Triggers and noise should be available as information in recorded electrograms
in memories of implantable medical devices. Particularly where the recording of
electrogram data is done in the far field, there will be considerable noise and
the interpretation of ECG's reproduced from such recorded data will benefit from
the storing of information regarding contemporaneous noise. By storing contemporaneous
trigger data and noise data directly in the ECG data, recordings of the ECG data
become more useful for physician use when played back through an external display
system with minimal loss of ECG data, since out of range values are employed for
the noise and trigger information and this non-ECG data is limited in size to no
longer than individual point values of the ECG signal.