title: Prediction of contractile reserve by cyclic variation of integrated backscatter of the myocardium in patients with chronic left ventricular dysfunction.
abstract: OBJECTIVE
  To clarify whether assessment of the acoustic properties of the myocardium at rest can predict contractile reserve in patients with chronic left ventricular dysfunction.
  
  
  METHODS
  23 patients (mean (SD) age 63 (12) years) with chronic left ventricular dysfunction were studied. The magnitude of cardiac cycle dependent variation of integrated backscatter (CVIB) of the myocardium was measured at rest in the basal and mid segment of the septum and posterior wall of the left ventricle, using a real time two dimensional integrated backscatter imaging system. The results were compared with the percentage wall thickening and the wall motion at rest and during low dose dobutamine infusion. The wall motion was graded as normal, hypokinetic, or akinetic and contractile reserve was considered present when an akinetic or hypokinetic segment improved during dobutamine infusion.
  
  
  RESULTS
  The CVIB at rest correlated with per cent wall thickening at rest and during dobutamine infusion (at rest, r = 0.61, p < 0.0001, during dobutamine, r = 0.76, p < 0.0001). Of the 76 segments examined, 27 showed contractile reserve. The mean CVIB at rest was significantly greater in segments with contractile reserve than in those without (p < 0.0001). CVIB above 3 dB at rest predicted segments with contractile reserve with a sensitivity and specificity of 81% and 60%, respectively (p < 0.0001).
  
  
  CONCLUSIONS
  CVIB reflected not only myocardial contractility but also the functional capacity of the myocardium. It predicted segmental contractile reserve in patients with chronic left ventricular dysfunction.
authors.affiliation: First Department of Internal Medicine, Osaka City University Medical School, 1-4-3 Asahi-machi Abeno-ku, Osaka 545-8585, Japan. tmuro@med.osaka-cu.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Muro
authors.forename: T
authors.initials: T
authors.lastname: Ota
authors.forename: H
authors.initials: H
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Teragaki
authors.forename: K
authors.initials: K
authors.lastname: Takeuchi
authors.forename: J
authors.initials: J
authors.lastname: Yoshikawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002316:Cardiotonic Agents; D002908:Chronic Disease; D004280:Dobutamine; D005260:Female; D006346:Heart Septum / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology*
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine