Catheter with an irrigated composite tip electrode

Abstract

Various catheter designs with irrigated tip electrodes are provided for reducing the heating of the tip resulting from RF biasing. The electrode tip of the catheter may be comprised of a highly thermal conductivity layer covered by a biologically compatible material and having irrigation or irrigation channels for removing excess thermal energy from the catheter tip and the surrounding area of the catheter tip. The catheter tip may be designed with multiple irrigation channels, multiple channel pathways, and/or exterior shapes to improve the cooling of the tip. These approaches may be used individually or in combination to produce a catheter tip with improved heat dissipation characteristics.

What is claimed is:  
     
         1 . A medical ablation electrode, comprising: 
 a biologically compatible outer layer;    a thermally conductive inner layer; and    an irrigation channel in contact with said inner layer for channeling cooling fluid.    
     
     
         2 . The electrode of  claim 1 , wherein said outer layer is platinum iridium alloy.  
     
     
         3 . The electrode of  claim 2 , wherein said platinum iridium alloy is composed of approximately 90 percent platinum and 10 percent iridium.  
     
     
         4 . The electrode of  claim 3 , wherein said inner layer is copper.  
     
     
         5 . The electrode of  claim 1 , wherein said outer layer is plated onto said inner layer.  
     
     
         6 . The electrode of  claim 1 , wherein said inner layer is in contact with said outer layer, whereby said inner layer dissipates heat from said outer layer to fluid flowing through said irrigation channel.  
     
     
         7 . The electrode of  claim 1 , wherein said irrigation channel is formed through said inner layer.  
     
     
         8 . The electrode of  claim 1 , wherein an inner surface of said inner layer forms said irrigation channel.  
     
     
         9 . The electrode of  claim 1 , further comprising an irrigation exit port extending laterally through said inner and outer layers, said exit port being in fluid communication with said irrigation channel.  
     
     
         10 . The electrode of  claim 9 , wherein said irrigation channel comprises a wall that is covered by a layer of a biologically compatible material.  
     
     
         11 . The electrode of  claim 1 , further comprising a RF ablation wire electrically coupled to said inner layer.  
     
     
         12 . A medical ablation electrode, comprising: 
 a thermally conductive proximal section having a substantially distally facing wall;    an irrigation channel formed within said proximal section for channeling cooling fluid;    a thermally conductive distal section having an exterior surface; and    one or more irrigation exit ports extending through said distally facing wall proximal to said distal section, whereby said cooling fluid is flowed over said exterior surface of said distal section when said cooling fluid is conveyed through said irrigation channel.    
     
     
         13 . The electrode of  claim 12 , wherein said distal section comprises a neck and a head, said neck being mounted to said distally facing wall.  
     
     
         14 . The electrode of  claim 12 , wherein said distal section has a substantially uniform diameter.  
     
     
         15 . The electrode of  claim 12 , wherein said proximal and distal sections form a single unibody structure.  
     
     
         16 . The electrode of  claim 12 , wherein said proximal and distal sections consist essentially of a biologically compatible material.  
     
     
         17 . The electrode of  claim 12 , further comprising a RF wire electrically coupled to said proximal section.  
     
     
         18 . A medical ablation electrode, comprising: 
 a thermally conductive housing having one or more concave sections and one or more convex sections;    an irrigation channel formed within said housing for channeling cooling fluid;    one or more irrigation exit ports adjacent said one or more concave sections of said housing, said one or more exit ports being in fluid communication with said irrigation channel.    
     
     
         19 . The electrode of  claim 18 , wherein said one or more concave sections comprises a plurality of concave sections, and said one or more irrigation exit ports comprises a plurality of irrigation exit ports.  
     
     
         20 . The electrode of  claim 18 , wherein said housing forms a unibody structure.  
     
     
         21 . The electrode of  claim 18 , wherein said housing consists essentially of a biologically compatible material.  
     
     
         22 . The electrode of  claim 18 , further comprising a RF wire electrically coupled to said housing.  
     
     
         23 . A medical ablation electrode, comprising: 
 a thermally conductive irrigation tube having an irrigation channel for channeling cooling fluid, said irrigation tube having a spiral shape.    
     
     
         24 . The electrode of  claim 23 , wherein said irrigation tube comprises an exit port.  
     
     
         25 . The electrode of  claim 23 , wherein said irrigation tube consists essentially of a biologically compatible material.  
     
     
         26 . The electrode of  claim 23 , further comprising a RF wire electrically coupled to said irrigation tube.  
     
     
         27 . A medical ablation electrode, comprising: 
 a thermally conductive rigid housing; and    one or more flow-through channels formed by an external surface of said rigid housing for channeling biological fluids over said external surface adjacent said flow-through channels.    
     
     
         28 . The electrode of  claim 27 , wherein said one or more flow-through channels extend laterally through said rigid housing.  
     
     
         29 . The electrode of  claim 27 , wherein said rigid housing consists essentially of a biologically compatible material.  
     
     
         30 . The electrode of  claim 27 , further comprising a RF wire electrically coupled to said rigid housing.  
     
     
         31 . A medical ablation electrode, comprising: 
 an inner cylinder;    an inner irrigation channel extending through said inner cylinder for channeling cooling fluid;    an outer cap mounted in a concentrically overlapping arrangement with said inner cylinder, and    an annular irrigation channel formed between an inner surface of said outer cap and an outer surface of said inner cylinder for channeling said cooling fluid, wherein said annular irrigation channel is in fluid communication with said inner irrigation channel.    
     
     
         32 . The electrode of  claim 31 , further comprising one or more irrigation exit ports in fluid communication with said annular irrigation channel.  
     
     
         33 . The electrode of  claim 31 , further comprising a pin that extends through said inner cylinder and said outer cap for mounting said outer cap to said inner cylinder.  
     
     
         34 . The electrode of  claim 31 , further comprising an annular entry port formed between a distal end of said outer cap and a distal end of said inner cylinder, wherein said entry port is in fluid communication with said inner irrigation channel.  
     
     
         35 . The electrode of  claim 31 , wherein said inner cylinder and outer cap are composed of a thermally conductive material.  
     
     
         36 . The electrode of  claim 31 , wherein said outer cap consists essentially of a biologically compatible material.  
     
     
         37 . The electrode of  claim 31 , further comprising a RF ablation wire electrically coupled to said inner cylinder.  
     
     
         38 . A medical ablation electrode, comprising: 
 a thermally conductive housing comprising a wall; and    an irrigation channel formed in said housing for channeling cooling fluid;    wherein said housing wall has a thickness that is less than a diameter of said irrigation channel divided by the number 2.    
     
     
         39 . The electrode of  claim 38 , wherein said housing consists essentially of a biologically compatible material.  
     
     
         40 . The electrode of  claim 38 , further comprising a RF ablation wire electrically coupled to said housing.  
     
     
         41 . The electrode of  claim 38 , wherein said housing wall has a thickness that is less than a diameter of said irrigation channel divided by 4.  
     
     
         42 . The electrode of  claim 38 , wherein said housing wall has a thickness that is less than a diameter of said irrigation channel divided by 10.