[Chronobiology of acute pulmonary edema in an emergency service]

Some diseases like acute myocardial infarction, sudden death and stroke have been reported to disclose daily, weekly or annual incidence fluctuations. We analyzed the rhythm of pulmonary edema occurrence. We considered 105 consecutive subjects (mean age 73.7 +/- 9.7 years) who came to an Emergency Department because of acute pulmonary edema during a solar year. Chronobiologic analysis was performed using Halberg single cosinor test. Pulmonary edema incidence was higher during the night with an acrophase at 2:14 a.m. (p < 0.001). No significant weekly or circannual rhythms were detected. We discuss the possible relations with diminished heart output, increase in sympathetic tone or partial baroceptor desensitization, occurring at night.