WO2013179748A1

WO2013179748A1 - Electrode catheter

Info

Publication number: WO2013179748A1
Application number: PCT/JP2013/058877
Authority: WO
Inventors: 裕生子田中
Original assignee: 日本ライフライン株式会社
Priority date: 2012-05-30
Filing date: 2013-03-26
Publication date: 2013-12-05
Also published as: TWI477299B; CN104363847B; KR101649062B1; CN104363847A; TW201404421A; KR20150023247A; JP2013244382A; JP5348675B1

Abstract

An electrode catheter which has: a catheter shaft (10); and a tip electrode (20) having a spherical portion (21); and is provided with an irrigation mechanism; wherein a plurality of irrigation openings (112) are arranged at a tip reduced-diameter section (10A) of the shaft (10), a plurality of inclined lumens (111) are formed in the interior of the tip reduced-diameter section (10A), and the formula: D₂ ≒ D₁ +2 (L₂·tanα-L₁·tanβ) applies, where (D₁) is the outer diameter of the catheter shaft (10), (D₂) is the diameter of the spherical portion (21), (L₁) is the distance from the rear end of the tip reduced-diameter section (10A) to the tip edge of the irrigation openings (112), (L₂) is the distance from the tip edge of the irrigation openings (112) to a maximum diameter section of the tip electrode (20), (β) is the angle of incline of the tip reduced-diameter section (10A), and (α) is the angle of incline of the inclined lumens (111), the angle of incline (α) being 5.0-12.5° (excluding 9.1-9.3°). According to this electrode catheter, a liquid can be adequately contacted with a tip hemisphere of the tip electrode having the spherical portion.

Description

Electrode catheter

The present invention relates to an electrode catheter, and more particularly to an electrode catheter having an electrode attached to the tip of the catheter and a mechanism for irrigating a liquid such as physiological saline to the electrode.

In the ablation catheter that is an electrode catheter, in order to cool the tip electrode that has become hot during cauterization and to stir and dilute blood around the tip electrode to prevent thrombus formation on the tip electrode surface, Those equipped with an irrigation mechanism are used.

As a conventional catheter provided with an irrigation mechanism, a catheter that injects physiological saline supplied through the catheter shaft into the tip electrode from a plurality of openings formed on the surface of the tip electrode has been introduced. (For example, see Patent Document 1 and Patent Document 2).

Japanese Patent No. 2566281 JP 2006-239414 A

However, conventionally known catheters in which an irrigation opening is formed on the surface of the tip electrode have the following problems (1) to (4).

(1) When an opening is provided on the surface of the tip electrode, an edge is inevitably formed at the opening edge or the like. When cauterization is performed with the tip electrode having such an edge, the current density in the edge portion becomes extremely high, and an abnormal temperature rise occurs in this portion, so that a thrombus may be rapidly formed. .
(2) Even if physiological saline is injected from the opening formed on the surface of the tip electrode, sufficient irrigation cannot be performed on the surface of the tip electrode (the surface is covered with a liquid). The surface cannot be sufficiently cooled, and the formation of thrombus on the surface cannot be sufficiently prevented or suppressed. In particular, in the catheters described in Patent Document 1 and Patent Document 2 that inject physiological saline in a direction perpendicular to the axis of the tip electrode, the saline can be sufficiently brought into contact with the surface of the tip electrode. Therefore, the effect of cooling the electrode surface and the effect of suppressing thrombus formation are extremely low.
(3) By forming a plurality of openings on the electrode surface, it is impossible to ensure a sufficient surface area of the tip electrode, and efficient cauterization treatment cannot be performed.
(4) A temperature sensor such as a thermocouple is usually mounted inside the distal electrode constituting the ablation catheter in order to control the ablation temperature. However, when an opening for irrigation is formed on the surface of the tip electrode (a saline flow path is formed inside the tip electrode), the temperature sensor is excessive due to the saline flowing through the flow path. As a result of the cooling, the temperature of the tissue around the tip electrode cannot be accurately measured and is detected low, and as a result, the ablation temperature may be increased more than necessary.

In order to solve the problems (1) to (4), it is conceivable to irrigate the liquid from the outside (rear end side) with respect to the surface of the tip electrode.
However, when liquid is irrigated from the rear end side with respect to the surface of the tip electrode having a spherical portion, the electrode surface of the spherical portion located on the tip side of the maximum diameter portion of the tip electrode (hereinafter referred to as “tip tip”). The liquid cannot be sufficiently brought into contact with the “hemisphere”.
In addition, when an opening for irrigating liquid on the surface of the tip electrode is formed in the tip surface of the catheter shaft (tip surface perpendicular to the shaft axis), the tip electrode capable of irrigating the liquid is extremely small (for example, When a plurality of openings are arranged on the circumference, the size fits inside the circumference), and efficient ablation treatment cannot be performed by an ablation catheter equipped with such a tip electrode. .
On the other hand, when the irrigation opening is formed on the outer peripheral surface of the catheter shaft, the liquid from the opening is ejected in a direction perpendicular to the shaft axis and cannot be ejected toward the tip electrode.

The present invention has been made based on the above situation.
A first object of the present invention is to provide an electrode catheter capable of irrigating a liquid from the rear end side with respect to the surface of the tip electrode having a spherical portion.
The second object of the present invention is that an abnormal temperature rise (high temperature part) does not occur in a part of the tip electrode during cauterization, and is excellent in the cooling effect of the surface of the tip electrode and the thrombus formation suppressing effect on the surface, And it is providing the electrode catheter provided with the irrigation mechanism which can perform efficient cauterization treatment.
The third object of the present invention is to provide an irrigation mechanism that can sufficiently bring the liquid into contact with the tip hemisphere of the tip electrode having a spherical portion and that is particularly excellent in thrombus formation suppression effect on the tip hemisphere. It is to provide an electrode catheter.
A fourth object of the present invention is to provide an electrode catheter capable of irrigating a liquid also to the tip hemisphere of the tip electrode having a spherical portion having a diameter equal to or larger than the outer diameter of the catheter shaft.
A fifth object of the present invention is to provide an electrode catheter equipped with an irrigation mechanism that can accurately measure the temperature of the tissue around the tip electrode and can appropriately control the ablation temperature. It is in.

(1) The electrode catheter of the present invention includes a catheter shaft having a lumen serving as a liquid flow path,
A tip electrode having a spherical portion connected to the tip side of the catheter shaft;
The catheter shaft has a distal diameter-reduced portion that is tapered in the distal direction, and the distal diameter-reduced portion has a plurality of irrigation openings for irrigating liquid on the surface of the distal electrode. Arranged,
In the inside of the reduced diameter portion of the distal end of the catheter shaft is an electrode catheter in which a plurality of inclined lumens are formed extending in the distal direction while inclining radially outward of the catheter shaft and reaching each of the irrigation openings. And
The outer diameter of the catheter shaft is (D ₁ ), the diameter of the spherical portion of the tip electrode is (D ₂ ), and the axial direction from the rear end of the reduced diameter portion of the catheter shaft to the tip edge of the irrigation opening (L ₁ ), the distance in the axial direction of the shaft from the tip edge of the irrigation opening to the maximum diameter portion of the tip electrode (L ₂ ), and the inclination angle at the tip diameter-reduced portion of the catheter shaft (β ), When the inclination angle of the inclined lumen is (α), the formula (I):
0.95D ₂ ≦ D ₁ +2 (L ₂ tan α−L ₁ tan β) ≦ 1.05 D ₂
Is established, and
The inclination angle (α) is 5.0 to 12.5 ° (excluding 9.1 to 9.3 °).

According to the electrode catheter having such a configuration, a plurality of irrigation openings are arranged in the reduced diameter portion of the catheter shaft, so that the liquid ejected from each of the plurality of irrigation openings is directed in the distal direction. Therefore, the liquid can be ejected from the rear end side with respect to the surface of the tip electrode having a spherical portion.
The liquid sprayed to the tip electrode from each of the plurality of irrigation openings flows in the tip direction along the surface of the tip electrode, so that the surface of the tip electrode is cooled compared to a conventional catheter having an irrigation mechanism. In addition to being excellent in effect, the blood in the vicinity of the surface of the tip electrode is sufficiently agitated and diluted to exert an excellent thrombus formation suppressing effect.

Moreover, since the irrigation opening is formed in the catheter shaft, it is not necessary to form an opening in the tip electrode. As a result, since there is no edge associated with the formation of the opening in the tip electrode, an abnormal temperature rise does not occur in a part of the tip electrode during cauterization, thereby suppressing thrombus formation.
Therefore, the electrode catheter of the present invention is remarkably superior in the thrombus formation suppressing effect on the tip electrode surface as compared with a conventionally known catheter having an irrigation mechanism.
Moreover, since it is not necessary to form an opening in the tip electrode, a sufficient surface area can be secured, and an efficient ablation treatment can be performed as an ablation catheter.

Furthermore, a plurality of inclined lumens are formed inside the distal diameter reduced portion of the catheter shaft, extending in the distal direction while being inclined outward in the radial direction of the catheter shaft and reaching each of the irrigation openings. Since (I) is established and the inclination angle (α) of the inclined lumen is specified, the liquid ejected from the irrigation opening through the inclined lumen is allowed to have a maximum diameter of the tip electrode having a spherical portion. It is possible to reach the vicinity of the electrode surface in the portion, and further, this liquid can be sufficiently brought into contact with the tip hemisphere of the tip electrode (the tip hemisphere can be reliably irrigated).

Moreover, since the above formula (I) is established and the inclination angle (α) of the inclined lumen is specified, the liquid ejected from the irrigation opening through the inclined lumen is allowed to flow outside the catheter shaft. The tip hemisphere of the tip electrode having a spherical portion with a diameter equal to or larger than the diameter can be sufficiently brought into contact.

The “irrigation opening” may be formed across the distal diameter-reduced portion of the catheter shaft and the rear end portion of the distal electrode, and the distal edge of the irrigation opening in such a case is the rear end portion of the distal electrode. Will exist.

(2) In the electrode catheter of the present invention, the inclination angle (α) is preferably 7.0 to 8.0 °, 9.4 to 9.9 °, or 10.5 to 12.0 °.
catheter.

(3) In particular, the inclination angle (α) is preferably 9.4 to 9.9 ° or 10.5 to 12.0 °.

(4) In the electrode catheter of the present invention, the diameter (D ₁ ) of the catheter shaft is 1.0 to 3.0 mm, the distance (L ₁ ) is 1.0 to 3.0 mm, and the distance (L ₂ ) is It is preferable that the angle is 1.0 to 2.5 mm and the inclination angle (β) is 5.0 to 30.0 °.

(5) Moreover, the electrode catheter of the present invention includes a catheter shaft having a lumen serving as a liquid flow path,
A tip electrode having a spherical portion connected to the tip side of the catheter shaft;
The catheter shaft has a distal diameter-reduced portion that is tapered in the distal direction, and the distal diameter-reduced portion has a plurality of irrigation openings for irrigating liquid on the surface of the distal electrode. Arranged,
In the inside of the reduced diameter portion of the distal end of the catheter shaft is an electrode catheter in which a plurality of inclined lumens are formed extending in the distal direction while inclining radially outward of the catheter shaft and reaching each of the irrigation openings. And
The diameter of the spherical portion of the tip electrode is (D ₂ ), the tip diameter-reduced portion at the tip edge of the irrigation opening or the outer diameter of the tip electrode is (D ₃ ), and the tip from the tip edge of the irrigation opening to the tip When the distance in the axial direction of the shaft to the maximum diameter portion of the electrode is (L ₂ ) and the inclination angle of the inclined lumen is (α),
Formula (II): 0.95D ₂ ≦ D ₃ +2 (L ₂ · tan α) ≦ 1.05D ₂
Is established, and
The inclination angle (α) is 5.0 to 12.5 ° (excluding 9.1 to 9.3 °).

According to the electrode catheter having such a configuration, the above formula (II) is established and the inclination angle (α) of the inclined lumen is specified, so that the injection is performed through the inclined lumen from the irrigation opening. The liquid to be reached can reach the vicinity of the electrode surface at the maximum diameter portion of the tip electrode having a spherical portion, and the liquid can be sufficiently brought into contact with the tip hemisphere of the tip electrode (tip hemisphere). The surface can be reliably irrigated).

(6) In the electrode catheter of the present invention, it is preferable that a temperature sensor is attached to the tip side from the irrigation opening, specifically, a temperature sensor is attached to the inside of the tip electrode.

According to the electrode catheter having such a configuration, since the liquid flow path is not formed inside the tip electrode to which the temperature sensor is attached, the temperature sensor is not excessively cooled, and the periphery of the tip electrode Therefore, the temperature of the tissue can be accurately measured, and appropriate control of the ablation temperature can be performed.

According to the electrode catheter of the present invention, the liquid can be irrigated from the rear end side with respect to the entire surface of the tip electrode having a spherical portion.
According to the electrode catheter of the present invention, an abnormal temperature rise does not occur in a part of the tip electrode during cauterization, it is excellent in the effect of cooling the surface of the tip electrode and the effect of suppressing the formation of thrombus on the surface of the tip electrode, Can perform efficient cauterization treatment.
According to the electrode catheter of the present invention, the liquid can be sufficiently brought into contact with the tip hemisphere of the tip electrode having a spherical portion. Therefore, the electrode catheter of the present invention has an effect of inhibiting thrombus formation on the tip hemisphere. Especially good.
According to the electrode catheter of the present invention, it is possible to reliably irrigate the tip hemisphere of the tip electrode having a spherical portion with a diameter equal to or larger than the outer diameter of the catheter shaft.

It is a front view of the ablation catheter which concerns on one Embodiment of the electrode catheter of this invention. FIG. 2 is a transverse sectional view (II-II sectional view of FIG. 1) of a catheter shaft constituting the ablation catheter shown in FIG. FIG. 3 is a longitudinal sectional view showing the inside of the distal end portion of the ablation catheter shown in FIG. FIG. 3 is a longitudinal sectional view showing the inside of the distal end portion of the ablation catheter shown in FIG. It is a longitudinal cross-sectional view which shows the inside of the front-end | tip part of the ablation catheter which concerns on other embodiment of the electrode catheter of this invention.

<First Embodiment>
Hereinafter, an embodiment of an electrode catheter of the present invention will be described with reference to the drawings.
The electrode catheter shown in FIGS. 1 to 4 is an ablation catheter used for treatment of arrhythmia in the heart.

The ablation catheter 100 of this embodiment includes a central lumen 13 through which a lead wire and the like are passed, and 10 sub-lumens (eight serving as a liquid flow path) arranged at equiangular intervals (36 ° intervals) around the central lumen 13. A catheter shaft 10 having two lumens 12) serving as insertion passages for the lumen 11 and the pulling

wires

31, 32, a distal electrode 20 having a spherical portion 21 connected to the distal end side of the catheter shaft 10, and a catheter A ring-shaped electrode 40 attached to the distal end portion of the shaft 10, a control handle 70 connected to the rear end side of the catheter shaft 10, a liquid injection tube 80, and a temperature sensor attached to the inside of the distal end electrode 20 ( Thermocouple) 90, and the catheter shaft 10 has a distal diameter-reduced portion 10 that is tapered toward the distal direction. In this reduced diameter portion 10A, eight irrigation openings 112 for irrigating the liquid on the surface of the distal electrode 20 are arranged, and the rear diameter reduced portion 10A of the catheter shaft 10 has a rear end. An electrode that communicates with each of the eight lumens 11 on the end side, and is formed with eight inclined lumens 111 extending in the distal direction while being inclined radially outward of the catheter shaft 10 to reach each of the irrigation openings 112. The catheter is configured such that the outer diameter of the catheter shaft 10 is (D ₁ ), the diameter of the spherical portion 21 of the distal electrode 20 is (D ₂ ), and the irrigation opening 112 is formed from the rear end of the reduced diameter portion 10 A of the catheter shaft 10. The distance in the axial direction of the shaft to the distal edge (L ₁ ), the distance in the axial direction from the distal edge of the irrigation opening 112 to the maximum diameter portion of the distal electrode 20 (L ₂ ), and the catheter shuffling When the inclination angle at the tip diameter-reduced portion 10A of the rod 10 is (β) and the inclination angle of the inclination lumen 111 is (α), the equation (1): D ₂ = D ₁ +2 (L ₂ · tan α−L ₁ · tan β) is established, and the inclination angle (α) is 5.0 to 12.5 ° (excluding 9.1 to 9.3 °).

3 and 4 show a longitudinal section cut along a plane including the central axes of the central lumen 13 and the two lumens 11 shown in FIG.
Therefore, in FIG. 3 and FIG. 4, two lumens 11 out of “eight lumens 11 serving as liquid flow paths”, two inclined lumens 111 out of “eight inclined lumens 111”, “ Only two irrigation openings 112 of the eight irrigation openings 112 "are shown.

1 is connected to the catheter shaft 10 through the inside of the control handle 70, and the liquid is supplied to the lumen 11 of the catheter shaft 10 through the injection tube 80. Here, as the “liquid”, physiological saline can be exemplified.

The control handle 70 shown in FIG. 1 is connected to the rear end side of the catheter tube 10 and includes a rotating plate 75 for performing a tip deflection operation of the catheter.

As shown in FIG. 2, the catheter shaft 10 constituting the ablation catheter 100 is provided with a central lumen 13 through which a conducting wire (not shown) connected to the tip electrode 20 and the ring electrode 40 is passed, and the central lumen. Ten sub-lumens arranged at equiangular intervals (36 ° = 360 ° / 10) around 13 are formed.

Ten sub-lumens formed at equal intervals around the central lumen 13 have the same outer diameter.

Tensile wires

31 and 32 for performing a tip deflection operation of the catheter are inserted into two lumens 12 of the ten sub-lumens, respectively.
The eight lumens 11 through which the pulling

wires

31 and 32 are not inserted constitute a liquid flow path.

2, the rear ends of the

tension wires

31 and 32 are connected to the rotating plate 75 (see FIG. 1) of the control handle 70, and the distal ends of the

tension wires

31 and 32 are, for example, the distal end portion of the catheter shaft 10. The connection is fixed.
Thereby, for example, when the rotating plate 75 is rotated in the A1 direction shown in FIG. 1, the pulling wire 31 is pulled, and the distal end portion of the ablation catheter 100 is deflected in the arrow A direction and rotated in the B1 direction shown in FIG. When the plate 75 is rotated, the pulling wire 32 is pulled, and the distal end portion of the ablation catheter 100 is deflected in the arrow B direction.

Reference numeral 15 denotes a rigid body embedded in the catheter shaft 10 in order to surely perform the deflection operation by the pulling

wires

31 and 32.
The rigid body 15 is made of a metal bar spring such as a Ni—Ti alloy, and has different bending directions due to the

rigid bodies

15 and 15 arranged in a direction perpendicular to the bending direction (the arrangement direction of the tension wires 31 and 32). The direction can be secured.

The catheter shaft 10 may be made of a material having the same characteristics along the axial direction, but is preferably formed integrally using materials having different rigidity (hardness) along the axial direction. Specifically, it is preferable that the constituent material on the proximal end side has relatively high rigidity, and the constituent material on the distal end side has relatively low rigidity.

The catheter shaft 10 is made of a synthetic resin such as polyolefin, polyamide, polyether polyamide, polyurethane, nylon, or PEBAX (polyether block amide). The proximal end side of the catheter shaft 10 may be a blade tube obtained by braiding a tube made of these synthetic resins with a stainless steel wire.

The outer diameter (D ₁ ) of the catheter shaft 10 (the outer diameter of the portion other than the reduced diameter portion 10A) is preferably 1.0 to 3.0 mm, more preferably 1.3 to 3.0 mm, and particularly preferably. Is 1.6 to 2.7 mm.
The length of the catheter shaft 10 is preferably 600 to 1500 mm, and more preferably 900 to 1200 mm.

As shown in FIGS. 3 and 4, the catheter shaft 10 has a distal diameter-reducing portion 10A that is reduced in diameter toward the distal direction, and an inclined lumen 111 is formed inside the distal-diameter reduced portion 10A. ing.
The inclined lumen 111 communicates with a lumen 11 (non-inclined lumen) that is a liquid flow path on the rear end side, and extends in the distal direction while being inclined outward in the radial direction of the catheter shaft 10, and has a reduced diameter portion 10 </ b> A. It is opened in the outer peripheral surface. This opening is the irrigation opening 112, and eight irrigation openings 112 are formed along the outer periphery of the tip reduced diameter portion 10A.
The rear end of the inclined lumen 111 (the tip of the lumen 11) may be located inside the shaft portion other than the tip reduced diameter portion 10A.

Each of the inclined lumens 111 extends in the distal direction while being inclined outward in the radial direction of the catheter shaft 10. Thereby, the liquid ejected from the irrigation opening 112 through the inclined lumen 111 is ejected toward the distal end side in the axial direction of the catheter shaft 10 and outward in the radial direction. For this reason, it is possible to irrigate the surface of a tip electrode having a certain size (for example, a tip electrode having a spherical portion with a diameter equal to or larger than the outer diameter of the catheter shaft 10).

The distal electrode 20 constituting the ablation catheter 100 has a spherical portion 21, a neck portion 22, and a cylindrical portion 23.
As shown in FIGS. 3 and 4, the distal electrode 20 is connected to the distal end side of the catheter shaft 10 by the cylindrical portion 23 being inserted and fixed inside the distal diameter reduced portion 10 </ b> A.

In this ablation catheter 100, the diameter of the spherical portion 21 corresponding to the maximum diameter of the distal electrode 20 is (D ₂ ), and the distal edge (opening edge) of the irrigation opening 112 from the rear end of the reduced diameter portion 10 A of the catheter shaft 10. (L ₁ ), the distance in the shaft axial direction from the tip edge of the irrigation opening 112 to the maximum diameter portion of the tip electrode 20 (L ₂ ). When the inclination angle of the distal diameter reducing portion 10A of the catheter shaft 10 is (β) and the inclination angle of the inclined lumen 111 is (α),
Formula (1): D ₂ = D ₁ +2 (L ₂ · tan α−L ₁ · tan β) is established.

Here, the outer diameter (the diameter of a circle connecting each of the plurality of tip edges) of the tip reduced diameter portion 10A on the tip edge of the irrigation opening 112 can be represented by D ₁ -2 · L ₁ · tan β.
On the other hand, the liquid ejected in the distal direction from the distal edge of the irrigation opening 112 at the ejection angle equal to the inclination angle (α) of the inclined lumen 111 moves the shaft axis while moving the distance (L ₂ ) in the shaft axis direction. The distance L ₂ · tan α is moved in a direction perpendicular to the direction (radial direction of the shaft).

As a result, when the liquid ejected from the leading edge of the irrigation opening 112 moves a distance (L ₂ ) in the shaft axial direction, the diameter of the imaginary circle connecting the positions where the liquid reaches is D ₁ -2 · L ₁ · tan β + 2 · L ₂ · tan α = D ₁ +2 (L ₂ · tan α−L ₁ · tan β).

Therefore, the diameter (D ₂ ) of the spherical portion 21 corresponding to the maximum diameter of the tip electrode 20 and the diameter of the virtual circle [D ₁ +2 (L ₂ · tan α−L ₁ · tan β)] always matches with the ablation catheter 100, the liquid ejected from the distal edge of the irrigation opening 112 is transferred to the electrode surface at the maximum diameter portion of the distal electrode 20. Can be reached.
In FIG. 4, an extrapolated line EX obtained by extrapolating (extending) an inner straight line that defines the inclined lumen 111 schematically shows a path of liquid ejected from the tip edge of the irrigation opening 112.

In the ablation catheter 100, the distance in the axial direction of the shaft from the rear end of the reduced diameter portion 10A of the catheter shaft 10 to the distal end edge of the irrigation opening 112 (projection distance to the central axis of the catheter shaft 10) (L ₁ ) The thickness is preferably 1.0 to 3.0 mm, more preferably 1.5 to 2.7 mm.
If this distance (L ₁ ) is too small, the above equation (1) cannot be satisfied or the inclination angle of the inclined lumen 111 is increased (12.5) in order to satisfy the above equation (1). The electrode catheter of the present invention cannot be constructed.
On the other hand, when the distance (L ₁ ) is excessive, the distance of the inclined lumen 111 becomes too long, and the processing becomes difficult. Further, since the ring-shaped electrode 40 cannot be provided on the inclined lumen 111, the distance between the ring-shaped electrode 40 and the tip electrode 20 becomes excessive, and it becomes difficult to design in accordance with a request to reduce the distance between these electrodes. Also occurs.

The inclination angle (β) at the distal diameter reduced portion 10A of the catheter shaft 10 is preferably 5.0 to 30.0 °, and more preferably 7.0 to 20.0 °.

When the inclination angle (β) is too small, it is necessary to design the distance (L ₁ ) excessively in order to obtain the inclination angle of the inclined lumen 111, which causes the same problem as described above.
On the other hand, when the inclination angle (β) is excessive, the distance of the inclined lumen 111, particularly the distance to the rear end edge of the irrigation opening 112 (in FIG. 4, the linear distance outside the section defining the inclined lumen 111). ) Becomes smaller, and the guide function of pushing the ejected liquid toward the tip may be impaired. In this case, the liquid to be ejected immediately spreads too much in the outer diameter direction, resulting in excessive diffusion.

−2 · L ₁ · tan β in the above equation (1) corresponds to the amount of reduction in the diameter of the tip reduced diameter portion 10A from the rear end of the tip reduced diameter portion 10A to the tip edge of the irrigation opening 112.
When 2 · L ₁ · tan β is excessive, the diameter of the catheter shaft is excessive, which makes it difficult to design the entire catheter.

The distance in the axial direction of the shaft from the distal end edge of the irrigation opening 112 to the maximum diameter portion of the distal electrode 20 (projection distance to the central axis of the catheter shaft 10) (L ₂ ) is 1.0 to 2.5 mm. The thickness is preferably 1.2 to 2.0 mm.

When this distance (L ₂ ) is too small, it becomes difficult for the liquid ejected from the irrigation opening to be blocked by the rear end portion of the spherical portion and to reach the vicinity of the electrode surface at the maximum diameter portion. .
On the other hand, when this distance (L ₂ ) is excessive, it becomes difficult for the liquid ejected from the irrigation opening to reach the vicinity of the electrode surface at the maximum diameter portion.

In the ablation catheter 100, the inclination angle (α) of the inclined lumen 111 is 5.0 to 12.5 ° (excluding 9.1 to 9.3 °).

In order to perform the effective ablation treatment, the diameter (D ₂ ) of the spherical portion 21 of the tip electrode 20 is established by the above formula (1) and the inclination angle (α) being 5 ° or more. The required size (for example, the ratio of the diameter of the spherical portion 21 to the outer diameter of the catheter shaft 10 (D ₂ / D ₁ ) is 0.7 or more).
When this inclination angle is less than 5 °, the diameter of the spherical portion of the tip electrode becomes too small, and an efficient ablation treatment cannot be performed by an ablation catheter equipped with such a tip electrode.

Further, when the inclination angle (α) is 12.5 ° or less, the liquid ejected from the irrigation opening 112 toward the maximum diameter portion of the tip electrode 20 through the inclination lumen 111 is allowed to flow in the maximum diameter portion. The vicinity of the electrode surface can be reliably reached.
Further, the liquid that is ejected from the irrigation opening 112 through the inclined lumen 111 having an inclination angle (α) of 12.5 ° or less and flows along the shape of the tip electrode 20 is directed to the center of the tip electrode 20. The maximum force due to the stable action of the force (the force caused by the flow velocity difference (pressure difference) between the liquid flowing in the vicinity of the electrode surface and the liquid flowing away from the electrode surface) The liquid that has reached the vicinity of the electrode surface in the diameter portion can then form a flow that covers the tip hemisphere 21A, thereby sufficiently bringing the liquid into contact with the tip hemisphere 21A of the tip electrode. (The tip hemisphere 21A can be reliably irrigated).

When the inclination angle of the inclined lumen is excessive, even the liquid ejected from the irrigation opening 112 toward the maximum diameter portion of the tip electrode 20 is sufficient for the vicinity of the electrode surface at the maximum diameter portion. It becomes impossible to reach the liquid, and even if the liquid reaches the vicinity of the electrode surface at the maximum diameter portion, it becomes easy to diffuse, and it becomes difficult to form a liquid flow that covers the tip hemisphere.
As a result, as shown in Comparative Example 4 to be described later, the liquid cannot be sufficiently brought into contact with the tip hemisphere.

Further, according to the study by the present inventors, an electrode catheter satisfying the above formula (1) and having an inclination angle (α) of the inclination lumen in the range of 5.0 to 12.5 ° is provided. However, it was confirmed that the liquid could not be brought into sufficient contact with the tip hemisphere only when the inclination angle (α) was 9.1 to 9.3 ° (Comparative Example 1 described later). To 3).
Although the reason for this is not clear, the force that tries to direct the liquid flow toward the center direction (inner side) of the tip electrode becomes unstable only in the range of the tilt angle (α) described above. This is presumed to be because it becomes impossible to form a liquid flow that covers the hemisphere.

For the above reasons, the inclination angle (α) of the inclined lumen 111 is usually 5.0 to 9.0 ° or 9.4 to 12.5 °, preferably 7.0 to 8.0 °, It is set to 9.4 to 9.9 ° or 10.5 to 12.0 °, particularly preferably 9.4 to 9.9 ° or 10.5 to 12.0 °.

The diameter (D ₂ ) of the spherical portion 21 corresponding to the maximum diameter of the tip electrode 20 is the outer diameter (D ₁ ) of the catheter shaft 10, the distance (L ₁ ), the distance (L ₂ ), and the inclination angle (β ), Which is determined based on the above-described equation (1) by the inclination angle (α). As the inclination angle (α) of the inclination lumen 111 increases, the diameter (D ₂ ) of the spherical portion 21 also increases.
The diameter (D ₂ ) of the spherical portion 21 determined in this way is preferably 1.0 to 3.0 mm, more preferably 1.5 to 2.5 mm, and particularly preferably 1.7 to 2 mm. .3 mm.

The ratio (D ₂ / D ₁ ) of the diameter (D ₂ ) of the spherical portion 21 of the tip electrode 20 to the outer diameter (D ₁ ) of the catheter shaft 10 is preferably 0.5 to 1.5, and more preferably. Is set to 0.7 to 1.0.

When the value of (D ₂ / D ₁ ) is too small (for example, less than 0.5), it is difficult to perform efficient cauterization treatment depending on the catheter provided with such a tip electrode.
On the other hand, when the value of (D ₂ / D ₁ ) is excessive, a sufficient amount of liquid is irrigated onto the surface of such a tip electrode (a sufficient cooling effect and thrombus formation suppressing effect is obtained). It is difficult to express).

As shown in FIGS. 3 and 4, a temperature sensor 90 made of a thermocouple or the like for controlling the ablation temperature is mounted inside the tip electrode 20. Further, the conducting wire 95 connected to the temperature sensor 90 is drawn through the central lumen 13.
When the ablation catheter 100 is used (at the time of ablation treatment), the temperature sensor 90 measures the temperature of the tissue around the tip electrode 20, and this measurement temperature is fed back to control the ablation temperature (adjustment of high-frequency energy). .

According to the ablation catheter 100 of this embodiment, the eight irrigation openings 112 are arranged in the tapered distal diameter-reducing portion 10A, so that the liquid ejected from each of the irrigation openings 112 is directed in the distal direction. Therefore, the liquid can be ejected from the rear end side with respect to the surface of the tip electrode 20.
Then, the liquid ejected from the rear end side (each of the irrigation openings 112 arranged in the distal diameter-reduced portion 10A of the catheter shaft 10) with respect to the distal electrode 20 is the rear end portion (neck portion) of the distal electrode 20 22) from the tip portion (spherical portion 21) toward the tip direction along the surface of the tip electrode 20, and blood around the tip electrode 20 is sufficiently agitated / diluted so that an irrigation mechanism is provided. Compared to a conventional catheter, the effect of cooling the surface of the tip electrode 20 is excellent, and an excellent effect of suppressing thrombus formation is also obtained by sufficiently stirring and diluting the blood near the surface of the tip electrode 20.

In addition, eight inclined lumens 111 extending in the distal direction while being inclined outward in the radial direction of the catheter shaft 10 and reaching each of the irrigation openings 112 are formed inside the reduced diameter portion 10A of the catheter shaft 10. Therefore, the liquid ejected from each of the irrigation openings 112 is ejected toward the outer side in the distal direction (the distal side in the axial direction of the catheter shaft 10 and the outer side in the radial direction). Here, the liquid ejection angle coincides with the inclination angle (α) of the inclined lumen 111.

In addition, eight inclined lumens 111 extending in the distal direction while being inclined outward in the radial direction of the catheter shaft 10 and reaching each of the irrigation openings 112 are formed inside the reduced diameter portion 10A of the catheter shaft 10. And the above formula (1): D ₂ = D ₁ +2 (L ₂ · tan α−L ₁ · tan β) is satisfied, and the inclination angle (α) of the inclination lumen is 5.0 to 12.5 °. (However, except 9.1 to 9.3 °), the liquid ejected from the irrigation opening 112 through the inclined lumen 111 is allowed to flow in the vicinity of the electrode surface at the maximum diameter portion of the tip electrode 20. Furthermore, the liquid can be sufficiently brought into contact with the tip hemispherical surface 21A of the tip electrode 20 (the tip hemispherical surface 21A can be reliably irrigated) (Examples 1 to 5 described later). See 15 .

Further, even if the spherical portion 21 of the tip electrode 20 has a diameter (D ₂ ) equal to or larger than the outer diameter (D ₁ ) of the catheter shaft 10, the liquid ejected from the irrigation opening 112 through the inclined lumen 111. Can reach the vicinity of the electrode surface at the maximum diameter portion of the tip electrode 20, and this liquid can be sufficiently brought into contact with the tip hemispherical surface 21A of the tip electrode 20 (examples described later). 12-15).

In addition, since the irrigation opening 112 is formed in the insulating catheter shaft 10 (tip reduced diameter portion 10A) and the conductive tip electrode 20 has no edge, when the ablation catheter 100 is used (at the time of cauterization). In this case, an abnormal temperature rise (high temperature part) does not occur in a part of the tip electrode 20, and the formation of thrombus formed by contact of blood with such high temperature part is suppressed.

In addition, since it is not necessary to form an irrigation opening in the tip electrode 20, a sufficient surface area can be secured, and an efficient ablation treatment can be performed as an ablation catheter.

In addition, since the temperature sensor 90 is attached to the tip side of the irrigation opening 112, there is no need to form a liquid flow path inside the tip electrode 20 to which the temperature sensor 90 is attached. 90 is not excessively cooled, and the temperature of the tissue around the tip electrode 20 can be accurately measured.

The ablation catheter 100 shown in FIG. 4 satisfies the above formula (1): D ₂ = D ₁ +2 (L ₂ · tan α−L ₁ · tan β). As a result, the value of D ₁ +2 (L ₂ · tan α−L ₁ · tan β) is in the range of 0.95D ₂ to 1.05D ₂ and the inclination angle (α) is 5.0 to 12.5 °. (However, except 9.1 to 9.3 °), the liquid ejected from the irrigation opening through the inclined lumen is sufficiently brought into contact with the tip hemisphere of the tip electrode ( It was confirmed that the tip hemisphere can be reliably irrigated).

When the value of D ₁ +2 (L ₂ · tan α−L ₁ · tan β) is less than 0.95D ₂ , a part of the liquid ejected from the irrigation opening is blocked by the rear end portion of the spherical portion, and the tip electrode It is difficult to bring sufficient liquid into contact with the tip hemisphere.
On the other hand, when the value of D ₁ +2 (L ₂ · tan α−L ₁ · tan β) exceeds 1.05D ₂ , the liquid ejected from the irrigation opening is allowed to flow near the electrode surface at the maximum diameter portion of the tip electrode 20. May not be able to be reached efficiently.

<Second Embodiment>
The ablation catheter 105 shown in FIG. 5 includes a catheter shaft 50 having ten sub-lumens (eight lumens 51 serving as a liquid flow path and two lumens serving as an insertion passage for a tension wire). The catheter shaft 50 has a distal diameter-reducing portion 50A that is tapered toward the distal direction, and the distal diameter-reduced portion 50A has eight irrigation for irrigating the surface of the distal electrode 20. An opening for use 512 is disposed, and the inside of the reduced diameter portion 50A of the catheter shaft 50 communicates with each of eight lumens 51 (non-inclined lumens) on the rear end side, and is inclined outward in the radial direction of the catheter shaft 10. On the other hand, eight inclined lumens 511 extending in the distal direction and reaching each of the irrigation openings 512 are formed.

In FIG. 5, the same reference numerals are used for the same components as those of the ablation catheter 100 shown in FIG.
Further, in FIG. 5, two lumens 51 of “eight lumens 51 serving as a liquid flow path”, two inclined lumens 511 of “eight inclined lumens 511”, “eight irrigation” Two of the irrigation openings 512 "are shown.

In the rear end portion (neck portion 22) of the distal electrode 20 constituting the ablation catheter 105, a liquid guide groove 26 that is continuous with each of the inclined lumens 511 and is inclined at the same angle as the inclination angle (α) of the inclined lumen 511 is provided. Is formed.
Thereby, the irrigation opening 512 is formed across the distal diameter reduced portion 50A of the catheter shaft 50 and the neck portion 22 of the distal electrode 20, and the distal edge of the irrigation opening 512 is It exists in the neck part 22.
By forming the guide groove 26, the spray angle of the liquid sprayed from the tip edge of the irrigation opening 512 located at the neck portion 22 of the tip electrode 20 matches the tilt angle (α) of the tilt lumen 511. Can be made.

In the ablation catheter 105 shown in FIG. 5, the diameter of the spherical portion 21 of the tip electrode 20 is (D ₂ ), the outer diameter of the tip electrode 20 (neck portion 22) at the tip edge of the irrigation opening 512 is (D ₃ ), When the distance in the axial direction of the shaft from the tip edge of the irrigation opening 512 to the maximum diameter portion of the tip electrode 20 is (L ₂ ) and the tilt angle of the tilt lumen 511 is (α), equation (2): D ₂ = D ₃ +2 (L ₂ · tan α) is satisfied, and the inclination angle (α) is 5.0 to 12.5 ° (except for 9.1 to 9.3 °).

According to the ablation catheter 105 of this embodiment, the liquid ejected from the irrigation opening 512 through the inclined lumen 511 can reach the vicinity of the electrode surface at the maximum diameter portion of the tip electrode 20, and The liquid can be sufficiently brought into contact with the tip hemisphere 21A of the tip electrode 20 (the tip hemisphere 21A can be reliably irrigated).

The ablation catheter 105 shown in FIG. 5 satisfies the above formula (2): D ₂ = D ₃ +2 (L ₂ · tan α). As a result of extensive studies by the inventor, D ₃ +2 (L ₂ · tan α) is in the range of 0.95D ₂ to 1.05D ₂ and the inclination angle (α) is 5.0 to 12.5 ° (however, 9.1 to 9.3) By excluding °, the liquid ejected from the irrigation opening through the inclined lumen should be in sufficient contact with the tip hemisphere of the tip electrode (to ensure that the tip hemisphere is irrigated). It was confirmed that

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 inclined lumens formed inside the tip diameter-reduced portion is not limited to 8, and can be appropriately selected within a range of 4 to 12, for example.
Further, by interposing an intermediate member (an intermediate member having a means for joining and / or diverting liquid) between the tip reduced diameter portion and a portion other than the tip reduced diameter portion, the inside of the tip reduced diameter portion The number of the inclined lumens formed on the inner surface may be different from the number of the lumens (lumens serving as a liquid flow path) formed inside the portion other than the tip diameter-reduced portion.
In addition, as a constituent material of the tip portion including the tip reduced diameter portion, a material different from the constituent material of the shaft portion other than the tip portion (for example, an aromatic polyether ketone such as polyether ether ketone (PEEK), a ceramic material, etc. ) May be adopted.

<Example 1>
3 and 4, the catheter shaft 10 has an outer diameter (D ₁ ) of 2.4 mm, the distance (L ₁ ) is 2.63 mm, and the inclination angle of the distal diameter reduced portion 10A. (Β) is 10.0 °, the distance (L ₂ ) is 1.21 mm, the inclination angle (α) of the inclined lumen 111 is 5.0 °, and the diameter of the spherical portion 21 of the tip electrode 20 (D ₂ = For the ablation catheter 100 in which D ₁ +2 (L ₂ · tan α−L ₁ · tan β) is 1.68 mm and (D ₂ / D ₁ ) is 0.70, this distal end portion is immersed in blood. When the physiological saline is irrigated in the state, the presence state of the physiological saline in the liquid (blood and / or physiological saline) in contact with the distal hemispherical surface 21A of the distal electrode 20 is analyzed using the analysis software “SolidWorks Flow Simulation” ( D ssault was simulated by using the Systems SolidWorks Corporation Co., Ltd.).
As a result, the ratio of the electrode surface in contact with the liquid having a physiological saline abundance ratio (saline content ratio in the liquid) of 40% or more (the ratio of the electrode surface in the total area of the tip hemisphere 21A) Is 95 area% or more, and according to the specifications of Example 1, it was confirmed that physiological saline could be sufficiently brought into contact with the tip hemisphere.
Here, the setting parameters in the above analysis software are as follows.

(1) Blood:
・ Viscosity = 7.6 × 10 ⁻³ Pa · s
・ Temperature = 37 ℃ (equivalent to body temperature)
・ Pressure = 100mmHg (equivalent to blood pressure)

(2) Saline ・ Temperature = 25 ° C
・ Injection amount = 5 to 15 cc / min

<Examples 2 to 15 and Comparative Examples 1 to 4>
Ablation catheter similar to that of Example 1 except that the distance (L ₁ ), the distance (L ₂ ), the inclination angle (α) of the inclined lumen, and the diameter (D ₂ ) of the spherical portion were changed according to Table 1 below. In the same manner as in Example 1, the presence of physiological saline in the liquid in contact with the tip hemisphere of the tip electrode was simulated. The results (the ratio of the electrode surface in contact with the liquid having an abundance of physiological saline of 40% or more) are also shown in Table 1 below.

DESCRIPTION OF SYMBOLS 100 Ablation catheter 10 Catheter shaft 10A Tip diameter reducing part 11 Lumen (liquid flow path)
12 lumens (Tension wire insertion path)
13 Central lumen 15 Rigid body (wire)
111 Inclined lumen 112 Irrigation opening 20 Tip electrode 21 Tip bulging portion 22 Neck portion 23 Cylindrical portion 26 Liquid guide groove 31 Tension wire 32 Tension wire 40 Ring electrode 50 Catheter shaft 50A Tip diameter reduction portion 51 Lumen Flow path)
511 Inclined lumen 512 Irrigation opening 70 Control handle 75 Rotating plate 80 Liquid injection tube

Claims

A catheter shaft having a lumen that serves as a liquid flow path;
A tip electrode having a spherical portion connected to the tip side of the catheter shaft;
The catheter shaft has a distal diameter-reduced portion that is tapered in the distal direction, and the distal diameter-reduced portion has a plurality of irrigation openings for irrigating liquid on the surface of the distal electrode. Arranged,
In the inside of the reduced diameter portion of the distal end of the catheter shaft is an electrode catheter in which a plurality of inclined lumens are formed extending in the distal direction while inclining radially outward of the catheter shaft and reaching each of the irrigation openings. And
The outer diameter of the catheter shaft is (D 1 ), the diameter of the spherical portion of the tip electrode is (D 2 ), and the axial direction from the rear end of the reduced diameter portion of the catheter shaft to the tip edge of the irrigation opening (L 1 ), the distance in the axial direction of the shaft from the tip edge of the irrigation opening to the maximum diameter portion of the tip electrode (L 2 ), and the inclination angle at the tip diameter-reduced portion of the catheter shaft (β ), When the inclination angle of the inclined lumen is (α), the formula (I):
0.95D 2 ≦ D 1 +2 (L 2 tan α−L 1 tan β) ≦ 1.05 D 2
Is established, and
An electrode catheter, wherein the inclination angle (α) is 5.0 to 12.5 ° (excluding 9.1 to 9.3 °).
2. The electrode catheter according to claim 1, wherein the inclination angle (α) is 7.0 to 8.0 °, 9.4 to 9.9 °, or 10.5 to 12.0 °.
The electrode catheter according to claim 1, wherein the inclination angle (α) is 9.4 to 9.9 ° or 10.5 to 12.0 °.
The diameter (D 1 ) of the catheter shaft is 1.0 to 3.0 mm,
The distance (L 1 ) is 1.0 to 3.0 mm,
The distance (L 2 ) is 1.0 to 2.5 mm,
The electrode catheter according to any one of claims 1 to 3, wherein the inclination angle (β) is 5.0 to 30.0 °.
A catheter shaft having a lumen that serves as a liquid flow path;
A tip electrode having a spherical portion connected to the tip side of the catheter shaft;
The catheter shaft has a distal diameter-reduced portion that is tapered in the distal direction, and the distal diameter-reduced portion has a plurality of irrigation openings for irrigating liquid on the surface of the distal electrode. Arranged,
In the inside of the reduced diameter portion of the distal end of the catheter shaft is an electrode catheter in which a plurality of inclined lumens are formed extending in the distal direction while inclining radially outward of the catheter shaft and reaching each of the irrigation openings. And
The diameter of the spherical portion of the tip electrode is (D 2 ), the tip diameter-reduced portion at the tip edge of the irrigation opening or the outer diameter of the tip electrode is (D 3 ), and the tip from the tip edge of the irrigation opening to the tip When the distance in the axial direction of the shaft to the maximum diameter portion of the electrode is (L 2 ) and the inclination angle of the inclined lumen is (α),
Formula (II): 0.95D 2 ≦ D 3 +2 (L 2 · tan α) ≦ 1.05D 2
Is established, and
An electrode catheter, wherein the inclination angle (α) is 5.0 to 12.5 ° (excluding 9.1 to 9.3 °).
The electrode catheter according to claim 1 or 5, wherein a temperature sensor is attached to the distal end side of the irrigation opening.