DE102016011799A1 - Ablation catheter and method for performing ablation - Google Patents

Abstract

An ablation catheter (1) has a catheter head (100; 200; 300; 400; 500; 600) at the distal end (110; 210; 310; 410; 510; 610) thereof a plurality of electrodes (120, 120; 220 , 231, 232, 320, 330, 420, 430, 531, 532, 620, 630), each of the electrodes (120, 130, 220, 231, 232, 320, 330, 420, 430, 531, 532 ; 620, 630) is individually controllable for measuring an electrical signal and / or for ablation of tissue. The catheter head (100; 200; 300; 400; 500; 600) is formed at least partially from an elastic polymer.

Description

The invention relates to an ablation catheter, a method of ablation, and the use of an ablation catheter for performing ablation on tissue.

The invention is in the field of medical technology, in particular the treatment of cardiac arrhythmias by radiofrequency ablation (abbreviated as: RF ablation) or cryoablation. The aim of ablation is the detection and sclerotherapy of arrhythmogenic heart tissue. In RF ablation, a small scar can be placed in the heart tissue locally to cure a rhythm disorder.

One problem with RF ablation is that the shape and quality of the scar is not well known immediately after RF ablation. This prevents the detection of only seemingly satisfactory treatment results. Poor treatment results may arise due to only temporarily altered tissue properties, especially in the marginal regions of the scar, as well as by an uneven overlay of multiple punctiform ablation scars.

Long-term success of RF ablation is therefore not guaranteed and depends on a number of factors, so that in many cases re-treatment is required to treat cardiac arrhythmia.

Another problem with RF ablation is the generation of transmural scars. It can happen that a scar does not pass through the entire heart muscle and thus is not transmural. Also, the treatment success can be reduced.

In clinical ablation catheters, a high-frequency current is regularly injected into the heart tissue. This creates locally so much heat that it comes to a destruction of tissue that is in contact with the ablation catheter. Due to the thermal conductivity of the tissue, even deeper tissue is destroyed whose temperature rises above a certain threshold. This tissue may be in the vicinity of the catheter, but need not necessarily be in direct contact with the ablation catheter. In particular, arrhythmogenic tissue is destroyed here.

The problem may arise that no defined and / or reproducible scars occur because the energy distribution in the tissue can be uneven. The energy distribution in the tissue can depend on several factors, eg. As the nature of the contact surface, a contact pressure, a blood flow, etc. The energy distribution is therefore not previously unambiguously assessable. However, uneven and / or non-transmural scars can significantly reduce long-term treatment success because tissue that has been inadequately heated can revitalize after a few days.

The invention has for its object to improve the treatment of cardiac arrhythmia, in particular to improve the reproducibility of scarring on tissue.

This object is solved by the subject matters of the independent claims. Preferred embodiments are the subject matters of the dependent claims.

One aspect relates to an ablation catheter having a catheter head, at the distal end of which a plurality of electrodes are arranged. In this case, each of the electrodes can be individually controlled to measure an electrical signal and / or to ablate tissue. Alternatively or additionally, the catheter head is at least partially formed of an elastic polymer.

The catheter head may be formed as a distal end element of the ablation catheter, that is, as that element of the ablation catheter that is to be brought into direct contact with the tissue to be treated by the ablation. This may be the dimensions of a typical clinical catheter head, so z. B. about a substantially cylindrical catheter head with a cylinder diameter of about 2 mm to about 3 mm and a cylinder height of about 4 mm to about 8 mm. The distal end of the catheter head may be formed as an end surface of the catheter head, in particular as a cylinder end. The distal end may be formed substantially flat and be provided to be placed substantially flat on the tissue to be treated and / or placed in touching contact.

At the distal end of the catheter head, the plurality of electrodes is arranged. The electrodes may in particular be arranged in a substantially uniformly arranged pattern on the catheter head, in particular in an array. The catheter head can thus have a multi-electrode array.

Each of the electrodes is formed of an electrically conductive material and intended to be brought into direct contact contact with the tissue to be treated. In this case, both a physical contact and an electrical contact with the tissue to be treated getting produced. The individual electrodes can be arranged isolated from one another on the catheter head so as to prevent an averaging of the individual signals at the electrodes, as a result of which spatial information can be lost. Each of the electrodes may be formed as a measuring electrode and serve to measure an electrical signal, in particular an electrical current and / or an electrical voltage, and / or be designed as Ablationselektrode for applying tissue with an ablation. This z. For example, some electrodes may be formed as measuring electrodes, some electrodes as ablation electrodes and some electrodes both as measuring electrodes and as ablation electrodes. Preferably, each of the electrodes is designed both as a measuring electrode and as an ablation electrode.

By using a plurality of measuring electrodes, it is possible to achieve a spatial resolution on the tissue to be treated by the ablation. In particular, the impedance at the position of the respective electrode can also be measured as an electrical signal. The impedance measured at each of the electrodes depends on the environment of the electrode. In particular, it can be read on the basis of the measured impedance, whether the electrode makes contact with scarred or unhardened tissue, or whether the electrode is not in touching contact with tissue. Depending on this measurement, the ablation energy for the respective electrode can be determined. The ablation energy can be applied to the electrodes in the form of high-frequency alternating current.

When carrying out the ablation, the electrical signals at the electrodes can be alternately measured, then an ablation can be performed, then again the new electrical signals are measured and, depending on the measurement result, an ablation is carried out again. The measurement of the electrical signals and the ablation can thus be iterated until the desired result, ie z. B. has set a predetermined Vernarbungsgeometrie.

By using the same electrodes for both measurement and ablation, the components of the ablation catheter are used particularly efficiently. In addition, the ablation energy can be performed exactly at the positions of the tissue on which the electrical signals have also been measured.

The described ablation catheter thus makes it possible to generate an ablation scar in the tissue exactly as desired by the physician performing the treatment. In particular, the ablation may be performed so that the electrical signals measured at the individual electrodes suggest that the scar is transmural at the desired locations.

The catheter head is at least partially formed of an elastic polymer. This type of training makes it possible that the polymer head is not rigid, but that in particular and / or at least the distal end of the catheter head is designed to be flexible and / or pivotable. Catheters are usually passed through the body of the patient over a distance of several centimeters and / or several decimetres to the tissue, e.g. As heart tissue, out, which should be treated. If the catheter head is routed through the patient's body to the target tissue, it may be due to the individual body geometries that the distal end can not be laid flat on the target tissue. This is even the case regularly, so that the catheter head obliquely impinges on the tissue to be treated. This skewing may cause the electrodes to be in varying degrees of contact contact and / or electrical contact with the tissue to be treated, or in extreme cases, even to cause individual electrodes to be out of contact with the treating tissue. The formation of the catheter head of the elastic polymer makes it possible for the catheter head to "cling" to the tissue to be treated. In this case, the distal end can be tilted in contact contact with the target tissue, in particular with respect to a rest position. The coefficient of elasticity of the polymer is in this case designed so that the distal end of the catheter head can be bent with a pressure on tissue, which is so low that the pressure does not damage the tissue.

The use of the elastic polymer thus improves the contact between the distal end of the catheter head and the tissue to be treated. The polymer used may furthermore be designed to be electrically insulating. This improves the influence of the measurement of the electrical signals and the application of the ablation energy to the individual electrodes. In particular, the catheter head may also be formed essentially completely from the elastic polymer. This improves the ability of the catheter head to conform to the tissue to be treated.

The catheter head can in this case be formed in an insertion direction of the ablation catheter at least in sections over its entire cross section (minus the electrodes or their electrical leads) from the elastic polymer. In other words, the catheter head is at least partially substantially completely formed from the polymer. This allows a Deformation of the distal end of the catheter head in every possible spatial direction. This allows a high adaptability of the catheter head.

Here are basically deformations of the catheter head in all directions possible. In particular, the elasticity of the catheter head allows the catheter head to be pressed in and bent, while shearing and torsional deformations are undesirable and possibly inhibited.

Overall, there are the types of deformation: tension, compression, bending, shear and torsion. Train will hardly take place in use as an ablation catheter. Compression deformations are desirable and advantageous. Bending in the longitudinal axis of the catheter head is planned and advantageous, other bends are unlikely due to the cylindrical shape. Shearing in planes along the cylinder axis may also be permitted, which may be superimposed with the longitudinal bend of the catheter head. Although shear in planes transverse to the cylinder occur, but are not intended and are only tolerated. Small torsions about the longitudinal axis are likely and tolerable, but can be kept as small as possible. An occurrence of other torsions is unlikely.

In one embodiment, the resilient polymer is resiliently configured to allow for tilting of the distal end of the catheter head by at least about 10 degrees relative to a resting position of the catheter head. In other words, the catheter head can be at least partially tilted by at least about 10 °, preferably at least about 15 °, more preferably at least about 20 ° relative to its rest position. Possibly. In the catheter head existing electrical lines for the electrodes can in this case also bend so that they join the deformation of the catheter head. In this case, the electrical leads and / or the electrodes may be formed of a soft metallic conductor and / or so thin that they can easily follow the deformation of the catheter head. This allows an adaptability of the catheter head by said angle to the tissue to be treated. The fact that the catheter head adapts with its shape to the tissue to be treated, the catheter does not need to be pressed as strong on the tissue, as is the case with conventional catheters. In order to bring conventional catheters into contact with the tissue with a rigid catheter head in such a way that all measuring electrodes are in contact with the tissue, they are often simply pushed deeper and more firmly onto the tissue. This may result in irregular and uncontrolled scars in the tissue to be treated. However, in the tiltable catheter head according to the invention, the electrodes can all be brought into contact with the tissue to be treated substantially uniformly, which improves the quality of the scar.

In one embodiment, the polymer is formed as an elastomer. In this case, the elastic polymer may have a modulus of elasticity of at most about 1000 kPa, preferably of at most about 500 kPa, preferably of at most about 100 kPa. Since muscle tissue usually has a similar high elasticity, z. B. from about 10 kPa to about 100 kPa, so that the elasticity of the polymer used is similarly strong or slightly stronger than the elasticity of the tissue to be treated. This allows a particularly good adaptability of the distal end of the catheter head to the tissue to be treated. In particular, the polymer used may be formed ultraelastisch, so have a modulus of elasticity of about 1 kPa. For example, as a sufficiently suitable and sufficiently elastic polymer, a PDMS polymer can be used, which stands for polydimethylsiloxane polymer as an abbreviation.

In general, the polymer may be formed as an elastomer.

In one embodiment, the elastic polymer is formed as a biocompatible and / or bioinert polymer. This means that the polymer is suitable and / or licensed to be introduced into the human body. This is z. A PDMS polymer.

According to one embodiment, the ablation catheter has a control for individually driving the electrodes in response to an electrical signal measured at the electrodes. Here, each electrode may be connected via an electrical supply line such as a wire to the controller. Both the individual electrodes and the electrical supply lines can be electrically insulated from one another in order to prevent and / or reduce a signal overlay.

The controller is designed and intended to detect the electrical signals measured by the individual electrodes, and to determine, in dependence on the detected electrical signals, an individually determined electrical ablation energy for each electrode and, for. B. to a corresponding execution command, to create the respective electrode.

The controller may include a processor and / or programmed instructions. The controller may in particular be designed as a computer program product and / or software product running on a computer.

The use of a plurality of electrodes makes it possible to achieve spatial resolution on the tissue to be treated by the ablation. As described, in particular, the impedance at the position of the respective electrode can be measured as the electrical signal. The impedance measured at each of the electrodes depends on the environment of the electrode. In particular, it can be read on the basis of the measured impedance, whether the electrode makes contact with scarred or unhardened tissue, or whether the electrode is not in touching contact with tissue. Depending on this measurement, the controller may set the ablation energy for the particular electrode. Thus, a higher value can be determined as ablation energy for an unhardened tissue than for a complete and / or partially scarred tissue.

When carrying out the ablation, the electrical signals at the electrodes can be alternately measured, then an ablation can be performed, then again the new electrical signals are measured and, depending on the measurement result, an ablation is carried out again. The controller can thus be designed, in particular, to iterate the measurement of the electrical signals and the ablation until the desired result has been established.

The control thus makes it possible to produce an ablation scar in the tissue exactly as desired by the physician performing the treatment. In particular, the ablation may be performed so that the electrical signals measured at the individual electrodes suggest that the scar is transmural at the desired locations.

According to one embodiment, the controller is adapted to apply to each of the electrodes an ablation energy in dependence on the strength of the electrical signal measured at the respective electrode. This z. B. value ranges of the measured electrical signal are determined, in which a certain Ablationsenergie is provided for each electrode. If the measurement results in z. For example, if a particular electrode is in touching contact with fully scarred tissue, the ablation energy for that electrode may be set to zero. If the measured electrical signal indicates that one of the electrodes is in touching contact with a partially scarred tissue, a lower ablation energy may be provided for that electrode than for another of the electrodes where the measured electrical signal indicates that this electrode is in contact with the electrode Contact with uncured tissue is. Thus, measurements may be taken alternately by the controller and ablations, for example all of the electrodes, may be in touching contact with sufficiently scarred tissue. In this case, the controller can in particular apply an ablation energy to each of the electrodes, which is higher, the stronger the electrical signal measured at the respective electrode. The strength of the measured electrical signal may in particular be related to the fact that the tissue contacting the respective electrode is electrically active and thus to be scarred by ablation. Scarred tissue is usually less electrically active than unhardened. The control can thus take place in direct correlation between the strength of the measured electrical signal and the intensity of the ablation energy.

According to one embodiment of one of the ablation catheters mentioned above, the electrodes protrude from the catheter head at the distal end of the catheter head substantially parallel to one another. In this embodiment, therefore, the electrodes are not inclined with respect to the insertion direction of the ablation catheter, but rather are formed essentially parallel to the insertion direction of the ablation catheter. By using substantially straight electrodes, the required space is minimized, particularly with regard to obliquely emerging from the distal end electrodes of conventional ablation catheters. By using substantially straight electrodes, the electrical signals measured at the individual electrodes can be compared particularly well with each other, the electrodes being all the same. As a result, the electrodes thus formed are particularly suitable as measuring electrodes for the detection and spatial resolution of the tissue to be treated.

According to one embodiment, the plurality of electrodes comprises at least one central electrode arranged centrally on the catheter head as well as a plurality of outer electrodes which are arranged in an array around the at least one central electrode. In this case, for example, the central electrode may be slightly wider than the outer electrodes. In particular, an electrical voltage between the central electrode and each of the outer electrodes can be measured as an electrical signal for controlling the individual electrodes. The outer electrodes may be arranged substantially uniformly spaced around the central electrode, e.g. B. in a regular arrangement.

In one embodiment, at least some of the electrodes have a diameter of at most 0.2 mm at least at their respective distal end. In other words, the electrodes are made comparatively small. For example, you can at least all outer electrodes have such a small diameter. The same can also apply to the dimensioning of the possibly present central electrode. Thus, in particular all of the electrodes can also have a diameter of at most 0.2 mm at their respective distal end. The distal end of the respective electrodes in this case is the end of the electrodes, which is designed and intended to be brought into direct contact with the tissue to be treated and to be arranged facing this tissue during the treatment. At this end, the electrodes z. B. have a diameter of about 0.05 mm to about 0.2 mm. With this size, the electrodes are particularly well suited to selectively measure a specific point of the tissue to be treated and selectively apply the ablation energy to the desired target site. The use of such small electrodes improves both the resolution in measuring the tissue to be treated and the accuracy of applying ablation energy to the tissue to be treated.

In one embodiment, at least some of the electrodes are formed as external electrodes disposed in at least one circle about a center of the distal end of the catheter head, e.g. B. to a central electrode. The outer electrodes may also be arranged in two or more circles around the possibly present central electrode. In this case, precisely the circular piece of tissue can be measured and / or treated with the ablation catheter, which is defined by the position of the outer electrodes arranged in the at least one circle. The most regular possible arrangement of the outer electrodes, ie the arrangement in at least one circle, improves the comparability of the electrical signals measured at the individual electrodes and thus the accuracy and the repeatability of the treatment.

In a further development, the ablation catheter has at least six outer electrodes, which are, for example, hexahedral around a center of the distal end of the catheter head, for. B. around a central electrode, are arranged around. In particular, the catheter head may also have eight outer electrodes, which are arranged around the center substantially in a circle. The use of at least six external electrodes, in particular the use of at least eight external electrodes, increases the resolution so strongly that particularly good measurements of the tissue to be treated and also particularly targeted application of ablation energy can take place.

In one embodiment, the catheter head includes at least one spacer integrally formed with the elastic polymer catheter head at the distal end of the catheter head. The spacer may, for. B. protrude a few tenths of a millimeter from the catheter head for establishing a distance between the distal end of the catheter head and the tissue. The spacer can thus be formed in particular from the same elastic polymer as the catheter head. In this case, the catheter head can also have a plurality of spacers, which for example protrude radially outward around the plurality of electrodes from the distal end of the catheter head. In this case, the spacers may have a larger diameter than the electrodes. As a result, the catheter head is adapted with its distal end more gently to the tissue to be treated than with its compared to the spacers small and therefore relatively pointed electrodes that could otherwise injure the tissue. This reduces the risk of injury and improves fitting of the distal end of the catheter head to the surface of the tissue to be treated.

The spacers may also allow for blood flow directly to the central ablation electrodes located in the middle of the ablation catheter and, thus, cooling of the tissue beneath these electrodes. Thus it can be unloaded longer and be entered by conduction, the heat in deeper tissue. Tissue, which sits directly on the ablation electrodes, is cooled by the blood, thus reducing the risk of carbonation.

• – ein Katheterkopf an dem Gewebe angeordnet wird, wobei am distalen Ende des Katheterkopfes eine Mehrzahl von Elektroden angeordnet ist, und wobei jede der Elektroden individuell ansteuerbar ist zur Messung eines elektrischen Signals und/oder zur Ablation von Gewebe, und
• – der Katheterkopf, welcher zumindest teilweise aus einem elastischen Polymer ausgebildet ist, unter Verformung des Katheterkopfes auf das Gewebe aufgebracht wird.

One aspect relates to a method of performing ablation in a tissue, wherein

• A catheter head is arranged on the tissue, a plurality of electrodes being arranged at the distal end of the catheter head, and each of the electrodes being individually controllable for measuring an electrical signal and / or for ablating tissue, and
• - The catheter head, which is at least partially formed of an elastic polymer, is applied to the tissue under deformation of the catheter head.

The method can be carried out in particular with an ablation catheter according to the aspect described above. Therefore, all statements made in connection with the ablation catheters also apply to the procedure and vice versa. In the method, for. B. each of the electrodes are individually controlled in response to an electrical signal measured at the electrodes.

One aspect relates to the use of an ablation catheter according to any preceding aspect for performing ablation on tissue.

The invention will be described in more detail with reference to exemplary embodiments shown in FIGS. Individual features shown in the figures can be combined with other embodiments to form further embodiments. Like reference numerals denote the same or similar features of the embodiments shown. Show it:

1 in a schematic representation of a view of a distal end of a first catheter head;

2 a schematic view of a distal end of a second catheter head;

3 a schematic representation of a diagram for different distributions of ablation performance at the distal end of a catheter head;

4A in a technical representation of a plan view of an ablation catheter with a third catheter head;

4B in a technical representation, a side view of the ablation catheter with the third catheter head;

4C in a technical representation, a view of a distal end of the third catheter head;

4D in a technical representation, a side view of the distal end of the third catheter head;

4E in a technical representation an enlarged view of the distal end of the third catheter head:

5A in a perspective view of a catheter head with a central electrode in the rest position;

5B in a front view of the catheter head with a central electrode;

5C in a side view of the catheter head with a central electrode in the rest position;

5D in a side view of the catheter head with a central electrode in a working position;

6A in a perspective view of a catheter head without central electrode;

6B in a front view of the catheter head without central electrode;

6C in a side view of the catheter head without central electrode in rest position;

7A in a perspective view of a catheter head with spacers;

7B in a front view of the catheter head with spacers; and

7C in a side view of the catheter head with spacers in rest position.

1 shows a schematic representation of a view of a distal end 110 a first catheter head 100 , The perspective is in 1 chosen so that a viewer's head on the distal end 110 looks, for example against the z-direction of the in 1 shown coordinate system. The distal end 110 is formed substantially flat and extends along a plane which is arranged in the displayed coordinate system in the x and y direction. The first catheter head 100 is formed as part of an ablation catheter and configured with the distal end 110 advance to be applied to tissue to be treated. After a substantially flat arrangement of the distal end 110 Ablation can be performed on the tissue to be treated.

The catheter head 100 may be formed as a heart catheter head and have a diameter of about 2.7 mm, which is shown in FIG 1 is indicated schematically. Even if the catheter head 100 is shown with a substantially square cross-section, the catheter may also have a substantially circular or oval cross-section. At the distal end 110 is a plurality of electrodes 120 and 130 arranged. Essentially centrally in the middle of the flat distal end 110 is a central electrode 120 arranged. Around this central electrode 120 around are several external electrodes 130 arranged along a ring R. In the exemplary embodiment shown, the first catheter head 100 exactly one central electrode and exactly six outer electrodes 130 on. In this embodiment, the catheter head 100 thus seven electrodes.

The six external electrodes 130 are substantially equally spaced apart and form a hexahedron around the central electrode 120 around.

In the embodiment shown, the ring R has a diameter of 1.50 mm. Furthermore, all electrodes have 120 and 130 a diameter of 0.50 mm. With this dimensioning can all electrodes 120 . 130 comfortable and efficient at the distal end 110 to be ordered.

In the embodiment shown, all electrodes 120 . 130 both serve to measure an electrical signal at the electrodes and to apply an ablation energy. Alternatively, the outer electrodes 130 also be designed only as measuring electrodes and only the central electrode 120 as ablation electrode. In this case, the central electrode 120 z. B. have a larger diameter than the outer electrodes 130 , In general, either only the outer electrodes 130 or all electrodes 120 . 130 be designed as measuring electrodes for measuring an electrical signal. Furthermore, either only the central electrode 120 or all electrodes 120 . 130 formed as Ablationselektrode for applying tissue with an ablation energy. Preferred is each electrode 120 . 130 formed both as a measuring electrode and as an ablation electrode.

2 shows a schematic representation of a view of a distal end 210 a second catheter head 200 , The perspective of the view is like in 1 shown. The second catheter head 200 indicates at its distal end 210 also a plurality of electrodes 220 . 231 and 232 on. Essentially in the middle of the flat distal end 210 is a central electrode 220 arranged. In a first ring R1 around the central electrode 220 around are several first, inner outer electrodes 231 arranged. In a second ring R2 around the central electrode 220 around, whose ring diameter is larger than the ring diameter of the first ring R1, are also a plurality of second outer outer electrodes 232 arranged.

In the exemplary embodiment shown, six first outer electrodes are along the first, inner ring R1 231 arranged and along the second, outer ring R2 also six second outer electrodes 232 , Here are both the first outer electrodes 231 along the first ring R1 as well as the second outer electrodes 232 along the second ring R2 substantially uniformly spaced apart along the respective ring R1 and R2, respectively. Furthermore, the second external electrodes 232 each "gap" to the first outer electrodes 231 arranged, that is from the central electrode 220 from between two first outer electrodes 231 , This results in a particularly space-saving and efficient arrangement of the outer electrodes 231 and 232 ,

The first ring R1 has a diameter of about 1.25 mm. The second ring R2 has a diameter of about 2.1 mm. Each of the electrodes 220 . 231 and 232 has a diameter of 0.50 mm. Thus, an arrangement is provided in which a central electrode 220 and a total of 12 external electrodes 231 and 232 on the distal end 210 of the second catheter head 200 can be arranged with a diameter of about 2.7 mm. The in 2 shown second catheter head 200 represents an extension of the in 1 shown first catheter head 100 in which the resolution is increased when recording a multi-channel electrogram.

That in the two 1 and 2 shown electrode array is expandable to other electrodes, the z. B. in turn hexagonal around the electrode circuits shown in the rings R or R1 and R2 can be arranged. The in the 1 and 2 shown electrode diameter as well as the distances between the electrodes shown may vary. The electrodes in adjacent rings can each be arranged at a gap to the electrodes in the respectively adjacent rings in order to reduce possible interactions and to increase the spatial distribution (and thus the resolution).

Each of the catheters may also include a purge, not shown, and / or a temperature sensor.

At each of the electrodes 120 . 130 . 220 . 231 and 232 An ablation power to be applied can be set separately and individually. As a result, different performance profiles can be set, which can be varied depending on the desired scar formation.

3 shows a schematic representation of a diagram for two different distributions of ablation performance at the distal end of a catheter head. Shown in the diagram is the power P in watts along the x-direction. Schematically represented in the diagram are two different power distributions. The arrows shown mark the electrode positions. The power distribution is adjustable depending on the power applied individually to the individual electrodes. A first power distribution has a minimum centrally in the middle of the distal end and a maximum at the edges of the distal end, while a second power distribution shown has a maximum in the center of the distal end and a minimum at the edges. The x-direction over which the power distribution is plotted is, for example, in 1 and extends across the surface of the distal end 110 respectively. 210 ,

The performance profiles can be varied according to the desired scar formation.

4A shows a technical view of a plan view of an ablation catheter 1 with a third catheter head 300 ,

The in the 4A to 4E shown ablation catheter 1 is z. B. is not intended for clinical use due to its size. The third catheter head 300 However, it is an embodiment of a realization possibility in the clinical environment. The in the 4A to 4E shown ablation catheter 1 represents an implementation possibility for an experimental setup.

In general, ablation catheters are substantially elongated, in particular as elongate cylinders, so as to be guided along an artery or vein to the tissue to be treated, for example. In the embodiment shown, the ablation catheter 1 87.25 mm long including electrical leads protruding from the catheter at the end 350 , The electrical wires 350 connect each of the electrodes of the ablation catheter 1 with a controller, not shown. The electrical wires 350 run from the third catheter head 300 up to the controller, not shown.

4B shows a side view of the ablation catheter 1 , Here is in 4B shown that the electrical wires 350 unilaterally along one side of the ablation catheter 1 are arranged. An opposite side and in particular a center of the ablation catheter are formed line-free, z. B. for other technical elements of the ablation catheter 1 (such as a purge, a tube, a camera connection and / or the like) or for blood flowing through the veins and / or arteries.

The ablation catheter 1 is elongate and extends along an insertion direction E, which in the 4A and 4B indicated by an arrow. The insertion direction E extends from a proximal end of the catheter 10 along a catheter body 20 of the ablation catheter 1 up to the catheter head 300 essentially straightforward. The catheter body 20 can be designed as a flexible hose, in which the electrical lines 350 are arranged. When inserting the ablation catheter 1 can the catheter body 20 adapt to his transfer path, so z. As the shape of the arteries and / or veins through which he is relocated.

The catheter head 300 is at the distal end of the ablation catheter 1 arranged. Further details of the third catheter head 300 of the ablation catheter 1 are in the following 4C . 4D and 4E shown.

4C shows a technical view of a view of the distal end 310 of the third catheter head 300 , The distal end 310 is substantially disc-shaped and formed substantially flat. At the center of the disc is a central electrode 320 arranged. Circular around this central electrode 320 are several external electrodes 330 arranged. In the embodiment shown, the catheter head 300 a single central electrode 320 and eight annular around the central electrode 320 arranged outer electrodes 330 on. Outside this ring of external electrodes 330 are several spacers 340 at the distal end 310 arranged. The spacers 340 are in an outer ring around the inner ring of the outer electrodes 330 trained around.

In the embodiment shown, the distal end 310 six spacers 340 on. In other embodiments, the distal end may have more or fewer spacers 340 exhibit.

4D shows a side view of the catheter head 300 , Also shown in 4D is the insertion direction E. The insertion direction E is in this case substantially parallel to the cylinder axis of the substantially cylindrical catheter head 300 , The distal end 310 of the catheter head 300 corresponds to the circular area of the catheter head 300 holding the catheter head 300 closes in the insertion direction E. All external electrodes 330 protrude substantially parallel to the insertion direction E from the distal end 310 out. Thus, the outer electrodes 330 essentially all arranged parallel to each other. The outer electrodes 330 can be parallel to the central electrode 320 from the distal end 310 protrude. This can also be the central electrode 320 substantially parallel to the insertion direction E aligned from the distal end 310 protrude. Just like the outer electrodes 330 also protrude the spacers 340 from the catheter head 300 out, and substantially parallel to each other and substantially parallel to the insertion direction E. The insertion direction E is substantially perpendicular to the surface, which is the distal end 310 forms. The insertion direction E can essentially be a solder on the distal end 310 in the resting position of the catheter head 300 form.

The catheter head 300 is at least partially formed of an elastic polymer. In particular, the catheter head 300 at least in sections in the insertion direction E substantially completely formed of an elastic polymer. Like the catheter head 300 can also use the spacers 340 be formed of the same elastic polymer. This shows at least the catheter head 300 an elasticity, which is a deformation of the catheter head 300 allows. The elastic polymer may be non-conductive and the individual electrodes 320 and 330 electrically isolate against each other. The polymer also isolates those through the catheter head 300 laid electrical lines 350 up to today. Due to the elasticity of the catheter head 300 will be an adaptation of the catheter head 300 allows for the topography of the heart tissue, and thereby a stable and / or uniform contact with the tissue to be treated. In the 1 to 4 the treating tissue is not explicitly shown.

The electrical wires 350 are each with each one of the electrodes 320 and 330 electrically connected. For this purpose, each of the electrodes is via a first line section 351 contacted directly from the distal end 310 protruding part of the electrode inside the catheter head 300 is arranged running. Here, each of the first line sections 351 arranged substantially parallel to the insertion direction E. Subsequently, the electrical line runs 350 over a substantially parallel to the distal end 310 arranged second line section 352 to an edge of the ablation catheter 1 on which the electrical wires 350 are arranged. The second line sections 352 are designed and arranged, the electrical connections all to the same side of the ablation catheter 1 relocate. At this one common site, the in 4D is shown on the right, for each electrode in each case a third line section 353 Arranged by the catheter head 300 away to the proximal end 10 of the ablation catheter 1 runs (see for example 4A and 4B ). By this one-sided arrangement of the electrical lines 350 becomes a free space within the ablation catheter 1 provided.

4E shows a technical view of an enlarged view of the distal end 310 of the third catheter head 300 , The central electrode 320 may in this case have a larger diameter than the outer electrodes 330 , In the exemplary embodiment shown, the outer electrodes have a diameter of approximately 0.2 mm. All eight outer electrodes 330 are substantially evenly spaced from each other and disposed on a (first inner) ring R, which is central to the central electrode 320 around and at the distal end 310 of the third catheter head 300 is arranged. The six spacers 340 are arranged along a second outer ring, the center also with the position of the central electrode 320 coincides. The spacers 340 can have a diameter of about 0.5 mm. The embodiment shown has a catheter head 300 on, which has a diameter of about 7 mm. This is slightly larger than usual ablation catheters. Therefore, the dimensions shown of the embodiment shown are merely exemplary in that real catheter heads of an ablation catheter preferably have a smaller diameter of up to a maximum of 3 mm.

In 4E is also shown in dashed lines, as the electrical lines 350 inside the catheter head 300 from the outer electrodes 330 away together to one side of the ablation catheter 1 are laid.

The eight external electrodes allow a local measurement of the electrophysiological signals in the border area of the ablation scar. As a result, a reliable assessment of the grain geometry is possible.

By a separate energy coupling into the electrodes 320 and 330 Can regional scar growth on each of the electrodes 320 and 330 to be controlled. Due to large energy losses, the outer electrodes can 330 be subjected to a higher ablation energy than the central electrode 320 ,

It can thus be provided a control that already at the beginning of the ablation the outer electrodes 330 supplies a higher energy output than the central electrode 320 ,

5A shows in a perspective view a fourth catheter head 400 , at its distal end 410 centrally a central electrode 420 is arranged. Around the central electrode 420 around are eight external electrodes 430 arranged in a ring whose center is the central electrode 420 forms.

The catheter head 400 is formed in two parts and has a first head part 401 and a second header 402 on. At least the first headboard 401 , at the distal end 410 is substantially completely formed of an elastic polymer.

The second headboard 402 can either also be formed of the elastic polymer or of a rigid building material. Integrated in this second headboard 402 can the electrodes 420 and 430 be arranged. In addition, at this second headboard 402 be arranged further measuring electrodes.

The first headboard 401 is (except for the electrical wires for the electrodes 420 . 430 ) substantially completely and / or solidly formed from the elastic polymer, from an interface between the first head part 401 and the second headboard 402 to the distal end 410 of the catheter head 400 ,

As a result, at least the first head part 401 of the catheter head 400 elastic and thus deformable. The first headboard 401 is the same as the second headboard 402 formed substantially cylindrical, wherein the cylinder circumference of the first head part 401 the cylinder circumference of the catheter head 400 equivalent. In addition, also the cylinder circumference of the second head part 402 the cylinder circumference of the catheter head 400 correspond.

5B shows in a frontal view the distal end 410 of the catheter head 400 opposite to the insertion direction E. To the single central electrode 420 are the eight outer electrodes 430 arranged in a ring. The outer electrodes 430 are formed substantially uniformly spaced from each other along the ring.

5C shows in a side view the first head part 401 of the catheter head 400 in a resting position. At rest, the distal end closes 410 of the catheter head 400 the first headboard 401 essentially at right angles, ie that the surface of the distal end 410 is arranged substantially perpendicular to the lateral catheter head walls, the catheter head 400 as cylinder walls limit.

5D shows in a side view the first head part 401 of the catheter head 400 the one in a working position. In the working position is the distal end 410 flat on a fabric 50 placed. The tissue 50 can z. B. be formed as a heart tissue of a patient.

The surface of the tissue is inclined at an angle to the surface, that of the distal end 410 is formed in its rest position. The first headboard 401 of the catheter head 400 is hereby compressed on one side, so that the orientation and / or inclination of the distal end 410 Adjusts to the inclination of the tissue surface. During compression, the first catheter head can 400 bulging in places. In the working position is the distal end 410 of the catheter head 400 essentially parallel to the tissue surface of the tissue 50 arranged. The distal end 410 of the catheter head 400 is inclined to the rest position, namely by an inclination angle á.

The inclination of the distal end 410 is due to the formation of the first head part 401 made of the elastic polymer that allows the partial compression of the catheter head 400 allows.

If the surface of the tissue to be treated is not substantially parallel to the distal end 410 of the catheter head 400 is formed, the catheter head 400 for example, tipping and / or kinking and / or bending. This will be the distal end 410 from the into the 5A - 5C shown rest position deflected and / or deflected. In doing so, the surface of the distal end fits 410 to the surface of the tissue to be treated. As a result, targeted energy delivery of the electrodes to the tissue can take place during ablation. Furthermore, this results in a higher measuring reliability of the electrodes. Each one of the outer electrodes 430 and optionally also the central electrode 420 (see. 5A to 5C ) can be used as a measuring electrode, for example, the impedance of the tissue 50 to measure on which the respective electrode 430 respectively. 420 is attached.

Targeted energy delivery reduces variance in scar geometry during ablation, resulting in reproducible results.

The non-conductive catheter head 400 replaces conductive metal bodies of conventional ablation catheters. The use of the elastic polymer reduces a negative influence of a (conventionally used) metal body on the measurement signals. The insulating function of the polymer can thereby affect the electrodes 420 and 430 shield each other during both ablation and measurement. As a result, no further shielding is absolutely necessary, which reduces the production costs of the ablation catheter.

When casting the polymer for the catheter head 400 , in particular the first head part 401 , a high arrangement freedom is provided, in particular for the electrodes, which can be arranged either straight or even, for example, spirally.

6A shows in a perspective view a fifth catheter head 500 , at its distal end 510 centrally no central electrode is arranged, but rather only external electrodes 531 and 532 , Around a disk center of the distal end 510 around are six inner outer electrodes 531 and six outer outer electrodes 532 arranged in each case an inner ring or an outer ring.

The catheter head 500 is formed in two parts and has a first head part 501 and a second header 502 on. At least the first headboard 501 , at the distal end 510 ends, is formed of an elastic polymer.

The second headboard 502 may also be formed from the elastic polymer either or from a stiff building material. Integrated in this second headboard 502 can the electrodes 531 and 532 be arranged. In addition, at this second headboard 502 be arranged further measuring electrodes.

The first headboard 501 is (except for the electrical wires for the electrodes 531 . 532 ) substantially completely and / or solidly formed from the elastic polymer, from an interface between the first head part 501 and the second header 502 to the distal end 510 of the catheter head 500 , As a result, at least the first head part 501 of the catheter head 500 elastic and thus deformable. The first headboard 501 is the same as the second headboard 502 formed substantially cylindrical, wherein the cylinder circumference of the first head part 501 the cylinder circumference of the catheter head 500 equivalent. In addition, also the cylinder circumference of the second head part 502 the cylinder circumference of the catheter head 500 correspond.

6B shows in a frontal view the distal end 510 of the catheter head 500 , Around a disk center point (without central electrode) are the six inner outer electrodes 531 arranged along an inner ring. To the inner outer electrodes 531 around are the six outer outer electrodes 532 arranged along an outer ring. The outer electrodes 531 and 532 are formed substantially uniformly spaced from each other along their respective ring.

6C shows in a side view the first head part 501 of the catheter head 500 in a resting position. At rest, the distal end closes 510 of the catheter head 500 the first headboard 501 essentially at right angles, ie that the surface of the distal end 510 is arranged substantially perpendicular to the lateral catheter head walls, the catheter head 500 as cylinder walls limit. All external electrodes 531 and 532 protrude approximately equidistant from the distal end 510 out.

At least the first headboard 501 made of elastic polymer is the distal end 510 of the fifth catheter head 500 as well as the distal end 410 of the fourth catheter head 400 deformable, which is not shown in a separate figure.

7A shows in a perspective view a sixth catheter head 600 , at its distal end 610 centrally a central electrode 620 is arranged. Around the central electrode 620 around are six external electrodes 630 and six spacers 640 arranged in a ring.

The catheter head 600 is formed in two parts and has a first head part 601 and a second header 602 on. At least the first headboard 601 , at the distal end 610 ends, is formed of an elastic polymer.

The second headboard 602 can either also be formed of the elastic polymer or of a rigid building material.

The first headboard 601 is (except for the electrical wires for the electrodes 620 . 630 ) substantially completely and / or solidly formed from the elastic polymer, from an interface between the first head part 601 and the second header 602 to the distal end 610 of the catheter head 600 , As a result, at least the first head part 601 of the catheter head 600 elastic and thus deformable. The first headboard 601 is the same as the second headboard 602 formed substantially cylindrical, wherein the cylinder circumference of the first head part 601 the cylinder circumference of the catheter head 600 equivalent. In addition, also the cylinder circumference of the second head part 602 the cylinder circumference of the catheter head 600 correspond.

7B shows in a frontal view the distal end 610 of the catheter head 600 , Around the central electrode 620 around are the six outer electrodes 630 arranged along a ring. Between every two of the six outer electrodes 630 is one of the six spacers 640 along the same ring around the central electrode 620 arranged around. The outer electrodes 630 and the spacers 640 are formed substantially uniformly spaced from each other along the ring.

7C shows in a side view the first head part 601 of the catheter head 600 in a resting position. At rest, the distal end closes 610 of the catheter head 600 the first headboard 601 essentially at right angles, ie that the surface of the distal end 610 is arranged substantially perpendicular to the lateral catheter head walls, the catheter head 600 as cylinder walls limit. The spacers 640 protrude slightly further from the distal end 610 out as the electrodes 620 . 630 ,

At least the first headboard 601 made of elastic polymer is the distal end 610 of the sixth catheter head 600 as well as the distal end 410 of the fourth catheter head 400 deformable, which is not shown in a separate figure.

The illustrated embodiments may include a controller for the respective electrodes. In one embodiment, the controller is the Electrodes are designed so that first, for example, an older or trained in a previous step Ablationsnarbe is measured, and then targeted only those areas are desolate, which were not successfully destroyed in the previous treatment. This does not require renewed extensive destruction of healthy tissue around, for example, an older scar. The outer electrodes and / or (if present) the central electrode can serve for receiving and / or measuring an electrogram before and after RF ablation. Here, the measured scar geometry can be assessed locally. In the case of a hitherto insufficient ablation result, it is possible to address a scarcely formed scar geometry completely and / or with a specifically adjusted power weight.

By means of a local, for example circular, measurement by means of the outer electrodes of the electrophysiological signals of the heart tissue around the central ablation point, electrical data for determining the surface geometry and / or the transmurality of the ablation scar can be provided. By means of the proposed arrangement of the electrodes and by means of the evaluation of the electrical data, complex scar geometries can also be described, for example in the case of overlapping two substantially punctiform ablation scars. Via the, for example, hexagonal electrode arrangement of the multi-electrode array, a high-frequency current can be fed into the tissue, whereby the RF ablation is performed. In this case, the high-frequency current in each individual electrode can be adjusted separately so that a targeted adjustment of the energy transfer into the tissue can take place. The individual embodiments may have electrodes with a different diameter and / or different distances from one another than shown in the embodiments.

Due to the high number of electrodes, detailed multichannel electrograms can be recorded, which provide a spatially well-resolved impression of the existing tissue structure and / or scar geometry.

Due to the elasticity of the polymer of the catheter head as flat as possible resting distal end of the catheter is possible, whereby oblique bearing angle of the catheter head and thus distorted scar geometries are reduced, especially in the edge region.

Instead of the individual central electrode shown in the exemplary embodiments, a plurality of electrodes can also be arranged in the center, that is to say a plurality of central electrodes, or no electrode at all (as, for example, in the case of the fifth catheter head 500 ).

The electrodes may be made of silver, for example. Those electrodes which are also used for an electrophysiological measurement may additionally be chlorinated. If the chlorination does not turn out evenly, this can also be repeated. Since the chlorination is not always the same for all electrodes, the recorded electrical signals can vary in terms of their amplitude morphology and / or sensitivity. Therefore, the individual electrodes can be adjusted prior to their use, so that each electrode has a predetermined measurement accuracy z. B. by means of a measurement correction value and / or a Ablationsenergieeinspeisungsgenauigkeit z. B. can be assigned by means of a Ablationsenergieeinspeisungskorrekturwerts. Corresponding measured values, accuracies and / or correction values can be pre-stored in the controller. Alternatively, gold and / or platinum can also be used as the electrode material, whereby chlorination is no longer required.

Instead of or in addition to lesion generation with radiofrequency ablation, a cryoablation can be used in which tissue is desquamated by means of strong hypothermia via the individual electrodes.

LIST OF REFERENCE NUMBERS

1

ablation catheter

10

proximal catheter end

20

catheter body

50

tissue

100

catheter head

110

distal end of the catheter head

120

central electrode

130

outer electrode

200

catheter head

210

distal end of the catheter head

220

central electrode

231

inner outer electrode

232

outer outer electrode

300

catheter head

310

distal end of the catheter head

320

central electrode

330

outer electrode

340

spacer

350

electrical line

351

first line section

352

second line section

353

third line section

400

catheter head

401

first head section

402

second head section

410

distal end of the catheter head

420

central electrode

430

outer electrode

500

catheter head

501

first head section

502

second head section

510

distal end of the catheter head

531

inner outer electrode

532

outer outer electrode

600

catheter head

601

first head section

602

second head section

610

distal end of the catheter head

620

central electrode

630

outer electrode

640

spacer

á

tilt angle

e

insertion

R

ring

R1

first ring

R2

second ring

Claims (13)

Ablation catheter ( 1 ) with a catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ), at its distal end ( 110 ; 210 ; 310 ; 410 ; 510 ; 610 ) a plurality of electrodes ( 120 . 120 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 531 . 532 ; 620 . 630 ), wherein - each of the electrodes ( 120 . 130 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 531 . 532 ; 620 . 630 ) is individually controllable for measuring an electrical signal and / or for the ablation of tissue and - the catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ) is at least partially formed of an elastic polymer. The ablation catheter of claim 1, wherein the elastic polymer is resilient to cause tilting of the distal end (US Pat. 110 ; 210 ; 310 ; 410 ; 510 ; 610 ) of the catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ) by at least about 10 ° relative to a resting position of the catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ). The ablation catheter of claim 1 or 2, wherein the polymer is formed as an elastomer. Ablation catheter according to one of the preceding claims, with a control for individually controlling the electrodes ( 120 . 130 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 531 . 532 ; 620 . 630 ) as a function of one at the electrodes ( 120 . 130 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 531 . 532 ; 620 . 630 ) measured electrical signal. The ablation catheter of claim 4, wherein the controller is adapted to apply to each of the electrodes (10). 120 . 130 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 531 . 532 ; 620 . 630 ) an ablation energy as a function of the strength of the at the respective electrode ( 120 . 130 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 531 . 532 ; 620 . 630 ) applied electrical signal. Ablation catheter according to one of the preceding claims, wherein the electrodes ( 120 . 130 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 531 . 532 ; 620 . 630 ) at the distal end ( 110 ; 210 ; 310 ) of the catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ) substantially parallel to each other from the catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 protrude). Ablation catheter according to one of the preceding claims, wherein the plurality of electrodes ( 120 . 130 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 620 . 630 ) at least one centrally on the catheter head ( 100 ; 200 ; 300 ; 400 ; 600 ) arranged central electrode ( 120 ; 220 ; 320 ; 420 ; 620 ) and a plurality of external electrodes ( 130 ; 231 . 232 ; 330 ; 430 ; 630 ) arranged in an array around the at least one central electrode ( 120 ; 220 ; 320 ; 420 ; 620 ) are arranged around. Ablation catheter according to one of the preceding claims, wherein at least some of the electrodes ( 120 . 130 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 531 . 532 ; 620 . 630 ) have a diameter of at most 0.2 mm at least at their respective distal end. Ablation catheter according to one of the preceding claims, wherein at least some of the electrodes are used as external electrodes ( 130 ; 231 . 232 ; 330 ; 430 ; 531 . 532 ; 630 ) formed in at least one circle about a center of the distal end ( 110 ; 210 ; 310 ; 410 ; 510 ; 610 ) are arranged around. Ablation catheter according to claim 9, with at least six external electrodes ( 130 ; 231 . 232 ; 330 ; 430 ; 531 . 532 ; 630 ). Ablation catheter according to one of the preceding claims, wherein the catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ) at least one spacer ( 340 ; 640 ) which is integral with the catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ) made of elastic polymer at the distal end ( 110 ; 210 ; 310 ; 410 ; 510 ; 610 ) of the Katherkopf ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ) is trained. Method for performing an ablation on tissue ( 50 ), wherein - a catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ) on the tissue ( 50 ) is arranged, wherein at the distal end ( 110 ; 210 ; 310 ; 410 ; 510 ; 610 ) of the catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ) a plurality of electrodes ( 120 . 130 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 531 . 532 ; 620 . 630 ), and wherein each of the electrodes ( 120 . 130 ; 220 . 231 . 232 ; 320 . 330 ; 420 . 430 ; 531 . 532 ; 620 . 630 ) is individually controllable for measuring an electrical signal and / or for ablation of tissue ( 50 ) and - the catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ), which is at least partially made of an elastic polymer, with deformation of the catheter head ( 100 ; 200 ; 300 ; 400 ; 500 ; 600 ) on the tissue ( 50 ) is applied. Using an ablation catheter ( 1 ) according to any one of claims 1 to 11 for performing an ablation on a tissue ( 50 ).

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