Patent Description:
The instant disclosure relates to high-density mapping catheter tips and to map-ablate catheter tips for diagnosing and treating cardiac arrhythmias via, for example, radiofrequency (RF) ablation. In particular, the instant disclosure relates to flexible high-density mapping catheter tips, and to flexible ablation catheter tips that also have onboard high-density mapping electrodes.

Catheters have been used for cardiac medical procedures for many years. Catheters can be used, for example, to diagnose and treat cardiac arrhythmias, while positioned at a specific location within a body that is otherwise inaccessible without a more invasive procedure.

Conventional mapping catheters may include, for example, a plurality of adjacent ring electrodes encircling the longitudinal axis of the catheter and constructed from platinum or some other metal. These ring electrodes are relatively rigid. Similarly, conventional ablation catheters may comprise a relatively rigid tip electrode for delivering therapy (e.g., delivering RF ablation energy) and may also include a plurality of adjacent ring electrodes. It can be difficult to maintain good electrical contact with cardiac tissue when using these conventional catheters and their relatively rigid (or nonconforming), metallic electrodes, especially when sharp gradients and undulations are present.

Whether mapping or forming lesions in a heart, the beating of the heart, especially if erratic or irregular, complicates matters, making it difficult to keep adequate contact between electrodes and tissue for a sufficient length of time. These problems are exacerbated on contoured or trabeculated surfaces. If the contact between the electrodes and the tissue cannot be sufficiently maintained, quality lesions or accurate mapping are unlikely to result.

In <CIT>, it is described that a flexible electrode support is bent to define an arcuate shape that extends beyond the distal end of an associated guide body. At least one of the ends of the support is free of attachment to the distal end. By moving the free end, a user can push upon or pull against the structure to alter its arcuate shape to assure intimate contact with tissue.

In <CIT>, it is described that a combined electrical and chemical stimulation lead is especially adapted for providing treatment to the spine and nervous system. The stimulation lead includes electrodes that may be selectively positioned along various portions of the stimulation lead in order to precisely direct electrical energy to ablate or electrically stimulate the target tissue. The stimulation lead include single or multiple lead elements. The multiple lead element example can be selectively deployed to cover a targeted area. The lead may also include central infusion passageway(s) or lumen(s) that communicates with various infusion ports spaced at selected locations along the lead to thereby direct the infusion of nutrients/ chemicals to the target tissue. One example utilizes a dissolvable matrix for infusion as opposed to remote delivery through an infusion pump.

The foregoing discussion is intended only to illustrate the present field and should not be taken as a disavowal of claim scope.

The instant disclosure relates to high-density mapping catheter tips and to map-ablate catheter tips for diagnosing and treating cardiac arrhythmias via, for example, RF ablation. In particular, the instant disclosure relates to flexible high-density mapping catheter tips, and to flexible ablation catheter tips that also have onboard high-density mapping electrodes. Some embodiments include irrigation.

There is described herein a high-density mapping catheter in accordance with claim <NUM>.

Also described herein is a high-density mapping catheter which comprises an elongated catheter body comprising a proximal end and a distal end, and defining a catheter longitudinal axis extending between the proximal and distal ends; and a flexible, distal tip assembly at the distal end of the catheter body and adapted to conform to tissue, the flexible distal tip assembly comprising a plurality of microelectrodes mounted so that at least some of the microelectrodes are moveable relative to other of the microelectrodes.

Also described herein is a high-density mapping catheter which comprises the following: (i) a catheter shaft comprising a proximal end and a distal end, the catheter shaft defining a catheter shaft longitudinal axis extending between the proximal end and the distal end; (ii) a flexible tip portion located adjacent to the distal end of the catheter shaft, the flexible tip portion comprising a flexible framework comprising nonconductive material; and (iii) a plurality of microelectrodes mounted on the flexible framework and forming a flexible array of microelectrodes adapted to conform to tissue; wherein the flexible framework is configured to facilitate relative movement among at least some of the microelectrodes relative to other of the microelectrodes; and wherein the nonconductive material insulates each microelectrode from other microelectrodes. The flexible array of microelectrodes may be, for example, a planar or cylindrical array of microelectrodes formed from a plurality of rows of longitudinally-aligned microelectrodes. The flexible array may further comprise, for example, a plurality of electrode-carrying arms or electrode-carrier bands.

Also described herein is a flexible, high-density mapping-and-ablation catheter comprising the following: (a) a catheter shaft comprising a proximal end and a distal end, the catheter shaft defining a catheter shaft longitudinal axis; (b) a first plurality of microelectrodes mounted on a first flexible framework of nonconductive material and forming a first flexible array of microelectrodes adapted to conform to tissue; wherein the first flexible framework is configured to facilitate relative movement among at least some of the microelectrodes; and wherein the nonconductive material insulates each microelectrode from other microelectrodes; and (c) a flexible tip portion located adjacent to the distal end of the catheter shaft, the flexible tip portion comprising a second flexible framework constructed from conductive material.

Also described herein is a flexible, high-density mapping-and-ablation catheter comprising the following: (i) a catheter shaft comprising a proximal end and a distal end, the catheter shaft defining a catheter shaft longitudinal axis; (ii) a first plurality of microelectrodes mounted on a first flexible framework of nonconductive material and forming a first flexible array of microelectrodes adapted to conform to tissue; wherein the first flexible framework is configured to facilitate relative movement among at least some of the microelectrodes in the first plurality of microelectrodes relative to other of the microelectrodes in the first plurality of microelectrodes; and wherein the nonconductive material insulates each microelectrodes in the first plurality of microelectrodes from other microelectrodes in the first plurality of microelectrodes; (iii) a second plurality of microelectrodes mounted on a second flexible framework of nonconductive material and forming a second flexible array of microelectrodes adapted to conform to tissue; wherein the second flexible framework is configured to facilitate relative movement among at least some of the microelectrodes in the second plurality of microelectrodes relative to other of the microelectrodes in the second plurality of microelectrodes; and wherein the nonconductive material insulates each microelectrodes in the second plurality of microelectrodes from other microelectrodes in the second plurality of microelectrodes; and (iv) an ablation region located between the first flexible framework and the second flexible framework.

Also described herein is a delivery adapter which comprises a body that comprises a dilator support pocket, an internal compression cone, and a guide sheath connector. The delivery adapter body may be separable or splittable into a first portion and a second portion.

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

Several embodiments of flexible, high-density mapping catheters and map-ablate catheters are disclosed herein. In general, the tip portions of these various catheters comprise an underlying support framework that is adapted to conform to and remain in contact with tissue (e.g., a beating heart wall). Details of the various embodiments of the present disclosure are described below with specific reference to the figures.

<FIG> depict, and <FIG> relates to, a tip portion <NUM>A of a high-density mapping catheter according to a first embodiment. As shown in <FIG>, the tip portion <NUM>A includes interlocking rings or bands <NUM> of nonconductive material (e.g., polyether-etherketone or PEEK) forming the underlying support framework for a plurality of microelectrodes. In this embodiment, a circumferential or helical through-cut pattern <NUM> defines a plurality of dovetail surfaces <NUM>. Each dovetail surface has a microelectrode <NUM> attached to it, thereby defining a flexible array of microelectrodes that are arranged in circumferential rings or bands. The electrodes <NUM> are also aligned in longitudinally-extending (e.g., parallel to a catheter longitudinal axis <NUM>) rows of electrodes that are able to flex or move slightly relative to each other during use of the catheter. The nonconductive material individually insulates each microelectrode.

The nonconductive substrate on which the button electrodes <NUM> are mounted may comprise PEEK. The tip <NUM>A includes a radiopaque tip cap <NUM> that facilitates fluoroscopy visualization. The tip cap may be domed shaped, hemispherical, flat-topped, tapered, or any other desired general shape.

In this embodiment of the tip portion <NUM>A, there are sixty-four discrete microelectrodes <NUM>, and a separate lead (shown in, for example, <FIG> and <FIG>) wire extends to each of these electrodes from the proximal end of the catheter. In a preferred version of this catheter, the catheter is either 7F or <NUM>. The flexible tip helps to facilitate and ensure stability during, for example, cardiac motion, which in turn makes it possible to accurately map cardiac electrical activity because of the sustained electrode contact that is possible. The circumferential or helical cuts <NUM>, which may be formed by a laser, create a plurality of serpentine gaps that permit the tip to flex as the cardiac wall moves in a beating heart. When a plurality of circumferential through-cuts are used, this creates a plurality of dovetailed (or 'saw-toothed') bands <NUM>. <FIG> depicts the flat-pattern design for one of these bands <NUM> according to the first embodiment. As clearly shown in <FIG>, the pattern includes a circumferential waistline or ring <NUM> defined between a circumferentially-extending proximal edge <NUM> and a circumferentially-extending distal edge <NUM>. Each of these edges is interrupted by a plurality of proximally-extending pads <NUM> or distally-extending pads <NUM>. Each pad in this embodiment has the shape of a truncated isosceles triangle with sides S and a base B. Two adjacent proximally-extending pads define a proximally-opening pocket <NUM> between them. Similarly, on the opposite side of the circumferential waistline <NUM>, two distally-extending pads <NUM> that are adjacent to each other define a distally-opening pocket <NUM>.

As may be clearly seen in <FIG>, when two of these dovetailed bands are connected, each distally-extending pad <NUM> flexibly interlocks in a proximally-opening dovetailed pocket <NUM>, and each proximally-extending pad <NUM> flexibly interlocks in a distally-opening dovetail pocket <NUM>. It is also shown in <FIG>, each pad <NUM>, <NUM>, in this embodiment, includes an aperture <NUM> in which a microelectrode will be mounted. Each aperture extends through a pad, from a pad outer surface to a pad inner surface.

Rather than having circumferential through-cuts <NUM>, which define a plurality of individual electrode-carrier bands, the flexible tip depicted in <FIG> could be formed by a continuous helical cut.

<FIG> are similar to <FIG>, respectively, but depict a tip portion <NUM>B of a high-density mapping catheter according to a second embodiment. In this embodiment, circumferential through-cuts <NUM> define a plurality of discs <NUM> on which microelectrodes <NUM> are mounted. Alternatively, a helical cut could be used to form the flexible tip configuration shown in <FIG>. As with the embodiment shown in <FIG>, in the embodiment depicted in <FIG>, the microelectrodes <NUM> are mounted in a nonconductive material such as PEEK.

A third embodiment of a tip portion <NUM>C is depicted in <FIG>. In this embodiment, however, unlike the embodiment <NUM>A shown in <FIG>, the interlocking, dovetailed pattern is formed from conductive material since this is an ablation tip. As shown to best advantage in <FIG>, the distal end <NUM> of this flexible ablation tip includes a pair of symmetrically-placed, high-density microelectrodes <NUM> for mapping. As also shown to best advantage in <FIG>, this configuration includes two front-facing irrigation ports <NUM>, and a thermocouple or a temperature sensor <NUM>. The mapping electrodes <NUM> are mounted in a nonconductive insert <NUM> to electrically insulate these mapping electrodes from the remainder of the ablation tip. In this particular configuration, the flexible ablation tip is <NUM> millimeters long. It should also be noted that, in this embodiment, the pads and pockets defined by the serpentine cuts <NUM> are smaller than the corresponding pads and pockets depicted in, for example, <FIG>. In this ablation tip embodiment <NUM>C, the individual pads <NUM> do not carry microelectrodes and, therefore, the pads can be smaller in this configuration of the ablation tip than they are in the high-density mapping tips.

<FIG> depict an ablation tip portion <NUM>° and high-density mapping electrode according to a fourth embodiment. This embodiment is a <NUM> Fr catheter having a <NUM> millimeters long, flexible ablation electrode manufactured from, for example, platinum. In this design, four high-density mapping electrodes <NUM> are mounted through the distal pads <NUM> of pad structures. Also, each pad structure includes a larger distal pad and a smaller proximal pad <NUM>; and each microelectrode <NUM> is mounted through an aperture <NUM> extending through a distal pad <NUM>. In this configuration <NUM>°, two carrier bands are interconnected by a linking band <NUM>, a most-proximal carrier band <NUM> is connected with the distal end <NUM> of the catheter shaft <NUM>, and a most-distal carrier band is connected to an end cap <NUM>. In this embodiment, each of the four mapping electrodes is individually insulated and has its own lead wire (shown in, for example, <FIG>. And <NUM>) extending from the electrode <NUM> out the proximal end of the catheter. Similar to what occurs in each of the embodiments already discussed, this is an irrigated configuration. Thus, during use of the catheter, irrigant (e.g., cooled saline) is routed from the proximal end of the catheter, through the catheter shaft, and out of the serpentine gaps formed in the tip.

<FIG> provide details concerning the tip portion <NUM>E of a high-density mapping catheter according to a fifth embodiment. As shown to good advantage in <FIG>, this catheter tip <NUM>E gets its flexibility from a plurality of circumferential, dovetail cuts that define a plurality of serpentine gaps <NUM> between alternating electrode-carrier bands (or carrier bands) <NUM> and linking bands <NUM>. The working portion of the embodiment <NUM>E depicted in <FIG> is approximately <NUM> millimeters long (see dimension L in <FIG>) and has a diameter of <NUM> Fr to <NUM> Fr (see dimension D in <FIG>). In this embodiment, the longitudinal electrode spacing between adjacent microelectrode (see dimension SL in <FIG>) is approximately <NUM> millimeters, and the circumferential electrode spacing between adjacent microelectrode (see dimension SC in <FIG>) is also approximately <NUM> millimeters. An end cap <NUM> may also be present as shown in, for example, <FIG>.

As shown to good advantage in <FIG>, the fifth embodiment <NUM>E shows a plurality of electrode-carrier bands <NUM> separated by a plurality of linking bands <NUM>. Thus, there is one linking band between directly adjacent pairs of carrier bands. In this configuration, each carrier band includes a plurality of bowtie-shaped or hourglass-shaped structures <NUM> (see for example, <FIG>). Further, in this configuration, each of these bowtie-shaped structures <NUM> comprises a distal pad <NUM> and a proximal pad <NUM>, separated by a narrowed region or waist <NUM>. In this configuration, each distal pad <NUM> of each carrier band <NUM> has an electrode-mounting aperture <NUM> (e.g., <NUM> diameter) through it.

Further, as shown to best advantage in <FIG> and <FIG>, there is a circumferential connector <NUM> between each pair of adjacent pad structures. The circumferential connectors <NUM>, along with the waist <NUM> of each pad structure <NUM>, together define a circumferential ring. In this embodiment, the bowtie-shaped or hourglass-shaped pad structures <NUM> are essentially symmetrical about the waist <NUM> except for the existence of an electrode-mounting aperture <NUM> in each of the distal pads <NUM>.

As shown in <FIG>, a distally-opening slot <NUM> is present between adjacent, distally-extending pads <NUM>. Similarly, a proximally-opening slot <NUM> is present between adjacent, proximally-extending pads <NUM>. Looking at a single electrode-carrier band, the circumferentially-extending pad connectors <NUM>, together with the waists <NUM> of each pad structure <NUM>, define a carrier band waistline that extends around the circumference of the tip portion <NUM>E of the catheter.

In this configuration, as shown in <FIG>, each linking band <NUM> also comprises a connected series of bowtie-shaped structures <NUM>. In this particular embodiment, the bowtie-shaped pad structures <NUM> of the linking bands <NUM> are larger than the bowtie-shaped pad structures <NUM> of the carrier bands <NUM>.

<FIG> and <FIG> are views with portions of the catheter removed to show inner details of the catheter tip portion of <NUM>E. In <FIG>, it is possible to see the individual lead wires <NUM> extending longitudinally through the catheter shaft and connecting with each of the microelectrodes <NUM>. It is also possible to see an internal spring <NUM> in this figure. This spring helps the tip portion <NUM>E of the catheter maintain its flexibility, and it helps create the gaps between adjacent carrier bands <NUM> and linking bands <NUM>. <FIG> depicts an internal irrigation lumen <NUM> that acts as an irrigant distribution manifold.

The button electrodes or microelectrodes <NUM> may have a diameter between <NUM> and <NUM> millimeters. The lead wires extending through the catheter shaft to each of these electrodes may comprise <NUM> AWG wire. As previously described in connection with other embodiments, an end cap <NUM> may be metallic, or otherwise radiopaque, to facilitate visualization of the catheter tip during use of a fluoroscope.

<FIG> depict aspects of a sixth embodiment of a tip portion <NUM>F. <FIG> depicts a cylindrical-shaped portion <NUM> of nonconductive material that has been laser cut to define an interlocking, but flexible pattern <NUM> (see <FIG> shows what that pattern <NUM> looks like when it is laid out flat rather than having the cylindrical shape depicted in <FIG>.

In this embodiment, a plurality of electrode-carrier bands (or carrier bands) <NUM> and a plurality of linking bands <NUM> are present. <FIG> is similar to <FIG>, but shows adjacent pad structures <NUM> according to the sixth embodiment, as also shown in <FIG> and <FIG>. In this configuration, the carrier bands <NUM> are not completely separate from the adjacent linking bands <NUM>. In particular, as may be clearly seen in <FIG> and <FIG>, this embodiment includes a plurality of inter-band bridges or connectors <NUM>. All of the bands <NUM>, <NUM> are thereby loosely interconnected, and one band cannot move completely independently of any other band comprising the working portion of the high-density mapping catheter tip <NUM>F.

As also clearly shown in <FIG>, in this embodiment, each pad structure <NUM> is not the symmetrical bowtie-shaped structure <NUM> depicted in, for example, <FIG>. Rather, in the sixth embodiment, the distal tabs <NUM> of each pad structure <NUM> are larger than the corresponding proximal pads <NUM> of the pad structure <NUM>. The electrode apertures <NUM> extend through this larger distal pad <NUM>.

As shown to good advantage in <FIG>, slots are formed between adjacent pad structures <NUM>. In particular, a relatively shallow, proximally-opening tab slot <NUM> is formed between adjacent proximal pads <NUM>. Similarly, a relatively deep, distally-opening tab slot <NUM> is formed between adjacent pairs of distal pads <NUM>. As described above with reference to <FIG>, circumferentially-extending connectors <NUM> are again present between adjacent pad structures <NUM>. All of these connectors on a single carrier band <NUM>, together with the waists <NUM> of each pad structure comprising part of that same carrier band, form a carrier band waistline.

<FIG> depicts a tab structure <NUM> from a linking band <NUM>. Each linking band comprises a plurality of these tab structures. Each tab structure includes a relatively-longer, proximally-extending tab (or'proximal tab') <NUM> in a relatively-shorter, distally-extending tab (or'distal tab') <NUM>. <FIG> depicts two adjacent tab structures <NUM> of a single linking band <NUM>. A proximally-opening pocket <NUM> is defined between adjacent proximal tabs <NUM>. Similarly, a distally-opening pocket is defined between adjacent distal tabs. A circumferentially-extending, tab-structure connector <NUM> connects adjacent tab structures <NUM> and helps to form the proximally-opening pocket <NUM> and a distally-opening pocket <NUM>. In other words, each linking band <NUM> includes a circumferentially-extending proximal edge <NUM> and a circumferentially-extending distal edge <NUM>. The proximal edge defines a series of proximally-extending tabs <NUM> and proximally-opening pockets <NUM>, and the distal edge <NUM> of each linking band <NUM> forms a plurality of distally-extending tabs and distally-opening pockets <NUM>.

<FIG> also relates to the sixth embodiment. In particular, <FIG> depicts a single linking band <NUM> (on the left) flexibly interlocked with a single carrier band <NUM> (on the right). As shown, each proximally-extending tab <NUM> is flexibly interlocked in a corresponding distally-opening slot <NUM> in a carrier band <NUM>. Similarly, each distally-extending pad <NUM> of the carrier band is flexibly interlocked in a corresponding proximally-opening pocket <NUM> in the linking band <NUM>.

Each tab structure of the linking band is an asymmetrical bowtie configuration. Similarly, each pad structure <NUM> of the carrier band <NUM> is also an asymmetrical bowtie configuration. The serpentine gap extending between the linking band <NUM> and the carrier band <NUM> (e.g., a laser cut gap) defines the tabs and the pockets of the linking band, and define the complementary pads and slots, respectively, of the carrier bands.

<FIG> depicts a fully-assembled tip portion <NUM>F of a high-density mapping catheter according to the sixth embodiment. The fully assembled tip includes a most-proximal band (or shaft-transition band) <NUM>, and a most-distal band (or end-cap-transition band) <NUM>. An end cap <NUM> may be platinum or some other radiopaque material to facilitate visualization on a fluoroscopy screen. As may be seen in <FIG>, the button electrodes or microelectrodes <NUM> are slightly raised off the outer surface of the laser cut PEEK material. This is also clearly visible in <FIG>, which shows the catheter tip in a slightly-flexed configuration. With the electrodes raised slightly as shown, better electrical contact can be maintained between the electrodes and the tissue. In the embodiment depicted in <FIG>, there are thirty-two mapping electrodes <NUM> mounted in the laser-cut PEEK material. In this particular design, the catheter shaft is <NUM> Fr or <NUM> Fr.

<FIG> also depict the sixth embodiment. In particular, <FIG> shows an entire catheter <NUM>, including an electrical connector <NUM> and a control handle <NUM> near the proximal portion of the catheter and a flexible high-density mapping tip <NUM>F at the distal end of the catheter <NUM>. <FIG> is an enlarged view of the circled portion of <FIG>.

<FIG> depicts the distal tip portion <NUM>G of a high-density mapping catheter according to a seventh embodiment. Similar to some of the configurations discussed above, this tip portion includes a metallic cap (e.g., a platinum cap) <NUM> or otherwise radiopaque cap to facilitate visualization on fluoroscopy. This specific embodiment <NUM>G is different from the embodiment <NUM>F depicted, for example, in <FIG>, since the electrode apertures <NUM> in this embodiment are located through the distal pads <NUM> of pad structures of electrode carrier bands <NUM> that are relatively smaller than the tab structures of the linking bands <NUM>. In this seventh embodiment, each electrode-carrier band <NUM> includes a plurality of bowtie-shaped pad structures that are circumferentially arranged around the longitudinal axis of the catheter. Similarly, each linking band <NUM> comprises a plurality of bowtie-shaped tab structures also arranged circumferentially around the catheter longitudinal axis. In this particular configuration of the tip portion <NUM>G, however, the bowtie-shaped tab structures are relatively larger than the bowtie-shaped pad structures of the electrode-carrier bands <NUM>. By changing the relative size of the distal and proximal tabs, and the relative size of the corresponding or related distal and proximal pads, the performance characteristics of the tip portion of the high-density mapping catheter can be adjusted.

<FIG> depicts an eighth embodiment of a high-density mapping tip portion <NUM>H. In this embodiment, a <NUM> Fr catheter includes a flexible array of microelectrodes <NUM> that is similar to, but shorter than, the flexible array of microelectrodes depicted in, for example, <FIG>. In this particular design, however, <NUM> ring electrodes <NUM>, <NUM>, <NUM> are located at each longitudinal end of the flexible array of <NUM> diameter microelectrodes <NUM>. In the depicted embodiment, the most-proximal circumferential ring of microelectrodes <NUM> is located approximately <NUM> (see dimension SR in <FIG>) from the most-proximal circumferential edge <NUM> of array. As shown, there are sixteen microelectrodes arranged in four longitudinally-extending rows of four electrodes, each row radially offset from the next row by <NUM>°. The longitudinal spacing between adjacent microelectrodes may be, for example, <NUM>. There are two ring electrodes <NUM>, <NUM> spaced <NUM> from each other and located proximal to the most-proximal circumferential edge <NUM> of the flexible array of microelectrodes. There is a third <NUM> ring electrode <NUM> located distal of the most-distal edge <NUM> of the flexible array of microelectrodes. In this particular configuration, there is also a <NUM> long metal tip <NUM> that could be used as an additional electrode.

<FIG> depict the distal portion <NUM>I of a map-and-ablate catheter according to a ninth embodiment. Similar to what is shown in <FIG>, the ninth embodiment shown in <FIG> includes a flexible array of microelectrodes <NUM> comprising sixteen microelectrodes arranged in four longitudinally extending rows of four where each of these rows is radially offset by <NUM>° from the next adjacent row of electrodes. In this embodiment, however, the most-distal end of the catheter comprises a flexible ablation tip <NUM>. This ablation tip may be, for example, a Cool Flex™ ablation tip sold by St. Jude Medical, Inc. Paul, Minnesota. During use, irrigant would flow down the catheter shaft and exit through the serpentine gaps in the flexible array of microelectrodes and through the openings in the flexible ablation tip. This tip would advantageously conform to the cardiac tissue during both mapping and ablation procedures.

<FIG> depict a tip portion <NUM>J of a map-and-ablate catheter according to a tenth embodiment. Moving distally down the catheter shaft toward the most-distal end, two <NUM> ring electrodes are encountered, including a most-proximal ring <NUM> electrode and a most-distal ring electrode <NUM>. Next, a proximal short flexible array <NUM> of eight <NUM> diameter microelectrodes, mounted in four rows of two microelectrodes, is encountered. In this embodiment, these microelectrodes project from the outer surface of the catheter approximately <NUM> and are longitudinally spaced from each other by approximately <NUM>. Connected to the distal-side of this short flexible array of microelectrodes is an ablation region <NUM> that is approximately <NUM> long and that includes a plurality of irrigation holes <NUM>. Distal of the ablation region is another, rather short flexible array <NUM> of microelectrodes. In this particular configuration, the distal flexible array <NUM> of microelectrodes is similar to the proximal, flexible array <NUM> of microelectrodes. Finally, in this map ablate catheter, the distal end includes a metallic cap <NUM> that may be used for mapping, ablation, and/or visualization on fluoroscopy.

<FIG> depict a tip portion <NUM>K comprising a flexible array of microelectrodes according to an eleventh embodiment. This planar array (or 'paddle' configuration) of microelectrodes comprises four side-by-side, longitudinally-extending arms <NUM>, <NUM>, <NUM>, <NUM> forming the flexible framework on which the thirty-two <NUM> long x <NUM> diameter ring electrodes <NUM> are carried. As discussed further below, a few of these ring electrodes (see, for example, rings <NUM> and <NUM> in <FIG>) may be slightly longer. The four ring-electrode-carrier arms comprise a first outboard arm <NUM>, a second outboard arm <NUM>, a first inboard arm <NUM>, and a second inboard arm <NUM>. These arms are laterally separated from each other by approximately <NUM> in this embodiment. Each of the four arms carries eight small ring electrodes <NUM>, spaced along its length. In the depicted embodiment, these small ring-shaped microelectrodes are longitudinally separated from each other by approximately <NUM>. Although each of the paddle catheters depicted in <FIG> shows four arms, the paddle could comprise more or fewer arms.

<FIG> is an isometric, fragmentary view of the planar array. As shown to best advantage in <FIG>, the most-distal ring electrode on the first outboard arm <NUM> is slightly enlarged as is the most-proximal ring electrode <NUM> on the second outboard arm <NUM>. These slightly enlarged electrodes <NUM>, <NUM> (e.g., in the depicted embodiment, these microelectrodes are slightly longer than the other ring electrodes) can be used, for example, for more precise localization of the flexible array in mapping and navigation systems. It is also possible to drive ablation current between these enlarged electrodes, if desired, for bipolar ablation, or, alternatively to drive ablation current in unipolar mode between one or both of these enlarged ring electrodes and, for example a patch electrode located on a patient (e.g., on the patient's back). Similarly, the microelectrodes <NUM> (on this or any of the other paddle catheters) can be used to perform unipolar or bipolar ablation. Alternatively or concurrently, current could travel between one or more of the enlarged electrodes and any one or all of the microelectrodes. This unipolar or bipolar ablation can create specific lines or patterns of lesions. As also may be seen in <FIG>, there may be a distal member (or 'button') <NUM> where one or more of the arms come together. This distal member may be constructed from metal or some other radiopaque material to provide fluoroscopy visualization and semi-independent planar movement between the outer and inner arms.

As shown to best advantage in <FIG>, the planar, flexible arms conform to trabeculated tissue <NUM>, enabling a physician to maintain contact between several of the electrodes and the tissue. This enhances the accuracy, and the corresponding diagnostic value, of the recorded information concerning the heart's electrical activity.

<FIG> depict a flexible array of microelectrodes at the tip portion <NUM>L of a high-density mapping catheter according to a twelfth embodiment. In this configuration, there are four <NUM> ring electrodes (depicted with a <NUM> longitudinal spacing) mounted on the distal end of the catheter shaft, proximal to a proximal bushing <NUM> and to the proximal ends of ring electrode carrier arms <NUM>', <NUM>', <NUM>', <NUM>'. In this embodiment, each of the four electrode carrying arms has eight small ring electrodes <NUM> (microelectrodes) mounted on it. The four arms are designed to maintain the thirty-two small ring electrodes in a spaced relationship so that each small ring electrode can capture separate data about the electrical activity of the cardiac tissue adjacent to the microelectrodes.

<FIG> depict two variations <NUM>M, <NUM>N of a similar tip portion comprising a flexible array of microelectrodes <NUM>'. In both variations of this particular configuration, there are sixteen small ring electrodes <NUM>' mounted on four small arms <NUM>", <NUM>", <NUM>", <NUM>" rather than the thirty-two ring electrodes <NUM> depicted in <FIG>. These small ring electrodes (<NUM> long x <NUM> diameter) are longitudinally separated from each other by approximately <NUM> in this embodiment, and the electrode carrying arms are laterally separated from each other by approximately <NUM>. Further, in the variation <NUM>N depicted in <FIG>, the high-density mapping catheter also includes two tethers <NUM> extending transverse across and interconnecting the four electrode carrying arms. Although two tethers are shown in <FIG>, any number of tethers could be used, including a single tether. The tether or tethers <NUM> help maintain a predictable relationship between the electrode carrying arms <NUM>", <NUM>", <NUM>", <NUM>" by controlling, for example, how each electrode carrying arm may move relative to the other electrode carrying arms. Each tether <NUM> may comprise a tensile element, such as slender mono- or multi-filament nylon thread or suture-like material. The tethers may be connected with or to the electrode carrying arm in a variety of ways. In <FIG>, for example, the tethers <NUM> have been adhered or ultrasonically welded to each of the electrode carrying arms <NUM>", <NUM>", <NUM>", <NUM>". Alternatively, a tether could be tied to or looped around the arms. Reflowing the device during the manufacturing process may allow the tether or tethers to become incorporated into the arms polymer insulation, thereby securing the tether to the arms and minimizing the need for tying, looping, gluing, or otherwise attaching the tethers to the arms. The tethers <NUM> are configured to also collapse or fold during insertion of the catheter into a delivery sheath or introducer.

<FIG> depicts yet another embodiment of a tip portion <NUM>° comprising a flexible array of microelectrodes. This configuration is most similar to the first variation <NUM>M of the thirteenth embodiment, which is depicted in <FIG>. However, in the fourteenth embodiment, there are two additional ring electrodes <NUM> mounted near the distal end of each outboard arm.

<FIG> depicts an alternative variation of the high-density mapping catheter embodiment <NUM> depicted in <FIG>. In particular, in <FIG>, an irrigation port <NUM> is present at the distal end of a proximal bushing <NUM>', and the irrigation port is positioned to deliver irrigant to or near the point where the electrode carrying arms exit from the distal end of the proximal bushing that is mounted on the distal end of the catheter shaft in this embodiment. If desired, a second irrigation port (not shown) may be located near the distal intersection of the electrode carrying arms. In fact, if desired, multiple irrigation ports (not shown) could be present at various positions along the electrode carrying arms <NUM>", <NUM>", <NUM>", <NUM>". <FIG> is an enlarged, fragmentary view of the irrigation port <NUM> on the proximal bushing <NUM>'. Further, while only one irrigation port <NUM> is illustrated on the proximal bushing <NUM>', multiple irrigation ports could be present on the proximal bushing (e.g., one or more on each side of the planar array of microelectrodes) to provide more uniform irrigant distribution at or near the proximal apex of the arms <NUM>", <NUM>", <NUM>", <NUM>". Likewise, a distal irrigation port set (not shown) comprising multiple ports could be included at or near the distal apex of the arms <NUM>", <NUM>", <NUM>", <NUM>".

<FIG> is a fragmentary, isometric view of the distal portion of the catheter shaft of a high-density mapping catheter. In this view, portions of the catheter shaft have been removed to reveal a sensor <NUM> located just proximal to the proximal bushing. A variety of sensors may be incorporated at this location, or at similar locations, in the high-density mapping catheters described herein. These sensors may be mounted in the catheter shaft, as shown in <FIG>, or they may be mounted at other locations (e.g., along the electrode carrying arms of the high-density mapping paddle and/or at the distal apex or joint of the tip portion). In one embodiment, the sensor <NUM> is a magnetic field sensor configured for use with an electromagnetic localization system such as the MediGuide™ System sold by St. Jude Medical, Inc. Paul, Minnesota.

<FIG> is an exploded, isometric view of one embodiment of a delivery adapter <NUM> designed to facilitate delivery of a paddle catheter into and through a guiding sheath or introducer <NUM> having a circular cross section. As depicted in this figure, the delivery adapter <NUM> comprises a first portion 218A having pins <NUM> extending therefrom, and a second portion 218B having complementary pin-receiving holes <NUM> therein. When these portions 218A, 218B are assembled, a proximal pocket configured to support or hold the distal end of a dilator hub <NUM> (labeled in <FIG>) is formed. In particular, the first portion 218A of the delivery adapter includes a first part 226A of that pocket, and the second portion 218B of the delivery adapter comprises a second part 226B of the pocket. In this particular embodiment, a dilator shaft channel is also present and comprises a first trough 230A formed in the first portion 218A of the delivery adapter <NUM> and a second trough 230B formed in the second portion 218B of the delivery adapter <NUM>. Also, the distal side of the delivery adapter, in this embodiment, comprises a threaded hole (e.g., a female luer lock) 232A, 232B adapted to thread onto a shaft or fitting (e.g., a male luer lock) <NUM> extending proximally from the proximal end of the guiding sheath <NUM>.

As best seen in <FIG>, the interior of the delivery adapter, between the proximal pocket 226A, 226B and the threaded hole 232A, 232B defines a hollow compression or folding cone 236A, 236B. In one embodiment, for example, the lateral cross-sectional shape of the proximal end of this compression cone is elliptical or nearly elliptical, and the lateral cross-sectional shape of the distal-most portion of the compression cone is circular or near circular, matching the channel through a hub <NUM> of the guiding sheath <NUM>. The compression cone is thereby configured or adapted to compress the relatively flat paddle of the high-density mapping catheter into a configuration having a substantially circular cross-sectional shape or other shape that fits into the proximal opening in the guiding sheath hub <NUM>. It should also be noted that the delivery adapter may be splittable for easy removal when used with a splittable guiding sheath.

Referring now most specifically to the various views comprising <FIG>, one use of the delivery adapter <NUM> just described in connection with <FIG> is described next. In this use, a dilator <NUM> is inserted into and through the delivery adapter <NUM> and seated in the pocket 226A, 226B formed in the proximal side of the assembled delivery adapter. The assembled delivery adapter <NUM>, with the dilator <NUM> in place, is then mounted to the guiding sheath <NUM> as shown in <FIG>. The dilator <NUM>, shown by itself in <FIG>, is then removed from the delivery adapter <NUM> and guiding sheath <NUM>, as may be seen in the lefthand portion of <FIG>.

Next, as also shown in view <FIG>, the paddle <NUM> of a high-density mapping catheter is inserted into the proximal end of the compression cone 236A, 236B of the delivery adapter. In <FIG>, the electrode carrying arms of the paddle have been inserted further into the compression cone. As the electrode carrying arms of the panel impact the angled side surfaces of the compression cone formed in the delivery adapter <NUM>, the electrode carrying arms are compressed towards each other. When the arms have been sufficiently compressed together (i.e., into a side-by-side, touching or near-touching configuration), the paddle then fits into the proximal end of the port through the guiding sheath or introducer <NUM> and may be pushed through the hemostasis valve (not shown) in the hub <NUM> at the proximal end of the guiding sheath <NUM>. As shown in <FIG>, as the paddle portion <NUM> of the high-density mapping catheter exits from the distal end of the guiding sheath <NUM>, the electrode carrying arms comprising the paddle remain compressed together. Once the electrode carrying arms of the paddle exit from the distal end of the shaft or tube of the guiding sheath, the electrode carrying arms expand back into the paddle configuration, as best shown in <FIG>.

In each of the embodiments depicted in, for example, <FIG>, one or more of the ring electrodes <NUM> could be used to send pacing signals to, for example, cardiac tissue. Further, the arms (or the understructure of the arms) comprising the paddle structure (or multi-arm, electrode-carrying, flexible framework) at the distal end of the catheters depicted in <FIG> are preferably constructed from a flexible or spring-like material such as Nitinol. The construction (including, for example, the length and/or diameter of the arms) and material of the arms can be adjusted or tailored to be created, for example, desired resiliency, flexibility, foldability, conformability, and stiffness characteristics, including one or more characteristics that may vary from the proximal end of a single arm to the distal end of that arm, or between or among the plurality of arms comprising a single paddle structure. The foldability of materials such as Nitinol provide the additional advantage of facilitating insertion of the paddle structure into a delivery catheter or introducer, whether during delivery of the catheter into the body or removal of the catheter from the body at the end of a procedure. Although a short guide sheath <NUM> (used, for example, for epicardial access) is depicted in <FIG> and <FIG>, a longer guide sheath (used, for example, to access the heart from a femoral access point) could be used to introduce the flexible high-density mapping and ablation tips described herein.

Among other things, the disclosed catheters, with their plurality of microelectrodes, are useful to (<NUM>) define regional propagation maps on one centimeter square areas within the atrial walls of the heart; (<NUM>) identify complex fractionated atrial electrograms for ablation; (<NUM>) identify localized, focal potentials between the microelectrodes for higher electrogram resolution; and/or (<NUM>) more precisely target areas for ablation. These mapping catheters and ablation catheters are constructed to conform to, and remain in contact with, cardiac tissue despite potentially erratic cardiac motion. Such enhanced stability of the catheter on a heart wall during cardiac motion provides more accurate mapping and ablation due to sustained tissue-electrode contact. Additionally, the catheters described herein may be useful for epicardial and/or endocardial use. For example, the planar array embodiments depicted in <FIG> may be used in an epicardial procedure where the planar array of microelectrodes is positioned between the myocardial surface and the pericardium. Alternatively the planar array embodiments may be used in an endocardial procedure to quickly sweep and/or analyze the inner surfaces of the myocardium and quickly create high-density maps of the heart tissue's electrical properties.

Although several embodiments have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit of the present disclosure. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the present teachings. The foregoing description and following claims are intended to cover all such modifications and variations.

Various embodiments are described herein of various apparatuses, systems, and methods. Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. It will be understood by those skilled in the art, however, that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. Those of ordinary skill in the art will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments, the scope of which is defined solely by the appended claims.

Reference throughout the specification to "various embodiments," "some embodiments," "one embodiment," "an embodiment," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in various embodiments," "in some embodiments," "in one embodiment," "in an embodiment," or the like, in places throughout the specification are not necessarily all referring to the same embodiment. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features structures, or characteristics of one or more other embodiments without limitation.

Claim 1:
A high-density mapping catheter comprising the following:
a catheter shaft comprising a proximal end and a distal end, the catheter shaft defining a catheter shaft longitudinal axis extending between the proximal end and the distal end;
a flexible tip portion located adjacent to the distal end of the catheter shaft, the flexible tip portion comprising a flexible framework comprising nonconductive material; and
a plurality of microelectrodes (<NUM>) mounted on the flexible framework and forming a flexible array of microelectrodes adapted to conform to tissue, wherein the microelectrodes (<NUM>) are ring electrodes; wherein the flexible framework is configured to facilitate relative movement among at least some of the microelectrodes (<NUM>) relative to other of the microelectrodes (<NUM>); and wherein the nonconductive material insulates each microelectrode from other microelectrodes (<NUM>);
wherein the plurality of microelectrodes (<NUM>) are mounted on the flexible framework and arranged in a plurality of groups;
wherein each group of the plurality of groups of microelectrodes (<NUM>) comprises a row of longitudinally-aligned microelectrodes aligned parallel to the catheter shaft longitudinal axis;
wherein the flexible array of microelectrodes (<NUM>) comprises a two-sided planar array of microelectrodes, wherein the microelectrodes are configured for contacting tissue on a front side and back side of the planar array; wherein the flexible framework comprises a plurality of longitudinally-extending and laterally separated arms (<NUM>, <NUM>, <NUM>, <NUM>) extending parallel to the catheter shaft longitudinal axis, and lying in a plane; wherein each longitudinally-extending arm (<NUM>, <NUM>, <NUM>, <NUM>) has a group of the plurality of groups of microelectrodes (<NUM>) distributed and located thereon; wherein a proximal bushing (<NUM>) is mounted on the distal end of the catheter shaft; wherein each longitudinally-extending arm exits from a distal end of the proximal bushing (<NUM>); and
wherein the plurality of longitudinally-extending arms (<NUM>, <NUM>, <NUM>, <NUM>) are configured to maintain the plurality of microelectrodes (<NUM>) in the plurality of rows in a spaced relationship such that each of the plurality of microelectrodes (<NUM>) can capture separate data about the electrical activity of cardiac tissue adjacent to the plurality of microelectrodes (<NUM>).