title: Quantitative evaluation of left atrial volume and function by one-dimensional, two-dimensional, and three-dimensional echocardiography in a population of normal dogs.
abstract: OBJECTIVE
  The primary goal of this study was to compare left atrial (LA) volume and functional indices in a population of normal dogs using transthoracic one-dimensional M-mode, two-dimensional (2D), and three-dimensional (3D) echocardiography.
  
  
  METHODS
  Forty clinically normal dogs of various breeds were stratified into four groups based on weight.
  
  
  METHODS
  Left atrial volume (LAV) was estimated by converting single linear measurements derived from M-mode and 2D images into volumes via the cube and sphere formulas. 2D echocardiography was employed to estimate LAV using linear measures and rectangular and ellipsoid formulas, as well as area-length and the monoplane method of disks. LAV was estimated using the biplane area-length method on 4- and 2-chamber 2D images. LAV was directly measured using 3D volume data obtained over four consecutive cardiac cycles. LAV estimates were compared amongst methods, correlated to body size, and evaluated for reproducibility. Functional indices derived from these various echocardiographic methods were compared to identify any systematic differences based on imaging modality. LA functional indices included LA ejection fraction (LAEF), total LA emptying volume, passive LA emptying volume/fraction, active LA emptying volume/fraction, and LA expansion index.
  
  
  RESULTS
  The M-mode derived estimates of LAV were significantly smaller than all 2D- and 3D-derived LAV (p<0.0001). The left-sided 3D LAV had the highest correlation with body weight (r2= 0.8806) for all phases of the LA cycle with acceptable interobserver variability (CV 11%).
  
  
  CONCLUSIONS
  3D echocardiography is a feasible, non-invasive method to measure LAV in a population of normal dogs.
authors.affiliation: Oregon State University, College of Veterinary Medicine, 105 Magruder Hall, 700 SW 30th Street, Corvallis, Oregon 97331, USA. Electronic address: nicole.leblanc@oregonstate.edu.
authors.forename: N
authors.initials: N
authors.lastname: LeBlanc
authors.affiliation: Oregon State University, College of Veterinary Medicine, 105 Magruder Hall, 700 SW 30th Street, Corvallis, Oregon 97331, USA.
authors.forename: K
authors.initials: K
authors.lastname: Scollan
authors.affiliation: Oregon State University, College of Veterinary Medicine, 105 Magruder Hall, 700 SW 30th Street, Corvallis, Oregon 97331, USA.
authors.forename: D
authors.initials: D
authors.lastname: Sisson
mesh_terms: D000818:Animals; D016279:Atrial Function, Left; D002306:Cardiac Volume; D004285:Dogs / Q000033:anatomy & histology*; D004452:Echocardiography / Q000662:veterinary*; D019560:Echocardiography, Three-Dimensional / Q000662:veterinary*; D005260:Female; D006325:Heart Atria / Q000033:anatomy & histology*; D008297:Male; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results
keywords: Cardiac volumes; Echocardiogram; Left atrium; M-mode