Circadian variation in the frequency of myocardial infarction and death associated with acute pulmonary edema.

The records of 103 patients hospitalized for acute pulmonary edema were reviewed to determine the relationship between short-term outcome and time of presentation to the emergency department. Although only 17% of the patients arrived in the emergency department during the early afternoon hours, half of the deaths in the study occurred in this group. Patients presenting between noon and four PM had a significantly higher incidence of acute myocardial infarction (76% v. 28%, p = 0.03) and death (47% v. 9% p = 0.03) compared with patients presenting at other times. Differences in the pathophysiology of daytime versus nocturnal acute pulmonary edema may account for some of the variation in outcome.