title: Comparative usefulness of myocardial velocity gradient in detecting ischemic myocardium by a dobutamine challenge.
abstract: OBJECTIVE
  We tested the hypothesis that ischemic myocardium can be sensitively detected using tissue Doppler-derived myocardial velocity gradient (MVG) by a dobutamine challenge.
  
  
  BACKGROUND
  Although tissue Doppler imaging (TDI) has recently emerged to quantify regional myocardial contraction, increased translational motion during a dobutamine challenge may affect the measurements. MVG is an indicator of regional myocardial contraction independent of the translational motion.
  
  
  METHODS
  We studied 19 patients with (n = 13) and without (n = 6) confirmed single-vessel coronary artery disease. Left ventricular short-axis tissue Doppler images were obtained along with conventional echocardiograms during a submaximal two-step dobutamine challenge (10 and 30 microg/kg body weight per min). Endocardial velocity as well as MVG were derived from TDI using computer analysis in the anteroseptal and posterior segments and were compared with visual interpretation.
  
  
  RESULTS
  MVG demonstrated a significant dose-responsive increase in the nonischemic segments (anteroseptal: 2.6 +/- 0.8/s to 6.0 +/- 1.0/s [mean +/- SD], p < 0.05; posterior: 3.9 +/- 0.7/s to 7.6 +/- 1.8/s, p < 0.05) but remained unchanged in the ischemic segments (anteroseptal: 2.5 +/- 0.8/s to 2.7 +/- 0.7/s, p = NS; posterior: 3.4 +/- 1.0/s to 4.1 +/- 0.9/s, p = NS). Endocardial velocity failed to clearly demonstrate the differing responses between the nonischemic (anteroseptal: -2.3 +/- 1.2 to -2.7 +/- 1.6 cm/s, p = NS; posterior: 3.8 +/- 1.1 to 73 +/- 2.7 cm/s, p < 0.05) and ischemic segments (anteroseptal: -2.1 +/- 0.5 to -2.8 +/- 0.8 cm/s, p = NS; posterior: 4.2 +/- 0.8 to 6.5 +/- 2.6 cm/s, p = NS). Wall motion abnormality was hardly detectable with visual interpretation (wall motion score range 1.00 to 1.33).
  
  
  CONCLUSIONS
  Abnormal segments could be sensitively detected by using MVG in a submaximal dobutamine challenge, even where conventional methods failed to detect the abnormality.
authors.affiliation: Cardiology Division of Medicine, National Cardiovascular Center, Suita, Osaka, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Tsutsui
authors.forename: M
authors.initials: M
authors.lastname: Uematsu
authors.forename: H
authors.initials: H
authors.lastname: Shimizu
authors.forename: M
authors.initials: M
authors.lastname: Yamagishi
authors.forename: N
authors.initials: N
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Matsuda
authors.forename: K
authors.initials: K
authors.lastname: Miyatake
mesh_terms: D000368:Aged; D002316:Cardiotonic Agents; D004280:Dobutamine; D004305:Dose-Response Relationship, Drug; D018618:Echocardiography, Doppler, Color / Q000379:methods; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging*; D015588:Observer Variation; D012680:Sensitivity and Specificity
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine