Surgery – Diagnostic testing – Structure of body-contacting electrode or electrode inserted...
Reexamination Certificate
2001-05-24
2004-08-03
Cohen, Lee (Department: 3739)
Surgery
Diagnostic testing
Structure of body-contacting electrode or electrode inserted...
C600S381000, C606S041000
Reexamination Certificate
active
06771996
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates generally to an electrophysiological (“EP”) catheter system for use on biological tissue within a biological site, and more particularly, to a combined mapping and ablating catheter system for use in and around the pulmonary veins.
The heart beat in a healthy human is controlled by the sinoatrial node (“S-A node”) located in the wall of the right atrium. The S-A node generates electrical signal potentials that are transmitted through pathways of conductive heart tissue in the atrium to the atrioventricular node (“A-V node”) which in turn transmits the electrical signals throughout the ventricle by means of the His and Purkinje conductive tissues. Improper growth of, or damage to, the conductive tissue in the heart can interfere with the passage of regular electrical signals from the S-A and A-V nodes. Electrical signal irregularities resulting from such interference can disturb the normal rhythm of the heart and cause an abnormal rhythmic condition referred to as “cardiac arrhythmia.”
Cardiac arrhythmia, including atrial arrhythmia, may be of a multiwavelet reentrant type, characterized by multiple asynchronous loops of electrical impulses that are scattered about the atrial chamber and are often self propagating. In the alternative or in addition to the multiwavelet reentrant type, cardiac arrhythmia may also have a focal origin, such as when an isolated region of tissue in an atrium fires autonomously in a rapid, repetitive fashion.
While there are different treatments for cardiac arrhythmia, including the application of anti-arrhythmia drugs, in many cases ablation of the damaged tissue can restore the correct operation of the heart. Such ablation can be performed by percutaneous ablation, a procedure in which a catheter is percutaneously introduced into the patient and directed through an artery or vein to the atrium or ventricle of the heart to perform single or multiple diagnostic, therapeutic, and/or surgical procedures. In such case, an ablation procedure is used to destroy the tissue causing the arrhythmia in an attempt to remove the electrical signal irregularities or create a conductive tissue block to restore normal heart beat or at least an improved heart beat. Successful ablation of the conductive tissue at the arrhythmia initiation site usually terminates the arrhythmia or at least moderates the heart rhythm to acceptable levels. A widely accepted treatment for arrhythmia involves the application of RF energy to the conductive tissue.
In the case of atrial fibrillation (“AF”), a procedure published by Cox et al. and known as the “Maze procedure” involves the formation of continuous atrial incisions to prevent atrial reentry and to allow sinus impulses to activate the entire myocardium. While this procedure has been found to be successful, it involves an intensely invasive approach. It is more desirable to accomplish the same result as the Maze procedure by use of a less invasive approach, such as through the use of an appropriate EP catheter system providing RF ablation therapy. In this therapy, transmural ablation lesions are formed in the atria to prevent atrial reentry and to allow sinus impulses to activate the entire myocardium.
One such EP catheter system, as disclosed in U.S. Pat. Nos. 6,059,778 and 6,096,036, includes a plurality of spaced apart band electrodes located at the distal-end of the catheter and arranged in a linear array. The band electrodes are positioned proximal heart tissue. RF energy is applied through the electrodes to the heart tissue to produce a series of long linear lesions similar to those produced by the Maze procedure.
As previously mentioned, cardiac arrhythmia, such as atrial fibrillation, may be focal in nature. The foci, defined by regions exhibiting a consistent and centifugal pattern of electrical activation, may act as either a trigger of atrial fibrillation paroxysmal or may even sustain fibrillation. Such focal arrhythmia are known to originate from a tissue region along the pulmonary veins of the left atrium, and more particularly in the superior pulmonary veins.
Procedures for the treatment of focal arrhythmia involving the pulmonary vein generally require the use of two separate catheter systems—a mapping catheter system for locating the foci and an ablation catheter system for ablating the foci. Both catheter systems include their respective mapping or ablation catheter and either a guiding catheter or a guide wire for introducing the catheter into the left atrium of the heart. During a typical procedure, the mapping catheter is first introduced into the left atrium through a puncture in the septum between the right and left atria. The mapping catheter is then guided into the pulmonary vein. While the mapping catheter is still within the heart, the ablation catheter is introduced into the left atrium through either the same puncture as the mapping catheter or a separate puncture. Using the mapping catheter, the foci of the arrhythmia is located using any of several well known mapping techniques. After it is determined that the foci are located within the pulmonary vein, the ablation catheter is positioned either in the pulmonary vein or around the pulmonary vein ostium and the tissue is ablated. The procedure thus described requires the simultaneous placement of two separate catheters into the left atrium through either one or two separate introduction paths. In the case of the left atrium such introduction paths comprise punctures through the atrial septum between the right and left atria. Passing two catheters through a single puncture or two separate punctures increases patient trauma. It also increases the likelihood of damaging the heart through tearing of the septum.
Hence, those skilled in the art have recognized a need for a catheter system having two independent catheters, each capable of being introduced into the heart via a single transseptal introduction path. The need for a combined mapping and ablation catheter system for use in the pulmonary vein has also been recognized. The invention fulfills these needs and others.
SUMMARY OF THE INVENTION
Briefly, and in general terms, the invention is directed to a combination mapping and ablating catheter system for use during electrophysiological procedures in and around various biological sites, including the pulmonary veins.
In a first aspect, the invention relates to a catheter system that includes an outer catheter having a lumen therethrough and a distal-end region carrying a first electrode system. The catheter system also includes an inner catheter that is sized to fit within and slide through the lumen of the outer catheter. The inner catheter has a distal-end region carrying a second electrode system.
By providing an outer catheter having a lumen through which a separate inner catheter may slide, the invention allows for the simultaneous placement of two separate catheters into a biological site through a signal introduction path. As such, the likelihood of damaging the biological site is substantially reduced.
In detailed aspects of the invention, either one or both of the outer catheter and inner catheter further include a tendon having a distal end attached to the distal-end region of the respective catheter and a proximal end exiting the proximal end of the catheter. The tendon is attached such that movement of the tendon along the length of the catheter causes the distal-end region of that catheter to curve. In a another detailed aspect, the outer catheter further comprises a shaped-memory stylet for imparting a preshaped curve to the distal-end region of the outer catheter. In a further detailed aspect, the preshaped curve has a radius of curvature and the catheter further comprises a tendon having a distal end attached to the distal end of the catheter and a proximal end exiting the proximal end of the catheter. The tendon is attached such that movement of the tendon along the length of the catheter decreases the radius of curvature.
In another detailed facet of the invention, the outer catheter
Bowe Wade A.
Hall Jeffrey A.
Cardiac Pacemakers Inc.
Cohen Lee
Fulwider Patton Lee & Utecht LLP
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