Left atrium reclassified: Application of the American Society of Echocardiography/European Society of Cardiology cutoffs to unselected outpatients referred to the echocardiography laboratory

Objectives: We sought to determine whether categorization of abnormal left atrial (LA) size based on volumes indexed to body surface area (LAVi) results in reclassification of LA dilatation if the classic antero-posterior diameter (LAd) was measured. The American Society of Echocardiography/ European Society of Cardiology recommended LAVi over linear measurements and recently published cutoffs to qualify LA dilatation. However, many laboratories continue to use the LAd because it appears easier to measure. Methods: Unselected adult outpatients referred to the echocardiography laboratory for any indication in the period March 2005 to January 2006 prospectively underwent standard Doppler echocardiography, including real-time measurement of LAd and LAVi. Results: We enrolled 578 patients (mean age 66 +/- 14 years, 56% women). There was a good positive linear correlation between LAd and LAVi (r = 0.686, P < .0001). When the published cutoffs for LA enlargement were used, 49.0% of patients were classified as having abnormal LA by LAd and 76.3% by LAVi (P < .001). Of the 295 who had normal LA by LAd, 58.6% patients had abnormal LAVi. Conversely, of the 283 with abnormal LAd, almost all patients (94.7%) had abnormal LAVi. The proportion of overall agreement was 67.5% (kappa = 0.357, P < .001). Conclusion: Assessment of LA size by LAVi allows identification of patients with enlarged atria that would have been missed if classified by antero-posterior diameters, especially when cutoffs are applied.