BI-MODAL LINEAR AND LOOP ABLATION CATHETER, AND METHOD
Medical devices, systems, and methods for treating patients with tissue ablation include catheter systems having hi-modal steering mechanisms, which are capable of both linear and loop ablation. In other words, the catheter system may have two different steering modes: two-dimensional and three-dimensional. In the first and second steering modes, the steering actuator may cause one or more portions of the catheter shaft to bend in different planes. A steerable ablation catheter may include treatment elements such as electrodes at its distal end and along the catheter shaft, each of which may map, pace, and ablate. Optional features include a series of thermocouples for monitoring local temperatures.
This application is a divisional of and claims priority to patent application Ser. No. 12/546750, filed Aug. 25, 2009, entitled BI-MODAL LINEAR AND LOOP ABLATION CATHETER, AND METHOD, the entirety of which is incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENTNot applicable.
FIELD OF THE INVENTIONThe present invention relates generally to medical devices, and more particularly to steerable catheters, systems, and methods for treating patients through ablation of tissue.
BACKGROUND OF THE INVENTIONNumerous procedures involving catheters and other minimally invasive devices may be performed to provide a wide variety of medical treatments, such as ablation, angioplasty, dilation and others. The term “atrial fibrillation” is a type of cardiac arrhythmia, or irregular heartbeat, in which the atria fail to contract effectively. Normal sinus rhythm of the heart begins with an electrical impulse generated by the sinus node that propagates across the right and left atria (the two small upper chambers of the heart) to the atrioventricular node. Atrial contraction leads to pumping blood into the ventricles in synchronization with the electrical pulse.
During atrial fibrillation, disorganized electrical conduction in the atria causes rapid uncoordinated contractions, resulting in suboptimal pumping of blood into the ventricle. The atrioventricular node may receive sporadic electrical impulses from many locations throughout the atria, instead of only from the sinus node. This electrical confusion may overwhelm the atrioventricular node, producing an irregular and rapid heartbeat. Consequently, blood may pool in the atria and increase a risk for blood clots.
While there are numerous variations of atrial fibrillation with different causes, they all involve irregularities in the transmission of electrical impulses through the heart. As a result, the heart does not pump the blood properly, and it may pool and clot. If a blood clot forms and moves to an artery in the brain, atrial fibrillation can lead to stroke.
The major risk factors for atrial fibrillation include age, coronary artery disease, rheumatic heart disease, hypertension, diabetes, and thyrotoxicosis. Atrial fibrillation affects 7% of the population over 65 years of age, and is also associated with increased risks of congestive heart failure and cardiomyopathy, which warrant medical attention and treatment. Atrial fibrillation is the most common sustained heart rhythm disorder and increases the risk for heart disease and stroke, both leading causes of death in the United States.
To treat cardiac arrhythmias including atrial fibrillation, physicians often employ specialized ablation catheters to gain access into interior regions of the body. Such catheters often include tip electrodes or other ablating elements used to create ablation lesions that physiologically alter the ablated tissue without removal thereof and thereby disrupt or block electrical pathways through the targeted tissue.
In the treatment of cardiac arrhythmias, a specific area of cardiac tissue having aberrant electrically conductive pathways, such as atrial rotors, emitting or conducting erratic electrical impulses, may be initially localized. A physician may direct a catheter through a main vein or artery into the interior region of the heart that is to be treated. The ablating portion of the selected device is next placed near the targeted cardiac tissue that is to be ablated, such as a pulmonary vein ostium or atrium.
An ablation procedure may involve creating a series of inter-connecting lesions, to electrically isolate tissue believed to be the source of an arrhythmia. During such a procedure, a physician may employ several different catheters having variations in geometry and dimensions of the ablative element in order to produce the desired ablation pattern. Multiple devices having varying dimensions and shapes may also be used, to account for variations in anatomy. Each catheter may have a unique geometry for creating a specific lesion pattern or size, with the multiple catheters being sequentially removed and replaced to create the desired multiple lesions.
For example, some catheters may be capable of following a two-dimensional curve, which may be referred to as “curvilinear” or “linear” ablation. Other catheters may be capable of forming a three-dimensional shape, such as a loop that is almost transverse to the catheter's longitudinal axis, which may be referred to as “loop” ablation.
Accordingly, it is desirable to provide a single medical device capable of both linear and loop ablation, thereby reducing the need for additional medical devices.
SUMMARY OF THE INVENTIONThe present invention advantageously provides medical devices, systems, and methods for treating patients with tissue ablation. In particular, catheter systems are provided having bi-modal steering mechanisms, which are capable of both linear and loop ablation. The catheter system may have two different steering modes: two-dimensional and three-dimensional. In the first and second steering modes, the steering actuator may cause one or more portions of the catheter shaft to bend in different planes. A steerable ablation catheter may include treatment elements such as electrodes at its distal end and along the catheter shaft, each of which may map, pace, and ablate. Optional features include a series of thermocouples for monitoring local temperatures.
Methods for ablating a tissue region are also provided, including directing a treatment assembly of a medical device toward a tissue region, and the treatment element may include a series or an array of electrodes; selecting a first or second steering mode; in the first steering mode, manipulating a steering actuator from an initial position to cause a first portion of the catheter body to bend from an initial shape to a first arc shape along a first plane; in the second steering mode, manipulating the steering actuator from the initial position to cause the first portion to bend from the initial shape to a second arc shape, and to cause a second portion of the catheter body to bend along a second plane; and delivering ablative energy to the treatment assembly. The method may also include monitoring an electrical signal of the tissue region, such as a cardiac tissue region, or monitoring temperatures of the electrodes.
A more complete understanding of the present invention, and its associated advantages and features, will be more readily understood by reference to the following description and claims, when considered in conjunction with the accompanying drawings.
In this description, reference will be made to the attached drawings:
The present invention advantageously provides medical devices, systems, and methods for treating patients, in particular with catheter systems having bi-modal steering mechanisms, which are capable of both linear and loop ablation.
Referring to the drawings, the present invention provides various embodiments of medical devices for treating patients, which may be in the form of catheters having more than one steering mode. The illustrations of course depict only some of many different possible catheter designs that are within the scope of the present invention. For clarity and convenience, the present detailed description will only describe a few embodiments.
The catheters of the present invention may be sized and dimensioned for intraluminal and transseptal access to a patient's heart for the treatment or ablation thereof. Some of these embodiments are in the form of catheters generally designated at reference numerals 10 and 12, and catheter shaft designs generally designated at reference numerals 14 and 16.
A first example embodiment of the present invention is shown in
The catheter shaft design of this first example embodiment is shown in
The catheter body may also have at least four portions of alternating higher and lower flexibility 52, 54, 56 and 58. The distal portion of higher flexibility 52 may encompass the treatment assembly 20, for example including all of the electrodes 22, and this portion may be what bends to form the curved shape of the two-dimensional steering mode, and to form the loop of the three-dimensional steering mode. The proximal portion of higher flexibility 56 may encompass bending in the three-dimensional steering mode, to create the desired angle of the loop with respect to the longitudinal axis. In a specific example, the portions of higher flexibility may be polymers having durometers of 30-45 D, and the portions of lower flexibility may be polymers having durometers of 50-72 D.
The catheters of the present invention may have a proximal and distal plane of preferential bending. This compound preferential bending may be achieved with a guide plate 64 as shown in
In operation, the steering actuator 28 may initially be in a neutral position, and the distal catheter shaft will be generally straight (with the possible exception of a curved or concave section of a guide plate), though it will of course tend to follow the shape of any body passage or lumen.
For loop ablation, or at any time three-dimensional steering is desired according to the second steering mode, the steering actuator 28 may be moved or rotated in a second direction to a second position, thus pulling on second steering member 36. In this second steering mode, distal portion 68 of guide plate 64 inside the catheter body's distal portion of higher flexibility 52 will bend in the distal plane of preferential bending, but in the opposite direction as illustrated in
In this three-dimensional steering mode, a distal portion of catheter body may be formed into a loop as shown in
Another example embodiment of a medical device according to the present invention is shown in
This mechanism for selecting different steering modes may be in the form of a movable stiffener 48, shown in
The catheter shaft design of this second example embodiment is shown in
In embodiments having the bi-directional shaft design, the stiffener 48 is coupled at its proximal end with a controller, such as for example slider 32 shown in
Additional optional components for catheter shafts according to the present invention may include reinforcements such as for example a braid or coil embedded in or affixed to the catheter body, which may be made of any suitable material including metals and strong polymers. Specific examples of reinforcing materials may include stainless steel and nitinol. These reinforcing components may also be used to more strongly affix the steering wires to the catheter body, such as for example by embedding them into the wall of catheter body, inside or outside of (or even woven among) reinforcing components.
Another example embodiment of a medical device according to the present invention is shown in
Second steering actuator 82 may be used to bend and steer a more proximal portion of the catheter shaft, to more deftly position the distal assembly near a desired site of tissue for treatment. In catheter shaft designs having at least four alternating portions of higher and lower flexibility, the second steering actuator 82 may enable bending and steering of a supplemental steering portion, which is proximal of the proximal portion of higher flexibility.
Another example embodiment of a medical device according to the present invention is shown in
Now referring to
Each electrode 22 may include a temperature sensor or thermocouple 72 located on or near the tissue side of the electrode, to monitor the temperature at each ablation site before and during ablation. Indeed, each electrode 22 may have a pair of thermocouples at radially or diametrically opposite points. The thermocouples are electrically connected to the handle assembly by conduits or wires, which may optionally be at least partially surrounded by a coil 74 shown in
It should be understood that an unlimited number of configurations for the present invention could be realized. The foregoing discussion describes merely exemplary embodiments illustrating the principles of the present invention, the scope of which is recited in the following claims. In addition, unless otherwise stated, all of the accompanying drawings are not to scale. Those skilled in the art will readily recognize from the description, claims, and drawings that numerous changes and modifications can be made without departing from the spirit and scope of the invention.
Claims
1. A method of medical treatment, the method comprising:
- providing a medical device including a catheter body, at least one steering actuator, and a plurality of treatment elements;
- directing the plurality of treatment elements toward a tissue region;
- selecting one of a first steering mode and a second steering mode: in the first steering mode, manipulating the at least one steering actuator in a first direction from an initial position to cause a first portion of the catheter body to bend from an initial shape to a first arc shape along a first plane; in the second steering mode, manipulating the at least one steering actuator in a second direction from the initial position to cause the first portion to bend from the initial shape to a second arc shape, and to cause a second portion of the catheter body to bend along a second plane; and
- activating the plurality of treatment elements.
2. The method of claim 1, wherein the catheter body has a first portion with a first plane of preferential bending and a second portion with a second plane of preferential bending, the first portion being distal to the second portion.
3. The method of claim 2, wherein the first portion has a higher flexibility than the second portion.
4. The method of claim 1, wherein the medical device further includes a guide plate within the catheter body, the guide plate having a proximal portion, a distal portion, and a transition portion.
5. The method of claim 4, wherein the guide plate distal portion is within the first portion of the catheter body and the guide plate proximal portion is within the second portion of the catheter body.
6. The method of claim 5, wherein, in the first steering mode, the at least one steering actuator is manipulated from the initial position to cause the guide plate distal portion to bend in a first direction in the first plane of preferential bending.
7. The method of claim 6, wherein, in the second steering mode, the at least one steering actuator is manipulated from the initial position to cause:
- the guide plate distal portion to bend in a second direction in the first plane of preferential. bending; and
- the guide plate proximal portion to bend in the second plane of preferential bending.
8. The method of claim 7, wherein the guide plate further has:
- a first outer edge;
- a second outer edge;
- a longitudinal axis;
- a width that extends direction from the first outer edge directly to the second outer edge and that is perpendicular to the longitudinal axis;
- a length that is located along the longitudinal axis; and
- a transition portion between the proximal portion and the distal portion, the proximal portion having: a distal section; a proximal section; and a middle section located directly between the distal section and the proximal section, the middle section having a width that extends directly from the first outer edge of the guide plate directly to the second outer edge of the guide plate.
9. The method of claim 8, wherein:
- the distal section and the proximal section are linear and located along the guide plate longitudinal axis; and
- an entirety of the middle section has an arc of curvature when the catheter body is in an at least substantially linear configuration.
10. The method of claim 5, wherein the medical device further includes a stiffening element longitudinally movable within the catheter body between a proximal position and a distal position.
11. The method of claim 10, further comprising moving the stiffening element to the distal position in the first steering mode.
12. The method of claim 11, wherein the stiffening element is configured to oppose bending of the proximal portion of the guide plate in the first steering mode.
13. The method of claim 11, further comprising moving the stiffening element to the proximal position in the second steering mode.
14. The method of claim 2, wherein the at least one steering actuator includes a first steering actuator and a second steering actuator and the catheter body further has a third portion proximal to the second portion, the method further comprising:
- manipulating the second steering actuator from an initial position to cause the third portion to bend from an initial shape to an arc shape.
15. The method of claim 1, further comprising mapping electrical activity of the tissue region with the plurality of treatment elements.
16. The method of claim 1, wherein the medical device further includes a plurality of thermocouples, the method further comprising monitoring a temperature of each of the plurality of treatment elements with the plurality of thermocouples.
17. A method of medical treatment, the method comprising:
- providing a medical device including: a catheter body, the catheter body having a first portion with a first plane of preferential bending and a second plane of preferential bending, the first portion being distal to and more flexible than the second portion; a steering actuator; a plurality of treatment elements; and a guide plate having a proximal portion, a distal portion, and a transition portion, the guide plate distal portion being within the first portion of the catheter body and the guide plate proximal portion being within the second portion of the catheter body;
- directing the treatment elements toward a tissue region;
- selecting one of a first steering mode and a second steering mode: in the first steering mode, manipulating the at least one steering actuator in a first direction from an initial position to cause the guide plate distal portion to bend in a first direction in the first plane of preferential bending; in the second steering mode, manipulating the at least one steering actuator in a second direction from the initial position to cause the guide plate distal portion to bend from in a second direction in the first plane of preferential bending and to cause the guide plate proximal portion to bend along the second plane of preferential bending;
- directing the plurality of treatment elements such that at least one of the plurality of treatment elements is in contact with the tissue region; and
- activating the plurality of treatment elements.
18. The method of claim 17, wherein the guide plate further has:
- a first outer edge;
- a second outer edge;
- a longitudinal axis;
- a width that extends direction from the first outer edge directly to the second outer edge and that is perpendicular to the longitudinal axis; and
- a length that is located along the longitudinal axis,
- the proximal portion further having: a linear distal section; a linear proximal section; and a middle section located directly between the distal section and the proximal section, the middle section having a width that extends directly from the first outer edge of the guide plate directly to the second outer edge of the guide plate, an entirety of the middle section having an arc of curvature when the catheter body is in an at least substantially linear configuration.
19. The method of claim 17, wherein the medical device further includes a stiffening element longitudinally movable between a proximal position and a distal position, the method further comprising:
- moving the stiffening element to the distal position in the first steering mode; and
- moving the stiffening element to the proximal position in the second steering mode.
20. A method of medical treatment, the method comprising:
- providing a medical device including: a steerable catheter body having a first portion with a first plane of preferential bending and a second portion with a second plane of preferential bending, the first portion being distal of the second portion; a steerable outer sheath at least partially surrounding and being movable with respect to the steerable catheter body; a first steering actuator in mechanical communication with the steerable catheter body; a second steering actuator in mechanical communication with the steerable outer sheath; and a plurality of treatment elements on the steerable catheter body;
- directing the plurality of treatment elements toward a tissue region;
- selecting one of a first steering mode and a second steering mode: in the first steering mode, manipulating the first steering actuator in a first direction from an initial position to cause a first portion of the catheter body to bend from a first shape to a second shape along a first plane; in the second steering mode, manipulating the first steering actuator in a second direction from the initial position to cause the first portion to bend from the first shape to a third shape, and to cause a second portion of the catheter body to bend along a second plane;
- manipulating the second steering actuator from an initial position to cause a portion of the steerable outer sheath to bend from a first shape to a second shape; and
- activating the plurality of treatment elements to ablate the tissue region.
Type: Application
Filed: Aug 19, 2016
Publication Date: Dec 8, 2016
Inventors: Randell WERNETH (San Diego, CA), Ricardo ROMAN (San Diego, CA), Timothy J. CORVI (Carlsbad, CA), Betty HU (La Jolla, CA)
Application Number: 15/241,750