Đo đường kính LA duy nhất vẫn còn được ghi lại trong thực tế lâm sàng thường xuyên sử dụng 2D, thường là trong một cái nhìn dài trục parasternal. Bình thường là | 9 ATRIA A single LA diameter measurement is still recorded in routine clinical practice using 2D usually in a parasternal long-axis view. Normal is cm. LA geometry varies and is not accurately represented by a linear dimension. LA size needs to be assessed more accurately if there is - atrial dilatation noted on the initial study - hypertension as a sign of increased filling pressure - atrial fibrillation likely success of cardioversion thromboembolic risk - mitral valve disease thromboembolic risk indirect marker of severity . A simple clinical method is planimetry of the area in a 4-chamber view modified if necessary to optimise atrial size Table and frozen at maximum size just before mitral valve opening. For research studies biplane Simpson s or area-length rule using 4-chamber and 2-chamber views should be indexed to BSA. Table LA dilatation1 2 Mild Moderate Severe LA area cm2 20-29 30-40 40 LA volume BSA ml m2 29-31 32-39 40 interpret within the whole echocardiographic and clinical context Atrial dilatation can give a clue to the diagnosis Tables and . A guide threshold for RA dilatation is a transverse diameter 5 cm in the 4-chamber view. 88 Echocardiography A Practical Guide for Reporting Table Causes of severe biatrial enlargement Apical hypertrophic cardiomyopathy Restrictive cardiomyopathy Rheumatic disease affecting mitral and tricuspid valves Table Causes of right atrial dilatation Tricuspid stenosis or regurgitation Pulmonary hypertension ASD RV myopathy REFERENCES 1. Lang RM Bierig M Devereux RB et al. Recommendations for chamber quantification. Eur J Echocardiogr 2006 7 79-108. 2. Abhayaratna WP Seward JB Appleton CP et al. Left atrial size physiologic determinants and clinical applications. J Am Coll Cardiol 2006 47 .
