Implantable Cardiac Prosthesis Generator Having Protection From an MRI Examination

A generator for an active implantable medical device having a lead for one of a cardiac stimulation, a resynchronization and a defibrillation operation, said generator comprising:

• a metal housing having a ground potential;
• an electronic circuit housed in said metal housing having a first generator connection terminal and a second generator connection terminal, wherein the first and second generator connection terminals respectively receive a first and second conducting terminals of a lead;
• a plurality of switches, and
• a switch controller controlling the plurality of switches in a first mode of operation in which at least one of the first and second generator connection terminals is connected to said electronic circuit for sensing cardiac activity and delivering stimulation pulses, and a safekeeping mode of operation in which one of the first and second generator connection terminals is connected to the metal housing ground and the other of the first and second generator connection terminals is connected to the electric circuit for sensing cardiac activity and delivering stimulation pulses.

A method for protection of an active implantable medical device having one of a cardiac stimulation, a resynchronization and a defibrillation prosthesis, the method comprising:

• providing a generator, the generator comprising:
• providing a lead having a distal end, a proximal end, a first electrode disposed at the distal end, a second electrode disposed in a vicinity of the first electrode, a first terminal disposed at the proximal end, a second terminal disposed in a vicinity of the first terminal, a first conductor extending along a length of the lead from the distal end to the proximal end and connecting the first electrode to the first terminal, and a second conductor extending along the length of the lead from the distal end to the proximal end and connecting the second electrode to the second terminal;
• providing an electronic circuit in a metal housing of the generator, the metal housing having a ground potential, the electronic circuit having a generator connection terminal and a plurality of switches, the generator connection terminal being connected to the first terminal and the second terminal of the lead by the plurality of switches;
• controlling the plurality of switches;
• and
• operating the generator in a safekeeping mode of operation by connecting one of said first and second electrodes to said metal housing ground.