Normal values of echocardiography are measured by the M-mode method. However, there is an error in measurements when M-mode beam is not vertical against the left ventricular long axis. The variance of angles between M-mode beam direction recommended by the American Society of Echocardiography (ASE) and vertical line against left ventricular long axis which was located in a two-dimensional parasternal long axis echogram at end-diastole was studied in thirty four normal adult subjects. Two-dimensional echocardiographic measurements were performed to assess the normal values in sixty seven normal adult subjects. The parameters of measurements at end-diastole numbered five as follows: O outside dimension of left ventricle (ODLV), (1) left ventricular dimension (LVD), (3) interventricular septal wall thickness (IVST), (4) posterior left ventricular wall thickness (PWT), (5) aortic root dimension (AoD). The correlation between these five twodimensional echocardiographic parameters and the subjects' body constitution (body height, body weight, BSA, square root of BSA, cube root of BSA) was studied.
The conclusions of this study are: (1) There is a wide variance in the angles between M-mode beam direction and vertical line against left ventricular long axis. In this result, it is suggested that ODLV, LVD, IVST, and PWT are randomly overestimated by the M-mode method. (2) Two-dimensional echocardiographic normal ranges of ODLV, LVD, IVST, PWT, AoD at end-diastole are 55-70 mm, 34-50 mm, 7-13 mm, 7-13 mm, 24-36 mm (-2SD-+2SD) respectively. (3) Correlations between three parameters of body constitution (body height, body weight, BSA) and five echocardiographic parameters were as follows. In ODLV, significant correlation was found against all three parameters of body constitution. The highest parameter was body weight (r=0.47 p<0.001). In LVD, significant and higher correlation was found in body weight (r=0.32 p<0.01) than in BSA (r=0.30 p<0.01). In IVST and PWT, no significant correlation against body constitution was found. In AoD, significant correlation was found against all three parameters of body constitution. The highest parameter was body height (r=0.56 p<0.001). As for ODLV, LVD and AoD, the correlations between these parameters and square root of BSA as well as cube root of BSA were significant. However, these correlations were not higher than direct BSA. It is estimated that ODLV and LVD corrected for body weight and AoD corrected for body height are not only clinically easier but also better than corrected for BSA.
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