Dying in the dark: sunshine, gender and outcomes in myocardial infarction.

We report a natural experiment that took place in a cardiac intensive care unit (CICU). We had been alerted to the possibility that sunny rooms would be conducive to better outcomes by our findings in the psychiatric unit, and by reports that depressed cardiac patients did less well than those in normal mood. The 628 subjects were patients admitted directly to the CICU with a first attack of myocardial infarction (MI). Outcomes of those treated in sunny rooms and those treated in dull rooms were retrospectively compared for fatal outcomes and for length of stay in the CICU. Patients stayed a shorter time in the sunny rooms, but the significant difference was confined to women (2.3 days in sunny rooms, 3.3 days in dull rooms). Mortality in both sexes was consistently higher in dull rooms (39/335 dull, 21/293 sunny). We conclude that illumination may be relevant to outcome in MI, and that this natural experiment merits replication.