title: Characterization of exercise limitations by evaluating individual cardiac output patterns: a prospective cohort study in patients with chronic heart failure.
abstract: BACKGROUND
  Patients with chronic heart failure (CHF) suffer from exercise intolerance due to impaired central hemodynamics and subsequent alterations in peripheral skeletal muscle function and structure. The relative contribution of central versus peripheral factors in the reduced exercise capacity is still subject of debate. The main purpose was to investigate heterogeneity in the nature of exercise intolerance by evaluating individual cardiac output (Q) patterns. The secondary purpose was to evaluate whether patient and disease characteristics were associated with a central hemodynamic exercise limitation.
  
  
  METHODS
  Sixty-four stable CHF patients performed a symptom limited incremental exercise test with respiratory gas analysis and simultaneous assessment of Q, using a radial artery pulse contour analysis method. A central hemodynamic exercise limitation was defined as a plateau or decline in Q from 90 to 100 % of exercise duration.
  
  
  RESULTS
  Data from 61 patients were analyzed. A central hemodynamic exercise limitation was observed in 21 patients (34 %). In these patients, a higher occurrence of a plateau/decrease in oxygen uptake (VO2) (52 % vs 23 %, p = 0.02), stroke volume (SV) (100 % vs. 75 %, p = 0.01) and chronotropic incompetence (31 % vs. 2.5 %, p = 0.01) was observed, while presence of a left bundle branch block (LBBB) occurred significantly less (19 % vs 48 %, p = 0.03) There was no difference in disease characteristics such as etiology, duration, NYHA class, mitral regurgitation or ischemia.
  
  
  CONCLUSIONS
  The study revealed considerable heterogeneity in the nature of exercise limitations between moderately impaired CHF patients. In one third of the study population a plateau or decrease in Q towards peak exercise was demonstrated, which is indicative of a central hemodynamic exercise limitation. A central hemodynamic exercise limitation was associated with an impairment to augment stroke volume and heart rate.
authors.affiliation: Department of Cardiology, Máxima Medical Centre, De Run 4600, P.O. Box 7777, Veldhoven, 5500 MB, The Netherlands. r.spee@mmc.nl.
authors.forename: Ruud F
authors.initials: RF
authors.lastname: Spee
authors.affiliation: Department of Cardiology, Máxima Medical Centre, De Run 4600, P.O. Box 7777, Veldhoven, 5500 MB, The Netherlands. v.niemeijer@gmail.com.
authors.forename: Victor M
authors.initials: VM
authors.lastname: Niemeijer
authors.affiliation: Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands. b.wessels@tue.nll.
authors.forename: Bart
authors.initials: B
authors.lastname: Wessels
authors.affiliation: Department of Clinical Physics and Clinical Informatics, Máxima Medical Centre Veldhoven, Veldhoven, The Netherlands. j.jansen@mmc.nl.
authors.forename: Jasper P
authors.initials: JP
authors.lastname: Jansen
authors.affiliation: Department of Clinical Physics and Clinical Informatics, Máxima Medical Centre Veldhoven, Veldhoven, The Netherlands. p.wijn@mmc.nl.|Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands. p.wijn@mmc.nl.
authors.forename: Pieter F F
authors.initials: PF
authors.lastname: Wijn
authors.affiliation: Department of Cardiology, University Medical Centre Utrecht, Utrecht, The Netherlands. p.doevendans@umcutrecht.nl.
authors.forename: Pieter A F M
authors.initials: PA
authors.lastname: Doevendans
authors.affiliation: Department of Cardiology, Máxima Medical Centre, De Run 4600, P.O. Box 7777, Veldhoven, 5500 MB, The Netherlands. h.kemps@mmc.nl.|Department of Medical Informatics, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands. h.kemps@mmc.nl.
authors.forename: Hareld M C
authors.initials: HM
authors.lastname: Kemps
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000150:complications / Q000503:physiopathology; D002302:Cardiac Output; D015331:Cohort Studies; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D063177:Pulse Wave Analysis; D017534:Radial Artery; D012720:Severity of Illness Index; D013318:Stroke Volume