Importance

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Abstract

An implantable cardiac stimulation lead comprises an elongated electrical conductor with an electrode configured to deliver a tiered level of drug therapy to a patient. An insulative electrical sheath covers the electrical conductor and an electrical connector is coupled to the proximal end of the electrical conductor, adapted for connection with the pulse generator. An electrically conductive electrode is located at a distal end of the electrical conductor whose proximal end is adapted for connection to an implantable stimulation device, the electrode having an interior cavity and an axial bore extending between an exterior surface and the interior cavity. A matrix member, preferably composed of silicon rubber, is received within the interior cavity and contains a therapeutic drug. The exterior surface is coated and the bore is filled with a therapeutic drug-hydrophilic wetting agent compound and the bore is filled with a wetting agent compounded with the therapeutic drug such that tiered delivery to a recipient of the therapeutic drug is achieved first from the exterior electrode surface, then from the bore, and finally from the matrix member. The opening of the bore at the exterior surface of the electrode is between about 0.1% and 50% of the entire surface area of the electrode and is insufficient to allow the intrusion of body fluid from the recipient into the cavity in the absence of a wetting agent, a hydrophilic, water soluble, biocompatible polymer. The diameter of the bore is between about 0.001 inches and 0.035 inches.

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First Claim