title: Diagnostic accuracy of electrocardiography and thoracic radiography in the assessment of left atrial size in cats: comparison with transthoracic 2-dimensional echocardiography.
abstract: BACKGROUND
  Left atrial (LA) enlargement (LAE) is a morphologic expression of the severity and chronicity of left ventricular (LV) diastolic dysfunction, volume overload, and increased atrial pressure and has diagnostic, therapeutic, and prognostic importance in cats. The noninvasive gold standard for assessing LA size is 2-dimensional echocardiography (2DE).
  
  
  OBJECTIVE
  ECG and thoracic radiography may be used to predict LAE in cats.
  
  
  METHODS
  Twenty-one healthy control cats and 31 cats with cardiomyopathy were prospectively studied.
  
  
  METHODS
  2DE studies, including determination of the maximum LA dimension (LAD) and area (LAA), were performed prospectively in all cats and compared to the assessment of LA size based on thoracic radiography and indices obtained from a 6-lead ECG. Results obtained from healthy cats were used to generate discrimination limits suggestive of LAE as defined by LAD > 1.57 cm and LAA > 2.75 cm2.
  
  
  RESULTS
  In cats with LAE, P wave duration and PR interval were prolonged and radiographic LA vertebral heart size (LA-VHS) was increased (P < .05). P wave-related indices had low sensitivity (Se; range, 0.12 to 0.60) but high specificity (Sp; range, 0.81 to 1.00) for the prediction of LAE. Radiographic indices had low Se (range, 0.28 to 0.72) and high Sp (range, 0.74 to 0.95) for the prediction of LAE. Correlation analyses identified correlations between LAA and P wave duration (r = 0.47, P = .003) and LAD and LA-VHS (r = 0.70, P < .001).
  
  
  CONCLUSIONS
  ECG and thoracic radiography are reasonably specific but less sensitive predictors of LAE in cats.
authors: Department of Veterinary Clinical Sciences, The Ohio State Universiy, Columbus, OH 43210, USA. schober.4@osu.edu
authors: Karsten E
authors: KE
authors: Schober
authors: Imke
authors: I
authors: Maerz
authors: Eberhard
authors: E
authors: Ludewig
authors: Joshua A
authors: JA
authors: Stern
mesh_terms: D000818:Animals; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000662:veterinary*; D002371:Cat Diseases / Q000000981:diagnostic imaging*; D002415:Cats; D004562:Electrocardiography / Q000662:veterinary*; D005260:Female; D006321:Heart / Q000033:anatomy & histology*; D008297:Male; D013902:Radiography, Thoracic / Q000662:veterinary*