Abstract: Radiofrequency medical devices for ohmic heating of tissue of a patient include a temperature sensor carried by and in thermally conductive relationship with a thermally conductive electrode. The sensor is connected for feedback to a control circuit that modulates RF power applied to the electrode according to the signal received from the temperature sensor. The control circuit and RF power supply alternate between two operating modes. In the first mode the RF power supply applies RF power to the electrode. In the second mode the control circuit senses a signal from the temperature sensor in the absence of RF signal. The control circuit compares the signal from the temperature sensor to a set value and modulates the RF power applied to the electrode in accordance with the set value.

Abstract: Device and method for heating tissue, the device having a catheter shaft for insertion into a patient's body, a chamber formed by a collapsible balloon mounted on the catheter shaft and filled with an electrically conductive fluid, two or more electrical contacts enclosed within the chamber, a power supply for applying an electrical potential to the contacts, and a two or more conductors for connecting each of the contacts to the power supply. The fluid is heated on the basis of I.sup.2 R losses by a radio frequency electric current flowing between the electrodes, and the fluid in turn heats the surrounding tissue by heat transfer through the wall of the chamber. According to the method, the apparatus is inserted into the patient's body, the chamber is filled with an electrically conductive fluid, and an electrical potential is applied to the contacts. The apparatus functions as a temperature source.