Echocardiographic Measurements - References

J Am Coll Cardiol. 1990 Nov;16(5):1168-74.

Left atrial dimensions in growth and development: normal limits for two-dimensional echocardiography.

Pearlman JD, Triulzi MO, King ME, Abascal VM, Newell J, Weyman AE.

Cardiac Unit, Massachusetts General Hospital, Boston 02114.

Reference values for normal left atrial dimensions have been based primarily on blind M-mode measurements, with no reports based on two-dimensional echocardiography to provide a comprehensive analysis of the two-dimensional measurements from infancy to old age. This report analyzes the left atrial dimensions from two-dimensional echocardiographic studies in 268 normal healthy subjects to determine normal limits and relations among linear, area and volume measurements of the left atrium. The group mean values change with body size, fitting well to the exponential growth model (r = 0.78 to 0.92). The variance about the mean (which determines normal limits) is represented effectively by a quadratic function of body surface area (r = 0.84 to 0.99). The variables determined by this modeling simplify evaluation of normal limits for any body size at any desired level of confidence, and the data are useful reference standards for interpretation of two-dimensional echocardiograms.

J Am Coll Cardiol. 1988 Dec;12(6):1432-41.

Limits of normal left ventricular dimensions in growth and development: analysis of dimensions and variance in the two-dimensional echocardiograms of 268 normal healthy subjects.

Pearlman JD, Triulzi MO, King ME, Newell J, Weyman AE.

Cardiac Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114.

The majority of studies generating normal echocardiographic reference values for left ventricular dimensions have been based on blindly performed M-mode measurements, and there are no previous reports based on two-dimensional echocardiography that provide a comprehensive analysis of the two-dimensional measurements from infancy to old age. This report presents the results of analyzing the left ventricular internal dimensions from cross-sectional echocardiographic studies on 268 normal healthy subjects (none were hospitalized for any reason) whose ages ranged from 6 days to 76 years. The mean data are reported as functions of body surface area and, in addition, the variance is modeled as a function of body surface area to provide an accurate and clinically useful determination of normal limits and to model changes in the cardiac dimensions and in their variance representing normal growth and development. The data fit well to the exponential growth model (r values 0.85 to 0.95). Variance about the central values also depended significantly on body size; that relation is represented effectively by a quadratic function of body surface area (r values 0.82 to 0.98). The model parameters allow calculation of normal limits at any desired level of confidence. Areas determined by hand planimetry have significantly greater variance compared with variance of linear dimensions, and also compared with variance of cross-sectional area using ellipses generated from the anteroposterior and mediolateral dimensions. This implies that either biologic variations in the amount of infolding or errors in freehand planimetry constitute a significant source of variance; this may be remedied by filtering out high frequency oscillations of contour. There is no significant difference in midnormal values and confidence limits for corresponding dimensions measured from orthogonal views. Furthermore, the anteroposterior and mediolateral dimensions of the left ventricle superimpose at each body size, consistent with circular cross section for normal subjects throughout growth and development. The data presented should comprise a useful set of reference standards for interpretation of cross-sectional echocardiograms.

Am J Cardiol. 1989 Sep 1;64(8):507-12.

Two-dimensional echocardiographic aortic root dimensions in normal children and adults.

Roman MJ, Devereux RB, Kramer-Fox R, O'Loughlin J.

Department of Medicine, New York Hospital-Cornell Medical Center, New York 10021.

Two-dimensional echocardiography is increasingly used to measure aortic root dimensions, which provide prognostic information in aortic regurgitation and the Marfan syndrome. Aortic root dilatation is currently detected by nomograms based on M-mode echocardiographic data. Aortic root diameters measured by 2-dimensional echocardiography at the anulus, sinuses of Valsalva, supra-aortic ridge and proximal ascending aorta in 135 normal adults and 52 normal children were compared with age, gender, body habitus, blood pressure and stroke volume, and with M-mode findings and normal limits. Two-dimensional measurements at the sinuses of Valsalva were larger than M-mode aortic root values (p less than 0.001), and use of 2-dimensional values with M-mode nomograms falsely diagnosed aortic dilatation in 40% of normal children and 19% of normal adults. Two-dimensional measurements at the sinuses closely correlated with body surface area in children (r = 0.93, p less than 0.0005), moderately in adults younger than 40 years of age (r = 0.71, p less than 0.0005) and weakly in older adults (r = 0.40, p less than 0.0005). In adults, gender influenced aortic root size at all levels (p less than 0.001), but dimensions were similar when indexed for body surface area. Age strongly influenced supraaortic ridge and ascending aortic diameters; blood pressure and stroke volume had no independent effect on aortic size. In conclusion, (1) 2-dimensional echocardiographic aortic root dimensions are influenced by age and body size but not by blood pressure; (2) aortic root dilatation is overdiagnosed when aortic diameter at the sinuses of Valsalva is compared with M-mode nomograms; (3) nomograms comparing aortic diameter with body surface area should be used in children; and (4) although use of nomograms based on body size in adults should maximize sensitivity for aortic dilatation, 98% specificity is attained by use of an upper normal limit of 2.1 cm/m2 for aortic diameter at the sinuses of Valsalva in both men and women.

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