Background: Environmental factors have been implicated as major causes of sleep disruption in patients in critical care units, including coronary care units (CCU). We hypothesized that myocardial infarction may disturb sleep architecture regardless of the surrounding environmental factors.
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 disorders center, away from the CCU environment, within three days of AMI, with a follow-up PSG performed six months later. During patient stay in the CCU, each resided in a single room in which normal light-dark exposure was maintained.
Results: The 20 patients with AMI consisted of 18 males and 2 females, of a mean +/-SE age of 51.1+/-1.7 years. Compared with the follow-up PSG, the initial PSG revealed significant increases in arousal index, spontaneous arousal index, wake time, and REM latency and significant reductions in sleep efficiency and REM sleep.
Conclusions: Patients with AMI have altered sleep architecture, despite controlling for common sleep-disrupting environmental factors. Future research should explore other possible etiologies of sleep disruption in patients with AMI, including the underlying infarction itself and its associated physiological and inflammatory changes.