title: Prevalence of orthostatic hypotension among patients presenting with syncope in the ED.
abstract: We sought to determine the prevalence of orthostatic hypotension as a cause of syncope in the emergency setting, and describe the characteristics of patients diagnosed with this condition. Blood pressure orthostatic changes were measured prospectively in a standardized fashion up to 10 minutes, or until symptoms occurred, in all consecutive patients with syncope as a chief complaint presenting in the emergency department (ED) of a primary and tertiary care hospital. Patients unable to stand-up were excluded. Hypotension was considered to be the cause of syncope when there was: (1) a decrease in systolic blood pressure (SBP) >or= 20 mm Hg with simultaneous symptoms; (2) a decrease in SBP between 10 and 20 mm Hg, but a SBP <or= 90 mm Hg with or without symptoms; and (3) a nonsignificant decrease in SBP in the ED, but a prehospital value <or= 80 mm Hg was documented that prompted fluid therapy before standardized measurements. Among 788 patients with syncope seen in the ED during a 20-month period, 650 were included in the study, and 579 (89%) had standardized measurements of SBP. According to diagnostic criteria, orthostatic hypotension was considered to be the cause of syncope in 156 of them (24%). Fifty-eight patients (37%) had drug-induced hypotension, 33 (21%) hypovolemia, 19 (12%) postprandial hypotension, and 46 (29%) idiopathic hypotension. Asymptomatic SBP changes >or= 20 mm Hg were found in 10% of patients with syncope attributed to other causes. Compared with patients with vasovagal disorder, those with orthostatic hypotension were older; had more comorbid conditions including hypertension, organic heart disease, and abnormal electrocardiogram; were taking more hypotensive medications; and required more frequently hospitalization (P <.01). We concluded that standardized blood pressure measurement in the ED enabled to strongly implicate orthostatic hypotension as a cause of syncope in 24% of patients with this symptom. Drug-related hypotension was the most frequent cause for this disorder.
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000009:adverse effects; D003937:Diagnosis, Differential; D004562:Electrocardiography; D004632:Emergency Medical Services; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007024:Hypotension, Orthostatic / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012008:Recurrence; D016019:Survival Analysis; D013557:Switzerland / Q000453:epidemiology; D013575:Syncope / Q000175:diagnosis* / Q000209:etiology
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors