JP5126294B2 - Ablation catheter - Google Patents

Description

  The present invention relates to an ablation catheter used for the treatment of arrhythmia.

Tachycardia arrhythmias occur for sites are present with extra reentry circuit and abnormal motility is sometimes also possible to suppress these abnormal electrical activity in the type of drugs that antiarrhythmic drugs but, Since the abnormal site itself is not removed, instead of the fundamental treatment, instead of the treatment method using the drug, the abnormal tissue is burned down to a small size, that is, ablation treatment that is electrocautery is performed. Yes.

  In ablation treatment, a dedicated catheter (ablation catheter) is inserted mainly through a thick blood vessel (femoral vein or femoral artery) at the base of the foot, and an electrode for measuring an electrocardiogram is attached to the tip of the catheter. Create an ECG while touching the inner wall. By this measurement, an operation (mapping) is performed to determine whether the region is an abnormal part such as a sub-conduction path, and when the abnormal part is found by this mapping operation, the abnormal part is determined as a target by a high frequency (RF wave) from the electrode. Treatment to ablate the tissue site (location that causes tachycardia).

  However, in general, ablation catheters currently used are not easy to control the ablation area and the ablation depth of the ablation site. This control is not only for adjusting the output (energy) of the ablator (high frequency generator), but also for the catheter. Attempts have also been made to increase the cauterization effect by actively cooling the tip electrode. For example, a hole is made in the tip of the electrode, and a saline solution is discharged from there like a sprinkler to cool the tip electrode (an irrigation catheter), or a closed circulatory circuit is installed in the catheter and the electrode is pumped There is a method (cooled tip) in which water is circulated inside and the tip of the electrode is cooled. By adopting these cooling methods, it is possible to reduce the risk of carbonization, steaming and thrombosis of the ablated tissue.

Special table 2005-518864 JP-A-7-184919

Heart View Vol. 3, No. 10, October 1999

However, the known cooling system is complicated in structure and system, and at the same time, the temperature suddenly exceeds the boiling point of 100 ° C. in the deep part of the myocardium, causing a water vapor explosion (usually referred to as a pop phenomenon), and the tissue is ruptured to cause cardiac tamponase. There is also a risk that the phenomenon will occur. In addition, when cauterization is performed using a high-frequency ablation catheter, the local temperature of the living tissue suddenly increases, resulting in carbonization of the tissue, the range of cauterization of the ablation site is small, and the ablation depth Ri also a shallow, can not be sufficiently ablated arrhythmia there is a problem that recurs. Accordingly, an object of the present invention is to provide an ablation catheter that solves the above-described problems.

The present invention provides an ablation catheter having an electrode ( hereinafter also referred to as an ablation electrode) capable of electrocauterizing ( hereinafter also referred to as ablation) biological tissue on the distal end side, and the electrode portion can vibrate and / or rotate at the ablation portion. By providing an ablation catheter characterized in that the above-mentioned problems have been solved.

  That is, the ablation catheter of the present invention is not a conventional cooling system for the electrode used for ablation provided at the distal end thereof, and the electrode is vibrated and / or rotated on the ablation part to provide a gap between the ablation part and the electrode part. By allowing the new blood flow to pass, the tip of the ablation catheter during cauterization can be cooled by the blood flow. That is, by vibrating and / or rotating the electrode on the ablation part, forming a spatial site between the ablation part and the electrode part and / or introducing blood flow between the ablation part and the electrode part, The tip of the electrode is effectively cooled by contact with fresh unheated blood.

  The electrodes of a conventional ablation catheter are cooled by the blood flow in contact with the ablation part except where it contacts the ablation part. Unlike the electrode of the present invention, the electrode of the conventional ablation catheter vibrates and / or moves on the ablation part. Since it does not rotate, the most important electrode cooling effect is reduced by contact with the heated ablation part. On the other hand, the electrode of the ablation catheter of the present invention can introduce an unheated blood flow between the tip of the electrode and the ablation portion by vibrating and / or rotating the electrode. Since the tip is in contact with the unheated bloodstream, the electrode itself can be effectively cooled as described above, and formation of a thrombus or the like can be prevented at the tip. Therefore, in the ablation catheter of the present invention, the electrode itself can be effectively cooled and thrombus formation can be prevented. Therefore, the catheter itself is not provided with a cooling means for the catheter as in the conventional cooling method. However, with a simple structure, it is possible to achieve an extremely excellent effect that it is possible to reduce the risk of carbonization, steaming, thrombosis, and the pop phenomenon of the cauterized tissue. However, the ablation catheter of the present invention may also have a cooling means, such as a conventional ablation catheter.

  The vibration and / or rotation of the electrode of the ablation catheter is not limited as long as the tip of the electrode is in contact with new unheated blood and can form a coolable state. Those whose frequency and / or rotation speed can be controlled are preferable. Such an electrode-equipped catheter is capable of controlling the vibration frequency and / or rotation speed of the electrode based on the detection temperature of the ablation portion detected by the temperature detection means, the width and / or depth of the desired ablation site, etc. In particular, there is one that performs the control automatically. In particular, when the electrode is controlled in consideration of the width of the ablation site, it is preferable that the electrode can be controlled in consideration of the vibration width of the electrode in addition to the control of the vibration frequency and / or the rotation speed. The frequency of the electrode is, for example, 5 to 50 Hz. Further, the vibration and rotation directions of the electrodes may be arbitrary directions, for example, the horizontal direction and / or the vertical direction.

  Control of the electrodes of the ablation catheter is based on the fact that a practitioner such as a doctor confirms the ablation state (for example, by visual confirmation), and in addition to the confirmation, the detection temperature of the ablation part, the width of the desired ablation part And / or a function that can be determined based on depth or the like.

  The vibration and / or rotation of the ablation catheter electrode may be controlled not only by changing the vibration frequency and / or rotation speed but also by ON / OFF control depending on the ablation state. For example, the ablation treatment is started in the OFF state where the vibration of the electrode is not adopted, and the cooling control of the electrode is necessary based on the detection temperature of the ablation part and / or the confirmation state of the ablation part of the practitioner as described above. If it is determined, the vibration of the electrode is turned on and the ablation portion is cooled by starting at an appropriate frequency and / or number of rotations. Based on the cooling result, the frequency and / or rotation of the electrode is again performed. Number control may be performed.

  The means for vibrating and / or rotating the electrode of the ablation catheter is not particularly limited as long as it can vibrate and / or rotate the electrode. For example, an ultrasonic generating means, a micro motor, etc. Can be mentioned.

  According to the present invention, the structure and system are simple, and there is no risk of occurrence of a phenomenon such as causing cardiac tamponase, and there is no carbonization of the tissue due to a rapid increase in local temperature of the living tissue, and the ablation site. We were able to provide an ablation catheter that can easily control the range and depth of ablation.

Is an explanatory diagram tip electrode showed an ablation catheter of the present invention to be rotated.

The structure and system for cooling the ablation electrode can be simplified, and it is possible to provide an ablation catheter with reduced risk of water vapor explosion (pop phenomenon) and carbonization in the myocardium .

DESCRIPTION OF SYMBOLS 1 Ablation catheter 2 Proximal electrode of ablation catheter 3 Tip electrode of ablation catheter 4 Ablation part

Claims (5)

An ablation catheter having an ablation electrode capable of ablating biological tissue, wherein the ablation electrode is capable of vibrating and rotating at an ablation portion. The ablation catheter according to claim 1 , wherein the ablation electrode has a controllable vibration frequency and rotation speed . The ablation catheter according to claim 2 , further comprising a temperature detection means for the ablation portion, wherein the vibration frequency and rotation speed of the ablation electrode can be controlled based on the temperature detected by the temperature detection means. The ablation catheter according to claim 2 or 3 , wherein the ablation electrode can control the vibration width in addition to the vibration frequency and the rotation speed. The ablation catheter according to any one of claims 1 to 4 , wherein the frequency of the electrode is 5 to 50 Hz.

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