Atrial ablation catheter adapted for treatment of septal wall arrhythmogenic foci and method of use
An atrial ablation catheter with an electrode array particularly adapted to locate and ablate foci of arrhythmia which are required for sustained atrial fibrillation is provided. The array is easily deployed and retracted from the catheter, and presents a proximally oriented electrode array that can be pulled against the septal wall of the left atrium to engage the septal wall.
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This application is a continuation-in-part of U.S. patent application Ser. No. 10/997,713 filed Nov. 24, 2004.
FIELD OF THE INVENTIONSThe inventions described below relate the field of atrial ablation.
BACKGROUND OF THE INVENTIONSAtrial fibrillation is a form of arrhythmia, or irregular heartbeat, in which the atria (the two small upper chambers of the heart) quiver instead of beating effectively. While there are a number of variations of atrial fibrillation with different causes, they all involve irregularities in the transmission of electrical impulses through the heart. As a result of abnormalities in the heart's electrical impulses, the heart is not able to pump the blood out properly, and it may pool and clot. If a blood clot moves to an artery in the brain, AF can lead to stroke. AF is also associated with increased risks of congestive heart failure and cardiomyopathy. These risks warrant medical attention for patients with AF even if the symptoms are mild. 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. Over 2 million adults in the United States have been diagnosed with atrial fibrillation.
Various ablation techniques have been proposed to treat atrial fibrillation, including the Cox-Maze procedure, linear ablation of various regions of the atrium, and circumferential pulmonary vein ablation. Each of these techniques has its various drawbacks. The Cox-Maze procedure and linear ablation procedures are tedious and time-consuming, taking up to several hours to accomplish endocardially. Circumferential ablation is proving to lead to rapid stenosis and occlusion of the pulmonary veins, and of course is not applicable to treatment of the septal wall of the left atrium. The catheter mounted electrode arrays described in our co-pending patent application Kunis, et al., Atrial Ablation Catheter and Method of Use, U.S. application Ser. No. 10/997,172 filed Nov. 24, 2004 provide for more efficient and effective treatment of atrial fibrillation. The treatment of the septal wall is facilitated with the devices and methods described below, which permit septal wall treatment from a percutaneous venous access route without the need to maneuver a distally facing electrode array in apposition to the septal wall.
SUMMARYThe devices and methods described below provide for a simplified approach to the treatment of atrial fibrillation with substantially improved efficacy and outcomes in patients with paroxysmal or persistent atrial fibrillation, especially for those arrhythmia originating from, or sustained by, arrhythmogenic foci located on the septal wall of the left atrium. An endocardial catheter with an electrode array particularly adapted to locate and ablate foci of arrhythmia which are required for sustained atrial fibrillation is provided. The array is easily deployed and retracted from the catheter, and presents a proximally oriented electrode array that can be pulled against the septal wall of the left atrium to engage the septal wall. A control system comprising an ECG analyzer and a RF power supply operates to analyze electrical signals obtained from the electrode array, determine if an arrhythmogenic focus is present in the area covered by the array, and supply RF power to appropriate electrodes to ablate the focus.
BRIEF DESCRIPTION OF THE DRAWINGS
To accomplish ablation of the septal wall of the left atrium, a catheter is inserted into the atrium, preferably through the inferior vena cava 20, as shown in the illustration, or through the superior vena cava 21, into the right atrium and then into left atrium. When passing into the left atrium, as illustrated, the catheter penetrates the fossa ovalis (a trans-septal puncture will facilitate the crossing). The catheter 22 carries a distal electrode array 23 into the atrium, and this electrode array is adapted to be pulled into contact with the section of the atrial wall surrounding the fossa ovalis. The electrode array is electrically connected to circuitry in a control system 24 which is operable to analyze electrical signals detected by the electrodes and pass RF current through the electrodes and heart tissue to ablate the tissue. A surface electrode 25 is mounted on the patient's body (typically on the back) to permit use of the electrodes in monopolar modes. A return electrode 26 may also be provided on the catheter 22, proximal to the electrode array. Using the catheter, an electrophysiologist will map regions of the septal wall of the left atrium and apply energy through the catheter to ablate any arrhythmogenic foci which are identified in the mapping procedure. The procedure may be repeated as necessary on the septal wall, rotating the array if necessary, to ablate all detected foci.
The electrode array includes a number electrodes 40 mounted on the proximal section 42 of each array arm, and the distal section 41 need not have any electrodes disposed on it, as is shown. The overall shape of each arm is elongate on an axis perpendicular to the long axis of the catheter, having a radial length R which is several times the axial length A.
The resilient expansion of the electrode array pushes the floating tube 44 proximally into the inner catheter tube. When the outer catheter tube is pushed distally over the electrode array, the distal electrode arms will be forced distally, as the proximal segments are compressed inwardly starting from the proximal end, to first splay the distal segments toward and through a perpendicular relationship with the floating tube such that the joint between the arms and the floating tube is distal to the bend point, while drawing the floating tube distally within the inner catheter tube.
After contact has been established between the atrium wall and the electrode array, the operator will analyze electrical signals detected by the electrodes to determine if the array has been placed over an arrhythmogenic focus. If it has, the operator may energize any of the electrodes, as appropriate, to ablate the focus. Bipolar RF energy may be applied between pairs of the electrodes, or monopolar energy may be applied to any of the electrodes (grounded to the surface electrode or a return electrode located proximally on the catheter body). The array may moved off the septal wall, rotated slightly, and reseated against the septal wall to test and treat the entire area surrounding the fossa ovalis with just a few array arms (alternatively, the array may be provided with many arms, such that the electrode density it sufficient to find an ablate all significant foci within its footprint). Linear lesions may be created using the electrodes along a single proximal arm, operating the electrodes in bipolar mode, and other therapeutic lesions may be created using electrodes pairs established between the electrodes of one arm and the electrodes of another arm, operating such pairs in bipolar mode, or operating electrodes in conjunction with return electrodes in a monopolar mode.
While the preferred embodiments of the devices and methods have been described in reference to the environment in which they were developed, they are merely illustrative of the principles of the inventions. Other embodiments and configurations may be devised without departing from the spirit of the inventions and the scope of the appended claims.
Claims
1. An ablation catheter comprising:
- a catheter having a distal end adapted for insertion into the left atrium of a patient;
- an electrode array comprising at least one resilient arm, each arm having a proximal arm segment and a distal arm segment extending distally from an outer end of the proximal arm toward the center line of the catheter; and
- a plurality of electrodes disposed on each of the proximal arm segments of the array;
- wherein the proximal arms are arcuate, and extend outwardly and proximally and then curve distally from their attachment point to catheter.
2. An ablation catheter of claim 1 wherein the proximal arm segments are curved in a cordate arc.
3. An ablation catheter of claim 1 wherein the proximal arm segment is curved in a hastate arc.
4. An ablation catheter of claim 1 wherein the proximal arm segment and distal arm segment define a sagittate lobe.
5. An ablation catheter of claim 1 wherein each distal arm segment is characterize by a proximal end and a distal end;
- further comprising a proximally extending pin fixed at the distal end of the distal arm and extending into the catheter, said pin being longitudinally slidable relative to the catheter:
6. An ablation catheter of claim 1 further comprising:
- a plurality of resilient arms on the array, wherein each of the plurality of arms is substantially the same size and shape, and the resilient arms are uniformly distributed radially about the axis of the catheter.
7. An ablation catheter of claim 1 further comprising:
- a plurality of resilient arms on the array, wherein at least one of the plurality of resilient arms is substantially different in size or shape than other arms in the array.
8. An ablation catheter of claim 1 further comprising:
- a plurality of resilient arms on the array unevenly distributed such that several arms are concentrated in a small radial section about the axis of the catheter, and a significant radial section is vacant.
9. An ablation catheter comprising:
- an outer catheter tube;
- an inner catheter tube slidably disposed within the outer catheter tube, said inner catheter tube having a distal end adapted for insertion into a vessel of the body;
- an electrode array comprising a plurality of resilient arms, each arm having a proximal arm segment fixed to the inner catheter tube and a distal arm segment extending distally from an outer end of the proximal arm;
- a plurality of electrodes disposed on each of the proximal arm segments of the array;
- means for fixing the distal end of the electrode arms in a radially central area while leaving the distal ends of the electrode arms freely translatable along the catheter longitudinal axis
- wherein the proximal arm segments are curved in cordate arc.
10. An ablation catheter comprising:
- an outer catheter tube;
- an inner catheter tube slidably disposed within the outer catheter tube, said inner catheter tube having a distal end adapted for insertion into a vessel of the body;
- an electrode array comprising a plurality of resilient arms, each arm having a proximal arm segment fixed to the inner catheter tube and a distal arm segment having proximally tending extension extending proximally from the distal end of the distal arm segment, said extension being longitudinally translatable within the inner catheter tube, whereby the electrode array may be compressed by longitudinal translation of the outer catheter tube relative to the inner catheter tube, and the proximally tending extension longitudinally translates relative to the inner tube to accommodate longitudinal movement of the distal end of the resilient arms in response to compression of the electrode array;
- an electrode array comprising a plurality of resilient arms, each arm having a proximal arm segment fixed to the inner catheter tube and a distal arm segment extending distally from an outer end of the proximal arm;
- a plurality of electrodes disposed on each of the proximal arm segments of the array;
- means for fixing the distal end of the electrode arms in a radially central area while leaving the distal ends of the electrode arms freely translatable along the catheter longitudinal axis
11. The ablation catheter of claim 10, wherein:
- the floating tube is disposed at least partially within the distal end of the inner catheter tube.
12. The ablation catheter of claim 10, wherein:
- the electrode array is resiliently movable from a small diameter configuration to a large diameter configuration, and in the large diameter configuration each proximal arm segment resiliently bends radially outwardly from the inner catheter tube, and each distal arm segment bends radially inwardly toward the longitudinal axis of the catheter from a bend point connecting the proximal arm segment to the distal arm segment, creating an acute angle between each distal arm segment and its associated proximal arm segment.
13. The ablation catheter of claim 10, wherein:
- the electrode array is resiliently movable from a small diameter configuration and a large diameter configuration, and in the large diameter configuration each proximal arm segment resiliently bends radially outwardly from the inner catheter tube, and each distal arm segment bends radially inwardly and proximally toward the longitudinal axis of the catheter from a bend point connecting the proximal arm segment to the distal arm segment.
14. The ablation catheter of claim 10, wherein:
- the electrode array is resiliently movable from a small diameter configuration and a large diameter configuration, and in the large diameter configuration each proximal arm segment resiliently bends radially outwardly from the inner catheter tube, and each distal arm segment bends radially inwardly and proximally toward the longitudinal axis of the catheter from a bend point connecting the proximal arm segment to the distal arm segment, and said electrode arms are further deformable upon pressing the array against a surface to position the distal arm segments into a substantially planar arrangement.
15. The ablation catheter of claim 14 in the small diameter configuration, the distal arm segments are restrained within a segment of the outer catheter tube which is distal to the proximal arm segments, and extend distally from the bend point.
16. The ablation catheter of claim 14 wherein, in the small diameter configuration, the distal arm segments are folded inwardly so as to be disposed proximate the proximal arm segments and extend proximally from the bend point.
Type: Application
Filed: Apr 15, 2005
Publication Date: May 25, 2006
Applicant:
Inventors: Hakan Oral (Ann Arbor, MI), Randell Werneth (San Diego, CA), Thomas Castellano (Temecula, CA), Christopher Kunis (San Diego, CA)
Application Number: 11/107,190
International Classification: A61B 18/14 (20060101);