The patient is also informed of the risks and benefits of the procedure and a written informed consent must be signed in front of a witness. Mechanism of Radiofrequency Lesioning Frictional heat is generated by molecular movement in a field of alternating electrical current at radiofrequency. An electromagnetic field is created around an active electrode when the frequency is set above 250 kHz. The active electrode is placed at the site for lesioning and an indifferent electrode is placed to minimize passage of current through the myocardium. Heat is generated in the tissues, which conducts to the active electrode.
Heat is generated as current flows through a probe with a built in thermocouple needle.
The heat is not emitted from the probe itself but from the current movement which generates the heat as it passes through the tissues. The lesion is formed once the neural temperature exceeds 45 degrees centigrade. Temperature above ninety degrees centigrade can cause boiling and tissue tearing with electrode removal. Lesion plateaus with time. After sixty seconds at a certain temperature, lesion growth is minimal.