JP6113780B2 - Ablation catheter and method for electrically insulating heart tissue - Google Patents

Description

  The present invention relates to ablation catheters and methods for electrically insulating (isolating, isolating, isolating) cardiac tissue. More particularly, the present invention relates to a method for complete circular electrical isolation of a pulmonary vein ostium at the entrance to the left atrium.

  The pulmonary vein is a known source or atrial arrhythmia and atrial fibrillation, and the boundary between the pulmonary vein mouth (small hole) and the left atrium (pulmonary sinus) is once atrial fine. It is a known region with slow electrical conductivity that can be part of the substrate that maintains it when it begins to move. Complete electrical insulation of the pulmonary sinus can cure the disease in about 75% of patients. Electrical isolation through the myocardium can be achieved by causing permanent tissue damage that causes replacement of the heart tissue by fibrous tissue. In contrast to the myocardium, fibrous tissue blocks the propagating electrical wavefront, thereby causing electrical insulation.

  Various methods are currently used for pulmonary sinus isolation. Such methods include ablation by heating, eg, radio frequency ablation, or using ultrasound or laser energy, and cryoablation.

  All of the techniques described above have disadvantages and drawbacks. Some are very time consuming, some require complex techniques and very expensive thick and poorly maneuverable catheters, and some often have late recurrence. It only causes temporary (temporary) electrical isolation with Some are at risk from potential thrombus formation or are often fatal between the left atrial cavity and the esophagus due to esophageal fistula, ie damage to the esophageal wall very close to the posterior left atrial wall Leaks, which can cause

International Publication No. 2004 / 039273A2

  The object of the present invention is a safe, efficient and / or easy-to-use catheter for use in ablation procedures (therapy, surgery), in particular of the pulmonary vein stoma (mouth) at the entrance to the left atrium It is to provide a catheter that can be used for complete circular electrical isolation (electrical isolation).

  To achieve that objective, an ablation catheter according to the present invention comprises an elongate member having a proximal end and a distal end, the distal end comprising at least one electrode and the length of the distal end. It is configured to apply a high energy electric shock (shock) from a plurality of locations along its length, and the distal end is curved. The curved distal end of the elongate member provides good contact between the tissue to be treated and the electrode. Preferably, the curvature of the distal end of the elongated member is the surface curvature of the tissue to be treated such that the curved distal end is substantially complementary to the surface of the tissue to be treated. It can be adapted to.

  The present invention effectively isolates (isolates) a predetermined region of tissue by using a DC ablation technique that has multiple shock delivery locations located in close proximity to the tissue to be treated, due to the curvature of its distal end. Based on the discovery that it is possible. These locations extend along a predetermined path on the tissue, and by applying a sufficiently high electric shock to the distal end, the tissue region that touches the delivery location is made permanent (permanent). It becomes nonconductive.

  In addition, by using multiple shock delivery locations in close contact with the tissue to be treated, to provide electrical isolation between the two regions of the heart tissue. The need for multiple positioning of the catheter is reduced. With the device according to the invention, a relatively long length of heart tissue can be treated with a single operation and the treatment time (surgery time) is reduced.

  As used herein, the term high energy electric shock (electric shock) is a 200-500 joule shock, preferably a 250-400 joule shock applied for about 5 ms, more preferably, Should be interpreted as a shock of about 350 joules. By applying (acting) the shock from a plurality of locations along the distal end, the energy is distributed over the length, limiting the energy per unit of length. This reduces the risk of explosions and sparks associated with DC ablation near the electrodes.

  In order to be able to deliver a shock to the distal end of the catheter, the elongated member is subjected to a high energy current from the proximal end of the elongated member to the distal end with the electrode. Appropriate conducting means (conducting means) are provided for transmission. Preferably, the guide means has a guide core provided on the elongated member.

  According to a preferred embodiment of the present invention, the distal end of the elongate member extends in a circular segment. Since the cardiac tissue surface is generally curved, the distal end provided with at least one electrode and the tissue are provided with a substantially complementary shape in the form of a circular segment at the distal end. The contact between is strengthened. The circular segment allows for a close fit of the distal end, for example, to at least a portion of the cross-section of the pulmonary vein ostium. Preferably, the distal end of the elongated member extends in a substantially circular shape. The distal end is thereby looped. By using a distal end that extends in a circular segment or in a loop, a tubular tissue surface, eg, a vein, is treated along the cross section in a single operation. Can be done. By providing the tubular tissue with a non-conductive cross-section, the tissue region extending adjacent to the non-conductive tissue is insulated (isolated). Preferably, the radius of the circular segment is 5 to 25 mm, preferably 10 to 20 mm.

  More preferably, the curvature of the distal end is adjustable, and more specifically the diameter of the circular segment is adjustable. This allows for a custom fit of the distal end of the elongate member to the surface of the tissue to be treated regardless of the diameter or curvature of the tissue.

  According to a further preferred embodiment of the invention, the curved distal end of the elongate member extends in a plane at an angle with respect to the axis of the elongate member. For example, when treating the inner wall of a blood vessel, the catheter is advanced along the longitudinal axis of the blood vessel. If the electrode on its distal end extends in a plane at an angle with respect to the axis of the elongate member, it is effective on the inner wall of the vessel at virtually any longitudinal position within the vessel. It is possible to touch. Preferably, the curved distal end of the elongate member extends in a plane substantially perpendicular to the axis of the elongate member.

  This is advantageous if the plane in which the distal end extends is adjustable. Here, the proximal length of the distal end of the elongate member is preferably manipulable. By using this manipulable end, it is possible to adjust the direction of the plane in which the curved distal end extends relative to the surface of the tissue to be treated. Preferably, the elongate member is adapted to bend at a position proximal to the curvature of the distal end. This allows for effective adjustment of the plane in which the distal end extends.

  According to a first preferred embodiment of the ablation catheter according to the present invention, the distal end of the elongate member comprises a plurality of electrodes extending at different positions along the length of the distal end. In this embodiment, shock delivery locations on its distal end are formed by separate electrodes. Preferably, the electrodes extend at a mutual distance of 3-12 mm, preferably at a mutual distance of about 5 mm. It has been found that a small mutual distance increases the uniform energy transfer to the tissue and this results in a closed circuit of electrically non-conductive tissue during treatment. Preferably, these electrodes extend in a circular segment with substantially equal arc distances, thereby allowing, for example, effective insulation (isolation) of tissue in a blood vessel.

  According to a further preferred embodiment of the invention, the distal end comprises 5 to 24 electrodes, preferably comprises 8 to 16 electrodes, more preferably comprises 10 electrodes. It has been found that by using 10 electrodes, optimal insulation (isolation) of blood vessels (vessels), for example, pulmonary veins, can be realized.

  According to a further preferred embodiment, the electrodes have the same polarity. This allows an effective distribution of electrical energy from the electrode provided at its distal end to the tissue to be treated.

  It is further advantageous that the distribution of the electrical energy radially outwards is enhanced when the electrodes extend in a circular segment, or more preferably in a circular shape. The electrodes preferably engage tissue with their surfaces oriented radially outward relative to the circular segment, so that most of the electrical energy is transferred to the tissue. It is further advantageous if the electrodes have a substantially smooth surface, i.e. they do not have sharp edges. This prevents unwanted current concentrations around the electrodes.

  According to a further preferred embodiment of the invention, the at least two adjacent electrodes are configured to act on different voltages. Preferably, the applied shock voltage alternates between adjacent electrodes. This, combined with the flow of electrical energy between two adjacent electrodes using different voltages, allows for the radially outward distribution of electrical energy with the same polarity used for each of those electrodes. When at least a portion of the electrical energy flows between the electrodes, substantially all of the tissue extending between the electrodes is exposed to the electrical energy to cause an insulating action (isolating action, isolating action, isolating action). action) is increased.

  According to a further preferred embodiment of the invention, the elongate member is electrically conductive means (conductive) configured to conduct a high current separately to each of the electrodes from its proximal end to its distal end. Means). This reduces the possibility of high energy concentrations near any of the individual electrodes in the event of an electrode malfunction. Each of these electrodes is preferably powered separately using a known appropriate power source.

  According to a second preferred embodiment of the ablation catheter according to the invention, the elongate member comprises one electrode extending over substantially the entire length of the curved distal end. In this embodiment, the shock delivery location is formed by a single elongated electrode. Preferably, the electrode allows bending of its distal end, thereby allowing adjustment of the bending or direction of its distal end. More preferably, the electrode comprises a coil. The coil electrode is flexible and allows a curved distal end. Furthermore, the use of a coil increases the maneuverability of the distal end, for example to adjust the curvature of the distal end.

  According to a further preferred embodiment of the invention, the elongated member has a first position where the elongated member extends substantially linearly and a second position where the distal end of the elongated member curves. And can be moved between. The linear orientation of the distal end in its first position allows the catheter to be effectively advanced, for example, through the sheath and into the heart. When reaching the tissue to be treated, the elongated member can be moved to a second position where its distal end is curved, preferably a second position extending in a circular segment.

  When using a sheath to advance the elongate member through the vasculature, the elongate member can be advanced through the sheath when the sheath is in place. The sheath extends coaxially to the elongate member and surrounds the elongate member. This prevents deflection of the distal end in its first position. Preferably, the distal end of the elongate member is manufactured from a material that can bend. More preferably, the distal end includes a shape memory material. As the elongate member is advanced from the sheath, movement from the first position to the second position occurs automatically.

  It is possible to use an external electrode as an indifferent electrode, for example an electrode applied to the patient's skin. However, this results in high skeletal muscle activity when delivering a shock. According to a further preferred embodiment of the invention, the catheter further comprises an indifferent electrode extending proximal to the electrode. This significantly reduces the effects of electrical shock on adjacent tissues, such as skeletal muscle. Furthermore, the integral indifferent electrode makes the configuration of the catheter according to the present invention compact. Preferably, the indifferent electrode comprises a coil, more preferably the coil extends coaxially to the elongated member. Preferably, the indifferent electrode extends a distance of 3-10 cm from the most proximal shock delivery position, and more preferably, the indifferent electrode is approximately about the most proximal shock delivery position. Extend a distance of 5 cm.

  It is advantageous if the catheter is provided with a sheath and the sheath is provided with the indifferent electrode. When using a sheath, preferably a steerable sheath, the distal end of the sheath is usually advanced into the left atrium. Subsequently, access to the left atrium for the catheter according to the invention can be performed by advancing the elongate member through the sheath. If the indifferent electrode, preferably a coil, is provided at the distal end of the sheath, the indifferent electrode is preferably located at a position where a small amount of skeletal muscle tissue is used, eg, right It extends into the atrium or inferior vena cava.

  It is further advantageous to use a known localization system to place the catheter in the heart. Thereby, the electrode or electrodes provided at its distal end can be placed in the heart. Such a system further allows for accurate mapping of the heart and allows for accurate deployment of its curved distal end onto the heart tissue to be treated.

  According to a further preferred embodiment of the invention, the catheter is configured to apply a high energy shock according to the heart rate (in response to the heart rate). This allows cardioversion, ie the end of atrial fibrillation. Preferably, the catheter is configured to apply a shock outside the vulnerable phase in both the atrial and ventricular heartbeats. This allows cardioversion without inducing ventricular fibrillation. Preferably, the electrode, or more preferably at least one of the plurality of electrodes, on the distal end is configured to monitor heart rate.

  Preferably, the catheter of the present invention is provided at its proximal end with a suitable connector for connecting the catheter to known measuring means for monitoring heart rate.

  More preferably, the indifferent electrode extends at least partially in another chamber (preferably in the right atrium), and the electrode on its distal end is near the left atrium. Is disposed on the elongated member. This enhances cardioversion because the electrodes on the distal end, the indifferent electrode, and both poles extend into different chambers.

The present invention further provides a method for electrically isolating (insulating) heart tissue comprising:
An ablation catheter comprising an elongated member having a proximal end and a distal end, the distal end being provided with at least one electrode, the distal end being the length of the distal end Providing an ablation catheter that is configured to apply a high energy electric shock from a plurality of locations along the surface, the distal end of which is curved;
-Advancing the ablation catheter into the heart tissue;
-Contacting the distal end with the heart tissue; and
Applying a high energy electrical shock to the heart tissue from a plurality of locations along the length of the distal end.

  With the above method according to the present invention, a plurality of shock delivery locations are placed in intimate contact with the tissue to be treated, wherein at least two locations extend with a predetermined mutual distance. To do. The curvature of the distal end provided with at least one electrode provides such close contact. Preferably, the curvature of the distal end of the elongate member is complementary to the surface of the tissue to be treated.

  With the electrode extending into one path on the tissue, a high energy electrical shock is delivered from the plurality of shock delivery locations of the electrode to the distal end of the elongate member. As a result, tissue in adjacent regions of the electrode becomes nonconductive. It will be appreciated that the above method according to the present invention provides a method for electrically isolating a region of tissue.

  Preferably, the step of applying the high energy electric shock includes the step of applying a shock of 200 to 500 joules, preferably 250 to 400 joules, and more preferably about 350 joules for a predetermined period (predetermined time). Including. 350 Joules has been found to be sufficient for complete and permanent (permanent) electrical isolation of heart tissue. Preferably, the predetermined period is less than 10 ms, more preferably less than 5 ms, and even more preferably, the period is about 1 ms. Because the shock is delivered from multiple locations in a short period of time, the energy per unit length is small enough to prevent sparking and bubble formation associated with conventional DC ablation.

  According to a preferred embodiment, the distal end comprises a plurality of electrodes, the electrodes having the same polarity. In this embodiment, the shock delivery position is formed by at least two separate electrodes spaced a certain distance apart. By applying a shock from a plurality of electrodes having the same polarity, it is possible to optimally distribute electric energy. Preferably, the step of applying the high energy electric shock includes the step of applying the shock simultaneously from a plurality of electrodes. This further increases the distribution of electrical energy to the tissue to be treated.

  It is further advantageous if the step of applying a high energy electric shock includes the step of applying a shock having a different voltage from at least two adjacent electrodes along the length of the distal end. The difference in voltage between two adjacent electrodes results in current flow between the electrodes. Along with the flow of the electrodes of the same polarity, at least a part of the electric energy flows between adjacent electrodes. This ensures that substantially all tissue extending between the electrodes is exposed to electrical energy, resulting in a closed path of the tissue being treated (treated). To. Preferably, the shock voltage applied from these different electrodes is alternating.

  According to another embodiment, the elongate member comprises one electrode extending along substantially the entire length of its distal end. By bringing the tissue surface into contact with the elongated electrode, eg, a coil, a closed circuit is formed. A shock is applied to the tissue from a plurality of positions along the length of the electrode.

  According to a preferred embodiment, contacting the heart tissue includes contacting the tissue along a path. Here, the step of applying the shock includes the step of forming a closed circuit of electrically non-conductive tissue. The electrode extends along a path on the tissue prior to the application (application) of the shock. When multiple electrodes are used, the distance between the electrodes is such that all tissue extending between two adjacent electrodes is exposed to sufficient electrical energy, resulting in a non-conductive tissue closure. So small enough.

  Preferably, the step of contacting the heart tissue includes adapting the curvature of the distal end of the elongate member to the surface of the heart tissue to be insulated. With a steerable distal end, a shock delivery location along the distal end, eg, a plurality of electrodes, can be placed in intimate contact with the tissue so that from at least one electrode More effective energy transfer to the tissue occurs. Preferably, the distal end of the elongate member extends in a circular segment and the contacting step includes adapting the diameter of the circular segment to the surface of the heart tissue. The diameter of the circular segment is adjusted to the diameter of the tissue to be treated, for example the inner diameter of a vessel (blood vessel).

  It is also advantageous if the contacting step comprises adjusting the plane in which the curved segment extends relative to the surface of the heart tissue. Enables a close fit of the distal end of the elongate member to the surface, for example, if the surface of the tissue extends at an angle with respect to the longitudinal axis of the elongate member Thus, it is possible to adjust the surface of the electrode (plane).

  Allowing both the diameter of the circular segment and the angle of the circular segment to the axis of the elongate member to be adjustable can ensure intimate contact between the electrode and tissue.

  According to a further preferred embodiment of the present invention, the catheter comprises a sheath, and advancing the catheter through the vasculature includes advancing the catheter through the sheath. Here, the elongated member is movable between a first position where the elongated member extends substantially linearly and a second position where the distal end of the elongated member curves. . The elongate member is then moved from its first position to a second position by advancing the elongate member out of the sheath. In its first position, the elongate member is limited in deflection by the sheath that allows easy advancement of the elongate member through the sheath. As the elongate member is moved distally out of the sheath, the elongate member moves toward the second position to allow for a close fit of the electrode to the tissue. .

  According to a further preferred embodiment of the invention, the step of applying (applying) the high current comprises the step of using the electrode provided on the catheter as the indifferent electrode. Preferably, the electrode comprises a coil. This results in a compact configuration. Furthermore, external indifferent electrodes, such as skin patches, are associated with adverse effects on the patient (bad effects, negative effects, negative effects). When using external electrodes, skeletal muscle contracts vigorously during its shock, often causing patient displacement on the catheterization table. The use of indifferent electrodes on the catheter minimizes this problem.

  According to a further preferred embodiment of the invention, the heart tissue has a pulmonary vein opening, preferably a pulmonary vein opening near the entrance to the left atrium. The pulmonary vein is a well-known source of atrial arrhythmia and atrial fibrillation. With the method according to the present invention, an effective method for isolating the vein (blood vessel) from the atrium is provided. Preferably, the step of contacting the heart tissue comprises contacting the ostium (mouth) of the pulmonary vein with its distal end along the cross-section of the vein. In this way, the cross-section of the pulmonary vein is rendered non-conductive and the tissue regions extending adjacent to the non-conductive boundary are separated.

  More preferably, the step of advancing to the heart tissue includes advancing the sheath with an indifferent electrode proximate to a distal end extending into the atrium. For example, providing an indifferent electrode in the form of a coil on the sheath allows a close relationship between the distal end electrode and the indifferent electrode, minimizing the impact of shock on adjacent tissue. It becomes. Preferably, the indifferent electrode is placed in a position where there is little skeletal muscle tissue in use, for example, the right atrium or the inferior vena cava.

  A further preferred embodiment of the present invention further includes the step of monitoring a heart beat (heart beat) and applying the shock based on the heart beat. ECG is measured at least before applying the shock. The ECG and, in particular, the ECG P-wave is preferably measured using an electrode provided at the distal end of the catheter according to the invention. However, other measurement methods known to those skilled in the art can also be used. However, measuring P waves using external measurement methods is difficult in some situations. If the P wave is measured using an internal electrode, for example, an electrode provided on a catheter or a separate catheter provided on the heart, a more reliable measurement is possible.

  Preferably, the shock is applied for a predetermined time to a heartbeat that is outside the unstable phases of both the atrium and the ventricle. Normally, only the unstable phase of the ventricle is thought to prevent ventricular fibrillation. In accordance with the method of the present invention, the energy shock is also applied (applied) outside the unstable phase of the atrium to prevent atrial fibrillation that occurs when the shock is applied. This further allows for effective cardioversion. Preferably, the energy shock is applied to or before the ECG QRS-complex.

  The present invention is illustrated by the following figures which show preferred embodiments of the device according to the invention, which are not intended to limit the scope of the invention.

It is a figure showing roughly the ablation catheter concerning the present invention. It is a figure which shows schematically the catheter in the left atrium. It is a figure which shows schematically the catheter in a blood vessel in a cross section. FIG. 6 is a perspective view schematically showing a curved tissue region. It is a figure which shows schematically distribution from the electrode of an electrical energy. FIG. 2 is a diagram schematically showing a pig heart. It is a figure which shows the result of the test implemented with respect to the pig. It is a figure which shows the result of the test implemented with respect to the pig. It is a figure which shows the result of the test implemented with respect to the pig. It is a figure which shows the result of the test implemented with respect to the pig.

  FIG. 1 shows a catheter 1 according to the present invention. The catheter 1 comprises an elongate member 2 with a proximal end (not shown) and a distal end 21. The distal end 21 of the elongated member is curved. In this embodiment, the distal end 21 extends in a circular segment that forms a loop or annulus. The distal end 21 extends in a plane II that forms an angle with respect to the longitudinal axis I of the elongated member 2. The distal end 21 is provided with a plurality of electrodes 6, in this case 10 electrodes 6. The electrode 6 extends with a relative distance of 5 mm.

  The distal end 21 of the elongate member 2 is operable, which allows the physician to adjust the plane II of the electrode 6. This facilitates placement of the electrodes on the tissue to be treated, as will be described in more detail below. Also shown is a steerable sheath 3, which allows effective advancement of the catheter 1 through the vasculature (vasculature). In this embodiment, the sheath 3 is provided with an indifferent electrode in the form of a coil 7. The coil 7 is arranged coaxially with respect to the sheath.

  The distal end 21 forming the loop is preferably made of a material that can bend. When the elongate member 2 is drawn into the sheath 3 in the direction indicated by reference numeral III, the distal end 21 is deformed to extend substantially linearly. In this first position, the distal end 21 is housed within the sheath 3. This results in a compact configuration. In its first position, the elongate member 2 can be advanced through the sheath 3 to the tissue to be treated. As the catheter 1 is advanced to its tissue, the elongate member 21 is advanced out of the sheath 3 and the distal end 21 deflects back to the second position, as shown in FIG.

  In FIG. 2, the catheter 1 is shown in place in the left atrium 8 of the heart. The sheath 3 has advanced through the diaphragm 81. As a result, the coil 7 extends into the right atrium. In order to isolate the tissue region from the pulmonary vein 82, the distal end 21 of the elongate member 2 is advanced within the vein 82 such that the electrode 6 contacts a wall along the cross-section of the vein 82. To do.

  In order to facilitate the placement of the electrode 6 on the wall of the vein 82, the distal-most end 22 can be manipulated, and the plane of the electrode 6 indicated in FIG. It can be adjusted in the direction shown.

  With the steerable distal end 22 it is also possible to adjust the diameter of its circular segment from which the electrode 6 extends, as schematically shown in FIG. As in FIG. 3, as the distal end 21 is advanced within the vein 82, the electrode 6 may not make intimate contact with the tissue. In order to achieve a close fit of the distal end 21 provided with the electrode 6 to its wall, its diameter can be adjusted. The electrode 6 is moved in the direction indicated by the symbol VI in order to achieve a close contact between the wall of the vein 82 and the electrode 6.

  As shown in FIG. 3, the distal end 21 provided with the electrode 6 forms a closed loop over the cross section of the vein 82. The electrode 6 extends over the closed loop on the inner wall of the vein and insulates (isolates) the tissue region extending adjacent to the distal end 21 (below and above the plane of FIG. 3). Isolating).

  Referring back to FIG. 2, when the electrodes are positioned in close proximity to the tissue 83 to be treated, about 350 joules of high energy electrical shock (electric shock) occurs in about 5 ms. Added to the electrodes. Since ten electrodes 6 are used, each of the electrodes 6 delivers about 35 joules of electric shock (shock). This has been found to be sufficient to render tissue 83 extending in the vicinity of the electrode permanently non-conductive and isolate the vein 82 from the left atrium 8. ing.

  In order to achieve good insulation between the tissue regions, the distance between the two electrodes 6 is sufficient for all tissue 83 extending between the electrodes 6 to induce non-conductivity. Small enough to ensure exposure to high electrical energy. This ensures proper insulation.

  As an example, the curved surface of the tissue 8 is shown in FIG. In order to achieve intimate contact between the electrode 6 and the tissue 83 to be treated, the distal end 21 is curved in a complementary fashion to the curvature of the tissue 8. Accordingly, all of the illustrated electrodes are in contact with the tissue 83. Application of electric shock (shock) through the electrode 6 renders the tissue indicated by reference numeral 83 non-conductive. Thereby, the structure | tissue shown by the code | symbol 84a is insulated from the structure | tissue shown by the code | symbol 84b.

  In order to increase the distribution of electrical energy from the electrode 6 to its tissue, the polarity of all the electrodes 6 is the same. Furthermore, the catheter 1 is configured to synchronize the shock from the electrode 6. Each of these electrodes is provided with a known separate power source. This results in a distribution of the electrical energy indicated by the reference E1 in FIG. The term radial is interpreted with respect to an axis I when the distal end 21 extends in a plane II perpendicular to the longitudinal axis I of the elongated member, as shown in FIGS. It should be.

  In FIG. 5, the electrodes 6 are arranged so as to deliver an AC voltage shock between the electrodes. The electrode 6a is configured to deliver a 3500V shock, while the electrode 6b is configured to deliver a 3000V shock. This voltage difference between adjacent electrodes results in the flow of electrical energy E2 between the adjacent electrodes 6a, 6b. This ensures that the tissue extending near the region 21a between the electrodes 6 is also well exposed to electrical energy E2.

The invention is not limited to the illustrated embodiment, but extends to other embodiments that are within the scope of the appended claims. While embodiments with multiple electrodes are shown, it will be understood that a single elongate electrode can be used that can be placed in close proximity to the tissue to be treated.
(Example)

  Next, the present invention will be further described with reference to examples.

  FIG. 6 shows a sketch of the reconstructed geometry of the pig's left atrium. The left atrium (LA), three pulmonary vein openings (RPV, IPV and LPV), and a portion of the left atrial appendage (LAA) are shown. DC ablation according to the present invention was performed at the mouth of the right RPV and the left pulmonary vein LPV (ostia).

  The purpose of the ablation procedure is to destroy all important atrial myocardium inside the mouth of the pulmonary vein (ostium). Such disruption results in a dramatic reduction in the local electrogram as measured using an endocardial (intracardiac) catheter.

  FIG. 7A shows an electrocardiogram I of a pig heart before ablation. RA and RV are electrocardiograms of the right atrium and right ventricle. La1 to La8 are recordings by a lasso catheter at various positions in the atrium.

  The catheter according to the present invention was placed inside the ostium of the right pulmonary vein at four different locations. One of these positions is schematically illustrated using dotted lines in FIG. For each position, 200 joules of DC shock were delivered through 10 electrodes of the catheter (20 joules per electrode). After these shocks, as can be seen in FIG. 7B, only the complete ostium of the right pulmonary vein shows a very small electrogram amplitude, which is electrically active atrial tissue / atrium. It means that the muscle was destroyed by the shock.

  FIG. 8A shows pre-recordings for the second pig similar to those shown in FIG. 7A. In this case, two subsequent 200 joule shocks were applied to the tissue. Also here, as can be seen in FIG. 7B, almost all atrial signals are extinguished, which means that the stoma is damaged.

Claims (15)

A DC ablation catheter comprising an elongated member having a proximal end and a distal end comprising:
The distal end comprises a plurality of electrodes extending to different locations along the length of the distal end;
The elongate member is movable between a first position where the elongate member extends substantially linearly and a second position where the distal end of the elongate member curves and loops. ,
Electrodes extend in loop with the relative distance of 3 to 12 mm,
The electrode is configured to apply a high energy electric shock for DC ablation from multiple locations along the length of the distal end ;
The electrode is provided so that a high-energy electric shock of 200 to 500 joules is applied within a predetermined period shorter than 10 ms,
The elongate member comprises conducting means for conducting a high energy current from a proximal end of the elongate member to a distal end with the electrode for delivering a high energy electric shock. and have, DC ablation catheter.   The DC ablation catheter of claim 1, wherein a distal end of the elongate member extends in a circular segment.   The DC ablation catheter of claim 1 or 2, wherein a distal end of the elongate member extends in a substantially circular shape. The DC ablation catheter according to claim 2 or 3, wherein the radius of the circular segment is 5 to 25 mm .   The DC ablation catheter according to any of claims 1 to 4, wherein the curvature is adjustable. 6. A DC ablation catheter according to any preceding claim, wherein the curved distal end of the elongate member extends in a plane at an angle with respect to the axis of the elongate member.   The DC ablation catheter according to any of claims 1 to 6, wherein the plane in which the distal end extends is adjustable.   The DC ablation catheter according to claim 1, wherein the electrodes have the same polarity.   9. A DC ablation catheter according to any of claims 1 to 8, wherein at least two adjacent electrodes are configured to apply a shock at different voltages. DC ablation catheter according to any of the preceding claims , wherein the electrodes extend at a relative distance of 5 mm. It said distal end comprises 5 to 24 amino electrodes, DC ablation catheter according to claim 1.   12. The elongate member comprises conducting means configured to conduct high current to each of the electrodes separately from the proximal end to the distal end. DC ablation catheter.   The DC ablation catheter according to any of claims 1 to 12, further comprising an indifferent electrode extending proximal to the distal end.   14. A DC ablation catheter according to claim 13, wherein the indifferent electrode comprises a coil. The catheter is provided with a sheath,
The DC ablation catheter according to claim 13 or 14, wherein the sheath is provided with the indifferent electrode.

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