title: Predictors of abnormal heart rate recovery in patients with heart failure reduced and preserved ejection fraction.
abstract: BACKGROUND
  Heart rate recovery (HRR) is becoming an important prognostic maker in heart failure (HF), but very little is known about the underlying mechanisms responsible for its clinical efficacy. Therefore, we examined echocardiographic and exercise (submaximal and maximal) characteristics to gain a better appreciation of HRR and factors responsible for the development of abnormal HRR in patients with both heart failure reduced ejection fraction (HFrEF) and heart failure preserved ejection fraction (HFpEF).
  
  
  METHODS
  Cardiopulmonary exercise testing (CPX), a 6-minute walk test (6MWT), and resting 2D echocardiography were randomly performed in 240 HF patients (200 HFrEF, 40 HFpEF) after which HRR was measured. HRR was defined as the difference between heart rate at peak exercise and 1 minute following test termination.
  
  
  RESULTS
  Bivariate correlation analyses found significant relationships among most CPX and 6MWT measurements with the highest correlations between 6MWT HRR and 6MWT peak HR (r = 0.65; p < 0.001) and CPX HRR and CPX HRreserve (r = 0.63; p < 0.001). The relationship between 6MWT HRR and CPX HRR was very good (r = 0.91; p < 001). Multivariate logistic regression of submaximal and maximal exercise found 6MWT peak HR and exercise oscillatory ventilation (EOV), respectively, were the strongest predictors (p < 0.001) of abnormal HRR. The E/E' was a significant predictor (p < 0.001) of abnormal HRR, but EOV was the strongest predictor of abnormal HRR (OR = 6.5).
  
  
  CONCLUSIONS
  HRR after both CPX and the 6MWT is significantly related to many exercise and echocardiographic measures with the most significant predictors of abnormal HRR being related to indices of cardiorespiratory performance in patients with HFrEF and HFpEF.
authors: University of Miami, Miami, FL, USA.
authors: Lawrence P
authors: LP
authors: Cahalin
authors: University of New Mexico School of Medicine, Albuquerque, NM, USA.
authors: Ross
authors: R
authors: Arena
authors: University of Milano, I.R.C.C.S. Policlinico San Donato, San Donato Milanese, Italy.
authors: Valentina
authors: V
authors: Labate
authors: University of Milano, I.R.C.C.S. Policlinico San Donato, San Donato Milanese, Italy.
authors: Francesco
authors: F
authors: Bandera
authors: University of Milano, I.R.C.C.S. Policlinico San Donato, San Donato Milanese, Italy marco.guazzi@unimi.it.
authors: Marco
authors: M
authors: Guazzi
mesh_terms: D000368:Aged; D004452:Echocardiography; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D013318:Stroke Volume / Q000502:physiology*; D018615:Ultrasonography, Doppler, Color
keywords: 6-minute walk test; Cardiopulmonary exercise testing; heart failure; heart rate recovery; prediction