ICDs are completely compatible with catching some Zs. Right away, it might be uncomfortable to sleep on your implant side, but over time it becomes a breeze. If your device is pacing you, that also may take some getting used to. If, after some time, the lack of sleep has you off your rocker you should really ask your doctor. If you find yourself in the terrifying reality of speaking exclusively in rhyme, seek immediate attention from an English teacher.