Abstract:
The present disclosure relates to the field of tissue mapping and ablation. Specifically, the present disclosure relates to expandable medical devices for identifying and treating local anatomical abnormalities within a body lumen. More specifically, the present disclosure relates to systems and methods of focal treatment for overactive bladders.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application Ser. No. 62/200,326, filed on Aug. 3, 2015, the entire disclosure of which is herein incorporated by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to the field of tissue mapping and ablation. In particular, the present disclosure relates to devices and methods for proper positioning of mapping and ablation electrodes within body lumens, including the bladder. 
       BACKGROUND 
       [0003]    Overactive bladder is a medical condition that affects more than 50 million people in the United States. Individuals with an overactive bladder typically experience an increase in urge and frequency of urination, and occasionally incontinence. An overactive bladder may result from increased triggering of the sensory pathways involved in normal bladder control. It has been suggested that abnormal bladder activity may result from morphological changes in one or more distinct anatomical areas of the bladder, including the dome, internal sphincter or trigone. For example, localized changes in detrusor muscle morphology resulting from defects at the cellular and multicellular level tend to correlate with pathological changes, e.g., patchy denervation due to increased amounts of connective tissue between muscle bundles, which may contribute to abnormal muscle function on a macroscopic level. These localized defects often manifest as elevated electrical activity within specific tissue regions of the bladder wall. Identifying and treating these localized defects may prevent or eliminate the symptoms of overactive bladder. Current treatments for overactive bladder, such as systemic administration of drugs, nerve stimulation or Botox injections, are applied to the entire bladder rather than specifically targeting local anatomical abnormalities. Because the therapeutic effect eventually wears off, these treatments often need to be repeated multiple times. Unfortunately, overtreatment may lead to urinary retention that requires self-catheterization to void the bladder. 
         [0004]    The transient nature of these systemic treatments may be addressed by mapping the tissues of the bladder wall to identify where local bladder abnormalities originate and then specifically targeting therapeutic treatment to those areas. Currently available bladder mapping devices do not conform to the shape of the bladder and cannot reliably establish and/or maintain contact between each of the electrodes and the bladder wall. Proper positioning of the electrodes may be achieved by, for example, placing the electrodes on an expandable framework or attaching the electrodes to the surface of a balloon, as described by Drake et al. (BJU International 2005, vol. 95, pp. 1002-1005). Due to the asymmetric nature of the bladder, it is important that the device be properly oriented prior to expansion. However, conventional catheters simply deliver these devices into the central lumen of the bladder regardless of the specific internal dimensions. This often prevents the mapping and ablation electrodes from contacting a significant portion of the bladder wall. 
         [0005]    There is a continued need for mapping and ablation systems that conform to the shape of an individual&#39;s bladder, along with a steerable delivery system that allows for precise orientation prior to deployment. 
       SUMMARY 
       [0006]    Particular embodiments of the disclosure are described in the Summary and Detailed Description of the Preferred Embodiments, below. Although the disclosure has been described in connection with specific embodiments, it should be understood that the disclosure as claimed should not be unduly limited to such specific embodiments. 
         [0007]    The present disclosure relates generally to electrode-bearing mapping and ablation systems that provide enhanced electrical connection with the bladder wall. In one aspect, the present disclosure relates to a medical device, comprising a steerable catheter comprising a proximal end, a distal end and a lumen extending therebetween; an expandable-collapsible framework slidably disposed within the lumen of the steerable catheter; and a plurality of electrodes carried about a surface of the expandable-collapsible framework. The expandable-collapsible framework may be formed from a shape memory material that assumes a pre-determined shape when not disposed within the lumen of the steerable catheter. Each of the plurality electrodes may be configured to serve as a sensing electrode, mapping electrode, stimulating electrode and/or ablation electrode. Each of the plurality of electrodes may contact a wall of the body lumen when the framework is in an expanded configuration. The expandable-collapsible framework may substantially maintain its shape (on a geometrically similar basis) as it is pushed from the catheter and expands. The expandable-collapsible framework may curve relative to a longitudinal axis of the medical device when in an expanded state. The expandable-collapsible framework may comprise a plurality of longitudinal members formed from a shape memory material that assumes a curved shape. The flexibility of each longitudinal member may vary along its length. Each of the longitudinal members may be joined together at their distal ends. A plurality of cross-pieces may extend between each of the curved longitudinal members. In addition or alternatively, the expandable-collapsible framework may include an internal support to bias the longitudinal members outward. The internal support may include an additional expandable framework or an inflatable balloon. The expandable-collapsible framework may further include a plurality of conducting wires such that a first end of each conducting wire is electrically coupled to a different one of the plurality of electrodes and a second end of each conducting wire is optionally electrically coupled to an ablation energy source and/or an electrical activity processing system. The ablation energy source may include a radio frequency (RF) generator. The electrical activity processing system may be configured to measure intrinsic electrical activity. 
         [0008]    In another aspect, the present disclosure relates to a medical device, comprising: a catheter comprising a proximal end, a distal end and a lumen extending therebetween; a helically-biased wire comprising a proximal end and a distal end slidably disposed within the lumen of the steerable catheter; and a plurality of electrodes carried about a surface of the helically-biased wire. Each of the plurality electrodes may be configured to serve as a sensing electrode, mapping electrode, stimulating electrode and/or ablation electrode. The helically-biased wire may be formed from a shape memory material that assumes a pre-determined shape when not disposed within the lumen of the steerable catheter. A diameter of the helically-biased wire may increase from the distal end toward a center of the helically-biased wire and from the proximal end toward the center of the helically-biased wire. An elongate member may be disposed within the catheter such that a distal end of the elongate member is attached to the distal end of the helically-biased wire. Each of the plurality of electrodes may contact a wall of the body lumen when the helically-biased wire is in an expanded configuration. The medical device may further include a plurality of conducting wires, wherein a first end of each of the conducting wires is electrically coupled to a different one of the plurality of electrodes, and a second end of each of the conducting wires is electrically coupled to an ablation energy source and/or an electrical activity processing system. The ablation energy source may include a radio frequency (RF) generator. The electrical activity processing system may be configured to measure intrinsic electrical activity. 
         [0009]    In another aspect, the present disclosure relates to a method comprising: introducing a medical device into a body lumen, wherein the medical device includes a steerable catheter comprising: a proximal end, a distal end and a lumen extending therebetween; an expandable-collapsible framework slidably disposed within the lumen of the steerable catheter; and a plurality of electrodes carried about a surface of the expandable-collapsible framework; moving the framework to an expanded configuration such that the electrodes carried about the surface of the framework contact a tissue of the body lumen; measuring the electrical activity within the tissue of the body lumen in contact with each of the electrodes; identifying each electrode that detected an elevated electrical activity within the tissue of the body lumen; and applying electrical energy to each electrode that identified elevated electrical activity. The body lumen may include the lumen of a bladder. The electrical energy applied by each electrode may reduce the elevated electrical within the tissue of the body lumen, thereby reducing at least one symptom of an overactive bladder. 
         [0010]    In another aspect, the present disclosure relates to a method comprising: introducing a medical device into a body lumen, wherein the medical device includes a catheter comprising a proximal end, a distal end and a lumen extending therebetween; a helically-biased wire comprising a proximal end and a distal end slidably disposed within the lumen of the steerable catheter; and a plurality of electrodes carried about a surface of the helically-biased wire; moving at least a portion of the helically-biased wire beyond the distal end of the catheter such that the helically-biased wire expands and the electrodes carried about the surface of the helically-biased wire contact a tissue of the body lumen; measuring the electrical activity within the tissue of the body lumen in contact with each of the electrodes; identifying each electrode that detected an elevated electrical activity within the tissue of the body lumen; and 
         [0011]    applying electrical energy to each electrode that identified elevated electrical activity. The body lumen may include the lumen of a bladder. The electrical energy applied by each electrode may reduce the elevated electrical within the tissue of the body lumen, thereby reducing at least one symptom of an overactive bladder. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Non-limiting embodiments of the present disclosure are described by way of example with reference to the accompanying figures, which are schematic and not intended to be drawn to scale. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures: 
           [0013]      FIG. 1  is a schematic side view of a mapping and ablation system comprising an expandable-collapsible framework that includes a proximal end and a distal end, between which flexible splines extend in a circumferentially spaced relationship, according to an embodiment of the present disclosure. 
           [0014]      FIG. 2  is a schematic side view of the framework of  FIG. 1 , wherein adjacent splines are connected by one or more cross-pieces to form a lattice-like structure, according to another embodiment of the present disclosure. 
           [0015]      FIG. 3  is a schematic side view of a mapping and ablation system comprising an expandable-collapsible framework that is deployable from the lumen of a steerable catheter, according to another embodiment of the present disclosure. 
           [0016]      FIG. 4  is a schematic side view of a mapping and ablation system that includes a framework formed from a series of offset splines for deployment within an asymmetrically shaped body lumen, according to another embodiment of the present disclosure. 
           [0017]      FIG. 5A ,  FIG. 5B  and  FIG. 5C  depict the spherical shape of an expandable-collapsible framework as it exits the distal tip of the steerable catheter, according to another embodiment of the present disclosure. 
           [0018]      FIG. 6  is a schematic side view of an expandable-collapsible framework that includes a relatively rigid dome and semi-flexible splines, according to another embodiment of the present disclosure. 
           [0019]      FIG. 7A  and  FIG. 7B  provide a schematic side view of an expandable-collapsible framework that includes a central telescoping arm that may be rotated about its axis to force the splines of the framework to move into a twisted configuration, according to another embodiment of the present disclosure. 
           [0020]      FIG. 8A ,  FIG. 8B  and  FIG. 8C  each provide a schematic side view of a mapping and ablation system that includes a shape memory wire with a helical bias that is deployable from the lumen of a steerable catheter, according to another embodiment of the present disclosure. 
           [0021]      FIG. 9A  and  FIG. 9B  depict a plurality of retractable needle electrodes extending from a spline of the mapping and ablation system into the bladder wall, according to another embodiment of the present disclosure. 
           [0022]      FIG. 10A  and  FIG. 10B  depict alternative electrode configurations, according to additional embodiments of the present disclosure. 
           [0023]      FIG. 11A ,  FIG. 11B  and  FIG. 11C  depict a section of the expandable-collapsible framework that includes a series of openings through which a suction may be applied to secure the framework to the bladder wall, according to another embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    Before the present disclosure is described in further detail, it is to be understood that the disclosure is not limited to the particular embodiments described, as such may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting beyond the scope of the appended claims. Unless defined otherwise, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs. Finally, although embodiments of the present disclosure are described with specific reference to systems and methods for mapping and ablating overactive tissue(s) within the bladder, it should be appreciated that the present disclosure may be applicable to mapping and ablating a variety of organs, including, for example, the gastrointestinal (GI) tract, stomach (e.g., irritable bowel disease, cancer, obesity etc.), uterus (e.g., fibroids, uterine bleeding etc.), esophagus, heart and vascular system. 
         [0025]    As used herein, the term “distal” refers to the end farthest away from a medical professional when introducing a device into a patient, while the term “proximal” refers to the end closest to the medical professional when introducing a device into a patient. 
         [0026]    As used herein, “expandable” or “expanded” refers to an increase in diameter, as compared to the diameter in a “collapsible” or “collapsed” configuration. As used herein, “diameter” refers to the distance of a straight line extending between two points and does not necessarily indicate a particular shape. 
         [0027]    All of the devices and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the devices and methods of this disclosure have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations can be applied to the devices and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the disclosure. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the disclosure as defined by the appended claims. 
         [0028]      FIG. 1  provides a schematic side view of a medical device comprising a catheter  10  that includes a proximal end (not shown), distal end  12  and lumen  14  extending therebetween. An expandable-collapsible framework  20  is slidably disposed within the lumen  14  of the catheter  10 . The framework  20  includes a proximal end  24  and a distal end  22 , between which a plurality of flexible curved longitudinal members (i.e., flexible splines  23 ) extend in a circumferentially spaced relationship. In some embodiments, the splines  23  that form the framework may include regions of varying flexibility and/or stiffness such that the framework  20  conforms to bladders of various shapes and sizes when in the expanded configuration. As shown in  FIG. 2 , adjacent splines  23  may be connected by a series of cross-pieces (i.e., struts  25 ) to form a mesh- or basket-like structure with enhanced structural integrity that defines an interior space when in the expanded configuration. The splines  23  and struts  25  may be made, for example, from a resilient inert material, including metals and metal alloys such as platinum, tungsten, titanium, stainless steel, nickel and nickel-titanium alloys (e.g., nitinol), polymers such as acrylate-based polymers, polyurethane-based polymers, polynorbornene-based polymers, and polylactide-based polymers, and any combinations thereof. 
         [0029]    A plurality of unipolar or bipolar electrodes  40  may be connected equidistantly about the outer surface of the framework  20  to identify and ablate tissue regions of the bladder wall  6  that exhibit aberrant electrical activity. In one particular embodiment (e.g.,  FIG. 2 ), an electrode may be attached at the intersection of each spline and strut. Each electrode may be electrically coupled to an electrical activity processing system and an ablation energy source by a separate electrically conductive wire that extends along the inner or outer surface of the framework (not shown). In another embodiment, the electrodes may be electrically coupled to an electrical activity processing system and ablation energy source by one or more flexible circuits printed along the inner or outer surface of the splines and/or struts of the framework. In yet another embodiment, the flexible printed circuits may form the splines and/or struts of the framework. 
         [0030]    As best illustrated in  FIG. 3 , in some embodiments, the distal end  12  of the catheter  10  may include a steerable segment  16  comprising a flexible and/or bendable material. Examples of steerable catheters may be found, for example, in U.S. Pat. Nos. 5,656,030 and 6,837,867 and U.S. Patent Publication No. 20100010437, which are hereby incorporated by reference. The steerable segment  16  allows the framework  20  to be precisely positioned within the bladder  5  to ensure that the splines  23  are in direct apposition with the bladder wall  6 . For example, the framework  20  may be delivered into a symmetrically shaped (e.g., spherical) bladder by positioning the catheter such that the distal end points toward the top of the bladder wall. As the framework exits the catheter lumen  14 , it will expand in a substantially uniform manner to fill the bladder. If, however, the bladder is asymmetrically shaped, e.g., the bladder is offset to one side, the catheter  10  may be oriented (i.e., steered) such that the distal end  12  preferentially points toward the predominant portion of the bladder. The ability to steer the distal end  12  of the catheter  10  allows the user to deliver the framework  20  within an asymmetrically shaped bladder in a manner that provides improved apposition of the splines  23  against the bladder wall  6 . 
         [0031]    As illustrated in  FIG. 4 , the splines  23  of the framework  20  may also be preferentially offset to one side to accommodate deployment within an asymmetrically shaped lumen. In one embodiment, each of the splines  23  may be individually deployed and/or retracted through the catheter lumen  14  as necessary to ensure that each spline conforms to the specific dimensions of the bladder wall. In addition, or alternatively, the interior space of the framework may include an asymmetric expander (not shown) configured to preferentially push the framework in one direction. 
         [0032]    As will be understood by those of skill in the art, the shape memory material comprising the framework may form any number of three-dimensional expanded shapes. In one embodiment, the pre-determined expanded shape may begin to form as the framework exits the lumen of the catheter, without necessarily requiring complete deployment. For example, as illustrated in  FIGS. 5A-5C , a framework  20  that includes a substantially spherical expanded shape may assume that shape as it is being deployed, independent of how much of the framework remains within the catheter lumen  14 . This allows the framework to be deployed incrementally as dictated by the size and/or shape of the bladder to ensure that each spline conforms to the specific dimensions of the bladder wall. 
         [0033]    Referring to  FIG. 6 , the ability of the framework  20  to conform to the bladder may be further adjusted by varying the flexibility of the splines  23  depending on their location within the framework. For example, the portion of each spline comprising the curved dome  23   a  of the framework may be formed from a relatively rigid (i.e., stiff) shape memory material that resists deformation as it compresses against the bladder wall. The longitudinal portion of each spline  23   b  connected to the rigid dome may be formed from a shape memory material that is more flexible than the relatively rigid shape memory material, for example, a semi-flexible (i.e., pliable) shape memory material that can bend inward or bow outward according to the corresponding contour of the bladder wall. Once properly positioned, an expansion piece  27  located within a middle portion of framework  20  may be used to urge the longitudinal portion of each spline  23   b  outward against the bladder wall. The expansion piece may maintain the splines in their proper location and provide internal support to prevent the splines from collapsing. A telescoping element (not shown) may be connected to a center portion of the expansion piece  27 . The telescoping element may extend through the lumen of the catheter to advance and/or retract the expansion piece  27  within the framework as necessary to properly support the framework  20  and, once properly positioned, to lock the expansion piece in place. The telescoping element may be retracted distally to allow the framework to collapse for removal. An expandable balloon  28  (or balloons) may also be positioned within the framework  20 . The balloon may be inflated as necessary to urge the splines  23  outward against the bladder wall and maintain the framework in the desired expanded configuration. The balloon may then be deflated to allow the framework to collapse for removal. In the embodiment shown, the balloon  28  is provided proximate to the region where the splines taper into the catheter lumen  14 , but could also be provided anywhere within the framework. In the embodiment shown, the balloon  28  is of annular (donut) shape, but could also be provided in a number of other shapes including spheroidal (e.g., in the form of a sphere, oblate spheroid or prolate spheroid), among others. 
         [0034]    Referring to  FIGS. 7A-7B , the ability to adjust the splines  23  to conform to the bladder wall  6  may be further enhanced with a central telescoping arm  21  that extends through the lumen of the catheter and the center of the framework  20 . The distal end of each spline  23  is attached to the distal end of the telescoping arm  21  and the proximal end of each spline  23  is free-floating about a middle portion of the telescoping arm  21 . As shown in  FIG. 7A , each of the splines aligns with the axis of the central telescoping arm in a substantially linear configuration. As shown in  FIG. 7B , rotating the proximal end (not shown) of the central telescoping  21  arm exerts tension (i.e., torque) along the length of each spline  23 , forcing the splines into a twisted configuration  23   a  about the axis of the telescoping arm. The relative stiffness of each spline increases as it moves from the straight to twisted configuration  23   a,  thereby placing each spline in firm apposition with the bladder wall  6 . 
         [0035]    Referring to  FIGS. 8A-8C , the framework of  FIGS. 1-7  may be replaced with a wire  30  formed from a shape memory material that includes a helical bias. A plurality of electrodes may be disposed along the length of the wire. In one embodiment, the wire  30  may be formed from a plurality of separate wires, each of which is electrically connected to a different one of the plurality of electrodes. As best illustrated in  FIG. 8A , the wire may be formed as a tight spiral coil when disposed within the lumen  14  of the catheter  10 . As the wire exits the distal end  12  of the catheter at or near the top (i.e., dome) of the bladder  5 , the helical bias urges the unconstrained wire  30  into a series of coils that expand according to the shape of the bladder. In another embodiment (not shown), the wire may be formed as a tight spiral coil wrapped around a stylet (i.e., guidewire) slidably disposed within the lumen of the catheter. The stylet and wire may be advanced through the lumen of the catheter into the bladder. Once properly positioned within the bladder, the stylet may be withdrawn from the tight spiral coil. As above, the helical bias urges the unconstrained wire into a series of coils that expand according to the shape of the bladder. More or less of the wire may  30  be advanced through the lumen  14  of the catheter  10  depending of the size of the bladder. For example, only a portion of the wire  30  is required to fill the smaller bladder  5  of  FIG. 8A , while the entire wire  30  is required to fill the larger bladder  5  of  FIG. 8B . As shown in  FIG. 8C , the coils of the helically-biased wire  30  may be adjusted to conform to the bladder wall by a central telescoping arm  21  that extends through the lumen  14  of the catheter  10  and is connected to the distal end of the helically-biased wire  30 . In one embodiment, retracting the proximal end (not shown) of the central telescoping  21  arm longitudinally compresses and urges coils of the helically-biased wire  30  to move radially outward against the bladder wall. Alternatively, the proximal end of the central telescoping arm  21  may be rotated in the direction of the winding of the helically-biased wire  30  to partially “wind” the helically-biased wire  30  or, conversely, rotated in a direction counter to the direction of winding of the wire  30  to partially “unwind” the helically-biased wire  30 . This “unwinding” releases a portion of the tension on the helically-biased wire  30  such that the winding of the helically-biased wire  30  expands in diameter, placing the helically-biased wire  30  into contact with the bladder wall. 
         [0036]    The surface of the framework or helically-biased wires described herein may include a variety of electrodes configured to “self-position” within the creases of the bladder wall. For example, as shown in  FIG. 9A-9B , a plurality of needle-shaped electrodes  42  (i.e., tines) may be disposed about the outer surface of each spline  23  to anchor the splines to the bladder wall  6 . These tines may be linear or non-linear, for example, formed into the shape of a hook  44  to further secure each electrode to the bladder wall. The increased adhesion offered by these tines may reduce noise artifacts common to mapping procedures, thereby allowing more accurate and reliable mapping of the bladder wall and more accurate focal delivery of ablation energy. The tines may be retractable to allow the framework or helically-biased wire to be released from the bladder wall without causing tissue damage once the mapping and ablation procedure is completed. The tines may further include one or more channels (not shown) for selectively delivering therapeutic agents, including, by way of non-limiting example, Botox or a neurotoxin into the bladder wall. 
         [0037]    As shown in  FIG. 10A , the electrode tines may include a helical shape  46  that serves as a “cork-screw” to penetrate the bladder wall. As an alternative to actively penetrating the bladder wall, the end of each electrode may include a channel  48  through which negative pressure (i.e., suction) may be drawn to temporarily secure the electrode  40  to the bladder wall ( FIG. 10B ). Alternatively, as shown in  FIGS. 11A-11B , a section of each spline  23  may include a series of openings  49  through which negative pressure may be drawn, thereby placing the electrodes  40  adjacent to each opening  49  in contact with the bladder wall  6 . Referring to  FIG. 11C , in some embodiments, once the tissues of the bladder wall  6  are drawn into the openings  40 , a slidable pin  50  may be advanced across the opening  49  (see arrows) into or through the tissue, thereby holding the tissue in place, in which case the pin  50  may also serve dual propose as an electrode. 
         [0038]    In additional aspects, the framework splines and/or helically-biased wire of the present disclosure may include color-coded markings for visualization (e.g., using a cystoscope) to allow the physician to verify that the electrodes are properly positioned within the bladder prior to initiating the mapping and/or ablation steps. In addition, or alternatively, the framework splines and/or helically-biased wire may incorporate radiopaque markers along their length to allow the physician to verify their position within the bladder using, for example, X-ray imaging. In yet another embodiment, proper positioning of each electrode in apposition with the bladder wall may be achieved by measuring the impedance at each electrode. Any electrode(s) that fail to provide an impedance reading indicative of contact with the bladder wall may be re-positioned accordingly. In the event that one or more electrodes cannot be appropriately positioned in apposition with the bladder wall, any electrical measurements received from such electrodes may be disregarded during the mapping procedure. 
         [0039]    In other aspects, proper alignment of the mapping and ablation system of the present disclosure may be achieved using an insertion device that includes, for example, a shaft with a non-circular lumen configured to receive the mapping and ablation system in a specific orientation. The insertion device may include a guide (i.e., notch) to ensure that the mapping and ablation system is properly aligned with the non-circular lumen during loading. The insertion device may further include markings that correspond to the position of the patient, e.g., “ventral,” “dorsal,” “left,” and “right” to further ensure proper insertion into the patient&#39;s bladder. A series of incremental markings may also be included along the length of the insertion device to allow the physician to monitor how far within the patient the device has been inserted. The non-circular lumen of the insertion device may further allow the mapping and ablation system to automatically return (e.g., spring back) to the proper orientation if it becomes misaligned during insertion into the patient. 
         [0040]    In other aspects, the steerable catheter of the presently disclosed mapping and ablation system may include a central lumen through which a variety of medical instruments may be introduced. One such central lumen is shown as lumen  14  in  FIG. 1 . For example, an optical scope may be inserted through this central lumen to allow the physician to visually verify the location of the device within the bladder. Additional catheters may also be inserted through this central lumen to deliver fluids to keep the bladder wall hydrated and/or to expand the bladder to various volumes. Such fluids may also include therapeutics agents, or serve to cool the bladder during the ablation process. 
         [0041]    Examples of mapping electrode for use with medical ablation systems may be found, for example, in U.S. Patent Publication Nos. 2008/0249518 and 2002/0177765, each of which are hereby incorporated by reference in their entirety. As mapping electrodes, the wire connected to each electrode may be electrically coupled to the input of an electrical activity processing system (not shown), such as, for example, an electromyograph. Each electrode may be assigned an electrode location and an electrode channel within the electrical activity processing system. The electrical activity processing system may be configured to detect the intrinsic electrical activity of the cells comprising the tissue region that each of the electrodes is in contact with. The electrical activity processing system may then use the intrinsic electrical activity detected from each of the electrodes to provide a map of electrical activity and signal propagation throughout a given tissue region or organ. Based on this map, specific tissue regions exhibiting aberrant electrical activity as compared to the surrounding tissues may be identified. For example, the aberrant electrical activity may manifest as a region of elevated electrical activity compared to the surrounding (normal) tissue. 
         [0042]    For use as ablation electrodes, each wire may also be electrically coupled to an energy source (not shown) configured to selectively deliver ablation energy its respective electrode. For example, once a tissue region exhibiting elevated electrical activity has been identified, the electrode(s) that detected the elevated electrical activity may be selectively energized to focally ablate that tissue region. Various energy sources may be used to deliver thermal energy to the target tissue, including, for example, radiofrequency (RF) energy, irreversible electroporation (IRE energy), microwave electromagnetic energy, laser energy, and/or acoustic energy, among others. For example, the energy source may include a conventional RF power supply that operates at a frequency in the range from 200 KHz to 1.25 MHz, with a conventional sinusoidal or non-sinusoidal wave form. Suitable power supplies are capable of supplying an ablation current at a relatively low voltage, typically below 150V (peak-to-peak), usually being from 50V to 100V. It should be appreciated that a variety of RF energy generators that provide impedance, electrode temperature measurement and adequate energy output may be used to achieve appropriate ablation of the bladder tissue. RF energy may be delivered via a simultaneous mode with a single RF generator or multiple RF generators. Simultaneous delivery of ablation energy to 64 electrodes will require a generator capable of delivering approximately 640 W. This wattage may be achieved by connecting multiple generators, e.g., 64 generators with a capacity of 20 W in series. Power supplies capable of operating within these ranges are available from commercial vendors, such as RadioTherapeutics of San Jose, Calif. 
         [0043]    Once any one of medical devices disclosed herein are properly positioned within the bladder, the mapping function of each electrode may be activated to sense/detect the intrinsic electrical activity of the tissue region they are in contact with. Once a tissue region of the bladder wall exhibiting elevated electrical activity has been identified, ablation energy may be selectively delivered from the energy source to the electrode(s) that sensed the elevated electrical activity. This focal delivery of ablation energy causes the electrically overactive cell(s) of the identified tissue region to be heated to the point of cell death, thereby creating scar tissue that is incapable of conducting electrical impulses. 
         [0044]    The duration and/or intensity of the ablation energy may vary as necessary to achieve a satisfactory reduction of the elevated electrical activity. For example, ablation energy may be provided as a pulse, or series of pulses, of RF energy. The mapping function of the electrodes may then be re-established to determine if the identified tissue region continues to exhibit elevated electrical activity. In the event that the electrical activity within such sites remains elevated, the selected tissue region may be re-energized with ablation energy. This process may be repeated as necessary until the tissue region exhibits a desired level of electrical activity. The ability of these electrode arrays to repeatedly monitor and ablate regions of the bladder wall ensures that focal energy is delivered only to the target region, and without prolonging the duration or intensity of the energy. This targeted approach not only focuses the energy on the selected regions in need of ablation, but minimizes or eliminates unwanted and potentially harmful ablation of surrounding healthy/normal tissues. 
         [0045]    While the tissue region that is identified and ablated may be in direct contact with an electrode, it should be appreciated that the target tissue may be in the general vicinity of an electrode. In this situation, one or more of the electrodes adjacent to the target tissue may be energized such that the zone of ablation energy reaches (i.e., overlaps with) the target tissue. 
         [0046]    Once the mapping function of the electrodes has verified that the ablated tissue region no longer exhibits elevated electrical activity, the framework or helically-biased wire may be returned to the collapsed configuration within the catheter and withdrawn through the urethra. 
         [0047]    While the present disclosure relates generally to the application of thermal ablation energy to the target tissues identified by the mapping electrodes, it should also be appreciated the non-lethal energy, such as electrically stimulating energy or delivery of therapeutic agents through electroporation, may be administered to restore normal electrical activity to the cells of the target tissue.