Tissue ablation catheter with an insulator between inner and outer electrodes

A tissue ablation catheter with an insulator between inner electrodes and outer electrodes, comprising:

• a tubular element comprising
• a distal end;
• a proximal end opposite said distal end;
• a longitudinal axis;
• an inner surface surrounding a lumen;
• an outer surface;
• and,
• an electrical insulator between said inner surface and said outer surface;
• one or more inner electrodes coupled to said inner surface, each offset away from said distal end in a proximal direction towards said proximal end;
• one or more outer electrodes coupled to said outer surface, each offset from said distal end in said proximal direction towards said proximal end, wherein said one or more outer electrodes are separated from said one or more inner electrodes by said electrical insulator;
• a controller coupled to said one or more inner electrodes and to said one or more outer electrodes;
• wherein
• said distal end is configured to be placed proximal to a tissue to be ablated;
• and,
• said controller is configured to set voltages of said one or more inner electrodes and voltages of said one or more outer electrodes to generate an electric field outside said tubular element that induces ablation of said tissue to be ablated by electroporation.