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 < .03), whereas 2C volume displayed the closest correlation (r = 0.20 with ANP and r = 0.28 with BNP, both P < .001) and even slightly exceeded 2C area, 4C volume, and 4C area. 2C volume further displaced LV systolic function, mass index, and heart rate as statistically significant predictors of ANP (P < .001) and BNP (P < .001) on adjusted regression analysis, whereas M-mode diameter was displaced as a significant predictor of ANP and BNP (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.
Klinik und Poliklinik der Inneren Medizin II, Klinikum der Universität Regensburg, Regensburg, Germany. stefan.buchner@klinik.uni-regensburg.de
Stefan
S
Buchner
Michael
M
Muscholl
Kurt
K
Debl
Hans-Werner
HW
Hense
Angela
A
Döring
Jan
J
Stritzke
Heribert
H
Schunkert
Michihisa
M
Jougasaki
John C
JC
Burnett
Günter A J
GA
Riegger
Andreas
A
Luchner
D000368:Aged; D009320:Atrial Natriuretic Factor / Q000097:blood*; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000378:metabolism*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*
D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor