An ablation apparatus has an expandable member that is inserted into an organ of a body and ablates all or a selected portion of the inner layer of the organ. Electrolytic solution fills the expandable member, and the expandable member includes a plurality of apertures from which electrolytic solution flows from the expandable member. First and second fluid conduits, which can be first and second conforming members, are in a surrounding relationship to the expandable member. The second conforming member, including a conductive surface, is made of a material that provides substantial conformity between the conductive surface and a shape of the inner layer of the organ. A plurality of electrodes is positioned between the two conforming members. The expandable member serves as an insulator to RF energy. Each electrode includes an insulator formed on a surface of the electrode positioned adjacent to the second conforming member. The combination of sandwiching the electrodes between the two conforming members, and the use of two insulators, one on the electrode and the other on the expandable member, provides selectable ablation of the inner layer of the organ. A feedback device is included and is responsive to a detected characteristic of the inner layer. The feedback device provides a controlled delivery of RF energy to the electrodes.