Implantable electrode with active fixation means

Claim 2

A lead assembly for implantation in a patient, said assembly comprising an electrode head adapted for insertion into a chamber of the patient's heart and having a recess along a portion of said head, a lead connected to said electrode head for coupling said head to a source of electrical energy for delivery of electrical stimulation via said electrode head to cardiac tissue within said chamber, and a substantially rigid fixing hook coupled in substantially stationary relationship to said electrode head for rotation with said head about the axis of said lead and arranged relative to said recess for engaging tissue upon rotation of the head in the general direction in which the tip of said hook projects, to affix said head in stimulating relationship with cardiac tissue within said chamber.

Claim 3

The lead assembly of Claim 1, in which the tip of said fixing hook is in the region of said recess.

Claim 4

The lead assembly of Claim 2, in which said fixing hook lies substantially entirely within the contour of said electrode head viewed in the axial direction of said lead.

Claim 5

The lead assembly of Claim 2, in which at least the tip of said fixing hook lies outside the contour of said electrode head viewed in the axial direction of said lead.

Claim 6

The lead assembly of Claim 2, in which said fixing hook is a rigid wire bent to a curvature closely conforming to the contour of said electrode head viewed in the axial direction of said lead.

Claim 7

The lead assembly of Claim 5, in which said contour of said electrode head is substantially circular.

Claim 8

The lead assembly of Claim 6, in which the distance between the tip of said fixing hook and the surface of said electrode head forming said recess and confronting said tip in the direction normal to the axis of said lead is greater than or equal to the difference between the radius of said head and the diameter of said wire.

Claim 9

The lead assembly of Claim 7, in which said recess has an axial length greater than or equal to 65% of the diameter of said electrode head.

Claim 10

The lead assembly of Claim 8, in which the axial length of said recess is 80% of the diameter of said electrode head.

Claim 11

The lead assembly of Claim 8, in which the tip of said fixing hook lies opposite the deepest portion of said recess.

Claim 12

The lead assembly of Claim 10, in which the axial distance between the tip of said electrode head and the tip of said fixing hook is greater than or equal to the diameter of said electrode head.

Claim 13

The lead assembly of Claim 11, in which said recess extends through an angle of approximately 270 degrees about the axis of said electrode head.

Claim 14

The lead assembly of Claim 11, in which the opening between the tip of said fixing hook and the beginning of said recess is bounded by an angle less than or equal to 130 degrees about the axis of said electrode head.

Claim 15

The lead assembly of Claim 11, in which said recess extends completely about the axis of said electrode head in an axial band.

Claim 16

The lead assembly of Claim 14, in which said recess is of unequal depth along radii lying in a plane normal to the axis of said electrode head.

Claim 17

The lead assembly of Claim 6, in which said fixing hook wire is fastened to said electrode head at a point within said recess, and said fixing hook lies substantially entirely in a plane normal to the axis of said electrode head.

Claim 18

The lead assembly of Claim 6, in which said fixing hook wire is fastened to said electrode head at a point adjacent the side of said recess opposite the side at which the tip of said electrode head is located, and said fixing hook has the shape of a spiral coaxial with said head.

Claim 19

The lead assembly of Claim 6, further including at least one additional fixing hook of substantially the same character as the first-named fixing hook, the tips of said fixing hooks being displaced axially along said electrode head.

Claim 20

The lead assembly of Claim 6, in which said recess is defined by a continuous smooth surface without sharp edges and corners.

Claim 21

The lead assembly of Claim 6, in which at least the tip of said electrode head is provided with a surface conducive to electrical stimulation.

Claim 22

An implantable electrode assembly for cardiac stimulation, comprising an electrode having a tip configured for delivering electrical stimulation to cardiac tissue, a lead connected to said electrode for coupling said electrode tip to a source of electrical stimulation, and a rigid fixing hook fastened to one of said electrode and said lead at a point remote from said electrode tip and lying at least partly within a recess in said one of said electrode and said lead, said fixing hook having a curvature closely conforming to the contour of said electrode head and having a hook tip lying at least slightly outside said contour and cooperating with said recess to engage cardiac tissue therebetween when said electrode is positioned in a chamber of the heart and rotated about the axis of said lead in the general direction in which said hook tip is pointed.

Claim 23

An implantable electrode assembly for cardiac stimulation, comprising an electrode having a tip configured for delivering electrical stimulation to cardiac tissue, a lead connected to said electrode for coupling said electrode tip to a source of electrical stimulation, and a rigid fixing hook fastened to one of said electrode and said lead at a point remote from said electrode tip and lying at least partly within a recess in said one of said electrode and said lead, said fixing hook having a curvature closely conforming to the contour of said electrode head and having a hook tip lying at least slightly outside said contour and cooperating with said recess to engage cardiac tissue therebetween when said electrode is positioned in a chamber of the heart and rotated about the axis of said lead in the general direction in which said hook tip is pointed.