Left Atrial Size by Planimetry is Superior to M-mode Diameter: Biochemical Calibration by Atrial and Brain Natriuretic Peptide

Background Left atrial (LA) size is routinely assessed by M-mode on echocardiography. Recently, a superiority of apical measures of LA size has been suggested, but no biochemical calibration has been attempted yet. The aim of the current study was to compare echocardiographic parameters of LA size through biochemical calibration with the natriuretic peptides atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP). Methods A total of 610 middle-aged (50-67 years) subjects from a population-based sample (MONICA Augsburg, Germany) were characterized with respect to LA area and volume from the apical two-chamber (2C) and four-chamber (4C) views in addition to M-mode echocardiography. ANP and BNP concentrations were determined by radioimmunoassay. Results A significant correlation to ANP and BNP was present with all measures on LA size. The univariate correlation was lowest with M-mode diameter ( r = 0.11 with ANP; r = 0.09 with BNP, both P r = 0.20 with ANP and r = 0.28 with BNP, both P P P P = not significant). Conclusions The current population-based echocardiographic study allows new insight into the value of different measures of LA size. The closer association between natriuretic peptide concentrations and parameters derived from planimetry and volumetry suggests a superiority of these parameters LA diameter. LA volumetry should be included in routine echocardiography for optimized assessment of LA size.