Abstract:
A multipolar electrode arrangement having a plurality of electrodes ( 14, 14′, 14 ″) with an electrical feed line, wherein the electrodes ( 14, 14′, 14 ″) are connected to an electrode carrier ( 10 ) which is adapted to be insertable together with the electrodes ( 14, 14′, 14 ″) into the lumen of a catheter.

Description:
The invention concerns a multipolar electrode arrangement having a plurality of electrodes with an electrical feed line. 
     BACKGROUND OF THE ART 
     A particular area of use of multipolar electrode arrangements is the output of electrical signals to body tissue, in particular cardiac tissue, and picking up electrical signals from the heart. Contraction and relaxation of the cardiac muscles is controlled by electrical signals which pass through the cardiac tissue in an excitation front. Knowledge about signal propagation in the heart is an aspect of great significance, in terms of diagnosis and therapy of heart diseases. U.S. Pat. No. 5,921,923, to Kuck (Jul. 13, 1999), discloses a multipolar electrode arrangement in which the electrodes are arranged in such a way that not only the occurrence of events but in addition also the direction and speed of stimulus conduction can be detected. 
     For that purpose the poles are spatially arranged in relation to each other on the catheter in such a fashion that respective pairs thereof so-to-speak define a co-ordinate system. Other electrode arrangements are to be found in U.S. Pat. No. 5,385,146 to Goldreyer (Jan. 31, 1995) and U.S. Pat. No. 5,476,503 to Yang (Dec. 19, 1995). 
     SUMMARY OF THE INVENTION 
     That object is attained by an electrode arrangement of the kind set forth in the opening part of this specification, in which the electrodes are connected to an electrode carrier which is adapted to be insertable together with the electrodes into the lumen of a catheter. 
     An electrode arrangement of that kind permits simplified manufacture of any pole configurations in particular on a single lead electrophysiology catheter. In that respect the configuration of the electrodes is predetermined by the electrode carrier. The electrode carrier with the electrodes secured thereto can be pre-assembled and then inserted with electrical feed lines into a catheter tube. 
     A preferred electrode arrangement is one in which the electrode carrier is elastically deformable, more particularly preferably substantially in a first plane while it is substantially stiffer in a second plane which is perpendicular to the first plane. For that purpose the electrode carrier preferably includes a leaf spring element of preferably flat cross-sectional profile. 
     The leaf spring element is preferably of an electrically insulating nature and is preferably of a flat cross-sectional profile. In a preferred embodiment the electrode carrier and in particular the leaf spring element at least partially comprise a polymer. The electrode carrier can then be in the form of an injection molding in a particularly desirable fashion. 
     The advantages of an electrode arrangement with such an electrode carrier are pertinent in particular when the electrode carrier is connected at its distal end to a control means which is guided longitudinally slidably along the electrode carrier relative thereto so that deflection of the electrode carrier can be effected at the distal end thereof by longitudinal displacement of the control means relative to the electrode carrier. It is possible in that way to provide an electrophysiology catheter which can be targetedly and specifically deflected in cavities such as for example the atrium or ventricle of a heart and guided into a defined direction in order to be able to pick up signals at defined locations in the heart. For that purpose the catheter tip can be provided with marking means which make it possible to locate the catheter tip from outside the body by means of imaging processes. 
     Preferably, the electrode arrangement includes a catheter having a lumen which is adapted to receive the electrode carrier, wherein the catheter has openings which extend from the lumen and which are of such an arrangement and configuration that the electrodes connected to the electrode carrier can pick up electrical signals outside the catheter. In a preferred alternative configuration, the openings can be disposed in the peripheral surface of the catheter and in particular of a catheter tube, more specifically in such a way that a corresponding opening is provided for each individual electrode. Alternatively however the electrode carrier can also be designed in such a way that as a whole it projects out of a central opening at the distal end of the catheter or catheter tube. 
     A further preferred electrode arrangement is one in which the electrodes are arranged in mutually displaced relationship in the longitudinal and peripheral directions of the catheter in such a way as to afford at least one electrode matrix which makes it possible to determine the direction and speed of a signal from the time displacement with which the signal reaches various ones of the electrodes. In that respect, an adequate spacing not only in respect of the center points of the surfaces of the individual electrodes but between the electrode surfaces is advantageous in terms of determining the speed of the stimulus conduction. 
     In the above-mentioned electrode arrangement an electrode matrix preferably includes at least three electrodes, wherein the center points of the surfaces of the electrodes of an electrode matrix are preferably arranged at the corners of notional triangles or quadrangles. 
     As an alternative to the electrodes being made from metal, which affords the advantage of the high level of conductivity of metal, a particularly preferred electrode arrangement is one in which the electrodes include conductive plastic material. 
     In an advantageous embodiment, such an electrode arrangement makes it possible to arrange the electrodes in depressions in a non-conductive base material, in particular the insulating leaf spring element. The depressions can be produced for example with a high degree of precision by means of a laser beam so that even small microstructures can be produced. The non-conductive base material can be a component part of the electrode carrier. 
     In principle electrodes of conductive plastic material are known from U.S. Pat. specifications Nos. 5,433,742 and 5,029,585. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in greater detail by means of embodiments with reference to the Figures in which: 
     FIG. 1 is a side view of an electrode carrier together with electrodes and feed lines, 
     FIG. 2 is a plan view of the electrode carrier of FIG. 1, 
     FIG. 3 shows the electrode carrier of FIGS. 1 and 2, inserted into a single-lumen tube of an electrophysiology catheter, 
     FIG. 4 is a view similar to FIG. 2 of an electrode carrier with an alternative electrode arrangement, and 
     FIG. 5 shows an electrode carrier with a second alternative electrode arrangement. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows an electrode carrier  10  whose essential component is an insulating leaf spring element  12 . Secured to the insulating leaf spring element  12  are two electrodes  14  by the electrodes  14  being glued or riveted to the leaf spring element  12 . A respective electrical feed line  16  is associated with each electrode  14 . The electrodes  14  comprise platinum, iridium or electrical conductive plastic material. 
     FIG. 2 is a plan view of the electrode carrier of FIG.  1  and therewith the arrangement of the electrodes  14  on the insulating leaf spring element  12 . The electrodes  14  are arranged at a spacing from each other on the longitudinal axis of the insulating leaf spring element  12 . The spacing of the electrodes  14  from each other means that a signal with a component of propagation in the longitudinal direction of the leaf spring element reaches the one electrode  14  prior to the other. In that way it is possible to determine the speed component of signal propagation in the longitudinal direction of the leaf spring element from the time delay with which the signal is detected by the two electrodes  14 . 
     In FIG. 3, the electrode carrier  10  shown in FIGS. 1 and 2 is inserted into a single-lumen tube  20  of an electrophysiology catheter. The tube has two openings  22  which are provided to receive the electrodes  14  so that they project outwardly from the lumen of the tube in order to be able to pick up electrical signals outside the tube. 
     In addition, secured to the distal end  24  of the leaf spring element  12  is a control mechanism  26  which can be formed for example by a wire which, with the exception of the location of its fixing to the distal end  24  of the leaf spring element  12 , is displaceable relative to the leaf spring element  12  in the longitudinal direction thereof. In that way, the electrophysiology catheter can be specifically and targetedly deflected laterally in the region of the leaf spring element  12  in the manner of per se known controllable guide wires. 
     The electrode carrier design implemented in FIGS. 1 through 3 permits a simple arrangement of multipolar electrodes. A great advantage lies in simple handling in terms of production. The electrode carrier together with the electrodes  14  can be completely pre-assembled as a unit and then fitted into the single-lumen tube  20 . The insulating leaf spring element  12  is of a rectangular cross-sectional shape which, in a plane extending through the longitudinal axis of the leaf spring element  12 , provides for a high level of lateral stability while it permits elastic deflection of the leaf spring element  12  in a plane which is perpendicular to the first plane. 
     FIGS. 4 and 5 each show respective alternative electrode arrangements. In FIG. 4 a total of eight electrodes  14 ′ are arranged on the leaf spring element  12 ′. Four electrodes  14 ′ in each case are combined to form a respective electrode matrix  30 . The electrodes  14 ′ of an electrode matrix are arranged at a spacing from each other in such a way that the center points of their surfaces lie at the corners of a notional quadrangle. That notional quadrangle is of mirror-image symmetrical configuration in relation to those two axes which connect the respectively non-adjacent corners of the quadrangle. Those two axes moreover are perpendicular to each other and one of those axes extends in the direction of the longitudinal axis of the spring element  12 . The notional quadrangle is shown in broken line in FIG.  4  and the two axes connecting the corners are shown in dash-dotted lines. 
     In FIG. 5 the two electrode matrices  30 ′ are each formed by three electrodes  14 ″. The three electrodes  14 ″ of an electrode matrix  30 ′ are not all of the same surface area, like the electrodes  14 ′ of FIG.  4 . On the contrary, one of the electrodes  14 ″ is of twice the surface area as the other two electrodes  14 ″ of the same electrode matrix  30 ′. The two smaller electrodes  14 ″ are arranged in side-by-side relationship at both sides of the longitudinal axis, shown in broken line, of the leaf spring element  12 ″. The third larger electrode  14 ″ is arranged adjacent to the two smaller electrodes  14 ″ in the longitudinal direction of the leaf spring element  12 ″. 
     The electrode arrangements in FIGS. 4 and 5 have a series of common features: the individual electrodes  14 ′,  14 ″ of an electrode matrix  30 ,  30 ′ are at a spacing from each other which is of sufficient size so that an advancing signal reaches one or two of the electrodes of the electrode matrix earlier than the other electrodes. Both the direction of propagation and also the speed of propagation of the signal can be determined from the time displacement with which a signal reaches the individual electrodes of an electrode matrix  30 , and from the arrangement of the electrodes within the electrode matrix  30 ,  30 ′. 
     In addition, each of the electrode arrangements shown has two electrode matrices  30 ,  30 ′ which are at a substantially greater spacing from each other in the longitudinal direction of the leaf spring element  12 ′,  12 ″, than the spacing of the electrodes  14 ′,  14 ″ of an electrode matrix  30 ,  30 ′ from each other. 
     The electrodes  14 ′ and  14 ″ of the electrode arrangements shown in FIGS. 4 and 5 are formed by depressions in the insulating leaf spring element  12 ′,  12 ″, which are filled with conductive plastic material. To produce such electrodes, firstly for example a laser beam is used to produce the depressions in the insulating leaf spring element  12  or  12 ′. This can be done with a very high degree of accuracy. Those depressions are then filled with conductive plastic material. The electrodes produced in that way involve a high level of accuracy. At the same time the manner of manufacture involved is particularly simple. This kind of electrode configuration can therefore also be used in a different context and is not limited to the uses in connection with the described electrode carrier.