Circadian variation in onset of acute cardiogenic pulmonary edema is independent of patients' features and underlying pathophysiological causes

Background The present study aimed to confirm the existence of a circadian pattern in the onset of acute pulmonary edema (APE) and to verify whether s ex, age, preexisting diseases, and clinical causes determining the event ma y influence it. Subjects and Methods. The study considered all consecutive cases of APE observed at the St. Anna General Hospital of Ferrara, Italy, d uring a 7-year period from January 1, 1992, to December 31, 1998. The sampl e population was divided into subgroups by sex, age (<75 and greater than o r equal to 75 years), presence or absence of diabetes and hypertension, cli nical causes determining the event (i.e., acute myocardial infarction (AMI) , pulmonary embolism, arrhythmias). The most important associated or concom itant dis eases were also considered (i.e., coronary heart disease and angi na, previous myocardial infarction, chronic cardiac failure, dilatative car diopathy, chronic atrial fibrillation, valvular disease, chronic obstructiv e pulmonary disease, chronic cor pulmonale, malignancy, chronic renal failu re). Time of symptom onset of each event was recorded accurately, then tabu lated into 24 increments of Ih (e.g., 06:00 to 06:59 was reported as 6 A.M. ). For statistical chronobiological analysis, partial Fourier series were u sed. Results. During the 7-year period, 1321 consecutive cases of APE in 10 14 different subjects were observed. The majority of events occurred at nig ht, and statistical analysis showed a 24h rhythmicity both in the total sam ple population and in all considered subgroups, with the only exception bei ng patients with pulmonary embolism and arrhythmias, for which the small nu mber of cases made the study of rhythms in APE impossible. Conclusions. The nighttime preference in the occurrence of APE appears to be quite independ ent of all demographic features or underlying pathophysiological causes.