title: Simultaneous heart rate variability monitoring enhances the predictive value of flow-mediated dilation in ischemic heart disease.
abstract: BACKGROUND
  Endothelial dysfunction and autonomic nervous system imbalance are both risk markers of atherosclerotic vascular damage. The relationship between these 2 factors, however, has not been clarified concisely.
  
  
  RESULTS
  Flow-mediated dilation (FMD) was measured in 47 patients with ischemic heart disease (IHD; mean age, 68.1±7.1 years) using an ultrasound semi-automatic measuring system (UNEXEF18G), and autonomic nervous system activity was evaluated by simultaneous measurements of heart rate variability. FMD was significantly correlated with standard deviation of normal-to-normal beats (r=0.33, P=0.022) and the power ratio of low-frequency power to high-frequency power (LF/HF; r=-0.38, P=0.0087). Furthermore, multiple regression analysis indicated that LF/HF was the most important predictor of the magnitude of FMD. This interaction was severely blunted by β-blockers and the presence of diabetes. Moreover, standardized FMD according to autonomic nervous system activity was a better predictor of future cardiovascular events than FMD. Subjects with cardiovascular events had a significantly smaller corrected FMD (event (+), 3.62±0.41; event (-), 5.10±2.35; P=0.001), and the higher corrected FMD was associated with longer event-free survival.
  
  
  CONCLUSIONS
  Autonomic nervous system activity is an important regulatory factor of FMD in subjects with IHD. Assessment of this interaction can help provide more accurate risk stratification of subjects with IHD.
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Watanabe
authors.forename: Eisuke
authors.initials: E
authors.lastname: Amiya
authors.forename: Masafumi
authors.initials: M
authors.lastname: Watanabe
authors.forename: Munenori
authors.initials: M
authors.lastname: Takata
authors.forename: Atsuko
authors.initials: A
authors.lastname: Ozeki
authors.forename: Aya
authors.initials: A
authors.lastname: Watanabe
authors.forename: Shuichi
authors.initials: S
authors.lastname: Kawarasaki
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nakao
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Hosoya
authors.forename: Kazuko
authors.initials: K
authors.lastname: Omori
authors.forename: Koji
authors.initials: K
authors.lastname: Maemura
authors.forename: Issei
authors.initials: I
authors.lastname: Komuro
authors.forename: Ryozo
authors.initials: R
authors.lastname: Nagai
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000368:Aged; D001341:Autonomic Nervous System / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D048909:Diabetes Complications / Q000503:physiopathology; D018572:Disease-Free Survival; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000401:mortality / Q000503:physiopathology*; D012189:Retrospective Studies; D015996:Survival Rate; D014463:Ultrasonography
chemical_list: D000319:Adrenergic beta-Antagonists