title: Treatment of orthostatic tachycardia with erythropoietin.
abstract: OBJECTIVE
  To determine whether increasing red blood cell volume with erythropoietin reverses the hemodynamic response to standing in patients with orthostatic tachycardia.
  
  
  METHODS
  Eight patients (2 men, 6 women) with orthostatic tachycardia were administered erythropoietin (50 U/kg body weight 3 times a week for 6 to 12 weeks) in order to reverse their red blood cell volume deficit. Six of the patients also received fludrocortisone (0.1 mg/d). Plasma and red blood cell volumes as well as the hemodynamic response to orthostatic stress were measured before and after erythropoietin therapy.
  
  
  RESULTS
  Erythropoietin therapy increased the mean +/- hematocrit from 37.6 +/- 1.0 to 46.4 +/- 1.4 (+/- standard error) (P < 0.01) and increased the red blood cell volume from 17.7 +/- 1.1 to 24.6 +/- 2.0 mL/kg (P < 0.01). Treatment increased supine mean blood pressure (from 87 +/- 4 to 93 +/- 5 mm Hg, P < 0.025) and standing mean blood pressure (from 87 +/- 4 to 94 +/- 5 mm Hg, P < 0.025). Erythropoietin therapy, however, failed to reverse orthostatic tachycardia. Following treatment, the mean heart rate after 5 minutes standing was 129 +/- 7 bpm, not significantly different from the pretreatment standing heart rate (134 +/- 5 bpm).
  
  
  CONCLUSIONS
  Although patients with the orthostatic tachycardia syndrome have a deficit in red blood cell volume, this is not the cause of their abnormal hemodynamic response to standing. Erythropoietin therapy fails to reverse orthostatic tachycardia.
mesh_terms: D000328:Adult; D000368:Aged; D001810:Blood Volume; D004921:Erythropoietin / Q000627:therapeutic use*; D005260:Female; D006400:Hematocrit; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture; D013610:Tachycardia / Q000097:blood / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D017211:Treatment Failure
chemical_list: D004921:Erythropoietin