title: Sympathetic overactivity and sudden cardiac death among hemodialysis patients with left ventricular hypertrophy.
abstract: BACKGROUND
  We prospectively investigated whether cardiac autonomic imbalance is associated with sudden cardiac death (SCD) among a group of hemodialysis patients with left ventricular hypertrophy (LVH).
  
  
  METHODS
  In a prospective cohort study, we enrolled 196 asymptomatic patients on chronic hemodialysis who had LVH as determined by echocardiography and had undergone twenty-four-hour ambulatory Holter electrocardiography between dialysis sessions (males/females, 114/82; mean age, 65+/-12 years) to analyze heart rate variability. We calculated the percentage difference between adjacent NN intervals more than 50 ms (pNN50) and high-frequency component (HF, 0.15-0.40 Hz) as parameters of cardiac parasympathetic activity, and the low-frequency component (LF, 0.04-0.15 Hz)/HF component ratio as a parameter of sympathetic activity.
  
  
  RESULTS
  During 4.5+/-1.9-year follow-up, 21 patients who had undergone coronary revascularization within 60 days of enrollment were excluded from the analysis. Among the remaining 175 patients (male/female, 105/70; 66+/-12 years), SCD was recognized in 23 patients. On stepwise Cox hazard analysis, SCD was positively associated with age and LF/HF ratio, and tended to be inversely associated with pNN50. On Kaplan-Meier analysis, SCD-free survival rates at 5 years were 29.4% and 98.1% in patients with LF/HF ratios of 1.9 or more and below 1.9, respectively.
  
  
  CONCLUSIONS
  The presence of cardiac sympathetic overactivity may predict the occurrence of SCD in the asymptomatic hemodialysis patients with LVH.
authors.affiliation: Cardiovascular Division, Toujinkai Hospital, Kyoto, Japan. mnishimura@tea.ocn.ne.jp
authors.forename: Masato
authors.initials: M
authors.lastname: Nishimura
authors.forename: Toshiko
authors.initials: T
authors.lastname: Tokoro
authors.forename: Masasya
authors.initials: M
authors.lastname: Nishida
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Satoru
authors.initials: S
authors.lastname: Yamazaki
authors.forename: Ryo
authors.initials: R
authors.lastname: Imai
authors.forename: Koji
authors.initials: K
authors.lastname: Okino
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Iwamoto
authors.forename: Hakuo
authors.initials: H
authors.lastname: Takahashi
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Ono
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001342:Autonomic Nervous System Diseases / Q000150:complications / Q000401:mortality / Q000503:physiopathology; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac / Q000209:etiology* / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000150:complications / Q000401:mortality* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis / Q000009:adverse effects / Q000401:mortality* / Q000639:trends