Patent ID: 7419486

Claim:
A method of treating cardiac tissue, the method comprising the steps of filling at least a distal portion of a catheter lumen of a catheter with conductive hydrogel, said catheter lumen extending adjacent to a catheter active region on a catheter outer surface; guiding said catheter active region into contact with the cardiac tissue to be treated; activating a hydrogel displacement device to advance said conductive hydrogel toward said active region until said conductive hydrogel broaches said catheter outer surface to thereby introduce at least one conductive hydrogel virtual electrode against the cardiac tissue; directing ablative energy through said at least one conductive hydrogel virtual electrode and into the cardiac tissue; and activating said hydrogel displacement device to retract said conductive hydrogel and thus said at least one conductive hydrogel virtual electrode from contact with the cardiac tissue and back into said catheter lumen.