WO2017041890A1

WO2017041890A1 - Elongated medical device suitable for intravascular insertion and method of making an elongated medical device suitable for intravascular insertion

Info

Publication number: WO2017041890A1
Application number: PCT/EP2016/001513
Authority: WO
Inventors: Peter Ruppersberg
Original assignee: Ablacon Inc.
Priority date: 2015-09-07
Filing date: 2016-09-07
Publication date: 2017-03-16
Also published as: US20180279896A1; US10888236B2

Abstract

The present invention concerns an elongated medical device (1) suitable for intravascular insertion. Said device comprising a flexible elongated body (2) having a distal portion (3) with a distal end (4) and a proximal portion (5), and an electrode assembly (80) located at the distal portion (3) and including at least two support arms (81), each support arm (81) having a proximal part (81a), a distal part (81b) and a central part (81c) between the proximal part (81a) and the distal part (81b). Said device further comprising a plurality of electrodes (82) arranged on the at least two support arms (81), the at least two support arms (81) being configured to have an unexpanded condition (UC), where the at least two support arms (81) fit closely along a portion of the elongated body (2), and to have an expanded condition (EC), where at least a part of each of the at least two support arms (81) project away from the elongated body (2), wherein at least the central parts (81c) of the at least two support arms (81) are wound in a spiral in the expanded condition (EC) of the support arms (81), forming a spiral structure (83) with at least two spiral arms (84) and with the distal end (4) being located in a center of symmetry (C) of the spiral structure (83).

Description

ELONGATED MEDICAL DEVICE SUITABLE FOR INTRAVASCULAR

INSERTION AND METHOD OF MAKING AN ELONGATED MEDICAL DEVICE SUITABLE FOR INTRAVASCULAR INSERTION

The present invention relates generally to elongated medical devices suitable for intravascular insertion, comprising a flexible elongated body having a distal portion with a distal end and a proximal portion, an electrode assembly located at the distal portion and including at least two support arms, each support arm having a proximal part, a distal part and a central part between the proximal part and the distal part, a plurality of electrodes arranged on the at least two support arms, the at least two support arms being configured to have an unexpanded condition, where the at least two support arms fit closely along a portion of the elongated body, and to have an expanded condition, where at least a part of each of the at least two support arms project away from the elongated body. Such elongated medical devices suitable for intravascular insertion may be manually or robotically steerable catheters for the exploration or treatment of vessels or organs or other body cavities or guide wires for guiding catheters or the like medical apparatuses.

Further, the present invention relates to a method of making an elongated medical devices suitable for intravascular insertion, especially a mapping catheter. The present invention especially relates to an elongated medical device suitable for intravascular insertion with individual features of claim 1 , and to a method of making an elongated medical devices suitable for intravascular insertion, with individual features of the respective independent method claim.

Elongated medical devices suitable for intravascular insertion, such as catheters, especially ablation catheters, and guide wires for guiding catheters through vessels, organs or other body cavities are e.g. used in the treatment of atrial fibrillation (Afib). Atrial fibrillation is the most frequent arrhythmic disorder of the heart. Blood clotting occurring in the fibrillating atria is one main cause of stroke. In so far, Afib is one of the most important disorders associated with a high fatal risk. The cause for Afib has been subject to intensive scientific investigations and is meanwhile largely understood. In most patients, the pulmonary veins draining into the left atrium are the sources of rapid arrhythmic action potentials which trigger circular excitation patterns (rotors), i n the left atrium that induce a high frequency fibri llation through their re-entry mechanism. Those rotors have the character of smal l action potential cyclones of 2 to 3 cm² in size. The li kelihood of occurrence of those rotors and the frequency of pathological action potential generation in the pulmonary veins increases with fibrotic structural changes and certai n modifications of ion channel expression patterns in atrial cells with age.

The only potential ly curative treatments for Afib are open heart surgery or catheter ablation of those parts of the atrial wall tissue which originate, transmit or maintain the pathologic excitation ci rcles.

Today the use of catheter ablation like open heart surgery is sti ll limited by the potential ly fatal risk of some severe side effects associated with the procedure: When the integrity of the atrial wal l is destroyed by too i ntense ablation, perforations of the atrial wall into the pericar- dium or fistulas into the esophagus can have severe to deadly outcomes. The alteration of the endocardial cel ls on a larger surface can initiate clotting in the treated atrium which may lead to deadly strokes. That is why the procedure requires fu ll anticoagulation. Last but not least, if the i ntensity of the ablation is kept too low to avoid those side effects i n many cases the therapeutic effect is insufficient and patients face a success rate of the treatment of only 50- 70% on average.

To improve the situation, mapping catheters are used to first identify circular excitation patterns (rotors) in the left atrium. After identification of rotors, force sensing catheters are used that al low to better control the catheter positioni ng pressure which has an influence on the i ntensity of ablation. Further, water irrigation tries to keep the endothelial tissue free of lesions and micro-calorimetric sensors try to measure and control the heat in the tissue.

US 8,364,234 discloses a system for sensing multiple local electric voltages from endocardial surface of a heart. The system includes a first elongate tubular member; a basket assembly having a plurality of flexible spli nes for guiding a plural ity of exposed electrodes, the splines having proximal portions, distal portions and medial portions therei n between; a proximal anchor for securely affixing the proximal portions of the spl i nes; the proximal anchor being secured at the distal end of the first elongate tubular member; a distal tip consisti ng essential ly of means for only securely affixing the distal portions of the splines wherein at least some of the splines in the radially expanded non-spherical shape contain a distal excurvate outward bend disposed at the distal portion of the spline at a location near to the distal tip of the basket assembly to bend the splines back towards the proximal anchor. A disadvantage of this type of mapping system is the low resolution provided by the mapping electrode array, especially in the area of the equator of the system in its radially expanded shape.

US 7,081 ,1 14 B2 discloses a remotely deflectable electrophysiology/ablation catheter of the type intended for placing into an interior passage of the heart is disclosed. The distal end of this elongated tubular catheter has a pair of tension/compression members each with a flat- tened end portion connected to the distal electrode and extending through the catheter casing and attached to a user moveable actuator for effecting the tension/compression thereon for remotely curling the distal end of the catheter. Spaced ring electrodes are provided adjacent the distal electrode. A permanent bend is pre-formed in the casing and tension/compression members adjacent the ring electrodes about an axis perpendicular to the elongated ten- sion/compression members. Movement of the remote actuator causes the distal portion of the catheter to curl into a lariat in a plane perpendicular to the axis along the elongated catheter casing, thus permitting electrical mapping or ablation with the distal and/or ring electrodes about the inner surface of the heart passage into which the lariat is formed and situated. The lariat can achieve a curvature greater than 360 degrees and at a significantly reduced radius to allow insertion of the catheter distal end into passages of reduced dimension. A disadvantage of this catheter is the low resolution of the electrode array when used for mapping due to the limited number of electrodes and due to the relative large distances from electrode to electrode in the radial direction. WO 2012/09201 6 discloses a medical device having a distal end that is arranged in a spiral configuration having a single spiral arm extending between an elongated part of the device and its distal end, which is formed on the end of the spiral arm. The spiral configuration is generally planar and contains a number of electrodes for taking unipolar or bipolar measurements from a tissue. In one exemplary embodiment, the diameter of the outermost loop of the spiral configuration is twenty mi llimeters. The spiral configuration may contain multiple spiral loops. Anyhow, a first disadvantage of this device is that the maximum diameter of the spiral configuration loops is restricted by the diameter of the vessel, organ or other body cavity the device is to be introduced in. Further, the number of electrodes of this spiral configuration, even with more than one loop, is restricted due to the size limitations and hence maximum resolution is restricted too and there is a relative large "blind" area in the center of the spiral configuration.

US 2010/0094274 A1 discloses a sensor catheter in the form of an adjustable corkscrew de- sign, with a small number of spiral meridians ending on a blunt non-traumatic end. The meridians may include multiple elements, electrodes or probes. The corkscrew can be advanced or retracted into the sheath by manipulating the shaft, to increase or decrease the corkscrew size and/or probe spacing. A disadvantage of this geometry is that it will be difficult to control because it has a very long free ending. Further, it is almost impossible to judge if it really touches the surface.

US 2008/0275367 A1 discloses robotic instrument systems and methods for generating a geometric map of an area of body tissue which is correlated with a tissue characteristic such as tissue compliance or related property. The system comprises a robotically controlled catheter which is controlled by a robotic instrument driver. A force sensor system is provided that generates force signals responsive to a force applied to the distal end of the catheter. A position determination system is also provided which generates position signals responsive to the location of the distal end of the catheter. A computer is configured to receive and process the force signals and position signals to generate a geometric map of an area of body tissue cor- related to the tissue compliance of different regions of the body tissue or a tissue characteristic determinable from the tissue compliance.

It is hence an object of the present invention to provide an elongated medical device suitable for intravascular insertion that avoids the disadvantages of the prior art and which is fail-safe. It is a further/alternate object of the present invention to provide an elongated medical device suitable for intravascular insertion that allows for an enhanced electrode density and for electrode mapping of larger tissue areas.

It is a further object of the present invention to provide a method of making an elongated medical devices suitable for intravascular insertion that allows for an enhanced electrode density.

These and other objects of the present invention are accomplished by providing an elongated medical device suitable for intravascular insertion wherein at least the central parts of the at least two support arms are wound in a spiral in the expanded condition of the support arms, forming a spiral structure with at least two spiral arms and with the distal end being located in a center of symmetry of the spiral structure. The spirally structured electrode assembly according to the invention with at least two spiral arms allows for a relative even distribution of electrodes in a defined area and is fail-safe and inexpensive to produce. Further, the inventive spirally structured electrode assembly allows for an enhanced electrode density, allowing an electrode mapping of larger tissue areas as in the state of the art.

In an advantageous embodiment of the present invention, the electrode assembly includes a number of 2 plus n support arms, whereby n equals 2 to 30, preferentially 2 to 22, more preferentially 2 to 14. The advantage of this arrangement is that the density of electrodes can easily be increased without the need to provide a longer storage area at the elongated medical device for storing the electrode assembly in the unexpanded condition of the support arms when arranged closely along a portion of the elongated body.

In a further favorable embodiment of the invention, the distal portion of the elongated medical device defines a longitudinal axis, the center of symmetry of the spiral structure is located in the longitudinal axis and the spirally wound parts of the support arms lie in a plane that intersects the longitudinal axis perpendicularly. The advantage of this arrangement is a 2 to 2 plus n-fold rotation symmetry of the spiral structure with the longitudinal axis as a center of rotation with all electrodes arranged in a plane that is perpendicular to the longitudinal axis. The spiral structure of electrodes is but also flexible, so that when the spiral structure of elec- trades is pushed against a body surface, it will follow the topography of the body surface it is in contact with to obtain optimal electrode measurements. The spiral structure of electrodes thus forms a flexible planar screen. The advantage of which is a relatively uniform density of electrodes that may flexibly follow the topography of a body surface and provide high resolution electrophysiological data.

In an advantageous geometry according to the invention, the electrodes are located on the central parts of each of the support arms and the electrodes are lying in or are arranged in parallel to the plane, defined by the spiral structure, in the expanded condition of the support arms. In a further preferred embodiment of the invention, the distal parts of the support arms being attached to the distal portion adjacent the distal end and the proximal parts of the support arms being coupled to an axially movable member located on an end of the proximal portion facing the distal portion. The axially movable member may be coupled to an actuating member which could be part of a handle of the elongated medical device. By this means, the spirally structured electrode assembly may be easily transferred from its unexpanded condition to its expanded condition and vice versa from its expanded condition to its unexpanded condition. Axially movable thereby means that this member is movable relative to another part of the elongated medical device. So, actually, the other part (distal portion of the elongated body) may be moved and the axially movable member may be static.

In another preferred embodiment of the invention, the axially movable member is adapted to be moved back and forth between a first position and a second position, wherein a movement from the first position to the second position is in direction of the distal portion in order to dislocate the support arms from their unexpanded condition, where the at least two support arms fit closely along a portion of the elongated body, to their expanded condition, where at least the central parts of the at least two support arms are spirally wound and wherein a movement from the second position to the first position is in a direction away from the distal portion in order to dislocate the support arms from their expanded condition back into their unexpanded condition. This configuration contributes to an easy transfer of the spirally structured electrode assembly from its unexpanded condition to its expanded condition and vice versa from its expanded condition to its unexpanded condition. As mentioned above, the axially movable member may be static and the other part (distal portion) of the elongated body to which the distal parts of the support arms are being attached to may be moved.

In a further advantageous embodiment of the invention, each support arm comprises a strand formed of a shape memory metal and a PCB (Printed Circuit Board) layer, whereby the PCB layer carries the electrodes and the electric lines for contacting the electrodes electrically. Preferably, the strands are formed out of a shape memory metal, such as e.g. Nitinol, and memorize the spiral arm shape. The PCB^'s on the other hand, passively follow any shape the strands may possess. The PCB^'s at least partially surround or encapsulate the strands, thus protecting the strands. PCB ^'s and strands may be connected to each other by material bonding, e.g. by gluing or curing. In a further preferred embodiment of the present invention, on each of the support arms (a number of 8 to 30 electrodes is disposed. So, advantageously an electrode array of 1 6 electrodes (on a total of two spiral arms) to about 480 electrodes (on a total of sixteen spiral arms) may be achieved. Preferably a number of 8 to 18 electrodes is disposed on each of the support arms allowing for an electrode array of Ί 6 electrodes (on a total of two spiral arms) to about 288 electrodes (on a total of sixteen spiral arms). While low resolution electrode arrays of only 1 6 electrodes are sti ll possible, the invention allows for high resolution electrode arrays of 256 electrodes and even more up to about 480 electrodes.

In a further favorable embodiment of the present invention, the electrodes are gold plated, thus allowing for a high electrode sensitivity coupled with a very good bio-compatibility, avoiding defensive reactions of the immune system of the human or animal body.

In a further preferred embodiment of the present invention, the surface size of an electrode is between 0,01 mm² and 0,25 mm², which allows for an utilization of PCB^'s having a width of less than 1 mm while the electrodes sti ll have a satisfactory impedance of 10 kilo ohm to 1 mega ohm. Advantageously, two adjacent electrodes on an individual support arm are arranged in a distance to each other, wherein this distance is between 2 mm and 9 mm, preferably between 2.5 mm and 4.5 mm.

Further advantageously, two adjacent electrodes on two adjacent support arms are arranged in a distance to each other, wherein the distance is between 2 mm and 9 mm, preferentially between 2.5 mm and 4.5 mm.

In a further advantageous embodiment of the invention, the distance between two adjacent electrodes on an individual support arm and the distance between two adjacent electrodes on two adjacent support arms are equal within a maximum tolerance in a range of up to +/- 1 .5 mm. With these distances a resolution of about 1 to 36 electrodes per cm² are achieved. In a further preferred embodiment of the invention, the electrodes on the support arms are electrically connected to at least one electronic element of an electronics unit disposed at the distal portion adjacent the distal end. The electronic element of the electronic unit disposed at the distal portion adjacent the distal end of the elongated body has the advantage, that some processing of the electrode measurement data can already be performed in the elongated medical device. This will reduce noise and the sensitivity to electrical interference.

Advantageously, the at least on electronic element is configured to process and digitize analog signals received from the electrodes. Due to this advantageous data processing and digi- talization already in the distal end area of the device, the communication cables or wires needed for communication with the external data processing unit can be reduced in number, hence reducing the necessary construction volume and thus reducing the diameter of the elongated device even for a higher number of electrodes in the spiral ly structured electrode array.

Preferably, the at least one electronic element is an ASIC which comprises one or more operational amplifiers, at least one multiplexer and at least one analog-digital converter. Hence, signal transmission through the catheter can be done via a robust serial transmission and not via sensitive analog wires. In a further advantageous embodiment of the invention, the electronics unit with the at least one electronic element is adapted to be connected to a data processing and control unit that is configured to process digitized electrode measurement data and to output data for visualizing and displaying atrial rotors of a patient on a data output unit. Thus a better visibility and interpretability of muscular rotors is achieved, allowing the operator to exactly localize the rotor in terms of position and size.

Advantageously, the medical device is formed as a catheter for the exploration or treatment of a vessel, organ or other body cavity. This catheter contains one or more of the inventive features described before.

Alternatively, the medical device may be formed as a guide wire for guiding a catheter or the like medical apparatus through a vessel, organ or other body cavity, whereby the guide wire includes one or more of the inventive features described before. An advantageous method of making an elongated medical device, especially an electrophysiological mapping system assembly according to the invention especially an advantageous method of making an electrophysiological mapping catheter, comprises:

- Providing a set of at least 2 strands consisting of shape memory metal and memorizing a spiral arm shape in each of the strands of shape memory metal,

stretching each of the strands and attaching an electrode carrying PCB layer to each of the strands to form support arms; mounting the ends of the proximal parts of the support arms to an axial ly movable member and locating the axially movable steering - member at an end of a proximal portion of a pre-assembled part of the elongated device,

mounting the ends of the distal parts of the support arms to a distal portion of a pre- assembled part of the elongated device adjacent to the distal end,

electrically connecting the PCB^'s to at least one electronic element arranged at the distal portion of the pre-assembled part of the elongated device adjacent to the distal end.

Further features of the invention, its nature and various advantages will become more ap- parent from the accompanying drawings and the following detailed description of the preferred embodiments, in which:

Fig. 1 a is a schematic view of an elongated medical device in a first embodiment which is a catheter for exploration or treatment of a vessel or organ or other body cavity which includes an electrode assembly for electro-anatomic mapping of cardiac or vessel areas in a first, un- expanded condition of the electrode assembly;

Fig. 1 b is an enlarged view of the distal portion of the elongated medical device of Fig. 1 a according to the area marked lb in Fig. 1 a;

Fig. 1 c is an enlarged view of an area of the proximal portion of the elongated medical device of Fig. 1 a according to the area marked lc in Fig. 1 a; Fig. 1 d is an enlarged view of a proximal end area of the proximal portion of the elongated medical device of Fig. 1 a connected to a data processing and control unit / data output unit;

Fig. 2 is a schematic view of the elongated medical device of Fig. 1 a in a second, expanded condition of the electrode assembly;

Fig. 3 is a cut view of the elongated medical device according to the line III - III of Fig. 1 a;

Fig. 4 is a cut view of the elongated medical device according to the line IV - IV of Fig. 2;

Fig. 5 is a cut view of the elongated medical device according to the line V - V of Fig. 8;

Fig. 6 is a top view of the elongated medical device according to Fig. 2 in the second, expanded condition of the electrode assembly;

Fig. 6a is an enlarged view of an area of the electrode assembly of the elongated medical device of Fig. 6 according to the marking Via in Fig. 6;

Fig. 7 is a perspective view on the distal portion of the elongated medical device according to Fig. 2;

Fig. 8 is an enlarged perspective view of the distal end area of the elongated medical device of Fig. 2 in the second, expanded condition of the electrode assembly; Fig. 9 is a detail of the electrode assembly of the elongated medical device;

Fig. 9 is an enlarged detail of the electrode assembly of Fig. 9;

Fig. 10 is a top view of a further embodiment of the elongated medical device in the second, expanded condition of the electrode assembly;

Fig. 1 0a is an enlarged view of an area of the electrode assembly of the elongated medical device of Fig. 10 according to the marking Xa in Fig. 10; Fig. 1 1 is a top view of a sti ll further embodiment of the elongated medical device i n the second, expanded condition of the electrode assembly;

Fig. 1 1 a is an enlarged view of an area of the electrode assembly of the elongated medical device of Fig. 1 1 according to the marking Xla in Fig. 1 1 ;

Fig. 1 2 is a top view of a sti ll further embodiment of the elongated medical device in the second, expanded condition of the electrode assembly; Fig. 1 2a is an enlarged view of an area of the electrode assembly of the elongated medical device of Fig. 12 according to the marking Xlla in Fig. 12;

Fig. 1 3 is a top view of a sti ll further embodiment of the elongated medical device in the second, expanded condition of the electrode assembly;

Fig. 1 3a is an enlarged view of an area of the electrode assembly of the elongated medical device of Fig. 1 3 according to the marking Xllla in Fig. 1 3;

Fig. 1 4a is a representation of an exemplary visual output on the screen of the data output unit;

Fig. 1 4b is a representation of a further exemplary visual output on the screen of the data output unit. The present invention is directed to an elongated medical device suitable for intravascu lar i nsertion, such as a catheter for exploration or treatment of a vessel, organ or other body cavity which i ncludes an electrode assembly for electro-anatomic mapping of cardiac or vessel areas or the like medical apparatus. The medical device has a force sensor with which contact forces between a distal portion of the medical device and a wall of the vessel, organ or other body cavity can be measured. The electrode assembly may be used to map circular excitation patterns (rotors), e.g. of the left atrium of the heart, as wi l l be described in more detai l in the fol lowi ng. Referring to Fig. 1 a-1 0a and 14a-14b, an elongated medical device 1 is formed as a combined ablation and mapping catheter, e.g. to be used in the curative treatment of Atrial Fibrillation and other hearth rhythm diseases like Atrial Flutter, Accessory Pathways or Ventricular Tachycardia. The elongated medical device Ί comprises an elongated body 2, which is only partly shown in Figures 1 a and 2. At a distal portion 3 of the elongated medical device 1 , there is a tip electrode 6 arranged at its distal end 4 as can especially be depicted from Figures 1 b and 8. Further, at least one further electrode which is an annular ground electrode 8 is arranged at the distal portion 3 of the elongated body 2. Tip electrode 6 and ground electrode 8 are electrically isolated from each other and are used for electro-ablation of body tissue, e.g. in the left atrium of the heart, where rotors have been detected and tissue has to be treated. Between the two electrodes (6, 8) a flexible tube (56) is disposed which is an isolator.

As is depicted in Figures 3 and 4 a proximal portion 5 of the elongated body 2 is formed as a flexible tube and comprises an outer tube 29 made e.g. of a combination of a woven grid metal-layer and plastic and/or silicone rubber and/or ChronePrene™ and an inner tube 28 e.g. of a combination of a woven grid metal-layer and plastic and/or silicone rubber and/or ChronePrene™ in a radial distance of about 0.2 mm - 0.4 mm . Inside of the inner tube 29 there is an inner shaft-member 24 arranged which fills the inner tube volume of inner tube 28 and which is in sliding relation to inner tube 28. Inner shaft-member 24 may be made e.g. of a woven grid metal-layer and plastic and/or silicone rubber and/or ChronePrene™. Inner tube 28 and inner shaft-member 24 continue up to the distal portion, while the outer tube 29 ends at an annular steering member 25 which is axially movable.

Inside the inner shaft-member 24 member there are arranged a number of channels which include a first channel 23, second channels 87, through which mapping electrode cables 88 and ablation electrode cables 88a are guided along the elongated body 2 up to distal portion 3 with the respective electric components to be contacted, and fluid supply line 1 9 which is formed as a channel as well. The number of channels disposed in the inner shaft-member may vary upon the technical needs and the number of cable to be accommodated.

The elongated medical device 1 further comprises a fluid supply line 1 3, which may be connected to a fluid supply 1 7 (see Fig. 1 d). This fluid supply line 1 3 is in fluid-guiding connection to at least one fluid opening 1 8 in the tip electrode 6, through which an irrigation fluid, l ike e.g. a saline fluid, may flow to the outside of the distal portion 3 of the elongated medical device 1 to irrigate a surrounding portion of the vessel, organ or other body cavity into which the elongated medical device 1 has been introduced. Fluid flow is guided from the fluid supply line 1 3 through the fluid channel 1 9 (see figures 3, 4 and 5) in the elongated body 2. Fluid flow 63 through the fluid supply line 1 3 and the fluid channel 1 9 in the elongated medical device 1 to the at least one fluid opening 1 8 to the outside of the elongated medical device 1 is indicated by arrows 63 in Fig. 8. Fluid flow may be controlled by the handle 7 or by a control at the fluid supply 1 7. Irrigation fluid will be distributed especially during or after an electro-ablation procedure has been performed.

At the proximate end of the elongated medical device 1 a handle 7 is disposed which comprises a first handle part 7a and a second handle part 7b. Via the handle 7 electro-ablation using the electrodes 6, 8 can be initiated and also the operation of an electrode assembly 80 / mapping electrode assembly may be control led.

The electrode assembly 80 / mapping electrode assembly is located at the distal portion 3 and comprises in the embodiment of Figures 1 a - 8 eight support arms 81 , whereby it has to be mentioned that the invention requires at least two such support arms 81 . Each support arm 81 has a proximal part 81 a, a distal part 81 b and a central part 81 c between the proximal part 81 a and the distal part 81 b.

The distal parts 81 b of each of the support arms 81 are attached to the distal portion 3 adjacent to its distal end 4 and the proximal parts 81 a of the support arms 81 are coupled to a steering member 25 located on an end of the proximal portion 5 that faces the distal portion 3.

The support arms 81 are configured to have a first, unexpanded condition UC, in which the support arms 81 are arranged in a close fit along a portion of the elongated body 2, as is best seen in Figures 1 a - 1 c and 3. In this unexpanded condition UC of the support arms 81 the steering member 25 located in its first position 60, remote, or in other words in a maximum distance to the distal end 4.

With reference to Figures 2 and 6 - 6a, the support arms 81 are further configured to have a second, expanded condition EC, in which the central parts 81 c of each of the support arms 81 project away from the elongated body 2 and are spirally wound, forming a spiral structure 83 with eight spiral arms 84 and the distal end 4 being located in a center of symmetry C of the spiral structure 83. Spiral arms 84 essentially correspond to the central parts 81 c of the support arms. The center of symmetry C of the spiral structure 83 lies in a longitudinal axis A which is defined by the distal portion 3 of the elongated medical device 1 . In this second, expanded condition EC of the support arms 81 the steering member 25 located in its second position 70, nearby, or in other words in a minimum distance to the distal end 4. The spiral structure 83 with the spiral arms on the other hand define a plane P which intersects the longitudinal axis A essentially perpendicularly. Further, in this expanded condition EC of the support arms 81 the electrode assembly forms an electrode array of a plurality of electrodes 81 arranged essentially in the plane P. The electrode array in the present embodiment comprises 8 support arms 81 with each support arm carrying 1 8 electrodes so that the electrode array counts 8 times 18 electrodes summing up to a total of 144 electrodes and has a size of about 4.4 cm in diameter which is about 1 5.2 cm². The corresponding spatial resolution is about 1 0 times higher than that of existing electro-mapping technologies.

According to Fig. 6a, two adjacent electrodes 82 on an individual support arm 81 are arranged in a distance x to each other. This distance x is between 2 mm to 9 mm, preferably between 2.5 mm to 4.5 mm. Further, two adjacent electrodes 82 on two adjacent support arms 81 are arranged in a distance y to each other. This distance y is between 2 mm to 9 mm, preferentially between 2.5 mm to 4.5 mm. Distances x and y are correlated with each other in that the distance x and the distance y are equal within a maximum tolerance in a range of +/- 0,5 mm.

As can be taken out of Fig. 4, between the inner tube 28 and the outer tube 29 there are two guide channels 26 arranged in each of which a steering wire 27 is guided. The steering wires 27 are fixedly connected at one end to the annular steering member 25 and at their respective other end at the first handle part 7a of handle 7. By means of the handle 7a, which may be moved away from the second handle part 7b (see movement of first handle part 7a indicated by arrow 9 in Fig. 2), and the steering wires 27 the annular steering member 25 can be moved from its first position 60 towards the distal end 4 of the elongated medical device 1 into its second position 70 (see movement of annular steering member 25 indicated by arrow 1 0 in Fig. 2), reducing the distance between the annular steering member 25 and the distal end 4. With such movement of the annular steering member 25 the electrode assembly 80 / mapping electrode assembly and their eight support arms 81 will be transferred from their unexpanded condition UC to their expanded condition EC, opening and expanding the spiral structure 83 of the electrode assembly 81 . In this expanded condition EC the electrode assembly is ready for use in mapping circular excitation patterns (rotors), e.g. of the left atrium of the heart. Of course, a movement of the first handle part 7a in the other direction back towards the second handle part 7b, will close and collapse the spiral structure 83 of the electrode assembly 81 , transferring it to the unexpanded condition EC of the electrode assembly 80 / mapping electrode assembly and their eight support arms 81 .

The central part 81 c of each support arm 81 carries a plurality of electrodes 82 (also referenced to as mapping electrodes) which are gold-plated for enhanced electro-conductability, as can especially be seen in Fig. 6. In the present embodiment there are eighteen electrodes 82 disposed on each support arm. The surface size of an electrode 82 is between 0.01 mm² and 0.25 mm².

Referring to Figures 3 and 9, each of the support arms 81 comprises a strand 86 formed of a shape memory metal and a PCB (printed circuit board) layer 85, whereby the PCB layers 85 carry the electrodes 82 and electric lines 89 for contacting the electrodes 82 electrically. The PCB layers 85 at least partially surround the strands 86, which may be formed as Nitinol wires of 0.1 - 0.3 mm diameter, preferentially 0.2 mm diameter. The PCB layers 85 of two support arms 81 merge at their distal part 81 b and both contact an electronic element 91 of an electronic unit 90 which is arranged at the distal portion 3 (see Fig. 8 in this respect). The electronic unit 90 comprises four electronic elements 91 (see Fig. 5.) which are arranged radially outwardly on the distal end of the inner shaft-member 24. The hull 30 of this part of the distal portion, where the electronic unit 90 is located is again made of a silicone rubber or a ChronePrene™. As can be seen in Fig. 9, the electronic elements 91 , which are adapted to process and digitize analog signals received from the electrodes 82, are formed as ASIC^'s (application-specific integrated circuits). The ASIC^'s have a size of between 1 x 0.6 to 3 x 1 .8 mm, preferentially 2 x 1 .2 mm, and are located on the PCB layer 85 at the area where two support arms 81 merge together. To fulfil its tasks, each electronic element 91 / ASIC comprises a plurality of operational amplifiers 92, preferentially seventy two operational amplifiers 92, at least one multiplexer 93 and at least one analog-digital converter 94. Each of the electrodes 88 is connected via an electric line 89 to a respective operational amplifier 92 of the electronic element 91 .

The operational amplifiers 92 acquire AC inputs from the electrodes 82 on four wires / electric lines 89 with 1 00 ki lo ohm input resistance each and 1 s of time constant. Signals are low pass filtered at 200 Hz and read by the analog multiplexer 93 and through the 1 4 bit analog-digital converter 94 and forwarded into a serial LVDS digital output signal via mapping electrode cables 88 and data line 12 passing to a three channel serial interface.

The electrode assembly 80 with its electronics unit 90 and with the electronic elements 91 as well as the electrodes 6, 8 are connected via a line 12 with a data processing and control unit 1 5 (see Fig. 1 d), which energizes and controls the electrodes 6, 8. Data processing and control unit 1 5 processes electrode mapping data from the electrode assembly and outputs mapping data via a data output unit 1 6. Line 12 may be a ribbon cable, flat conductor, flat flexible cable or the like and combines mapping electrode cables 88 and ablation electrode cables 88a.

The data processing and control unit 1 5 may be formed as a standard personal computer and the elongated medical device 1 respectively the catheter system has an interface to a standard computer which is connected to all the electronic components.

In respect to the mapping data, the data processing and control unit 1 5 is configured to process digitized electrode measurement data and to output data for visualizing circular excitation pattern (rotors) 45 e.g. in the left atrium of a patient^'s heart on a data output unit 1 6 which will be explained in detail with respect to figures 14a and 14b. Figures 14a and 14b represent exemplary visual outputs on the screen or a sub-zone 14 of the data output unit 1 6.

A pre-condition of a meaningful electro-anatomic mapping is that a force sensing assembly of the elongated medical device 1 or catheter detects a sufficient perpendicular force vector F (see e.g. Fig. 2), indicating that the tip electrode 6 is in sufficient contact with the tissue (not displayed in the Figures) e.g. of the left atrium of the heart.

In electro-anatomical mapping systems the excitation in response to a pacing stimulus is measured while travel ling along the walls of the atrium. The path from one side to the other is around 6 cm and the excitation needs 200 ms for this distance. In rotors 45 the "eye of the storm" has a diameter of around 1 cm (circumference of 3 cm). Thus rotor excitation cycles have a period of 200 ms or 300 beats per minute. Since action potentials are about 100 ms in duration excitation clusters have a size of about 1 .5 cm. The data output unit 1 6 or monitor display shows the tissue e.g. of the left atrium of the heart as a 3D object visualized from outside with the atrial septum on the backside. As mentioned above, the respective excitation pattern map is put on the surface of this object as texture of electro-anatomic data arrows 40 upon a sufficient perpendicular force vector F. With the present elongated medical device 1 or mapping catheter system the excitation pattern or cluster has a length of about four to five electrode distances x, y. The circular excitation pattern 45 is recorded every 10 ms and visualized on a screen or sub-zone 1 4 of a screen of the data output unit 1 6 or monitor display by means of electro-anatomic data arrows 40. The circular excitation pattern (rotor) 45 travels with a speed of about half an electrode per meas- urement cycle. The amplitude pattern of the AC signal undergoes a software cluster analysis. Each cluster^'s center of gravity position is determined in each time interval. Electro-anatomic data arrows 40 are displayed on the sub-zone 1 4 of the screen of the data output unit 1 6 indicating the direction of movement of a circular excitation pattern (rotor) 45. The Electro- anatomic data arrows 40 indicate rotors 45 by their circulating behavior which is indicated by circular arrows 41 a and 42 in Fig. 14a, where two active rotors 45 may be identified. The high resolution of the electro-anatomic data arrow map will allow to see the excitation path also if the voltage amplitude is changing in case of fibrosis.

Fig. 14b shows the situation after electro-ablation of the rotor 45 indicated by circular arrow 41 b has taken place by using the ablation faci lity (tip electrode 6 and ground electrode 8) of the elongated medical device 1 or catheter. As can be seen in Fig. 14b, rotor 45 of Fig. 14a has vanished completely as indicated by circular arrow 41 b.

As mentioned above, data analysis of electrophysiological data, such as action potential data, is performed on the data processing and control unit 1 5 respectively on a standard computer by a software that comprises an image generator. In Fig. l a the elongated medical device 1 /catheter is displayed in a condition when it may be introduced into a vessel, organ or other body cavity and when the electrode assembly 80 and the support arms 81 are in their unexpanded condition UC. In operation of the medical device 1 , the medical device 1 or catheter will be inserted in the vessel, organ or other body cavity until it reaches the target area, which may e.g. be the left atrium of the heart. Upon arrival in the target area the operator may expand the electrode assembly 80 by moving first handle part 7a in direction of arrow 9, as displayed in Fig. 2. In this expanded condition EC of the electrode assembly 80 and its support arms 81 the medical device 1 will be pushed with its distal end 4 and respectively with its tip electrode 6 against body tissue exerting a force F on the distal end 4. Force F will be measured by the force sensing assembly. Upon detecting a sufficient force F, electro-anatomic mapping will be started either automatically or initiated by the operator as has been explained in detail above. Upon detection of circular excitation patterns (rotors) 45 electro ablation using the tip elec- trode 6 and ground electrode 8 will be initiated by the operator as has been explained in detail above.

Essentially, the inventive elongated medical device 1 or catheter is a multipurpose device which combines force detection, electro-anatomic mapping and ablation in one device.

Figs. 1 0 and 1 0a display a further embodiment of the elongated medical device 1 1 . For reference numerals and functions not described in the following text, reference is made to the description of Figs. 1 a to 9 which is herewith incorporated by reference. The embodiment of Figs. 10 and 1 0a differs from the one described in Figs. 1 a to 9 in that the electrode assembly 80 comprises six support arms 81 forming a spiral structure 83 with six spiral arms 84 in the expanded condition EC of the electrode assembly 80 and the support arms 81 . Each of the six support arms 81 carries eighteen electrodes 82. In Figs. 1 1 and 1 1 a a further embodiment of the elongated medical device 1 1 0 is shown. For reference numerals and functions not described in the following text, reference is made to the description of Figs. 1 a to 9 which is herewith incorporated by reference. The embodiment of Figs. 1 1 and 1 1 a differs from the one described in Figs. 1 a to 1 0a in that the electrode assembly 80 comprises twelve support arms 81 forming a spiral structure 83 with twelve spiral arms 84 in the expended condition EC of the electrode assembly 80 and the support arms 81 . Each of the support arms 81 carries eighteen electrodes.

Figs. 12 and 12a display a further embodiment of the elongated medical device 21 0. For reference numerals and functions not described in the following text, reference is made to the description of Figs. 1 a to 9 which is herewith incorporated by reference. The embodiment of Figs. 12 and 12a differs from the ones described in Figs. 1 a to 1 1 a in that the electrode assembly 80 comprises sixteen support arms forming a spiral structure 83 in the expanded condition of the electrode assembly 80 and support arms 81 that has sixteen spiral arms 84, whereby each of the spiral arms 84 carries sixteen electrodes 82.

In Figs. 1 3 to 13a another embodiment of the elongated medical device 31 0 is shown. For reference numerals and functions not described in the following text, reference is made to the description of Figs. 1 a to 9 which is herewith incorporated by reference.

The embodiment of Figs. 1 3 and 1 3a differs from the ones described in Figs. 1 a to 12a in that the electrode assembly 80 forms a spiral structure 83 in the expanded condition EC of the electrode assembly 80 and the support arms 81 that has eight spiral arms 84 which occupy a square like area in the expanded condition EC. The spiral arms 84 are partly curved and partly linear in the expanded condition EC of the support arms 81 .

Reference list

1 elongated medical device

2 elongated body

3 distal portion

4 distal end

5 proximal portion

6 tip electrode

7 handle

7a first handle part

7b second handle part

8 ground electrode

9 arrow

1 0 direction

1 1 further elongated medical device

1 2 data line

1 3 fluid supply line

1 4 sub-zone of data output screen / data output screen

1 5 data processing and control unit

1 6 data output unit

1 7 fluid supply

1 8 fluid opening

19 fluid channel

21 ring element

23 first channel

24 inner shaft-member

25 steering member (axially movable)

26 guide channel

27 steering wires

28 inner tube

29 outer tube hul l (distal portion) (electro-anatomic) data arrows

a circular arrow

b ci rcular arrow

ci rcular arrow ci rcular excitation patterns (rotors) elastic element (helical spri ng) flexible tube first position of 25

direction of fluid flow second position of 25 electrode assembly/mapping electrode assembly support arms

a proximal part

b distal part

c central part

electrodes/mappi ng electrodes

spiral structure

spiral arms

PCB layers

(shape memory metal) strands

second channels

mappi ng electrode cables

a ablation electrode cables

electric li nes

electronics unit 91 electronic elements / ASIC^'s 92 operational amplifiers

93 multiplexer

94 analog-digital converter

1 1 0 further elongated medical device 21 0 further elongated medical device 31 0 further elongated medical device

A longitudinal axis

C center of symmetry

EC expanded condition (of 80) F Force

P Plane

UC unexpanded condition (of 80) x distance

distance

Claims

1 . ) An elongated medical device (1 ) suitable for intravascular insertion, said device compris- ing a flexible elongated body (2) having a distal portion (3) with a distal end (4) and a proximal portion (5), and an electrode assembly (80) located at the distal portion (3) and including at least two support arms (81 ), each support arm (81 ) having a proximal part (81 a), a distal part (81 b) and a central part (81 c) between the proximal part (81 a) and the distal part (81 b), a plurality of electrodes (82) arranged on the at least two support arms (81 ), the at least two support arms (81 ) being configured to have an unexpanded condition (UC), where the at least two support arms (81 ) fit closely along a portion of the elongated body (2), and to have an expanded condition (EC), where at least a part of each of the at least two support arms (81 ) project away from the elongated body (2), characterized in that, at least the central parts (81 c) of the at least two support arms (81 ) are wound in a spiral in the expanded condition (EC) of the support arms (81 ), forming a spiral structure (83) with at least two spiral arms (84) and with the distal end (4) being located in a center of symmetry (C) of the spiral structure (83).

2. ) Medical device (1 ) according to claim 1 , characterized in that, the electrode assembly (80) includes a number of 2 plus n support arms (81 ), whereby n equals 2 to 30, preferentially 2 to 22, more preferentially 2 to 1 4.

3. ) Medical device (1 ) according to claim 1 or 2, characterized in that, the distal portion (3) defines a longitudinal axis (A), the center of symmetry (C) of the spiral structure (83) is located in the longitudinal axis (A) and the spirally wound parts of the support arms (81 ) lie in a plane (P) that intersects the longitudinal axis (A) perpendicularly.

4. ) Medical device (1 ) according to any one of claims 1 to 3, characterized in that, the electrodes (82) are located on the central parts (81 c) of each of the support arms (81 ) and that the electrodes (82) are lying in or parallel to the plane (P) in the expanded condition (EC ) of the support arms (81 ).

5. ) Medical device (1 ) according to any one of claims 1 to 4, characterized in that, the distal parts (81 b) of the support arms (81 ) being attached to the distal portion (3) adjacent the distal end (4) and the proximal parts (81 a) of the support arms (81 ) beingicou- pled to a steering member (25) located on an end of the proximal portion (5) facing the distal portion (3).

6.) Medical device (1 ) according to any one of claims 1 to 5, characterized in that, the steering member (25) is adapted to be moved back and forth between a first position (60) and a second position (70), wherein a movement from the first position (60) to the second position (70) is in direction of the distal portion (3) in order to dislocate the support arms (81 ) from their unexpanded condition (UC), where the at least two support arms (81 ) fit closely along a portion of the elongated body (2), to their expanded condition (EC), where at least the central parts (81 c) of the at least two support arms (81 ) are spirally wound and

wherein a movement from the second position (70) to the first position (60) is in a direction away from the distal portion (3) in order to dislocate the support arms (81 ) from their expanded condition (EC) back into their un-expanded condition (UC).

7. ) Medical device (1 ) according to any one of claims 1 to 6, characterized in that, each support arm (81 ) comprises a strand (86) formed of a shape memory metal and a PCB layer (85), whereby the PCB layer (85) carries the electrodes (82) and the electric lines (89) for contacting the electrodes (82) electrically.

8. ) Medical device (1 ) according to claim 7, characterized in that,

in each of the shape memory metal strands (86) a spiral arm shape is memorized.

9.) Medical device (1 ) according to any one of claims 1 to 8, characterized in that, on each of the support arms (81 ) a number of 8 to 30 electrodes (82) is disposed.

1 0.) Medical device (1 ) according to claim 9, characterized in that, on each of the support arms (81 ) a number of 8 to 1 8 electrodes (82) is disposed.

1 . ) Medical device (1 ) according to any of claims 1 to 10, characterized in that, the electrodes (82) are gold plated. 2. ) Medical device (1 ) according to any one of claims 1 to 1 1 , characterized in that, the surface size of an electrode (82) is between 0,01 mm² and 0,25 mm².

3.) Medical device (1 ) according to any one of claims 1 to 12, characterized in that, two adjacent electrodes (82) on an individual support arm (81 ) are arranged in a distance (x) to each other, wherein the distance (x) is between 2 mm and 9 mm, preferably between 2.5 mm and 4.5 mm.

4.) Medical device (1 ) according to any one of claims 1 to 1 3, characterized in that, two adjacent electrodes (82) on two adjacent support arms (81 ) are arranged in a distance (y) to each other, wherein the distance (y) is between 2 mm and 9 mm, preferentially between 2.5 mm and 4.5 mm.

1 5.) Medical device (1 ) according to any one of claims 1 3 to 14, characterized in that, the distance (x) and the distance (y) are equal within a maximum tolerance in a range of up to +/- 0,5 mm.

1 6.) Medical device (1 ) according to any one of claims 1 to 1 5, characterized in that, the electrodes (82) on the support arms (81 ) being electrically connected to at least one electronic element (91 ) of an electronics unit (90) disposed at the distal portion (3) adjacent the distal end (4).

1 7.) Medical device (1 ) according to any one of claims 1 to 1 6, characterized in that the at least on electronic element (91 ) is configured to process and digitize analog signals received from the electrodes (82).

1 8.) Medical device (1 ) according to any one of claims 1 to 1 7, characterized in that the at least one electronic element (91 ) is an ASIC which comprises one or more operational amplifiers (92), at least one multiplexer (93) and at least one analog-digital converter (94). Medical device (1 ) according to any one of claims 1 to 1 8, characterized in that the electronics unit (90) with the at least one electronic element (91 ) is adapted to be connected to a data processing and control unit (1 5) that is configured to process digitized electrode measurement data and to output data for visualizing muscular rotors of a patient on a data output unit (1 6).

Medical device (1 ) according to any one of claims 1 to 1 9, characterized in that it is formed as a catheter for exploration or treatment of a vessel, organ or other body cavity.

A Method of making an elongated medical device (1 ) suitable for intravascular insertion, especially a method of making an electrophysiological mapping catheter, comprising:

providing a set of at least 2 strands consisting of shape memory metal and memorizing a spiral arm form in each of the strands of shape memory metal,

stretching each of the strands and attaching an electrode carrying PCB layer to each of the strands to form support arms (81 )

mounting the ends of the proximal parts of the support arms to an axially movable steering member and locating the axially movable steering member at an end of a proximal portion of a pre-assembled part of the elongated device,

mounting the ends of the distal parts of the support arms to a distal portion (3) of a pre-assembled part of the elongated device adjacent to the distal end (4) electrically connecting the PCB's to at least one electronic element arranged at the distal portion (3) of the pre-assembled part of the elongated device adjacent to the distal end (4).