Patent ID: 8041410

Claim:
A method comprising: switching operation of an implantable medical device from a first mode for processing electrical signals to a second mode for processing electrical signals in response to detecting a magnetic field of a magnetic resonance imaging (MRI) device; sensing electrical signals received through at least one lead while operating in the second mode; sensing incidences of gradient magnetic fields with a sensor while operating in the second mode; extrapolating a series of cardiac events based on a history of cardiac event timing; comparing a timing of the electrical signals received through the at least one lead with the sensed incidences of gradient magnetic fields while operating in the second mode; comparing the timing of the electrical signals received through the at least one lead with the extrapolated series of cardiac events; processing electrical signals that coincide with the sensed incidences of gradient magnetic field detection as if the signals were actual cardiac events for purposes of controlling therapy delivery when the electrical signals coincide with one of the cardiac events of the extrapolated series of cardiac events.