title: Clinical improvement in patients with orthostatic intolerance after treatment with bisoprolol and fludrocortisone.
abstract: Orthostatic intolerance is the development of disabling symptoms upon assuming an upright posture that are relieved partially by resuming the supine position. Postural tachycardia syndrome (POTS) is an orthostatic intolerance syndrome characterized by palpitations because of excessive orthostatic sinus tachycardia, lightheadedness, tremor, and near-syncope. Patients usually undergo extensive medical, cardiac, endocrine, neurologic, and psychiatric evaluation, which usually fails to identify a specific abnormality. The authors investigated the autonomic and hemodynamic profile of patients with POTS and the effectiveness of bisoprolol and fludrocortisone. The authors evaluated 11 female patients with POTS before and after medical treatment with a cardioselective bisoprolol beta-blocker or fludrocortisone, or both, and 11 age-matched control patients. Variability of heart rate and systolic blood pressure was assessed by fast Fourier transform, and spontaneous baroreceptor gain was assessed by use of the temporal sequences slope and alpha index. Modelflow was used to quantify hemodynamics. Symptoms in all patients improved greatly after medication. The autonomic and hemodynamic impairment observed in patients with POTS, particularly after orthostatic stress, is treated effectively with bisoprolol or fludrocortisone or both. These results need further confirmation in a controlled double-blind study. Proper medical treatment improves dramatically the clinical and autonomic-hemodynamic disturbances observed in patients with POTS. The data support the hypothesis that POTS is the result of a hyperadrenergic activation or hypovolemia during orthostasis.
authors.affiliation: Centro de Estudos da Função Autonómica do Hospital de São João do Porto, Portugal. jfreitas@med.up.pt
authors.forename: J
authors.initials: J
authors.lastname: Freitas
authors.forename: R
authors.initials: R
authors.lastname: Santos
authors.forename: E
authors.initials: E
authors.lastname: Azevedo
authors.forename: O
authors.initials: O
authors.lastname: Costa
authors.forename: M
authors.initials: M
authors.lastname: Carvalho
authors.forename: A F
authors.initials: AF
authors.lastname: de Freitas
mesh_terms: D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D017298:Bisoprolol / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D004562:Electrocardiography; D005260:Female; D005438:Fludrocortisone / Q000627:therapeutic use*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007024:Hypotension, Orthostatic / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D008875:Middle Aged; D008901:Mineralocorticoids / Q000627:therapeutic use; D011187:Posture; D011311:Pressoreceptors / Q000187:drug effects; D013565:Sympatholytics / Q000627:therapeutic use; D013577:Syndrome; D013610:Tachycardia / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D018667:Tilt-Table Test; D016896:Treatment Outcome
chemical_list: D000319:Adrenergic beta-Antagonists; D008901:Mineralocorticoids; D013565:Sympatholytics; D005438:Fludrocortisone; D017298:Bisoprolol