arm includes a first portion 1105 and a second portion 1105’. A plurality of electrodes may be present on one or both of the second (and / or optionally the first) arm portions. In this example, three position sensors (not shown) may determine the position of the first and second arms. For example, a first position sensor may determine the relative angle (e.g., 0i) between the first portion of the first arm 1103 and the second portion of the first arm 1103’. In this example, 0i is the angle between the first and second portions of the first arm. A second position sensor may determine the relative angle (e.g., 02) between the first portion of the second arm 1105 and the second portion of the first arm 1105’. A third position sensor may determine the relative angle (e.g., 0s) between the first portion of the first arm 1103 and the first portion of the second arm 1105. The controller may determine the relative positions (e.g., distances between) the electrodes forming the electrode pairs based on these three angles (0i, 02, and 0s). Alternatively, in some examples a single shape sensor (e.g., a fiber optic shape sensor, a magnetic shape sensor, etc.) may be used to determine the relative positions of the arms and / or electrodes. In the example device shown in FIG. 11, each arm (e.g., pivoting portion of each arm) can pivot independently based on contact with tissue 1121, so the first arm (and any associated electrodes) could be at an angle of 0i to the first cross-member (e.g., first portion of the first arm), and the second arm (and any associated electrodes) can be at 02 from the second cross-member (e.g., first portion of the second arm). By measuring 0i, 02, and 03, the system may determine the angle between the arms / electrodes and then adjust the energy between each electrode pair accordingly.Curved / Loop Applicators

[0121] As mentioned, also described herein are applicators having a curved or looping configuration in which the long, flexible (e.g., bendable) body of the applicator is configured to bend or curve and loop fully or partially around the tissue. Electrodes on the flexible body may be paired with each other to apply energy as described herein. In any of these examples the apparatus may include one or more position or shape sensors to determine the configuration of the region of the apparatus including the electrodes.

[0122] In particular, described herein are applicators that are configured to deliver pulsed electrical energy to a target tissue that form a loop that may be constricted onto the tissue (including the target tissue). These applicators may also be referred to herein as lasso applicators. FIGS. 12, 13A-13D and 14A-14C illustrate examples of applicators forming a loop (lasso applicators) that may be constricted around the tissue.

[0123] FIG. 12 shows an example of an applicator configured as a constrictable loop. In this example, the applicator 1201 includes a flexible elongate body 1205 and a plurality of electrodes 1281, 1281’ along a length of a first end region of the flexible elongate body. In FIG. 12, a plurality of tandem pairs of electrodes 1281, 1281’ is shown arranged down the length of at least a portion of the length (e.g., a first end region) of the apparatus. The pairs of electrodes in this example are arranged so that each member of the pair of electrodes are parallel to each other along the length of the first end region. Alternatively, in some examples (shown in FIGS. 13A-13D, and 14A-14C) the electrodes may be arranged as single line of electrodes along the length. In FIG. 12 the electrodes 1281 and 1281’are shown having relatively long and narrow, e.g., rectangular, shapes (e.g., outer surfaces). In some examples the electrodes may instead be shorter, and may have any appropriate shape (e.g., round, oval, square, etc.). The pairs of electrodes may be used to apply electrical energy therebetween. The electrodes may be arranged on one side of the applicator, and in particular, on the side configured to be within the loop formed, as shown.

[0124] The apparatus shown in FIG. 12 is configured as a lasso applicator, which includes a connector (e.g., a lasso connector or lasso channel) 1285, for example, at an end of the first end region having the electrodes. The lasso connector 1285 (e.g., lasso channel) may be configured to slidingly receive the opposite end of the flexible elongate body. Thus, the loop may be formed by sliding the first end along the length of the flexible elongate body, causing the loop to constrict. For example, the second end of the flexible elongate body may be inserted through the lasso connector so that the length of the first end region of the flexible elongate body forms a loop. In any of these apparatuses, different sections (corresponding todifferent pairs of electrodes) could be used to apply energy independently to prevent the impedance from being too low.

[0125] FIG. 13A shows an example of a loop applicator (e.g., lasso applicator 1301) similar to that shown in FIG. 12, in a first, linear configuration. The apparatus has a first end 1391 and a second end 1390. A plurality of electrodes 1381 are arranged along a length of the first end region. The first end of the apparatus may include a lasso connector 1385 (e.g., lasso channel), as described above, having an inner diameter that is configured to receive the opposite end (e.g., the second end 1390) to form a loop. The connector (e.g., lasso connector / lasso channel) 1385 may be a T-shaped or Y-shaped connector that is securely coupled to the first end 1391 of the applicator. The channel may have an inner diameter that is the same size as or slightly larger than the outer diameter of the elongate body, so that the elongate body may slide within the lasso connector. In some cases the channel may be relatively short and may have a diameter that is approximately the same as or smaller than the diameter of the elongate body (e.g., forming an aperture). Alternatively, the channel may be longer than the diameter of the elongate body, as shown in FIGS. 12 and 13A-13D. The inner lumen of the channel may be lubricious and / or may include a sensor (e.g., encoder, magnetic sensor, optical sensor, etc.) configured to determine how large the loop formed by the device is and / or the configuration of the loop region. In some cases the sensor may identify one or more markings on the elongate flexible body that indicate the “depth” and therefore the size of the loop.

[0126] In FIG. 13 A, a plurality of electrical connector contacts 1387 are shown at the second end region (e.g., adjacent to the second end 1390) of the apparatus. The elongate body of the device is flexible. The flexibility may vary along the length, or it may be approximately the same. In some examples the second end may be more flexible than the first end. The electrical connectors (e.g., electrical connector contacts 1387) may couple to each of the electrodes 1381 individually or collectively, as described above. For example, each connector may uniquely be in electrical communication with one of the electrodes 1381. In some examples, pairs of electrodes may be determined based on the dimension of the loop, for example, so that electrodes that are opposite from each other may be paired to apply energy across the tissue held within the loop. In some examples adjacent pairs of electrodes along the length may be paired.

[0127] As mentioned, the loop-forming apparatus may also include one or more sensors (e.g., shape sensors) for determining the shape (e.g., size, such as diameter or radius) of the loop formed. Any of these apparatuses may also include an energy controller configured to determine, based on the sensed data, which pairs of electrodes in the loop to apply energy toin order to achieve a desired treatment (e.g., ablation) and / or field strength, such as, but not limited to, a more uniform field strength and / or ablation pattern.

[0128] FIGS. 13B-13D illustrate one example of a method of operating a loop-forming (lasso) applicator apparatus. In this example, the second end 1390 (e.g., the end opposite from the end having the lasso connector 1385) is first inserted into the tissue so that it may be passed around a tissue 1393 in a direction 1394. The tissue may be or may contain the target tissue. This is illustrated in FIG. 13B. This second end 1390 may then be passed back out of the tissue (as shown by direction 1394 in FIG. 13C), preferably along the same path that it took to access the target tissue. Either once outside of the tissue or while still within the tissue, the second end may be threaded through the inner lumen of the lasso connector, as shown in FIG 13D. The loop 1370 formed may then be constricted down on the target, e.g., by pulling 1377 the second end away from the tissue, reducing the diameter of the loop 1370. In this manner, the loop may be constricted around the tissue 1393.

[0129] Once in place, the apparatus may be used to apply energy to the tissue. For example, energy may be applied between two or more electrodes within the loop to treat the tissue. Electrodes that are not in contact with the tissue (or target tissue) or that are not within the loop may not be used, as described above. For example, the energy controller may receive readings from the one or more sensors and determine which electrodes are not within the loop and / or within contact with the tissue.

[0130] Any of the apparatuses described herein may also or alternatively include a leash 1395, as shown in FIGS. 13B-13D that may be coupled to the first end of the applicator. The leash may be used to remove (e.g., loosen, open, etc.) the loop after it has been used. For example, pulling on the leash 1395 may cause the first end to slide towards the second end of the apparatus, opening the loop, until the second end can be withdrawn from the lasso connector and the applicator can be removed from the body.

[0131] In general, the methods and apparatuses using an apparatus including a lasso-type applicator may be used in any appropriate tissue. For example, lasso-type applicators may be used to treat cardiac tissue. In some examples the tissue may be treated as shown in FIGS. 13A-13D so that the lasso (loop) is placed around all the pulmonary veins (all four of the pulmonary veins or a subset thereof).

[0132] For example, the lasso-type applicator may be used to treat atrial fibrillation. For example, the apparatus may be inserted around one or more pulmonary veins by inserting a first length of a flexible elongate body around one or more pulmonary veins, e.g., the first end of the flexible elongate body, which may be steerable and / or may follow over a guide device, such as a guidewire. In some cases the first end of the flexible elongate body may couple to aguidewire, e.g., via a channel or rapid-exchange connection. Once threaded into and around the tissue, the first end may be passed back out of the tissue (e.g., along the same pathway, to prevent capturing non-target tissue within the loop to be formed). The first end of the flexible elongate body may then be inserted into a lasso connector at a second end of the flexible elongate body to form a loop. The loop may then be constricted around the target tissue (e.g., one or more pulmonary veins). The first end (or first end region) may be coupled to a controller and / or power supply to apply energy from the second end region forming the loop. Energy may be applied between two or more electrodes within the loop, e.g., to treat atrial fibrillation. Sensing may be used to confirm placement and / or treatment. For example, the same electrodes used to treat may be used to sense, and / or separate sensing electrodes may be used. Alternatively, a separate device may be used to sense. Once the energy has been applied, which may be performed in multiple steps or stages, e.g., between different sets of electrodes), the loop may be removed. For example, the first end may be pulled, e.g., by pulling on a leash connected to the second end or second end region (in some cases connected to the lasso connector / lasso channel) to open the loop up until the first end is removed from the lasso connector. In some cases inserting the first length includes forming the loop and constricting the loop around all four pulmonary veins.

[0133] As described above, any of these methods, including the methods using a lassotype applicator, may include adjusting the applied energy based on the separation between the electrodes of an electrode pair. In the context of the lasso applicators, a controller may be used to estimate the distance based on the known spacing of the electrodes along the length of the arm forming the lasso, and the radius / diameter or chord of the loop between the electrodes, which may be estimated from the length and / or the angle of curvature of loop. Thus, the controller may adjust the applied energy based on this distance and / or on the type of tissue between the electrodes, which may be estimated from the electrical properties (e.g., fat / not fat tissue, etc.) as described above.

[0134] The methods of using the lasso-type applicator may also include determining a spacing between a first electrode and a second electrode of a lasso-type applicator (that forms a constrictable loop, e.g., having a variable loop diameter), wherein the first and the second electrodes are spaced apart from each other on the loop that at least partially surrounds a tissue of a subject. The method may include determining the spacing by estimating a diameter or chord distance between the electrodes based on the length of the loop, which may be determined by one or more sensors. The sensors may sense the length of the loop and / or the curvature of the loop. Thus the controller may calculate the diameter / chord distance based on the length of the loop and / or curvature of the loop. The method may further include applyingenergy between the pairs of electrodes on the arm forming the loop, wherein the applied energy may be adjusted for each pair of electrodes based on the distance between the electrodes.

[0135] FIGS. 14A-14C show alternative views of another example of a loop-forming applicator 1401 similar to that shown in FIGS. 13A-13D. In this example, the apparatus includes a flexible elongate body with the second end (not visible) threaded through the lasso connector 1485 to form a loop 1470 that may be positioned around a target tissue. A plurality of electrodes 1481 are arranged around the inner diameter of the loop.

[0136] Any of the apparatuses described herein may include software (e.g., programs) for performing any of the methods described in FIGS. 7-9. For example, these apparatuses may include non-transitory computer-readable storage medium storing a set of instructions capable of being executed by a processor (e.g., a controller, such as the energy controller) to perform any of these methods, including the methods described above for FIGS. 7-9.

[0137] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. Furthermore, it should be appreciated that all combinations of the concepts of the present disclosure (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the benefits described herein.

[0138] Any of the methods (including user interfaces) described herein may be implemented as software, hardware or firmware, and may be described as a non-transitory computer-readable storage medium storing a set of instructions capable of being executed by a processor (e.g., computer, tablet, smartphone, etc.), that when executed by the processor causes the processor to control perform any of the steps, including but not limited to: displaying, communicating with the user, analyzing, modifying parameters (including timing, frequency, intensity, etc.), determining, alerting, or the like. For example, any of the methods described herein may be performed, at least in part, by an apparatus including one or more processors having a memory storing a non-transitory computer-readable storage medium storing a set of instructions for the processes(s) of the method.

[0139] While various embodiments have been described and / or illustrated herein in the context of fully functional computing systems, one or more of these example embodiments may be distributed as a program product in a variety of forms, regardless of the particular type of computer-readable media used to actually carry out the distribution. The embodiments disclosed herein may also be implemented using software modules that performcertain tasks. These software modules may include script, batch, or other executable files that may be stored on a computer-readable storage medium or in a computing system. In some embodiments, these software modules may configure a computing system to perform one or more of the example embodiments disclosed herein.

[0140] As described herein, the computing devices and systems described and / or illustrated herein broadly represent any type or form of computing device or system capable of executing computer-readable instructions, such as those contained within the modules described herein. In their most basic configuration, these computing device(s) may each comprise at least one memory device and at least one physical processor.

[0141] The term “memory” or “memory device,” as used herein, generally represents any type or form of volatile or non-volatile storage device or medium capable of storing data and / or computer-readable instructions. In one example, a memory device may store, load, and / or maintain one or more of the modules described herein. Examples of memory devices comprise, without limitation, Random Access Memory (RAM), Read Only Memory (ROM), flash memory, Hard Disk Drives (HDDs), Solid-State Drives (SSDs), optical disk drives, caches, variations or combinations of one or more of the same, or any other suitable storage memory.

[0142] As used herein, a processor may include hardware that runs the computer program code. Specifically, the term ‘processor’ may include a controller and may encompass not only computers having different architectures such as single / multi-processor architectures and sequential (Von Neumann) / parallel architectures but also specialized circuits such as field- programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other devices. In addition, the term “processor” or “physical processor,” as used herein, generally refers to any type or form of hardware-implemented processing unit capable of interpreting and / or executing computer-readable instructions. In one example, a physical processor may access and / or modify one or more modules stored in the above-described memory device. Examples of physical processors comprise, without limitation, microprocessors, microcontrollers, Central Processing Units (CPUs), Field-Programmable Gate Arrays (FPGAs) that implement softcore processors, Application-Specific Integrated Circuits (ASICs), portions of one or more of the same, variations or combinations of one or more of the same, or any other suitable physical processor.

[0143] Although illustrated as separate elements, the method steps described and / or illustrated herein may represent portions of a single application. In addition, in some embodiments one or more of these steps may represent or correspond to one or more softwareapplications or programs that, when executed by a computing device, may cause the computing device to perform one or more tasks, such as the method step.

[0144] In addition, one or more of the devices described herein may transform data, physical devices, and / or representations of physical devices from one form to another. Additionally or alternatively, one or more of the modules recited herein may transform a processor, volatile memory, non-volatile memory, and / or any other portion of a physical computing device from one form of computing device to another form of computing device by executing on the computing device, storing data on the computing device, and / or otherwise interacting with the computing device.

[0145] The term “computer-readable medium,” as used herein, generally refers to any form of device, carrier, or medium capable of storing or carrying computer-readable instructions. Examples of computer-readable media comprise, without limitation, transmission-type media, such as carrier waves, and non-transitory-type media, such as magnetic-storage media (e.g., hard disk drives, tape drives, and floppy disks), optical-storage media (e.g., Compact Disks (CDs), Digital Video Disks (DVDs), and BLU-RAY disks), electronic-storage media (e.g., solid-state drives and flash media), and other distribution systems.

[0146] A person of ordinary skill in the art will recognize that any process or method disclosed herein can be modified in many ways. The process parameters and sequence of the steps described and / or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and / or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed.

[0147] The various exemplary methods described and / or illustrated herein may also omit one or more of the steps described or illustrated herein or comprise additional steps in addition to those disclosed. Further, a step of any method as disclosed herein can be combined with any one or more steps of any other method as disclosed herein.

[0148] The processor as described herein can be configured to perform one or more steps of any method disclosed herein. Alternatively or in combination, the processor can be configured to combine one or more steps of one or more methods as disclosed herein.

[0149] When a feature or element is herein referred to as being "on" another feature or element, it can be directly on the other feature or element or intervening features and / or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being "connected","attached" or "coupled" to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected", "directly attached" or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.

[0150] Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ".

[0151] Spatially relative terms, such as "under", "below", "lower", "over", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as "under”, or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly", "downwardly", "vertical", "horizontal" and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

[0152] Although the terms “first” and “second” may be used herein to describe various features / elements (including steps), these features / elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature / element from another feature / element. Thus, a first feature / element discussed below could be termed a second feature / element, and similarly, a second feature / element discussedbelow could be termed a first feature / element without departing from the teachings of the present invention.

[0153] In general, any of the apparatuses and methods described herein should be understood to be inclusive, but all or a sub-set of the components and / or steps may alternatively be exclusive and may be expressed as “consisting of’ or alternatively “consisting essentially of’ the various components, steps, sub-components or sub-steps.

[0154] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word "about" or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and / or position to indicate that the value and / or position described is within a reasonable expected range of values and / or positions. For example, a numeric value may have a value that is + / - 0.1% of the stated value (or range of values), + / - 1% of the stated value (or range of values), + / - 2% of the stated value (or range of values), + / - 5% of the stated value (or range of values), + / - 10% of the stated value (or range of values), etc. Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value " 10" is disclosed, then "about 10" is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also understood that when a value is disclosed that "less than or equal to" the value, "greater than or equal to the value" and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value "X" is disclosed the "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a numerical value) is also disclosed. It is also understood that throughout the application, data is provided in a number of different formats, and that this data represents endpoints and starting points, and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0155] Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, theforegoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.

[0156] The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

Claims

CLAIMSWhat is claimed is:

1. An applicator apparatus for delivering pulsed electrical energy, the apparatus comprising: a first arm having a proximal end and a distal end; a second arm having a proximal end and a distal end; a plurality of electrodes positioned along at least a portion of a length of the first arm; an arm actuator configured to adjust a separation between the first arm and the second arm; a position sensor configured to sense a relative position between the first arm and the second arm; and a controller receiving input from the position sensor and configured to adjust the energy applied to the plurality of electrodes based on the relative position between the first arm and the second arm.

2. The apparatus of claim 1, wherein the arm actuator is configured to adjust the separation between the first arm and the second arm by adjusting an angle between the first arm and the second arm.

3. The apparatus of claim 1, wherein the controller is configured to adjust the energy applied to the plurality of electrodes positioned along the length of the first arm based on the relative position between the first arm and the second arm so that the applied energy results in a consistent field strength or in a consistent region of ablation within a tissue between the first arm and the second arm at least along a portion of a distal to proximal line extending between the first and second arms.

4. The apparatus of claim 1, wherein the controller is configured to maintain a relatively consistent electrical field between the first and second arms and / or maintain a relatively consistent region of ablation through a tissue held between the first and second arms by adjusting one or more of: pulse width, pulse amplitude, number of pulses.

5. The apparatus of any of claims 1-4, wherein the controller is further configured to detect a subset of the plurality of electrodes that are in contact with a tissue and toreduce or prevent the application of power to electrodes that are not in contact with the tissue.

6. The apparatus of claim 5, wherein the controller is configured to detect the subset of the plurality of electrodes based on impedance values for electrodes of the plurality of electrodes.

7. The apparatus of any of claims 1-6, further comprising a second plurality of electrodes positioned along a length of the second arm.

8. The apparatus of claim 7, wherein the controller is configured to adjust the energy applied between pairs of electrodes from the plurality of electrodes positioned along the length of the first arm and the second plurality of electrodes positioned along the length of the second arm that are opposite each other, based on the relative position between the first arm and the second arm.

9. The apparatus of claim 1, wherein the second arm comprises one or more electrodes, the apparatus comprises a multiplexer, and the controller is configured to control multiplexer to determine which electrodes on the first and / or second arm to pair and to apply energy between.

10. The apparatus of any of claims 1-9, wherein the arm actuator comprises a handle.

11. The apparatus of any of claims 1-10, further comprising a pulse generator coupled to the controller, wherein the pulse generator comprises a high voltage pulse generator.

12. The apparatus of any of claims 1-11, wherein the first arm and second arm are curved.

13. The apparatus of any of claims 1-12, wherein the position sensor comprises one or more of: an angle sensor, a magnetic angle sensor, a capacitive sensor, a photoelectric sensor, an eddy current sensor, or a position encoder.

14. The apparatus of any of claims 1-13, wherein the first arm and the second arm are configured to open in a scissoring manner and / or pivot relative to each other.

15. The apparatus of any of claims 1 and 3-13, wherein the first arm and the second arm are configured to open and close in parallel.

16. The apparatus of any of claims 1-15, wherein the plurality of electrodes positioned along the length of the first arm alternate in polarity.

17. The apparatus of any of claims 1-6, further comprising one or more electrodes on the second arm, wherein the electrodes on the first arm are opposite polarity from the one or more electrodes on the second arm.

18. The apparatus of any of claims 1-6, further comprising one or more electrodes on the second arm, wherein the electrodes on both the first and the second arm are of alternating polarity.

19. An applicator apparatus for delivering pulsed electrical energy, the apparatus comprising: a first arm having a proximal end and a distal end; a second arm having a proximal end and a distal end; a first plurality of electrodes positioned along at least a portion of a length of the first arm between the proximal end and the distal end; a second plurality of electrodes positioned along at least a portion of a length of the second arm between the proximal end and the distal end; an arm actuator configured to adjust a relative position between the first arm and the second arm; a position sensor configured to sense an angle between the first arm and the second arm; and an energy controller receiving input from the position sensor and configured to adjust energy applied between individual pairs of electrodes from the first plurality of electrodes and the second plurality of electrodes based on the angle between the first arm and the second arm to apply a consistent field strength between the first arm and the second arm along at least a portion of a distal to proximal line extending between the first and second arms.

20. A method, the method comprising: determining a relative position or an angle between a first arm and a second arm of an applicator, wherein the first and the second arms are clamped on a tissue of a subject; and applying energy between pairs of electrodes positioned on the first arm and / or the second arm, wherein the applied energy is adjusted for each pair of electrodesbased on the relative position or the angle between the first arm and the second arm.

21. The method of claim 20, comprising adjusting the applied energy to result in a consistent field strength or a consistent region of ablation of the tissue between the first arm and the second arm along at least a portion of a distal to proximal line extending between the first and second arms.

22. The method of claims 20 or 21, comprising selecting an electrode pair from non- adjacent electrodes to adjust a depth of penetration of the applied energy.

23. The method of claim 20 or 21, wherein the energy is adjusted so that the electrode pairs closer to a vertex region between the first arm and the second arm have a lower applied voltage and / or lower applied pulse number than electrode pairs further from the vertex region.

24. The method of any of claims 20-23, wherein applying energy comprises applying sub-microsecond electrical pulses having an amplitude of at least 0.1 kV.

25. The method of any of claims 20 -24, further comprising determining which electrodes on the first arm and / or the second arm are in contact with the tissue.

26. The method of claim 25, wherein applying energy between pairs of electrodes comprises applying energy between only pairs of electrodes in contact with the tissue.

27. The method of any of claims 20-26, wherein positioning the tissue comprises positioning a cardiac tissue between the first and second arms.

28. The method of any of claims 20-27, wherein positioning the tissue comprises closing the first and second arms against the tissue in a scissoring manner.

29. An applicator apparatus for delivering pulsed electrical energy, the apparatus comprising: a first arm having a proximal end and a distal end; a second arm having a proximal end and a distal end; a first plurality of electrodes positioned along at least a portion of a length of the first arm between the proximal end and the distal end; anda controller configured to apply energy to the plurality of electrodes, wherein the controller is further configured to detect a subset of the plurality of electrodes that are in contact with a tissue, and to limit the applied energy to the subset.

30. The apparatus of claim 29, wherein the controller is configured to detect the subset of the first plurality of electrodes based on impedance values for electrodes of the first plurality of electrodes.

31. The apparatus of claims 29 or 30, further comprising a second plurality of electrodes positioned along at least a portion of a length of the second arm from the proximal end to the second end.

32. The apparatus of claim 31, wherein the first plurality of electrodes is opposite polarity from the second plurality of electrodes.

33. The apparatus of any of claims 29-32, wherein the first arm and the second arm are configured to pivot relative to each other, open and close in parallel or open and close in a scissoring manner.

34. The apparatus of claim 30, wherein the impedance values indicate a type of tissue between the electrodes of the subset.

35. The apparatus of any of claims 29-33, further comprising a pulse generator coupled to the energy controller, wherein the pulse generator comprises a sub-microsecond, high voltage pulse generator.

36. The apparatus of any of claims 29-34, wherein the first arm and second arm are curved.

37. The apparatus of any of claims 29-35, wherein the first arm and the second arm are 5 cm or longer.

38. The apparatus of claim 29, wherein the plurality of electrodes positioned along at least the portion of the length of the first arm alternate in polarity.

39. An applicator apparatus for delivering pulsed electrical energy, the apparatus comprising: a first arm having a proximal end and a distal end; a second arm having a proximal end and a distal end;a plurality of electrodes positioned along at least a portion of a length of the first arm between the proximal end and the distal end; and an energy controller configured to sequentially apply energy to a plurality of subsets of the plurality of electrodes, so that high field- strength electric pulses are applied at different regions along the length of the first arm at different times.

40. The apparatus of claim 39, wherein the energy controller is configured to determine a subset of the plurality of electrodes to match impedance of electrodes in the subset to match impedance of a pulse generator generating electric pulses to be delivered by the electrodes in the subset.

41. The apparatus of claims 39 or 40, wherein the energy controller is configured to activate the different regions along the length of the first arm without repositioning the first and second arms, or a target tissue.

42. The apparatus of claim 39, further comprising a pulse generator coupled to the energy controller, wherein the pulse generator comprises a microsecond or a submicrosecond, high voltage pulse generator.

43. The apparatus of any of claims 39- 42, wherein the first arm and the second arm are 5 cm or longer.

44. An applicator apparatus for delivering pulsed electrical energy to a target tissue, the apparatus comprising: a flexible elongate body; a plurality of electrodes along a length of a first end region of the flexible elongate body; and a lasso connector at an end of the first end region configured to slidingly receive a second end of the flexible elongate body, wherein the second end of the flexible elongate body is configured to be inserted through the lasso connector so that at least a portion of the length of the first end region of the flexible elongate body forms a loop.

45. The apparatus of claim 44, further comprising a plurality of electrical connectors at a second end region of the flexible elongate body, wherein the plurality of electrical connectors are in electrical communication with the plurality of electrodes.

46. The apparatus of claims 44 or 45, wherein the loop may be constricted by pulling the second end region through the lasso connector.

47. The apparatus of any of claims 44-46, wherein the plurality of electrodes are positioned within an inner surface of the loop.

48. The apparatus of any of claims 44-47, wherein the plurality of electrodes comprise a plurality of pairs of electrodes that are arranged so that members of the pair of electrodes are parallel to each other along the length of the first end region.

49. The apparatus of any of claims 44-48, further comprising a leash coupled to the first end region and / or the lasso connector to open the loop.

50. A method, the method comprising: inserting a first length of a flexible elongate body around a tissue; inserting a first end of the first length of the flexible elongate body into a lasso connector at a second end of the flexible elongate body to form a loop; constricting the loop around the tissue; and applying energy between two or more electrodes within the loop to treat the tissue.

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