title: Early heart rate recovery after exercise predicts mortality in patients with chronic heart failure.
abstract: BACKGROUND
  Patients with chronic heart failure (CHF) have multiple abnormalities of autonomic regulation that have been associated to their high mortality rate. Heart rate recovery immediately after exercise is an index of parasympathetic activity, but its prognostic role in CHF patients has not been determined yet.
  
  
  METHODS
  Ninety-two stable CHF patients (83M/9F, mean age: 51+/-12 years) performed an incremental symptom-limited cardiopulmonary exercise testing. Measurements included peak O2 uptake (VO2p), ventilatory response to exercise (VE/VCO2 slope), the first-degree slope of VO2 for the 1st minute of recovery (VO2/t-slope), heart rate recovery [(HRR1, bpm): HR difference from peak to 1 min after exercise] and chronotropic response to exercise [%chronotropic reserve (CR, %)=(peak HR-resting HR/220-age-resting HR)x100]. Left ventricular ejection fraction (LVEF, %) was also measured by radionuclide ventriculography.
  
  
  RESULTS
  Fatal events occurred in 24 patients (26%) during 21+/-6 months of follow-up. HRR1 was lower in non-survivors (11.4+/-6.4 vs. 20.4+/-8.1; p<0.001). All cause-mortality rate was 65% in patients with HRR1<or=12 bpm versus 11% in patients with HRR1>12 bpm (log-rank: 32.6; p<0.001). By multivariate survival analysis, HRR1 resulted as an independent predictor of mortality (chi2=19.2; odds ratio: 0.87; p<0.001) after adjustment for LVEF, VO2p, VE/VCO2 slope, CR and VO2/t-slope. In a subgroup of patients with intermediate exercise capacity (VO2p: 10-18, ml/kg/min), HRR1 was a strong predictor of mortality (chi2: 14.3; odds ratio: 0.8; p<0.001).
  
  
  CONCLUSIONS
  Early heart rate recovery is an independent prognostic risk indicator in CHF patients and could be used in CHF risk stratification.
authors.affiliation: Pulmonary and Critical Care Medicine Department, Cardiopulmonary Exercise Testing and Rehabilitation Laboratory, Evgenidio Hospital, National and Kapodestrian University of Athens, 20, Papadiamantopoulou str, Athens, 11528, Greece. snanas@cc.uoa.gr
authors.forename: Serafim
authors.initials: S
authors.lastname: Nanas
authors.forename: Maria
authors.initials: M
authors.lastname: Anastasiou-Nana
authors.forename: Stavros
authors.initials: S
authors.lastname: Dimopoulos
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Sakellariou
authors.forename: George
authors.initials: G
authors.lastname: Alexopoulos
authors.forename: Smaragdo
authors.initials: S
authors.lastname: Kapsimalakou
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Papazoglou
authors.forename: Elias
authors.initials: E
authors.lastname: Tsolakis
authors.forename: Ourania
authors.initials: O
authors.lastname: Papazachou
authors.forename: Charis
authors.initials: C
authors.lastname: Roussos
authors.forename: John
authors.initials: J
authors.lastname: Nanas
mesh_terms: D002908:Chronic Disease; D015444:Exercise / Q000502:physiology*; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000401:mortality*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008168:Lung / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012372:ROC Curve; D012307:Risk Factors; D015996:Survival Rate; D013997:Time Factors