Interpretation of left ventricular dimensions of neonates obtained from echocardiographic examinations during the early neonatal period

Abstract. BACKGROUND: In neonates without physiological pulmonary hypertension, left ventricular end-diastolic dimensions (LVDd) are determined with two-dimensional echocardiography and formulated equations. However, there has not been discussed the meanings of dimensions in early neonatal periods, although the short-axis view of the left ventricle is not round at this age. The objective of this study was to assess LVDd in neonates during early neonatal periods. METHODS: The study group consisted of 460 full-term neonates (230 boys; 230 girls) without congenital heart disease. The iE33 apparatus was employed to examine and measure the LVDds and the longest and shortest dimensions in the short-axis view. RESULTS: A significant difference was observed between the real LVDds and the estimated normal dimensions that were calculated from the formula; LVDd(mm) = 0.352×Ht(cm)+1.86, (P = 0.020). The mean LVDds were estimated to be 97% of the normal LVDds. The real LVDds were influenced by the angle formed by the real LVDds and the longest dimension. CONCLUSIONS: The real LVDds were shorter than normal LVDds. These findings establish normal values for LVDds in the early neonatal period.

*Corresponding Author: 

Dr. Hiroyuki Nagasawa, Department of Neonatology, Gifu Prefectural General Medical Center, 500-8717 Noisshiki 4-6-1, Gifu, Japan. Tel.: +81 58 246 1111; Fax: +81 58 247 3748; E-mail: