Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical energy applicator
Reexamination Certificate
2001-09-06
2004-05-25
Schaetzle, Kennedy (Department: 3762)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical energy applicator
Reexamination Certificate
active
06741893
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to pacing and defibrillation medical electrical leads. The present invention also relates to such leads adapted and configured for implantation within the coronary sinus and coronary veins.
BACKGROUND OF THE INVENTION
Transvenously inserted leads for implantable cardiac pacemakers have conventionally been positioned within the right atrium or right ventricle of the patient's heart for pacing or defibrillating the right atrium and/or right ventricle, respectively. While it is relatively safe to insert a pacing or defibrillation lead and its associated electrodes into the right atrium or right ventricle, there is a reluctance to install a similar lead in the left ventricle because of the possibility of clot formation and resulting stroke.
When a lead is implanted within a patient's circulatory system, there is always the possibility of a thrombus being generated and released. If the lead is positioned in the right atrium or right ventricle, a generated thrombus tends to migrate through the pulmonary artery and is filtered by the patient's lungs. A thrombus generated in the left atrium or left ventricle, however, would pose a danger to the patient due to the possibility of a resulting ischemic episode.
Thus, in those instances where left heart stimulation is desired, it has been a common practice to use an intercostal approach using a myocardial screw-in, positive-fixation lead. The screw-in lead may, however, be traumatic for the patient. There are additional instances when left ventricular pacing is desired, such as during bi-ventricular pacing. In U.S. Pat. No. 4,928,688, Mower describes an arrangement for achieving bi-ventricular pacing in which electrical stimulating pulses are applied via electrodes disposed on a single pacing lead to both the right and left ventricular chambers so as to obtain a coordinated contraction and pumping action of the heart. The '688 patent also discloses a split pacing lead having first and second separate electrodes, wherein the first electrode is preferably introduced through the superior vena cava for pacing the right ventricle and the second electrode is introduced through the coronary sinus for pacing the left ventricle. Other electrode leads which are inserted into the coronary sinus have been described. For example, in U.S. Pat. No. 5,014,696 to Mehra and U.S. Pat. No. 4,932,407 to Williams endocardial defibrillation electrode systems are disclosed.
Still other leads and catheters have been proposed, including those described in the patents listed in Table 1 below.
TABLE 1
U.S. Pat. No.
Title
5,951,597
Coronary sinus lead having expandable matrix anchor
5,935,160
Left ventricular access lead for heart failure pacing
5,931,864
Coronary venous lead having fixation mechanism
5,931,819
Guidewire with a variable stiffness distal portion
5,925,073
Intravenous cardiac lead with wave shaped fixation
segment
5,897,584
Torque transfer device for temporary transvenous
endocardial lead
5,871,531
Medical electrical lead having tapered spiral fixation
5,855,560
Catheter tip assembly
5,833,604
Variable stiffness electrophysiology catheter
5,810,867
Dilation catheter with varied stiffness
5,803,928
Side access “over the wire” pacing lead
5,755,766
Open-ended intravenous cardiac lead
5,755,765
Pacing lead having detachable positioning member
5,749,849
Variable stiffness balloon catheter
5,733,496
Electron beam irradiation of catheters to enhance
stiffness
5,639,276
Device for use in right ventricular placement and method
for using same
5,628,778
Single pass medical electrical lead
5,605,162
Method for using a variable stiffness guidewire
5,531,685
Steerable variable stiffness device
5,499,973
Variable stiffness balloon dilatation catheters
5,437,632
Variable stiffness balloon catheter
5,423,772
Coronary sinus catheter
5,330,521
Low resistance implantable electrical leads
5,308,342
Variable stiffness catheter
5,144,960
Transvenous defibrillator lead and method of use
5,111,811
Cardioversion and defibrillation lead system with
electrode extension into the Coronary sinus and
great vein
4,930,521
Variable stiffness esophageal catheter
4,215,703
Variable stiffness guide wire
08/794,175
Single Pass Medical Electrical Lead
08/794,402
Single Pass Medical Electrical Lead with Cap Electrodes
As those skilled in the art will appreciate after having reviewed the specification and drawings hereof, at least some of the devices and methods discussed in the patents of Table 1 may be modified advantageously in accordance with the present invention. All patents listed in Table 1 herein above are hereby incorporated by reference herein, each in its respective entirety.
Prior art coronary vein leads for heart failure applications (i.e., pacing leads) or sudden death applications (i.e., defibrillation leads) generally must be wedged in a coronary vein to obtain a stable mechanical position and to prevent dislodgment. While such an arrangement is generally acceptable for defibrillation leads (which usually must be implanted with the distal tip thereof located near the apex of the heart), such is not the case for heart failure or pacing leads, where more basal stimulation of the heart is generally desired. Basal stimulation of the heart via the coronary vein, however, presents certain difficulties because vein diameters in the basal area of the heart are large and generally do not permit the distal end or tip of a pacing lead to be sufficiently well wedged therein.
Thus, there exits a need to provide a pacing or defibrillation medical electrical lead which is capable of being implanted within both larger diameter and smaller diameter portions of the coronary vein anatomy of a human heart where the lead does not require lead tip wedging. There is also a need to provide a medical electrical lead for pacing and defibrillation applications in which the orientation of an electrode mounted on a distal portion thereof may be controlled and adjusted to permit the electrode to point towards the left ventricular myocardium or other selected portions of the heart accessible via the coronary vein anatomy to thereby minimize pacing thresholds and improve sensing. There is a further need to provide a medical electrical lead for pacing and defibrillation applications in which the orientation of a pacing or defibrillation electrode disposed on a distal portion thereof may be determined using conventional x-ray or echo/acoustic techniques.
SUMMARY OF THE INVENTION
The present invention has certain objects. That is, the present invention provides solutions to one or more problems existing in the prior art. For example, various embodiments of the present invention have one or more of the following objects: (a) providing a medical electrical lead suitable for implantation in the coronary sinus or coronary vein which is not pushed out of the coronary sinus or coronary vein once implanted therein; (b) providing a medical electrical lead suitable for implantation within relatively large diameter portions of the coronary sinus and coronary vein without requiring wedging or the use of positive fixation means such as tines, helical screws or the like; (c) providing a medical electrical lead which exhibits enhanced removability following implantation and fibrosis; and (d) providing a medical electrical lead suitable for implantation within the coronary sinus or coronary veins which requires less time and effort to implant.
Various embodiments of the present invention suitable for implantation within the coronary sinus or coronary veins possess certain advantages, including one or more of the following: (a) exhibiting multiple lead mechanical stability points which are not dependent on any positive fixation mechanisms such as wedging, hooking, screwing or clamping; (b) providing a lead whose retention within the coronary veins is less dependent upon the particular shape or diameter of such veins than prior art leads; (c) providing a lead which permits improved pacing electrode positioning within the coronary venous anatomy; (d) prov
Droesch Kristen
Medtronic Inc.
Wolde-Michael Girma
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