DETECTION OF STRONG STATIC MAGNETIC FIELDS AND MRI EXAMINATION SAFEKEEPING FOR AN IMPLANTABLE CARDIAC PROSTHESIS

摘要

An implantable medical device detects a strong static magnetic field associated with an MRI imaging instrument and operates in a safekeeping operating mode. The device (10) includes an electronic circuit for the detection/stimulation of a cardiac activity (16), a weak field sensor (22) detecting the presence of a first magnetic field of a permanent magnet being located in proximity to the device, a strong field sensor (20) detecting the presence of a second magnetic field of an MRI imaging instrument during the course of an MRI examination. The electronic circuit is placed in a safekeeping operating mode protected from the magnetic field of an MRI imaging instrument when the weak field sensor detects the first magnetic field and the strong field sensor detects the second magnetic field. The strong field sensor is a sensor that is selectively activated on detection of a magnetic field by the weak field sensor.