title: Moderate-dose dobutamine maximizes left ventricular contractile response during dobutamine stress echocardiography in children.
abstract: BACKGROUND
  Assessment of ventricular contractile reserve by dobutamine stress echocardiography (DSE) may be a powerful tool for detection of subclinical ventricular dysfunction, however, the hemodynamic dose-response relationship during DSE in children has not been established.
  
  
  METHODS
  To characterize changes in hemodynamics and ventricular contractility during DSE in children, 26 participants (age 8.3 +/- 4.8 years; 17 male/9 female) with normal resting left-ventricular function underwent DSE. Participants with abnormal wall motion at rest or during DSE, or rejection were excluded. Left ventricular M-mode echocardiography and carotid pulse tracings were obtained at each stage for calculation of shortening fraction, velocity of circumferential fiber shortening (VCFc), and end-systolic wall stress (WS). Contractility was expressed as the difference between actual and predicted VCFc for measured WS. Dose-response curves for shortening fraction, VCFc, WS, and contractility (the difference between actual and predicted VCFc for measured WS) were obtained.
  
  
  RESULTS
  Stepwise changes in contractility, systolic blood pressure, WS, and left ventricular shortening fraction were observed at doses up to, but not beyond, 20 microg/kg/min. Increases in double product were observed at doses up to 30 microg/kg/min.
  
  
  CONCLUSIONS
  DSE at a dobutamine dose of 20 microg/kg/min is optimal to fully assess contractile reserve in children. Lesser doses may provide insufficient stress, whereas higher doses may incur unnecessary increases in myocardial oxygen consumption and side effects.
authors.affiliation: Noninvasive Cardiac Imaging and Hemodynamic Research Laboratory, Division of Cardiology, Children's Hospital Medical Center, Cincinnati, OH 45229, USA. miche0@chmcc.org
authors.forename: Erik C
authors.initials: EC
authors.lastname: Michelfelder
authors.forename: Sandra A
authors.initials: SA
authors.lastname: Witt
authors.forename: Philip
authors.initials: P
authors.lastname: Khoury
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Kimball
mesh_terms: D000293:Adolescent; D002316:Cardiotonic Agents / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D004280:Dobutamine / Q000008:administration & dosage*; D025401:Echocardiography, Stress; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007223:Infant; D008297:Male; D009200:Myocardial Contraction; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine