Patent Application
20220273913
The invention is directed to a catheter having a tip assembly for mapping and/or ablating regions of or near a heart.
For successfully mapping and/or ablating of regions of or near a heart, the tip assembly should ideally make contact with the surface of the heart without undue pressure. Excess pressure can result in mechanical trauma and damage to the heart and/or result in inadequate cooling of the tip of the catheter via the blood stream resulting in steam pops, char, coagulation, embolization and inadequate delivery of current for successfully ablation of the tissue. Catheter-based ablation is usually conducted within the heart. The inside of the heart is a complex three-dimensional structure with both concave, convex and tubular structures as well as multiple irregularities within the convex or on the concave structure. Further, the transition from concave to convex or into a tubular structure also results in changes in the surface contour of the inside of the heart. Depending on the mechanism of the cardiac arrhythmia, ablation may be required within a concave structure with both smooth and irregular surface contours, on a convex structure with both smooth and irregular surface contours or at the intersection of two or more complex structures. Ablation may also be required within, around and on complex three-dimensional contours created by the confluence of a concave, convex and a tubular structure which themselves may have smooth or irregular contours. Currently, available catheter technology attempts to address ablation of these various areas of the heart with an ablation tip assembly, the shape and direction of which is determined by puller wires or preset shapes where the bending modulus between the mapping or ablation section and the intermediate section is constant. The ability of the ablation section to accommodate the irregular contours within the heart is limited. Attempts to approximate and contact these complex surface contours with the ablation section may result in either no contact or excess surface pressure at the tip allow the ablation section to achieve the off axis angle from the intermediate section required to make surface contact.
A catheter design with an ablation or mapping tip assembly attached to the intermediate section by a flexible section with a modulus of elasticity that allows the tip assembly to be deflected without displacing the intermediate section of the catheter is important to successful and safe ablation. Further, it is recognized by one of ordinary skill in the art that specific arrhythmias associated with defined surface contours may be optimally addressed with a catheter where the flexible section connecting the intermediate section and the mapping and ablation assembly is off set from the intermediate section at a predefined angle either in the plane or out of the plane of the intermediate section.
Specific examples are provided below:
Atrial flutter and atrial fibrillation are common sustained cardiac arrhythmias. Atrial flutter occurs when the atria are stimulated to depolarize at 200-350 beats per minute and is maintained by macroreentrant circuits generated by electrical impulses traveling in a circular fashion around and in the atria. Atrial flutter results in poor atrial pumping since some parts of the atria are releasing while other parts are contracting. Fortunately, atrial flutter in the right atrium can be effectively treated by ablation of the inferior vena cava-tricuspid annulus isthmus to create a line of conduction block to interrupt the macroreentrant circuit. The region at or near the inferior vena cava-tricuspid annulus isthmus (hereinafter referred to as “the cava-tricuspid region”) can be difficult to map or ablate. Not only does the tissue in that region have a convex curvature contrary to the generally cavernous shape of the right atrium, the tissue surface is uneven. Therefore, it is desirable for a catheter entering the right atrium from the inferior vena cava (an entry that is below or inferior of the cava-tricuspid region) to have a catheter body that can be deflected to approximate the convex curvature of the cava-tricuspid region and a preshaped flexible off-axis catheter tip in the direction of deflection that can maintain contact with the uneven tissue as the tip is dragged along for mapping or ablation procedures.
To successfully ablate other ventricular and atrial arrhythmias, a focal lesion or a line of conduction block should be created in the generally concave cavity of the right atrium/left atrium/right ventricle/left ventricle (RA/LA/RV/LV). The tissue surface of these structures is generally uneven. Therefore, it is generally desirable to have a catheter body that can be deflected to approximate the concave curvature of the region and a pre-shaped flexible off-axis in-plane catheter tip that is opposite to the direction of deflection that can maintain contact with the uneven tissue as the tip is dragged along for mapping or ablation procedures.
In patients with refractory atrial fibrillation, the atria are stimulated to depolarize irregularly at 250-400 cycles per minute. Not every atrial activation results in a QRS complex (ventricular depolarization) because the AV Node acts as a filter. However, there are instances where it is desirable to create conduction block at or near the AV Bundle. This region of the right atrium, the atrioventricular Bundle (of His) near the Atrioventricular (AV) Node, poses similar challenges for mapping and ablation as the cava-tricuspid region. The region is also convex unlike the generally cavernous contour of the right atrium. Moreover, the atrium wall in this region is canted slightly to the anterior. Therefore, it is desirable for a catheter entering from the inferior vena cava (an entry that is also below or inferior of AV Bundle) to have a catheter body that can be deflected to approximate the convex curvature of the region and a preshaped flexible catheter tip that extends off-plane from the catheter body to circumvent the canted angle of tissue surface.
As with most catheter-based mapping and/or ablation procedures, the catheter section immediately proximal the tip may not be in contact with or supported/stabilized by any structure in the heart. Without supportive contact between this proximal catheter section and the tissue, motion of the heart during systole, diastole and respiration is not transmitted to this catheter section except by contact between tissue and the catheter tip. As the heart moves during systole, diastole and respiration, the contact pressure at the tip of the catheter may vary from excessive to nonexistent. In a catheter that approaches the atrium in a “forward” direction, the disparity between the generally motionless (or out of synch) catheter and the heart can make it difficult to maintain stable contact between the catheter tip and the atrium wall in a beating moving heart. An unsupported and thus unsynchronized catheter used in the atrium may be inadvertently advanced into the tricuspid valve. Also, nonuniform contours in the atrium can make it difficult to contact recessed areas without excess pressure on the protruding areas increasing the risk of perforation. In addition, the catheter position is maintained only by contact between the tip and the nonuniform contours causing the catheter tip to frequently lose contact with the tissue during ablation or mapping as the heart moves independently during systole, diastole and with respiration.
Accordingly, a desire exists for a catheter capable of effectively mapping and ablating complex regions such as those with a convex contour, such as the cava-tricuspid region and regions at or near the AV Bundle (of His). It is desirable that the catheter body is adapted to approximate the convex contour for improved access to the tissue of interest from the inferior vena cava, and that the catheter tip be able to maintain contact with the tissue surface without undue force and maintain stability during ablation and mapping despite the motion of beating heart in a breathing patient. A catheter of such design improves precision of mapping and/or ablation and minimizes risks of damage to the tissue, including tissue perforation and inadvertent entry into the tricuspid valve.
The present invention is directed to a catheter having a flexibly attached tip assembly either on or off axis with the body of the catheter depending on the specific application for mapping and/or ablating regions of or near a heart. A catheter for mapping and/or ablating a region of the heart comprises a catheter body with an intermediate section that is connected to a tip assembly by a highly flexible pre-shaped section. The entire intermediate section may be deflected, or the intermediate section may comprise a deflectable proximal portion and a distal portion that is straight or curved. The highly flexible section may preset the tip assembly at an off-axis and/or off-plane angles from the intermediate section.
In a first embodiment, the tip assembly is in the same plane and same direction as deflection of the intermediate section. The intermediate section when deflected approximates a generally convex or concave region of the heart with the flexibly attached ablation/mapping assembly enabling improved and safer contact of this tip assembly with irregular contours contained in or on the concave or convex structures respectively.
In a second embodiment, the intermediate section when deflected approximates a generally concave region of various heart cavities including the right atrium/right ventricle/left atrium/left ventricle (RA/RV/LA/LV) and the preset angle of the flexible section presets the tip assembly in the same plane and opposite to the direction of deflection of the intermediate section enabling improved and safer contact of the tip assembly to the walls of the cavities for ablation and/or mapping.
In a third embodiment, the intermediate section when deflected approximates the generally convex region of the cavo-tricuspid isthmus and the preset angle of the flexible section presets the tip assembly off axis in the same plane and same direction as deflection of the intermediate section enabling improved and safer contact of the tip assembly with the cavo-tricuspid isthmus for ablation and/or mapping.
In a fourth embodiment, the intermediate section when deflected approximates the generally convex region of the His area and the flexible section presets the tip assembly out of plane with the intermediate section enabling improved and safer contact of the tip assembly to the Bundle of His region.
With any of the foregoing embodiments, the intermediate section may have a distal portion with shape memory to maintain a straight configuration or a curved configuration to improve approximation to the generally convex regions of the cavo-tricuspid and HIS regions or the generally concave regions of the RA/LA/LA/LV.
A high bending modulus of the flexible section that connects the tip section for mapping and ablation to the intermediate section enables the flexible section to absorb displacement force applied to the tip assembly, without displacing the intermediate section improving tissue contact when the tip assembly encounters uneven tissue surface. The high bending modulus of the flexible section allows the tip section to be displaced while limiting the force that the tip assembly can apply to the tissue reducing the risk of any of the following: direct mechanical perforation, steam pop perforation, and burying of the tip assembly in the myocardium resulting in high temperatures, low energy delivery, thrombus and char formation.
The specific application of the catheter of the present invention determines how the flexible section connects the tip assembly to the intermediate section. Parameters of the flexible section that determine the relationship between the tip assembly and the intermediate section includes the following: a) the off plane and/or off axis angle of the flexible section to the intermediate section, b) the flexibility of the flexible section c) the lateral stability of the flexible section, and d) the length of the flexible section.
In addition, the configuration of the intermediate section to which the tip assembly is flexibly attached also impacts on the function of the tip assembly. As mentioned, the entire intermediate section may be deflectable, or only its proximal section from which a straight or curved distal section extends. In addition, how the tip assembly flexibly extends in relation to the straight or curved distal section of the intermediate section also determines the specific application. The tip assembly can be flexibly attached: a) on or off axis with the straight or curved distal section of the intermediate section, b) when off axis whether the angle is in or out of plane with any curved distal section, c) when off axis whether the off axis tip assembly is in the direction of or opposite to the direction of any curved distal section, d) the length of the tip assembly beyond the flexible section, e) the construction of the tip assembly beyond the flexible section (e.g., irrigated or irrigated with or without temperature sensors or electromagnetic sensors), f) the force required to deflect the tip assembly off axis when the tip assembly is on axis, g) the force required to deflect the tip assembly toward the axis when the tip assembly is off axis.
In one embodiment, the present invention is directed to a catheter configured for mapping and ablating a generally convex region of the heart, such as the complex intersection of the inferior vena cava, RA, and RV at the cavo tricuspid isthmus. In a detailed embodiment, the catheter has an intermediate section and a tip assembly adapted for mapping and/or ablation that is attached to the intermediate section by a pre-shaped flexible section that allows the tip assembly to be moved generally independently of the intermediate section. In a more detailed embodiment, the catheter comprises an elongated flexible tubular catheter body having proximal and distal ends. The intermediate section is mounted on the distal end of the tubular body and deflected with a curvature that approximates the generally convex contour of the cavo-tricuspid isthmus or Bundle of His region of the right atrium. The tip assembly is attached to the end of the intermediate section by the flexible section which is configured with preset angles to extend the tip assembly off-axis and/or off-plane from the intermediate section so that the tip assembly can make suitable contact with the tissue surface of the isthmus and His region.
When deflected, the intermediate section of the catheter is configured to conform to the generally convex region so that motion of the heart is transferred to the catheter thereby providing stability to the tip assembly. The preshaped flexible section improves the ability of the tip assembly to access, contact and remain in contact with surrounding tissues of variable contour without undue pressure. Moreover, the preshaped flexible section may be reinforced to provide the tip assembly with stability in a selected angle. Accordingly, the catheter of the present invention has improved safety features and improved ablation and mapping capabilities.
In another embodiment of the convex design, the tip assembly is configured as an ablation assembly that may be irrigated, comprising a plurality of irrigation ports in between which an ablation coil electrode is wound. A porous covering, preferably made of expanded polytetrafluoroethylene, covers the coil electrode and irrigation ports. Fluid passes through the irrigation ports to the porous covering, which then disperses the fluid around the ablation assembly. This irrigation generally enables the creation of deeper lesions.
In use, the distal end of the catheter is inserted into a patient's body and advanced atraumatically into the right atrium of a patient's heart by entry from the inferior vena cava.
The intermediate section is deflected onto or near a generally convex such as the cava-tricuspid isthmus or the His region. The off-axis angle of the tip assembly readily allows the tip assembly to contact the isthmus, whereas the off-plane angle of the tip assembly readily allows the tip assembly to contact the His region notwithstanding the awkward angle imposed on the catheter by the relative superior and/or anterior locations of these regions of interest relative to the inferior vena cava.
As the user operates the catheter and maneuvers the tip assembly, the deflected intermediate section advantageously synchronizes the catheter and the tip assembly with the motion of the heart while the pre-shaped flexible section advantageously allows the tip assembly to flex from the preset angle(s) as needed in order to remain in contact with the tissue. In one embodiment, as the tip assembly encounters protrusions and recesses while being dragged along the tissue surface, the tip assembly is jarred from its preset off axis angle but the flexible section allows the tip assembly to conform and ride along on the uneven surface without displacing the intermediate section.
By adjusting the preset angles of the flexible section, the off-axis and/or off-plane angles of the tip assembly the catheter can be adapted to ablate and/or map most if not all convex regions in the right atrium. Accordingly, improved focal and linear ablation and mapping can be accomplished with the catheter of the present invention despite convex contour or uneven tissue surface.
In yet another embodiment, the present invention is directed to a catheter configured for mapping and ablation a generally concave or tubular region of the heart, such as the cavity of the RA, RV, LA, LV, IVC or SVC or other tubular structures. In a detailed embodiment, the catheter has an intermediate section and a tip assembly adapted for mapping and/or ablation that is attached to the intermediate section by a pre-shaped flexible section that allows the tip assembly to be moved generally independently of the intermediate section. In a more detailed embodiment, the catheter comprises an elongated flexible tubular catheter body having proximal and distal ends. The intermediate section is mounted on the distal end of the tubular body and deflected with a curvature that approximates the generally concave contour of the cavitary or tubular structure. The tip assembly is attached to the end of the intermediate section by the flexible section which is configured with preset angles to extend the tip assembly off-axis and/or off-plane from the intermediate section so that the tip assembly can make suitable contact with the tissue surface of the cavitary or tubular structure
When deflected, the intermediate section of the catheter is configured to conform to the generally concave or tubular region so that motion of the heart is transferred to the catheter thereby providing stability to the tip assembly. The preshaped flexible section improves the ability of the tip assembly to access, contact and remain in contact with surrounding tissues of variable contour without undue pressure. Moreover, the preshaped flexible section may be reinforced to provide the tip assembly with stability in a selected angle. Accordingly, the catheter of the present invention has improved safety features and improved ablation and mapping capabilities.
In another embodiment, of the concave design the tip assembly is configured as an ablation assembly that may be irrigated, comprising a plurality of irrigation ports in between which an ablation coil electrode is wound. A porous covering, preferably made of expanded polytetrafluoroethylene, covers the coil electrode and irrigation ports. Fluid passes through the irrigation ports to the porous covering, which then disperses the fluid around the ablation assembly. This irrigation generally enables the creation of deeper lesions. In use, the distal end of the catheter is inserted into a patient's body and advanced atraumatically into cavity or tubular structure. The intermediate section is deflected onto or near a generally concave structure such as the RA, RV, LA, LV, SVC or IVC or other cavitary or tubular structures. The off-axis angle of the tip assembly readily allows the tip assembly to contact the surface notwithstanding the awkward angle imposed on the catheter by surface irregularities.
As the user operates the catheter and maneuvers the tip assembly, the deflected intermediate section advantageously synchronizes the catheter and the tip assembly with the motion of the heart while the pre-shaped flexible section advantageously allows the tip assembly to flex from the preset angle(s) as needed in order to remain in contact with the tissue. In one embodiment, as the tip assembly encounters protrusions and recesses while being dragged along the tissue surface, the tip assembly is jarred from its preset off axis angle but the flexible section allows the tip assembly to conform and ride along on the uneven surface without displacing the intermediate section.
By adjusting the preset angles of the flexible section, the off-axis and/or off-plane angles of the tip assembly the catheter can be adapted to ablate and/or map most if not all concave regions. Accordingly, improved focal and linear ablation and mapping can be accomplished with the catheter of the present invention despite concave contour or uneven tissue surface.
These and other features and advantages of the present invention will be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein:
Referring to
Referring to the embodiment of
In accordance with a feature of the present invention, the flexible section 19 is preshaped with a configuration that attaches the tip assembly 17 of this embodiment at a predetermined off-axis angle relative to the intermediate section 14 in a direction of the deflection of the intermediate section. Moreover, the flexible section 19 has a bending modulus greater than that of the intermediate section 14 so the tip assembly 17 can flex and adjust to the contour of the isthmus tissue surface independently of the intermediate section 14. As shown in
In the embodiment illustrated in
Referring to
In the illustrated embodiments of
With reference to
The outer diameter of the catheter body 12 is not critical, but is preferably no more than about 9 french, more preferably about 7 french. Likewise, the thickness of the outer wall 20 is not critical, but is thin enough so that the central lumen 18 can accommodate a puller wire, one or more lead wires, and any other desired wires, cables or tubes. If desired, the inner surface of the outer wall 20 is lined with a stiffening tube 21 to provide improved torsional stability. A particularly preferred catheter 10 has an outer wall 20 with an outer diameter of from about 0.090 inches to about 0.094 inches and an inner diameter of from about 0.061 inches to about 0.065 inches.
The intermediate section 14 comprises a short section of tubing 22 having multiple lumens, as shown in
The useful length of the catheter 10, i.e., that portion that can be inserted into the body excluding the tip assembly 17, can vary as desired. Preferably the useful length ranges from about 110 cm to about 120 cm. The length of the intermediate section 14 is a relatively small portion of the useful length, and preferably ranges from about 3.5 cm to about 10 cm, more preferably from about 5 cm to about 6.5 cm.
A preferred means for attaching the catheter body 12 and the intermediate section 14 is illustrated in
If desired, a spacer (not shown) can be located within the catheter body between the distal end of the stiffening tube 21 and the proximal end of the intermediate section 14. The spacer provides a transition in flexibility at the junction of the catheter body 12 and intermediate section 14, which allows the junction to bend smoothly without folding or kinking. A catheter having such a spacer is described in U.S. Pat. No. 5,964,757, the entire disclosure of which is incorporated herein by reference.
As shown in
A compression coil 66 is situated within the catheter body 12 in surrounding relation to the puller wire 64, as shown in
The compression coil 66 is anchored to the outer wall of the catheter body 12 by proximal glue joint 70 and at its distal end to the intermediate section 14 by distal glue joint 71. Both glue joints 70 and 71 preferably comprise polyurethane glue or the like. The glue may be applied by means of a syringe or the like through a hole made between the outer surface of the catheter body 12 and the central lumen 18. Such a hole may be formed, for example, by a needle or the like that punctures the outer wall 20 of the catheter body 12 which is heated sufficiently to form a permanent hole. The glue is then introduced through the hole to the outer surface of the compression coil 66 and wicks around the outer circumference to form a glue joint about the entire circumference of the compression coil.
Longitudinal movement of the puller wire 64 relative to the catheter body 12, which results in deflection of the intermediate section 14, is accomplished by suitable manipulation of the control handle 16. Examples of suitable control handles for use in the present invention are disclosed in U.S. Pat. Nos. Re 34,502 and 5,897,529, the entire disclosures of which are incorporated herein by reference. As mentioned, deflection of the intermediate section 14 by longitudinal movement of the puller wire 64 allows the intermediate section 14 to generally approximate and conform to the convex curvature of the isthmus. As such, the deflected intermediate section 14 can sit on the isthmus and transmit the motion of the heart during systole, diastole and respiration to the entire catheter. The distal tip of the catheter is thus both stable and moves in synchrony with the heart. This allows the tip assembly of the catheter to conform to irregularities without undue pressure reducing the risk of any of the following: a) direct mechanical perforation because the flexible section readily flexes so as to reduce the maximal tip pressure that can be applied by the proximal portion of the catheter, b) perforation due to steam pop, as the flexible section allows the tip assembly to be displaced off the surface allowing the steam to exit into the right atrium rather than the tip pressure forcing the steam into the myocardium and out into the pericardial space; c) impedance rise, excess temperature, thrombus and char formation, as the maximum tip pressure is limited by the flexible section reducing the likelihood of the tip assembly being buried in the tissue, reducing cooling by the circulating blood.
In accordance with another feature of the present invention, the tip assembly 17 is attached to the intermediate section 14 by the pre-shaped flexible section 19. As shown in
The flexible section 19 is constructed with sufficient shape memory and/or sufficient flexibility and elasticity so that the tip assembly 17 can temporarily assume a different (greater or lesser) angle θ as needed for the tip assembly to pivot at its proximal end. The flexible section 19 can be sufficiently soft to allow the tip assembly 17 to be displaced from its preset off-axis angle θ to an on-axis angle where θ is about zero, and sufficiently elastic to return (or at least bias the return of) the tip assembly 17 to its preset off-axis angle θ thereafter, whether the displacement was caused by a formation 37 in the tissue surface, the tip assembly being caught or buried in the surrounding tissue, or a “steam pop” where a build up of pressure dislodges the tip assembly from tissue contact. To that end, the flexible section 19 has a relatively high flexural modulus measuring on a Durometer scale no greater than about 25 D to 35 D and/or no greater than about ½ to ¼ of the Durometer measurement of the intermediate section 14. The flexible section 19 acts as a “shock absorber” when the tip assembly is jarred or otherwise displaced from its preset position. The flexible section 19 enables the tip assembly 17 to pivot away from the recess 37 independently of the intermediate section 14 so that the tip assembly can remain in contact with the tissue. Referring to
As understood by one of ordinary skill in the art, the shape memory of the material 45 of the flexible section 19 also allows the catheter to be advanced atraumatically in the patient's body in a generally straight configuration through a vein or artery and yet be able to assume its preformed shape when it reaches the heart.
Referring to
The His region 43 is accessible to the catheter 10 despite the catheter's entry to the atrium from the inferior vena cava 15 and the catheter's forward approach to the His region. As with the foregoing embodiment, the intermediate section 14 is deflected so the tip assembly 17 can reach the His region. Where the deflected intermediate section 14 can approximate and assume a convex curvature near the His region, motion of the heart is transferred to catheter to stabilize the catheter. In accordance with a feature of the present invention, contact between the tip assembly 17 and tissue surface of the His region 43 is enabled by an off-plane extension of the tip assembly 17 (which may or may not also extend at an off-axis angle from the intermediate section 14). The highly flexible section 19 between the tip assembly 17 and the intermediate section 14 allows the tip assembly to maintain contact with the His tissue surface despite the uneven and nonuniform surface of the His region which has recesses and protrusions that are encountered by the tip assembly 17 as it is dragged along to map and/or ablate the His region.
Referring to
As illustrated in
It is understood by one of ordinary skill in the art that the off axis angle θ and the off-plane angle γ may be preset independently of one another. That is, the catheter 10 of the present invention may have the tip assembly 17 extend from the intermediate section 14 at any combination of the angle θ and the angle γ in accordance with their respective ranges set forth above, as desired or appropriate. In one embodiment of the catheter 10 for use in ablating and/or mapping the His region, the angle θ is about 20 degrees and the angle γ is about 90 degrees.
As mentioned, the flexible section 19 allows the tip assembly to be displaced without displacing the intermediate section 14. In one embodiment, the tip assembly 17 can be displaced from its preset off-axis and/or off-plane angle under a force or weight of merely about 0.25 to about 2.0 oz, and more preferably about 1.0 ounce. As such, the flexible section 19 provides sufficient flexibility to reduce the risk of injury that can result from the tip assembly 17 inadvertently perforating tissue or being buried in the tissue and overheating. As understood by one of ordinary skill in the art, the force required to displace or capable of displacing the tip assembly from the preset angle(s) also depends on the point of application of the force to the tip assembly, as well as the length of the tip assembly.
The flexible section 19 comprises a short section of material 45 (e.g., tubing) with a central lumen 47 through which the lead wire(s) 50, thermocouple wires 53 and 54, sensor cable 74 and irrigation tube 61 extend distally and connect to the tip assembly 17. A junction 25 of the intermediate section 14 and the flexible section 19 is shown in
Moreover, where desirable or appropriate, lateral stability can be provided in the tip assembly 17 with the use of struts or ribbons 51 provided in walls of the material 45 of the flexible section 19, as shown in
Recognizing that atria and isthmuses can come in different shapes and sizes, the intermediate section 14 may have a length ranging between about 1.0 cm and 20 cm, preferably between about 4.0 cm and 16 cm, and more preferably between about 7.0 cm and 12 cm. The intermediate section 14 may assume a “J” curve when deflected for flutter treatment and procedures and a “D” curve for HIS treatment and procedures. However, it is understood that the intermediate section and its deflection curvature may assume a variety of sizes and shapes as desirable or appropriate for the intended region of ablation or mapping.
In addition, as shown in
In illustrated embodiment, the tip assembly 17 comprises a short section of material tubing 61 (e.g., tubing) (
In the disclosed embodiment, the ablation assembly 17 is irrigated and comprises a plurality of irrigation ports 80 disposed along most of the length of the ablation assembly 17 through which fluid can pass to the outer surface of the ablation assembly to cool the ablation site. In the illustrated embodiment, the coil and the irrigation ports 80 are arranged so that an irrigation port lies between each wind of the coil electrode 82. The irrigation ports may comprise round holes formed on the surface of the tubing 61 on the side of the ablation assembly 17 in communication with the fourth lumen 35A which is supplied fluid by the irrigation tube 61 whose distal end is slightly proximal of the most proximal irrigation port. Any number of irrigation ports 80 may be used. In the illustrated embodiment, the tubing 61 of the ablation assembly 17 is configured with about 10 irrigation ports 80. The circumference of each round hole can measure about 20/1000 inch. As shown in
A tip electrode lead wire 50 (
As shown in
Any conventional temperature sensors, e.g. thermocouples or thermistors, may be used. In the embodiment shown in
Additional electrodes may be incorporated depending on the application electrode width and spacing, as well as the preferences of the operator of the catheter. If desired, one or more mapping and/or ablation ring electrodes can be mounted on the tubing 45 of the flexible section 19 and tubing 61 of the ablation assembly 17, as shown in
In other embodiment, the tip assembly 17 whether adapted for mapping or ablation may be constructed with or without irrigation, with or without temperature sensors, using suitable ring electrodes for sensing and/or ablation, as understood by one of ordinary skill in the art. The relationship between the tip assembly and the flexible section remains generally as described herein.
In addition, as better shown in
In
As shown in
As shown in
The electromagnetic sensor 72 is connected to an electromagnetic sensor cable 74, which extends through the third lumen 34a in the ablation assembly 17, the central lumen 47 of the flexible section 19, the third lumen 34 of the intermediate section 14, through the catheter body 12, and out through the control handle 16. The electromagnetic sensor cable 74 comprises multiple wires encased within a plastic covered sheath. In the control handle 16, the sensor cable 74 is connected to a circuit board (not shown). The circuit board amplifies the signal received from the electromagnetic sensor 72 and transmits it to a computer in a form understandable by the computer. Because the catheter is designed for a single use only, the circuit board may contain an EPROM chip which shuts down the circuit board approximately 24 hours after the catheter has been used. This prevents the catheter, or at least the electromagnetic sensor from being used twice.
Suitable electromagnetic sensors for use with the present invention are described, for example, in U.S. Pat. Nos. 5,558,091, 5,443,489, 5,480,422, 5,546,951, and 5,391,199, the disclosures of which are incorporated herein by reference. A preferred electromagnetic sensor 72 has a length of from about 6 mm to about 7 mm, preferably about 5 mm, and a diameter of about 1.3 mm.
In
In use, the catheter 10 is inserted into the patient through a suitable guiding sheath whose distal end is positioned at a desired mapping or ablating location. An example of a suitable guiding sheath for use in connection with the present invention is the Preface™ Braided Guiding Sheath, commercially available from Biosense Webster, Inc. (Diamond Bar, Calif.). The distal end of the sheath is guided into one of the atria. A catheter in accordance with the present invention is fed through the guiding sheath until its distal end extends out of the distal end of the guiding sheath. As the catheter 10 is fed through the guiding sheath, the tip assembly 17, the flexible section 19 and the intermediate section 14 are generally straightened to fit through the sheath. Once the distal end of the catheter is positioned at the desired mapping or ablating location, the guiding sheath is pulled proximally, allowing the deflectable intermediate section 14, the flexible section 19 and the tip assembly 17 to extend outside the sheath, and return to their original preformed shapes with the tip assembly 17 extending from the intermediate section 14 at a predetermined off-axis angle θ and/or off-plane angle γ.
In one embodiment, where the catheter is advanced into the right atrium, the intermediate section 14 is deflected to approximate the generally convex curvature of the cavo-tricuspid isthmus or the His region where the intermediate section 14 can rest on the tissue and is stabilized and in synch with the motion of the heart.
With the intermediate section 14 deflected, the tip assembly 17 makes contact with tissue in the region by means of the preset off-axis and/or off-plane angle(s) provided by the flexible section 19. To create generally focal lesions during ablation, the ablation assembly is positioned and the flexible section 19 allows the ablation assembly to be readily displaced from contact with the tissue before damage can occur from perforation, steam build-up and the like. For continuous lesions during ablation, the tip assembly 17 is dragged along the tissue surface. As the ablation assembly encounters uneven formation such as a projection or recess in the tissue surface, the flexible section 19 flexes as the ablation assembly 17 pivots from the preset angle(s) to absorb the movement without affecting the intermediate section 14. The catheter body may also be rotated to form a linear line of block at the His region. Because the off-plane angle allows the ablation assembly to reach tissue lateral of the plane of deflection, rotation of the ablation assembly (e.g., by rotation of the catheter body and/or the control handle) can create a generally linear ablation line.
Regardless of the ablation lesion desired, the tip assembly 17 maintains continuous contact with the tissue for improved lesions. In the embodiment of the catheter for mapping applications, similar manipulations of the catheter and the control handle enable the mapping electrodes 85A, 85b, 86a, 86b and 86c to map in a linear or circumferential pattern.
The preceding description has been presented with reference to presently preferred embodiments of the invention. Workers skilled in the art and technology to which this invention pertains will appreciate that the Figures are not necessarily to scale and alterations and changes in the described structure may be practiced without meaningfully departing from the principal spirit and scope of this invention. Accordingly, the foregoing description should not be read as pertaining only to the precise structures described and illustrated in the accompanying drawings, but rather should be read consistent with and as support for the following claims which are to have their fullest and fairest scope.
The present application is Divisional Application under 35 U.S.C. § 121 of U.S. patent application Ser. No. 15/935,839, filed Mar. 26, 2018, which is a Continuation Application under 35 U.S.C. § 120 of U.S. patent application Ser. No. 11/323,908, filed Dec. 29, 2005, now abandoned. The entire contents of these applications are incorporated by reference herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15935839 | Mar 2018 | US |
| Child | 17747393 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11323908 | Dec 2005 | US |
| Child | 15935839 | US |
