JP4925210B2 - Electrode catheter - Google Patents

Description

  The present invention relates to an electrode catheter comprising an electrode at the catheter tip.

  The pulsation of the heart is performed by sequentially stimulating the muscles of the heart with electrical signals periodically generated from a part of the heart. However, if an abnormality occurs in the flow of this electrical signal, the heart cannot beat accurately. This is so-called heart disease.

An electrode catheter is known as a medical device used for diagnosing or treating cardiac arrhythmia. An electrode catheter is usually composed of a catheter body, a control handle connected to the proximal end of the catheter body, and a catheter distal end connected to the distal end of the catheter body. A plurality of ring-shaped electrodes are mounted.
When diagnosing cardiac arrhythmia using such an electrode catheter, the electrode catheter is inserted into the blood vessel from the catheter tip, and the catheter tip is pressed against the inner wall of the heart to measure the internal potential of the heart To do. For this reason, it is important that the distal end portion of the catheter can be fitted to the shape of the measurement site.

  2. Description of the Related Art Conventionally, an electrode catheter for measuring a potential at a site such as a pulmonary vein of a heart has been proposed that has a catheter tip formed in a loop shape (see, for example, Patent Document 1). By forming the distal end portion of the catheter in a loop shape, the inner peripheral portion of the blood vessel can be simultaneously measured in the radial direction.

  14 is a perspective view showing a catheter tip (mapping assembly) constituting the electrode catheter according to Patent Document 1, and FIG. 15 (1) is a perspective view schematically showing the shape of the catheter tip. (2) is an explanatory view when the distal end portion of the catheter is viewed from the direction of arrow D in FIG. 1 (1), and FIG. 15 (3) is an EE arrow view of FIG.

  The catheter distal end portion 90 is constituted by a substantially straight proximal end region 91, a generally circular main body region 92, and a substantially straight distal end region 93, and is formed on the distal end side (intermediate portion 95) of the catheter body. It is connected.

  The proximal end region 91 of the catheter tip 90 is formed in a generally straight shape and extends in the distal direction of the catheter.

  The body region 92 of the catheter tip 90 is generally circular, but strictly speaking it is a spiral that extends slightly distally. A plurality of ring electrodes (not shown) are mounted on the main body region 92.

A distal end side region 93 of the catheter distal end portion 90 is formed in a substantially linear shape, and extends from the distal end of the main body region 92 in a tangential direction (distal direction) of a circle that is the shape of the main body region 92. The tip 93A of the tip side region 93 is the distal end of the catheter. The distal end side region 93 is made of a coil spring and functions as a mini guide wire.
JP 2003-111740 A

However, the electrode catheter according to Patent Document 1 has a problem that the shape of the catheter distal end portion 90 is easily changed when the catheter distal end portion 90 is pushed into the blood vessel.
For example, as shown in FIG. 16A, the distal end side region 93 that functions as a mini-guide wire receives a drag force P1 from the blood vessel wall (a drag force acting in an arbitrary direction on a plane including the main body region 92). As a result, the loop forming the main body region 92 is easily opened as shown in FIGS.
The drag P1 from the blood vessel wall is most easily applied to the tip 93A (distal end) of the tip side region 93. This is because the distal end 93A of the distal end side region 93 is in point contact with the blood vessel wall, and is easily deformed by dragging the distal end 93A.
In addition, as shown in FIG. 17 (1), the distal end portion of the main body region 92 receives a drag force P2 from the blood vessel wall (a drag force acting in a direction perpendicular to the plane including the main body region 92). As shown in 2), the loop forming the main body region 92 is easily opened.
Further, as shown in FIG. 17 (3), the intermediate portion of the main body region 92 receives a drag force P3 from the blood vessel wall (a drag force acting in a direction perpendicular to the plane including the main body region 92). As shown in 4), the main body region 92 is easily bent (the angle α formed with the base end region 91 changes).

  When the shape of the catheter tip 90 changes, the ring electrode mounted on the main body region 92 cannot be brought into contact with the target site in the blood vessel, and as a result, an accurate potential can be measured. become unable.

  In response to such a problem, the applicant forms a linear proximal region extending in the distal direction and extending to the distal end, and a loop from the distal end to the proximal region. However, an electrode catheter provided with a catheter tip having a spiral main body region extending in the proximal direction has been proposed (Japanese Patent Application No. 2007-210563).

  According to this electrode catheter, the proximal end of the relatively strong body region is used as the distal end of the catheter, and the distal end of the relatively weak body region is retracted from the distal end of the catheter in the proximal direction. Therefore, the degree of deformation of the entire body region can be reduced, and when the catheter tip is pushed into the blood vessel with the catheter tip as the head, the catheter tip becomes difficult to deform and an accurate electric potential is measured. be able to.

By the way, the electrode catheter is usually inserted into the lumen of a sheath (sheath introducer) placed in advance and pushed into the blood vessel (near the target site) by being pushed out from the distal end opening of the sheath.
Here, the distal end portion of the catheter having a predetermined shape (for example, a spiral shape) extends linearly in the lumen of the sheath and is restored to the shape before insertion after being pushed out from the distal end opening of the sheath. is required.

The present invention has been made based on the above situation.
It is an object of the present invention to provide a catheter tip that is difficult to deform when it is pushed into the blood vessel with the catheter tip at the head, and is capable of measuring an accurate electric potential. Provided is an electrode catheter capable of reliably restoring the shape of the catheter tip portion, which is linearly extended in the lumen of the sheath, to the shape before insertion after being pushed out of the sheath tip opening when inserted into the sheath. There is.
Another object of the present invention is to provide an electrode catheter that can be smoothly pushed into a blood vessel while maintaining the shape of the catheter tip.
Still another object of the present invention is to provide an electrode catheter capable of simultaneously measuring potentials at a plurality of locations (circumferential portions) along the longitudinal direction of a blood vessel.

As a result of intensive studies to solve the above purpose,
(1) When the catheter is pushed into the blood vessel starting from the catheter tip, it is the portion located at the distal end of the catheter that is most susceptible to drag from the blood vessel wall;
(2) The main body region of the distal end portion of the catheter is less likely to be deformed in the vicinity of the proximal end, and is more likely to be deformed closer to the distal end.
(3) Therefore, the proximal end of the high-strength body region that is relatively difficult to deform is used as the distal end of the catheter, and the distal end of the relatively strong body region that is relatively easily deformed is proximal from the distal end of the catheter. By retracting in the direction, the degree of deformation of the entire body region when receiving drag from the blood vessel wall can be reduced,
(4) By providing a portion extending in the distal direction (the direction opposite to the direction in which the main body region extends) from the front end of the main body region as the front end side region of the catheter front end portion, It has been found that the catheter tip can be reliably restored to the shape before insertion, and the present invention has been completed based on such knowledge.

That is, the electrode catheter of the present invention includes a catheter main body having at least one inner hole, a control handle connected to the proximal end side of the catheter main body, and a distal end side of the catheter main body. An electrode catheter comprising a catheter tip having an inner hole communicating with at least one of the holes, and a plurality of ring-shaped electrodes attached to the outer periphery of the catheter tip,
The catheter tip includes a linear proximal region extending distally to the distal end;
A helical body region extending proximally from the distal end (tip of the proximal region) and forming a loop around the proximal region;
A distal region extending distally from the distal end of the body region ,
The distal end of the distal end region, which is a free end, is located proximal to the distal end of the proximal region, which is the distal end of the catheter .

  In the electrode catheter according to the present invention, it is preferable that the main body region of the distal end portion of the catheter is formed so that its loop diameter increases as it extends in the proximal direction (closer to the distal end).

In the electrode catheter of the present invention, the main body region of the distal end portion of the catheter has a generally circular first loop formed around the proximal end region,
A substantially circular second loop formed around the proximal region on the proximal side (tip side) of the first loop;
The diameter of the second loop is preferably larger than the diameter of the first loop.

  In this case, it is preferable that the ring electrodes mounted on the outer periphery of the second loop are arranged in a plurality of pairs. Hereinafter, one constituted by a pair of ring electrodes is referred to as a “counter electrode”.

  In the electrode catheter of the present invention, it is preferable that a spherical tip electrode is attached to the tip of the catheter tip.

  The electrode catheter according to claim 1 includes a linear proximal region extending in the distal direction and extending to the distal end, and a proximal direction while forming a loop from the distal end to the proximal region. And a distal end region extending distally from the distal end of the body region, and a proximal end of the relatively strong body region is disposed at the distal end of the catheter. The tip of the body region having a relatively low strength is retracted in the proximal direction from the distal end of the catheter. As a result, the degree of deformation of the entire main body region can be reduced.

In addition, the main body region of the catheter distal end portion has a spiral shape that extends while forming a loop around the proximal side region, so that the proximal side region acts as a central axis of the loop (spiral). Shape stability can be further improved.
Therefore, according to the electrode catheter of the first aspect, when the catheter tip is pushed into the blood vessel with the catheter tip as the head, deformation of the catheter tip can be sufficiently suppressed and prevented. As a result, the ring-shaped electrode mounted on the main body region of the catheter tip can be brought into contact with the target site in the blood vessel, and as a result, an accurate potential can be measured.

  According to the electrode catheter according to claim 1, the potentials at a plurality of locations (inner peripheral portions) along the longitudinal direction of the blood vessel are simultaneously measured by the plurality of ring-shaped electrodes attached to the body region of the catheter tip. Can do.

  According to the electrode catheter of the first aspect, the distal end portion of the catheter constituting the electrode catheter has the distal end side region extending in the distal direction from the distal end of the main body region, so that the electrode catheter is placed in the lumen of the sheath. When inserted into a blood vessel through insertion, the catheter tip in a state extending linearly in the lumen of the sheath can be reliably restored to the shape before insertion after being pushed out from the distal end opening of the sheath. .

  According to the electrode catheter of the second aspect, since the main body region of the catheter tip portion constituting the electrode catheter is formed so that the loop diameter increases as it extends in the proximal direction, the shape of the catheter tip portion is maintained. However, it can be pushed into the blood vessel smoothly.

  That is, the body region of the distal end portion of the catheter is likely to be deformed because it is closer to the free end as it is closer to the distal end, and is more likely to be deformed as the loop diameter is larger. In the electrode catheter according to claim 2, Near the distal end of the catheter that is susceptible to drag from the vessel wall, there is a relatively high strength portion with a small loop diameter, and a relatively low strength portion with a large loop diameter is located distally. Withdrawn proximally from the end. Therefore, the entire body region is not easily deformed. Therefore, according to the electrode catheter of claim 2, when the catheter tip is pushed into the blood vessel with the catheter tip as the head, deformation of the catheter tip can be sufficiently suppressed (preserving its shape). it can.

  In addition, since the spiral main body region whose loop diameter increases as it extends in the proximal direction has a shape similar to a drill, it is pushed (screwed) with the catheter tip having such a main body region at the head. Thus, the inside of the blood vessel can be gradually expanded, so that the electrode catheter according to claim 2 can be smoothly pushed into the blood vessel (low resistance).

  According to the electrode catheter according to claim 3, the main body region of the distal end portion of the catheter constituting the electrode catheter has the first loop having a relatively small diameter on the distal side (the base end side of the main body region). Since the second loop having a large diameter is provided on the proximal side (the distal end side of the main body region), it can be smoothly pushed into the blood vessel while maintaining the shape of the catheter distal end portion.

  That is, the main body region of the distal end portion of the catheter constituting the electrode catheter according to claim 3 is positioned on the proximal end side of the first loop having a relatively small diameter (that is, relatively high strength) as the blood vessel wall. The second loop having a relatively large diameter (that is, relatively low strength) located on the distal side of the main body region is less likely to receive drag from the vessel wall. Since it is provided on the proximal side, the entire body region is not easily deformed. Therefore, according to the electrode catheter of the third aspect, when the catheter tip is pushed into the blood vessel with the catheter tip as the head, deformation of the catheter tip can be sufficiently suppressed and prevented and the shape thereof can be maintained. .

  In addition, the first loop having a relatively small diameter and high strength is provided on the distal side, and the second loop having a relatively large diameter and low strength is provided on the proximal side. Since the inside of the blood vessel can be gradually expanded by pushing the front end of the catheter having the body region having such a shape as the head, the electrode catheter according to claim 3 can be smoothly (low resistance) inside the blood vessel. Can be pushed in.

  Furthermore, the ring-shaped electrode mounted on the first loop (distal side) and the ring-shaped electrode mounted on the second loop (proximal side) can increase the diameter of the blood vessel along the longitudinal direction of the blood vessel. Potentials at two different locations (inner peripheral portions) can be measured simultaneously.

  For example, in the case where the blood vessel diameter gradually decreases along the pushing direction of the catheter, the potential at the front portion in the pushing direction is measured by the ring-shaped electrode attached to the first loop, and attached to the second loop. It is possible to measure the electric potential at the rear portion in the pushing direction by the ring-shaped electrode.

  According to the electrode catheter of the fourth aspect, the interval between the ring-shaped electrodes arranged in pairs on the outer periphery of the second loop (ring-shaped electrodes constituting the counter electrode) is inevitably narrowed. It is possible to measure the potential at a narrow interval at the site where the two loops are in contact. As a result, for example, it becomes easier to pick up the local potential at the left atrial side of the pulmonary vein where there is a lot of noise potential, and the potential is measured reliably. can do.

  According to the electrode catheter of the fifth aspect, since the spherical tip electrode is attached to the tip of the catheter tip, the potential can be measured in almost all the region of the catheter tip. Moreover, since the tip electrode is spherical, when the inside of the blood vessel is pushed (screwed) with the tip electrode at the head, even if the inner wall of the blood vessel is pressed or scratched by the tip electrode, the risk of damaging the inner blood vessel is extremely low. . Therefore, the electrode catheter can be safely and smoothly advanced toward the target site.

<First Embodiment>
As shown in FIG. 1, the electrode catheter 1 of the present embodiment includes a catheter body 10, a control handle 20, a catheter tip 30, a plurality of ring-shaped electrodes 41, and a spherical tip electrode 42. .

  The catheter body 10 is an elongated tubular structure having one inner hole, and includes a first tube 11 and a second tube 12.

The first tube 11 has certain flexibility (flexibility), incompressibility in the tube axis direction, and torsional rigidity. The rotational torque from the control handle 20 can be transmitted to the catheter tip 30 by the torsional rigidity of the first tube 11.
Although it does not specifically limit as the 1st tube 11, The thing (blade tube) which braided the tube which consists of resin, such as polyurethane, nylon, and PEBAX (polyether block amide) with the stainless steel strand can be mentioned. .
The length of the first tube 11 is, for example, 50 to 200 cm.

  The second tube 12 is a tube constituting the distal end portion of the catheter body 10 and has an inner hole communicating with the inner hole of the first tube 11, and a deflection mechanism (a plate disposed in the inner hole) to be described later. It is bent by a spring.

A non-toxic resin can be used as a constituent material of the second tube 12. The second tube 12 is configured more flexibly than the first tube 11. The means for relatively flexibly configuring the second tube 12 is not particularly limited, and examples thereof include adopting a configuration in which the second tube 12 is not braided.
The length of the second tube 12 is, for example, 3 to 10 cm, and more preferably 4 to 7 cm.

  The outer diameter of the catheter body 10 (the first tube 11 and the second tube 12) is preferably 2.6 mm or less, more preferably 2.4 mm or less, and a suitable example is 2.3 to 2. 4 mm.

  The inner diameter of the catheter body 10 is 1 when the outer diameter is 2.3 to 2.4 mm, for example, from the viewpoint of securing the accommodation space such as a wire and a lead wire and ensuring torsional rigidity (thickness). It is preferably about 5 to 1.7 mm.

The control handle 20 is connected to the proximal end side of the catheter body 10 (first tube 11). In FIG. 1, 21 is a grip and 22 is a knob.
By rotating the control handle 20, the rotational torque is transmitted to the catheter tip 30 via the catheter body 10.

  Further, as shown in FIG. 3, by sliding the knob 22 toward the proximal end side, the second tube 12 is bent by a later-described deflection mechanism, and the catheter distal end portion 30 is deflected accordingly.

  Therefore, by operating the control handle 20 to rotate and further deflect the catheter tip 30, the catheter tip 30 can be guided to the target site.

The catheter distal end portion 30 is configured by forming a third tube 33 connected to the distal end side of the catheter body 10 (second tube 12) into a predetermined shape.
The outer diameter of the 3rd tube 33 which comprises the catheter front-end | tip part 30 shall be 0.95-1.9 mm, for example, shall be 1.7 mm as a suitable example.

The third tube 33 constituting the catheter distal end 30 has an inner hole communicating with the inner hole of the catheter body 10 (second tube 12).
Examples of the constituent material of the third tube 33 include a bio-acceptable resin material such as polyurethane or PEBAX.

  As shown in FIGS. 2, 4, and 5, the catheter tip 30 includes a straight proximal region 31 that extends in the distal direction and reaches the distal end 30 </ b> D, and a proximal side from the distal end 30 </ b> D. A spiral main body region 32 extending in the proximal direction while forming two loops (first loop 321 and second loop 322) around the region 31, and a tip of the main body region 32 (second loop 322) And a partially spiral tip side region 34 extending in the distal direction. The main body region 32 does not need to extend in the proximal direction at all the parts constituting the main body region 32.

In the present invention, the “distal end” of an electrode catheter refers to a constituent part of the electrode catheter (catheter tip) located at a position in the body that is farthest (far from) the insertion site of the electrode catheter. To do.
The “distal direction” refers to a direction toward the distal end, and the “distal side” refers to a direction relatively closer to the distal end.
The “proximal direction” refers to the direction toward the insertion site of the electrode catheter, and the “proximal side” refers to the direction relatively closer to the insertion site.

In the electrode catheter of the present invention, the tip of the catheter tip (tip of the tip side region) does not coincide with the “distal end” of the electrode catheter.
Consistent with the “distal end” of the electrode catheter of the present invention is the distal end of the proximal end region of the catheter distal end (the proximal end of the body region).
The tip side region of the catheter tip extends in the distal direction from the tip of the body region, but the tip does not reach the distal end.
That is, the distal end of the distal end region is located more distal than the distal end of the main body region, but is more proximal than the distal end of the proximal end region that is the distal end (the proximal end of the main body region).

The body region 32 of the catheter tip 30 has a spiral shape (helical shape) extending in the proximal direction from the distal end 30D, and the tip of the body region 32 is located on the proximal side of the distal end 30D. (Retracted proximally from the distal end 30D).
The main body region 32 includes a first connection portion 323, a first loop 321, a second connection portion 324, and a second loop 322.

  The first loop 321 on the distal side (the proximal side of the main body region 32) has a generally circular shape (strictly in the proximal direction) formed to pivot about the proximal region 31 as a central axis. The loop (slightly extending spiral shape) has a diameter (loop diameter) d1 of, for example, 10 to 30 mm, preferably 13 to 18 mm, and preferably 15 mm.

  The second loop 322 on the proximal side (the distal end side of the main body region 32) has a substantially circular shape (strictly speaking, in the proximal direction, slightly formed around the proximal region 31). The diameter (loop diameter) d2 is larger than the diameter d1 of the first loop, for example, 15 to 40 mm, preferably 20 to 30 mm, and a suitable example is 20 mm. It is said.

  The distance p between the first loop 321 and the second loop 322 is, for example, 2 to 15 mm, preferably 4 to 8 mm, and preferably 6 mm.

The first connecting portion 323 that constitutes the main body region 32 is a portion that extends from the distal end 30 </ b> D, which is the tip of the proximal region 31, radially outward of the loop and reaches the proximal end of the first loop 321.
Since the distal end (distal end) of the proximal end region 31 and the proximal end of the first loop 321 are connected via the first connecting portion 323, the proximal end region 31 is used as a central axis. The first loop 321 can be formed so as to turn around, and the shape stability (hardness to be deformed) of the first loop 321 can be improved.

That is, since the proximal end region 31 functions as an axial core that suppresses crushing in the axial direction, the periphery of the proximal end region 31 is not easily deformed.
Further, since the first loop 321 is formed so as to turn around the proximal end region 31, the separation distance between the first loop 321 and the proximal end region 31 (axial core) (the radius of the loop) Is the maximum of the loop and the proximal region in the loop structure of the distal end of the catheter constituting the conventional electrode catheter (a structure in which the proximal region extends from one point on the circumference forming the loop). The distance can be shorter than the separation distance (corresponding to the diameter of the loop). Therefore, deformation of the first loop 321 (loop bending with respect to the proximal end region as shown in FIG. 17 (4)) can be effectively prevented.

The second connecting portion 324 constituting the main body region 32 extends from the distal end of the first loop 321 in the proximal direction while turning around the proximal end region 31 and being separated from the proximal end region 31. This is a portion reaching the base end of the second loop 322.
The second connecting portion 324 extends so as to be separated from the base end side region 31 (the spiral diameter increases) while turning around the base end side region 31 by approximately 90 °. Thereby, the relatively small-diameter first loop 321 and the relatively large-diameter second loop 322 can be connected.

The distal end side region 34 of the catheter distal end portion 30 is connected to the distal end of the second loop 322 constituting the main body region 32.
The distal end region 34 turns (rotates) around the proximal end region 31 from the distal end of the main body region 32 (second loop 322) and approaches the proximal end region 31 (decreasing the spiral diameter). However, it is formed in a partial spiral shape extending in the distal direction.
Here, “partial spiral shape” refers to the shape of a part of the spiral (number of turns <1).
At the angle at which the distal end region 34 pivots around the proximal end region 31 (FIG. 5A), the distal end of the main body region 32 (second loop 322), the proximal end region 31, and the distal end region 34 The angle θ) that can be formed when the tip is connected is, for example, 65 to 80 °.

The tip of the distal region 34 (tip of the electrode catheter 1) is located more distal than the tip of the main body region 32 (second loop 322), but the tip of the proximal region 31 (distal end 30D). It is located more proximally.
Specifically, as shown in FIG. 5B, the tip of the tip side region 34 is located between a plane including the first loop 321 and a plane including the second loop 322.
Here, the separation distance (distance q shown in FIG. 5 (2)) between the distal end of the distal end side region 34 and the plane including the second loop 322 is, for example, 0.25p to 0.5p (p is the first The distance between the first loop 321 and the second loop 322).

  Since the distal end region 34 pivots around the proximal end region 31 and extends in the distal direction “while approaching the proximal end region 31 (decreasing the spiral diameter)”, FIG. As shown, the tip of the tip side region 34 is located inside the circle forming the second loop 322.

As shown in FIGS. 2 and 4, four ring-shaped electrodes 41 are mounted on the outer periphery of the third tube 33 constituting the first loop 321 at approximately 90 ° intervals. Thereby, for example, pacing and potential can be confirmed in the lung side portion of the pulmonary vein.
Of course, the number of ring-shaped electrodes 41 in the first loop 321 is not limited to four.

  FIG. 6 (1) schematically shows the arrangement state of the ring-shaped electrodes 41 in the first loop 321. In addition, what is shown in the figure is a part of the first loop 321, and what is actually a loop is shown linearly.

In the first loop 321, the width W of the ring-shaped electrode 41 is, for example, 0.2 to 2.0 mm, and a preferred example is 0.75 mm.
In the first loop 321, the gap G1 between the adjacent ring-shaped electrodes 41 is, for example, 7.0 to 23.0 mm, and a preferable example is 11.0 mm.

As shown in FIGS. 2 and 4, 16 ring-shaped electrodes 41 are arranged in eight pairs on the outer periphery of the third tube 33 constituting the second loop 322. That is, eight pairs (16 poles) of counter electrodes formed by the ring-shaped electrode 41 are mounted at intervals of approximately 45 °.
Of course, the number of counter electrodes in the second loop 322 is not limited to eight (the number of ring-shaped electrodes 41 is 16).

FIG. 6B schematically shows the arrangement state of the ring-shaped electrode 41 in the second loop 322. Also, what is shown in the figure is a part of the second loop 322, and what is actually a loop is shown linearly.
In the second loop 322, the ring electrode 41 has the same width as that in the first loop 321.

  The ring-shaped electrode 41 in the second loop 322, for example, the electrode 411 and the electrode 412 shown in FIG. 6 (2) can be said to be “disposed in pairs” (constitute a counter electrode). It is essential that the gap G21 between the electrode 411 and the electrode 412 is narrower than the gap G22 between the electrode 411 (electrode 412) and the other electrode 413 (electrode 414) adjacent thereto (G22> G21). is there.

The gap G21 between the ring electrodes 41 constituting the counter electrode is, for example, 0.5 to 4.0 mm, and is preferably 1.0 mm.
Moreover, the space | interval G22 of the ring-shaped electrode which adjoins but does not make a pair shall be 3.0-14.0 mm, for example, and is 5.5 mm as a suitable example.
A preferred example of the ratio of the intervals (G22 / G21) is 5.5.

The counter electrode by the ring-shaped electrode 41 is attached to the outer periphery of the third tube 33 constituting the second loop 322 (the ring-shaped electrodes 41 are arranged in pairs).
And since the space | interval G21 of the ring-shaped electrode 41 which comprises a counter electrode is inevitably narrow, when using the electrode catheter 1 of this embodiment, in the site | part which the 2nd loop 322 contacts, a narrow space | interval ( The potential can be measured at a short distance. As a result, for example, the local potential can be easily picked up at the left atrial side portion of the pulmonary vein where the noise potential is large, and the potential can be measured reliably.

  In the present embodiment, the ring-shaped electrode gap G22 (counter electrode gap) in the second loop 322 is narrower than the ring-shaped electrode 41 gap G1 in the first loop 321 (G1> G22). ing.

  The ring-shaped electrode 41 attached to the first loop 321 and the second loop 322 is made of a conductive material such as platinum, gold, iridium, or an alloy thereof. The method of attaching the ring electrode 41 is not particularly limited. In addition to a method of fixing a metal material molded into a ring shape to the third tube 33 with an adhesive, a sputtering method, an ion beam evaporation method, or the like. A method of forming a ring electrode by film formation can be mentioned.

A spherical tip electrode 42 is attached to the distal end of the distal end region 34 (the distal end of the catheter distal end portion 30).
Since the tip electrode 42 is attached, the tip electrode 42 is attached from almost the entire region of the catheter distal end portion 30, that is, from the ring-shaped electrode 41 attached to the most proximal side of the first loop 321. A region reaching the tip of the tip side region 34 can be used as a potential measurement region.
In addition, since the tip electrode 42 is spherical, even if the tip electrode 42 presses or scrapes the inner wall of the blood vessel, the blood vessel is not damaged.

The diameter (D) of the spherical tip electrode 42 is preferably 1.0 to 2.0 mm, and particularly preferably 1.8 mm.
In addition, the diameter (D) of the tip electrode 42 needs to be larger than the outer diameter (d) of the catheter tip 30, specifically, 1.05 of the outer diameter (d) of the catheter tip 30. It is preferable that it is more than 1 time, and more preferably 1.05 to 2.5 times.
When the ratio (D / d) is 1.05 or more, the distal end surface of the catheter distal end portion 30 is sufficiently covered by the tip electrode 42, and the damage preventing effect is reliably ensured.

According to the electrode catheter 1 of this embodiment, when the catheter tip 30 is pushed into the blood vessel with the catheter tip 30 at the head, deformation of the catheter tip 30 can be sufficiently suppressed and prevented.
In general, when the catheter is pushed into the blood vessel with the catheter tip as the head, the portion that is most susceptible to drag from the blood vessel wall is the portion located at the distal end of the catheter.
On the other hand, the main body region of the distal end portion of the catheter is not easily deformed in the vicinity of the proximal end, and is more likely to be deformed as it approaches the distal end. Further, the loop of the main body region at the distal end portion of the catheter is more easily deformed as the diameter (loop diameter) increases.

Thus, in the electrode catheter 1 of the present embodiment, the main body region 32 of the catheter distal end portion 30 includes the first loop 321 that is located on the proximal end side and has a relatively small diameter (relatively high strength). A second loop 322 having a relatively large diameter (relatively low strength) located on the distal end side of the main body region 32 is provided on the proximal side.
As described above, the first loop 321 having a relatively high strength is provided on the distal side that is susceptible to a drag from the vessel wall, and the second loop 322 having a relatively low strength is received from the vessel wall. By having it on the hard proximal side, the entire body region 32 is not easily deformed.

  Further, since the proximal end region 31 of the catheter distal end portion 30 acts as the central axis of the first loop 321 and the second loop 322, the shape stability (hardness to be deformed) of these loops is reliably improved. Can be made.

As a result, for example, as shown in FIG. 5 (1), the first loop 321 located on the distal side acts on the drag P1 (any direction on the plane including the first loop 321) from the blood vessel wall. The first loop 321 having a relatively high strength (not easily deformed) does not easily open even when subjected to a drag force.
Further, as shown in FIG. 5 (2), the first loop 321 located on the distal side receives a drag force P2 (a drag force acting in a direction perpendicular to the plane including the first loop 321) from the blood vessel wall. Even so, the first loop 321 having a relatively high strength (not easily deformed) does not easily open. On the other hand, since the second loop 322 having a relatively low strength (easily deformed) is located on the proximal side, it is difficult to receive a drag from the blood vessel wall and can be easily opened even in a low strength loop. There is no.
Furthermore, as shown in FIG. 5 (1), the distal end of the distal end side region 34 (the distal end of the catheter distal end portion 30) is located inside the circle forming the second loop 322. Unlike the catheter tip portion (catheter tip portion 90 shown in FIG. 15) constituting the electrode catheter described, the tip of the tip side region does not make point contact with the blood vessel wall to open the loop.

  Moreover, the main body region 32 of the catheter tip 30 has a first loop 321 having a relatively small diameter and high strength on the distal side, and a second loop having a relatively large diameter and low strength. Since it is provided on the proximal side, the inside of the blood vessel can be gradually expanded by pushing the catheter tip 30 having the body region 32 having such a shape as the head. Therefore, the electrode catheter 1 of this embodiment can be pushed smoothly (low resistance) into the blood vessel.

  Furthermore, the first loop 321 on the distal side and the second loop 322 on the proximal side allow the potentials at two locations (inner peripheral portions) having different blood vessel diameters along the longitudinal direction of the blood vessel to be generated. It can be measured simultaneously.

  For example, in the case where the blood vessel diameter gradually decreases along the pushing direction of the catheter, the potential at the front portion in the pushing direction is measured by the ring-shaped electrode attached to the first loop 321, and the second loop 322 is measured. It is possible to measure the electric potential at the rear portion in the pushing direction by the ring-shaped electrode (counter electrode) attached to the.

Specifically, as schematically shown in FIG. 7, the electrode catheter 1 of the present embodiment is pushed into the pulmonary vein from the left atrium (LA) of the heart with the distal end 30D of the catheter tip 30 at the head. Thus, the first loop 321 can be securely fitted to the tube wall of the lung side portion (PV1) of the pulmonary vein, and the second loop 322 can be attached to the tube wall of the left atrial side portion (PV2) of the pulmonary vein. It can be surely fitted.
As a result, the potential at the pulmonary vein lung side portion (PV1) can be measured by the ring-shaped electrode mounted on the first loop 321 and at the same time, the ring-shaped electrode (mounted on the second loop 322 ( The potential at the left atrial site (PV2) of the pulmonary vein can be measured by the counter electrode).

According to the electrode catheter 1 of this embodiment, the first loop 321 having a relatively small diameter functions as a guide when the catheter tip 30 constituting the catheter is guided to the pulmonary vein. It can be easily placed in a blood vessel.
In addition, as shown in FIG. 7, since the three-dimensional positioning can be performed at the two locations of the first loop 321 and the second loop 322, the loop can be prevented from being inclined or misaligned.
Therefore, according to the electrode catheter 1 of the present embodiment, the placement of the catheter tip 30 in the pulmonary vein can be performed quickly and easily, and stable positioning is also performed at the same time, so the procedure itself can be completed quickly. The burden on the subject can be reduced.
Furthermore, in the second loop 322, a plurality of counter electrodes made of the ring-shaped electrodes 41 adjacent to each other with a narrow gap G21 are arranged via the gap G22. Makes it difficult to pick up noise (for example, current from inside the heart) and enables stable measurement.

  According to the electrode catheter 1 of the present embodiment, the catheter distal end portion 30 constituting the electrode catheter 1 has a straight proximal end region 31 extending in the distal direction to reach the distal end 30D, and the distal end to the proximal end. A helical body region 32 (first coupling portion 323, first loop 321, second coupling portion 324 and second loop 322) extending proximally while forming a loop around the side region 31, and a body The distal end region 34 extending in the distal direction from the distal end of the region 32, so that when the electrode catheter 1 is inserted into the lumen of the sheath and inserted into the blood vessel, the inner portion of the sheath The catheter distal end 30 that is linearly extended in the cavity can be reliably restored to the shape before insertion (the shape shown in FIG. 2) after being pushed out from the distal end opening of the sheath.

FIG. 8 shows a state in which the catheter tip 30 constituting the electrode catheter 1 is pushed out from the tip opening of the sheath S. In addition, illustration of a ring-shaped electrode is abbreviate | omitted in FIG.
The catheter tip 30 includes a distal spiral portion 34 extending in the distal direction, a helical body region 32 extending in the proximal direction (second loop 322, second connecting portion 324, first loop 321, The first connecting portion 323) and the straight proximal end region 31 extending in the distal direction are pushed out from the distal end opening of the sheath S in this order.

As shown in FIGS. 8A and 8B, when the main body region 32 (second loop 322) is pushed out from the tip opening of the sheath S, the tip side region 34 pushed out in advance is the sheath. The main body region 32 wound around S and pushed out following the distal end side region 34 swirls around the sheath S.
Thereafter, when the proximal region 31 is pushed out following the main body region 32 (first connecting portion 323), as shown in FIG. 8 (3), the catheter tip 30 having the shape before insertion, that is, the distal portion A linear proximal region 31 extending in the direction (extrusion direction) to the distal end 30D, and a loop (first loop 321 and second loop 322) around the proximal region 31 from the distal end 30D. And a helical main body region 32 extending in the proximal direction (opposite to the extrusion direction) and a partial helical tip side region 34 extending in the distal direction (extrusion direction) from the front end of the main body region 32. The catheter tip 30 having it is restored.

FIG. 9 shows an example of a state in which the catheter distal end portion that does not have the distal end region is pushed out from the distal end opening of the sheath S. In addition, illustration of a ring-shaped electrode is abbreviate | omitted in FIG.
As shown in FIGS. 9 (1) and (2), when the main body region 32 (second loop 322) is pushed out from the distal end opening of the sheath S at the distal end portion of the catheter that does not have the distal end region. The distal end portion of the main body region 32 (second loop 322) may not wrap around the sheath S. In such a case, the main body region 32 to be pushed out cannot be swung around the sheath S. In this case, as shown in FIG. 9 (3), loops (the first loop 321 and the second loop 322) of the main body region 32 are formed around the proximal side region 31 that is pushed out following the main body region 32. Since the proximal end region 31 is located outside the loop of the main body region 32 at the distal end of the catheter after being pushed out, the shape before insertion cannot be restored.

  As shown in FIGS. 10 and 11, the electrode catheter 1 of this embodiment includes a deflection mechanism for deflecting the catheter tip 30. This deflection mechanism has a pull wire 51 and a leaf spring 52. In addition, in FIG. 10, the catheter front-end | tip part 30 is shown linearly.

  The pull wire 51 constituting the deflection mechanism extends into the inner hole of the catheter body 10. The proximal end portion 51 </ b> B of the pull wire 51 is fixed inside the control handle 20. The control handle 20 is provided with a piston mechanism (not shown) that moves (pulls) the pull wire 51 to the base end side by sliding the knob 22 from the state shown in FIG. 10 to the base end side. On the other hand, the distal end portion 51 </ b> A of the pull wire 51 is fixed to the distal end portion of the leaf spring 52.

  Examples of the constituent material of the pull wire 51 include stainless steel and Ni—Ti alloy. The surface of the pull wire 51 is preferably covered with PTFE “Teflon (registered trademark)” or the like. The diameter of the pull wire 51 is, for example, 0.1 to 0.5 mm.

The base end of the leaf spring 52 constituting the deflection mechanism is fixed to the tip of the first coil tube 53.
The first coil tube 53 is formed by winding a wire having a flat or circular cross section into a coil shape, and extends into the inner hole of the first tube 11 to prevent the first tube 11 from being crushed. It functions as a material. The proximal end of the first coil tube 53 is fixed inside the control handle 20. The proximal end of the catheter body 10 (first tube 11) is fixed with respect to the control handle 20.

A part of the pull wire 51 (range from the tip of the first coil tube 53 to the tip of the leaf spring 52) is surrounded by the second coil tube 54.
The base end of the second coil tube 54 is fixed to the tip of the first coil tube 53, and the tip thereof is slightly based on the tip of the leaf spring 52 (the fixing position of the tip 51A of the pull wire 51). It is fixed to the end side.

The inner diameter of the second coil tube 54 is slightly larger than the diameter of the pull wire 51, and the pull wire 51 can move (slide) in the second coil tube 54.
The second coil tube 54 is preferably made of a metal material such as stainless steel, and its outer surface is preferably covered with a non-conductive member.

A distal end portion 51A of the pull wire 51 is fixed to the distal end portion of the leaf spring 52, and a proximal end portion of the core wire 55 having shape memory characteristics is further fixed to the distal end side thereof. The core wire 55 extends along the inner hole of the third tube 33, and the tip thereof is fixed to the chip electrode 42 as shown in FIG. 11.
The core wire 55 stores the shape (straight and spiral) of the catheter tip 30 and is deformed by applying force (for example, all parts are deformed linearly). Return to shape.
An example of the constituent material of the core wire 55 is a Ni-Ti alloy. The ratio of Ni and Ti in the Ni—Ti alloy is preferably 54:46 to 57:43. Nitinol can be mentioned as a preferred Ni-Ti alloy.

  The deflection mechanism of the catheter tip 30 operates as follows. That is, when the operator slides the knob 22 of the control handle 20 to the proximal end side, the pulling wire 51 is moved to the proximal end side by a piston mechanism (not shown) in the control handle 20, thereby causing the pulling wire 51 at the distal end thereof. The leaf spring 52 to which the distal end portion 51A is fixed is bent, and the distal end portion (second tube 12) of the catheter body 10 including the leaf spring 52 is bent. As a result, the catheter distal end portion 30 is deflected. . When the knob 22 is slid toward the distal end and returned to the original position, the leaf spring 52 becomes linear and the catheter distal end 30 returns to the original orientation. Of course, the deflection mechanism in the electrode catheter of the present invention is not limited to this.

  Lead wires 61 are connected to the plurality of ring-shaped electrodes 41 and the chip electrodes 42, respectively. Each of the lead wires 61 connected to the ring-shaped electrode 41 enters the inner hole of the third tube 33 from the pore formed in the tube wall of the third tube 33, and the inner hole of the third tube 33. , Extending along the inner hole of the second tube 12, the inner hole of the first tube 11, and the inner hole (not shown) of the control handle 20. It is electrically connected to a connector 62 provided at the end.

  The lead wire 61 is disposed so as to be somewhat movable in the inner hole of the catheter body 10 (the second tube 12 and the first tube 11), so that even if the catheter tip 30 is deflected, the lead wire 61 is broken. There is nothing.

  The electrode catheter 1 is connected to the electrocardiograph via a cable connected to the connector 62, and the electric potential measured by the electrode catheter 1 is displayed on the monitor of the electrocardiograph.

<Second Embodiment>
FIG. 12 (1) is an explanatory view schematically showing the shape of the distal end portion of the electrode catheter of the second embodiment of the present invention, and FIG. 12 (2) is a view taken along the line BB in FIG. 12 (1). FIG.
In the electrode catheter of the present embodiment, the catheter body, the control handle, the ring electrode, and the spherical tip electrode are the same as those constituting the electrode catheter 1 of the first embodiment.

  As shown in FIG. 12, the catheter distal end portion 70 constituting the electrode catheter of the present embodiment includes a linear proximal side region 71 extending in the distal direction and reaching the distal end 70D, and a distal end 70D. A helical body region 72 extending proximally while forming two loops (first loop 721, second loop 722) around the proximal region 71, and a body region 72 (second loop 722) ) And a tip-side region 74 having a partial spiral shape extending in the distal direction from the tip.

  The body region 72 of the catheter tip 70 has a spiral shape (helical shape) extending in the proximal direction from the distal end 70 </ b> D, and includes a first connection portion 723, a first loop 721, and a second connection portion 724. , And a second loop 722.

  The first loop 721 on the distal side (the proximal side of the body region 72) is formed in a generally circular shape (strictly in the proximal direction) formed to pivot about the proximal region 71 as a central axis. The loop (slightly extending spiral shape) has a diameter (loop diameter) d3 of, for example, 10 to 40 mm, and preferably 15 to 25 mm.

  The second loop 722 on the proximal side (the distal end side of the main body region 72) has a substantially circular shape (strictly speaking, in the proximal direction, slightly formed around the proximal region 71). The loop has a diameter (loop diameter) that is substantially the same as the diameter d3 of the first loop.

  The separation distance between the first loop 721 and the second loop 722 is, for example, 2 to 15 mm, and preferably 4 to 8 mm.

The first connecting portion 723 constituting the main body region 72 is a portion extending from the distal end 70 </ b> D, which is the tip of the proximal region 71, radially outward of the loop to reach the proximal end of the first loop 721.
Since the distal end (distal end) of the proximal end region 71 and the proximal end of the first loop 721 are connected via the first connecting portion 723, the proximal end region 71 is used as a central axis. The first loop 721 can be formed to turn around, and the shape stability of the first loop 721 can be improved.

  The second connecting portion 724 constituting the main body region 72 extends proximally from the distal end of the first loop 721 while pivoting about the proximal end region 71 by approximately 90 °, so that the base of the second loop 722 is formed. It is the part that reaches the end.

  A plurality of ring electrodes (not shown) are attached to the first loop 721 and the second loop 722, respectively, at regular intervals. The number of ring-shaped electrodes is not particularly limited, but is preferably 1-20 for each loop, and more preferably 4-16. A spherical tip electrode (not shown) is attached to the tip of the second loop 722.

The distal end region 74 of the catheter distal end portion 70 is connected to the distal end of the second loop 722 that constitutes the main body region 72, and around the proximal end region 71 from the distal end of the main body region 72 (second loop 722). It is formed in a partial spiral shape that rotates (rotates) and extends in the distal direction while approaching the proximal end region 71 (decreasing the spiral diameter).
The distal end of the distal region 74 (distal end of the electrode catheter) is located more distal than the distal end of the main body region 72 (second loop 722), but from the distal end of the proximal region 71 (distal end 70D). Is also located on the proximal side. Specifically, as shown in FIG. 12 (2), the distal end of the distal end side region 74 is located between a plane including the first loop 721 and a plane including the second loop 722.
Further, since the distal end region 74 turns around the proximal end region 71 and extends in the distal direction “while approaching the proximal end region 71 (decreasing the spiral diameter)”, FIG. As shown in 1), the distal end of the distal end side region 74 is located inside the circle forming the second loop 722.

  According to the electrode catheter of this embodiment, when the catheter tip 70 is pushed into the blood vessel with the catheter tip 70 at the head, deformation of the catheter tip 70 can be sufficiently suppressed and prevented.

  That is, the main body region 72 of the catheter distal end portion 70 in the electrode catheter of the present embodiment has the first loop 721 located on the proximal end side and having a relatively high strength on the distal side. A second loop 722 located on the distal end side and having a relatively low strength is provided on the proximal side.

  As described above, the first loop 721 having a relatively high strength is provided on the distal side, which is susceptible to a drag from the vessel wall, and the second loop 722 having a relatively low strength is received from the vessel wall. By having it on the hard proximal side, the entire body region 72 is not easily deformed.

  In addition, since the proximal end region 71 of the catheter distal end portion 70 acts as the central axis of the first loop 721 and the second loop 722, the shape stability (hardness to be deformed) of these loops is further improved. be able to.

  Further, the ring-shaped electrode mounted on the first loop 721 and the ring-shaped electrode mounted on the second loop 722 simultaneously cause potentials at two locations (inner peripheral portions) along the longitudinal direction of the blood vessel. Can be measured.

That is, the potential at the front part in the pressing direction is measured by the ring-shaped electrode attached to the first loop 721, and the potential at the rear part in the pressing direction is measured by the ring-shaped electrode attached to the second loop 722. Can do.
For example, as schematically shown in FIG. 13, in a blood vessel BV having a circumferentially cauterized site BV1, the first loop 721 and the second loop 722 are arranged so as to straddle the cauterized site BV1. Then, the potential of the non-cauterized part can be measured by bringing the ring-shaped electrode attached to each of the first loop 721 and the second loop 722 into contact with the non-cauterized part.
By measuring the potential across the ablation site, the effect of ablation can be confirmed. That is, if the lesion site is sufficiently cauterized, a normal potential can be measured. Conversely, when an abnormal potential is measured, it can be inferred that the cauterization condition was weak (cauterization was insufficient).

  According to the electrode catheter of the present embodiment, the catheter distal end portion 70 that constitutes the electrode catheter has a straight proximal end region 71 extending in the distal direction and reaching the distal end 70D, and the proximal end side from the distal end 70D. A helical body region 72 (first coupling portion 723, first loop 721, second coupling portion 724 and second loop 722) extending proximally while forming a loop around region 71, and a body region And a distal spiral region 74 extending in the distal direction from the distal end of 72, so that when the electrode catheter is inserted into the lumen of the sheath and inserted into the blood vessel, the lumen of the sheath The catheter distal end portion 70 in a linearly extending state can be reliably restored to the shape before insertion after being pushed out from the distal end opening of the sheath.

As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible.
For example, the number of loops constituting the main body region of the catheter tip is not limited to two or three, but may be four or more, or may be one (one round). .
Further, the tip electrode attached to the tip of the catheter tip (main body region) may not be spherical. Furthermore, the tip electrode itself may not be attached to the tip of the catheter tip.
The electrode catheter of the present invention can be suitably used for diagnosis of heart disease, but is not limited to this, and is also used for treatment of heart disease, for example, when cauterizing an abnormally electrically active site. Can do.

It is a perspective view which shows 1st Embodiment of the electrode catheter of this invention. FIG. 2 is a partially enlarged perspective view of FIG. 1. FIG. 2 is a perspective view showing a state where a catheter tip portion of the electrode catheter shown in FIG. 1 is deflected (about 180 °). FIG. 4 is a partially enlarged perspective view of FIG. 3. (1) is explanatory drawing which shows typically the shape of the catheter front-end | tip part of the electrode catheter shown in FIG. 1, (2) is an AA arrow line view of (1). (1) is explanatory drawing which shows typically the arrangement state of the ring-shaped electrode in a 1st loop, (2) is explanatory drawing which shows typically the arrangement state of the ring-shaped electrode in a 2nd loop. It is explanatory drawing which shows the state in which the catheter front-end | tip part shown in FIG. 5 is inserted in the pulmonary vein. It is a perspective view which shows the state by which the catheter front-end | tip part which comprises the electrode catheter which concerns on 1st Embodiment is extruded from the front-end | tip opening of a sheath. It is a perspective view which shows the state by which the catheter front-end | tip part which does not have a front end side area | region is pushed out from the front-end | tip opening of a sheath. It is sectional drawing which shows typically the internal structure of the electrode catheter shown in FIG. It is a partial expanded sectional view of FIG. (1) is explanatory drawing which shows typically the shape of the catheter front-end | tip part in 2nd Embodiment of the electrode catheter of this invention, (2) is a BB arrow line view of (1). It is explanatory drawing which shows the state in which the catheter front-end | tip part shown in FIG. 12 is inserted in the blood vessel. It is a perspective view which shows the catheter front-end | tip part of the electrode catheter which concerns on patent document 1. FIG. (1) is a perspective view schematically showing the shape of the catheter tip of the electrode catheter according to Patent Document 1, (2) is an explanatory view when the catheter tip is viewed from the direction of arrow D in (1), (3) is an EE arrow view of (2). It is explanatory drawing which shows typically the state which the catheter front-end | tip part of the electrode catheter which concerns on patent document 1 deform | transforms. It is explanatory drawing which shows typically the state which the catheter front-end | tip part of the electrode catheter which concerns on patent document 1 deform | transforms.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode catheter 10 Catheter main body 11 1st tube 12 2nd tube 20 Control handle 21 Grip 22 Knob 30 Catheter front-end | tip part 33 3rd tube 31 Base end side area | region 32 Main body area | region 321 1st loop 322 2nd loop 323 First connection portion 324 Second connection portion 34 Tip side region 41 Ring electrode 42 Tip electrode 51 Tension wire 52 Leaf spring 53 First coil tube 54 Second coil tube 55 Core wire 61 Lead wire 62 Connector 70 Catheter tip 71 Base end region 72 Main body region 721 First loop 722 Second loop 723 First connection portion 724 Second connection portion 74 Tip end region

Claims (5)

A catheter body having at least one inner hole, a control handle connected to the proximal end side of the catheter body, and an inner hole connected to the distal end side of the catheter body and communicating with at least one of the inner holes of the catheter body An electrode catheter comprising a catheter tip having a plurality of ring-shaped electrodes attached to the outer periphery of the catheter tip,
The catheter tip includes a linear proximal region extending distally to the distal end;
A helical body region extending proximally from the distal end while forming a loop around the proximal region;
A distal region extending distally from the distal end of the body region ,
An electrode catheter, wherein a distal end of the distal end region, which is a free end, is located proximal to a distal end of the proximal region, which is a distal end of the catheter.   2. The electrode catheter according to claim 1, wherein the main body region of the distal end portion of the catheter is formed so that a loop diameter increases as it extends in a proximal direction. A body region of the catheter tip includes a generally circular first loop formed around the proximal region;
A generally circular second loop formed around the proximal region, proximal to the first loop;
The electrode catheter according to claim 1, wherein the diameter of the second loop is larger than the diameter of the first loop.   The electrode catheter according to claim 3, wherein the ring-shaped electrodes attached to the outer periphery of the second loop are arranged in a plurality of pairs.   The electrode catheter according to any one of claims 1 to 4, wherein a spherical tip electrode is attached to a distal end of the catheter distal end portion.

Images