WO2007059361A1

WO2007059361A1 - Endocardial electrophysiology device and method

Info

Publication number: WO2007059361A1
Application number: PCT/US2006/045163
Authority: WO
Inventors: Steve Berhow; Zhenghui Cheng; Gordon Hocking
Original assignee: Access Point Technologies
Priority date: 2005-11-21
Filing date: 2006-11-21
Publication date: 2007-05-24

Abstract

A multiple electrode electrophysiology catheter is provided for use with a therapy catheter to provide post and pre-therapy mapping functionality while avoiding the exchange of a guide wire through the therapy catheter. The device and method improve speed and safety of the ablation process.

Description

ENDOCARDIAL ELECTROPHYSIOLOGY DEVICE AND METHOD

Cross Reference to Related Cases This case claims priority from and the benefit thereof and incorporates entirely: U.S. Provisional Application 60/738,518, filed 11/21/2005, entitled "Endocardial Electrophysiology Device and Method."

Field of the Invention The present invention relates generally to electro physiology

(EP) and more particularly to an EP mapping catheter for use in conjunction with the delivery of ablation therapy.

Background of the Invention Cardiac ablation involves the destruction of conductive tissues within the heart. These conductive tissues typically participate in arrhythmias and the destruction of the conductive tissues provides a cure for the patient. Numerous technologies have been created to destroy or ablate cardiac tissue including laser energy, ultrasonic energy, thermal energy and radio frequency energy. A typical ablation procedure begins with an EP mapping operation where one or more catheters having one or more electrodes are maneuvered around the cardiac chamber or surface attempting to locate areas of spurious electrical conduction. With the location for the delivery of desired ablation therapy located the mapping catheters are typically removed and a separate therapy delivery catheter is positioned at the location. Registration between the mapping and therapy catheter is desirable but difficult to achieve except when the lesion created by the therapy device is large. After a therapy is delivered it is common practice to confirm that the conduction has been interrupted by another mapping operation. This sequence of map-ablate-map results in extremely long procedures times, much of which is accomplished under fluoroscopy. This is undesirable from the standpoint of patient care and physicians are repeatedly exposed to high x-ray dosage, which is also undesirable. It is also important to note that the conventional techniques require multiple insertions and removal of catheters which increases the level of damage to the vessels used to deliver the devices which creates a separate safety issue. It must be recognized that damage to the blood vessels is a substantial risk and smaller number of device exchanges is desirable.

Summary of the Invention In contrast to prior devices and methods the present invention includes a novel EP catheter that can be used with a conventional therapy delivery catheter. The mapping catheter itself may be used independently but it is preferred to combine its use with the therapy catheter to create a system. The system permits a method to be carried out which greatly reduces the amount of time required for an ablation procedure.

In operation a therapy catheter with an access lumen that may be used as a guidewire lumen, is provided for creating a lesion. A low profile, flexible multiple electrode EP catheter may be delivered through this guidewire lumen to provide pre and post ablation mapping. The lumen and therapy device allows the catheter to be quickly and rapidly positioned proximate the area of ablation. In an alternate embodiment the EP catheter can carry a distal electrode to deliver ablation energy.

Brief Description of the Drawings

In the several figures of the Drawings like reference numerals indicate identical structure wherein:

Fig. 1 is a view of the EP catheter; Fig. 2 is a cross section of the catheter of Fig. 1;

Fig. 3 is a cross section of the catheter of Fig. 1; Fig. 4 is a view of an anatomic structure; Fig. 5 is a view of a step in a method of using the invention; Fig. 6 is a view of a step in a method of using the invention; Fig. 7 is a view of a step in a method of using the invention; Fig. 8 is a view of a step in a method of using the invention; Fig. 9 is a view of a step in a method of using the invention; Fig. 10 is a view in each of several panels A-D of alternative tip configurations for the EP catheter.

Description of the Preferred Embodiment Fig. 1 shows the electrophysiology catheter 10 in isolation. The distal tip 17 forms a substantially semi-circular shape when fully deployed. The most distal section of the device 22 is substantially collinear and parallel to the shaft 24 of the catheter body. The distal loop 17 includes one or more electrodes typified by electrode 18 which are electrically coupled to a proximal connector plug 25 at the proximal end 15 of the catheter. A strain relief 26 is used to mechanically decouple the connector plug 25 from the catheter body 24. It is important to note that the cross section of the catheter body 24 lies in approximately the same plane as the most distal tip section, also shown in the Fig. 2. As seen in the figure a distal ablation electrode may be optionally applied to the device 10 as indicated by ablation electrode 11.

Fig. 2 shows the cross section of the catheter body 24 midspan down the length of the catheter revealing the metal core 19, which is preferably of a "shape memory" metal material such as nitinol and which can be used to form a super elastic tip 17 allowing the device to adopt a straight configuration for passage through the lumen of guiding device while forming the appropriate semicircular loop upon deployment. Although Nitinol is preferred certain stainless steel materials also appear to be promising. Each individual electrode 18 is electrically coupled to the connector plug 25 through the use of a connection wire typified by wire 20 that will be insulated from the core wire 19 and embedded in a polymer 13 that traps the wires next to the core and forms the exterior surface of the catheter 10. The polymer layer 13 may be extruded over the wires to encapsulate the assembly, which allows for a reduction in device profile.

Fig. 3 shows the distal tip section 17 in isolation revealing the torrorial or semi-circular shape 14 of the device. It is important to note that the cross section of the catheter body 24 lies in approximately the same plane as the most distal tip section, also shown in the Fig. 2. The offset 23 seen in Fig. 2 is intended to allow the arcuate shape of the distal tip 14 to be manipulated into the ostium of the target vessels. This offset may vary from zero to relatively large value as seen in the figure. These design features when taken together permit the electrophysiology catheter 10 to function not only as a mapping and measurement device but also as a stabilizing guidewire-like device replacing the guidewire function for the therapy catheter during portions of the procedure. The invention is described in general in combination with the treatment of arrthymias originating from accessory pathways located around the pulmonary vein in the atrium of a patient. The device is disclosed in the context of a cryogenic catheter type ablation device, although it must be understood that other forms of ablation are carried out at the pulmonary vein including radio-frequency ablation, thermal ablation and the like. Although a cryogenic therapy catheter is shown for purposes of illustration and explanation, it should be recognized that other ablation therapy devices can be used in carrying out the invention. In a similar fashion the distal tip configuration is illustrated primarily as a loop or torus shape. This shape is very desirable for use in the pulmonary vein but other target vessels and other tip configurations are contemplated within the scope of the invention and illustrated in the figures. Therefore it is important to note that the examples are illustrative and intended to limit the scope of the invention.

Fig. 4 shows a curved segment of the atrium 30 of a patient and the osteum 31 of the pulmonary vein. The vein itself 32 is shown extending away from the surface 30 and is shown in cross hatch. An anatomic site near the ostium of the pulmonary vein would represent an electrically active area that requires ablation.

Fig. 5 shows the use of a guidewire 40 to access the pulmonary vein through a guide sheath 41. Once the guidewire is in place the therapy catheter 42 is passed over the guidewire and it is passed out of the lumen of the guide sheath 41 as indicated by motion arrow 43.

Fig. 6 shows the therapy catheter 42 in an inflated condition with the therapy delivery balloon 44 approaching the ostium of the pulmonary vein as indicated by motion arrow 45. In this figure the therapy device is approaching the ostium by being passed over the guidewire, which remains relatively stationary in the pulmonary vein.

Fig. 7 is shows the partial retraction of the therapy balloon as indicated by motion arrow 47 after the delivery of sufficient energy to ablate the accessory pathway. It is difficult to illustrate "ablation" but it is expected that at troroidal zone of tissue or annuls of ablated tissue will be created and in the figure a portion of the annular torus is shown at item 48.

It would be conventional practice at this point to exchange the therapy balloon for a conventional mapping catheter to determine whether or not the ablation was successful in quieting the passage of electrical signals around the ostium of the pulmonary vein.

In contrast in the present invention the guidewire itself may be withdrawn and be replaced by the EP catheter 10 as seen in Fig. 8. With the therapy catheter inflated and located loosely in the ostium of the pulmonary vein the guidewire may be safely removed and placed with the EP catheter 10 that is shown emerging from, the access lumen of the therapy catheter in Fig. 8 indicated by motion arrow 52.

Fig. 9 is a highly schematic view of the operation of the system with the therapy balloon more fully retracted than would be achieved in practice to simplify the figure, thus showing the complete engagement of the EP catheter 10 with the pulmonary vein proximate the ostium of the vessel. The EP catheter may be moved and manipulated to more fully map the ostium as indicated by motion arrow 60.

Fig. 10 A-D shows alternate tip configurations useful in alternate vessels.

Claims

What is claimed:

1. A catheter comprising: an elongate catheter body having a distal end and a proximal end; a center core wire extending from the distal end to the proximal end; a plurality of signal wires extending from a connector located at the proximal end to an array of electrodes located proximate the distal end; said center wire formed of a shape memory material forming an arcuate loop that is substantially circular and orthogonal to the axis of the catheter body.

2. A system including: a therapy catheter having a guidewire lumen; an EP catheter having an elongate catheter body having a distal end and a proximal end; a center core wire extending form the distal end to the proximal end; a plurality of signal wires extending from a connector located at the proximal end to an array of a plurality of electrodes located proximate the distal end; said center wire formed of a shape memory material forming an arcuate loop that is substantially circular and orthogonal to the axis of the catheter body; whereby said EP catheter can pass through said guidewire lumen.

3. A method of treating a pulmonary vein comprising the steps of: placing a guidewire in the pulmonary vein; passing a therapy catheter over the guidewire to the ostium of the pulmonary vein; delivering an ablation therapy to the ostium of the pulmonary vein; withdrawing the guide wire and replacing it with an EP catheter of the type having an elongate catheter body having a distal end and a proximal end; a center core wire extending form the distal end to the proximal end; a plurality of signal wires extending from a connector located at the proximal end to an array of a plurality of electrodes located proximate the distal end; said center wire formed of a shape memory material forming an arcuate loop that is substantially circular and orthogonal to the axis of the catheter body.