Epicardial lead having low threshold, low polarization myocardial electrode

Abstract

An epicardial pacing lead for the delivery of stimulation energy to and the sensing of electrical signals from the myocardium of a human heart. The lead includes an electrode which penetrates the myocardium and serves to anchor the lead to the heart. The lead contains a drug for delivery through the electrode, to the myocardium. The electrode is provided with a bore for passage of the drug to the stimulation and fixation site.

We claim: 
     
       1. In a cardiac pacing lead of the type including an elongated conductor having a proximal end and a distal end, a connector electrically coupled to the proximal end of said conductor, an electrode including fixation means for penetrating the heart tissue, coupled to the distal end of said conductor, and an elongated insulative sheath covering said conductor extending from said electrical connector to said electrode, the improvement wherein: said electrode includes means for dispensing an anti-inflammatory drug comprising drug storage means for retaining said anti-inflammatory drug and a passageway through which said drug may travel, open to the exterior of said electrode at said fixation means.   
     
     
       2. A pacing lead according to claim 1 wherein the passageway of said dispensing means is provided with porous means for metering the flow of said drug. 
     
     
       3. An electrode according to claim 2 wherein said porous means is fabricated of sintered metal particles. 
     
     
       4. An electrode according to claim 1 wherein said drug storage means comprises porous, absorptive means located within said passage way. 
     
     
       5. A lead according to claim 4 wherein said porous means is fabricated of sintered metal particles. 
     
     
       6. A lead according to claim 1 wherein said drug storage means comprises a drug storage chamber, pierceable by means of a hypodermic syringe whereby said drug storage chamber may be loaded with said drug. 
     
     
       7. A lead according to claim 1 wherein said drug storage means comprises a drug storage chamber, containing said drug compounded in the form of a controlled release means for gradually releasing said drug. 
     
     
       8. In a cardiac pacing lead of the type comprising an elongated conductor having a proximal end and a distal end, a connector electrically coupled to the proximal end of said conductor, an electrode including fixation means for penetrating the heart tissue coupled to the distal end of said conductor, and an elongated insulative sheath covering said conductor, extending from said electrical connector to said electrode, the improvement comprising: means for dispensing an anti-inflammatory drug at said fixation means comprising a drug storage chamber for retaining said anti-inflammatory drug, and wherein said electrode has a proximal end, located within said drug storage chamber and a distal end bearing said fixation means for penetrating heart tissue, said dispensing means including a passageway through said electrode through which said drug may travel, the passageway of said electrode open to said storage chamber at the proximal end of said electrode and open to the exterior of said electrode at said fixation means at the distal end of said electrode.   
     
     
       9. A pacing lead according to claim 8 wherein said passageway of said electrode is provided with porous means for metering the flow of said drug. 
     
     
       10. An electrode according to claim 9 wherein said porous means is fabricated of sintered metal particles. 
     
     
       11. In a cardiac pacing lead of the type comprising an elongated conductor having a proximal end and a distal end, a connector electrically coupled to the proximal end of said conductor, an electrode including fixation means for penetrating the heart tissue coupled to the distal end of said conductor, and an elongated insulative sheath covering said conductor, extending from said electrical connector to said electrode, the improvement comprising: means for dispensing an anti-inflammatory drug adjacent said fixation means, comprising a passageway within said electrode, through which said drug may travel, open to the exterior of said electrode at said fixation means, the passageway of said electrode including means for storing said anti-inflammatory drug.   
     
     
       12. A pacing lead according to claim 11 wherein said storage means comprises means for absorbing said drug through said passageway. 
     
     
       13. A lead according to claim 12 wherein said storage means comprises a porous structure fabricated of sintered metal particles. 
     
     
       14. A method of fabricating a cardiac pacing lead of the type including an electrode having a proximal end coupled to an elongated conductor and a distal end including fixation means for penetrating the heart tissue, comprising the steps of: filling a cardiac electrode of the type including a fixation means and a lumen open to said fixation means with an absorptive material;   coupling said electrode to an electrical conductor; and   placing said fixation means of said electrode in a solution of a desired drug, allowing said absorptive substance within said lumen of said electrode to absorb said drug.