Kuniyoshi S et al. - The diurnal variation in the onset of Myocardial Infarction (MI) in Obstructive Sleep Apnea (OSA) patients is strikingly different from the diurnal variation in non-OSA patients. Patients with nocturnal onset of MI have a high likelihood of having OSA. These findings suggest that OSA may be a trigger for MI. Patients having nocturnal onset of MI should be evaluated for OSA, and future research should address the effects of OSA therapy for prevention of nocturnal cardiac events.