Pacing lead with x-ray visible soluble covering and method of inserting same into a patient's heart

• US 5,531,783 A
• Filed: 01/17/1995
• Issued: 07/02/1996
• Est. Priority Date: 01/17/1995
• Status: Expired due to Term

• Current Assignee: Vitatron Medical BV (Medtronic Plc)
• Original Assignee: Vitatron Medical BV (Medtronic Plc)
• Inventors: Giele, Vincent, Berkhof, Marc
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US08/372,971
• Time in Patent Office: 532 Days
• Field of Search: 607/116, 607/120, 607/122, 607/126, 607/127, 607/128, 607/130, 607/131, 128/642
• US Class Current: 607/126
• CPC Class Codes: A61N 1/0573 chacterised by means penetrating the heart tissue, e.g. helix needle or hook

Abstract

A body implantable lead is provided, suitably a pacing lead for delivering pacing stimulus pulses to a patient, the lead having a fixation element such as a helix at its distal tip. The lead is provided with a soluble covering over the helix, which covering presents a smooth surface during insertion of the lead transvenously and dissolves away after a predetermined time in the patient'"'"'s body, thereby exposing the anchor element. The lead is further improved by combining a radiopaque or angiographic contrast material with the protective coating, so that the physician carrying out the implantation procedure can monitor and see exactly when the coating has dissolved, whereupon the fixation element can be directly attached to the patient'"'"'s heart wall.

Claims

1. An implantable lead having a distal end and an electrode near said distal end, a proximal end, a flexible length between said distal and proximal ends, and a conductor connecting said proximal end and said electrode, said lead having a fixation element at about said distal end for effecting fixation to body tissue at a selected location in a patient, and a covering over at least a portion of said fixation element to facilitate insertion of said lead to a point where said fixation element is proximate to said location, said covering being soluble in body fluids and having dissolving characteristics selected so that it dissolves only after being in said body fluids for at least a predetermined time, whereby said covering maintains its structural integrity for at least said predetermined time after being inserted into the patient, said covering having a radiopaque material within at least a portion thereof to provide an x-ray visible target until said covering dissolves but not thereafter, whereby it can be determined when said covering has dissolved by monitoring said lead distal end with x-ray equipment.

2. The implantable lead as described in claim 1, wherein said lead is a pacing lead having a connecting element at its proximal end for connection to a pacemaker, and wherein said covering has radiopaque material mixed within at least a portion thereof.

3. The lead as described in claim 1, wherein said fixation element is a helix.

4. The lead as described in claim 1, wherein the entire said covering is substantially uniformly mixed with said radiopaque material.

5. The lead as described in claim 1, wherein said covering comprises a capsule having an inner cavity filled with said radiopaque material.

6. The lead as described in claim 2, wherein said covering envelops said fixation element.

7. The lead as described in claim 1, wherein said covering comprises mannitol.

8. The lead as described in claim 1, wherein said fixation element comprises tines and said covering holds said tines in a folded position until it dissolves.

9. The lead as described in claim 1, wherein said fixation element is constrained in position by said covering and is free to move after said covering dissolves.

10. A method of implanting a pacing lead in the heart of a patient, said lead having a fixation element at about its distal end and a covering over at least a portion of said fixation element to facilitate insertion of said lead transvenously, said covering being soluble in body fluids and having dissolving characteristics so that it dissolves only after being in said body fluids for at least a predetermined time, said covering being characterized by a containing radiopaque material within at least a portion thereof to render such portion x-ray visible until it dissolves,

said method comprising inserting said lead and positioning its distal end proximate to the heart wall of the patient,

x-ray monitoring said distal end and determining when said covering has dissolved, and

fixing said fixation element to the inside of the patient'"'"'s heart directly upon determining that said covering has dissolved.

11. The method as described in claim 10, wherein said fixation element is a helix, and said fixing step comprises screwing said helix into said patient'"'"'s heart tissue.

12. An implantable lead having a distal end and an electrode near said distal end, a proximal end, a flexible length between said distal and proximal ends, and a conductor connecting said proximal end and said electrode, said lead having a fixation element at about said distal end for effecting fixation to body tissue at a selected location in a patient, and a covering over at least a portion of said fixation element to facilitate insertion of said lead to a point where said fixation element is proximate to said location, said covering having an inner cavity filled with a radiopaque material to provide an x-ray visible target until said covering dissolves, whereby it can be determined when said covering has dissolved by monitoring said lead distal end with x-ray equipment.