title: Heart rate recovery predicts clinical worsening in patients with pulmonary arterial hypertension.
abstract: BACKGROUND
  Reduced heart rate recovery after exercise is associated with increased mortality in cardiopulmonary diseases.
  
  
  OBJECTIVE
  We sought to evaluate the association between heart rate recovery at 1 minute of rest (HRR1) after 6-min walk test (6MW test) and clinical worsening in patients with idiopathic pulmonary arterial hypertension (IPAH).
  
  
  METHODS
  HRR1 was defined as the difference in heart rate at the end of 6MW test and at 1 minute after completion of the 6MW test. Between August 1, 2009 and March 30, 2010, 75 consecutive patients with IPAH underwent 6MW test and were included in the analysis.
  
  
  RESULTS
  Compared with patients with HRR1 ≥ 16 (n = 45 [60%]), those with HRR1 less than 16 (n = 30 [40%]) were more likely to have clinical worsening (odds ratio, 9.7; 95% confidence interval [CI], 3-30; P < 0.001) and shorter time to first clinical worsening event (TCW) (6.7 mo vs. 13 mo; P < 0.001) during follow-up. By multivariable analysis, the best predictors of clinical worsening were HRR1 less than 16 (hazard ratio, 5.2; 95% CI, 1.8-14.8; P = 0.002) and mean pulmonary arterial pressure (hazard ratio, 1.04; 95% CI, 1.007-1.08; P = 0.02). Compared with the distance walked during the 6MW test (6MWD), HRR1 less than 16 was a better predictor of clinical worsening (C statistic 0.757 vs. 0.703) and TCW (C index 0.730 vs. 0.696). The addition of HRR1 increased the ability of 6MWD to predict clinical worsening events.
  
  
  CONCLUSIONS
  HRR1 after 6MW test is a strong predictor of clinical worsening and TCW in patients with IPAH. The addition of HRR1 to 6MWD increases the capacity of 6MWD to predict clinical worsening and TCW in patients with IPAH.
authors: Department of Pulmonary, Allergy, and Critical Care Medicine, Respiratory Institute, Cleveland Clinic, Cleveland, OH 44195, USA. minaio@ccf.org
authors: Omar A
authors: OA
authors: Minai
authors: Ravi
authors: R
authors: Gudavalli
authors: Srinivas
authors: S
authors: Mummadi
authors: Xiaobo
authors: X
authors: Liu
authors: Kevin
authors: K
authors: McCarthy
authors: Raed A
authors: RA
authors: Dweik
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers; D018450:Disease Progression; D005080:Exercise Test; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000401:mortality / Q000503:physiopathology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis; D016138:Walking
chemical_list: D015415:Biomarkers