title: Autonomic control during acute hypoglycemia in type 1 diabetes mellitus.
abstract: OBJECTIVE
  We hypothesized that adults with type 1 diabetes mellitus (T1DM) would exhibit impaired heart rate variability (HRV), QT interval, T-wave amplitude, and baroreflex sensitivity (BRS) when compared with healthy controls. In addition, we hypothesized that acute hypoglycemia would result in further adverse changes in measures of autonomic and cardiovascular function.
  
  
  METHODS
  A single 180-min hyperinsulinemic (2 mU/kg TBW/min), hypoglycemic (~3.3 umol/mL) clamp was completed in 10 healthy adults and 13 adults with T1DM. Counterregulatory hormones were assessed and measures of heart rate (electrocardiogram) and blood pressure (intra-arterial catheter or finger photoplethysmography) were analyzed at baseline and during the hypoglycemic clamp for measures of HRV, QT interval, T-wave amplitude, and spontaneous cardiac BRS (sCBRS).
  
  
  RESULTS
  Baseline measures of HRV, sCBRS, and T-wave amplitude were blunted in adults with T1DM when compared with healthy controls. Hypoglycemia resulted in significant reductions in HRV, sCBRS, and T-wave amplitude and prolonged QT intervals; these changes were not different between adults with T1DM and healthy controls.
  
  
  CONCLUSIONS
  Results from the current study show that adults with T1DM exhibit impaired autonomic and cardiovascular function. Additionally, novel findings highlight an effect of acute hypoglycemia to further reduce measures of autonomic and cardiovascular function similarly between adults with T1DM and healthy controls. These results suggest that acute hypoglycemia may worsen impairments in autonomic and cardiovascular control in patients with T1DM, thus increasing the risk of ventricular arrhythmias and cardiovascular mortality.
authors.affiliation: Department of Anesthesiology, Mayo Clinic, 200 1st St SW, Rochester, MN, 55905, USA, Limberg.Jacqueline@Mayo.edu.
authors.forename: Jacqueline K
authors.initials: JK
authors.lastname: Limberg
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Farni
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Taylor
authors.forename: Simmi
authors.initials: S
authors.lastname: Dube
authors.forename: Ananda
authors.initials: A
authors.lastname: Basu
authors.forename: Rita
authors.initials: R
authors.lastname: Basu
authors.forename: Erica A
authors.initials: EA
authors.lastname: Wehrwein
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Joyner
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D017704:Baroreflex / Q000502:physiology; D002319:Cardiovascular System / Q000503:physiopathology; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D055815:Young Adult