Final answer:
Pacemaker settings DDD, DOO, etc. represent the rhythm mode of the pacemaker, determining how the pacemaker senses and delivers pacing pulses.
Step-by-step explanation:
In pacemaker settings, DDD, DOO, etc. represent the rhythm mode of the pacemaker.
Rhythm mode refers to how the pacemaker senses the heart's electrical signals and delivers pacing pulses. In the DDD mode, the pacemaker senses the heart's electrical activity in both the atria and the ventricles, and it can pace both chambers. In the DOO mode, the pacemaker paces the ventricles at a fixed rate without sensing the heart's electrical activity.