title: Abnormal haemodynamic response to exercise in heart failure with preserved ejection fraction.
abstract: OBJECTIVE
  Peak oxygen uptake (VO(2)) is diminished in patients with heart failure with preserved ejection fraction (HFpEF) suggesting impaired cardiac reserve. To test this hypothesis, we assessed the haemodynamic response to exercise in HFpEF patients.
  
  
  RESULTS
  Eleven HFpEF patients (73 ± 7 years, 7 females/4 males) and 13 healthy controls (70 ± 4 years, 6 females/7 males) were studied during submaximal and maximal exercise. The cardiac output (Q(c), acetylene rebreathing) response to exercise was determined from linear regression of Q(c) and VO(2) (Douglas bags) at rest, ∼30% and ∼60% of peak VO(2), and maximal exercise. Peak VO(2) was lower in HFpEF patients than in controls (13.7 ± 3.4 vs. 21.6 ± 3.6 mL/kg/min; P < 0.001), while indices of cardiac reserve were not statistically different: peak cardiac power output [CPO = Q(c) × mean arterial pressure (MAP); HFpEF 1790 ± 509 vs. controls 2119 ± 581 L/mmHg/min; P = 0.20]; peak stroke work [SW = stroke volume (SV) × MAP; HFpEF 13 429 ± 2269 vs. controls 13 200 ± 3610 mL/mmHg; P = 0.80]. The ΔQ(c)/ΔVO(2) slope was abnormally elevated in HFpEF patients vs. controls (11.2 ±3.6 vs. 8.3 ± 1.5; P = 0.015).
  
  
  CONCLUSIONS
  Contrary to our hypothesis, cardiac reserve is not significantly impaired in well-compensated outpatients with HFpEF. The abnormal haemodynamic response to exercise (decreased peak VO(2), increased ΔQ(c)/ΔVO(2) slope) is similar to that observed in patients with mitochondrial myopathies, suggesting an element of impaired skeletal muscle oxidative metabolism. This impairment may limit functional capacity by two mechanisms: (i) premature skeletal muscle fatigue and (ii) metabolic signals to increase the cardiac output response to exercise which may be poorly tolerated by a left ventricle with impaired diastolic function.
authors: The Institute for Exercise and Environmental Medicine, 7232 Greenville Avenue, Dallas, TX 75231, USA.
authors: Paul S
authors: PS
authors: Bhella
authors: Anand
authors: A
authors: Prasad
authors: Katja
authors: K
authors: Heinicke
authors: Jeff L
authors: JL
authors: Hastings
authors: Armin
authors: A
authors: Arbab-Zadeh
authors: Beverley
authors: B
authors: Adams-Huet
authors: Eric L
authors: EL
authors: Pacini
authors: Shigeki
authors: S
authors: Shibata
authors: M Dean
authors: MD
authors: Palmer
authors: Bradley R
authors: BR
authors: Newcomer
authors: Benjamin D
authors: BD
authors: Levine
mesh_terms: D000368:Aged; D018450:Disease Progression; D004452:Echocardiography; D004562:Electrocardiography; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left