title: Heart rate recovery in pulmonary arterial hypertension: relationship with exercise capacity and prognosis.
abstract: BACKGROUND
  Delayed postexercise heart rate recovery (HRR) has been associated with disability and poor prognosis in chronic cardiopulmonary diseases. The usefulness of HRR to predict exercise impairment and mortality in patients with pulmonary arterial hypertension (PAH), however, remains largely unexplored.
  
  
  METHODS
  Seventy-two patients with PAH of varied etiology (New York Heart Association classes I-IV) and 21 age- and gender-matched controls underwent a maximal incremental cardiopulmonary exercise test (CPET), with heart rate being recorded up to the fifth minute of recovery.
  
  
  RESULTS
  Heart rate recovery was consistently lower in the patients compared with the controls (P < .05). The best cutoff for HRR in 1 minute (HRR(1 min)) to discriminate the patients from the controls was 18 beats. Compared with patients with HRR(1 min) ≤ 18 (n = 40), those with HRR(1 min) >18 (n = 32) had better New York Heart Association scores, resting hemodynamics and 6-minute walking distance. In fact, HRR(1 min) >18 was associated with a range of maximal and submaximal CPET variables indicative of less severe exercise impairment (P < .05). The single independent predictor of HRR(1 min) ≤ 18 was the 6-minute walking distance (odds ratio [95% CI] 0.99 [0.98-1.00], P < .05). On a multiple regression analysis that considered only CPET-independent variables, HRR(1 min) ≤ 18 was the single predictor of mortality (hazard ratio [95% CI] 1.19 [1.03-1.37], P < .05).
  
  
  CONCLUSIONS
  Preserved HRR(1 min) (>18 beats) is associated with less impaired responses to incremental exercise in patients with PAH. Conversely, a delayed HRR(1 min) response has negative prognostic implications, a finding likely to be clinically useful when more sophisticated (and costlier) analyses provided by a full CPET are not available.
authors.affiliation: Division of Respiratory Diseases, Department of Medicine, São Paulo School of Medicine (EPM), Federal University of Sao Paulo (UNIFESP), Sao Paulo, SP, Brazil.
authors.forename: Roberta P
authors.initials: RP
authors.lastname: Ramos
authors.forename: Jaquelina S O
authors.initials: JS
authors.lastname: Arakaki
authors.forename: Priscila
authors.initials: P
authors.lastname: Barbosa
authors.forename: Erika
authors.initials: E
authors.lastname: Treptow
authors.forename: Fabricio M
authors.initials: FM
authors.lastname: Valois
authors.forename: Eloara V M
authors.initials: EV
authors.lastname: Ferreira
authors.forename: Luiz Eduardo
authors.initials: LE
authors.lastname: Nery
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Neder
mesh_terms: D000328:Adult; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006339:Heart Rate; D006801:Humans; D006976:Hypertension, Pulmonary / Q000401:mortality / Q000503:physiopathology*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011379:Prognosis