title: Strain-rate imaging during dobutamine stress echocardiography provides objective evidence of inducible ischemia.
abstract: BACKGROUND
  Interpretation of dobutamine stress echocardiography (DSE) is subjective and strongly dependent on the skills of the reader. Strain-rate imaging (SRI) by tissue Doppler may objectively analyze regional myocardial function. This study investigated SRI markers of stress-induced ischemia and analyzed their applicability in a clinical setting.
  
  
  RESULTS
  DSE was performed in 44 patients with known or suspected coronary artery disease. Simultaneous perfusion scintigraphy served as a "gold standard" to define regional ischemia. All patients underwent coronary angiography. Segmental strain and strain rate were analyzed at all stress levels by measuring amplitude and timing of deformation and visual curved M-mode analysis. Results were compared with conventional stress echo reading. In nonischemic segments, peak systolic strain rate increased significantly with dobutamine stress (-1.6+/-0.6 s-1 versus -3.4+/-1.4 s-1, P<0.01), whereas strain during ejection time changed only minimally (-17+/-6% versus -16+/-9%, P<0.05). During DSE, 47 myocardial segments in 19 patients developed scintigraphy-proven ischemia. Strain-rate increase (-1.6+/-0.8 s-1 versus -2.0+/-1.1 s-1, P<0.05) and strain (-16+/-7% versus -10+/-8%, P<0.05) were significantly reduced (both P<0.01 compared with nonischemic). Postsystolic shortening (PSS) was found in all ischemic segments. The ratio of PSS to maximal segmental deformation was the best quantitative parameter to identify stress-induced ischemia. Compared with conventional readings, SRI curved M-mode assessment improved sensitivity/specificity from 81%/82% to 86%/90%.
  
  
  CONCLUSIONS
  During DSE, SRI quantitatively and qualitatively differentiates ischemic and nonischemic regional myocardial response to dobutamine stress. The ratio of PSS to maximal strain may be used as an objective marker of ischemia during DSE.
authors.affiliation: Medizinische Klinik II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Ulmenweg 18, 91054 Erlangen, Germany. jens.uwe.voigt@gmx.net
authors.forename: Jens-Uwe
authors.initials: JU
authors.lastname: Voigt
authors.forename: Bert
authors.initials: B
authors.lastname: Exner
authors.forename: Kristin
authors.initials: K
authors.lastname: Schmiedehausen
authors.forename: Cord
authors.initials: C
authors.lastname: Huchzermeyer
authors.forename: Udo
authors.initials: U
authors.lastname: Reulbach
authors.forename: Uwe
authors.initials: U
authors.lastname: Nixdorff
authors.forename: Günther
authors.initials: G
authors.lastname: Platsch
authors.forename: Torsten
authors.initials: T
authors.lastname: Kuwert
authors.forename: Werner G
authors.initials: WG
authors.lastname: Daniel
authors.forename: Frank A
authors.initials: FA
authors.lastname: Flachskampf
mesh_terms: D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000000981:diagnostic imaging*; D015150:Echocardiography, Doppler; D025401:Echocardiography, Stress; D006801:Humans; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000209:etiology; D012372:ROC Curve; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D013997:Time Factors