Background: Environmental factors have been implicated as major causesof sleep disruption in patients in critical care units, including coronary care units (CCU). We hypothesizedthat myocardial infarction may disturb sleep architecture regardless of the surrounding environmentalfactors. Material/Methods: Twenty consecutive patients with a first-ever acute myocardial infarction(AMI) who were not on sedation or ionotropes underwent a full polysomnography (PSG) in our sleep disorderscenter, away from the CCU environment, within three days of AMI, with a follow-up PSG performed six monthslater. During patient stay in the CCU, each resided in a single room in which normal light-dark exposurewas maintained. Results: The 20 patients with AMI consisted of 18 males and 2 females, of a mean +/-SEage of 51.1+/-1.7 years. Compared with the follow-up PSG, the initial PSG revealed significant increasesin arousal index, spontaneous arousal index, wake time, and REM latency and significant reductions insleep efficiency and REM sleep. Conclusions: Patients with AMI have altered sleep architecture, despitecontrolling for common sleep-disrupting environmental factors. Future research should explore other possibleetiologies of sleep disruption in patients with AMI, including the underlying infarction itself and itsassociated physiological and inflammatory changes.

Keywords: Coronary Care Units, Myocardial Infarction - physiopathology, Polysomnography, Sleep - physiology, Sleep Arousal Disorders - etiology, Sleep Disorders - physiopathology, Sleep, REM