The impact of measuring methods and normal values for assessment of left atrial size and filling pressures- an echocardiographic study of volume, area and diameter

Abstract

\n \n \n Type of funding sources: None.\n \n \n \n Different normal values for left atrial size are used in different hospitals, most commonly American Society of Echocardiography (ASE) and Normal Reference Range for Echocardiography (NORRE) which is recommended by a national external quality assessor.\n \n \n \n The aim of the study was to compare left atrial volume indexed (LAVI) by Simpson and Area-length (A-L) using the normal values of ASE and NORRE respectively as well as left atrial area and the older anterio-posterior diameter to compare the number of dilated left atria. We also wanted to use the volumes, area and diameter in an algorithm (LAVI, E/e´ and sPAP) for estimation of left ventricular filling pressures.\n \n \n \n 100 men and 100 women examined at the same echo lab in January 2020 were included. Measurements of volume and area were extracted, and the anterio-posterior diameter was measured. The measurements were compared with ASE and NORRE normal values and used in the algorithm to estimate the filling pressure.\n \n \n \n There was an excellent correlation between Simpson and A-L (p <0,001). For A-L there was 50 % increase in dilated left atria compared to NORRE, using Simpson the increase was 38 % (p <0,001). The correlation between Simpson and A-L gave that in LAVI 34 ml/m² according to Simpson corresponded to A-L of 37 ml/m² and 37 ml/m² according to Simpson corresponded to 40 ml/m² according to A-L.\n The number of patients with elevated filling pressure was 7% for NORRES normal values of LAVI (Simpson and A-L), for ASE normal values 10 % (Simpson, ns) and 11% (A-L, p <0,05 compared to NORRE).\n Using LAVI NORRE Simpson as a reference standard the sensitivity for ASE LAVI Simpson and A-L was 100 % and the specificity 75 % and 63 % respectively. The anterio-posterior diameter had the lowest sensitivity (54 %). NORRE LAVI A-L turned out with 99 % specificity and 86 % sensitivity.\n \n \n \n The choice of reference values and measuring method significantly affects the number of dilated left atria but also the assessment of left filling pressures to some degree.\n Abstract Figure.\n