title: Complexity of heart rate variability predicts outcome in intensive care unit admitted patients with acute stroke .
abstract: BACKGROUND
  Heart rate variability (HRV) has been proposed as a predictor of acute stroke outcome. This study aimed to evaluate the predictive value of a novel non-linear method for analysis of HRV, multiscale entropy (MSE) and outcome of patients with acute stroke who had been admitted to the intensive care unit (ICU).
  
  
  METHODS
  The MSE of HRV was analysed from 1 h continuous ECG signals in ICU-admitted patients with acute stroke and controls. The complexity index was defined as the area under the MSE curve (scale 1-20). A favourable outcome was defined as modified Rankin scale 0-2 at 3 months after stroke.
  
  
  RESULTS
  The trends of MSE curves in patients with atrial fibrillation (AF) (n=77) were apparently different from those in patients with non-AF stroke (n=150) and controls (n=60). In addition, the values of complexity index were significantly lower in the patients with non-AF stroke than in the controls (25.8±.3 vs. 32.3±4.3, p<0.001). After adjustment for clinical variables, patients without AF who had a favourable outcome were significantly related to higher complexity index values (OR=1.15, 95% CI 1.07 to 1.25, p<0.001). Importantly, the area under the receiver operating characteristic curve for predicting a favourable outcome of patients with non-AF stroke from clinical parameters was 0.858 (95% CI 0.797 to 0.919) and significantly improved to 0.903 (95% CI 0.853 to 0.954) after adding on the parameter of complexity index values (p=0.020).
  
  
  CONCLUSIONS
  In ICU-admitted patients with acute stroke, early assessment of the complexity of HRV by MSE can help in predicting outcomes in patients without AF.
authors: Stroke Center and Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan NTU-NTUH-MediaTek Innovative Medical Electronics Research Center, Taipei, Taiwan.
authors: Sung-Chun
authors: SC
authors: Tang
authors: NTU-NTUH-MediaTek Innovative Medical Electronics Research Center, Taipei, Taiwan Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan.
authors: Hsiao-I
authors: HI
authors: Jen
authors: NTU-NTUH-MediaTek Innovative Medical Electronics Research Center, Taipei, Taiwan Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors: Yen-Hung
authors: YH
authors: Lin
authors: NTU-NTUH-MediaTek Innovative Medical Electronics Research Center, Taipei, Taiwan Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors: Chi-Sheng
authors: CS
authors: Hung
authors: NTU-NTUH-MediaTek Innovative Medical Electronics Research Center, Taipei, Taiwan Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan.
authors: Wei-Jung
authors: WJ
authors: Jou
authors: NTU-NTUH-MediaTek Innovative Medical Electronics Research Center, Taipei, Taiwan Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan.
authors: Pei-Wen
authors: PW
authors: Huang
authors: Department of Mechanical Engineering, Yuan Ze University, Tao-Yuan, Taiwan.
authors: Jiann-Shing
authors: JS
authors: Shieh
authors: NTU-NTUH-MediaTek Innovative Medical Electronics Research Center, Taipei, Taiwan Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors: Yi-Lwun
authors: YL
authors: Ho
authors: NTU-NTUH-MediaTek Innovative Medical Electronics Research Center, Taipei, Taiwan Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.
authors: Dar-Ming
authors: DM
authors: Lai
authors: NTU-NTUH-MediaTek Innovative Medical Electronics Research Center, Taipei, Taiwan Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan.
authors: An-Yeu
authors: AY
authors: Wu
authors: Stroke Center and Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.
authors: Jiann-Shing
authors: JS
authors: Jeng
authors: NTU-NTUH-MediaTek Innovative Medical Electronics Research Center, Taipei, Taiwan Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors: Ming-Fong
authors: MF
authors: Chen
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications / Q000503:physiopathology; D016022:Case-Control Studies; D004562:Electrocardiography; D019277:Entropy; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D017063:Outcome Assessment, Health Care; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000503:physiopathology*
keywords: AUTONOMIC; INTENSIVE CARE; STROKE