WO2017041891A1

WO2017041891A1 - Elongated medical device suitable for intravascular insertion

Info

Publication number: WO2017041891A1
Application number: PCT/EP2016/001514
Authority: WO
Inventors: Peter Ruppersberg
Original assignee: Ablacon Inc.
Priority date: 2015-09-07
Filing date: 2016-09-07
Publication date: 2017-03-16

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 a mapping electrode assembly (80) located at the distal portion (3) having a plurality of electrodes (82), wherein the electrodes (82) are electrically connected to at least one electronic element (91 ) of an electronics unit (90) that is disposed in the medical device (1).

Description

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, a mapping electrode assembly located at the distal portion having a plurality of electrodes. 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.

The present invention relates also to a method of analyzing electrophysiological data, especially action potential data.

The present invention especially relates to an elongated medical device suitable for intravas- cular insertion with individual features of claim 1 .

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 excita- tion patterns (rotors), in the left atrium that induce a high^' frequency fibrillation through their re-entry mechanism. Those rotors have the character of small action potential cyclones of 2 to 3 cm² in size. The likelihood of occurrence of those rotors and the frequency of pathological action potential generation in the pulmonary veins increases with fibrotic structural changes and certain modifications of ion channel expression patterns in atrial cells with age. The only potentially 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 circles.

Today the use of catheter ablation like open heart surgery is still limited by the potentially fatal risk of some severe side effects associated with the procedure: When the integrity of the atrial wall is destroyed by too intense ablation, perforations of the atrial wall into the pericardium or fistulas into the esophagus can have severe to deadly outcomes. The alteration of the endocardial cells on a larger surface can initiate clotting in the treated atrium which may lead to deadly strokes. That is why the procedure requires full anticoagulation. Last but not least, if the intensity of the ablation is kept too low to avoid those side effects in 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 allow to better control the catheter positioning pressure which has an influence on the intensity 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 splines for guiding a plurality of exposed electrodes, the splines having proximal portions, distal portions and medial portions therein between; a proximal anchor for securely affixing the proximal portions of the splines; the proximal anchor being secured at the distal end of the first elongate tubular member; a distal tip consisting essentially 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 i n the area of the equator of the system in its radially expanded shape. US 7,081 , 1 1 4 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 flattened 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 tension/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 disad- vantage 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 millimeters. 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 201 0/0094274 A1 discloses a sensor catheter in the form of an adjustable corkscrew design, 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 wil l 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 correlated 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 which has an improved applicability and allows for an improved electrode mapping of tissue areas.

These and other objects of the present invention are accomplished by providing an elongated medical device suitable for intravascular insertion wherein the electrodes are electrically con- nected to at least one electronic element of an electronics unit that is disposed in the medical device. The electronic element of the electronic unit disposed in the medical device itself has the advantage, that some processing of the electrode measurement data can already be performed in the elongated medical device. This improves the quality of electrode mapping due to enhanced and seed up data processing and will further reduce noise and the sensitivity to electrical interference. Also, the interface with the data processing and control unit, such as a standard PC will be less complex and fail-safe. The interface could be a standard USB interface or other present or future standard interface. Further, the at least one electronic element may be disposed at the distal portion adjacent to the distal end, which will reduce the lengths of cables and/or data lines from each electrode to the electronic element.

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 and/or interfaces 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 spirally 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 visual- izing 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 electronics unit with the at least one electronic element forms a microcomputer for digital processing of digitized analog data. Accordingly, some processing of the digitized data may occur in the electronic element such that pre-processed digital data may be communicated to the data processing and control unit. Processing of data by the electronic element may include but are not limited to grouping of data, data statistics and normalization of data.

Preferably, the plurality of electrodes is arranged on at least two support arms, the at least two support arms being configured to have an unexpanded condition, where the at least two sup- port 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. 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 mapping screen that has a spiral structure with at least two spiral arms and with the distal end being located in the center of symmetry of the spiral structure.

In this embodiment, the force sensor is located in the area of the center of symmetry of the spiral structure (and respectively of the mapping electrode assembly) and is configured to sense a force applied to said distal end. The advantage of the central disposition of the force sensor in respect to the spiral structure is, besides from the before mentioned advantages of a force sensor in general, the easy navigation and positioning achieved by this geometry. Again, the force sensor is used to verify that the mapping electrode assembly is touching the inner surface of the atrium. Once a rotor in a muscular tissue could be identified, and once the spirally structured electrode array has been centered in respect to this rotor, the tip/distal end of the elongated medical device is automatically centered together with the electrode array and so is the force sensor centered. When the correct press-on force for ablation has been detected by the force sensor, then an ablation of the body tissue can be initiated by an ablation tip electrode, thus ablating the center of the rotor 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 electrodes 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.

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 condi- tion 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 axial ly 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 advantageous embodiment of the invention, a force sensor is disposed within said flexible elongated body proximate said distal end. With the force sensor present in the device, press on forces of the device to the body tissue may be associated with the electrode mapping data, which will especially be of importance when the device is also capable of ablating body tissue e.g. by means of ablation electrodes present at the tip and/or distal portion of the elongated medical device.

In a further preferred embodiment of the invention, the force sensor is located in the area of the center of symmetry of the spiral structure (and respectively of the electrode assembly) and is configured to sense a force applied to said distal end. The advantage of the central disposition of the force sensor in respect to the spiral structure is, besides from the before mentioned advantages of a force sensor in general, the easy navigation and positioning achieved by this geometry. The force sensor is used to verify that the mapping electrode assembly is touching the inner surface of the atrium. Once a rotor in a muscular tissue could be identified, and once the spirally structured electrode array has been centered in respect to this rotor, the tip/distal end of the elongated medical device is automatically centered together with the electrode array and so is the force sensor centered. When the correct press-on force for ablation has been detected by the force sensor, then an ablation of the body tissue could be initiated by an ablation tip electrode, thus ablating the center of the rotor structure. Advantageously, the at least one electronic element is configured to process and digitize analog signals received from the force sensor. Due to this advantageous data processing and digitalization 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 further reduced in number. Digitized data of the force sensor may even be communicated to the external data processing unit via the same data line and/or interface as the digitized data of the mapping electrodes.

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 1 8 electrodes is disposed on each of the support arms allowi ng for an electrode array of 1 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 still 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.

I n 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 still 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 i n 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.

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.

A favourable method of analyzing electrophysiological data, especially action potential data, comprises the steps of:

measuring electrophysiological data with a plurality of mapping electrodes (82) disposed at a distal end of an elongated medical device,

transmitting the action potential data from the plurality of mapping electrodes (82) to a data processing and control unit (1 5),

performing an optical flow analysis of the action potential data and generate series of vector data representing the average speed of movement of clusters of the action potentials,

displaying the vector data on a data output screen of the data output unit. By means of this inventive method it is possible for the first time to visualize the direction of rotation of rotors and to localize them in the atrium of the heart.

In a favourable embodiment, the action potential data measured by the mapping electrodes are digitized in an electronic unit disposed within the elongated medical device before being transmitted in form of digital data to the data processing and control unit. The advantage is that data transmission and the interface between the medical device and the data processing and control unit will be fail-safe and fast.

Advantageously, the action potential data is analyzed with an algorithm called optical flow analysis which estimates the average speed and direction of action potential propagation at a certain electrode. This yields vector data which displayed on the data output screen in form of data arrows, the total of the data arrows displayed represent action potential wave maps. In these action potential wave maps, rotors may easily be identified so that ablation may immediately be initiated so that rotors may be ablated on the spot.

Optical flow analysis may be performed using a data analysis method chosen from the group consisting of phase correlation method, block-based method, discrete optimization methods and differential methods of estimating optical flow including the Lucas-Kanade method, the Horn-Schunck method, the Buxton-Buxton method and the Black-Jepson method or any variations thereof. Preferably, the Horn-Schunck method is used. Such optical flow analysis allows for a data integration time in the range between 1 00 ms and 10 seconds.

Further features of the invention, its nature and various advantages will become more apparent 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. l 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. l 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, ex- panded 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. 1 0 according to the marking Xa in Fig. 1 0;

Fig. 1 1 is a top view of a still further embodiment of the elongated medical device in 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. 12 is a top view of a still 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 still 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. 13 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. 14b 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 intravascular insertion, such as a catheter for exploration or treatment of a vessel, organ or other body cavity which includes an electrode assembly for electro-anatomic mapping of cardiac or vessel areas or the like medical apparatus. The medical device has a force sensor which could be formed as a 3 D optical 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 in three dimensions. Such an optical force sensor is e.g. disclosed in the parallel patent application PCT/EP2015/001097 (herewith incorporated by reference). In operation of the medical device, the force sensing ability may be used periodically to measure the contact forces at certain points, or, alternatively, it may be used to continuously monitor such contact forces to support the operation of the medical device. The electrode assembly may be used to map circular excitation patterns (rotors), e.g. of the left atrium of the heart, as will be described in more detail in the following. 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 Fibri llation and other hearth rhythm diseases like Atrial Flutter, Accessory Pathways or Ventricular Tachycardia. The elongated medical device 1 comprises an elongated body 2, which is only partly shown in Figures l 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 i nner shaft-member 24 member there are arranged a number of channels which include a first channel 23, through which the force sensor cable 22 is guided along the elongated body 2 up to the force sensor 20, 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 Ί 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 13, which may be connected to a fluid supply 1 7 (see Fig. 1 d). This fluid supply line 1 3 is in fluid-guiding connec- tion 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.

The distal portion houses towards its distal end 4 a force sensor assembly 20 / force sensor, preferably an optical force sensor such as described in co-pending patent application PCT/EP201 5/001 097 of the applicant. The force sensor assembly comprises an elastic ele- ment 51 , which is formed as a helical spring that has a metal core and an outer rim, which is formed by an isolating plastic material. By means of the elastic element 51 , a first and a second part of the force sensor are moveably connected with each other, whereby this connection need not be a fixed connection. Radially outwardly of the elastic element 51 , the tip 6 and the ring element 21 which carries at least a part of the force sensor 20 are fluid-tightly connected by the flexible tube 56.

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 controlled.

The electrode assembly 80 / mapping electrode assembly is located at the distal portion 3 and comprises in the embodiment of Figures l 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 l 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 1 8 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 elec- trade 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 close to the force sensing assembly 20 (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 electronics unit 90 with the at least one electronic element 91 forms a microcomputer for digital processing of digitized analog data. 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 at least one electronic element 91 is in this embodiment also configured to process and digitize analog signals received from the force sensor 20 / force sensing assembly.

The operational amplifiers 92 acquire AC inputs from the electrodes 82 on four wires / electric lines 89 with 1 00 kilo 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 14 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 jointly with the force sensor data of force sensing assembly 20.

The force sensing assembly 20, 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 force sensor assembly 20 and the electrodes 6, 8. Data processing and control unit 1 5 processes electrode mapping data from the electrode assembly and sensor data received from the force sensor assembly 20 and outputs mapping data and force sensor 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 force sensor cable 22, mapping electrode cables 88 and ablation electrode cables 88a. Data received by the data processing and control unit 1 5 are in a digital format due to prior digi- talization by the analog-digital converter 94 in the electronic element(s) 91 . Digitized data may be pre-processed to a certain extent in the electronic element 91 . Pre-processing may include but is not limited to the grouping of data, data statistics and normalization of data.

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 1 4a 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 the force sensing assembly 20 of the elongated medical device 1 or catheter has 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 travelling 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 1 00 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 pat- tern or cluster has a length of about four to five electrode distances x, y. The circular excitation pattern 45 is recorded every 1 0 ms and visualized on a screen or sub-zone 14 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 measurement 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 14 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. 1 4a, 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 facility (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, an optical flow detector that performs an optical flow analysis, and a 3 D engine. When the tip electrode 6 / the distal end 4 of the elongated medical device 1 touches the atrial wall the force sensor 20 triggers the integration of images coming from the image generator by the optical flow detector. The optical flow detector determines the movement of the action potentials represented by clusters in the images and integrates this action potential data into an action potential wave map once per second. Those maps are relatively time inde- pendent since the action potential speed values do not largely vary with time. Rotors and break-through points are easily visible in those maps (see again Figs. 1 4a and 1 4b).

Once per second the action potential wave maps are handed over to the 3D engine together with the 3D coordinates of the mapping screen position. The 3D engine builds a model of the atrium textured with the action potential wave maps. The average action potential amplitudes are used for displaying structural changes of the atrium like fibrosis and are shown by slight variations of background color. A single touch of the atrial wall of one second creates 1 9 cm2 of action potential wave map. If a larger atrium has 100 cm2 in endocardial wall surface a complete mapping requires that the elongated medical device 1 touches everywhere for at least one second and with a correct angle and force F vector. The minimum would be about five recordings to cover almost the full surface. There is no harm if the areas of recordi ng are overlapping. After the investigator has obtained a first picture of the situation RF (radio frequenzy) ablation via electrodes 6, 8 can already be started. The visualization of the action potential data on the display or data output screen 1 4 is from inside the atrium and the center of the display is always the tip electrode 6 respectively the distal end 4. Upon an F ablation series has been performed the generator tells the 3D engine to change the color of the existing action potential wave map to a colour indicating the result of ablation, resets the optical flow detector and the mapping screen is prepared to create a new map of the atrium in order to have therapy control. If the resulting action potential wave map has fundamentally changed or atrial fibrillation has stopped the investigator may decide to continue ablation based on the previous rotor map now in pink or to reinvestigate the rotor map after this ablation series eventually after artificially restarting atrial fibrillation through pacing with the coronary sinus catheter.

The system automatically stores every individual map created in between ablation series for documentation purposes. Action potential wave maps are created by calculating the optical flow in an optical flow analysis. Optical flow is a mathematical concept developed in the 1 940s that determines motion of objects, surfaces, and edges in a visual scene. Sequences of ordered images allow the estimation of motion as either instantaneous image velocities or discrete image displacements. The intensity I (x, y, t) will have moved by Δ x, Δ y and Δ t between the two image frames.

Examples of methods to perform optical flow analysis are: Phase correlation methods, (inverse of normalized cross-power spectrum), Block-based methods (minimizing sum of squared differences or sum of absolute differences, or maximizing normalized cross-correlation), dis- crete optimization methods (the search space is quantized, and then image matching is addressed through label assignment at every pixel, such that the corresponding deformation minimizes the distance between the source and the target image. The optimal solution is often recovered through Max-flow min-cut theorem algorithms, linear programming or belief propagation methods), differential methods of estimating optical flow ( based on partial derivatives of the image signal and/or the sought flow field and higher-order partial derivatives), such as: Lucas-Kanade method (regarding image patches and an affine model for the flow field), Horn-Schunck method (optimizing a functional based on residuals from the brightness constancy constraint, and a particular regularization term expressing the expected smoothness of the flow field), Buxton-Buxton method (based on a model of the motion of edges in image sequences), Black-Jepson method (coarse optical flow via correlation) and variations thereof.

In Fig. 1 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 20 as has been described before. 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 electrode 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 ref- erence numerals and functions not described in the following text, reference is made to the description of Figs, l a to 9 which is herewith incorporated by reference.

The embodiment of Figs. 1 0 and 10a 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.

I n 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 1 2a display a further embodiment of the elongated medical device 210. 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 1 2a 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. 13 to 13a another embodiment of the elongated medical device 310 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

12 data line

13 fluid supply line

14 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

1 9 fluid channel

20 force sensing assembly/ force sensor

21 ring element

22 force sensor cable

23 first channel

24 inner shaft-member

25 steering member (axially movable)

26 guide channel

27 steering wires

28 inner tube

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

a circular arrow

b circular arrow

circular arrow circular excitation patterns (rotors) elastic element (helical spring) 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/mapping electrodes

spiral structure

spiral arms

PCB layers

(shape memory metal) strands

second channels

mapping electrode cables

a ablation electrode cables

electric lines

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 a mapping electrode assembly (80) located at the distal portion (3) having a plurality of electrodes (82),

characterized in that, the electrodes (82) are electrically connected to at least one electronic element (91 ) of an electronics unit (90) that is disposed in the medical device (1 ).

2. ) Medical device (1 ) according to claim 1 , characterized in that, the at least one electronic element (91 ) is disposed at the distal portion (3) adjacent the distal end (4).

3. ) Medical device (1 ) according to claim 1 or 2, characterized in that, the at least one electronic element (91 ) is configured to process and digitize analog signals received from the electrodes (82).

4. ) Medical device (1 ) according to any one of claims 1 to 3, 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).

5.) Medical device (1 ) according to any one of claims 1 to 4, 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).

6.) Medical device (1 ) accordi ng to any one of claims 1 to 5, characterized in that, the electronics unit (90) with the at least one electronic element (91 ) forms a microcomputer for digital processing of digitized analog data.

7. ) Medical device (1 ) according to any one of claims 1 to 5, characterized in that, the electrode assembly (80) is configured to have an unexpanded condition (UC), where the electrode assembly (80) is stored at a portion of the elongated body (2), and to have an expanded condition (EC), where the electrode assembly (80) forms a at least two dimensional mapping screen that has a center of symmetry (C).

8. ) Medical device (1 ) according to any of claims 1 to 5 and 7, characterized i n that, the plurality of electrodes (82) is arranged on 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 (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 ), formi ng a mapping screen that has a spi ral structure (83) with at least two spi ral arms (84) and with the distal end (4) bei ng located in the center of symmetry (C) of the spi ral structure (83).

9.) Medical device (1 ) according to any one of claims 1 to 6 and 8, characterized i n that, the electrode assembly (80) i ncludes a number of 2 plus n support arms (81 ), whereby n equals 2 to 30, preferentially 2 to 22, more preferential ly 2 to 1 4.

1 0.) Medical device (1 ) accordi ng to any one of claims 1 to 6 and 8 to 9, characterized i n 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.

1 1 .) Medical device (1 ) according to any one of claims 1 to 6 and 8 to 10, 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 ).

12.) Medical device (1 ) according to any one of claims 1 to 6 and 8 to 1 1 , characterized in that, the distal parts (81 b) of the support arms (81 ) being attached to the distal portion (3) ad- jacent the distal end (4) and the proximal parts (81 a) of the support arms (81 ) being coupled to a steering member (25) located on an end of the proximal portion (5) facing the distal portion (3).

1 3.) Medical device (1 ) according to any one of claims 1 to 6 and 8 to 1 2, 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).

14.) Medical device (1 ) according to any one of claims 1 to 6 and 8 to 1 3, 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.

1 5.) Medical device (1 ) according to claim 1 4, characterized in that,

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

1 6.) Medical device (1 ) according to any one of claims 1 to 6 and 8 to 1 5, characterized in that, a force sensor (20) is disposed within said flexible elongated body (2) proximate said distal end (4).

1 7.) Medical device (1 ) according to claim 1 6, characterized in that, the force sensor (20) is located in the area of the center of symmetry (C) of the spiral structure (83) and is configured to sense a force (F) applied to said distal end (4).

18. ) Medical device (1 ) according to claim 1 6, characterized in that, the at least one electronic element (91 ) is configured to process and digitize analog signals received from the force sensor (20).

1 9. ) Medical device (1 ) according to any one of claims 1 to 6 and 8 to 1 7, characterized in that, on each of the support arms (81 ) a number of 8 to 30 electrodes (82) is disposed.

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

21 . ) Medical device (1 ) according to any one of claims 1 to 6, 8 to 1 7 and 1 9 to 20, characterized in that, the surface size of an electrode (82) is between 0,01 mm² and 0,25 mm².

22. ) Medical device (1 ) according to any one of claims 1 to 6, 8 to 1 7 and 1 9 to 21 , 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.

23. ) Medical device (1 ) according to any one of claims 1 to 6, 8 to 1 7 and 1 9 to 22, 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.

24. ) Medical device (1 ) according to any one of claims 15 to 6, 8 to 1 7 and 1 9 to 23, 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.

25. ) Medical device (1 ) according to any one of claims 1 to 6, 8 to 1 7 and 1 9 to 24, characterized in that it is formed as a catheter for exploration or treatment of a vessel, organ or other body cavity.