title: Does second harmonic imaging improve left ventricular endocardial border identification at higher heart rates during dobutamine stress echocardiography?
abstract: BACKGROUND
  The increased heart rate during dobutamine stress echocardiography (DSE) may impair endocardial border visualization. Second harmonic imaging (SHI) enhances left ventricular (LV) border visualization compared with conventional fundamental imaging (FI) at rest. However, its role during DSE is not well established yet.
  
  
  OBJECTIVE
  Our objective was to compare the additional value of SHI to FI for the LV endocardial border visualization during various stages of DSE.
  
  
  METHODS
  Eighty patients underwent DSE. Imaging was performed with both FI and SHI at rest and at low-and peak-dose dobutamine infusion. Endocardial border visualization was assessed by using a 16-segment/3-point score (0 = well visualized; 1 = poorly visualized; 2 = not visualized).
  
  
  RESULTS
  Heart rate increased from rest (70 +/- 13 bpm) to low-dose dobutamine (77 +/- 17, P <.01) and showed further increase at peak dose (129 +/- 16, P <.001 versus low dose). There was a higher prevalence of segments with an invisible LV endocardial border with FI compared with SHI at rest (9.4% versus 6.2%, P <.0001), at low dose (10.8% versus 6.3%, P <.0001), and at peak dose (15.0% versus 8.2%, P <.0001). There was an increase in the number of segments with an invisible border from rest to peak stress by FI (P =.0001), whereas the difference was less significant for SHI (P =.07).
  
  
  CONCLUSIONS
  Second harmonic imaging improves visualization of the LV endocardial border compared with FI during DSE. The advantage of SHI over FI is more marked at higher heart rates than at rest.
authors.affiliation: Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: F B
authors.initials: FB
authors.lastname: Sozzi
authors.forename: D
authors.initials: D
authors.lastname: Poldermans
authors.forename: E
authors.initials: E
authors.lastname: Boersma
authors.forename: A
authors.initials: A
authors.lastname: Elhendy
authors.forename: J J
authors.initials: JJ
authors.lastname: Bax
authors.forename: A
authors.initials: A
authors.lastname: Borghetti
authors.forename: J R
authors.initials: JR
authors.lastname: Roelandt
mesh_terms: D000368:Aged; D002316:Cardiotonic Agents; D004280:Dobutamine; D004452:Echocardiography / Q000379:methods*; D004699:Endocardium / Q000000981:diagnostic imaging*; D006339:Heart Rate; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine