SYSTEM AND METHOD FOR PROTECTING AGAINST MAGNETIC FIELDS PRODUCED BY MRI

An implantable cardiac device that detects and protects against strong magnetic fields produced by MRI equipment is disclosed. The device has a magnetic field sensor for detecting the presence of a relatively weak static magnetic field (102, 110, 118, 122) of a level equivalent to that of a permanent magnet in the vicinity of the device. The device is switched from a standard operating mode (100) where the nominal functions of the device are active, to a specific protected MRI mode (114, 116) in the presence of a magnetic static field of a level corresponding to that emitted by MRI equipment. The device further temporarily switches the device from the standard operating mode (100) to an MRI stand-by state (108) when a magnetic field is detected by the magnetic field sensor such that a subsequent detection of a magnetic field switches the device from an MRI stand-by state to the specific protected MRI mode.