lesion line so that the cardioblate pen or other radiofrequency ablation device can be guided along the line that has been established by the delivery of the conductive fluid dyes such as those used for tattoos are believed suitable as are some tissue dyes toluene blue and methylene blue are examples of dyes believed suitable for use in the present invention in yet another aspect the ink or dye can be thermochromic such that it changes color when heated to a temperature which indicates that a lesion has been formed by the application of radiofrequency energy typically temperatures above about 50 to 55 degrees c are required to cause cell death in an ablative lesion made by radiofrequency ablation and the photochromic material would preferably change color in that temperature range in still another aspect the injected fluid can include a viscous enhancing agent or fluid added to reduce or retard fluid diffusion after delivery reducing the diffusion of a cytotoxic and or conductive fluid can reduce the width of the resulting lesion reducing the diffusion of a protective fluid can maintain the protective fluid in a desired position adjacent the cytotoxic and or conductive fluid to serve its protective function viscous fluids such as dextrose or glycerol may be added to increase the viscosity of a delivered fluid the viscous fluids or agents can provide a fluid viscosity of at least about twice that of water it will be appreciated by those skilled in.