title: Heart rate recovery is an important predictor of outcomes in patients with connective tissue disease-associated pulmonary hypertension.
abstract: Reduced heart rate recovery (HRR) after exercise is associated with increased mortality in cardiac and pulmonary diseases. We sought to evaluate the association between HRR after the 6-minute walk test (6MWT) and outcomes in patients with connective tissue disease-associated pulmonary hypertension (CTD-PH). Data were obtained by review of the medical records. HRR was defined as the difference in heart rate at the end of the 6MWT and after 1 minute (HRR1), 2 minutes (HRR2), and 3 minutes (HRR3) of rest. All patients with pulmonary hypertension and a diagnosis of systemic sclerosis, systemic lupus erythematosus, or mixed connective tissue disease who underwent the 6MWT between August 1, 2009, and October 30, 2011, were included (n = 66). By Kaplan-Meier analysis, HRR1, HRR2, and HRR3 at different cutoff points were all good predictors, with HRR1 of <16 being the best predictor of time to clinical worsening (log-rank P < 0.0001), hospitalization (log-rank P = 0.0001), and survival (log-rank P < 0.003). By proportional hazards regression, patients with HRR1 of <16 were at increased risk of clinical worsening (hazard ratio [HR]: 6.4 [95% confidence interval (CI): 2.6-19.2]; P < 0.0001], hospitalization (HR: 6.6 [95% CI: 2.4-23]; P < 0.0001), and death (HR: 4.5 [95% CI: 1.6-15.7]; P = 0.003). Patients in the highest tercile (HRR1 of ≥19) were unlikely to have a clinical worsening event (HR: 0.1 [95% CI: 0.04-0.5]; P = 0.001], to be hospitalized (HR: 0.1 [95% CI: 0.02-0.5]; P = 0.001), or to die (HR: 0.3 [95% CI: 0.07-0.9]; P = 0.04]. In conclusion, in patients with CTD-PH, abnormal HRR1 (defined as HRR1 of <16) after the 6MWT is a strong predictor of clinical worsening, time to clinical worsening, survival, and hospitalization.
authors.affiliation: Department of Pulmonary, Allergy, and Critical Care Medicine, Respiratory Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Omar A
authors.initials: OA
authors.lastname: Minai
authors.affiliation: Department of Medicine, Medicine Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Quyen
authors.initials: Q
authors.lastname: Nguyen
authors.affiliation: Department of Pulmonary Medicine, Oregon Health and Science University, Portland, Oregon, USA.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Mummadi
authors.affiliation: Department of Qualitative Health Sciences, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Esteban
authors.initials: E
authors.lastname: Walker
authors.affiliation: Department of Pulmonary, Allergy, and Critical Care Medicine, Respiratory Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: McCarthy
authors.affiliation: Department of Pulmonary, Allergy, and Critical Care Medicine, Respiratory Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Raed A
authors.initials: RA
authors.lastname: Dweik
keywords: 6-minute walk test; heart rate; pulmonary hypertension; scleroderma; survival