Medical probe with an interleaved microelectrode configuration

Abstract

The present invention discloses an electrophysiological catheter having a distal microelectrode assembly, the distal microelectrode assembly having a covered ridge carrying a plurality of microelectrodes. The microelectrode assembly includes a first ridge radiating away from the longitudinal axis and a second ridge adjacent to the first ridge and radiating away from the longitudinal axis, the first ridge having a plurality of first microelectrodes disposed thereon. The second ridge has a plurality of second microelectrodes disposed thereon such that a first virtual circle intersecting one of the plurality of first microelectrodes does not intersect any of the second microelectrodes.

Description

[0001] Priority

[0002] This application claims the benefit of priority as a partial continuation of U.S. Patent Application Serial No. 15 / 890318, filed on February 6, 2018, entitled "CATHETER WITH INCREASED ELECTRODE DENSITY SPINE ASSEMBLY HAVING REINFORCED SPINE COVERS," having Attorney Docket No. BIO5891USNP, pursuant to 35 U.S.C. § 120. The prior patent application is hereby incorporated by reference into this patent application as if fully set forth herein. BACKGROUND OF THE INVENTION

[0003] Electrode catheters have been commonly used in medical practice for many years. They are used to stimulate and map the electrical activity in the heart, as well as to ablate sites of abnormal electrical activity.

[0004] In use, a microelectrode catheter is inserted into a major vein or artery (e.g., the femoral artery) and then advanced into the chamber of the heart of interest. Once the catheter is positioned within the heart, the location of abnormal electrical activity within the heart is located.

[0005] One localization technique involves an electrophysiological mapping procedure whereby electrical signals emanating from conductive endocardial tissue are systematically monitored and a map is formed from these signals. By analyzing the map, a physician can identify interfering electrical pathways. A conventional method for mapping electrical signals from conductive cardiac tissue is to introduce an electrophysiological catheter (electrode catheter) through the skin, the electrophysiological catheter having mapping microelectrodes mounted on its distal end. The catheter is manipulated to place these microelectrodes in contact with the endocardium. By monitoring the electrical signals at the endocardium, sites of abnormal conductive tissue that cause arrhythmias can be identified.

[0006] For sensing via the annular microelectrodes mounted on the catheter, the leads that transmit signals from the annular microelectrodes are electrically connected to a suitable connector in the distal end of the catheter control handle, which is electrically connected to an ECG monitoring system and / or a suitable 3D electrophysiological (EP) mapping system, such as CARTO, CARTO XP, or CARTO 3, available from Biosense Webster, Inc. (Irwindale, California).

[0007] Relative to far-field signals, smaller and more closely spaced microelectrode pairs allow for more accurate detection of near-field electrical potentials, which can be very important when attempting to address specific regions of the heart. For example, near-field pulmonary vein electrical potentials are very small signals, while the atria located very close to the pulmonary veins provide much larger signals. Thus, even when a catheter is placed in the pulmonary vein region, it may still be difficult for an electrophysiologist to determine whether a signal is a small near potential (from the pulmonary vein) or a larger far potential (from the atria). Smaller and closely spaced bipolar electrodes allow a physician to more accurately remove far-field signals and obtain a more accurate reading of the electrical activity in local tissue. Thus, with smaller and more closely spaced microelectrodes, the location of myocardial tissue with pulmonary vein electrical potentials can be precisely targeted, and thus allows a clinician to deliver therapy to a specific tissue. In addition, smaller and more closely spaced microelectrodes allow a physician to determine the precise anatomical location of the cardiac ostium via electrical signals.

[0008] Increasing the microelectrode density (e.g., by increasing the number of microelectrodes carried on a catheter) also improves detection accuracy. However, the more microelectrodes carried on a catheter, especially the higher the microelectrode density, the greater the risk of microelectrode contact and short circuit. In addition, it is always desirable to improve the microelectrode-tissue contact with a highly flexible microelectrode assembly structure that can make reliable contact but in a manner that allows the microelectrode-bearing structure to operate in a controlled and predictable manner without piercing or damaging the tissue. As the materials used to construct these structures become more flexible and delicate, the risk of deformation, especially elongation, of the smaller annular microelectrodes and their support structures during catheter assembly increases. In addition, as the microelectrode assembly structure becomes more delicate, the risk of component separation, kinking, and entanglement increases.

[0009] Accordingly, there is a need for an electrophysiology catheter having closely spaced microelectrodes to achieve a high microelectrode density. There is also a need for an electrophysiology catheter having microelectrode-bearing structures that are delicate in construction to provide the desired flexibility but whose movement is predictable upon tissue contact. There is also a need for an electrophysiology catheter constructed in such a way as to minimize the risk of component separation, kinking, and entanglement and to enhance the ridge construction to minimize deformation (including elongation of the soft ridge cover and the microelectrodes carried thereon). Summary of the Invention

[0010] The present invention relates to an electrophysiological catheter having a distal microelectrode assembly that carries very small and closely spaced microelectrodes on a plurality of discrete ridges that are flexibly extensible over a tissue surface area to detect signals simultaneously at multiple locations while minimizing detection of unwanted noise, including far-field signals. The distal microelectrode assembly is configured to conform to the different anatomies of tissue in the atrial chamber of the heart. The ridges have curved segments or curved segments with straight segments to provide a wide range of adaptability to different tissue surfaces while providing mechanical advantages in different segments to improve flexibility and rigidity, thereby facilitating better contact with the tissue. Each ridge has a generally tapered configuration from its proximal end to its distal end to provide a more robust and rigid proximal base and a more flexible distal end to improve flexibility characteristics while minimizing the risk of the ridges touching or tangling.

[0011] In some embodiments, the electrophysiological catheter has an elongate body and a distal microelectrode assembly. The distal microelectrode assembly has a proximal stem, a plurality of ridges extending from the proximal stem, and a plurality of non-conductive ridge covers, each ridge cover surrounding a corresponding ridge, and each ridge cover having a plurality of tensile members embedded in the sidewall of the cover.

[0012] In some embodiments, the tensile members extend in the longitudinal direction.

[0013] In some embodiments, the tensile members have portions that extend in the longitudinal direction.

[0014] In some embodiments, the tensile members include wires.

[0015] In some embodiments, the tensile members include fibers.

[0016] In some embodiments, the electrophysiological catheter has an elongate body and a distal microelectrode assembly. The distal microelectrode assembly has a proximal stem and a plurality of ridges, each ridge having an enlarged distal portion that has a through-hole. The distal microelectrode assembly also has a plurality of non-conductive ridge covers, each ridge cover surrounding a corresponding ridge. The distal microelectrode assembly also has a cap cover that encapsulates the enlarged distal portion, and the cap cover has a portion that extends through the through-hole.

[0017] In some embodiments, the electrophysiological catheter has an elongate body and a distal microelectrode assembly. The distal microelectrode assembly has a proximal stem and a plurality of at least eight ridges, each ridge having a first segment and a linear segment, the first segment having a first preformed curvature defined by a first radius. The distal microelectrode assembly also has a plurality of non-conductive ridge covers and a plurality of microelectrodes, with at least one microelectrode on each ridge.

[0018] In some embodiments, each ridge includes a second segment having a second preformed curvature defined by a second radius different from the first radius, and the second segment having the second preformed curvature is distal to the first segment having the first preformed curvature.

[0019] In some embodiments, the first radius is less than the second radius.

[0020] In some embodiments, the second preformed curvature is opposite to the first preformed curvature.

[0021] In some embodiments, the second segment having the second preformed curvature is distal to the first segment having the first preformed curvature.

[0022] In some embodiments, a linear segment is located between the first segment having the first preformed curvature and the second segment having the second preformed curvature.

[0023] In some embodiments, the second segment having the linear segment is distal to the second segment having the second preformed curvature.

[0024] In some embodiments, each covered ridge has an outer perimeter of less than 3 French.

[0025] In some embodiments, the outer perimeter is about 2.6 French.

[0026] In some embodiments, an electrophysiological catheter has an elongate body and a distal microelectrode assembly. The distal microelectrode assembly has a proximal portion and a plurality of ridges, each ridge having a linear taper with a wider proximal end and a narrower distal end. The distal microelectrode assembly also has a plurality of non-conductive ridge covers, each non-conductive ridge cover surrounding a respective ridge.

[0027] In some embodiments, the linear taper is continuous.

[0028] In some embodiments, the linear taper is discontinuous.

[0029] In some embodiments, the discontinuous linear taper includes a recessed portion having a width less than the width of a more proximal stem and the width of a more distal portion.

[0030] In some embodiments, the ridge has a hinge along a lateral edge, and the hinge is configured for in-plane deflection of the ridge.

[0031] In some embodiments, the electrophysiology catheter has an elongate body and a distal microelectrode assembly. The distal microelectrode assembly has a proximal shaft, a plurality of ridges, the number of which is at least eight, and each ridge has a linear taper with a wider proximal end and a narrower distal end. The distal microelectrode assembly also has a plurality of non-conductive ridge covers, each non-conductive cover surrounding a corresponding ridge. The distal microelectrode assembly also has a plurality of microelectrodes, the plurality being at least about 48, and each microelectrode has a length of about 480 μm.

[0032] In some embodiments, the microelectrodes on each ridge are separated by a distance within a range of between about 1 mm and 3 mm as measured between the leading edges of the microelectrodes.

[0033] In some embodiments, the distance is about 2 mm.

[0034] In some embodiments, the microelectrodes on each ridge are arranged as bipolar pairs, wherein the leading edges of the microelectrodes within a pair are separated by a first distance within a range of between about 1 mm and 3 mm, and wherein the leading edges of the front microelectrodes between pairs are separated by a second distance within a range of between 1 mm and 6 mm.

[0035] In some embodiments, the first distance is about 2 mm and the second distance is about 6 mm.

[0036] In some embodiments, the plurality of microelectrodes is equal to about 64.

[0037] In some embodiments, the plurality of microelectrodes is equal to about 72.

[0038] In some embodiments, a first annular microelectrode is carried on the proximal shaft of the distal microelectrode assembly, and a second annular microelectrode and a third annular microelectrode are carried on the distal portion of the elongate body.

[0039] In some embodiments, the electrophysiology catheter has an elongate body and a distal microelectrode assembly. The distal microelectrode assembly has a proximal shaft that defines a perimeter about a longitudinal axis. The distal microelectrode assembly also has a plurality of ridges that emanate from the proximal shaft and diverge at their distal ends, the plurality of ridges alternating between a first ridge and a second ridge about the perimeter of the shaft. The distal microelectrode assembly also has a plurality of non-conductive ridge covers and a plurality of microelectrodes, each ridge cover surrounding a corresponding ridge, and the plurality of microelectrodes has a staggered configuration with respect to the first ridge and the second ridge, wherein the most proximal microelectrode on each first ridge is positioned at a greater distance from the proximal shaft, and the most proximal microelectrode on each second ridge is positioned at a smaller distance from the proximal shaft.

[0040] In some embodiments, the distal microelectrode assembly includes at least four first ridges and four second ridges, and each ridge carries eight microelectrodes.

[0041] In some embodiments, each microelectrode has a length of about 480 μm.

[0042] In some embodiments, the microelectrodes on each ridge are separated by a distance in the range of between about 1 mm and 3 mm as measured between the leading edges of the microelectrodes.

[0043] In some embodiments, the distance is about 2 mm.

[0044] In some embodiments, the microelectrodes on each ridge are arranged as bipolar pairs, wherein the leading edges of the microelectrodes within a pair are separated by a first distance in the range of between about 1 mm and 3 mm, and wherein the leading edges of the front microelectrodes between multiple pairs are separated by a second distance in the range of between 1 mm and 6 mm.

[0045] In some embodiments, the first distance is about 2 mm and the second distance is about 6 mm.

[0046] In some embodiments, the electrophysiology catheter has an elongate body and a distal microelectrode assembly. The distal microelectrode assembly has a proximal shaft having a sidewall with an inner surface defining a lumen and an opening in the sidewall. The distal microelectrode assembly also has a plurality of ridges extending from the proximal shaft and diverging at their distal ends, and a plurality of non-conductive covers, each non-conductive cover surrounding a respective ridge. The distal microelectrode assembly also has a plurality of microelectrodes on each ridge, and a housing insert received in the lumen of the shaft, the housing insert having an outer surface with a gap remaining between the outer surface and the inner surface of the shaft. An adhesive fills the gap between the inner surface of the proximal shaft and the outer surface of the housing insert, and the adhesive has a portion passing through the opening in the sidewall of the proximal shaft.

[0047] In some embodiments, the adhesive has a second layer that coats the outer surface of the shaft and seals the opening in the sidewall of the proximal shaft.

[0048] In some embodiments, the housing insert has a lumen with a cross-section having an elongate kidney-bean shape configuration.

[0049] In some embodiments, the housing insert has a lumen with a cross-section having a C-shaped configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings. It should be understood that certain structures and features are not shown in some of the drawings to provide a better view of the remaining structures and features.

[0051] Figure 1Perspective view of the catheter of the present invention according to one embodiment.

[0052] Figure 2 Is Figure 1 End cross-sectional view of the catheter body of the catheter.

[0053] Figure 3 Is Figure 1 End cross-sectional view of the deflection section of the catheter.

[0054] Figure 4 Perspective view of an integral support member according to one embodiment.

[0055] Figure 5A Side view of an integral support member according to one embodiment.

[0056] Figure 5B Is Figure 5A Detailed view of the integral support member.

[0057] Figure 5C Is taken along line C-C Figure 5A End cross-sectional view of the integral support member.

[0058] Figure 5D Is Figure 5A Detailed view of the enlarged distal portion of the ridge.

[0059] Figure 5E Is Figure 5A Detailed view of the end cross-sectional view of the ridge.

[0060] Figure 6A Side view of an integral support member according to one embodiment.

[0061] Figure 6B Is Figure 6A Detailed view of the integral support member.

[0062] Figure 6C Is Figure 6B Detailed view of the distal portion of the ridge.

[0063] Figure 6D Is Figure 6A Detailed view of the enlarged distal portion of the ridge.

[0064] Figure 6E Is taken along line E-E Figure 6B End cross-sectional view of the integral support member.

[0065] Figure 6F Is Figure 6B Detailed view of the end cross-sectional view of the proximal portion of the ridge.

[0066] Figure 6G is Figure 6B A detailed view of an end cross-sectional view of the distal portion of the ridge of

[0067] Figure 7A A side view of an integral support member according to one embodiment.

[0068] Figure 7B is Figure 7A A side view of the integral support member of , where the support member is in contact with tissue.

[0069] Figure 8A A side view of an integral support member according to another embodiment.

[0070] Figure 8B is Figure 8A A side view of the integral support member of , where the support member is in contact with tissue.

[0071] Figure 9A A side view of an integral support member according to another embodiment.

[0072] Figure 9B is Figure 9A A side view of the integral support member of , where the support member is in contact with tissue.

[0073] Figure 10 A side view of an integral support member according to one embodiment, shown to illustrate different parameters.

[0074] Figure 11A A top plan view of a ridge having a hinge structure according to one embodiment.

[0075] Figure 11B A top plan view of a ridge having a hinge structure according to another embodiment.

[0076] Figure 12A A side view of a covered ridge according to one embodiment.

[0077] Figure 12B A side view of a covered ridge according to another embodiment.

[0078] Figure 13A A front view of a distal microelectrode assembly according to one embodiment.

[0079] Figure 13B Shown in side view is Figure 13A the assembly of , which abuts a flat surface.

[0080] Figure 13C or Figure 13E shows along a direction parallel to Figure 13BObserved along the longitudinal axis orthogonal to the flat surface T Figure 13A Views of two variants of the component.

[0081] Figure 13D Shows Figure 13C The case where the ridges of the component are compressed into a collinear configuration.

[0082] Figure 13F Shows Figure 13C Variants on the component.

[0083] Figure 13G 、 Figure 13H And Figure 13I Shows Figure 13C More variants of the component.

[0084] Figure 13J Shows a cross-sectional view of an exemplary electrode relative to a ridge to show the eccentric or laterally offset configuration of each electrode on a ridge.

[0085] Figure 14A Is a side cross-sectional view of the junction between the deflection segment and the distal microelectrode assembly according to one embodiment.

[0086] Figure 14B Is Figure 14A An end cross-sectional view of the housing insert.

[0087] Figure 15A Is a side cross-sectional view of the junction between the deflection segment and the distal microelectrode assembly according to another embodiment.

[0088] Figure 15B Is Figure 15A An end cross-sectional view of the housing insert.

[0089] Figure 16 Is a side perspective view of a covered ridge with an enhanced tensile member according to one embodiment.

[0090] Figure 17 Is a detailed side cross-sectional view of a portion of the junction with an enhanced tensile member according to one embodiment.

[0091] Figure 18 Is an end cross-sectional view of a housing insert with an enhanced tensile member passing through it according to one embodiment.

[0092] Figure 19 Is an end cross-sectional view of a deflection segment with an enhanced tensile member passing through it according to one embodiment.

[0093] Figure 20 Is an end cross-sectional view of a catheter body with an enhanced tensile member passing through it according to one embodiment.

[0094] Figure 21 Schematic diagrams of the placement of the heart and the catheter of the present invention for tissue contact according to various embodiments.

[0095] Figure 22 Schematic diagram of a distal microelectrode assembly in contact with tissue in a pulmonary vein according to one embodiment.

[0096] Figure 23 Schematic diagram of a distal microelectrode assembly in contact with tissue on the side wall of the heart according to one embodiment.

[0097] Figure 24 Schematic diagram of a distal microelectrode assembly in contact with tissue on the inferior wall or apex of the heart according to one embodiment.

[0098] Figure 25 Taken along line A - A Figure 15A End cross-sectional view of the distal end of the distal microelectrode assembly. DETAILED DESCRIPTION

[0099] The following detailed description should be read in conjunction with the accompanying drawings, in which like numerals in different drawings refer to like elements. The drawings (not necessarily to scale) illustrate selected embodiments and are not intended to limit the scope of the invention. The detailed description shows, by way of example and not limitation, the principles of the invention. This description will clearly enable those skilled in the art to make and use the invention, and describes several embodiments, adaptations, variations, alternatives, and uses of the invention, including what is presently believed to be the best mode of carrying out the invention.

[0100] As used herein, the term "about" or "approximately" in reference to any numerical value or range indicates a suitable dimensional tolerance that allows a set of components or elements to achieve its intended purpose as described herein. More specifically, "about" or "approximately" can refer to a range of values ±10% of the recited value, e.g., "about 90%" can refer to a range of values from 81% to 99%. Additionally, as used herein, the terms "patient", "host", "user", and "subject" refer to any human or animal subject, and are not intended to limit the system or method to human use, but the use of the subject invention in human patients represents a preferred embodiment. Similarly, the term "proximal" refers to a position closer to the operator, while "distal" refers to a position farther from the operator or physician.

[0101] See Figure 1 , in some embodiments of the present invention, the catheter 10 includes a catheter body 12, an intermediate deflection section 14, a distal microelectrode assembly 15, and a control handle 16 located proximal to the catheter body 12. The distal microelectrode assembly 15 includes a plurality of ridges 17, each of which supports a plurality of microelectrodes 18.

[0102] In some embodiments, the catheter body 12 includes an elongated tubular structure having a single axial lumen or central lumen 19, as Figure 2 shown. The catheter body 12 is flexible, i.e., bendable, but substantially non-compressible along its length. The catheter body 12 can have any suitable configuration and can be made of any suitable material. Currently preferred configurations include an outer wall 20 made of polyurethane or PEBAX. The outer wall 20 includes an embedded braided mesh made of high-strength steel, stainless steel, etc., to increase the torsional stiffness of the catheter body 12 such that when the control handle 16 is rotated, the deflection section 14 of the catheter 10 rotates in a corresponding manner.

[0103] The outer diameter of the catheter body 12 is not a critical factor. Similarly, the thickness of the outer wall 20 is not a critical factor, but is thin enough such that the central lumen 19 can accommodate components including, for example, one or more pull wires, microelectrode leads, irrigation tubes, and any other wires and / or cables. In some embodiments, the inner surface of the outer wall 20 is lined with a rigid tube 21, which can be made of any suitable material such as polyimide or nylon. The rigid tube 21, together with the braided outer wall 20, provides improved torsional stability while minimizing the wall thickness of the catheter and thus maximizing the diameter of the central lumen 19. As will be appreciated by those skilled in the art, the catheter body configuration can be modified as needed. For example, the rigid tube can be removed.

[0104] In some embodiments, the intermediate deflection section includes a shorter section of tube 30, as Figure 3 shown, which has a plurality of lumens 31. In some embodiments, the tube 30 is made of a suitable biocompatible material that is more flexible than the catheter body 12. A suitable material for the tube 19 is braided polyurethane, i.e., polyurethane having an embedded mesh of braided high-strength steel, stainless steel, etc. The outer diameter of the deflection section 14 is similar to the outer diameter of the catheter body 12. The number and size of the lumens are not critical factors and can vary depending on the specific application.

[0105] Various components extend through the catheter 10. In some embodiments, these components include leads 22 for the distal microelectrode assembly 15, one or more pull wires 23A and 23B for deflecting the deflection section 14, and a cable 24 for an electromagnetic position sensor 26 (see Figure 14A and Figure 15A ) to be received at or near the distal end of the deflection section 14. In some embodiments, the catheter includes an irrigation tube 27 for delivering fluid to the distal end of the deflection section 14. These components pass through the central lumen 19 of the catheter body 12, as Figure 2 shown.

[0106] In the deflection section 14, different components pass through different lumens 31 of the tube 30, such as Figure 3 In some embodiments, the lead 22 passes through one or more lumens 31A, the first puller wire 23A passes through the lumen 31B, the cable 24 passes through the lumen 31C, the second puller wire 23B passes through the lumen 31D, and the irrigation tube 27 passes through the lumen 31E. Lumen 31B and lumen 31D are diametrically opposed to each other to provide bidirectional deflection of the intermediate deflection segment 14. Additional components can pass through additional lumens or share lumens with other aforementioned components as needed.

[0107] Distal to the deflection segment 14 is a distal microelectrode assembly 15, which includes Figure 4 The one-piece support member 40 shown. In some embodiments, the one-piece support member 40 includes a superelastic material with shape memory, that is, a superelastic material that can temporarily straighten or bend from its original shape when a force is applied, and can substantially return to its original shape when there is no force or the force is removed. One material suitable for the support member is a nickel / titanium alloy. Such alloys typically contain about 55% nickel and 45% titanium, but can also contain about 54% to about 57% nickel, with the remainder being titanium. The nickel / titanium alloy is nitinol, which has excellent shape memory as well as ductility, strength, corrosion resistance, resistivity, and temperature stability.

[0108] In some embodiments, the member 40 is constructed and formed from an elongated hollow cylindrical member that has, for example, portions cut (e.g., by laser cutting) or otherwise removed to form an elongated body of a proximal portion or stem 42 and a spine 17 that emanates longitudinally from the stem and spans outwardly from the stem. The stem 42 defines a lumen 43 therethrough for receiving a distal end portion 30D of the multi-lumen tube 30 of the deflection segment 14 (see Figure 14A ), as well as various components as further discussed below, which are housed in the rod 42 or extend through the tubular cavity 43.

[0109] Each ridge 17 of the member 40 has an enlarged distal portion 46, and each ridge has a wider proximal end and a narrower distal end. Figure 5A , Figure 5B , Figure 5C , Figure 5D and Figure 5E As shown, the spine is linearly tapered to achieve an "out-of-plane" flexibility that varies along its length (see Figure 5E In some embodiments, one or more ridges 17 have a proximal portion 17P having a uniform width W1, a distal portion 17D1 having a continuous linear taper defined by a taper line T1 (see FIG. Figure 5B), and a more distal portion 17D2 having a uniform width W2 that is less than W1. The distal portion 17D1 has a continuously increasing flexibility such that when the distal portion 46 contacts tissue, the ridges can adopt a predetermined form or curvature. The resulting ridges with a relatively more rigid proximal portion and a relatively more flexible distal portion help prevent the ridges from crossing and overlapping each other during use.

[0110] In some embodiments, one or more ridges 17 have a discontinuous linear taper between the end 41 and the end 46, as Figure 6A , Figure 6B , Figure 6C , Figure 6D , Figure 6E , Figure 6F and Figure 6G shown. The discontinuous linear taper includes one or more narrower or recessed portions 50 that are strategically located along the ridge to interrupt other continuous linear tapers defined by the taper T2 between the rod 42 and the enlarged distal portion 46. Each recessed portion 50 has a width W (see Figure 6C ), which is less than the width WD of the more distal portion and also less than the width WP of the more proximal portion, where width WD < width WP. Thus, each recessed portion 50 advantageously allows this region of the ridge to have a different flexibility from the immediately adjacent (distal and proximal) portions 51 of the ridge and provides a degree of independent flexibility between the portions separated by the recessed portion 50 (see Figure 6B ). Thus, when the distal portion 46 contacts tissue, the ridges are allowed to exhibit significantly greater flexibility in this region of the recessed portion 50 relative to the portions 51 of the ridge and thus exhibit a tighter or sharper curvature.

[0111] In some embodiments, each ridge (between the distal end of the rod 42 and the distal end of the ridge) has a length in the range of between about 1.0 cm and 2.5 cm, or between about 1.50 cm and 2.0 cm, and a width in the range of between about 0.009 inches and 0.02 inches. In some embodiments, the recessed portion 50 has a length in the range of between about 10% and 20% of the length of the ridge, and a width W in the range of between about 50% and 80% of the adjacent width, measured from the distal end of the rod 42, and the proximal leading edge of the recessed portion is located at about 55% to 65% of the length of the ridge.

[0112] To further facilitate contact of the microelectrodes with tissue along the entire length of the ridge, each ridge 17 has a preformed configuration or curvature that is achieved, for example, by heating and molding a fixture. One or more ridges 17 have at least two different preformed curvatures C1 and C2, as Figure 7AAs shown, a section S1 having a preformed curvature C1 is defined by a radius R1, and a section S2 having a preformed curvature C2 is defined by a radius R2, where the radius R1 < R2 and the curvatures C1 and C2 are generally in opposite directions from each other, such that the ridge of the one-piece support member 40 has a generally forward-facing concave surface similar to an open umbrella. As Figure 7B shown (only two ridges are shown for clarity), when the distal ends of the ridges contact an exemplary surface SF, the preformed ridges transition from their neutral configuration N (shown in dashed lines) to their conforming or temporary "deformed" configuration A, which can include a "crouched" profile (compared to their neutral configuration) having undulating regions that may be more suitable for cardiac tissue. Advantageously, the one-piece support member 40 maintains its generally forward-facing concave configuration without turning itself inside out upon tissue contact (like an umbrella flipping inside out in strong wind).

[0113] In some embodiments, one or more ridges 17 have at least a curved section and a linear section. In some embodiments, one or more ridges have at least two different preformed curvatures along their length. For example, as Figure 8A shown, one or more ridges 17 have a first section SA, a second section SB, and a third section SC, where the first section SA has a preformed curvature CA defined by a radius RA, the second section SB has a preformed curvature CB defined by a radius RB, and the third section SC is linear, where the radius RA < the radius RB. As Figure 8B shown (only two ridges are shown for clarity), when the distal ends of the ridges contact an exemplary surface SF, the preformed ridges transition from their neutral configuration N to their conforming or temporary "deformed" configuration A, which can include a deeper concave surface (compared to their neutral configuration) having convex regions that may be more suitable for cardiac tissue.

[0114] As another example, as Figure 9A shown, one or more ridges 17D have a first section SJ, a second section SK, and a third section SL, where the first section SJ has a preformed curvature CJ defined by a radius RJ, the second section SK is linear, and the third section SL has a preformed curvature CL defined by a radius RL, where the radius RJ < the radius RL. As Figure 9B shown (only two ridges are shown for clarity), when the distal ends of the ridges contact an exemplary surface SF, the preformed ridges transition from their neutral configuration N to their conforming or temporary "deformed" configuration A, which can include a lower profile (compared to their neutral configuration) having flatter regions that may be more suitable for cardiac tissue.

[0115] Refer to Figure 10, in some embodiments, the one-piece support member 40 and its ridge 17 can be defined by a plurality of parameters, including, for example, the following parameters:

[0116] a = the height of the second curvature, in the range between about 0.00 inches and 0.050 inches

[0117] b = the distal length of the second curvature, in the range between about 0.302 inches and 0.694 inches

[0118] c = the proximal length of the second curvature, in the range between about 0.00 inches and 0.302 inches

[0119] d = the distance between the first curvature and the second curvature, in the range between about 0.00 inches and 0.170 inches

[0120] e = the first radius of curvature, in the range between about 0.075 inches and 0.100 inches

[0121] f = the length of the section with a uniform width, about 0.100 inches

[0122] g = the depth of the concave surface, in the range between about 0.123 inches and 0.590 inches

[0123] It should be noted that in some embodiments of the one-piece support member 40, the proximal (or first) preformed curvature is opposite to the distal (or second) preformed curvature, such that the ridge 17 of the distal microelectrode assembly 15 can maintain its generally concave surface and remain facing forward when in contact with tissue without inverting, while the highly flexible ridge allows the assembly to be flexible or "stretchable", which prevents the distal tip of the ridge from piercing the tissue or otherwise damaging the tissue when contacting the tissue and when the distal microelectrode assembly is pressed against the tissue surface to ensure contact with the tissue by each of the ridges 17. Additionally, in some embodiments, the recessed portion 50 can span between the proximal preformed curvature and the distal preformed curvature, such that each of the three portions of the ridge (proximal portion, recessed portion, and distal portion) can behave differently in response to tissue contact and the associated pressure applied by the operating user of the catheter and have a degree of independence from each other in terms of flexibility.

[0124] It should be understood that for ease of discussion and explanation, the foregoing figures show exaggerated deformations and curvatures of the ridge, and the actual deformations and curvatures may be much more subtle and less acute.

[0125] In some embodiments, one or more of the ridges 17 are also configured to have a hinge 90 for in-plane (from side to side) deflection. As Figure 11A and Figure 11BAs shown, the ridge 17 may have a plurality of notches or grooves along opposite lateral edges, including an inflatable groove 80 (e.g., in the form of slits 81 and circular openings 82) along one edge 85a and a compressible groove 83 (e.g., in the form of slots 84 and circular openings 82) along the opposite edge 85b, thereby forming a hinge 90 for more in-plane deflection along these edges. In Figure 11A and Figure 11B embodiments, unidirectional deflection occurs towards the edge 85b of the ridge 17. However, it should be understood that in the case where compressible grooves 83 are formed along both the edge 85a and the edge 85b, the ridge 17 has bidirectional deflection towards either the edge 85a or the edge 85b. Suitable hinges are described in U.S. Patent No. 7276062, the entire content of which is incorporated herein by reference.

[0126] As Figure 12A and Figure 12B shown, each ridge 17 of the distal microelectrode assembly 15 is surrounded along its length by a non-conductive ridge covering or tube 28. In some embodiments, the non-conductive ridge covering 28 comprises a very soft and highly flexible biocompatible plastic, such as PEBAX or PELLATHANE, and the ridge covering 28 is mounted on the ridge and extends together with the ridge between the shaft 42 and the enlarged distal portion 46. The suitable construction material of the ridge covering 28 is soft and flexible enough so as not to generally impede the flexibility of the ridge 17.

[0127] In some embodiments, each covered ridge 17 has a diameter D of less than 3 French along its length, preferably less than 2.7 French, and more preferably a diameter of 2 French (e.g., a diameter between about 0.025 inches and 0.035 inches).

[0128] Each ridge 17 includes a non-traumatic distal covering or cap 45 that encapsulates the enlarged distal portion 46 (see Figure 12A ). In some embodiments, the covering 45 comprises a biocompatible adhesive or sealant, such as polyurethane, which has a bulbous configuration to minimize damage to tissue when contacting tissue or applying pressure against tissue. The construction of the covering 45 includes a bridging portion 63 of the adhesive or sealant that passes through a through-hole 47 in the enlarged distal portion 46 and advantageously forms a mechanical lock that secures the covering 45 to the distal portion 46 and minimizes the risk of separation of the covering 45 from the enlarged distal portion 46.

[0129] Each ridge 17 carries a plurality of microelectrodes 18. The number and arrangement of the microelectrodes can vary according to the intended use. In some embodiments, the "plurality" is in the range of between about 48 and 72, but it should be understood that the "plurality" can be larger or smaller. In some embodiments, each microelectrode has a length L of less than 800 μm (e.g., in the range of between about 600 μm and 300 μm, and for example, measured to be about 480 μm, 460 μm, or about 450 μm). In some embodiments, the distal microelectrode assembly 15 has an area coverage greater than about 7.1 / cm 2 (e.g., in the range of between about 7.2 / cm 2 and 12.6 / cm 2 ). In some embodiments, the distal microelectrode assembly 15 has a microelectrode density greater than about 2.5 microelectrodes / cm 2 (e.g., in the range of between about 4 microelectrodes / cm 2 and 7 microelectrodes / cm 2 ).

[0130] In some embodiments, the distal microelectrode assembly 15 has eight ridges, each ridge having a length of about 1.5 cm and carrying eight microelectrodes, for a total of 48 microelectrodes. Each microelectrode on each ridge has a length of about 460 μm, where the assembly 15 has an area coverage of about 7.1 / cm 2 , and a microelectrode density of about 7 microelectrodes / cm 2 .

[0131] In some embodiments, the distal microelectrode assembly 15 has eight ridges, each ridge having a length of about 2.0 cm and carrying six microelectrodes, for a total of 48 microelectrodes. Each microelectrode on each ridge has a length of about 460 μm, where the assembly 15 has an area coverage of about 12.6 / cm 2 , and a microelectrode density of about 4 microelectrodes / cm 2 .

[0132] The microelectrodes 18 on the ridge 17 can be arranged as monopolar or bipolar with various spacings therebetween, where the spacing is measured as the interval between the corresponding leading edges of adjacent microelectrodes or microelectrode pairs. As monopolar, the microelectrodes 18 can be separated by a distance S1 in the range of between about 1 mm and 3 mm, refer to Figure 12A . As bipolar, adjacent pairs of microelectrodes 18 can be separated by a distance S2 in the range of between 1 mm and 6 mm, refer to Figure 12B .

[0133] In some embodiments, refer to Figure 12B, six microelectrodes are arranged as three bipolar pairs, the spacing S1 between the proximal edges of the bipolar pairs is 2.0 mm, and the spacing S2 between the proximal edges of adjacent bipolar pairs is 6.0 mm. These three bipolar pairs can generally be referred to as the "2-6-2" configuration. Another configuration, called the "2-5-2-5-2" configuration, has three bipolar pairs, where the spacing S1 between the proximal edges of the bipolar pairs is 2.0 mm, and the spacing S2 between the proximal edges of adjacent bipolar pairs is 5.0 mm.

[0134] In some embodiments, referring to Figure 12A , six microelectrodes are arranged as monopoles, where the spacing S1 between the proximal edges of adjacent monopoles is 2.0 mm. The monopoles can be referred to as the "2-2-2-2-2" configuration. In some embodiments, the spacing S1 is about 3.0 mm and is thus referred to as the "3-3-3-3-3" configuration.

[0135] In some embodiments, the most proximal microelectrode 18P of each ridge is carried at a location on the ridge different from the most proximal microelectrode 18P of an adjacent ridge. As shown in the end effector 400 of Figure 13A , although the spacing between the microelectrodes on any one ridge can be uniform throughout the distal microelectrode assembly, the microelectrodes along any one ridge are staggered with respect to the microelectrodes along an adjacent ridge. For example, for ridges 17A, 17C, 17E, and 17G, the distance D1 between the most proximal microelectrode 18P and the end of the shaft 42 is greater than the distance D2 between the most proximal microelectrode 18P and the end of the shaft 42 for ridges 17B, 17D, 17F, and 17H. This staggered configuration minimizes the risk of the microelectrodes on adjacent ridges touching and shorting, especially when the operator sweeps the distal microelectrode assembly against tissue.

[0136] The construction of the junction between the distal microelectrode assembly and the distal portion of the deflection section 14 and the components of the assembly are described in U.S. Patent Nos. 7,089,045, 7,155,270, 7,228,164, and 7,302,285, the entire disclosures of which are incorporated herein by reference.

[0137] Figure 13B The end effector assembly 400 is shown in a side view Figure 13A where the ridges of the assembly are in contact with a flat surface T. In this configuration, the longitudinal axis L-L (defined by the shaft 42) is generally orthogonal to the flat surface T. It can be seen that the shaft 42 includes a tubular member 27, where the reference microelectrode 67A can be mounted in the distal portion of the tube member 27 with a clearance G to avoid contact with the tissue represented by the surface T.

[0138] We have recognized that in certain use cases, the microelectrodes of adjacent ridges can contact each other. Therefore, we have designed the placement of the microelectrodes on each ridge to ensure that the microelectrodes of adjacent ridges do not contact each other. Specifically, in Figure 13B it can be seen that there are eight ridges 17A, 17B, 17C, 17D, 17E, 17F, 17G, 17H, and each ridge has its corresponding six microelectrodes 17A1 - 17A6; 17B1 - 17B6; 17C1 - 17C6; 17D1 - 17D6; 17E1 - 17E6; 17F1 - 17F6; 17G1 - 17G6; 17H1 - 17H6 mounted on each of the respective ridges 17A, 17B, 17C, 17D, 17E, 17F, 17G, 17H. Using ridge 17A as a reference, it can be seen that when the end effector 400 is placed against a flat transparent surface (e.g., glass), the microelectrodes on ridge 17A can define various virtual circles with reference to the longitudinal axis L-L (or tube 27). For example, the first microelectrode 17A1 defines the first virtual circle VC1; the second microelectrode 17A2 defines the second virtual circle VC2; the third microelectrode 17A3 defines the third virtual circle VC3; the fourth microelectrode 17A4 defines the fourth virtual circle VC4; the fifth microelectrode 17A5 defines the fifth virtual circle VC5; the sixth microelectrode 17A6 defines the sixth virtual circle VC6, and so on for more microelectrodes on ridge 17A. The virtual circles demonstrate a "staggered" arrangement of the microelectrodes on one ridge relative to the microelectrodes on its adjacent ridges. As used herein, staggered indicates that a microelectrode on a reference ridge does not contact a different microelectrode on an adjacent ridge. In Figure 13C it can be seen that even if the reference ridge 17A can be rotated 45 degrees clockwise around the axis L-L towards ridge 17B, none of the microelectrodes 17A1, 17A2, 17A3, 17A4, 17A5, or 17A6 can contact the microelectrodes 17B1 - 17B6 of ridge 17B. Similarly, even if ridge 17A can be rotated 45 degrees counterclockwise around the axis L-L in Figure 13C none of the microelectrodes 17A1 - 17A6 can contact the microelectrodes 17H1 - 17H6 of ridge 17H.

[0139] Likewise, in the case where the ridges are compressed together by tissue such that the ridges are compressed in a collinear manner with the axis L-L, the microelectrodes of one ridge also cannot contact the microelectrodes of its adjacent ridges. This is shown in Figure 13Dis shown by way of example, where ridge 17A is compressed to be collinear with ridges 17H, 17G, 17F, and 17E. The stagger distance Dstagger1 between the leading edges of the corresponding microelectrodes 17A1 and 17H1 can be seen. Although the stagger distance between each of the microelectrodes 17A1 - 17A6 on ridge 17A and its corresponding adjacent microelectrodes 17H1 - 17H6 on the adjacent ridge 17H can be the same, other stagger distances can be utilized, such as, for example, the stagger distance Dstagger4 between the fourth microelectrodes 17A4 and 17H4 on the corresponding adjacent ridges 17A and 17H. The stagger distance can be any distance from about 0.1 mm to about 6 mm.

[0140] Referring again to Figure 13C , it can be seen that the microelectrodes on each ridge are configured to have the same gap distance D1 = D2 = D3 = D4 = D5 between the microelectrodes on each ridge. The gap distance can be measured at the leading edge of each microelectrode or from the center to center of each microelectrode. Although the gap distances are the same, the group of microelectrodes 1 - 6 on each ridge (e.g., 17A) is offset by the same stagger distance Dstagger1 from the group of microelectrodes 1 - 6 on the adjacent ridges (e.g., 17H and 17B). Figure 13E An embodiment is shown where the gap distances are not the same value and can be different. For example, gap distance D1 is less than gap distance D2 and can be equal to gap distances D3 and D5, while gap distance D4 can be equal to gap distance D2. As long as the group of microelectrodes on each ridge (e.g., 17A) is offset or staggered (e.g., Dstagger1) from its adjacent ridges (e.g., 17H and 17B), the gap distances D1, D2, D3, D4, and D5 can be unequal.

[0141] Although Figures 13A to 13E the configuration shown in the embodiment of Figure 13F is for a radial configuration using ridges with free ends, the same principle for the radial configuration can be applied to a closed - end ridge configuration that defines a basket - like member such as Figure 13F the basket - like member shown. Specifically, in

[0142] there are ridges 17A - 17L joined to a common center 270 to define a basket - shaped assembly. Each ridge can have a plurality of microelectrodes. For example, microelectrodes 17A1 - 1710 are arranged such that a virtual circle intersecting one of the microelectrodes 17A1 - 17A10 does not intersect the microelectrodes on the adjacent ridges (e.g., 17L or 17B).

[0142] Similarly, the same principles of these embodiments can be applied to the ridge arrays in the planar configurations (instead of the conical configuration of Figure 13G ), Figure 13H and Figure 13I shown herein. Figures 13A to 13E of

[0143] In Figures 13G to 13H these embodiments, the same naming convention is followed as for the previous posts 42 and ridges 170A, 170B, 170C, 170D, which are arranged to lie in a single plane ( Figure 13G and Figure 13H ) or multiple planes ( Figure 13I ). Each of the ridges 170A, 170B, 170C and 170D has microelectrodes 170A1 - 170A6; 170B1 - 170B6; 170C1 - 170C6; and 170D1 - 170D6. The microelectrode groups 170A1 - 170A6 are staggered or offset from the adjacent microelectrode groups 170B1 - 170B6 on the adjacent ridge 170B. The microelectrode groups 170B1 - 170B6 are offset from both the adjacent microelectrode groups 170A1 - 170A6 and 170C1 - 170C6. The end probe assembly 400 (which includes at least the ridges and the microelectrode groups for each ridge) can be constructed as shown in Figure 13G and Figure 13H such that the ridges are adjacent to a single contact plane. In Figure 13H , the ridge 170A can be connected to the ridge 170D using the connector 170AD, and the ridge 170B is connected to the ridge 170C using the connector 170BC. Contacts in more than one plane can be used with the configuration of Figure 13I , whereby the ridge 170A is connected to the ridge 170C via the connector 17AC to define a first contact plane for the microelectrode groups of these ridges, and the ridges 170B and 170D are connected using the connector 170BD to define a second contact plane.

[0144] It should be noted that the embodiments of Figures 13A to 13F , Figure 13H and Figure 13I show the electrodes of one ridge staggered or offset along the longitudinal axis L - L (of each ridge) relative to the electrodes on the adjacent ridges, and the center line or centroid L - L of each electrode A1 coincides with the longitudinal axis L - L of each ridge. We have also devised another staggered configuration where the center line of each electrode on one ridge is eccentrically offset from the longitudinal axis in the first direction T1 of the ridge on which it is mounted. This eccentric offset feature can be seen in Figure 13G and is also visible in Figure 13J , where the center line L - L of the electrode 170A1 A1 is offset by an eccentric distance "e" in a generally transverse direction T1 relative to the axis L - L of the ridge 170A. Similarly, the electrode 170B1 on the ridge 170B of Figure 13G is eccentrically offset in a generally opposite transverse direction T2 relative to the electrode 170A1 on the ridge 170A. It is contemplated that the electrodes on one ridge can be individually longitudinally offset relative to their adjacent electrodes on the adjacent ridges (Figures 13A to 13F , Figure 13H and Figure 13I ); staggered separately and eccentrically ( Figure 13J ) or simultaneously longitudinally and eccentrically, as Figure 13G shown.

[0145] Generally speaking, we have designed certain common features for the Figures 13A to 13J embodiments. Specifically, the various embodiments of the medical probe at least include the following features: an elongate member 14 that extends along a longitudinal axis, wherein a distal microelectrode assembly 400 is coupled to the elongate member 14; a proximal stem 42 that extends along the longitudinal axis L-L; a first ridge (e.g., 17A or 170A) that radiates away from the longitudinal axis L-L, the first ridge (e.g., 17A or 170A) having a plurality of first microelectrodes (17A1-17A6 or 170A1-170A6) disposed on the first ridge (17A or 170A); a second ridge (17B or 170B) that is adjacent to the first ridge (17A or 170A) and radiates away from the longitudinal axis L-L, the second ridge (e.g., 17B or 170B) having a plurality of second microelectrodes (17B1-17B6 or 170B1-170B6) disposed on the second ridge, such that a first virtual circle (e.g., VC1 or VC2) that intersects one of the plurality of first microelectrodes does not intersect any of the second microelectrodes. In another refinement, a third ridge may be provided that is adjacent to the first ridge and radiates away from the longitudinal axis. The third ridge has a plurality of third microelectrodes disposed on the third ridge, such that a first virtual circle that intersects one of the plurality of first microelectrodes does not intersect any of the second and third microelectrodes. Note that the first virtual circle is generally centered on the longitudinal axis and may be generally orthogonal to the longitudinal axis. To define the configuration of the ridges, the proximal stem may be arranged to be generally orthogonal to a flat surface, wherein the first, second, and third ridges contact the flat surface to define the radiation configuration of the ridges. The plurality of ridges may include five to eight or more ridges arranged in an equiangular configuration about the longitudinal axis.

[0146] Other common features of the embodiments include a plurality of ridges 17A, 17B, 17C, 17D, 17E... 17N extending along a longitudinal axis, wherein a plurality of first microelectrodes (17A1 - 17A6) are disposed on the first ridge 17A, and a plurality of second microelectrodes (17H1 - 17H6) are disposed on a second ridge (17H) adjacent to the first ridge (17A). The plurality of first microelectrodes (17A1 - 17A6) are spaced apart along the first ridge such that the first microelectrodes are offset by a stagger distance Dstagger1 relative to the second microelectrodes (17H1 - 17H2). In another refinement, a plurality of third microelectrodes are disposed on a third ridge adjacent to the first ridge such that the first microelectrodes are offset by the stagger distance Dstagger1 relative to the second and third microelectrodes. The stagger distance includes any distance from about 0.1 mm to about 5 mm measured between the leading edge of one microelectrode on one ridge and the leading edge of the nearest microelectrode on an adjacent ridge.

[0147] As Figure 14A shown, the rod 42 of the one-piece support member 40 receives the narrowed distal end 30D of the multi-lumen tube 30 of the deflection segment 14. A non-conductive sleeve 68 circumferentially surrounds the rod 42 and co-extends with the rod between the proximal and distal ends of the rod. The distal end 68D of the sleeve 68 extends over the proximal end 28P of the non-conductive ridge tube 28 to assist in securing the tube 28 to the ridge 17.

[0148] Proximal to the distal end 30D is a housing insert 60, which is also received and positioned within the lumen 43 of the rod 42 of the one-piece support member 40. The housing insert 60 is shorter in length in the longitudinal direction than the rod 42 such that the housing insert does not protrude beyond the distal end of the rod 42. The housing insert 60 is configured to have one or more lumens. One lumen 71 can have a non-circular cross-section, e.g., generally similar to the cross-section of a "C" or an elongated kidney bean, and another lumen 72 can have a circular cross-section, as Figure 14B shown, such that the lumens can be nested within each other to maximize the size of the lumens and increase the space efficiency within the housing insert 60. Components passing through the more lumen 71 are not restricted to any one position or orientation and thus have greater freedom of movement and a lower risk of breakage, especially when a section of the catheter is twisted and the components are distorted.

[0149] In some embodiments, an electromagnetic position sensor 26 (at the distal end of cable 24) is received within lumen 72. Other components, such as irrigation tube 27 and leads 22 for microelectrodes 18 on distal microelectrode assembly 15 (and leads 25 for any annular microelectrodes 67, 69, and 70 proximal to ridge 17), pass through lumen 71. In this regard, housing insert 60 provides multiple functions, including aligning and positioning various components within shaft 42 of integral support member 40; providing spacing for and separation between these various components, and serving as a mechanical lock that enhances the junction between the distal end of deflection segment 14 and distal microelectrode assembly 15. In the latter case, during assembly and use of the catheter, the junction may be subjected to various forces that may twist or pull on the junction. For example, a twisting force may clamp irrigation tube 27 to block flow, or cause leads 22 and 25 to break. To this end, the junction is advantageously assembled with housing insert 60 in a configuration to form a mechanical lock, as explained below.

[0150] Housing insert 60 may be selectively configured to have an outer diameter that is a predetermined amount smaller than the inner circumference of lumen 43 of shaft 42. This creates a perceptible void within lumen 43 that is filled with a suitable adhesive 61, such as polyurethane, to securely attach housing insert 60 within the interior of lumen 43 and to the distal end of multi-lumen tube 30, so as to minimize, if not prevent, relative movement between insert 60 and shaft 42. Housing insert 60 protects the components it surrounds, including electromagnetic position sensor 26 (and its attachment to cable 24), irrigation tube 27, and leads 22 and 25, and provides a larger and more rigid structure to which shaft 42 attaches. To this end, housing insert 60 may even have a non-circular / polygonal outer cross-section and / or a textured surface to improve the attachment between housing insert 60 and adhesive 61.

[0151] To facilitate application of the adhesive into the void, shaft 42 is formed with an opening 65 in its sidewall at a location that allows visual and mechanical access to the housing insert 60 after it has been inserted into lumen 43 of shaft 42. During assembly of the junction, visual inspection of lumen 43 and the components therein is provided through opening 65. Although any adhesive applied to the outer surface of housing insert 60 prior to insertion into lumen 43 may be ejected from shaft 42 during insertion, additional adhesive may be advantageously applied through opening 65 into lumen 43 to fill the void and thus securely attach housing insert 60 to shaft 42 and the distal portion of multi-lumen tube 30. The combination of housing insert 60 and its space accommodating lumen 71 provides a more integrated and less vulnerable junction between distal microelectrode assembly 15 and deflection segment 14.

[0152] In some embodiments, catheter 10 includes a flush tube 27, the distal end 27D of which generally coextends with the distal end of shaft 42 of the integral support member 40. Thus, flush fluid (such as saline) is delivered from a remote fluid source to the distal microelectrode assembly 15, the remote fluid source being via a Luer interface 100( Figure 1 ) that provides flush fluid via a flush tube 27 extending through the control handle 16, the central lumen 19 of the catheter body 12( Figure 2 ) and the lumen 31E of tube 30 of the deflection section 14( Figure 3 ), in which case the flush fluid exits the distal end of the flush tube 27 at the distal end of shaft 42 of the integral support member 40, as Figure 15A and Figure 25 shown. A suitable adhesive 90 (such as polyurethane) plugs and seals the lumen 43 around the distal end of the flush tube 27. In some embodiments, the catheter has no flush, and the distal end of shaft 42 of the integral support member 40 is integrally sealed with an adhesive or sealant 90 (such as polyurethane), as Figure 14A shown.

[0153] Figure 16 An embodiment is shown in which the non-conductive ridge tube 28 includes a reinforcing tensile member 53. As will be understood by those of ordinary skill in the art, the microelectrodes 18 are mounted on the ridge cover or tube 28, in which an elongate tubular mandrel (not shown) is positioned within the lumen of the ridge cover 28 to support the microelectrodes 18 when the microelectrodes are rotary swaged onto the ridge cover 28. The microelectrodes 18 may have a circular cross-section, including a circular or oval configuration. To prevent or at least minimize undesired deformation of the microelectrodes 18 and the ridge cover 28 during swaging, including elongation in the longitudinal direction, the ridge cover 28 on which the microelectrodes are carried and swaged includes a reinforcing tensile member 53, as Figure 16 shown. The tensile member 53 (such as wire or fiber (used interchangeably herein)) is embedded in the sidewall 54 of the tube (such as during extrusion of the tensile member). The tensile member 53 may be embedded in the non-conductive cover extrusion in a uniaxial or braided pattern, extending in the longitudinal direction or at least having a portion extending in the longitudinal direction. Thus, the tensile member serves to resist undesired elongation of the particularly soft and flexible ridge cover 28 and microelectrodes 18 in the longitudinal direction. Examples of suitable tensile members include VECTRAN, DACRON, KEVLAR, or other materials having low elongation characteristics. A plurality of reinforcing tensile members is not critical. In some embodiments, "a plurality" may range between two and six arranged in a radially equidistant configuration. In the illustrated embodiment, the ridge cover 28 includes four tensile members around the sidewall 54 at 0 degrees, 90 degrees, 180 degrees, and 270 degrees.

[0154] In some embodiments, the distal end of the tension member 53 is anchored in the bulbous covering 45 of the enlarged distal portion of the encapsulation ridge 17, and / or the loop 99D (as Figure 16 shown) can be compressed or clamped onto the ridge covering 28 and the ridge 17. In some embodiments, the proximal end of the tension member 53 coextends with the proximal end of the ridge covering 28 and can also be anchored by the loop 99P (see Figure 14A and Figure 15A ).

[0155] In some embodiments, the tension member 53 has a much greater length. Referring to Figure 17 , Figure 18 , Figure 19 and Figure 20 , the tension member 53 extends through an opening 44 formed in the rod 42 of the one-piece support member 40 and into the lumen 43 of the rod 42. The tension member 53 then extends through the lumen 71 of the housing insert 60, the lumen 31F of the lumen 30 of the deflection section 14, and the central lumen 19 of the catheter body 12, and into the control handle 16. The proximal end of the tension member 53 is configured to be manipulated by an operator to deflect the ridges 17 of the distal microelectrode assembly 15 such that they can be used individually as "fingers". In this regard, the tension member can be formed in the sidewall of the tube 28 in a manner that allows longitudinal movement relative to the tube 28 such that any one or more of the tension members can be pulled proximally to bend or deflect the corresponding ridge toward the side along which those tension members extend. Thus, the operator is able to manipulate one or more ridges for individual deflection as needed or desired, including when the distal microelectrode assembly is in contact with an uneven tissue surface, in which case one or more ridges need to be adjusted for better tissue contact.

[0156] Referring to Figure 21 , Figure 22 , Figure 23 and Figure 24 , the catheter 10 of the present invention is shown being used in all four chambers of the heart (i.e., the left atrium and right atrium, the left ventricle and right ventricle), where the ridges of the distal microelectrode assembly 15 readily adapt and conform to the various contours and surfaces of the heart tissue anatomy (including, for example, inside the pulmonary veins, and on the posterior wall of the right atrium, the anterior, inferior, and / or lateral walls of the left and right ventricles, and the apex). Regardless of the surface anatomy, the preformed configuration of the ridges advantageously facilitates contact between the microelectrodes carried on the ridges and the tissue.

[0157] In some embodiments, the catheter 10 has a plurality of annular microelectrodes proximal to the distal microelectrode assembly 15. In addition to the annular microelectrode 67, as Figure 1As shown, the catheter also carries another annular electrode 69 that is more proximal than the annular microelectrode 67, and another annular microelectrode 70 that is more proximal than the annular microelectrode 69. Leads 25 are provided for these annular microelectrodes. In some embodiments, the annular microelectrode 69 is located near the distal end 30D of the multi-lumen tube 30 of the deflection section 14, and the annular microelectrode 70 is separated from the annular microelectrode 69 by a distance S within a range between about 1 mm and 3 mm. The corresponding leads 25 are connected to the annular microelectrode 67 via openings 75 formed in the shaft 42 of the one-piece support member 40 and in the sleeve 68. The corresponding leads 25 for the annular microelectrodes 69 and 70 are connected to through-hole openings (not shown) formed in the side walls of the tube 30 of the deflection segment 14.

[0158] The extensions of the pull wires 23A and 23B through each part of the catheter body 12 are circumferentially surrounded by corresponding compression coils 101A and 101B, as is understood in the art. The extensions of the pull wires 23A and 23B through each part of the multi-lumen tube 30 of the deflection section are circumferentially surrounded by a sheath that protects the pull wires so that the pull wires do not cut into the tube during deflection. As is understood in the art, the distal ends of the pull wires can be anchored in the side walls of the tube 30 at or near the distal end of the tube 30. As is understood in the art, the proximal ends of the pull wires are anchored in the control handle 16 for actuation by the operator of the catheter.

[0159] The foregoing description has been presented with reference to the presently preferred embodiments of the invention. Those skilled in the art to which the invention pertains will know that changes and modifications can be made to the described structure without departing intentionally from the principles, essence, and scope of the invention. Any feature or structure disclosed in one embodiment can be incorporated, as needed or appropriate, in place of or in addition to other features of any other embodiment. As is understood by those of ordinary skill in the art, the drawings are not necessarily drawn to scale. Therefore, the above detailed description should not be construed as being limited only to the precise structures shown and described in the drawings, but rather should be construed as being in accordance with and supporting the following claims, which have the full and fair scope of the invention.

Claims

1. A medical probe, comprising: an elongate member extending along a longitudinal axis; a distal electrode assembly coupled to the elongate member, the electrode assembly comprising: a proximal rod extending along the longitudinal axis; a first ridge radiating away from the longitudinal axis, the first ridge having a plurality of first microelectrodes disposed thereon; a second ridge adjacent to and radiating away from the first ridge and away from the longitudinal axis, the second ridge having a plurality of second microelectrodes disposed thereon such that a first virtual circle intersecting one of the plurality of first microelectrodes does not intersect any of the second microelectrodes, wherein the first virtual circle is centered generally on the longitudinal axis and is generally orthogonal to the longitudinal axis.

2. The medical probe according to claim 1, further comprising a third ridge adjacent to and radiating away from the first ridge and away from the longitudinal axis, the third ridge having a plurality of third microelectrodes disposed thereon such that a first virtual circle intersecting one of the plurality of first microelectrodes does not intersect any of the second and third microelectrodes.

3. The medical probe according to claim 2, wherein the proximal rod is disposed generally orthogonal to a flat surface, wherein the first, second, and third ridges contact the flat surface to define a radiating configuration of the ridges.

4. The medical probe according to claim 1, wherein there are eight ridges arranged in an equiangular configuration about the longitudinal axis.

5. An electrophysiological medical probe, comprising: a distal electrode assembly, the distal electrode assembly comprising: a proximal rod defining a longitudinal axis; a plurality of ridges extending along the longitudinal axis; a plurality of first microelectrodes disposed on a first ridge; a plurality of second microelectrodes disposed on a second ridge adjacent to the first ridge; wherein the plurality of first microelectrodes are spaced along the first ridge such that the first microelectrodes are offset from the second microelectrodes by a staggered distance measured along the longitudinal axis.

6. An electrophysiological medical probe, comprising: a distal electrode assembly, the distal electrode assembly comprising: a plurality of ridges, each ridge defining a longitudinal axis; a plurality of first microelectrodes disposed on a first ridge, each of the first microelectrodes having a centerline disposed at an offset distance relative to the longitudinal axis of the first ridge in a first direction generally transverse to the longitudinal axis; and a plurality of second microelectrodes disposed on a second ridge adjacent to the first ridge, each of the second microelectrodes having a centerline disposed at an offset distance relative to the longitudinal axis in a second direction away from the first direction.

7. The probe according to claim 6, wherein the plurality of first microelectrodes are spaced along the first ridge such that the first microelectrodes are offset from the second microelectrodes by a staggered distance measured along the longitudinal axis.

8. The probe according to claim 5, wherein each of the first microelectrodes includes a centerline that is disposed at an eccentric distance relative to the longitudinal axis of the first ridge in a first direction that is substantially transverse to the longitudinal axis; and a plurality of second microelectrodes disposed on a second ridge adjacent to the first ridge, each of the second microelectrodes having a centerline that is disposed at an eccentric distance relative to the longitudinal axis in a second direction away from the first direction.

9. The probe according to claim 5, further comprising a plurality of third microelectrodes disposed on a third ridge adjacent to the first ridge, the plurality of first microelectrodes being spaced along the first ridge such that the first microelectrodes are offset from the second microelectrodes and the third microelectrodes by the staggered distance.

10. The medical probe according to claim 9, wherein the staggered distance includes any distance from 0.1 mm to 5 mm as measured between the leading edge of one electrode on one ridge and the leading edge of the nearest electrode on an adjacent ridge.

11. The medical probe according to claim 9, wherein the microelectrodes on each ridge are separated by a distance within the range of between 1 mm and 3 mm as measured between the leading edges of the microelectrodes.

12. The medical probe according to claim 9, wherein the staggered distance includes a distance of about 2 mm.

13. The medical probe according to claim 9, wherein the microelectrodes on each ridge are arranged in bipolar pairs, wherein the leading edges of the microelectrodes within a pair are separated by a first distance within the range of between 1 mm and 3 mm, and wherein the leading edges of the front microelectrodes between pairs are separated by a second distance within the range of between 1 mm and 6 mm.

14. The medical probe according to claim 13, wherein the first distance includes about 2 mm, and the second distance includes about 6 mm.

15. The medical probe according to claim 9, wherein the number of microelectrodes is equal to 64.

16. The medical probe according to claim 9, wherein the number of microelectrodes is equal to 72.

17. The medical probe according to claim 9, further comprising: a first annular microelectrode carried on the proximal rod of the distal electrode assembly; and a second annular microelectrode and a third annular microelectrode carried on the distal portion of the elongated body.

18. The medical probe according to claim 9, wherein each microelectrode has a length within any value range between 300 μm and 500 μm.

19. The medical probe according to claim 9, wherein the microelectrodes on each ridge are separated by a distance within the range of between 1 mm and 3 mm as measured between the leading edges of the microelectrodes.

20. The medical probe according to claim 19, wherein the staggered distance comprises about 2 mm.

21. The medical probe according to claim 9, wherein the microelectrodes on each ridge are arranged as bipolar pairs, wherein the leading edges of the microelectrodes within a pair are separated by a first distance within the range between 1 mm and 3 mm, and wherein the leading edges of the front microelectrodes between multiple pairs are separated by a second distance within the range between 1 mm and 6 mm.

22. The medical probe according to claim 21, wherein the first distance comprises about 2 mm, and the second distance comprises about 5 mm.

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