Systems and methods using a porous electrode for ablating and visualizing interior tissue regions

A system for ablating heart tissue comprising

• a catheter tube having a distal end for deployment in a heart chamber,
• a fluid source of a medium containing ions,
• an electrode on the distal end of the catheter tube comprising a wall having a surface capable of contacting tissue and peripherally surrounding an interior area, a lumen to convey a medium containing ions into the interior area, an electrically conductive element in the interior area,
• an electrical path coupling the electrically conductive element to a source of energy to transmit the energy,
• at least a portion of the wall comprising a porous material sized to pass ions contained in the medium, thereby establishing ionic transport of electrical energy from the electrically conductive element through the medium and wall to ablate heart tissue, and
• an imaging element in the interior area coupled to a source of visualizing energy for visualizing tissue, and
• at least a portion of the wall also being generally transparent to the visualizing energy.