title: Left atrial to aortic root indices using two-dimensional and M-mode echocardiography in cavalier King Charles spaniels with and without left atrial enlargement.
abstract: Two-dimensional (2-D) echocardiographic measurement of the left atrium (LA) has the potential to be more accurate than the standard M-mode method, because the LA body can be measured. We evaluated a 2-D method for measuring LA and aorta (AO) in a right parasternal short-axis view and compared it to the M-mode method. An index for LA size (LA/AO) was calculated in 166 cavalier King Charles spaniels, 56 normal and 110 dogs with mitral regurgitation (MR) of varying degrees secondary to chronic valvular disease. In normal dogs, the AO-2-D and LA/AO-2-D did not correlate to body weight (BW) or BW2; whereas, all M-mode values and the LA-2-D were significantly (p < .05) related to both BW parameters. In normal dogs, there was no difference between M-mode and 2-D indices. For all dogs (normal and dogs with MR) there was an 11% bias between the M-mode and 2-D index with the LA/AO-2-D being higher than the LA/AO-M. The association between the mean and the difference of the indices demonstrated a quadratic relationship. Dogs with a mean LA/AO of 2.0-2.5 showed the largest difference between the two indices. Small values for the 2-D coefficients of variation for respiration and stage of diastole were found; 3.4 and 3.1%, respectively. The 2-D index is more sensitive to LA enlargement than the M-mode index.
authors.affiliation: Department of Clinical Radiology, Swedish University of Agricultural Sciences, Box 7029, SE-750 07 Uppsala, Sweden. Kerstin.Hansson@klra.slu.se
authors.forename: Kerstin
authors.initials: K
authors.lastname: Hansson
authors.forename: Jens
authors.initials: J
authors.lastname: Häggström
authors.forename: Clarence
authors.initials: C
authors.lastname: Kvart
authors.forename: Peter
authors.initials: P
authors.lastname: Lord
mesh_terms: D000818:Animals; D001011:Aorta / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D001947:Breeding; D016022:Case-Control Studies; D004283:Dog Diseases / Q000000981:diagnostic imaging*; D004285:Dogs / Q000033:anatomy & histology*; D004452:Echocardiography / Q000592:standards / Q000662:veterinary*; D005260:Female; D006325:Heart Atria / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008297:Male; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000662:veterinary*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity