title: Non-contrast second harmonic imaging improves interobserver agreement and accuracy of dobutamine stress echocardiography in patients with impaired image quality.
abstract: OBJECTIVE
  To examine the influence of second harmonic imaging during dobutamine echocardiography on regional endocardial visibility, interobserver agreement in the interpretation of wall motion abnormalities, and diagnostic accuracy in patients with reduced image quality.
  
  
  METHODS
  Blinded comparison.
  
  
  METHODS
  Tertiary care centre.
  
  
  METHODS
  103 consecutive patients with suspected coronary artery disease and impaired transthoracic image quality (>/= 2 segments with poor endocardial delineation).
  
  
  METHODS
  Fundamental and second harmonic imaging were performed at each stage of a dobutamine stress echocardiography. Coronary angiography was undertaken within three weeks of dobutamine echocardiography in 75 patients.
  
  
  METHODS
  Evaluation of regional endocardial visibility (scoring from 0 = poor to 2 = good) and of segmental wall motion abnormalities for both modalities separately. A second blinded examiner analysed 70 studies to determine interobserver agreement.
  
  
  RESULTS
  Mean (SD) visibility score for all segments was 1.2 (0.4) using fundamental imaging and 1.7 (0.2) using second harmonic imaging at rest (p < 0.001), and 1.1 (0.4) v 1.6 (0.3), respectively, at peak dobutamine dose (p < 0.001). The average number of segments with poor endocardial visibility was lower for second harmonic than for fundamental imaging (0.6 (1.1) v 3.8 (2.6) at rest, p < 0.001; 0.9 (1.3) v 4.3 (2.9) at peak dose, p < 0.001). Improvement was most pronounced in all lateral and anterior segments. The kappa value for identical study interpretation increased from 0. 40 to 0.69 (p < 0.05). Sensitivity for the diagnosis of coronary artery disease was 64% using fundamental imaging versus 92% using harmonic imaging (p < 0.001), while specificity remained unchanged at 75% for both imaging modalities.
  
  
  CONCLUSIONS
  Second harmonic imaging enhances endocardial visibility during dobutamine echocardiography. Consequently, interobserver agreement on stress echocardiography interpretation and diagnostic accuracy are significantly improved compared to fundamental imaging. Thus, in difficult to image patients, dobutamine echocardiography should be performed using second harmonic imaging.
authors.affiliation: Medical Clinic I, University Hospital, Pauwelsstrasser 30, D 52057 Aachen, Germany. afra@pcserver.mk1.rwth-aachen.de
authors.forename: A
authors.initials: A
authors.lastname: Franke
authors.forename: R
authors.initials: R
authors.lastname: Hoffmann
authors.forename: H P
authors.initials: HP
authors.lastname: Kühl
authors.forename: W
authors.initials: W
authors.lastname: Lepper
authors.forename: O A
authors.initials: OA
authors.lastname: Breithardt
authors.forename: M
authors.initials: M
authors.lastname: Schormann
authors.forename: P
authors.initials: P
authors.lastname: Hanrath
mesh_terms: D002316:Cardiotonic Agents; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D003954:Diagnostic Services / Q000592:standards*; D004280:Dobutamine; D004452:Echocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012680:Sensitivity and Specificity
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine