title: Resting heart rate and heart rate reserve in advanced heart failure have distinct pathophysiologic correlates and prognostic impact: a prospective pilot study.
abstract: OBJECTIVE
  The purpose of this study was to compare the prognostic impact of clinical and biomarker correlates of resting heart rate (HR) and chronotropic incompetence in heart failure (HF) patients.
  
  
  BACKGROUND
  The mechanisms and underlying pathophysiological influences of HR abnormalities in HF are incompletely understood.
  
  
  METHODS
  In a prospective pilot study, 81 patients with advanced systolic HF (97% were receiving beta-blockers) and 25 age-, sex-, and body-size matched healthy controls underwent maximal cardiopulmonary exercise testing with sampling of neurohormones and biomarkers.
  
  
  RESULTS
  Two-thirds of HF patients met criteria for chronotropic incompetence. Resting HR and HR reserve (HRR, a measure of chronotropic response) were not correlated with each other and were associated with distinct biomarker profiles. Resting HR correlated with increased myocardial stress (B-type natriuretic peptide [BNP]: r = 0.26; pro-A-type natriuretic peptide: r = 0.24; N-terminal-proBNP: r = 0.32) and inflammation (leukocyte count: r = 0.28; high-sensitivity C-reactive protein assay: r = 0.25). In contrast, HRR correlated with the neurohumoral response to HF (copeptin: r = -0.33; norepinephrine: r = -0.29) but not with myocyte stress or injury reflected by natriuretic peptides or hs-troponin I. Patients in the lowest chronotropic incompetence quartile (HRR ≤0.38) displayed more advanced HF, reduced exercise capacity, ventilatory inefficiency, and poorer quality of life. Over a median follow-up of 17 months, the combined endpoint of death or urgent transplant/assist device implantation occurred more frequently in patients with higher resting HR (>67 beats/min) or lower HRR, with both markers providing additive prognostic information.
  
  
  CONCLUSIONS
  Increased resting HR and chronotropic incompetence may reflect different pathophysiological processes, provide incremental prognostic information, and represent distinct therapeutic targets.
authors.affiliation: Department of Cardiology, Institute of Clinical and Experimental Medicine-IKEM, Prague, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Benes
authors.affiliation: Department of Cardiology, Institute of Clinical and Experimental Medicine-IKEM, Prague, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Kotrc
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota.
authors.forename: Barry A
authors.initials: BA
authors.lastname: Borlaug
authors.affiliation: Department of Cardiology, Institute of Clinical and Experimental Medicine-IKEM, Prague, Czech Republic.
authors.forename: Katerina
authors.initials: K
authors.lastname: Lefflerova
authors.affiliation: Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Petr
authors.initials: P
authors.lastname: Jarolim
authors.affiliation: Institute of Endocrinology, Prague, Czech Republic.
authors.forename: Bela
authors.initials: B
authors.lastname: Bendlova
authors.affiliation: Department of Cardiology, Institute of Clinical and Experimental Medicine-IKEM, Prague, Czech Republic.
authors.forename: Antonin
authors.initials: A
authors.lastname: Jabor
authors.affiliation: Department of Cardiology, Institute of Clinical and Experimental Medicine-IKEM, Prague, Czech Republic.
authors.forename: Josef
authors.initials: J
authors.lastname: Kautzner
authors.affiliation: Department of Cardiology, Institute of Clinical and Experimental Medicine-IKEM, Prague, Czech Republic; Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota. Electronic address: vojtech.melenovsky@ikem.cz.
authors.forename: Vojtech
authors.initials: V
authors.lastname: Melenovsky
mesh_terms: D002908:Chronic Disease; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011379:Prognosis; D011446:Prospective Studies; D012146:Rest; D012720:Severity of Illness Index
keywords: biomarkers; chronotropic incompetence; exercise; heart failure; heart rate