Distal assembly for a catheter with a lumen extending along the spine

Abstract

To provide a medical apparatus.SOLUTION: The medical apparatus includes an insertion tube configured for insertion into a body cavity of a patient, and a distal assembly including a plurality of spines having respective proximal ends that are connected distally to the insertion tube. Each spine includes a rib extending along a length of the spine, a flexible polymer sleeve disposed over the rib and defining a lumen running parallel to the rib along the spine, and one or more electrodes disposed on the sleeve and configured to contact tissue within the body cavity.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Broadly speaking, the present invention relates to invasive medical devices, and more specifically, to an apparatus for ablating tissue within the body and a method for producing such an apparatus.

Background Art

[0002] Cardiac arrhythmias are generally treated by ablation of myocardial tissue to interrupt arrhythmogenic electrical pathways. For this purpose, a catheter is inserted through the patient's vasculature into the heart chamber, and an electrode at the distal end of the catheter is contacted with the tissue to be ablated. In some cases, high-power radio-frequency (RF) electrical energy is applied to the electrode to thermally ablate the tissue. Alternatively, high-voltage pulses may be applied to the electrode to ablate the tissue by irreversible electroporation (IRE).

[0003] Electrical ablation, whether by RF thermal ablation or by IRE, generates excessive heat, which can cause collateral damage to the tissue inside and outside the ablation site. To reduce this type of damage by lowering the tissue temperature, the area of the electrode is generally perfused during the ablation procedure. In some catheters, perfusion is applied through small-diameter holes in the electrode itself, as described, for example, in U.S. Patent No. 8,475,450, owned by the applicant and incorporated herein by reference.

[0004] In some ablation procedures, a basket catheter is used, in which multiple electrodes are arranged along the spines of an expandable basket assembly at the distal end of the catheter. Various schemes for irrigating such a basket assembly during ablation have been described. For example, U.S. Patent No. 7,955,299 describes a basket catheter having an outer tube housing an inner fluid delivery tube having at least one fluid delivery port. Each of the multiple spines is connected to the outer tube at the proximal end of the spine and to the inner fluid delivery tube at the distal end of the spine. The inner fluid delivery tube is operable to move in a first direction to expand the spine and in a second direction to fold the spine. A porous membrane is provided on at least a portion of the inner fluid delivery tube. Seals are provided at the proximal end of the porous membrane, between the porous membrane and the outer tube, and between the porous membrane and the inner fluid delivery tube, but the seals are configured to irrigate between the multiple spines of the basket catheter while preventing fluid from entering the outer tube. [Overview of the Initiative] [Means for solving the problem]

[0005] Embodiments of the present invention described below provide an improved apparatus for ablating tissues within the body, as well as a method for producing such an apparatus.

[0006] Accordingly, embodiments of the present invention provide a medical device comprising an insertion tube configured to be inserted into a patient's body cavity, and a distal assembly comprising a plurality of spines, each having a proximal end connected to the distal side of the insertion tube. Each spine comprises a rib extending along the length of the spine, a flexible polymer sleeve disposed on the rib and defining a lumen extending parallel to the rib along the spine, and one or more electrodes disposed on the sleeve and configured to contact tissue in the body cavity.

[0007] In some embodiments, the spine has respective distal ends joined at the distal end of the distal assembly, and the rib is configured to curve radially outward when the distal assembly is deployed in a body cavity, thereby allowing the electrode to contact the tissue in the body cavity. In the disclosed embodiments, the rib is configured to fold radially inward so that the spine aligns along the axis of the insertion tube while the device is inserted in a body cavity. In addition to or instead thereof, the insertion tube includes a flexible catheter configured for insertion into the ventricles of the patient's heart, and the electrode is configured to contact the myocardial tissue in the ventricles and apply electrical energy to the myocardial tissue.

[0008] In the disclosed embodiments, the ribs include metal slats. In addition to or instead of thereto, the flexible polymer sleeve includes a thermoplastic elastomer.

[0009] In one embodiment, each lumen of a spine is in fluid communication with an irrigation manifold extending through an insertion tube, and the irrigation outlet is located near the electrodes and passes through a flexible polymer sleeve toward the lumen, thereby causing the irrigation fluid passing through the irrigation manifold to flow out of the lumen through the irrigation outlet. In addition to or instead of this, each spine includes a wire that extends through the lumen and is electrically connected to at least one of the electrodes.

[0010] According to embodiments of the present invention, a method for producing a medical device is also provided. This method includes forming a plurality of spines by arranging a mandrel along an elastic rib for each spine and molding a flexible polymer sleeve on the rib and mandrel. After molding the sleeve, the mandrel is removed so that the sleeve includes a lumen extending parallel to the rib along the spine. One or more electrodes are fixed to each sleeve of the spine. The proximal end of each spine is connected together to the distal end of an insertion tube configured to be inserted into the patient's body cavity.

[0011] In the disclosed embodiments, the flexible polymer sleeve comprises a thermoplastic elastomer tube, and forming the flexible polymer sleeve involves heating the thermoplastic elastomer tube to a temperature sufficient to shrink the thermoplastic elastomer tube into the shape of ribs and mandrels.

[0012] This invention will be more fully understood by considering the following "Modes for Carrying Out the Invention" in conjunction with the drawings. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram showing a system for cardiac ablation according to an embodiment of the present invention. [Figure 2A] This is a schematic side view of a catheter basket assembly in a folded configuration and an extended configuration according to an embodiment of the present invention. [Figure 2B] This is a schematic side view of a catheter basket assembly in a folded configuration and an extended configuration according to an embodiment of the present invention. [Figure 3] This is a schematic side view of the spine of a catheter basket assembly according to an embodiment of the present invention. [Figure 4] This is a schematic diagram showing details of the distal portion of the spine in Figure 3 according to an embodiment of the present invention. [Figure 5] This is a schematic cross-sectional view of a portion of the spine in Figure 4 along the longitudinal cutting line, according to an embodiment of the present invention. [Figure 6] This is a schematic cross-sectional view showing details of the proximal portion of the spine in Figure 3, according to an embodiment of the present invention. [Figure 7] This is a schematic cross-sectional view of the spine shown in Figure 4, according to an embodiment of the present invention. [Modes for carrying out the invention]

[0014] For efficient and reliable cooling of the ablation site, it is desirable that the irrigation fluid be specifically targeted to the location of the electrode. However, with basket catheters, mechanical constraints and strict size limitations make it difficult to deliver the irrigation fluid along the spine to the electrode. For example, it is possible to spray the irrigation fluid from the manifold within the basket assembly towards the electrode, but this approach requires a high irrigation flow rate and may not achieve sufficient tissue cooling.

[0015] Embodiments of the present invention described herein address this problem by providing a method for forming a lumen along the spine of a distal assembly of a catheter, and an assembly containing such a lumen. A spine having a lumen can be efficiently and reliably formed in the disclosed embodiment without substantially increasing the dimensions of the spine or altering its mechanical properties. Such a lumen can be used not only for transporting irrigation fluid to the location of an electrode along the spine, but also, additionally or alternatively, for other purposes such as routing wires along the spine. Although the embodiments described below relate specifically to basket catheters, the principles of the present invention can also be applied to other types of distal assemblies for medical probes, such as multi-arm catheters.

[0016] In the disclosed embodiments, the distal assembly of a medical probe, such as a cardiac catheter, comprises a plurality of spines, each having a proximal end that connects distally to an insertion tube configured to be inserted into a patient's body cavity. Each spine comprises ribs, such as metal slats, extending along the length of the spine. A flexible polymer sleeve is positioned above the ribs, defining a lumen that extends parallel to the ribs along the span. To create the lumen, in some embodiments, a mandrel is positioned alongside the ribs, the sleeve is positioned above the ribs and mandrel, the mandrel is then removed, and the lumen remains within the sleeve. One or more electrodes are fixed outward onto the sleeve to contact tissue in the body cavity.

[0017] Figure 1 is a schematic diagram of a system 20 used in an ablation procedure according to an embodiment of the present invention. The elements of system 20 may be based, for example, on components of the CARTO® system manufactured by Biosense Webster Inc. (Irvine, California).

[0018] Physician 30 navigates the catheter 22 through the patient 28's vascular system into the ventricle of the patient's heart 26, and then deploys the basket assembly 40 (shown in detail in Figure 2A / B) at the distal end of the catheter. The proximal end of the basket assembly 40 is connected to the distal end of the insertion tube 25, which Physician 30 manipulates using a manipulator 32 near the proximal end of the catheter 22. The basket assembly 40 is inserted through the sheath 23 in a folded configuration, and it passes through the patient 28's vascular system into the ventricle where the ablation procedure will be performed. Once inserted into the ventricle, the basket assembly 40 is deployed from the sheath and expanded within the ventricle. The catheter 22 is connected to the control console 24 at its proximal end. A display 27 on the console 24 may present a map 31 or other image of the ventricle, along with an icon indicating the location of the basket assembly, to assist Physician 30 in positioning the basket assembly 40 at the target location for the ablation procedure.

[0019] Once the basket assembly 40 is properly disposed and positioned within the heart 26, the physician 30 activates the electrical signal generator 38 within the console 24 to apply electrical energy (such as an IRE pulse or RF waveform) to the electrodes on the basket assembly under the control of the processor 36. The electrical energy can be applied between electrode pairs on the basket assembly 40 in bipolar mode or between an electrode on the basket assembly 40 and a separate common electrode, such as a conductive back patch 41 applied to the patient's skin, in monopolar mode. During the ablation procedure, the perfusion pump 34 delivers a perfusion fluid, such as a saline solution, to the basket assembly 40 through the insertion tube 25.

[0020] Typically, the catheter 22 includes one or more position sensors (not shown) that output a position signal indicating the position (presence position and orientation) of the basket assembly 40. For example, the basket assembly 40 can incorporate one or more magnetic sensors that output an electrical signal in response to an applied magnetic field. The processor 36 is known in the art and receives and processes signals to find the coordinates of the presence position and orientation of the basket assembly 40, for example, using the techniques implemented in the above-described CARTO system. Alternatively, or in addition thereto, the system 20 may apply other position sensing techniques to find the coordinates of the basket assembly 40. For example, the processor 36 can sense the impedance between an electrode on the basket assembly 40 and a body surface electrode 39 applied to the chest of the patient 28 and can also convert the impedance to coordinates of the presence position using techniques similarly known in the art. In either case, the processor 36 uses the coordinates when displaying the presence position of the basket assembly 40 on the map 31.

[0021] Alternatively, the catheter 22 and ablation techniques described herein can be used without the benefit of position sensing. In such embodiments, for example, fluoroscopy and / or other imaging techniques can be used to confirm the presence position of the basket assembly 40 within the heart 26.

[0022] The system configuration shown in FIG. 1 is presented as an example for clarifying concepts when understanding the operation of embodiments of the present invention. For simplicity, FIG. 1 shows only those elements of system 20 that are specifically related to the basket assembly 40 and the ablation procedure using that basket assembly. It will be clear to those skilled in the art that the remaining elements of the system will be similarly understood to be such that the principles of the present invention can be implemented in other medical treatment systems using other components. All such alternative implementations are considered to be within the scope of the present invention.

[0023] FIGS. 2A and 2B are schematic side views of a basket assembly 40 in a folded configuration and an expanded configuration, respectively, according to an alternative embodiment of the present invention. The basket assembly 40 has a distal end 48 and a proximal end 50, and the proximal end 50 is connected to the distal end 52 of an insertion tube 25. The basket assembly includes a plurality of spines 44, the proximal ends of which are joined at the proximal end 50 and the distal ends of which are joined at the distal end 48. One or more electrodes 54 are disposed outwardly on each of the spines 44. The irrigation outlet 56 within the spine 44 allows the irrigation fluid flowing within the spine to flow out in the vicinity of the electrode 54 and irrigate the tissue.

[0024] In the folded state shown in Figure 2A, the spine 44 is straight and aligned parallel to the longitudinal axis 42 of the insertion tube 25 to facilitate insertion of the basket assembly 40 into the heart 26. In the expanded state shown in Figure 2B, the spine 44 is curved radially outward, bringing the electrodes 54 on the spine 44 into contact with the tissue within the heart. In one embodiment, the spine 44 is manufactured such that the stable state of the basket assembly 40 is the folded state shown in Figure 2A. In this case, the basket assembly 40 is expanded by pulling a puller 46, such as a suitable wire, proximal through the insertion tube 25 once it is pushed out of the sheath. Releasing the puller 46 allows the basket assembly 40 to be folded back to its folded state. In another embodiment, the spine 44 is manufactured such that the stable state of the basket assembly 40 is the expanded state shown in Figure 2B. In this case, the basket assembly 40 is released into an expanded state when pushed out of the sheath, and the puller 46 may be replaced by a pusher rod to move distally before the sheath is pushed distally and surrounds the straight spine, thereby straightening the spine 44.

[0025] Figures 3 and 4 schematically show details of a representative spine 44 within a basket assembly 40 according to an embodiment of the present invention. Figure 3 is a side view of the spine 44, and Figure 4 is a diagram of the spine 44 (without electrodes 44) viewed from outside the basket assembly at a certain angle. The electrodes 54 are shown between the irrigation outlets 56 in Figure 3, but are omitted from Figure 4 for visual clarity.

[0026] As shown in Figure 3, the lumen 62 within the spine 44 is in fluid communication with an irrigation manifold 60, which includes a tube extending through the insertion tube 25. Thus, the irrigation fluid, pressurized through the irrigation manifold 60, flows out of the lumen 62 through the irrigation outlet 56. Alternatively, or in addition to the above, the lumen 62 may include a wire 70 (shown in Figure 7) electrically connected to the electrode 54.

[0027] Referring now to Figures 5 and 7, these figures schematically illustrate the details of a method for structurally producing a spine 44 according to embodiments of the present invention. Figure 5 is a cross-sectional view of a portion of the spine 44 along the longitudinal cutting line (without electrodes 54 for clarity), and Figure 7 is a cross-sectional view through the spine along the radial cutting line. Figure 6 is a cross-sectional view showing details of the proximal portion of the spine 44, including the connection of the lumen 62 to the irrigation manifold 60.

[0028] The spine 44 comprises ribs 64 extending along the length of the spine, the ribs having a shape corresponding to the equilibrium shape of the spine. In exemplary embodiments, the ribs 64 comprise relatively rigid slats, such as long, thin pieces of biocompatible material, such as nickel-titanium, having a desired curved or straight equilibrium shape. The ribs 64 have a first surface 64a and an opposite surface 64b, which are aligned with each other (e.g., parallel or non-parallel). The embodiment in Figure 7 shows a rectangular cross-section with main surfaces 64a and 64b, but the present invention is not limited to such a configuration, as long as two main surfaces can be formed that extend together (e.g., parallel or non-parallel) to define a slat or rib. The lumen 62 in this embodiment extends, for example, along surface 64a and along only one of the sides of the rib 64, as shown in Figure 7.

[0029] To form the lumen 62, a mandrel shaped like the lumen 62 is positioned along the ribs 64, and a thermoplastic elastomer tube or sleeve 66 is mounted on top of the ribs 64 and mandrel. In one embodiment, the mandrel is made from a flexible, self-lubricating polymer with a high melting temperature, such as polytetrafluoroethylene (PTFE). The elastomer tube or sleeve 66 includes a biocompatible material with suitable heat shrinkage properties, such as Pebax® polyether block amide shrink tubing. The elastomer sleeve 66 is mounted on the ribs 64, and the entire assembly is heated to a temperature sufficient to shrink the elastomer tube or sleeve 66 to the shape of the underlying ribs 64 and mandrel, thereby forming a sleeve 66 having the type of profile shown in Figure 7. Alternatively, the ribs 64 may be placed in a mold, and a thermoplastic material may be used in conjunction with a mold to form the sleeve 66 as a molded spine member. The mandrel inside the elastomer sleeve (or molded member) 66 is removed, leaving the lumen 62 open within the sleeve 66 along with the ribs 64. The distal end of Lumen 62 is sealed and closed.

[0030] When lumen 62 is used for irrigation, manifold 60 is mounted on the proximal end of lumen 62 during the manufacturing process. Manifold 60 includes, for example, a polyimide tube attached to the proximal end of rib 64, and an elastomer tube mounted on top of the distal end of the manifold. When the elastomer tube is heated, it contracts around manifold 60 so that lumen 62 is in fluid communication with manifold 60, as shown in Figure 6. A hole is formed in lumen 62 by puncturing, drilling, or laser drilling through sleeve 66 so that an irrigation outlet 56 is created. One or more electrodes 54 are mounted and fastened on the outer surface of sleeve 66, for example, using suitable epoxy and / or mechanical fasteners, and a wire (not shown) extends between the electrode and insertion tube 25 along spine 44 or through lumen 62. The irrigation holes 56 may also be provided in the electrode 55 itself by forming holes that extend through the electrode 54 and through the flexible sleeve 66, so that the irrigation fluid flows through the manifold 60 through the lumen 62 (of the sleeve 66) and out through the irrigation holes 56 of the electrode 54.

[0031] It should be noted that the irrigation holes 56 do not need to be perpendicular to the ribs 64, and can be angled at approximately 45 degrees to 135 degrees relative to the ribs 64 (longitudinal axis 42). Figure 5 shows that one outlet hole 56' (on the electrode 54) is angled to obtain a desired irrigation flow pattern around the electrode contact surface with body tissue. Other arrangements of this feature are also within the scope of the present invention. For example, all irrigation holes 56 on the sleeve 66 (not on the electrode 54) may be angled to spray toward the electrode 54, but the irrigation holes 66 on the electrode 54 may be perpendicular to the ribs 64. Alternatively, some of the irrigation holes 56 on the sleeve 66 may be angled away from the electrode 54, while other irrigation holes 56' are angled toward the electrode 54. The electrode 54 may be configured to have several holes 56' on the electrode 54 for flow perpendicular to the rib 64 (or axis 42), and several holes 56' (referred to as 56' and axis 42 in Figure 5) that make an angle β with respect to the longitudinal axis 42.

[0032] It should be noted that the hole 56' may be formed through the sleeve 66 (without passing through the electrode 54) for the purpose of electrically connecting the electrode 54 to a wire or conductor disposed within the lumen 62. The wire disposed within the lumen 62 may extend to the proximal handle of the device in order to allow signals to flow to and from the electrode 54.

[0033] After multiple spines 44 are fabricated in this manner, they are grouped and joined together to form a basket assembly 40 which is fixed to the distal end of the insertion tube 25 as shown in Figure 2A / B.

[0034] The embodiments described above are illustrative examples, and it will be understood that the present invention is not limited to those specifically illustrated and described above. Rather, the scope of the present invention includes both combinations and partial combinations of the various features described herein, as well as variations and modifications thereof not disclosed in the prior art, which would be conceived by those skilled in the art upon reading the foregoing description.

[0035] [Implementation Method] (1) A medical device, An insertion tube configured for insertion into a patient's body cavity, A distal assembly extending along a longitudinal axis, comprising a plurality of spines, each having a proximal end connected to the distal side of the insertion tube, each spine is Ribs extending along the length of the longitudinal axis, A medical device comprising a distal assembly, which includes a flexible polymer sleeve disposed on the rib and defining a lumen extending parallel to the rib only on one side of the rib. (2) The apparatus according to Embodiment 1, further comprising one or more electrodes disposed on the flexible polymer sleeve. (3) The apparatus according to Embodiment 2, wherein the spine includes each distal end joined at the distal end of the distal assembly, and the rib is configured to curve radially outward when the distal assembly is deployed in the body cavity, thereby the electrode contacts the tissue in the body cavity. (4) The apparatus according to Embodiment 3, wherein the rib is configured to fold radially inward so that the spine is aligned along the axis of the insertion tube while the apparatus is inserted into the body cavity. (5) The apparatus according to Embodiment 2, wherein the insertion tube includes a flexible catheter configured for insertion into the ventricle of the patient's heart, and the electrodes are configured to contact the myocardial tissue in the ventricle and apply electrical energy to the myocardial tissue.

[0036] (6) The apparatus according to Embodiment 1, wherein the ribs include metal slats. (7) The apparatus according to Embodiment 1, wherein the flexible polymer sleeve comprises a thermoplastic elastomer. (8) The apparatus according to Embodiment 2, wherein each lumen of the spine is in fluid communication with an irrigation manifold extending through the insertion tube, and the irrigation outlet is toward the lumen, passing through the flexible polymer sleeve near the electrode, thereby causing the irrigation fluid passing through the irrigation manifold to flow out of the lumen through the irrigation outlet. (9) The apparatus according to Embodiment 2, wherein each spine comprises a wire extending through the lumen and electrically connected to at least one of the electrodes. (10) The apparatus according to Embodiment 8, wherein the irrigation outlet includes at least two irrigation outlets arranged around each electrode.

[0037] (11) The apparatus according to Embodiment 8, wherein at least one of the irrigation outlets passes through the polymer sleeve and also passes through the electrode. (12) The apparatus according to embodiment 10, wherein each of the irrigation outlets is angled to approximately 45 degrees to approximately 135 degrees with respect to the longitudinal axis. (13) A method for producing a medical device, Multiple spines, For each spine, position the mandrel along the elastic rib. Forming a flexible polymer sleeve on the ribs and the mandrel, and Forming the sleeve by removing the mandrel after forming the sleeve, such that the sleeve includes a lumen extending parallel to the rib along one side of the spine, One or more electrodes are fixed to each of the sleeves of the spine, A method comprising connecting the proximal ends of each of the spines together to the distal end of an insertion tube configured to be inserted into a patient's body cavity. (14) The method according to Embodiment 13, further comprising joining the distal ends of the spines to form a basket assembly, wherein the ribs curve radially outward when the device is deployed in the body cavity, so that the electrodes contact the tissue in the body cavity. (15) The method according to embodiment 13, wherein the rib is configured to fold radially inward so that the spine is aligned along the axis of the insertion tube while the device is inserted into the body cavity.

[0038] (16) The method according to Embodiment 13, wherein the insertion tube includes a flexible catheter configured for insertion into the ventricle of the patient's heart, and the electrodes are configured to contact the myocardial tissue in the ventricle and to apply electrical energy to the myocardial tissue. (17) The method according to embodiment 13, wherein the elastic rib includes a metal slat. (18) The method according to embodiment 13, wherein the flexible polymer sleeve includes a thermoplastic elastomer tube. (19) The method according to Embodiment 18, wherein forming the flexible polymer sleeve involves heating the thermoplastic elastomer tube to a temperature sufficient to shrink the thermoplastic elastomer tube into the shape of the ribs and the mandrel. (20) The method of Embodiment 13, further comprising connecting the lumens of each of the spines to an irrigation manifold extending through the insertion tube, and forming an irrigation outlet near the electrode that leads to the lumen through the flexible polymer sleeve, thereby allowing the irrigation fluid passing through the irrigation manifold to flow out of the lumen through the irrigation outlet.

[0039] (21) The method according to Embodiment 13, further comprising passing a wire through the lumen and electrically connecting the wire to at least one of the electrodes.

Claims

1. It is a medical device, An insertion tube configured for insertion into a patient's body cavity, A distal assembly extending along a longitudinal axis, comprising a plurality of spines, each having a proximal end connected to the distal side of the insertion tube, each spine is A rib extending along the length of the longitudinal axis, A flexible polymer sleeve disposed on the rib and defining a lumen that extends parallel to the rib only on one side surface of the rib, A distal assembly comprising one or more electrodes disposed on the flexible polymer sleeve, A medical device in which each of the lumens of the spines is in fluid communication with an irrigation manifold extending through the insertion tube, and the irrigation outlet is located near the electrode, passing through the flexible polymer sleeve and toward the lumen, thereby causing the irrigation fluid passing through the irrigation manifold to flow out of the lumen through the irrigation outlet.

2. The medical device according to claim 1, wherein the spine includes each distal end joined at the distal end of the distal assembly, and the rib is configured to curve radially outward when the distal assembly is deployed in the body cavity, thereby the electrode contacts the tissue in the body cavity.

3. The medical device according to claim 2, wherein the rib is configured to fold radially inward so that the spine is aligned along the axis of the insertion tube while the medical device is inserted into the body cavity.

4. The medical device according to claim 1, wherein the insertion tube includes a flexible catheter configured for insertion into the ventricle of the patient's heart, and the electrode is configured to contact the myocardial tissue in the ventricle and apply electrical energy to the myocardial tissue.

5. The medical device according to claim 1, wherein the ribs include metal slats.

6. The medical device according to claim 1, wherein the flexible polymer sleeve comprises a thermoplastic elastomer.

7. The medical device according to claim 1, wherein each spine comprises a wire extending through the lumen and electrically connected to at least one of the electrodes.

8. The medical device according to claim 1, wherein the irrigation outlet includes at least two irrigation outlets arranged around each electrode.

9. The medical device according to claim 1, wherein at least one of the irrigation outlets passes through the flexible polymer sleeve and also passes through the electrode.

10. The medical device according to claim 8, wherein each of the irrigation outlets is angled at 45 to 135 degrees with respect to the longitudinal axis.

11. A method for producing medical devices, Multiple spines, For each spine, position the mandrel along the elastic rib. Forming a flexible polymer sleeve on the elastic rib and the mandrel, and After forming the flexible polymer sleeve, the mandrel is removed so that the flexible polymer sleeve includes a lumen extending parallel to the elastic rib along one side of the spine, One or more electrodes are fixed to each of the flexible polymer sleeves of the spine, A method comprising connecting the proximal ends of each of the spines together to the distal end of an insertion tube configured to be inserted into a patient's body cavity.

12. The method according to claim 11, further comprising joining the distal ends of the spines to form a basket assembly, wherein the elastic ribs curve radially outward when the medical device is deployed in the body cavity, thereby causing the electrodes to contact the tissue in the body cavity.

13. The method according to claim 11, wherein the elastic rib is configured to fold radially inward so that the spine is aligned along the axis of the insertion tube while the medical device is inserted into the body cavity.

14. The method according to claim 11, wherein the insertion tube includes a flexible catheter configured for insertion into a ventricle of the patient's heart, and the electrodes are configured to contact myocardial tissue within the ventricle and to apply electrical energy to the myocardial tissue.

15. The method according to claim 11, wherein the elastic ribs include metal slats.

16. The method according to claim 11, wherein the flexible polymer sleeve includes a thermoplastic elastomer tube.

17. The method according to claim 16, wherein forming the flexible polymer sleeve involves heating the thermoplastic elastomer tube to a temperature sufficient to shrink the thermoplastic elastomer tube into the shape of the elastic rib and the mandrel.

18. The method according to claim 11, further comprising connecting the lumens of each of the spines to an irrigation manifold extending through the insertion tube, and forming an irrigation outlet near the electrode that leads to the lumen through the flexible polymer sleeve, thereby allowing the irrigation fluid passing through the irrigation manifold to flow out of the lumen through the irrigation outlet.

19. The method according to claim 11, further comprising passing a wire through the lumen and electrically connecting the wire to at least one of the electrodes.

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