title: Low-level exercise echocardiography fails to elicit left ventricular contractile reserve in patients with aortic stenosis, reduced ejection fraction, and low transvalvular gradient.
abstract: BACKGROUND
  Low-level exercise echocardiography is useful to assess left ventricular (LV) contractile reserve after an acute myocardial infarction. Whether low-level exercise can elicit LV contractile reserve in patients with severe aortic stenosis, reduced LV systolic function and low transvalvular gradient are unknown. Accordingly, the value of low-level exercise to elicit contractile reserve was assessed in these patients using dobutamine administration as the gold standard method.
  
  
  RESULTS
  Seventeen patients with severely decreased aortic valve area (0.75 +/- 0.03 cm(2)), reduced LV ejection fraction (35 +/- 2%) and low mean transvalvular gradient (23 +/- 3 mmHg) underwent low-level exercise and dobutamine echocardiography. Ejection fraction increased by 23% (P < 0.001) with dobutamine and decreased by 8% (P = 0.2) with low-level exercise. Left ventricular outflow tract velocity time integral increased from 13 +/- 1 to 16.7 +/- 1 cm (P < 0.001) with dobutamine but did not change with low-level exercise (13 +/- 1 vs. 13.5 +/- 1, P = 0.5).
  
  
  CONCLUSIONS
  Low-level exercise fails to elicit LV contractile reserve in patients with severe aortic stenosis, reduced LV systolic function, and low transvalvular gradient.
authors.affiliation: Cardiology Hospital, Lille, France. ennezat@yahoo.com
authors.forename: Pierre V
authors.initials: PV
authors.lastname: Ennezat
authors.forename: Juliette
authors.initials: J
authors.lastname: Toussaint
authors.forename: Sylvestre
authors.initials: S
authors.lastname: Maréchaux
authors.forename: Thierry
authors.initials: T
authors.lastname: Le Tourneau
authors.forename: Jean Marc
authors.initials: JM
authors.lastname: Aubert
authors.forename: Philippe
authors.initials: P
authors.lastname: Asseman
authors.forename: Thierry H
authors.initials: TH
authors.lastname: LeJemtel
authors.forename: Ghislaine
authors.initials: G
authors.lastname: Deklunder
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000187:drug effects; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002316:Cardiotonic Agents / Q000008:administration & dosage; D004280:Dobutamine / Q000008:administration & dosage; D025401:Echocardiography, Stress; D005260:Female; D006801:Humans; D008297:Male; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine