Patent ID: 8165693

Claim:
An implantable medical device (IMD) for operating in a modified impedance mode, comprising: a stimulation unit to provide an electrical stimulation signal through a lead operatively coupled to said IMD; and a controller comprising a signal detection unit to receive an indication selected from the group consisting of an indication of the presence of a radio frequency (RF) coupled energy on said lead and an indication of the future presence of said RF coupled energy on said lead, and an impedance unit to modify an impedance of said lead based upon said indication received by said signal detection unit, wherein said impedance unit comprises: at least one of a capacitive impedance, an inductive impedance, a resistive impedance, a short-circuit, and an open circuit; a switching network capable of switching at least one of said capacitive impedance, inductive impedance, resistive impedance, said open circuit, and said short circuit to modify said impedance of said lead; and an active cancellation unit, configured to provide upon the lead a controlled current signal for actively reducing said coupled energy.