Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2001-02-28
2004-04-06
Casler, Brian L. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S174000, C604S500000, C604S506000, C604S523000, C604S264000
Reexamination Certificate
active
06716196
ABSTRACT:
BACKGROUND OF THE INVENTION
Abnormal heart beats or cardiac arrhythmias can cause significant morbidity and mortality. These arrhythmias arise from a variety of causes, including atherosclerotic heart disease, ischemic heart disease, metabolic or hemodynamic derangements, rheumatic heart disease, cardiac valve disease, certain pulmonary disorders and congenital etiologies. The normal heart rate is about 60 to 100 beats per minute. Arrhythmias refer to tachycardias at rates exceeding 100 beats per minute for a duration of at least 3 beats. Sometimes no treatment is required, such as in the tachycardia following a physiologic response to stress or exercise. However, in some cases, treatment is required to alleviate symptoms or to prolong the patient's life expectancy.
A variety of treatment modalities exist, including electric direct current cardioversion, pharmacologic therapy with drugs such as quinidine, digitalis, and lidocaine, treatment of an underlying disorder such as a metabolic derangement, and ablation by either percutaneous (closed chest) or surgical (open chest) procedures. Treatment by ablation involves destruction of a portion of cardiac tissue which is functioning abnormally electrically.
Normally the heart possesses an intrinsic pacemaker function in the sinoatrial (SA) node which is in the right atrium, adjacent to the entrance of the superior vena cava. The right atrium is one of four anatomic chambers of the heart. The other chambers are the right ventricle, the left atrium, and the left ventricle. The superior vena cava is a major source of venous return to the heart. The SA node is an area of specialized cardiac tissue called Purkinje cells and which usually measures roughly III centimeters by about 2k millimeters. An electrical impulse normally exits from the SA node and travels across the atrium until it reaches the atrioventricular (AV) node. The AV node is located in the right atrium near the ventricle.
Emerging from the AV node is a specialized bundle of cardiac muscle calls which originate at the AV node in the interatrial septum. This “bundle of His” passes through the atrioventricular junction and later divides into left and right branches which supply the left and right ventricles. The left and right bundles further give rise to branches which become the so-called distal His-Purkinje system which extends throughout both ventricles.
Thus in a normal situation an impulse originates intrinsically at the SA node, transmits through the atrium and is modified by the AV node. The AV node passes the modified impulse throughout the left and right ventricles via the His-Purkinje system to result in a coordinated heartbeat at a normal rate.
Many factors affect the heart rate in addition to the intrinsic conduction system. For example, normally the heart rate will respond to physiologic parameters such as stress, exercise, oxygen tension and vagal influences. Additionally, there are multiple causes for an abnormal heartbeat such as an abnormal tachycardia. One group of such causes relates to abnormalities in the hearts conduction system. For example, ectopic or abnormally positioned nodes may take over the normal function of a node such as the SA or AV node. Additionally, one of the normal nodes may be diseased such as from ischemic heart disease, coronary artery disease or congenital reasons. Similarly, a defect can exist in an important part of the conduction system such as the bundle of His or one of the bundle branches supplying the ventricles.
Treatment of abnormal tachycardias arising from ectopic foci or so-called ectopic pacemakers can include pharmacologic therapy or ablative therapy. The ablative therapy may be accomplished by percutaneous insertion of a catheter or by an open surgical cardiac procedure.
Cardiac arrhythmias may be abolished by ablating the tissue responsible for the genesis and perpetuation of the arrhythmias. Steerable ablation catheters using radio frequency (RF) energy are known. The RF energy can be directed to the area to be ablated and causes destruction of tissue by heat. In addition, direct infusion of ethanol has been performed during open heart surgery. Ethanol has also been infused into coronary arteries to ablate a focus such as a ventricular arrhythmia focus or the AV node. Unfortunately this tends to result in a fairly large region of cardiac tissue death or myocardial infarction. With transarterial infusion there is difficulty in precisely controlling the location and extent of the ablation.
Thus, the prior art lacks catheters useful for direct endocardial infusion of sclerosing agents at the precise location of tachycardia. The present invention addresses these and other needs.
SUMMARY OF THE INVENTION
The present invention is directed to methods and devices for delivery of desired compounds (e.g., ablation liquids) to cardiac and other tissue using a novel hollow infusion needle. The needle is typically used to inject an ablation liquid endocardially to produce a more circumscribed lesion than that possible using prior art infusion techniques. The needle is designed such that it can be imbedded in and secured to the tissue to be treated.
Although ablation of cardiac tissue is a preferred use of the catheters of the invention, they can be used to inject desired compositions for a wide variety of uses. Virtually any therapeutic compound can be delivered intracardially using the catheters of the invention. For instance, the catheters can be used to deliver compositions comprising modified genes to cardiac or other tissue for use in gene therapy protocols. Methods for introducing a variety of desired polynucleotides to target cells using, for example, retroviral vectors are well known. Examples of sequences that may be introduced-include antisense polynucleotides to control expression of target endogenous genes. In addition, genes encoding toxins can be targeted for delivery to cancer cells in tumors. In other embodiments, homologous targeting constructs can be used to replace an endogenous target gene. Methods and materials for preparing such constructs are known by those of skill in the art and are described in various references. See, e.g., Capecchi, Science 244:1288 (1989). Examples of deliverable materials include: polynucleotides selected from the group consisting of DNA, RNA, a viral vector, and a non-viral vector; therapeutic compounds selected from the group consisting of peptides and polypeptide; therapeutic compounds selected from the group consisting of immunogenic proteins, exogenous proteins and growth factors; and therapeutic compounds selected from the group consisting of cells, isolated cells, and cell substitutes.
Other uses include intramyocardial delivery of isolated cells or cell substitutes. These approaches typically involve placement of the desired cells on or within matrices or membranes which prevent the host immune system from attacking the calls but allow nutrients and waste to pass to and from the calls (see, Langer et al., Science 260:920-925 (1993)). For instance, sinus node cells can be implanted in a desired location to treat disorders in impulse formation and/or transmission that lead to bradycardia.
For use in ablation of cardiac tissue, the catheters of the invention have an elongated flexible body and a tissue ablation assembly having a tissue ablation tip, at the distal end of the body. The distal end of the catheter is introduced into a cardiac chamber (or other body region) including the tissue to be ablated. The catheter may be equipped for standard arrhythmia mapping, for example multiple electrodes may be present on the outside of the catheter for recording endocardial electrograms. Alternatively, the catheter may include a visualization assembly at the distal end of the body. The visualization assembly is used to position the tip of the catheter adjacent the tissue to be ablated. Catheters comprising visualization and ablation means are described in copending application, Attorney Docket No. 2307F-449, which is incorporated herein by reference.
The tissue ablation assembl
Edwards Stuart D.
Kordis Thomas F.
Lesh Michael D.
Casler Brian L.
Morrison & Foerster / LLP
Rodriguez Cris L.
The Regents of the University of California
LandOfFree
Catheter system for delivery of Therapeutic compounds to... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Catheter system for delivery of Therapeutic compounds to..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Catheter system for delivery of Therapeutic compounds to... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3186375