Cardiac lead having multiple ring electrodes

Claim 1

An endocardial lead comprising: an elongated, flexible electrically insulative tubing having proximal and distal ends and an outer surface, said insulative tubing having at least one pair of closely spaced apertures extending through the wall of the tubing at predetermined positions intermediate said proximal and distal ends; at least one elongated, flexible, electrical conductor positioned within the insulative tubing and extending for substantially the entire length of the insulative tubing, said electrical conductor having an insulative coating surrounding the electrical conductor over substantially the entire length thereof except for proximal and distal terminal portions; the proximal terminal portion of said electrical conductor being connected to an electrical connector adapted for connection to a tissue stimulating or monitoring device; the distal terminal portion of said electrical conductor extending out of one aperture of said pair of apertures in said insulative tubing, first axially forwardly, second around the circumference of the tubing defining a loop, third under or over the axially forwardly extending portion of said conductor and fourth axially forwardly over or under the loop to and into the other aperture, whereby said electrical conductor is fixed in a knot formation at the distal end thereof in such a manner as to prevent the pulling out of said conductor from said tubing; and, at least one metal sleeve defining a ring electrode on the outer surface of said insulative tubing, said metal sleeve having an inner surface and being frictionally received over said insulative tubing and positioned over said at least one pair of apertures having an electrical contact surface on the inner surface of the at least one metal sleeve in contact with said distal terminal portion of said conductor whereby, when said metal sleeve is frictionally received over said insulative tubing and positioned over said at least one pair of apertures, said contact surface presses against and makes electrical contact with said distal terminal portion of said conductor between said pair of apertures.