Patent ID: 7131445

Claim:
A method of forming a lesion in body tissue comprising the steps of providing a probe capable of contacting body tissue to be treated, delivering electromagnetic energy to the probe such as to raise the temperature of the tissue in contact with the probe, measuring the temperature of the probe, and controlling the delivery of the electromagnetic energy such that: a) in an initial ramp-up phase, the temperature of the probe is raised rapidly to a first threshold temperature of between 90° and 105° C., b) in a second equilibrating phase, the temperature of the probe is held substantially constant for a period of time to allow the temperature of different parts of the probe to equilibrate, and c) in a subsequent treatment phase, the temperature of the probe is raised to a second, higher threshold temperature of between 100° C. and 115° C. such that a lesion is formed in the tissue adjacent the probe without the complete removal of electrolytes in the tissue adjacent to the probe through vaporisation.