Mapping and ablation system suitable for linear pulse field cardiac ablation

Abstract

The present disclosure relates to a catheter (C) for ablating tissue, comprising: at least two ablation electrodes (A1, A2) configured to apply electrical energy pulses to tissue; wherein the catheter is configured such that, in an ablation position of the catheter, the ablation electrodes (A1, A2) contact the tissue along a main axis (z) of the catheter.

Description

Technical Field

[0001] The present invention generally relates to catheters, corresponding systems and methods for ablating tissue. Background Art

[0002] In the medical field, various methods and devices for ablating tissue are known. Typically, tissue ablation can be performed to treat and / or prevent various diseases. For example, it is known to ablate cardiac tissue to treat cardiovascular disease (e.g., arrhythmias such as atrial fibrillation, ventricular tachycardia, etc.). However, other types of tissue may also be ablated for medical purposes. In order to achieve reliable ablation therapy, it is generally necessary to control the tissue ablation process in a defined manner to ensure the patient's desired medical outcome. For example, it may be necessary to precisely control the spatial characteristics of the tissue to be ablated. To this end, it may be necessary to carefully control the process that causes the ablation, for example, to limit the ablation to a specific tissue type in the effective area of ​​the process.

[0003] A known method for tissue ablation is radiofrequency ablation (RFA), which is based on applying heat to tissue, wherein the heat is generated by an electric current in the radiofrequency range. This type of tissue ablation process can be performed by a single-tip catheter with point-by-point ablation of tissue (e.g., for cardiac tissue within a cardiac chamber). The region of ablated tissue can be formed by various ablation points (i.e., ablation sub-regions) ablated in the continuous ablation steps of the process, so that a total (continuous) ablation region can be formed. However, RFA treatment is not always optimal. The sequential nature of the process may generally require extended processing time. In addition, due to the sequential positioning of multiple ablation points in the point-by-point application of the process, the RFA process may result in high surgical complexity. Reliable positioning of the ablation points may not always be ensured, which may, for example, result in gaps of unablated tissue residing in the ablated tissue after surgery.

[0004] Another known method for tissue ablation is based on a cryogenic process. This may require a cryogenic linear catheter that can apply a cryogenic thermal budget to the tissue at its tip for local ablation thereof (e.g., by providing a cryogenic material). However, due to design constraints, the cryogenic linear catheter may be rigid, which may lead to (surgical) complications when performing tissue ablation. The cryogenic linear catheter may also not always be reliably positioned in the target area (e.g., they may slip out of the target area).

[0005] Therefore, currently known techniques do not always result in optimal ablation of tissue.Therefore, there is a need to find ways to improve tissue ablation. Summary of the invention

[0006] Aspects described herein at least partially address the above-mentioned needs.

[0007] A first aspect relates to a catheter for ablating tissue using pulsed field (PF) energy, the catheter being configured to be connected to a high voltage generator for generating PF energy, wherein the catheter comprises:

[0008] at least two ablation electrodes, in particular at least six ablation electrodes, configured to apply PF energy to the tissue,

[0009] wherein the catheter is configured such that, in an ablation position of the catheter, the ablation electrode contacts the tissue along a main axis of the catheter,

[0010] wherein the catheter comprises at least two separate electrical conductors for connecting the electrode to the high voltage pulse generator for generating PF energy,

[0011] wherein the at least two separated electrical conductors are adapted to deliver a waveform having a peak voltage of at least 1000 V, in particular at least 3000 V, to the electrodes, and wherein the ablation electrodes of the catheter may be spaced apart such that when they are excited by the waveform, the electric field within the cardiac tissue exceeds a strength of 400 V / cm at a depth of 5 mm.

[0012] A second aspect relates to a system for ablating tissue using pulsed field (PF) energy, the system comprising a catheter and a high voltage generator for generating PF energy, wherein the catheter comprises:

[0013] at least two ablation electrodes, in particular at least six ablation electrodes, configured to apply PF energy to the tissue,

[0014] wherein the catheter is configured such that, in an ablation position of the catheter, the ablation electrode contacts the tissue along a main axis (z) of the catheter,

[0015] wherein the generator is adapted to be connected to the electrode,

[0016] wherein the generator is adapted to deliver a waveform having a peak voltage of at least 1000 V, in particular at least 3000 V, to the electrode, and

[0017] Wherein, the ablation electrodes of the catheter may be spaced apart such that when they are excited by the waveform, the electric field within the cardiac tissue exceeds a strength of 400 V / cm at a depth of 5 mm.

[0018] A catheter for ablating tissue comprises at least two ablation electrodes, in particular at least six electrodes, which are configured to apply PF energy to the tissue. Pulsed field ablation (PFA) renders the target tissue nonviable by irreversible electroporation (IRE). The electric field generated by the applied PF energy creates holes in the membranes of target cardiac cells. If the PFA waveform and the characteristics of the catheter are appropriately selected, the holes opened in the cell membrane will last long enough for the cell to program itself to die. This process is called apoptosis. Reference "Modeling electroporation in a single cell. I. Effects of field strength and rest potential", DeBruin and Krassowska describe the process in more detail. The catheter can be configured so that at the ablation position of the catheter, the ablation electrode contacts the tissue along the main axis of the catheter. The distance between at least two, in particular at least six electrodes must be selected so that the field generated in the tissue exceeds a known IRE threshold (e.g. 400V / cm). The two ablation electrodes can be used as terminals of a circuit, wherein a defined voltage and / or current characteristic (e.g., in the form of a pulse) can be set between the two terminals. Thus, by establishing contact between the ablation electrodes and the tissue, voltage and / or current pulses between the electrodes can be delivered to the tissue. The electrode configuration of the present invention can allow PF energy to be applied to the tissue, which can cause a reaction in the tissue that results in ablation of the tissue, at least near the electrode and / or in an effective area (e.g., a continuous area) surrounding the electrode. Modulating the properties of the tissue can, for example, include creating local holes in the tissue and / or causing cell death within the tissue.

[0019] The ablation electrode can be positioned along the main axis of the catheter (e.g., at the outer surface of the catheter in a substantially linear manner, following the main axis, such as the longitudinal axis). Therefore, the alignment of the electrode relative to the tissue can be performed by controlling the main axis of the catheter without the need for a separate control mechanism and / or control component, which is the case if the electrode is arranged in a more complex position. Therefore, the catheter can be provided and used with lower complexity for contacting the ablation electrode with the tissue in the ablation position. Once the catheter is navigated to the desired position, it can simply be brought into contact with the surrounding tissue without having to perform additional positioning steps, because the ablation electrode can be automatically in the ablation position on the main axis without having to first finely position the electrode, for example, by extending additional positioning elements. In combination with the applied PF energy provided by the generator, ablation of the tissue can be performed along the catheter axis without the need to reposition the catheter. The ablation catheter using PFA of the present invention is intended to render the tissue nonviable by irreversible electroporation (IRE). During IRE, the electric field provided by the electrodes accommodated along the main axis of the catheter produces holes in the membranes of cardiac cells. When the number of holes and their size are large enough, IRE occurs and the cells themselves are programmed to die. Thus, a so-called ablation zone is formed along the ablation portion of the catheter (the distal portion of the catheter including the ablation electrode). This can shorten treatment time and reduce the requirements on the physician's skills and training.

[0020] The system and in particular the generator may be configured to deliver high voltage unipolar PF energy or bipolar PF energy or a combination of unipolar PF energy and bipolar PF energy, as described below. Figure 6 Some examples of applicable waveforms are shown in . Such waveforms, particularly in combination with the arrangement of electrodes, ensure that a single shot applies a sufficiently high electric field to produce a therapeutic effect capable of producing a conduction block groove. The generator may include an electronic control unit adapted to switch between monopolar PF energy and bipolar PF energy supply modes.

[0021] The aspects described herein can realize an ablation catheter whose ablation electrode can be easily and reliably positioned on the tissue by simply positioning the (side wall) surface of the catheter on the tissue, because the ablation electrode is positioned along the main axis of the catheter (at the ablation position). Therefore, the contact of the ablation electrode with the tissue and the ablation area can be controlled by (simply) controlling the main axis of the catheter. Therefore, the ablation position can be defined along the main axis of the catheter. Therefore, the ablation area of ​​the tissue can also be aligned along the main axis of the catheter. The catheter of the present invention can then remain stationary at the corresponding ablation position to apply PF energy to the tissue. Since the ablation area can extend (continuously) from the tissue contacted by the first ablation electrode of the at least two ablation electrodes to the tissue contacted by the second ablation electrode of the at least two ablation electrodes, a relatively large area can be ablated in a single shot without the risk of gaps and without having to move or reposition the catheter.

[0022] The main axis of the catheter can be curved (e.g., it may not always be aligned along a straight line). In this regard, the main axis can be flexible and can be oriented in various ways. The ablation electrode can be positioned in a portion of the catheter near the catheter tip. In an example, the main axis of the catheter in the portion near the catheter tip can be flexible and / or steerable to allow precise contact of the ablation electrode with the tissue. For example, it can be steerable so that it spans a two-dimensional plane (but it may not allow for a three-dimensional shape to be formed).

[0023] The ablation electrode can be formed as a ring electrode that can surround the periphery of the side wall of the catheter. The ablation electrode can also be formed as a tip electrode (e.g., covering the tip of the distal end of the catheter). In addition, the ablation electrode can be formed as a contact electrode that does not (necessarily) surround the periphery of the catheter (e.g., a sidewall electrode). However, any other type of electrode can be used as an ablation electrode. It is worth noting that the ablation electrode should be configured to be able to maintain the application of PF energy without damaging the ablation electrode. In this regard, the ablation electrode can include a stable current conducting material (e.g., gold, platinum, iridium or a combination thereof) that can reliably maintain a pulse. The material can also be adapted so that it does not significantly damage the biological properties of the tissue it contacts. The ablation electrode can be defined by a specific electrode area exposed on the outer surface of the catheter. When PF energy is applied, a portion of the electrode area or the entire electrode area can contact the tissue.

[0024] It is also conceivable that the ablation electrode does not necessarily come into direct contact with the tissue to be ablated, and may be located only in the vicinity of the tissue. However, even in this case, the application of an electrical energy pulse may be sufficient to induce electrical energy in the tissue to cause an ablation response thereof. In such indirect contact, the ablation electrode to tissue gap may be bridged, for example, by other materials (e.g., organic materials such as blood).

[0025] In an example, the ablation electrode may directly contact tissue in the ablation location that is not (significantly) ablated. In this example, the tissue may be an intermediate tissue, wherein the pulse is transmitted through the intermediate tissue to the tissue ablated in the ablation location. For example, the pulse may not exceed the ablation threshold of the intermediate tissue, but may exceed or reach the ablation threshold of the (adjacent) tissue so that it may be ablated.

[0026] The at least two ablation electrodes forming terminals for applying PF energy may, for example, include two different types of ablation electrodes (eg, a ring electrode and a tip electrode, a sidewall electrode and a tip electrode, and / or electrodes with different electrode areas, etc.).

[0027] In one example, the catheter can be configured so that tissue is ablated along a portion of the main axis in the ablation position, wherein the portion at least spans the distance between the ablation electrodes. Thus, the ablation region of the tissue can be shaped at least in part based on the distance between the ablation electrodes. In addition, the ablation region can be aligned along the main axis of the catheter because it will be oriented along a vector spanning between at least two ablation electrodes along the main axis. This is because pulses (e.g., voltage and / or current pulses) can be applied between the ablation electrodes so that the electrical energy is also substantially applied between the ablation electrodes. Therefore, the ablation reaction can be spatially limited to occur at least between the ablation electrodes along the main axis. It is worth noting that due to the corresponding lateral components of the pulses, there can also be a specific spatially limited lateral component of the reaction (which can be orthogonal to the main axis). This can generally ensure that the tissue is ablated along a portion of the main axis, and can be limited to the area where the ablation electrode is located on the main axis. Since the main axis in the ablation position corresponds to the main axis of the catheter, the present invention can achieve precise positioning of the ablation region.

[0028] It is noteworthy that the applied electrical energy pulses can also be based on the distance between the ablation electrodes to which the pulses are applied to ensure the desired results of the ablation. The ablation response of the tissue can depend not only on the pulse characteristics and / or the electrical energy of the pulses, but also on the electric field applied between the ablation electrodes generated by the pulses. Therefore, the applied pulses and / or their characteristics can be adapted to the distance between the ablation electrodes to ensure that an adequate ablation process of the tissue occurs.

[0029] In one example, the catheter can be configured so that in the ablation position, the elongated profile is ablated into the tissue. The elongated profile of the ablated tissue can be defined by a first end and a second end of the elongated shape. The first end and the second end can be the outermost points of the ablation area on opposite sides. The path between the first end and the second end can define the length of the elongated shape. The width can be defined in a direction orthogonal to the length, wherein the width can span the distance of the outermost points of the ablation area along the width direction. The elongated shape can be defined as the length of the elongated profile including at least twice the width of the elongated profile, preferably at least three times the width of the elongated profile, more preferably at least four times the width of the elongated profile, and most preferably at least five times the width of the elongated profile.

[0030] In the example of a catheter, at least one of the ablation electrodes may be positioned at a sidewall of the catheter such that it is distal from the tip of the catheter.

[0031] In one example, the ablation electrodes may be arranged in the distal portion of the catheter and distributed over a length of 3 to 6 cm, in particular 4 to 5 cm. This may result in an effective length of the ablation section of between 3 and 6 cm, in particular between 4 and 5 cm.

[0032] In the example of the catheter, the ablation electrode can be configured to apply an electric field to the tissue that is higher than and / or equal to a predetermined threshold, wherein the predetermined threshold is associated with the ablation threshold of the tissue. For example, the ablation threshold may include the minimum value of the electric field required to cause tissue ablation. Therefore, the predetermined threshold of the electric field to be applied may be at least the same as or higher than the ablation threshold. For example, the predetermined threshold may be selected to be higher than the ablation threshold to achieve a safety margin. This can ensure that the electric field during the application of the pulse will meet the ablation condition (i.e., an electric field higher than the ablation threshold), even if (unwanted) changes in the electric field occur. For example, different safety margins can be selected for the predetermined threshold (e.g., at least 5%, preferably at least 10%, more preferably at least 15%, and most preferably at least 20% of the ablation threshold). The safety margin can be added to the ablation threshold to define the predetermined threshold of the electric field to be applied to the tissue. The value of the applied electric field described herein may be the value of the electric field in the effective ablation region. The effective ablation region may be, for example, an area covered by or in contact with the ablation portion of the catheter. Therefore, satisfying the ablation threshold of the electric field at least between the ablation electrodes ensures the formation of the desired ablation zone defined by the ablation electrodes.

[0033] The ablation threshold may comprise a value of 400 V / cm at a depth of 5 mm when they are excited by the waveform provided by the generator. In this regard, the electric field applied to the tissue by the pulse should be higher than or equal to 400 V / cm to cause ablation. With a safety margin of 10% of the ablation threshold, the predetermined threshold of the electric field may be selected to be 440 V / cm. Thus, in this example, the electric field to be applied to the tissue should be higher than or equal to 440 V / cm.

[0034] In one example, the predetermined threshold can be based at least in part on the tissue to be ablated. For example, the predetermined threshold can be based on the type of tissue (e.g., cardiac tissue, neural tissue, etc.). In addition, the predetermined threshold can be based on the organ that the tissue surrounds and / or is a part of (e.g., atrium, ventricle, pulmonary vein, etc.) to ensure that the threshold is not set high.

[0035] In one example, the ablation electrode and the generator can be configured to maintain an applied electric field that satisfies an ablation threshold condition. Maintaining can include that the ablation electrode can not be significantly damaged by the applied pulse. The ablation electrode can also be configured to maintain an electric field that satisfies a certain safety margin (e.g., a safety margin of at least 5%, preferably at least 10%, more preferably at least 15%, and most preferably at least 20% of the ablation threshold) that satisfies the ablation threshold condition.

[0036] In one example, the ablation electrode and the generator can be configured to (reliably) maintain a predetermined voltage and / or current of the pulse. The ablation electrode can be configured to maintain a predetermined voltage and / or current for an extended period of time, for example, for applying at least 200 pulses to the tissue, preferably at least 500 pulses, more preferably at least 1000 pulses, and most preferably at least 2000 pulses. The predetermined voltage can include a voltage of at least 1000V, preferably at least 3000V, more preferably at least 3500V, more preferably at least 4000V, and most preferably at least 5000V. In another example, the predetermined voltage can include a voltage between 1000V and 15000V or between 3000V and 10000V, for example. The predetermined current can include a current of at least 5A, preferably at least 10A, more preferably at least 80A, and most preferably at least 150A. However, the predetermined current can also include a current of at least 200A. In another example, the predetermined current may include a current between 5A and 200A, 10A and 100A, for example.

[0037] The pulse duration of the PF energy may include a duration of at least 1 μs, at least 5 μs, at least 10 μs, at least 20 μs, or at least 30 μs. In another example, the pulse duration may include a duration between 5 μs and 100 μs, such as between 10 μs and 75 μs.

[0038] The generator may be configured to apply PF energy according to the voltage and pulse duration as described above.

[0039] The system and in particular the generator may be particularly configured to provide a biphasic pulse comprising a positive portion and a negative portion, the positive portion comprising the positive pulse peak and the negative portion comprising the negative pulse peak. The pulse width is the width of the positive portion (or negative portion). Preferably, but not mandatory, the positive and negative phase complexes will be charge balanced so that the net charge delivered to the tissue is as close to 0 μC as reasonably possible. Alternatively, the charge balance feature may be achieved over the duration of the pulse train. In this case, the net charge of the train will be as close to 0 μC as reasonably possible. The charge balance feature has the potential benefit of minimizing blistering (by reducing the chance of blood electrolysis), arcing (caused by ionization of blood or gas produced by electrolysis), and skeletal muscle stimulation (directly or indirectly through motor nerves). A biphasic pulse that begins with a positive or negative portion is understood to be a positive or negative (biphasic) pulse.

[0040] According to an embodiment, the positive pulse and the negative pulse are separated by an interphase delay. The advantage of the pulse width according to the invention is that the electric field acts on the cell long enough so that a pore is generated by the electric field. The interphase delay can be selected in the region of 100 ns to 100 μs, in particular in the region of 500 ns to 50 μs, so that the negative phase does not eliminate the influence of the positive phase too quickly and the interphase delay is not too long. If the interphase delay becomes too long, the charge balance does not work. The negative phase and the positive phase can have the same amplitude or different amplitudes, as long as a charge-balanced pulse train is achieved.

[0041] According to one embodiment, continuous biphasic pulses are transmitted. The inter-pulse delay between two continuous biphasic pulses can be in the region of 100 μs to 3 ms, in particular in the region of 500 μs and 2.5 ms, in particular in the region of 1.5 ms to 2.5 ms. A continuous biphasic pulse sequence can be considered as a pulse train. Such a pulse train can include 5 to 20, in particular 8 to 12 biphasic pulses. The generator can be configured to receive a medical signal, in particular a signal indicating a heart beat, and synchronize the application of the pulse train with the medical signal, in particular with the heart beat. A pulse train as described above can be applied with each heart beat for 50 to 200 heartbeats, in particular 100 to 150 heartbeats. After a pause of several seconds to several minutes, the above disclosed sequence can be repeated. The peak amplitude of the biphasic pulse can be in the region of 3 kV to 5 kV, in particular in the region of 3.5 kV to 4.5 kV, in particular in the region of 3.8 kV to 4.2 kV.

[0042] In embodiments using biphasic pulses, an interphase delay is determined between two consecutive biphasic pulses, where a biphasic pulse is followed by an inverse biphasic pulse (e.g., a negative biphasic pulse is followed by a positive biphasic pulse). The time between the start of the first biphasic pulse and the subsequent inverse biphasic pulse is the interphase delay, and is also in the range of 1 μs to 100 μs.

[0043] In one example, the catheter can include two or more pairs of ablation electrodes positioned on or along the main axis.

[0044] At least two of these pairs may be configured (or configurable, for example by corresponding switches or other suitable configuration elements, hereinafter, the term "configuration" will be used, but the term "configurable" is implied even if not explicitly stated) for applying separate pulses of electrical energy to tissue in the ablation position. Thus, the catheter may not be limited to applying a single pulse via the terminals of the two ablation electrodes. According to the present invention, the catheter may also include a plurality of ablation electrode pairs, each pair comprising two ablation electrodes, such that each pair can apply separate pulses to the tissue.

[0045] In one example, each pair can be controlled individually so that each pair can apply a separate pulse that is independent of the pulse output of other pairs of the catheter. For example, the catheter can include three electrode pairs. In this example, the catheter can be configured to independently apply pulses from the first pair, the second pair, and / or the third pair. For example, the catheter can be configured to be able to specifically apply pulses from the second pair without applying pulses from the first pair and the third pair. In this example, the catheter can also be configured to achieve independent pulse characteristics of the pulses applied from the electrode pairs. For example, the second pair can apply a pulse with a maximum voltage of 3500V, wherein the first pair and the third pair can apply a pulse with a maximum voltage of 3000V. The separate control of these pairs can be achieved by corresponding circuits in the catheter so that each pair can be individually addressed to provide corresponding individual pulses.

[0046] In one example, the catheter can be configured so that at least two of the (ablation electrode) pairs apply electrical energy pulses to the tissue substantially simultaneously. This can enable a larger ablation area to be covered with a single emission (i.e., a single simultaneous application of pulses) compared to using only one pair of electrodes. In this example, the ablation area can therefore be defined by at least two pairs of ablation electrodes aligned along the main axis of the catheter. For example, the ablation area can be formed at least along the connection path of the ablation electrodes of each of the at least two pairs. In an example, at least two pairs can be adjacent ablation electrode pairs on the main axis of the catheter. For example, this can ensure that an ablation area is formed along the main axis that spans at least from the first ablation electrode of the first pair to the second ablation electrode of the second pair.

[0047] In an example, the catheter can be configured such that at least three, at least four, at least five, or at least six of the pairs (of ablation electrodes) apply pulses of electrical energy to the tissue substantially simultaneously.

[0048] In one example, two or more pairs of ablation electrodes may have one or more ablation electrodes in common. To illustrate the example, two pairs of ablation electrodes may be formed by three ablation electrodes (e.g., first, second, and third ablation electrodes). For example, the second ablation electrode may be shared between the pairs. In this regard, the first pair of ablation electrodes may include the first and second ablation electrodes, wherein the second pair of ablation electrodes may include the second and third ablation electrodes.

[0049] In one example, two or more pairs of ablation electrodes can be positioned along the main axis of the catheter so that the ablation electrodes can be positioned on the tissue along a line (e.g., a straight line and / or a curve). Therefore, the catheter can cause a linear shape of the ablation area (e.g., an elongated shape as described herein) because the ablation area can be defined by the contact positions of two or more pairs of ablation electrodes on the tissue. The ablation area can, for example, correspond to a lesion for therapeutic purposes. Therefore, a linear shaped lesion can be formed by using a catheter according to the present invention. In addition, straight lines and / or curves of ablation areas (e.g., lesions) can be formed in tissue with high flexibility and precision. The linear shape of the ablation area can be formed by shaping the orientation of the portion of the main axis of the catheter that includes two or more pairs of ablation electrodes. The curved linear shape of the main axis can cause the ablation electrode assembly to contact the tissue in a corresponding curved linear sequence. Therefore, by applying pulses for ablation via two or more pairs, a curved linear shape can be formed as an ablation area. The (substantially) straight shape of the main axis can cause the ablation electrode assembly to contact the tissue in a corresponding (substantially) straight sequence. Therefore, by applying pulses for ablation via two or more pairs, a (substantially) linear shape can be formed as the ablation area.

[0050] It is noteworthy that the line and / or linear shape can be formed without moving the catheter during the ablation process, which can significantly reduce the complexity of the procedure. In addition, compared to known methods, it may not be necessary to reposition the main axis during the ablation procedure to form the ablation zone. The shape of the ablation zone can be set by the orientation of the main axis of the catheter.

[0051] As long as contact of the ablation electrode with the tissue is ensured before applying the pulse, an ablation zone can be induced. A linear shape of the ablation zone can be induced, for example, by applying pulses substantially simultaneously via the ablation electrode pair. However, since the catheter can be fixed stationarily at the ablation position, the sequential application of two or more pairs of pulses can also result in a linear ablation zone.

[0052] In one example, two or more pairs of ablation electrodes can be positioned along the main axis so that the application of electrical energy at the ablation location causes a continuous elongated profile without gaps ablated in the tissue. The ablation electrodes can be spaced relative to each other so that the application of pulses by two or more pairs does not leave an area (e.g., a gap) in the ablation zone where the ablation threshold (as described herein) is not received. A gap can be understood as a non-ablation area within the ablation zone. A gap can also be understood as a partial break formed by a non-ablation area passing through the ablation zone, so that at least two separate ablation zones are formed (e.g., if the break in the non-ablated tissue spans along the entire width of the ablation zone). Ensuring that there is no gap formation can be very advantageous because for medical purposes, it may be necessary to form a continuous elongated (linear) profile that can be used as electrical isolation. For example, the ablation zone can be formed so that electrical signals within the tissue cannot pass through the ablation zone. By ensuring that there is no gap formation in the ablation zone, the electrical isolation function can be reliably achieved. Gap formation can be the interaction of the distance between the ablation electrodes, the ablation threshold, and the applied pulses. Thus, gap formation can be suppressed by adjusting the electrical characteristics of the pulse applied between the two ablation electrodes based on the distance between the ablation electrodes, or vice versa. For example, a higher distance between the ablation electrodes may require a higher voltage and / or current in the pulse to induce a sufficiently high electric field so that the ablation threshold condition is met in the tissue. For example, a smaller distance between the ablation electrodes may require a lower voltage and / or current in the pulse to induce a sufficiently high electric field so that the ablation threshold condition is met in the tissue.

[0053] In one example, the catheter may include one or more mapping electrodes for sensing tissue, in particular for sensing intracardiac electrograms. The mapping electrodes may be configured to sense the electrical activity of the tissue. One or more mapping electrodes may be positioned along the main axis of the catheter. For example, the mapping electrode may be positioned in a portion of the main axis of the catheter that includes the ablation electrode. Thus, the mapping electrode may enable sensing of tissue in an effective area to be ablated by or by the ablation electrode. Thus, the mapping electrode may be used to evaluate tissue before applying a pulse (e.g., for determining a medical condition before surgery). On the other hand, the mapping electrode may be used to evaluate tissue after a pulse and / or after a pulse has been applied, for example to determine whether successful ablation of the tissue has occurred. This may be highly advantageous for medical purposes because the mapping electrodes constitute an in-situ detection mechanism for the ablation procedure. Therefore, the present invention may enable the need for a separate detection device or procedure for evaluating ablation to be omitted. Moreover, the mapping electrode may deliver a sensing signal before and / or after ablation without having to move the catheter out of the ablation position.

[0054] In one example, two mapping electrodes on the main axis (e.g., as described with respect to ablation electrodes) can be configured to function as bipolar sensors. In another example, the mapping electrodes on the main axis can be configured to function as monopolar sensors, where the other electrode of the monopolar sensor can reside in another portion of the catheter or in a component connected to the catheter.

[0055] In one example, the catheter may include at least one pair of mapping electrodes, wherein the pair includes two mapping electrodes. In another example, the catheter may include at least two pairs of mapping electrodes, preferably at least three pairs of mapping electrodes, or at least four pairs of mapping electrodes, or at least five pairs of mapping electrodes.

[0056] As described herein, ablation can be performed, for example, for (local) electrical isolation of tissue. In this case, successful ablation can be verified by a signal from one or more mapping electrodes, which indicates that no (significant) electrical activity is occurring in the ablation area. Such verification can be performed, for example, by comparing the signal from one or more mapping electrodes before ablation with the signal from one or more mapping electrodes after the ablation procedure.

[0057] The mapping electrodes can be configured to detect desired (electrical) signals passing through tissue, which can be used to evaluate ablation procedures. However, the mapping electrodes can also be configured to suppress undesirable signals that may be associated with a specific organ, which may crosstalk its (electrical) signals to tissue in the ablation zone, however, the tissue in the ablation zone is irrelevant to the ablation procedure. For example, the electrode area of ​​the mapping electrode can be selected to be limited in size (e.g., compared to the electrode area of ​​the ablation electrode) to suppress the sensing of parasitic signals and enhance local sensing of tissue in the ablation zone. For example, in medical applications of catheters, the ablated tissue can include cardiac tissue (e.g., tissue from the atria, ventricles, etc.). The mapping electrodes can be made small enough so that the electrical activity of cardiac components (e.g., atria, ventricles) that are not associated with the ablation process of the cardiac tissue may not significantly crosstalk with the mapping electrodes.

[0058] For example, the mapping electrodes may be positioned along the main axis of the catheter distal to the ablation electrodes and / or proximal to the ablation electrodes and / or between adjacent pairs of ablation electrodes.

[0059] In some examples, at least one (or all) of the one or more mapping electrodes may have a surface area smaller than at least one (at least two or all) of the at least two ablation electrodes. The mapping electrode may have a length along the catheter axis of less than 3 mm, particularly between 0.5 mm and 2.5 mm, particularly between 0.5 mm and 2 mm, particularly between 1.0 mm and 1.5 mm. The ablation electrode may have a length along the catheter axis of at least 3 mm.

[0060] The sensory assessment of the mapping electrodes may be performed by a computing entity connected to the catheter, which computing entity may receive the signals of the mapping electrodes (eg comprised by a power unit of the system according to the second aspect as described herein).

[0061] In an example of the first aspect of the present invention, the system and / or catheter can be configured to switch the mapping electrode to be used as an ablation electrode; and / or switch the ablation electrode to be used as a mapping electrode. In this regard, the electrodes of the catheter can be used as mapping electrodes once and as ablation electrodes once. In one example, the catheter can include at least a first pair of mapping electrodes and a second pair of mapping electrodes, which can be configured to form at least two bipolar sensors on the main axis. However, at least the first and second pairs of mapping electrodes can also be reconfigured to be used as two ablation electrodes (i.e., as a pair of ablation electrodes). In this regard, the two electrodes in the first pair of mapping electrodes can be reconfigured as a combined ablation electrode. For example, the two electrodes of the first pair can be set at the same polarity so that the first pair forms a lower polarity ablation electrode (e.g., having a lower polarity) of the ablation electrode pair. The two electrodes in the second pair of mapping electrodes can then be reconfigured to be used as the other ablation electrode in the ablation electrode pair. For example, the electrodes of the second pair can be set to the same polarity so that they can form a higher polarity ablation electrode (e.g., higher polarity +). In an example in which at least two adjacent mapping electrodes are arranged as a mapping electrode pair. Two adjacent mapping electrodes can be separated by an inter-mapping spacing of less than 3 mm to serve as ablation electrodes. In particular, two adjacent mapping electrodes are separated by an inter-mapping spacing, which is between 0.2 mm and 2.5 mm, in particular between 0.4 mm and 2.0 mm, and in particular between 0.5 mm and 1.0 mm.

[0062] A pair of ablation electrodes can be arranged on the catheter in such a way that two adjacent ablation electrodes of the pair are separated by a pair distance of at least 3 mm. In particular, two ablation electrodes in a pair of ablation electrodes can be separated by a pair distance between 3 mm and 10 mm, in particular between 3 mm and 6 mm, in particular between 3 mm and 4 mm. Each ablation electrode in a pair of ablation electrodes can be an ablation electrode or two adjacent mapping electrodes arranged as a pair of mapping electrodes and used as ablation electrodes.

[0063] In one embodiment, six pairs of mapping electrodes may be arranged on the catheter to serve as three pairs of ablation electrodes.

[0064] This can enable the same electrode to be used for different purposes while still customizing the electrode configuration for each purpose. In order to achieve adequate tissue ablation, the area of ​​the ablation electrode generally needs to be large enough to maintain the electrical energy of the ablation pulse and effectively apply the electrical energy to the tissue. However, for sensing applications, the area of ​​the mapping electrode should be relatively small, for example, to avoid the effects of parasitic crosstalk signals. By combining two mapping electrodes into a single ablation electrode, an ablation electrode with a wider area can be formed to achieve the boundary conditions for the improved ablation electrode described herein. However, by switching back to the mapping electrode configuration, a smaller electrode area can be enabled for sensing purposes. Therefore, improved ablation and mapping / sensing capabilities can be achieved even when (substantially) the same electrodes (and / or electrode areas) are positioned on the main axis.

[0065] Switching between the mapping configuration and the ablation configuration can be performed by a computing entity that can be connected to the catheter (for example, comprised by a power supply unit of the system according to the second aspect as described herein, which can power the catheter and in particular supply the voltage / current for applying the pulses).

[0066] Notably, features related to switching between mapping electrodes and ablation electrodes may be used independently of other features of the first aspect (eg, whether or not the ablation electrode contacts tissue along the primary axis at the ablation site).

[0067] In one example, at least one mapping electrode can be positioned between two ablation electrodes. This can allow for improved sensing because signals can be picked up within the ablation region because the path between the two ablation electrodes can be ablated as described herein. In one example, at least one mapping electrode pair can be positioned between two ablation electrodes. It is also conceivable that at least one mapping electrode (and / or at least one mapping electrode pair) is positioned between each pair of ablation electrodes or each second pair of ablation electrodes.

[0068] In one example, the mapping electrode pair can be positioned at the distal end of the catheter (e.g., such that no additional ablation electrodes are positioned between the mapping electrode pair and the tip of the catheter). In another example, the mapping electrode pair can be positioned proximally (e.g., such that the ablation electrode is positioned between the mapping electrode pair and the tip of the catheter).

[0069] In one example, the catheter can be configured to allow bridging of pulses on at least one mapping electrode that can be positioned between two ablation electrodes. For example, a pulse applied between two ablation electrodes having a mapping electrode between them can include a higher voltage and / or a higher current (e.g., controlled by a power unit of a system according to the second aspect as described herein) than a pulse applied between ablation electrodes having the same distance between them but without a mapping electrode positioned therebetween.

[0070] In one example, a catheter can include at least one pair of mapping electrodes and a pair of ablation electrodes, wherein the electrical conductors connected to the mapping electrodes are located in a lumen of the catheter that is separate from the electrical conductors connected to the ablation electrodes, and wherein the conductors connected to the mapping and / or ablation electrodes of opposite polarity do not share a lumen. The electrical conductors that electrically connect the mapping electrodes to a generator or mapping system are also referred to as mapping wires. The electrical conductors that electrically connect the ablation electrodes to the generator are also referred to as ablation wires. Mapping wires of different (opposite) polarities can be in separate lumens, whereby mapping wires of the same polarity can share a lumen. This may be even more important for ablation wires of opposite polarity. The ablation wire and / or mapping wire may also be coated with an insulating material.

[0071] The individual lumens can be arranged to maximize the distance between opposite polarities to withstand voltages in excess of 10 kV. Thus, all mapping lines sharing the same polarity can be arranged in a lumen separate from the lumen for mapping lines of opposite polarity. Ablation lines sharing the same polarity can also be arranged in a lumen separate from the lumen for ablation lines of opposite polarity. This can result in four separate lumens for electrical conductors, whereby two lumens for a group of mapping lines having the same polarity as a group of ablation lines can be arranged away from two lumens for grouped mapping lines and ablation lines having opposite polarities.

[0072] This arrangement ensures a safe distance between the mapping wire and the ablation wire to avoid the mapping wire picking up any high voltage from the ablation wire. Picking up high voltage may cause field distortion, ineffective delivery of high voltage and / or shunting during the ablation procedure.

[0073] In an alternative embodiment, mapping and ablation wires of the same polarity may be arranged in a lumen separate from the lumen for mapping and ablation wires of opposite polarity.Such an arrangement may be advantageous in systems using voltages in the lower kV range, where a small catheter profile is desired.

[0074] In one example of the present invention, the catheter can be configured to turn the orientation of the main axis of the catheter. For example, the catheter can include a steering element that allows the main axis of the catheter to be bent. In particular, the steering can be performed in a portion including an ablation electrode and / or a mapping electrode. The steering of the orientation can be performed two-dimensionally. For example, in a substantially undeflected configuration, the main axis of the catheter can coincide with the longitudinal (straight) axis of the catheter. The steering can enable the main axis to be bent relative to the initial (undeflected) longitudinal axis. The steering can enable the curve of the main axis to be formed in a segmented path, which can be described as up to a quarter circle segment, up to a semicircle segment, up to a three-quarter circle segment, and / or up to a four-fifth circle segment. The catheter may not be steerable, so that a closed loop is formed and / or the steerable portion is formed into a three-dimensional structure (e.g., extending out of a plane). Therefore, the main axis can be steered to curl in a specific direction. The tangent of the initial point of the catheter (where the curling basically begins) and the line connecting the initial point of the catheter and the tip of the catheter can span a curling angle that can define the curling. For example, the crimp angle may be up to 5°, up to 10°, up to 45°, up to 90°, up to 135°, up to 180°.In one embodiment, the pull wire is used as a steering element to steer the ablation portion of the catheter, as described above.

[0075] In another example, the steering can be performed specifically in a portion proximal to a portion that includes an ablation electrode and / or mapping electrode. The steering can enable a bend in the main axis to be formed in a segmented path that can be described as up to a quarter circle segment, up to a semicircle segment, whereby the bend is located proximal and near the ablation segment (the segment of the catheter from the most proximal electrode used as an ablation electrode to the most distal electrode used as an ablation electrode). In this example, the ablation segment will be a straight (linear) portion of the catheter, and the adjacent proximal segment will be steerable to form the bend. In this example, the contact between the ablation segment and the tissue can be improved.

[0076] In one example, the stiffness of a distal segment of a catheter comprising an ablation segment can be increased relative to a proximal segment of the catheter, which can further improve the contact between the ablation segment and the tissue. The stiffness of the distal segment comprising the ablation segment can correspond to a Shore hardness of at least 55D, in particular a Shore hardness of at least 72D. The distal segment can include a nitinol wire to increase the stiffness of the distal segment relative to the proximal segment. The diameter of the nitinol wire can be in the range of 0.2mm to 0.8mm, in particular in the range of 0.55mm to 0.65mm. Additionally or as an alternative, at least one of the lumens comprising (one or more) ablation wires and / or (one or more) mapping wires can include an additional polymer tube in the distal segment to increase stiffness.

[0077] In an example of the first aspect, the catheter can be configured to apply a pulse that causes irreversible electroporation of the tissue. For example, a pulsed field application (PFA) treatment can be based on irreversible electroporation (IRE). Therefore, the catheter described herein can be used to apply PFA treatment to tissue.

[0078] In another example, the catheter may be configured such that thermal ablation may not (substantially) be caused by pulses applied to the tissue. For example, radiofrequency ablation (RFA) therapy may rely on the introduction of heat into tissue for its ablation. However, a catheter according to the present invention may be configured to apply pulses for non-thermal ablation of tissue, as thermal ablation of tissue may not always be medically optimal and / or useful.

[0079] In one example, the catheter can include a connector for connecting the electrodes of the catheter to a generator to deliver PF energy to the electrodes. The connector can enable the control lines of the catheter to be safely connected to the generator. For example, the connector can enable reliable connection of the ablation electrode and / or mapping electrode to the power unit. In addition, the connector can enable reliable connection of a steering mechanism (e.g., a steering element) to the power unit to control the steering of the catheter orientation. In an alternative embodiment, the connector can provide connection of the electrodes to a specific mapping system, particularly a mapping system configured to display an intracardiac electrogram.

[0080] An alternative aspect of the invention relates to a catheter for sensing tissue, comprising: at least two mapping electrodes, which are configured to sense the (electrical) activity of the tissue, wherein the mapping electrodes are positioned along the main axis of the catheter, and wherein the catheter is configured so that in the sensing position of the catheter, the mapping electrodes contact the tissue along the main axis. Therefore, the catheter according to the invention can also be used as a sensor device and may not be limited to the use of ablation catheters. In examples of alternative aspects, the ablation electrodes can be omitted. However, all aspects described for the catheter of the first aspect can be applied accordingly to the sensing catheter of the alternative aspect.

[0081] The system and in particular the generator can be configured to apply PF energy to the tissue. For example, the generator may include a power electronics circuit so that the pulse characteristics of the pulses applied via one or more ablation electrodes of the catheter can be set. The generator can also be connected to a computer (e.g., a microprocessor, an ASIC, a computing device, etc.) for controlling the catheter and / or the power electronics circuit. For example, the computer can be used to set specific pulse characteristics that can be processed by the power electronics circuit so that corresponding pulses are applied via the ablation electrodes. The computer can also be configured to apply control instructions to the steering mechanism of the catheter (e.g., to curl the catheter at a desired curling angle). In addition, the computing entity can be configured to receive data from the catheter (e.g., sensing data of the mapping electrode). Therefore, the computer can also be used for signal processing of signals sensed by the mapping electrode (e.g., via a signal processing algorithm). The computer and / or the generator may include a user interface (e.g., a monitor, a keyboard, a touch screen, etc.) so that the user can interact with the system.

[0082] The computer may include one or more storage devices that may store one or more instructions executable by the computer to perform the functions of the systems and / or catheters described herein via corresponding method steps.

[0083] A third aspect relates to a method for ablating tissue, comprising: positioning an ablation catheter at an ablation position so that at least two ablation electrodes located on or along the main axis of the catheter contact the tissue along the main axis; applying electrical energy pulses to the tissue via the at least two ablation electrodes. The catheter of the method may include the catheter according to the first aspect. The method may be performed by a system according to the second aspect.

[0084] A fourth aspect relates to a computer program comprising instructions which, when executed by a computer, a system according to the second aspect and / or a computing device of the system, causes the computer, the system and / or the computing device to perform the method and / or method steps according to the third aspect. In one example, the computer program may include instructions that may cause the execution of various other tasks, control functions and / or data analysis of the catheter and / or system as described herein.

[0085] It should be noted that the method steps as described herein may include all aspects described herein, even if not explicitly described as method steps, but with reference to a catheter (or system or device or computer). Furthermore, the catheters, systems and computer programs as outlined herein may include means for implementing all aspects as outlined herein, even if these may be described in the context of method steps.

[0086] Whether described as method steps, computer programs and / or devices, the functions described herein can be implemented with hardware, software, firmware and / or combinations thereof. If implemented in software / firmware, the function can be stored on a computer-readable medium or transmitted on a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, and communication media include any media that helps to transfer a computer program from one place to another. Storage media can be any available media that can be accessed by a general or special-purpose computer. By way of example and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, FPGA, CD / DVD or other optical disk storage devices, magnetic disk storage devices or other magnetic storage devices, or may be used to carry or store desired program code components in the form of instructions or data structures and any other media that can be accessed by a general or special-purpose computer or a general or special-purpose processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 : Schematic diagram of an exemplary embodiment of a catheter according to the present invention.

[0088] Figure 2 : Simulation results of an exemplary embodiment of a catheter showing the interaction of the exemplary embodiment with tissue for various pulse parameters.

[0089] Figure 3 : An exemplary embodiment of a catheter according to the present invention has a curved main axis.

[0090] Figure 4 : Representation of exemplary catheter ablation locations in a heart model for exemplary ablation treatment of the heart.

[0091] Figure 5 : Representation of exemplary pulses that may be applied by a pair of ablation electrodes of a catheter for tissue ablation.

[0092] Figure 6 : Representation of another exemplary pulse that may be applied by a pair of ablation electrodes of a catheter for tissue ablation.

[0093] Figure 7 : Representation of a 3D voltage map showing conductivity before and after a CTI ablation procedure in the right atrium, and an overview of the pathology in the ablation area.

[0094] Figure 8 : Schematic diagram of an exemplary embodiment of a system according to the present invention.

[0095] Figure 9a , Figure 9b , Fig.9c: Schematic diagram of an exemplary embodiment of the lumen arrangement of a catheter according to the present invention. DETAILED DESCRIPTION

[0096] Figure 1 Schematic diagrams of five exemplary embodiments 1, 2, 3, 4, 5 of a catheter C are shown. Depending on the number of the embodiments, the exemplary embodiments may also be referred to herein as catheter 1, catheter 2, catheter 3, catheter 4, catheter 5. Figure 1 In the figure, a portion of the main axis z of the catheter at the distal end is shown, which may include ablation electrodes and mapping electrodes according to the present invention. The ablation electrodes and mapping electrodes may be positioned on or along the main axis of the catheter in various ways, and the possible positions are not limited to the exemplary embodiments shown.

[0097] To facilitate a general understanding, an exemplary embodiment 3 of a catheter C is discussed first. Figure 1 As shown, the catheter 3 may include six ablation electrodes. In other examples, more or less than six ablation electrodes may be provided. Each two adjacent ablation electrodes may form a pair of ablation electrodes, which may apply electrical energy pulses to tissue for ablation purposes, as described herein. Therefore, a pair of exemplary ablation electrodes A1, A2 are marked on the catheter 3, wherein the remaining ablation electrodes are simply marked as A. However, the characteristics of the ablation electrodes A1, A2 may also be applied accordingly to the other ablation electrodes A, even if not explicitly stated below with respect to each individual aspect.

[0098] The ablation electrode A1 can be connected to a lower polarity -, wherein the ablation electrode A2 can be connected to a higher polarity +. For example, the lower polarity - can be considered as a reference potential (e.g., ground), wherein the higher polarity + can be considered as a terminal for applying an electrical signal relative to the reference potential. Thus, a defined electrical pulse can be applied between the ablation electrodes of a pair of ablation electrodes A1, A2 via the catheter C. The same applies to the two pairs formed by the four additional ablation electrodes A.

[0099] In addition, the defined electrical pulses can be shaped to achieve pulsed field ablation (PFA) treatment of tissue. Therefore, the ablation electrode can be configured to apply PFA pulses to apply PFA energy to the tissue. In a preferred example, the ablated tissue may include cardiac tissue. In this case, ablation may include causing irreversible electroporation of cardiac tissue via PFA treatment. In this case, the ablated tissue can be considered as damage.

[0100] The ablation electrodes A1, A2, A of the catheter can be positioned with a series of alternating polarities along the main axis, as shown in catheter 3. Therefore, between each pair of consecutive ablation electrodes (A1, A2), (A2, A1), ..., electrical pulses can be applied to the surrounding tissue along the main axis z of the catheter C. In one example, the catheter C can apply pulses via the ablation electrodes substantially simultaneously. Therefore, the catheter C can constitute a disposable linear ablation catheter. For example, the pulses applied by the ablation electrodes A1, A2, A can be shaped so that one (simultaneous) application of the pulses can be sufficient to ablate the surrounding tissue. Therefore, as described herein, tissue can be ablated in a linear (elongated) shape. In other examples, simultaneous pulse sequences (e.g., pulse trains) can also be applied.

[0101] The ablation electrodes A1, A2, A may include a specific ablation electrode length d2 relative to the main axis z of the catheter. The ablation electrodes A1, A2, A may, for example, include annular electrodes, wherein the specific ablation electrode length d2 may scale the area of ​​the annular electrodes. The distance between two ablation electrodes A1, A2, A on the main axis z may be referred to herein as the pair spacing dE1 (understood as the distance from one end of the ablation electrode to the nearest end of the adjacent ablation electrode). The pair spacing dE1 may be an important parameter for shaping the pulse to be applied, because the pair spacing dE1 may affect the electric field strength applied to the tissue based on a given voltage difference between a pair of ablation electrodes.

[0102] In one example, the inter-pair spacing dE1 may be at least less than 10 mm, preferably at least less than 5 mm, more preferably at least less than 4 mm, most preferably at least less than 3.5 mm, such as about 3 mm, which can ensure effective PFA treatment effect.

[0103] In an example, a particular ablation electrode length d2 may be at least less than 20 mm, at least less than 10 mm, at least less than 4 mm, at least less than 3.5 mm, or about 3 mm, for example. The ablation electrodes of catheter C may include the same or different lengths.

[0104] Catheter C may also include mapping electrodes. In this regard, catheter 3 may, for example, include mapping electrodes M1, M2 located at the distal end of catheter C and / or mapping electrodes M1, M2 located at the proximal end of catheter C. The mapping electrodes M1, M2 of the catheter at each end may be configured as bipolar sensors for sensing surrounding tissue. The mapping electrodes M1, M2 may be disabled during the application of ablation pulses via the ablation electrodes. However, the mapping electrodes may also be active for sensing during the application of pulses. This may be implemented, for example, for catheter 3 because the mapping electrodes are not located between the ablation electrodes, so that sensing may be feasible during the application of ablation pulses.

[0105] The mapping electrodes M1, M2 may include a specific mapping electrode length d1 relative to the main axis z of the catheter. The mapping electrodes M1, M2 may include ring electrodes, wherein the specific mapping electrode length d1 may scale the area of ​​the ring electrodes. The distance between two mapping electrodes M1, M2 on the main axis z may be referred to herein as the inter-mapping spacing dE2.

[0106] In an example, the inter-marking spacing dE2 may be at least less than 3 mm, at least less than 2 mm, at least less than 2 mm, or less than 0.5 mm. In catheter 3, the inter-marking spacing dE2 may comprise approximately 1 mm.

[0107] In an example, the specific mapping electrode length d1 may be at least less than 3 mm, at least less than 2 mm, at least less than 1 mm, or at least less than 0.5 mm. This may ensure high-resolution mapping. In the catheter 3, the specific mapping electrode length d1 may include about 1 mm.

[0108] Thus, the catheter C according to the present invention may include means for ablation (eg, ablation electrodes A1 , A2 , A2 ) and means for sensing surrounding tissue (eg, mapping electrodes M1 , M2 ).

[0109] The catheter C according to the five embodiments 1, 2, 3, 4, 5 is particularly suitable for providing biphasic PF energy as described above. The catheter according to embodiments 1, 2, 3 is also suitable for providing monopolar PF energy.

[0110] Subsequently, exemplary embodiments of the catheter 1 will be discussed. The catheter 1 may constitute an example in which the catheter includes mapping electrodes that can be switched to serve as ablation electrodes and vice versa. In this regard, the catheter 1 may include several pairs of mapping electrodes, wherein: Figure 1 Six mapping electrode pairs are depicted as an example. A first pair of mapping electrodes A1, A1' and a second pair of mapping electrodes A2, A2' are Figure 1 is marked. The inter-mapping spacing dE2 of the catheter 1 can be, for example, about 0.5 mm (preferably <1 mm) to ensure high-resolution mapping. The specific mapping electrode length d1 of the catheter 1 can include about 1.5 mm (preferably <2 mm). When used as a mapping electrode, the mapping electrode A1 can represent the lower polarity - of the bipolar sensor formed by the first pair, wherein the mapping electrode A1' can represent the higher polarity + of the bipolar sensor formed by the first pair. Moreover, in this case, the mapping electrode A2 can represent the lower polarity - of the bipolar sensor formed by the second pair, wherein the mapping electrode A2' can represent the higher polarity + of the bipolar sensor formed by the second pair. This component can be beneficial because high-resolution mapping along the main axis z can be performed via the mapping electrode configuration.

[0111] However, the polarity depicted in catheter 1 represents the polarity of the electrodes of catheter C when switched so that they can be used as ablation electrodes. This can be performed by a system (as described herein) that can connect electrodes to specific polarities, where the polarity can be driven / controlled by a power unit of the system (e.g., which can include a PFA generator for applying pulsed field ablation pulses). In this case, a first pair of mapping electrodes A1, A1' can be used as a first ablation electrode of an ablation electrode pair. A second pair of mapping electrodes A2, A2' can be used as a second ablation electrode. To achieve this functionality, electrodes A1, A1' can both be switched to a lower polarity - (e.g., representing a reference potential), where electrodes A2, A2' can both be switched to a higher polarity + (e.g., the signal potential of the pulse). Thus, an ablation electrode pair having an inter-pair distance / spacing of dE1 can be formed. The inter-pair spacing dE1 of catheter 1 can, for example, include approximately 3 mm (such as a reference potential). Figure 1 Other values ​​of those described in Example 3 are also possible).

[0112] Therefore, catheter C can play a dual role of mapping the target tissue and PF ablation of the target tissue.

[0113] In the ablation configuration, two adjacent electrodes of the same polarity, such as the combined electrode (A1, A1') and the combined electrode (A2, A2'), will have an equivalent length, which can be greater than the length of one of the individual electrodes. For example, a combined ablation electrode including electrodes A1, A1' will have an equivalent length, which can include twice the specific mapping electrode length d1 plus the inter-mapping spacing dE2. Therefore, the equivalent length can be defined as: 2×d1+dE2. In the example of catheter 1, the equivalent length can therefore be 3.5mm (i.e., 2×1.5mm+0.5mm=3.5mm). When the voltage applied in the exemplary dimensions of catheter 1 exceeds 2500V, preferably 3500V, no gaps are left in the lesion contour of, for example, cardiac tissue. This is because the inter-pair distance dE1 can be designed to match the applied PFA waveform so that an electric field exceeding the threshold required for irreversible electroporation (IRE) (e.g., of cardiac cells) is induced in the tissue.

[0114] Catheter 2 is similar to catheter 1, but shows an example in which the inter-mapping spacing dE2 between mapping electrodes A1, A1' (and A2, A2') is increased to approximately 1 mm, similar to catheter 3. This configuration may be beneficial for longer target areas. Due to the increased electrode spacing of the mapping electrodes, the voltage applied via the pulse may need to be slightly higher than the voltage of catheter 1. Similarly, when the applied voltage exceeds 3000V (preferably 3500V), no gaps are left in the lesion contour. This is because the inter-pair spacing dE1 can be designed to match the applied PFA waveform so that together they produce an electric field that exceeds the threshold required for irreversible electroporation IRE.

[0115] In contrast, catheter 3 can also be used to cover a longer target area. For the size of catheter 3, when the voltage applied by the pulse exceeds 2500 V (preferably 3500 V), no gaps are left in the lesion contour. This is because the inter-pair spacing dE1 can be designed to match the applied PFA waveform so that the electric field induced in the tissue exceeds the threshold required for irreversible electroporation IRE.

[0116] Catheters 4 and 5 are similar to catheter 3 (ie, include pure ablation electrodes), but have additional mapping electrodes M1, M2 placed between the active (PFA) ablation electrodes A1, A2 (wherein Figure 1 ). For example, they can include six ablation electrodes that form three mutually exclusive pairs P1, P3, P5. However, pairs P2 and P4 also produce a field sufficient for ablation, so that a substantially gapless ablation zone along the main axis (z) of catheters 4, 5 can be produced. In addition to the mapping electrode pairs distal and proximal to the ablation electrodes, two further pairs of mapping electrodes M1, M2 can be provided, so that the mapping electrode pairs M1, M2 are located between each mutually exclusive ablation electrode pair P1, P3, P5. For example, a benefit of such a configuration can be that they can provide mapping information at a position between the active ablation electrodes A1, A2. In addition, the hardware of the generator and catheter can be simplified compared to catheters 1 and 2, because no switching may be required to combine the two mapping electrodes M1, M2 into one active PFA ablation electrode, as required for catheters 1 and 2. However, a higher voltage may be required to bridge the active PFA ablation electrodes A1, A2 with the mapping electrodes M1, M2 between them.

[0117] For example, for catheter 4, the system may be programmed to apply a voltage >3000V to ablation electrode pairs P1, P3, P5, and a voltage >3500V to ablation electrode pairs P2 and P4.

[0118] exist Figure 1 In the example of the catheter 4, the catheter 4 has a specific ablation electrode length d2 of about 3 mm, a specific mapping electrode length of about 1 mm, and a mapping distance dE2 of about 1 mm. The distances dE1 between the ablation electrode pairs P1, P2, and P3 are about 3 mm, respectively. The distances dE1 between the pairs of P2 and P4 are about 9 mm, respectively.

[0119] exist Figure 1In the example of , catheter 5 has a specific ablation electrode length d2 of about 3 mm, a specific mapping electrode length of about 1 mm, and an inter-mapping spacing dE2 of about 1 mm. The inter-pair distances dE1 of ablation electrode pairs P1, P2, and P3 are respectively about 3 mm. Compared with catheter 4, the inter-pair distances dE1 of P2 and P4 can be reduced, for example, to about 5 mm. Due to the reduced inter-electrode spacing, for catheter 4, the system can be programmed to apply a voltage of >2500V to electrode pairs P1, P3, and P5, and a voltage of >3000V to electrode pairs P2 and P4.

[0120] It should be noted that due to the high voltages required for ablation, applying ablation pulses between electrodes M1, M2 of a pair of mapping electrodes should be avoided. This may result in high electric fields, which may result in electrolysis (which may result in bubble formation) and / or arcing. In addition, the ablation electrodes should be configured to maintain the high electric fields caused by the PFA pulses having the voltages described herein so that they are not damaged when the (PFA) pulses are applied to the tissue.

[0121] Figure 2 Simulation results of an exemplary embodiment of a catheter are shown, which show the interaction of an exemplary catheter with tissue for various pulse parameters. The simulation is based on finite element analysis. It is worth noting that Figure 2 Shows Figure 1 Simulation results for catheters 1-5. Column numbers represent the simulation results for the corresponding exemplary catheters (e.g., column 1 represents catheter 1, column 2 represents catheter 2, and so on). Each row represents the voltage applied to the ablation electrode pair in the simulation. The results are based on a static simulation of the electric field, where the lower polarity (-) is set to ground and the higher polarity (+) is set to the corresponding voltage, shown for each row. In the static simulation, the voltages applied to the ablation electrode pairs are applied simultaneously. The potentials of the (unlabeled) mapping electrodes (if they are not used as ablation electrodes) are set to floating potentials. The tissue surrounding the catheters in the simulation is selected to represent the conductivity of cardiac tissue (e.g., atrial tissue).

[0122] For the simulation, an ablation threshold of 400 V / cm was chosen, since the ablation threshold of 400 V / cm can be assumed to be the IRE threshold of the cardiac tissue. Therefore, the legend showing the magnitude of the electric field is limited to the ablation threshold. Therefore, values ​​above the ablation threshold are also shown with the same tone as the ablation threshold of 400 V / cm. For medical and / or technical purposes, it may be sufficient to show areas exceeding the ablation threshold, since it indicates that these areas are ablated. Therefore, the shape of the areas exceeding the ablation threshold can represent the shape of the lesion L generated by the catheter.

[0123] As in Figure 2As can be seen in the simulation results, the catheter 1-5 with its ablation electrode A and mapping electrode M can form a lesion L of elongated shape regardless of the indicated applied voltage (from 2000V to 4000V). In addition, there is no gap formation within the lesion L, so that electrical isolation of the tissue can be ensured. As the voltage applied at the ablation electrode increases, the length of the lesion L in the z direction (for example, along its main axis) can increase slightly. In addition, the voltage increase can slightly increase the lateral extent of the lesion L in the y direction. As can be seen in the simulation results, the lesion contour can include various depressions in the lateral extent, so that a slightly curved or undulating but elongated lesion contour can be generated in the tissue.

[0124] Thus, a catheter according to the present invention may form an elongated lesion L having a length of at least 20 mm, at least 30 mm, at least 40 mm, at least 50 mm, at least 60 mm, at least 70 mm and / or at least 80 mm.

[0125] In an example, the lesion length can be increased by adding more pairs of ablation electrodes to the main axis of the catheter. For example, the catheter can also include at least 8 pairs, at least 10 pairs, at least 20 pairs, at least 30 pairs of ablation electrodes.

[0126] The catheter according to the present invention can form a lesion with a maximum lesion width of at least less than 7 mm, at least less than 8 mm, at least less than 9 mm, at least less than 10 mm, at least less than 12 mm and / or at least less than 14 mm. However, the maximum lesion width can also be at least less than 16 mm, at least less than 18 mm and / or at least less than 20 mm.

[0127] In another example, a catheter according to the present invention can form a lesion L having a (maximum) length of at least 2 times the maximum lesion width (e.g., measured perpendicularly to its length), at least 3 times the maximum lesion width, at least 4 times the maximum lesion width, at least 5 times the maximum lesion width, at least 7 times the maximum lesion width, and / or at least 10 times the maximum lesion width. The lesion can have a substantially linear shape.

[0128] Lesions L can be generated by the catheter on various tissues associated with the heart, for example, on the Crista Terminalis Isthmus CTI. In another example, lesions L can be generated on the inner wall of the heart (e.g., the inner wall of the atrium, ventricle, etc.). In another example, lesions L can be generated on the outer wall of the heart (e.g., the outer wall of the atrium, ventricle, etc.). In short, lesions L can be generated in the endocardium, myocardium and / or epicardium of the heart. This can be achieved because the ablation catheter according to the present invention can be formed as a uniaxial ablation catheter, which can be easily positioned in the heart and on the outer wall of the heart.

[0129] Figure 3 FIG. 4 shows an exemplary embodiment of a catheter C with a curved main axis according to the present invention. It is worth noting that the electrodes of the catheter 4 are arranged at Figure 3 As can be seen, the portion of the main axis z that includes the mapping electrode M and the ablation electrode pair P1-P5 can be curled. As described herein, the main axis z can be turned to curl in a particular direction relative to the starting point 300. A tangent line to the starting point 300 of the catheter C and a line connecting the starting point 300 with the tip T of the catheter can span a curl angle α, which can define the amount of curl. Figure 3 In the example, the value of the curl angle α is about 100°. However, the curl angle can be (limited to) at most 5°, at most 10°, at most 45°, at most 90°, at most 135°, at most 180°. The curl of the main axis z can span a two-dimensional plane.

[0130] It is also conceivable that the catheter C according to the present invention may not be a steerable configuration. In this case, the curl may, for example, not be present in the catheter C. In another example, the catheter may include a preset curl that may not be changed compared to the steerable example of the catheter C.

[0131] Figure 4 A representation of exemplary catheter ablation locations in a heart model for an exemplary ablation treatment of the heart is shown. In particular, a steerable catheter C according to the present invention is shown, which is deployed on the terminal crista isthmus CTI at the tricuspid annulus TVA. In addition, the heart model shows the locations of the superior vena cava SVC, the right atrium RA, the fossa ovalis, the coronary sinus CS, and the inferior vena cava IVC. At such locations, a single PFA energy delivery according to the present invention can achieve complete heart conduction block.

[0132] Figure 5 A representation of exemplary pulses that may be applied by a pair of ablation electrodes of a catheter for tissue ablation is shown. Figure 5 , channel 1 depicts the pulse voltage V, which is scaled down by a factor of 100 (e.g., 40V on channel 1 represents a pulse voltage of 4000V). The pulses can be biphasic, having a positive portion and a negative portion. The amplitude pulses can peak at approximately +4300V and approximately -4000V. Channel 2 depicts the resulting current I displayed as a voltage, which is scaled down by a factor of 10 (e.g., 4V on channel 2 represents a pulse current of 40A). The exemplary pulses shown on the oscilloscope display can represent a PFA waveform applied by an ablation electrode, having a peak of approximately +40A and another peak of approximately -35A. In some examples, the pulse amplitude can be symmetrical around zero.

[0133] Figure 6 A representation of another exemplary pulse that may be applied by a pair of ablation electrodes of a catheter for tissue ablation is shown. Figure 6 The channel scaling corresponds to Figure 5 Therefore, Figure 6 The exemplary pulse of may represent another type of PFA waveform applied by the ablation electrode. As can be determined from channel 1 (based on ΔH: 38.4V), the voltage amplitude of the pulse is ±3840V, which is slightly less than the reference Figure 5 The voltage amplitudes outlined above are similar, but more symmetrical about zero. Therefore, this PFA waveform may be suitable for a pair of ablation electrodes that do not have a mapping electrode between them. In this case, the lower voltage (compared to Figure 5 compared) may be sufficient because the mapping electrodes do not have to be bridged by the pulse.

[0134] It is worth noting that the PFA waveform applied by the ablation electrode may include a positive half-wave and a negative half-wave, such as Figure 5 and Figure 6 As shown. Each half-wave can have a rectangular, sinusoidal and / or toothed shape. However, other shapes are also conceivable. The maximum voltage of the PFA waveform may be between 1500V and 5000V. The pulse duration of the PFA waveform may be between 1μs and 100μs. The positive half-wave and the negative half-wave may each include approximately half of the pulse duration. Instead of a single pulse, a pulse train with a specific pulse interval may also be applied. PFA waveforms may have an increased safety profile because they may avoid collateral tissue such as nerves, coronary arteries, epicardial fat, esophagus, etc. Such PFA waveforms may also produce smaller thermal effects than other energy modalities (e.g., such as RFA therapy and / or cryoablation therapy).

[0135] The delivered PFA waveform can be matched to the electrode configuration of the catheter so that the desired therapeutic effect is achieved without the need to reposition or move the catheter.

[0136] The PFA waveform may be adjusted via a power unit that may be connected to the catheter. Via corresponding power electronics included in the power unit, the desired PFA waveform may be shaped and transmitted to the ablation electrode.

[0137] Figure 7 is a representation of a 3D voltage map showing conductivity before (left) and after (right) an ablation procedure and a pathological view of the ablation area. In the left figure, a pre-ablation 3D voltage map from a preclinical study is shown. The 3D voltage map shows a left anterior oblique LAO view of a heart slice. The LAO view shows the superior vena cava SVC, tricuspid annulus TVA, inferior vena cava IVC, coronary sinus ostium CSOS and the guide catheter. For the ablation procedure, the deployment of catheter C is similar to Figure 4 Ablation locations of the catheters are shown in FIG.

[0138] exist Figure 7In the right figure of , a post-ablation 3D voltage map of a preclinical study is shown. It can be seen that the result of the ablation is a clear heart block at the CTI (at the right atrium) in one shot without moving the catheter. The heart block can be seen because the lower right area of ​​the 3D map indicates that no electrical activity has occurred. Therefore, the linear lesion L that can be ablated by the catheter C can, for example, be used to block the parasitic circular electrical activity at the CTI that can be seen in the left image.

[0139] For the ablation procedure, PFA energy delivery took less than 30 μs to complete to achieve the conduction block shown. The mapping electrodes of catheter C were also used to confirm the block.

[0140] Figure 7 The middle view of shows the pathological overview of a single-shot lesion. The superior vena cava SVC, tricuspid annulus TVA, coronary sinus ostium CS OS, inferior vena cava IVC (and tricuspid stenosis TS) are marked. In addition, the location of the lesion L created by the catheter of the present invention is shown.

[0141] Figure 8 A schematic diagram of the entire system according to an embodiment of the present invention is shown. The generator 100 is configured to generate PF energy and the corresponding waveform as described above. The generator 100 is connected to the catheter 200 via a connector 300. The connector 400 can be configured as a cable. The catheter includes a proximal handle 210, a distal ablation portion 220, and a proximal catheter portion 230 between the handle 210 and the distal ablation portion 220. The distal ablation portion includes 6 ablation electrodes arranged in three pairs.

[0142] Figure 9a , 9b 9c show schematic diagrams of exemplary embodiments of lumen arrangements of catheters according to the present invention. Figure 9a , 9bEach of 9c shows a cross section of the distal ablation portion 220 of the catheter 200. Each exemplary catheter 200 includes two lumens 501, 503 that accommodate two pull wires 502, 504 that serve as steering elements (steering wires). One electrode 550 is shown in the cross section, whereby the electrode is arranged as a ring electrode on the catheter shaft 540. The electrode 550 is a mapping electrode connected (not shown) to one of the mapping wires 512, 514 or an ablation electrode connected (not shown) to one of the ablation wires 522, 524. The mapping wires 512, 514 and the ablation wires 522, 524 serve as electrical conductors that electrically connect the corresponding mapping electrodes and ablation electrodes of the catheter 200 to the generator 100 or to the mapping system (not shown) via the connector 400. The space 530 between the individual lumens 501, 503, 511, 513, 521 and 523 is filled with an electrically isolating material, preferably the same material as the catheter shaft 540. Each ablation wire 522, 524 is also covered with an electrical insulator. The mapping wire 512 is located in a separate lumen 511 from the mapping wire 514 of opposite polarity. The same applies to the ablation wire 522 and the ablation wire 524 of opposite polarity.

[0143] Figure 9a A schematic diagram of a cross-section of an ablation portion 220 of a catheter 200 including three pairs of mapping electrodes and four pairs of ablation electrodes is shown. Mapping wires 512, 514 and ablation wires 522, 524 of opposite polarity are arranged in separate lumens 511, 513, 521 and 523. The mapping wires 512, 514 do not share a lumen with the ablation wires 522, 524. In addition, the ablation portion 220 of the catheter 200 includes an additional central lumen 561 for a nitinol wire 562. The nitinol wire 562 is arranged in the ablation portion 220 to enhance the stiffness of this portion of the catheter. This additional lumen 561 for the nitinol wire 562 can be used, for example, Figure 9a-9c In all arrangements shown.

[0144] exist Figure 9a In the illustrated embodiment, the lumens 511, 513, 521, 523 for the mapping wires and the ablation wires are arranged in a planetary configuration, whereby each lumen 511, 513, 521, 523 is arranged at the same distance from the center of the cross section. This arrangement maximizes the distance between opposite polarities to withstand voltages exceeding 10 kV. In addition, it ensures a safe distance between the mapping wires and the ablation wires to avoid the mapping wires picking up any high voltage from the ablation wires. Picking up high voltages may cause field distortion, ineffective delivery of high voltages, and / or shunting during ablation procedures.

[0145] Figure 9bAn alternative arrangement of lumens 511, 513, 521, 523 for mapping and ablation lines is shown. In this embodiment, the distance between opposite polarities is also maximized. Mapping line 514 and ablation line 522 share a polarity opposite to that of mapping line 512 and ablation line 524. The X-shaped arrangement of lumens 511, 513, 521, 523 improves the ability of ablation segment 220 to deflect in two opposite directions relative to a plane oriented through the center of the cross section and parallel to the straight line position of lumens 511, 513, 521, 523.

[0146] Fig.9c A pie-shaped arrangement of lumens 511, 513, 521, 523 for mapping and ablation wires is shown. In this arrangement, mapping wires 512, 514 for four mapping electrodes are shown. Again, mapping wire 514 and ablation wire 522 share a polarity opposite to that of mapping wire 512 and ablation wire 524.

[0147] In summary, the present invention can enable the treatment of cardiac disorders such as atrial flutter, persistent atrial fibrillation and / or ventricular tachycardia by catheter ablation linear lesions of the corresponding tissues described herein. The system according to the present invention can solve the limitations of the prior art by generating linear lesions without the need for catheter repositioning. The system according to the present invention may include a catheter, a power unit (including a generator) and / or required accessories. The catheter can be positioned once at the target location and does not need to be repositioned until another target location is tried. Accessories (e.g., cables, foot switches, monitors, keyboards, etc.) can connect the catheter to the generator, and / or can facilitate the operator to use the system. The generator of the power unit can deliver a PFA waveform with a sufficiently high peak voltage to achieve the desired IRE threshold for a given electrode configuration and geometry. The matching of the waveform with the catheter configuration can ensure effective treatment delivery without the need for catheter repositioning. In most cases, the system according to the present invention can achieve the desired treatment results by delivering only one PFA energy delivery emission. The mapping electrodes of the catheter can then be used to confirm the treatment results.

[0148] It will be apparent to those skilled in the art that, in light of the above teachings, many modifications and variations of the described examples and embodiments are possible. The disclosed examples and embodiments are presented for illustrative purposes only. Other alternative embodiments may include some or all of the features disclosed herein. Therefore, the present invention is intended to cover all of these modifications and alternative embodiments, which may fall within the true scope of the present invention.

Claims

1. A catheter (C, 200) for ablating tissue using pulsed field (PF) energy, configured to be connected to a high voltage generator for generating PF energy, wherein the catheter comprises: at least two ablation electrodes (A1, A2), in particular at least six ablation electrodes, configured to apply PF energy to the tissue; wherein the catheter is configured such that in the ablation position of the catheter, the ablation electrodes (A1, A2) contact the tissue along the main axis (z) of the catheter, wherein the catheter comprises at least two separate electrical conductors for connecting the electrode to the high voltage pulse generator for generating PF energy, wherein the at least two separated electrical conductors are adapted to deliver a waveform (W) having a peak voltage of at least 1000 V, in particular at least 3000 V, to the electrodes, and wherein the ablation electrodes of the catheter are spaced apart such that when they are excited by the waveform, the electric field within the cardiac tissue exceeds a strength of 400 V / cm at a depth of 5 mm.

2. The catheter according to claim 1, wherein The catheter is configured to ablate the tissue along a portion of the main axis, wherein the portion spans at least a distance (dE1) between the ablation electrodes.

3. The catheter according to claim 1 or 2, wherein: The catheter is configured such that an elongated profile (L) is ablated into the tissue.

4. The catheter according to any one of claims 1 to 3, wherein: At least one of the ablation electrodes is located at a sidewall of the catheter such that it is spaced apart from the tip of the catheter.

5. The catheter according to any one of claims 1 to 4, wherein: The catheter comprises two or more pairs of ablation electrodes (P1 , P2, P3, P4, P5) positioned along the main axis (z).

6. The catheter according to claim 5, wherein: The catheter is configured such that at least two of the pairs (P1, P2, P3, P4, P5) apply electrical energy pulses to the tissue substantially simultaneously and / or such that at least two of the pairs apply separate electrical energy pulses to the tissue at the ablation location.

7. The catheter according to claim 5 or 6, wherein: The two or more pairs of ablation electrodes are positioned along the major axis such that application of electrical energy at the ablation location results in a continuous elongated profile (L) without ablated gaps in the tissue.

8. The catheter according to any one of claims 1 to 7, wherein: The catheter includes one or more mapping electrodes (M1, M2) for sensing the tissue.

9. The catheter according to claim 8, wherein The catheter is configured to switch the mapping electrodes to function as ablation electrodes; and / or Switch the ablation electrode to function as a mapping electrode.

10. The catheter according to claim 9, wherein At least two adjacent mapping electrodes are arranged as a pair of mapping electrodes with an inter-mapping spacing of less than 3 mm to serve as ablation electrodes.

11. The catheter according to claim 10, wherein Two pairs of mapping electrodes are arranged on the catheter to function as a pair of ablation electrodes, whereby a first pair of adjacent mapping electrodes are arranged at an inter-pair distance (dE1) from the second pair of adjacent mapping electrodes.

12. The catheter according to claim 11, wherein Six pairs of mapping electrodes are arranged on the catheter to serve as three pairs of ablation electrodes.

13. The catheter according to any one of claims 8 to 12, wherein: The catheter includes at least one pair of mapping electrodes and a pair of ablation electrodes, wherein the electrical conductors connected to the mapping electrodes are located in a lumen of the catheter that is separate from the electrical conductors connected to the ablation electrodes, and wherein the conductors connected to the mapping electrodes and / or ablation electrodes of opposite polarity do not share a lumen.

14. The catheter according to any one of claims 8 to 13, wherein Two adjacent mapping electrodes are separated by an inter-mapping distance of between 0.2 mm and 2.5 mm, in particular between 0.4 mm and 2.0 mm, in particular between 0.5 mm and 1.0 mm.

15. The catheter according to any one of claims 8 to 14, wherein The mapping electrode has a mapping electrode length (d1) less than 3 mm, in particular between 0.5 mm and 2.5 mm, in particular between 0.5 mm and 2 mm, in particular between 1.0 mm and 1.5 mm.

16. The catheter according to any one of claims 1 to 15, wherein: Two adjacent ablation electrodes are separated by an inter-pair distance (dE1) of at least 3 mm, in particular between 3 mm and 10 mm, in particular between 3 mm and 6 mm, in particular between 3 mm and 4 mm.

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