title: Effect of essential hypertension on cardiac autonomic function in type 2 diabetic patients.
abstract: OBJECTIVE
  The aim of this study was to examine the effects of essential hypertension on cardiac autonomic function in type 2 diabetic patients.
  
  
  BACKGROUND
  Hypertension is common in type 2 diabetic patients and is associated with a high mortality. However, the combined effects of type 2 diabetes and essential hypertension on cardiac autonomic function have not been fully elucidated.
  
  
  METHODS
  Thirty-three patients with type 2 diabetes were assigned to a hypertensive diabetic group (n = 15; age: 56 +/- 8 years, mean +/- SD) or an age-matched normotensive diabetic group (n = 18, 56 +/- 6 years). Cardiac autonomic function was assessed by baroreflex sensitivity (BRS), heart rate variability (HRV), plasma norepinephrine concentration and cardiac 123I-metaiodobenzylguanidine (MIBG) scintigraphic findings.
  
  
  RESULTS
  Baroreflex sensitivity was lower in the hypertensive diabetic group than it was in the normotensive diabetic group (p < 0.05). The early and delayed myocardial uptake of 123I-MIBG was lower (p < 0.01 and p < 0.05, respectively), and the percent washout rate of 123I-MIBG was higher (p < 0.05) in the hypertensive diabetic group. However, the high frequency (HF) power and the ratio of low frequency (LF) power to HF power (LF/HF) of HRV and plasma norepinephrine concentration were not significantly different. The homeostasis model assessment index was higher in the hypertensive diabetic group than it was in the normotensive diabetic group (p < 0.01).
  
  
  CONCLUSIONS
  Our results indicate that essential hypertension acts synergistically with type 2 diabetes to depress cardiac reflex vagal and sympathetic function, and the results also suggest that insulin resistance may play a pathogenic role in these processes.
authors.affiliation: Department of Internal Medicine I, School of Medicine, Oita Medical University, Japan. takanao@oita-med.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Nakagawa
authors.forename: T
authors.initials: T
authors.lastname: Saikawa
authors.forename: T
authors.initials: T
authors.lastname: Ooie
authors.forename: K
authors.initials: K
authors.lastname: Yufu
authors.forename: S
authors.initials: S
authors.lastname: Shigematsu
authors.forename: M
authors.initials: M
authors.lastname: Hara
authors.forename: H
authors.initials: H
authors.lastname: Sakino
authors.forename: I
authors.initials: I
authors.lastname: Katsuragi
authors.forename: T
authors.initials: T
authors.lastname: Okeda
authors.forename: H
authors.initials: H
authors.lastname: Yoshimatsu
authors.forename: T
authors.initials: T
authors.lastname: Sakata
mesh_terms: D019797:3-Iodobenzylguanidine; D001341:Autonomic Nervous System / Q000503:physiopathology*; D017704:Baroreflex / Q000502:physiology; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000503:physiopathology*; D005260:Female; D006321:Heart / Q000294:innervation*; D006334:Heart Function Tests; D006339:Heart Rate; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D019275:Radiopharmaceuticals
chemical_list: D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine; D009638:Norepinephrine