title: Impaired left ventricular systolic function reserve limits cardiac output and exercise capacity in HFpEF patients due to systemic hypertension.
abstract: OBJECTIVE
  Heart failure (HF) patients with preserved left ventricular (LV) ejection fraction (EF) (HFpEF) due to systemic hypertension (SHT) are known to have limited exercise tolerance. Despite having normal EF at rest, we hypothesize that these patients have abnormal systolic function reserve limiting their exercise capacity.
  
  
  METHODS
  Seventeen patients with SHT (mean age 68 ± 9 years) but no valve disease and 14 healthy individuals (mean age of 65 ± 10 years) underwent resting and peak exercise echocardiography using conventional, tissue Doppler and speckle tracking techniques. The differences between resting and peak exercise values were also analyzed (Δ). Exercise capacity was determined as the workload divided by body surface area.
  
  
  RESULTS
  Resting values for left atrial (LA) volume/BSA (r=-0.66, p<0.001) and global longitudinal strain rate (GLSR) in early (e) and late (a) diastole (r=0.47 and 0.46, p<0.05 for both) correlated with exercise capacity. LVEF increased during exercise in normals (mean Δ EF=10 ± 8%) but failed to do so in patients (mean Δ EF=0.6 ± 9%, p<0.001 between groups). LV GLSR during systole (s) also failed to increase with exercise in patients, to the same extent as it did in normals (0.2 ± 0.2 vs. 0.6 ± 0.3 1/s, p<0.001). The difference between rest and exercise (Δ) in LV lateral wall systolic velocity from tissue Doppler (s') (0.71, p<0.001), Δ in cardiac output (r=0.60, p<0.001) and Δ GLSRs (r=0.48, p<0.05) all correlated with exercise capacity independent of changes in heart rate.
  
  
  CONCLUSIONS
  HFpEF patients with hypertensive LV disease have significantly limited exercise capacity which is related to left atrial enlargement as well as compromised LV systolic function at the time of the symptoms. The limited myocardial systolic function reserve seems to be underlying important explanation for their limited exercise capacity.
authors.affiliation: Department of Cardiology, Umeå University, Umeå, Sweden; Public Health and Clinical Medicine, Umeå University, Umeå, Sweden.
authors.forename: Michael
authors.initials: M
authors.lastname: Henein
authors.forename: Stellan
authors.initials: S
authors.lastname: Mörner
authors.forename: Krister
authors.initials: K
authors.lastname: Lindmark
authors.forename: Per
authors.initials: P
authors.lastname: Lindqvist
mesh_terms: D000368:Aged; D002302:Cardiac Output / Q000502:physiology*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D054144:Heart Failure, Diastolic / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*