| Method and devices for treating atrial fibrillation by mass ablation -> Monitor Keywords |
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Method and devices for treating atrial fibrillation by mass ablationRelated Patent Categories: Surgery, Instruments, Electrical ApplicationMethod and devices for treating atrial fibrillation by mass ablation description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060009756, Method and devices for treating atrial fibrillation by mass ablation. Brief Patent Description - Full Patent Description - Patent Application Claims
RELATED APPLICATIONS [0001] This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 60/571,182 filed on May 14, 2004, which is incorporated herein by reference in its entirety. FIELD OF THE INVENTION [0002] The present invention relates to tools and procedures generally and relates more particularly to the use of ablation to reduce the mass of excitable tissue of the left atrium to prevent and treat atrial fibrillation or other medical conditions. BACKGROUND [0003] Focal triggers initiating atrial fibrillation are thought to frequently arise from the pulmonary veins and their ostia. Surgeons have used the technique of modifying the substrate of the heart in these areas to prevent the propagation of the arrhythmia. In some patients with chronic atrial fibrillation, the Cox/MAZE III procedure has been employed. This procedure controls propagation of the depolarization wavefronts in the right and left atria by means of surgical incisions through the walls of the right and left atria. The incisions create blind or dead end conduction pathways, which prevent re-entrant atrial tachycardias from occurring. [0004] While the Cox/MAZE procedure is successful in treating atrial fibrillation, the procedure is quite complex and is currently practiced by only a few very skilled cardiac surgeons in conjunction with other open-heart procedures. The procedure also is quite traumatic to the heart, as in essence, the right and left atria are cut into pieces and sewed back together, to define lines of lesion across which the depolarization wavefronts will not propagate. Still today, the Cox/MAZE procedure is done with traditional cut and sew techniques. [0005] The market is demanding quicker, safer and less invasive approaches. As a result, there has been much recent research and evaluation of mechanisms to encircle and isolate the pulmonary veins and replicate the incisions of the MAE operation. Companies are developing ablation techniques that heat (or cool) or chemically destroy the underlying tissue along these lines. [0006] It has been suggested that procedures similar to the MAZE procedure could be instead, performed by means of electrosurgical ablation, for example, by applying radio frequency energy to internal or external surfaces of the atria to create lesions across which the depolarization wavefronts will not propagate. Such procedures are disclosed in U.S. Pat. No. 5,895,417, issued to Pomeranz, et al. ("the Pomeranz '417 patent"); U.S. Pat. No. 5,575,766, issued to Swartz, et al. ("the Swartz '766 patent"); U.S. Pat. No. 6,032,077, issued to Pomeranz ("the Pomeranz '077 patent"); U.S. Pat. No. 6,142,994, issued to Swanson, et al. ("the Swanson '994 patent"); and U.S. Pat. No. 5,871,523, issued to Fleischman, et al. ("the Fleischman '523 patent"), all incorporated herein by reference in their entireties. [0007] The Pomeranz '417 patent discloses an apparatus for ablating tissue by making linear lesions within the chamber of a patient's heart by application of a plurality of spaced electrodes along an elongate member. The Schwartz '766 patent discloses a process for treating atrial arrhythmia by creating discrete ablation tracks within both the left and right atrium. The Pomeranz '077 patent discloses an ablation catheter that is electrically connected to tissue to be ablated by a foam on the electrodes that is soaked in saline. The foam in the Pomeranz '077 patent acts as a conductive fluid to allow energy from the electrode to ablate the contacted tissue. The Swanson '994 patent discloses a surgical method and apparatus for positioning an element in the body of a patient for diagnosis or therapy. The apparatus in the Swanson '994 patent may be a catheter or a probe having a shaft with a lumen extending there through. The Fleischman '523 patent discloses a helically-wound emitter on an element with a insulating sheath movable over the emitter. [0008] Various types of electrophysiology devices are used for ablating tissue. Typically, such devices include a conductive tip or blade that serves as one electrode in an electrical circuit that is completed via a grounding electrode coupled to the patient. The contact point is small or linear to create lesions to form linear tracks of ablated tissue. A power source creates high levels of electrical energy between the two electrodes causing the tissue to heat to a sufficient level to denature proteins within the tissue and cause cell death. In order for such procedures to be effective, it is desirable that the electrosurgically-created lesions are continuous along their length and extend completely through the tissue of the heart. [0009] Manufacturers have developed catheters that have a linear array of electrodes along a long axis (e.g., the Amazr, MECCA, and Revelation catheters). The surgeon positions the catheter and electrodes in contact with the tissue and either individually or sequentially applies energy to each electrode. Additionally, catheters that incorporate an electrode that is energized and moves along its length have been proposed, such as the Flex-10 from AFx, Inc., of 47929 Fremont Aye, Fremont, Calif. 94538. [0010] Surgeons have also been able to create linear lesions on the heart using applications of the same techniques. For example, Kottkamp, et. al. in an article entitled "Intraoperative Radio Frequency Ablation of Chronic Atrial Fibrillation: A Left Atrial Curative Approach by Elimination of Anatomic `Anchor` Reentrant Circuits," Journal of Cardiovascular Electrophysiology, 10:772-780 (1999), describe a hand-held device that creates as series of spot or short (less than 1 cm) linear lesions. Other investigators have used long, linear unipolar probes to create somewhat longer lesions. Still others have used multi-electrode linear catheters, similar to those described above to create a series of ablations that net a linear lesion. [0011] The focus of most investigators has been to isolate the pulmonary veins. There is growing research that suggests this may not be necessary in the prevention and cure of atrial fibrillation, as discussed in the article by G. Stabile, P. Turco, V. La Rocca, P. Nocerino, E. Stabile, and A. Dc Simone entitled "Is Pulmonary Vein Isolation Necessary for Curing Atrial Fibrillation?," Circulation, 108:657-660 (2003). Rather than focusing on only isolating the pulmonary veins, reduction in the overall volume of excitable tissue in the left atrium is sufficient to prevent atrial fibrillation. The general concept is to ablate a large enough nonlinear area of the left atrium to prevent re-entrant waves and the propagation of atrial fibrillation. SUMMARY OF THE INVENTION [0012] Some embodiments of the invention provide a method of ablating target tissue including a non-linear area of tissue in the left atrium of a patient. The method can include selecting an ablation apparatus having an ablator or ablation member with a tissue engagement section, penetrating a chest cavity of the patient, and identifying the target tissue. The method can also include positioning the ablation apparatus adjacent to the target tissue so that the tissue engagement section can transfer ablation energy to the target tissue. The method can further include energizing the tissue engagement section with ablation energy in order to create a footprint on the non-linear area of tissue in the left atrium and to reduce an overall mass of excitable tissue in the left atrium. [0013] In some embodiments, an ablation apparatus can include an insertion tool having a proximal end, a distal end, and a lumen. The ablation apparatus can include an ablator or ablation member having a conductor and a tissue engagement portion. The conductor can include a source end extending from the proximal end of the insertion tool and a delivery end coupled to the tissue engagement portion. The ablator can be removably inserted in the lumen. The ablation apparatus can also include an energy source connected to the conductor. The insertion tool can be inserted into a patient so that the distal end is adjacent the target tissue. The conductor can urge the ablator out of the lumen to engage the target tissue. Energy can be conducted from the energy source to the ablator to create a footprint on the target tissue to reduce an overall mass of excitable tissue. BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 is an illustration of a posteroinferior view of the human heart removed from the chest cavity. [0015] FIG. 2 is an illustration of a cross-section of the human heart showing the left atrium and the ostia leading to the pulmonary veins. [0016] FIG. 3 is a schematic illustration of an ablation apparatus according to one embodiment of the invention shown being applied to a patient. [0017] FIG. 4 is a top view of an ablation apparatus according to another embodiment of the invention with an ablator on an insulated balloon. [0018] FIG. 4A is a cross-sectional view along the line 4A-4A of FIG. 4. [0019] FIG. 4B is a partial perspective view of a distal end of an insertion tool having the ablator of FIG. 4 removably inserted therein. Continue reading about Method and devices for treating atrial fibrillation by mass ablation... Full patent description for Method and devices for treating atrial fibrillation by mass ablation Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method and devices for treating atrial fibrillation by mass ablation patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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