title: Contrast-enhanced tissue Doppler imaging of the left atrial appendage is a new quantitative measure of spontaneous echocardiographic contrast in atrial fibrillation.
abstract: OBJECTIVE
  Although left atrial appendage spontaneous echo contrast (LAASEC) is a marker of increased thromboembolic risk in atrial fibrillation, it has previously only been evaluated qualitatively. We sought to determine if an intravenous contrast echocardiographic agent combined with tissue Doppler imaging (TDI) of the LAA could accurately quantify LAA-SEC in patients with atrial fibrillation.
  
  
  RESULTS
  We prospectively identified 55 patients with persistent atrial arrhythmias (mean age 63+/-13 years) undergoing a transesophageal echocardiography (TEE), with LAA-SEC prior to direct current cardioversion. In addition to off-line calculation of backscatter index and shear rate, quantification of the velocity in a color TDI region of interest was performed in the LAA cavity following a 0.5-mL intravenous bolus of Optison. LAA-SEC was qualitatively graded by a blindedreader as mild (n = 29) or severe (n = 26), and was compared off-line to TEE-derived quantitative variables. Compared to patients with mild LAA-SEC, those with severe LAA-SEC had significantly decreased LAA emptying velocity, LAA TDI mean velocities and shear rate. Over the whole group, the mean maximal velocity of the LAA using TDI correlated with LAA emptying velocity (r = 0.59; P < 0.0001), shear rate (r = 0.55; P < 0.0001) and LAA area (r = 0.34; P = 0.014). Severe LAA-SEC was found with 72% sensitivity and 82% specificity if TDI mean velocity was <6.13 cm/s. On logistic regression analysis, LAA-TDI was the only predictor of qualitative LAA-SEC grade.
  
  
  CONCLUSIONS
  Contrast-enhanced TDI is an original new tool that provides a quantification of the mean velocity of LAA-SEC that might improve our decision making in patients with atrial fibrillation.
authors.affiliation: CHU Rennes, Rennes, France.
authors.forename: Erwan
authors.initials: E
authors.lastname: Donal
authors.forename: John A
authors.initials: JA
authors.lastname: Sallach
authors.forename: R Daniel
authors.initials: RD
authors.lastname: Murray
authors.forename: Jeanne K
authors.initials: JK
authors.lastname: Drinko
authors.forename: Susan E
authors.initials: SE
authors.lastname: Jasper
authors.forename: James D
authors.initials: JD
authors.lastname: Thomas
authors.forename: Allan L
authors.initials: AL
authors.lastname: Klein
mesh_terms: D000418:Albumins / Q000008:administration & dosage; D020517:Atrial Appendage / Q000000981:diagnostic imaging*; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000008:administration & dosage; D017548:Echocardiography, Transesophageal; D005260:Female; D005466:Fluorocarbons / Q000008:administration & dosage; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012044:Regression Analysis
chemical_list: D000418:Albumins; D003287:Contrast Media; C099458:FS 069; D005466:Fluorocarbons