Patent ID: 7879029

Claim:
A system for selectively energizing electrodes on an ablation catheter, comprising: a catheter having a catheter body, and a tip section carrying a tip electrode and a plurality of radial electrodes proximal the tip electrode; a signal generator to provide impedance test signals; a multiplexer comprising at least two channels, each channel being in communication with a radial electrode, wherein the multiplexer is adapted to operate in a first mode wherein the multiplexer continuously switches between the channels to change electrical connection of the signal generator to a specific radial electrode, and a second mode wherein the multiplexer connects the signal generator to a single selected radial electrode; an impedance measurement circuitry adapted to provide impedance measurements of each radial electrode as an indication of tissue contact when said multiplexer is operating in said first mode; a microcontroller adapted to command the multiplexer to operate in said first mode or said second mode; a memory adapted to store the impedance measurements; an ablation energy source adapted to energize the tip electrode and the single selected radial electrode, wherein the ablation energy source is separate from the signal generator; and a switch responsive to the microcontroller to connect the ablation energy source to the single selected radial electrode via the multiplexer operating in the second mode.