Positive fixation cardiac electrode with drug elution capabilities

• US 4,819,661 A
• Filed: 10/26/1987
• Issued: 04/11/1989
• Est. Priority Date: 10/26/1987
• Status: Expired due to Term

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Heil, Ronald W. Jr., Owens, Robert C.
• Primary Examiner(s): Jaworski, Francis
• Assistant Examiner(s): MANUEL, GEORGE C
• Application Number:
  US07/112,519
• Time in Patent Office: 533 Days
• Field of Search: 128/639, 128/642, 128/783, 128/784, 128/785, 128/786
• US Class Current: 607/127
• CPC Class Codes: A61N 1/0565 Electrode heads
• CPC Class Codes: A61N 1/0568 with drug delivery
• CPC Class Codes: A61N 1/0575 with drug delivery

Abstract

A positive fixation cardiac lead includes an electrode sleeve/crimp tube assembly in which a recess is formed for retaining a drug impregnated matrix. The electrode sleeve and crimp tube threadedly engage, to permit insertion of the matrix prior to their assembly. The distal end section of the crimp tube can be provided with a helical groove corresponding to the shape of a fixation helix, with the sleeve and distal section spaced from one another to permit insertion of an annular drug matrix. The distal portion of the electrode sleeve can have an annular groove formed to receive a length of platinum wire, for increased electrode sensitivity.

Claims

1. An intravascular lead implantable inside a patient, including:

an elongate and flexible electrical conductor;

a lead distal end assembly including an electrode, a fixation element fixed with respect to said electrode for effecting penetration into endocardial tissue at a selected location to secure said electrode at said selected location, and a coupling means for electrically and mechanically joining said electrode and a distal end section of said conductor, wherein said electrode includes an elongate annular sleeve and a porous electrode tip at a distal end of the sleeve, said porous electrode tip comprising an electrically conductive fine wire crimped and packed adjacent said distal end of the sleeve, and a screen overlying said wire and fastened to the sleeve to secure said wire relative to the sleeve;

a flexible, biocompatible and dielectric sheath surrounding said conductor along substantially the entire length thereof, and surrounding said assembly along at least a proximal end region thereof;

means forming a chamber in said assembly and open to a distal end thereof; and

a matrix impregnated with a therapeutic drug and retained in said chamber.

2. The intravascular catheter of claim 1 wherein:

said chamber is cylindrical, and is formed in said coupling means and open to a distal end thereof.

3. The intravascular catheter of claim 1 wherein:

said electrode includes an elongate sleeve mounted in spaced apart, surrounding relation to a distal end section of said coupling means, thereby to locate said chamber between said elongate sleeve and said distal end section of the coupling means, and wherein the shape of said matrix corresponds to the shape of said chamber.

4. The intravascular catheter of claim 3 wherein:

said distal end section of the coupling means is cylindrical, and said elongate sleeve is radially spaced apart from said distal end section, thereby to define said chamber as annular.

5. The intravascular lead of claim 4 wherein:

said fixation element comprises a helical coil, and wherein means form a helical groove along said distal end section of said coupling means corresponding to said helical coil, for securing a portion of said helical coil within said groove and threadedly to said coupling means.

6. The intravascular catheter of claim 1 wherein:

said electrode includes an elongate sleeve surrounding a distal end section of said coupling means, and a distal end portion of the sleeve extends beyond the distal end section of the coupling means to define said chamber adjacent said distal end section.

7. The intravascular catheter of claim 6 wherein:

said distal end section of the coupling means is generally cylindrical, and said elongate sleeve is annular, thereby to define said chamber as generally cylindrical.

8. The intravascular lead of claim 6 further including:

means forming a plurality of apertures in a distal end portion of the sleeve open to said chamber and to the exterior of said sleeve at locations distal with respect to said sheath.

9. The intravascular lead of claim 1 wherein:

said electrode includes an elongate, annular sleeve, means defining an annular recess in a distal end of said sleeve, and an electrically conductive fine wire embedded in said recess.

10. The intravascular lead of claim 1 wherein:

said fixation element comprises a helical coil, and wherein means form a helical groove along a distal end section of the coupling means corresponding to said helical coil, for securing a portion of said helical coil within said groove and threadedly to said coupling means.

11. The intravascular, implantable lead comprising:

an elongate and flexible electrical conductor;

a lead distal end assembly including an electrode sleeve, a fixation element fixed with respect to the electrode sleeve for effecting penetration into endocardial tissue at a selected location to secure said electrode sleeve at said selected location, and a coupling means for electrically and mechanically joining said electrode sleeve and a distal end of said conductor;

a flexible, biocompatible and dielectric sheath surrounding said conductor along substantially the entire length thereof, and surrounding said assembly along at least a proximal end region thereof;

means forming a chamber in said electrode sleeve, and a matrix impregnated with a therapeutic drug, said chamber being open to a proximal end of said electrode sleeve to permit proximal insertion of said matrix into said chamber;

wherein a distal end section of said coupling means is adapted to engage the proximal end of said electrode sleeve, following said proximal insertion of said matrix, to retain said matrix in said chamber and to form a substantially fluid tight seal between said matrix and said conductor; and

means forming a fluid passageway for movement of body fluid into and out of said chamber distally with respect to said coupling means.

12. The intravascular, implantable lead of claim 11 wherein:

said electrode sleeve and said distal end section threadedly engage.

13. The intravascular, implantable lead of claim 11 further including:

a porous electrode tip at a distal end of said electrode sleeve, said tip comprising an electrically conductive fine wire crimped and packed adjacent said distal end, and a screen overlying said wire and fastened to the sleeve to secure said wire relative to the sleeve.

14. An intravascular lead implantable inside a patient, including:

an elongate and flexible electrical conductor;

a lead distal end assembly including an electrode, a helical coil for effecting penetration into endocardial tissue at a selected location to secure said electrode at said selected location, and a coupling means for electrically and mechanically joining said electrode and a distal end section of said conductor; and

means forming a helical groove along a distal end section of said coupling means and corresponding to said helical coil, said helical coil including a proximal portion surrounding said distal end section of said coupling means and lying within said groove, whereby said proximal portion of said helical coil is within said groove and thereby threadedly secured to said coupling means.

15. An intravascular lead implantable inside a patient, including:

an elongate and flexible electrical conductor;

a lead distal end assembly including an electrode, a helical coil for effecting penetration into endocardial tissue at a selected location to positively secure said electrode at said selected location, and a coupling means for electrically and mechanically joining said electrode and a distal end section of said conductor, said electrode including an elongate annular sleeve and an electrode tip at a distal end of said sleeve, said electrode tip having a porosity of at least 75%;

a flexible, biocompatible and dielectric sheath surrounding said conductor along substantially the entire length thereof, and surrounding said assembly along at least a proximal end region thereof;

means forming a chamber in said assembly and open to a distal end thereof; and

a solid matrix impregnated with a therapeutic drug and retained in said chamber.