Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical energy applicator
Reexamination Certificate
2001-09-06
2004-04-06
Schaetzle, Kennedy (Department: 3762)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical energy applicator
Reexamination Certificate
active
06718211
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to pacing and defibrillation medical electrical leads. The present invention also relates to medical electrical 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 Gap 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.
Medical electrical leads suitable for implantation within the right atrium and/or right the ventricle are known in the art. Leads having J-shapes imparted to the distal ends thereof are likewise known in the art. Such leads having J-shaped distal ends typically exhibit substantial bending stiffness at the distal thereof, and are most often configured for placement in the right atrium. It is typical that during implantation of such a lead having a J-shaped section at the distal end thereof that, once the lead has been placed within the right atrium, the lead is retracted slightly to impart a positive tip force to the distal end of the lead. Relatively small displacements of the lead in such a manner can result in large variations in the force exerted by the tip of the lead upon the atrial wall. It is therefore not uncommon for the force exerted by the tip to either be excessive or to even become negative, in which event the distal end of the lead is suspended from its own tines or other distally disposed positive fixation device. This, in turn, leads to mechanical instability of the positioning of the distal section of the lead within the right atrium or the right ventricle.
Thus, there exists a need to provide a pacing or defibrillation medical electrical lead which exhibits better mechanical stability following implantation.
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 right atrium or right ventricle which is not mechanically unstable once implanted therein; (b) providing a medical electrical lead which exhibits enhanced removability following implantation and fibrosis; (c) providing a medical electrical lead suitable for implantation within the right atrium or right ventricle which requires less time and effort to implant; (d) providing a medical electrical lead which exhibits reduced overall stiffness at the distal end thereof; (e) providing a medical electrical lead, the implantation of which exhibits decreased dependency on the longitudinal position of the lead body thereof in the veins leading to the right atrium or right ventricle; (f) a medical electrical lead wherein small dislodgments occurring near the entrance of the lead in the vein near the anchoring sleeve do not lead to electrode tip dislodgment; and (g) a medical electric
Droesch Kristen
Medtronic Inc.
Schaetzle Kennedy
Wolde-Michael Sirma
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