Normal values for left ventricular volume in infants and young children by the echocardiographic subxiphoid five-sixth area by length (bullet) method.

BACKGROUND: Left ventricular (LV) end-diastolic volume (LVEDV) can be estimated by the formula (5/6) x area x length, or the "bullet" method. The aim of this study was to determine the range of normal LVEDV values in infants and young children (aged 0-3 years) by the subxiphoid bullet method.
METHODS: Echocardiograms from 100 normal subjects aged ≤ 3 years were retrospectively analyzed. Subjects with systemic disease, abnormal body size, cardiovascular disease, or nondiagnostic subxiphoid images were excluded. Measurements of LV short-axis cross-sectional diastolic area at the midventricular level and LV length were made offline from subxiphoid images. LVEDV was indexed to body surface area (BSA) to the powers of 1.0 and 1.38. Relationships between indexing methods, age, and gender were explored.
RESULTS: The median age was 0.98 years (range, 0-2.9 years), the median weight was 9.5 kg (range, 3.1-16.0 kg), and the median BSA was 0.45 m(2) (range, 0.21-0.66 m(2)). The mean LVEDV/BSA(1.38) was 70.4 ± 9.1 mL/m(2.6), with an excellent correlation between LVEDV and BSA(1.38) (r = 0.96, P < .01). There was no residual relationship between LVEDV/BSA(1.38) and BSA (r = 0.06, P = NS) and no significant relationship between LVEDV/BSA(1.38) and age (r = 0.10, P = NS) or LVEDV/BSA(1.38) and gender.
CONCLUSIONS: The normal range for LVEDV by the subxiphoid echocardiographic bullet method is reported for newborns, infants, and young children. LVEDV should be indexed to BSA(1.38), which is consistent with the known relationship between LV size and body size. In children aged ≤ 3 years, these data can be used to calculate Z scores for LVEDV by the subxiphoid bullet technique independent of age or gender.