CA2118725A1

CA2118725A1 - Catheter for electrophysiological procedures

Info

Publication number: CA2118725A1
Application number: CA002118725A
Authority: CA
Inventors: William W. Cimino; Robert M. Abrams; Miriam H. Taimisto; Marc Jensen; Patrick E. Macaulay
Original assignee: William W. Cimino; Robert M. Abrams; Miriam H. Taimisto; Marc Jensen; Patrick E. Macaulay; Heart Rhythm Technologies, Inc.
Current assignee: Heart Rhythm Technologies Inc
Priority date: 1993-03-12
Filing date: 1994-03-10
Publication date: 1994-09-13
Also published as: EP0616794A1; US5364352A; US5662606A; EP0898940A1; JPH0788093A

Abstract

ABSTRACT

A catheter adapted to perform electrophysiological procedures comprises a body member, a manipulation handle attached to the proximal end of the body member for applying torque to the body member, the handle having a control knob adapted for control movements in a first plane and in a second plane simultaneously. A deflection control line is attached at its distal end to the distal portion of the catheter and its proximal end attached to the control device of the handle so that tension applied to the control line by sliding the control knob causes deflection of the distal portion of the catheter. A stiffening member is disposed within the body member of the catheter and is slidable, said stiffening member providing increased rigidity to the portion of the body member in which the stiffening member is located. Rotation of the control knob controls the positionof the stiffening member in the body member. In a further aspect, a stiffening member in accordance with one embodiment includes a tapered distal end section with a ball formed on the distal tip, the tapered section terminating at the ball.
In accordance with another aspect, the torsional rigidity of the catheter body is increased by use of a layer of aramid fibers mixed with an epoxy. In yet anotherfeature, the handle and rotatable sliding element are symmetrically shaped to facilitate complete single-handed operation of the handle by the physician of all position control aspects of the catheter.

Description

~` 2~1~72~

CATHETER FOR ELECTROPHYSIOLOGICAL PROCEDURES

BACKGROUND
The invention relates generally to catheters, and more particularly, to steerable catheters for performing electrophysiological procedures, such as mapping electrical signals emitted from conductive cardiac tissue and ablating aberrant cardiac tissue at the point of arrhythmia origination in order to terminate 5 the arrhythmia.
The heart beat in a healthy human is controlled by the sinoatrial node (S-A
node) located in the wall of the right atrium. The S-A node generates action potentials which are transmitted through pathways of conductive heart tissue in the atrium to the atrioventricular node (A-V nGde) which in turn transmits the signals 10 throughout the ventricle by means of the His and Purkinje conductive tissues.Impropeir growth of or damage to the conductive tissue in the heart can interfere with the passage of electrical signals from the S-A and A-V nodes resulting in dist~lrbances to the normal rhythm of the heart, referred to as cardiac arrhythmia.
If the arrhythmia is refractory to medication, an alternative treatment is to 15 ablate the aberrant conductive tissue. However, that aberrant tissue must first be located. One techniqlle involves the electrical mapping of signals emanating from conductive cardiac tissue to locate the aberrant tissue causing the arrhythmia.
Ablation may then be performed. Ablation of the aberrant conductive tissue usually controls the arrhythmia and allows the heart rhythm to return to an 20 acceptable level.

7 ~ ~
.

One conventional method for mapping the electrical signals from conductive heart tissue is to provide an array of electrodes on the distal extremity of a catheter and place those electrodes in contact with the interior of a patient's heart. Typically, the catheter is introduced into the cardiovascular system of the S patient through a blood vessel and advanced to an endocardial site such as theatrium or ventricle of the heart. When placed into the blood vessel, the catheter must follow the irregularly shaped path defined by the blood vessel and branch vessels until the distal end of the catheter reaches the desired location. To assist in steering the catheter, some catheters have a curved distal tip. While this pre-10 forrned curve may fit the curves of some blood vessels, it rarely fits all anatomicalpossibilities. Greater freedom of movement is desirable.
To achieve greater control over the movement of the catheter in steering it through the cardiovascular system to the desired location in the patient, prior catheters have used guide wires to selectively vary the shape of the distal tip of 15 the catheter. In another technique, a control line is attached at a point adjacent the distal tip of the catheter. Pulling the proximal end of the control line causes ~e distal tip of the catheter to bend in one direction. Other designs have used multiple control lines to obtain bending in multiple directions; however, the size of the catheter increases. Larger catheters are undesirable due to the difficulties 20 involved in moving them through the patient's cardiovascular system and the increased blockage to blood flow. While the control line approach provides increased freedom of control over the movement of the distal end of the catheter, its effect in prior techniques is Ihnited to an arc with a fixed radius.
In another technique, a mandrel or guide wire is also located in the catheter 25 in addition to the control line and is moved to alter the radius of bend of the distal end of the catheter. The mandrel would be moved more towards the distal end or more towards the proximal end of the catheter to alter the radius of bend of the 21~72~

distal end. While such an approach has been found to yield improved control overthe movement of the distal end, the disclosed technique required that the physician use two hands to exert this control. Additionally, no means were provided for holding the mandrel and control line in position once the desired bend was obtained thereby resulting in the physician having to hold both the mandrel end and the operating mechanism of the control line. Requiring the use of two hands for the steering function alone restricts the physician from performing other tasks at the same time.
Another consideration in keeping the catheter small in size but providing an increased steering capability is the torsional rigidity of the catheter. In catheters with low torsional rigidity, torsion may accumlllate as the proximal end of the catheter is twisted by the physician. Then as the distal end finally begins rotating, the accumulated torsional molllent will tend to unwind the catheter, resulting in rapid rotation of the tip inside the blood vessel. Such unwinding may result in the distal tip of the catheter overshooting the branch vessel entrance then requiring further steering manipulation on the part of the physician lengthening the procedure. Thus it is desirable to have increased torsional rigidity of the catheter so that rotating the proxhllal end of the catheter will result in immediate rotation at the distal end; i.e., immediate torque reaction.
A further consideration in navigating the catheter into the desired position in the patient is the bending rigidity or stiffness of the catheter. In some cases, increased force is required to advance the distal end of the catheter through a certain vessel position or to hold it against a particular site such as buttressing the catheter against a wall of the aorta or against a valve lip. However, decreased bending rigidity is beneficial in some cases. Therefore it would be desirable toprovide variable bending rigidity of the catheter to provide increased steering and positioning control. Such a feature would be desirable in an electrophysiological 211~72~

procedure catheter due to the requirement for navigation completely into the heart and for contimled contact with particular tissue during the beating action of the heart. Additionally, it would be desirable to incorporate the control means overthe bending rigidity of the catheter hlto the same control device as is used for the S other steering mechanisms.
Frequently, the position of the distal portion of the catheter within the heart may have to be adjusted one or more times in order to provide a complete and cornprehensive view of the signals from the electrically conductive heart tissuewhich is necessary to detect the point where the arrhythmia originates. Once the10 origination point for the arrhythmia is detemlined, the conductive heart tissue at the site can be ablated. RF heating is one technique typically used for ablation.
Successful ablation of the conductive tissue at the arrhythmia initiation site usually terminates fhe arrhythmia or at least moderates the heart rhythm to acceptable levels. Increased and easier control over the steering and positioning of the 15 catheter would facilitate the mapping and ablation of the heart tissue.
Hence, those skilled in the art have recognized the need for a catheter for use in electrophysiological procedures which provides increased control over steering and positioning the catheter while not increasing the size of the catheter.
It has also been recognized as desirable a catheter with increased torsional rigidi~
20 and a means for providing increased control over the axial rigidity of the catheter.
The present invention fulfills these needs and others.

2 1~87~

SUMMARY
Briefly and in general terms, the present invention is directed to a catheter which is adapted to perform electrophysiological procedures, such as detecting arrhythmia and ablating conductive pathways within a patient's myocardium in 5 order to control arrhythmia. The catheter comprises a body member; a manipulation handle attached to the proximal end of the body member for applying torque to the body member, the catheter body being attached to the handle such that when the handle is rotated about its longitudinal axis, the body member rotates about its longitudinal axis in response. The handle also has a 10 control device adapted for control movements in a first plane and in a second plane simultaneously.
A deflection control line is slidable in a direction parallel to the longitudinal axis of the body member and has its distal end attached to the distal portion of the catheter and its proximal end attached to the control device of the 15 handle so that tension applied to the control line by movement of the controldevice in the first plane will cause the deflection of the distal portion of thecatheter.
A stiffening member is disposed within the body member of the catheter and is slidable in a direction parallel to the longitudinal axis of the body member, 20 said stiffening member providing increased rigidity to the portion of the body member in which the stiffening member is located. Additionally, the stiffening member is connected at its proximal end to the control device of the handle suchthat movement of the controi device in the second plane controls the position ofthe stiffening member in the body member. In a filrther aspect, a stiffening 25 member in accordance with one embodiment includes a tapered distal end section with a ball formed on the distal tip, the tapered section terminating at the ball.
The tapered section permits easier bending of this portion of the stiffening member ~-~` 21~372 ~

so ~hat as it is advanced into the body member, it may negotiate a bend in a catheter which is already in position. The ball protects the body member of the catheter from being pierced by the stiffening member as the stiffening member isadvanced and contacts a bend in the body member.
The deflection contro; line may be a wire or cable which is slidably disposed in the body member of the catheter. An open channel may be formed entirely within an inner tubular member of the body member, or may be formed in the exterior of the tubular member, and extends to the flexible distal portion of the catheter shaft where the distal end of the control line is attached. Tensionapplied to the control line by the physician operating the control device causes the flexible disLal portion of the catheter shaft to be deflected from the central longitudinal axis of the catheter shaft and thereby allows the physiciàn to control the shape of the distal extremity during the procedure which in turn facilitatessteering through blood vessels and placement of the distal extremity against thecardiac tissue within the patient's heart. The anchoring element may be a plate fixed within a transverse plane in the distal portion of the catheter shaft or acylindrical member disposed about the inner tubular member.
In accordance with another aspect, a torsion device ~or increasing the torsional rigidity of the catheter body is coupled with the body member of the catheter so that torque applied to the proximal end of the body member will be rapidly reflected at the distal end. In a further aspect, this torsional device comprises a layer of aramid fibers mixed with an epoxy, the layer being located within the body member such that rotating the handle results in rapid rotationalresponse at the distal end of the catheter. Movement of the handle in a rotational sense controls the rotational position of the distal end of the catheter and movement of the handle in a longitudinal sense control the longitudinal positionof the distal end of the catheter.

-~ 211~72~

The handle control device may comprise a rotatable slide element, the rotation of which advances or retracts the stiffening element and the sliding action of which applies or releases tension on the control line. In another feature, the range of movement of the rotatable sliding element and the coupling of the control S line thereto are selected to result in a complete release of tension on the control line when the rotatable sliding element is at one end of the range of sliding movement thereby permitting the body member to resume its substantially straightform. The range of movement caused by rotation of the rotatable slide element is also selected to permit positioning the stiffening member at a first positionresulting in a first radius of curvature of the distal end of the body member when tension is applied to the control line, and at the other end of the range, in positioning the stiffening memher at a second position resulting in a second radius of curvatllre of the distal end of the body melllber when tension is applied to the control line. The second radius of curvature is differen~ from the first radius. At positions in between the respective ends of the ranges, various bends are possible and the bending of the distal end of the catheter is continuollsly variable between the ends of the ranges. In a filrther aspect, the positioning of the stiffening rod controls the bending stiffness of the body member and the range of movement of the control device is selected to achieve a predetermined range of bending rigidity.
In yet another feahlre in accordance with the principles of the invention, the handle and rotatable sliding element are symmetrically shaped to facilitate complete single-handed operation of the handle by the physician including rotation of the handle, longihldinal movement of the handle, rotation of the rotatable sliding element, and sliding of the rotatable sliding element. The handle itselfmay be rotated about its longitudinal axis while the sliding element is being both rotated and slid. Additionally, the handle is shaped for ease in grasping and retention by the physician's hand and filrther, the rotatable sliding element is 21~8725 shaped so that it may be both rotated and slid by the digits of that same hand.
The sliding element in one aspect, has a groove formed about the outside and thetwo surfaces on either side of the groove are conveniently used by the operator to control sliding movement of the element.
S The handle may also contain indicia, such as a colored band positioned on the handle body, to indicate movement of the rotatable slide element beyond a preselected point. The handle may also incl~lde gradations to provide a visual reference system to indicate the present position of the rotatable sliding element in its range of movement.
The catheter may have one or more electrodes on a distal portion, and may have an ablation electrode provided on the distal tip for ablation of cardiac conductive pathways. One or more electrical conductors extend within the body member and are electrically connected to the electrodes on the distal portion ofthe catheter. Additional electrical conductors exeend within the body member to electrically connect the ablation electrode to an electrical source, preferably a high frequency electrical source, for providing the ablation energy.
The catheter of ~he invention allows a physician to effectively control the shape and stiffness of the catheter during electrophysiological procedures, including the detection and ablation of aberrant conductive cardiac tissue. The catheter of the present invention can be more easily manipulated within a patient's heart and allows the physician to more accurately place the catheter electrodes as desired. Other aspects and advantages of the invention will become apparent fromthe following detailed description and accompanying drawings, illustrating by way of example the features of the invention.

~ 2~18725 BRIEF DESCRIPTION OF THE DRAWINGS
FIG. I is an elevation view of an electrophysiological catheter embodying features of the invention;
FIG. 2 is an enlarged longitudinal cross-sectional view of the distal portion S of the catheter along lines 2-2 shown in FIG. I;
FIG. 3 is a transverse cross-sectional view of the distal portion of the catheter shown in FIG. 2, taken along the lines 3-3;
FIG. 4 is a schematic elevation view of a distal portion of the catheter shown in FIG. I with tension applied to a control line which extends into the distal portion of the catheter;
FIG. S is a schematic elevation view of a distal portion of the catheter similar to that shown in FIG. 4 except that a stiffening rod is advanced into the distal portion of the catheter shaft in addition to tension being applied to thecontrol line;
FIG. 6 is a schematic elevation view of a distal portion of the catheter similar to that shown in FIG. 5 except that the stiffening rod is advanced farther into the distal portion of the catheter than that shown in FIG. S;
FIG. 7 is a transverse cross-sectional view of an alternative embodiment incorporating principles of the invention;
PIG. 8 is an enlarged longitudinal view, partially in section, of a manipulating handle secured to the proximal end of the catheter as shown in FIG.I;
FIG. 9 is an exploded perspective view of the manipulating handle shown in FIG. 8;
FIG. 10 is a perspective view of the distal portion of the catheter shown in FIG. I with the jacket and a distal extremity cut away to illustrate the connection of the deflection control line to the anchor plate;

211872~
:: `

FIG. Il is a perspective view of the distal portion of an alternative catheter with the jacket and a distal extremity cut away to illustrate the connection of the deflection line to an anchor cylinder;
FIG. 12 is a perspective view of the catheter shown in FIG. I; and FIG. 13 is a view of the distal end of a tapered stiffening member having a ball formed on the distal tip.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings with more particularity, wherein like 10 reference numerals designate like or corresponding elements among the severalviews, there is shown in FIGS. 1-3, a catheter 10 usable for electrophysiological procedures and embodying features of the invention, including an elongated shaftor body member 11, a plurality of sensing electrodes 12 on the exterior of the body member along the distal portion 13 thereof and an ablation electrode 14 at 15 the distal tip of the body member 11. The tip electrode filnctions both as anablation electrode and as a sensing electrode; thus, both numerals 12 and 14 arepointing to it. The body member 11 has an inner lumen 15 which extends to the distal tip and which has disposed therein an electrical conductor 16 having a distal end electrically connected to the ablation electrode 14. Also extending within the 20 inner lumen 15 are a plurality of electrical conductors 17 which have distal ends electrically connected to the sensing electrodes 12. Although three sensing electrodes 12 and one ablation electrode 14 are shown, this is for purposes of illustration only and is not meant to be restrictive of the invention. More or fewer of each of these electrodes may be used depending on the application.
25 Additionally, the types of devices mentioned for sensing and ablation are for also only for purposes of illustration. For example, rather than using an "electrode"

~ 211~72~

for ablation, a different type of energy transducer may be incorporated into thecatheter.
The catheter body member 11 has a deflection control system 18 which has a distal end located at the distal portion 13 of the body member 11. The 5 deflection control system 18 preferably comprises a control line or deflection wire 23 and a lubricous coating or jacket 24, e.g. a suitable fluoropolymer such as poly(tetrafluoro)ethylene which is available under the trademark Teflon~ from E.I. duPont, deNemours & Company. Other fluoropolyl1lers and other lubricous materials may be utilized to coat the deflection wire 23. The jacket 24 may be 10 a lubricous sheath which allows for the movel11ent of the deflection wire 23 therein. The deflection wire 23 is fixed to an anchor member 19 in the distal portion 13 so that, when tension is applied to the deflection wire 23 by means of the manipulating knob 43 mounted on the handle 20 at the proximal end of the catheter body member 11, the flexible distal portion 13 of the body member 11 15 will be deflected from its at rest position as shown in FIGS. I and 2 to the curved shape shown in FIG. 4. Preferably, the deflection control system 18 is disposed within a lumen 21 formed in the catheter body member 11 so as to be off-set fromthe central longitudinal axis 22 of the catheter body member I I to more easily effect the deflection of the flexible distal portion 13. In the preferred embodiment 20 shown in the figures, the body member 11 is constructed so that it is substantially straight when at rest and returns to that position when bending forces have beenremoved. The deflection control system 18 is used to impart such bending forces.FIGS. I and 2 illustrate a presently preferred embodiment of the invention wherein the catheter body member 11 has an inner tubular member 25 with the 25 inner lumen 15 extending therein, an outer jacket or coating 26 on the exterior of the body member and a reinforcing tubular structure or layer 27 disposed betweenthe outer jacket or coating 26 and the inner tublllar member 25. The layer 27 is ~ 21~8725 formed of multi-filament strands 28 within a polymeric matrix 29. Preferably, the reinforcing multi-filament strands 28 are braided as shown schematically in FIGS.

3 and 7. It has been found that this constmction provides improved torsion rigidity along the entire length of the body member 11 proximal to the relatively 5 short, flexible distal portion 13. Thus, the torqlle developed by rotating themanipulation handle 20 at the proximal end of the body member l l will be quickly communicated to the distal end and the torsion storage problems experienced in the prior art are lessened. The tub1llar reinforcing structure 27terminates at a location proxhnal to the distal tip of the body member 11 to 10 provide the deflectable distal portion 13 with more flexibility.
A mandrel or stiffening member 31 is slidably disposed within a sheath 30, preferably formed of a fluoropo1ymer such as Teflon, both of which are disposed in the inner lumen 15 of the inner tubular member 25. The stiffening member is preferably formed of stainless steel, although other materials may function as well.
15 The advancement of the stiffening member 31 within the distal portion 13 of the catheter body member 11 controls the stifffiess of the distal portion and in conjunction with the deflection wire 23 controls the shape of the flexible distal portion as shown in FIGS. 4-6.
In FlG. 4 the stiffening member 31 is shown completely withdrawn from 20 the distal portion 13 of the catheter body member 11 so that tension applied to the deflection wire 23 will result in the curvature of the distal portion 13 as shown.
In the case shown in FIG. 5, the stiffening member 31 has a tapered end thus making that section more "bendable" and has been advanced into the distal portion 13. The tapered part of the stiffening member 31 has been bent and the curvature25 of the distal portion 13 is altered. Two radii of curvature are shown thus resulting in increased steering capability.

- ` 2~ ~872~

As depicted in FIG. 6, the stiffening member 31 is more stiff and has been advanced even farther into the distal portion 1~ of the body member 11. The curvature is altered again. The portion 32 of the body member which extends distal to the location of the anchor member remains essentially straight.
FIG. 13 presents an enlarged view of the stiffening member 31 of FIG. 5.
In accordance with ~is embodiment, the stiffening member 31 includes a tapered section 76 ending at a ball 78. The ball 78 will protect the catheter body from - being pierced by the stiffening member from the inside such as in the case where the catheter has already been put into a curved configuration and the stiffeningmember is being advanced into that curved section of the catheter to obtain increased bending stiffness distally. Such may occur where the distal section 32of the catheter will not remain in position against certain tissue due to heart movement. Rather than piercing the body member, the rounded distal tip of the stiffening member will negotiate the curve of the body member. The remainder of the stiffening member 31 will then follow. The tapered section 76 likewise assists the stiffening member 31 in negotiating already established bends in thecatheter. Because the tapered section is of a smaller diameter, it will bend more easily thus enabling the distal end of the stiffening member to bend around the existing catheter bend more easily. As mentioned above, a further advantage of the tapered section/ball combination is shown in FIG. S where different radii ofbends are possible thereby giving the physician greater steering control.
The deflection wire 23, the stiffening member 31, and the torque control layer 27 resulting in additional torsional rigidity, allow the physician using the catheter to more easily and accurately advance the catheter through a patient's vascular system into the beating heart. The physician can more easily adjust theshape and stiffness of the distal portion 13 of the catheter 10 to place the distal portion at a desired location against a ventricle wall for example in a desired 2~725 orientation. This degree of control provides the physician with greater versatility in accurately placing the catheter at the desired location in order to better determine the site from which the arrhytl-mia originates and lo more accurately place the ablation electrode against the originating site of the arrhythmia to effectively ablate the conductive tissue at the site to elhIlinate or moderate the arrhythmia while the heart is beating. The position of the stiffening member 31 may be adjllsted to result in greater or lesser bending stiffness as required. For example, when the catheter is placed against a beating heart and increased bending stiffness is needed to keep it in position, such stiffness may be attained by advancing the stiffening mel11ber towards the distal ens~ of th~ catheter. Whereless bending stiffness is required, the stiffening mel11ber ~nay be retracted towards the proximal end of the catheter.
FIG. 7 illustrates an alternative embodiment to the catheter body member Il construction shown in FIGS. 1-3. In this embodiment, the inner tubular member 25 is provided with a plurality of open channels fonned in its exterior which are adapted to receive the electrical conductors 16 in addition to a plurality of deflection control systems 18. In this embodiment four sensing electrodes areprovided on the distal portion of the catheter. The electrical conductor 17 connected to the ablation electrode 14 is shown extending through the central inner lumen 15. However, it may be disposed within a different channel which may be formed in the exterior of the tubular member 25 in order to provide a stiffening member within the inner lull1en 15 as in the previously discussed embodiment. The channels are closed by the tublllar layer 27.
The details of the maniplllating handle 20 on the proxh11al end of the catheter 10 are shown in detail in FIGS. 8 and 9. The handle 20 generally includes a body 40, a tublllar body mell1ber 41 having a proximal end seated within a recess provided within the body. A slide element 43 is slidably mounted about the cap 42 and an elongated female threaded element 44 which acts as a nutand which rotates within the body 40. The distal portion of the female threaded element 44 is provided with a plurality of longitudinally extending ridges 45 onthe exterior thereof which are adapted to be slidably received within the interior S surface of the slide member 43. Therefore, rotating the slide member 43 will cause rotation of the threaded element 44. A hollow male threaded element 47 is slidably disposed about the body member 41 and is threadably engaged within the female threaded element 44. The male threaded element 47 has an inward projection 48 to which the proximal end of the stiffening member 31 is suitably 10 secured such as by crimping or insert molding. A ring 49 is seated within a shoulder S0 provided on the interior of the slide element 43 and the ring 49 hasan inward projection Sl to which is secured the proximal end of the deflection wire 23. In the preferred embodiment, the shoulder is fonned by two parts fastened together by screws as shown in FIG. 8. The inward projections 48 and 15 Sl are located in the longihldinal slot 60 in the shaft 41, and are thus restricted from rotating. The proxh1lal end of the catheter body member 11 is secured to the cap 42 such as by adhesive. Therefore, rotating the handle 20 will result inrotation of the body member 11.
Longitudinal movell1ent of the slide element 43 in the proximal direction 20 by an operator will move the ring element 49 longitudinally in the proximal direction causing tension to be applied to the deflection wire 23 which is secured to the inward projection S l of the ring 49 and thereby curves the distal portion 13 of the catheter body mel11ber 11. Longihldinal movel11ent in the distal direction will lessen the tension applied to the deflection wire 23 and allow the distal 25 portion 13 to return to its normal shape, which is usllally straight. The slide element 43 includes a groove 62 into which the digit or digits of the operator may reside when moving the element. The surfaces 64 and 66 on either side of the . , ! ;~ ~ i ~ .

211872.~

groove would be used to receive the force applied by the operator's digits to move the slide element 43. This resu]ts in more positive control over the slide element and increased convenience in operation.
Rotation of the slide eiement 43 by the operator will rotate the female S threaded element 44, which in hlrn will move the hollow male threaded element 47 along the body member 41 and result in the longitudinal movement of the stiffening member 31 which is connected to the inward projection 48 on the male threaded element 47. The stiffening member 31 must have sufficient column strength to communicate the thrust applied to the proximal end to the distal end10 thereof and to otherwise stiffen the distal portion 13 of the catheter body member Il. :
Turning briefly to FIG. 12, the movement of the knob 43 in two planes can be seen. In the first plane 62, the knob 43 slides in a direction parallel to the longitudinal axis 64 of the catheter 20 for control over the deflecting wire 23, as shown by the arrows 65 drawn in parallel with the longitudinal axis. In the second plane 66, the knob 43 rotates as shown by the curved arrows 68, to control the position of the stiffening member. These planes are perpendicular to each other in this view. It may also be noted that the handle body 40 includes a larger diameter portion 70 at its proximal end. The body 40 is smoothly tapered up to that enlarged diameter portion 70. The existence of this enlarged portion 70 provides a physical indicator to the physician as to the location of his or her hand on the handle 40. The physician can tell how far back his or her hand is on the handle based on the feeling imparted to the hand by the differences in diameter along the handle.
The cap 42 or female threaded element 44 may h1clllde indicia, such as the color red, placed at a certain point 011 its outer surface to establish a position reference system. Upon moving the slide element 43 far enough distally to reveal r-- 2 1 1 8 7 2 5 the red indicia on the cap, the operator wo1lld then be made aware that he or she has reached a predetermined position. Alternately, the indicia may include gradations marked on the cap.
Electrical conductors 16 and 17 (not shown in FIG. 8 or 9~ pass through 5 the inner lumen 52 of the tubular shaft 41 and are electrically connected to the electrical connector 53 shown on the proximal end of the handle 20 in FIG. 8.
A suitable connector 53 is the Model No. V114RC72 sold by Alden Products Company, located in Brockton, Massachusetts. Other suitable electrical connectors are commercially available.
10In one presently preferred embodiment of the invention, the tubular sheath member 24 about the deflection wire 23 has an outer diameter of about 0.015 to about 0.020 inches (0.38 to 0.51 mm~ and an inner diameter of about 0.008 to about 0.012 inches (0.20 to 0.31 mm). The layer 27 formed of multi-filament strands 28 and polymer matrix 29 has a wall thickness of about 0.003 to about 150.005 inches (0.08 to 0.013 mm) and the outer jacket or coating 26 has a wall thickness of about 0.004 to 0.007 inches (0.10 to 0.18 mm). The outer diameter of the catheter may range from about 0.079 to about 0.12 inches (2.01 to 3.05 mm) and the overall length of the catheter 10 may range from about 39.4 to 51.2 inches (100 to about 130 cm). The sensing electrodes 12 on the distal end are 20 preferably fonned of platinum or a platinulll alloy and are about 0.030 to 0.079 inches (0.75 to about 2.0 mm) in width and are spaced along the length of the distal portion about 0.079 to 0.394 inches (2 to about 10 mm) apart. A preferable spacing is about 0.20 inches (5 mm). The ablation electrode which is about 0.16 inches (4 mm) long is also preferably fonned of platinum or a platinurn alloy, or 25 platinum coated stainless steel.
The inner tubular member 25 is formed from a thermoplastic elastomer having a Shore hardness from about 75A to about 75D, preferably about 85A to 211~725 about 55D and is preferably a thermoplastic polyurethane. Suitable polyurethanesinclude Tecothane~' which is available from Thermedics, Inc. Alternative materials include Pebax~ which is a thermoplastic elastomer available from the Atochem Company. The polymer matrix 29 is formed of a thermosetting polymer 5 and preferably is an epoxy adhesive such as FDA2. The multi-filament strands 28 may be forrned of high strength polymeric materials such as aramid (~Cevlar'~9) available from E.l. duPont, deNemo-lrs & Co., Inc. The fibrous strands compress into a ribbon-like shape when braided.
The outer jacket or coating 26 is preferably formed of a thermoplastic 10 polymeric material having a Shore hardness of about 85A to about 75D, jpreferably about 95A to about 65D. Suitable polymers include a polyurethane made with a polytetramethylene glycol ether which is available commercially as 2363 55DE Pellethane from the Dow Chemical Company or a polyurethane such as TT 205SD B320 Tecothane which is available from TlIermedics. Other suitable 15 thermoplastic polymeric materials may be employed.
Both the inner tubular member 25 and the outer jacket 26 may have incorporated therein a radiopaque material such as barium sulfate to facilitate the fluoroseopic observation during the procedure by the physician in attendance.
The electrical conductors 16 and 17 may be 30-40 awg copper wires with 20 a suitable insulation, such as a polyamide, polyurethane/nylon, or a fluoropolymer such as poly(tetrafluoro)ethylene. The deflection wire 23 and stiffening member 31 are formed of a stainless steel suitable for in vivo use. The deflection wire 23 is about 0.005 to about 0.010 inch (0.127 to 0.254 mm) in diameter and the stiffening member 31 is about 0.010 to about 0.020 inch (0.254 to 0.508 mm) in 25 diameter, and the lengths thereof are appropriate for the catheter in which they are utilized.

211872.5 The catheter 10 can be conveniently made by the following procedure.
Multi-filament strands 28 are braided about the inner tubular member 25 along the length thereof. The braiding may be terminated short of the distal portion 13 orthe entire length of the inner tubular melllber 25 may be braided and the braided S portion on the distal portion 13 may be removed. Matrix 29is formed either by impregnating the braided product with a suitable impregnate or incorporating matrix material with the strands prior to braiding and then heating the braided product to form the matrix. To complete the catheter body member, a heat shrinkable thermoplastic tubular member or sleeve which forms the outer jacket 26is fitted onto the braided and impregnated reinforcing layer 27, and then a heat shrinkable tubular element (not shown) is fitted over the thermoplastic tube forrning the outer jacket 26 and the assembly is then heated by hot air to shrink the heat shrinkable tube and press the thermoplastic tube against the exterior of the reinforcing layer 27 to secure the jacket 26 thereto. Upon cooling, the heat15 shrinkable tube is stripped off and discarded and the catheter is then ground to the desired outer diameter.
Electrical conductors 16 and 17 are advanced through the inner lumen 15 of the inner tubular member 25 and electrically connected by soldering to the sensing electrodes 12 and the ablation electrode 14 respectively. The electrodes20 12 are slid over the distal portion 13 and secured to the exterior thereof by a suitable adhesive. Ablation electrode 14 is shllilarly secured to the distal tip oF
the catheter after conductor 17 is soldered thereto. The stiffening member 31 ispassed proximally through the inner lulllen 15 and is secured by its proximal end to the inward projection 48 on the male threaded element 47 on the manipulating 25 handle 20 by suitable mealls SUCIl as brazing or soldering or by an adhesive. The deflection wire 23 is advanced throllgll the lumen 21. The proximal end of the deflection wire 23 is secured by the same or similar means to the inward \
211872~

projection Sl on the ring 49. The distal end of the deflection wire 23 is secured by the salne or similar means to the anchor plate 19 as shown in FIG. 10. In this instance a transverse slit is formed in the distal portion 13, the anchor plate 19 is adhesively bonded to the proximal facing of the slit and then the distal facing of S the slit is adhesively bonded to the anchor plate and the proximal facing of the slit. An alternative embodiment is shown in FIG. I l wherein an anchor cylinder S5 is provided which encircles and is secured to the inner hlbular member 25, and has a linear depression or groove 56 which is seated into the open channel 30.
In the latter instance, the deflection wire 23 is suitably secured such as by soldering within the groove 56. The anchor plate 19 and the anchor cylinder 55 may be formed of suitable high strength material such as stainless steel.
While the invention has been described herein in terms of certain preferred embodiments, those skilled in the art of catheters for performing electrophysiological procedures within a patient will recognize that various 15 modifications and improvements can be made to the invention without departingfrom the scope thereof. Although preferred and alternative embodiments of the invention have been described and illustrated, it is clear that the invention issusceptible to numerous modifications and adaptations within the ability of those skilled in the art and without the exercise of inventive faculty. Thus, it should be 20 understood that various changes in form, detail and usage of the present invention may be made without departillg from the spirit and scope of the invention.

Claims

1. A catheter for performing an electrophysiological procedure, the catheter comprising:
a body member having a distal end and a proximal end;
a manipulation handle attached to the proximal end of the body member such that when the handle is rotated about its longitudinal axis, the body member rotates about its longitudinal axis in response, the handle having a selectivelymoveable control device adapted for movement in a first plane and in a second plane simultaneously;
a deflection control line slidable in a direction parallel to the longitudinal axis of the body member, the control line having a distal end fixedly attached to the distal portion of the catheter and the proximal end attached to the control device of the handle so that tension applied to the control line by movement of the control device in the first plane will cause the deflection of the distal portion of the catheter; and a stiffening member disposed within the body member and slidable in a direction parallel to the longitudinal axis of the body member, said stiffening member providing increased rigidity to the portion of the body member in which the stiffening member is located, the sdffening member connected at its proximalend to the control device of the handle such that movement of the control devicein the second plane controls the position of the stiffening member in the body member.

2. The catheter of claim 1 wherein the handle comprises a handle body and the conirol device comprises a rotatable slide element mounted on the handlebody for rotational and sliding movement in relation thereto, wherein the rotatable slide element is coupled to both the stiffening member and the control line, andwherein the selective movement of the rotatable slide element controls both the tension on the control line and the position of the stiffening member.

3. The catheter of claim 2 wherein sliding the rotatable slide element in a first direction applies tension to the control line and sliding the rotatable slide element in a second direction releases tension from the control line.

4. The catheter of claim 2 wherein rotating the rotatable slide element in a first direction advances the stiffening element towards the distal end of the body member and rotating the rotatable slide element in a second direction retracts the stiffening element towards the proximal end of the body member.

5. The catheter of claim 2 wherein the handle and rotatable sliding element are symmetrically shaped to facilitate single-handed manipulation by the operator, including rotation of the handle, rotation of the rotatable sliding element, andsliding of the rotatable sliding element.

6. The catheter of claim 5 wherein the rotatable sliding element has a grooved surface, the groove disposed about the periphery of the element, for receiving the digit of an operator and adapted to receive the contact of the operator's digit on either side of the groove to slide the element.

7. The catheter of claim 2 wherein the range of movement of the rotatable sliding element and the coupling of the control line and the stiffening member thereto are selected so as to:

result in a complete release of tension on the control line when the rotatable sliding element is at one end of the range of sliding movement;
result in positioning of the stiffening member at a position when the rotatable sliding member is rotated to one end of its range of rotation resulting in a first radius of curvature of the distal end of the body member when tension isapplied to the control line; and result in positioning of the stiffening member at a position when the rotatable sliding membsr is rotated to the other end of its range of rotation resulting in a second radius of curvature of the distal end of the body member different from the first radius when tension is applied to the control line.

8. The catheter of claim 2 wherein the stiffening member and its connection to the handle are such that when the control device is moved to the fully retracted position for the stiffening element, the distal end of the catheter will have a first radius of deflection when tension is applied to the control line.

9. The catheter of claim 8 wherein the stiffening member and its connection to the handle is such that when the control device is moved to an intermediate position for the stiffening element, the distal end of the catheter will have a second radius of deflection for part of the distal end and a third, different radius of deflection for a second portion of the distal end when tension is applied to the control line.

10. The catheter of claim 8 wherein the stiffening member and its connection to the handle is such that when the control device is moved to the fully extended position for the stiffening element, the distal end of the catheter will have a fourth radius of deflection when tension is applied to the control line.

11. The catheter of claim 1 wherein the body member comprises means for increasing the torsion rigidity of the body member, said means comprising a reinforcing tubular structure having a layer of braided aramid fibers mixed withan epoxy.

12. The catheter of claim 2 wherein the handle further comprises indicia which indicates to the user that the rotatable sliding member has been slid beyond a predetermined point.

13. The catheter of claim 1 wherein the catheter body is formed of a material which will resume a substantially straight shape when the tension on the control line is released.

14. The catheter of claim 1 wherein the stiffening member is formed of a bendable material which bends less easily than the body member when subjected to tension on the control line.

15. The catheter of claim 1 wherein the range of movement and the material of the stiffening member are selected to result in controllable bendingrigidity of the body member.

16. A catheter for performing an electrophysiological procedure, the catheter comprising:
a body member having a distal end and a proximal end;
a manipulation handle attached to the proximal end of the body member such that when the handle is rotated about its longitudinal axis, the body member rotates about its longitudinal axis in response, the handle having a selectively moveable knob adapted for rotational movement and slidable movement simultaneously;
a deflection control line slidable in a direction parallel to the longitudinal axis of the body member, the control line having a distal end fixedly attached to the distal portion of the catheter and the proximal end attached to the knob of the handle so that tension applied to the control line by selected movement of the knob will cause the deflection of the distal portion of the catheter; and a stiffening member disposed within the body member and slidable in a direction parallel to the longitudinal axis of the body member, said stiffening member providing increased rigidity to the portion of the body member in which the stiffening member is located, the stiffening member connected at its proximal end to the knob of the handle such that selected movement of the knob controls the position of the stiffening member in the body member.

17. The catheter of claim 16 wherein sliding the knob in a first direction applies tension to the control line and sliding the knob in a second direction releases tension from the control line.

18. The catheter of claim 17 wherein rotating the knob in a first direction advances the stiffening element towards the distal end of the body member and rotating the knob in a second direction retracts the stiffening element towards the proximal end of the body member.

19. The catheter of claim 18 wherein the handle and knob are symmetrically shaped to facilitate single-handed manipulation by the operator, including rotation of the handle, rotation of the knob, and sliding of the knob.

20. The catheter of claim 19 wherein the handle further comprises indicia which indicates to the user that the rotatable sliding member has been slid beyond a predetermined point.

21. The catheter of claim 20 wherein the body member comprises means for increasing the torsion rigidity of the body member, said means comprising a reinforcing tubular structure having a layer of braided aramid fibers mixed withan epoxy.

22. A catheter for performing an electrophysiological procedure, the catheter comprising:
a body member having a distal end and a proximal end;
a manipulation handle attached to the proximal end of the body member such that when the handle is rotated about its longitudinal axis, the body member rotates about its longitudinal axis in response, the handle having a selectivelymoveable control device adapted for movement in a first plane and in a second plane simultaneously; and a stiffening member disposed within the body member and slidable in a direction parallel to the longitudinal axis of the body member, said stiffening member providing increased rigidity to the portion of the body member in which the stiffening member is located, the stiffening member connected at its proximal end to the control device of the handle such that movement of the control devicein the second plane controls the position of the stiffening member in the body member, the stiffening member having a tapered distal section with an enlarged, blunt distal tip.

23. The catheter of claim 22 further comprising a deflection control line slidable in a direction parallel to the longitudinal axis of the body member, the control line having a distal end fixedly attached to the distal portion of the catheter and the proximal end attached to the control device of the handle so that tension applied to the control line by movement of the control device in the first planewill cause the deflection of the distal portion of the catheter.

24. The catheter of claim æ wherein the handle comprises a handle body and the control device comprises a rotatable slide element mounted on the handlebody for rotational and sliding movement in relation thereto, wherein the rotatable slide element is coupled to both the stiffening member and the control line, andwherein the selective movement of the rotatable slide element controls both the tension on the control line and the position of the stiffening member.

25. The catheter of claim 22 wherein sliding the rotatable slide element in a first direction applies tension to the control line and sliding the rotatable slide element in a second direction releases tension from the control line.

26. The catheter of claim 22 wherein the handle and rotatable sliding element are symmetrically shaped to facilitate single-handed manipulation by theoperator, including rotation of the handle, rotation of the rotatable sliding element, and sliding of the rotatable sliding element.

27. The catheter of claim 22 wherein the body member comprises means for increasing the torsion rigidity of the body member, said means comprising a reinforcing tubular structure having a layer of braided aramid fibers mixed withan epoxy.