Calculation of pediatric left ventricular mass: validation and reference values using real-time three-dimensional echocardiography.

BACKGROUND: Reference values for left ventricular mass (LVM) are important echocardiographic tools for the follow-up of pediatric patients with cardiac disease. Cardiac magnetic resonance (CMR) imaging is currently regarded as the gold standard. The aims of this study were to validate LVM calculated using real-time three-dimensional echocardiography (RT3DE) and to establish pediatric reference values.

METHODS: For validation, 40 subjects (20 patients) consecutively underwent CMR (3-T TX Achieva, 25 cardiac phases/slice) and RT3DE (iE33 or Vivid E9, four subvolumes) in a single-center approach. The quantification of CMR data by the disk summation method as standard (mean LVM, 84.2 ± 53 g; range, 17.7-231.7 g) was compared with RT3DE. In a multicenter prospective design, 434 healthy children were investigated using standard software (LV-Analysis version 3.1).

RESULTS: In comparison with CMR, RT3DE provided a slight overestimation of LVM of only 2.5 ± 11.3% (r = 0.990, intraclass correlation coefficient = 0.995), and there was low intraobserver (mean, 0.9 ± 7.1%; scatter, 13.2% to -15.0%; r = 0.996; intraclass correlation coefficient = 0.998) and interobserver (mean, 1.5 ± 9.3%; scatter, 17.2% to -20.1%; r = 0.993; intraclass correlation coefficient = 0.996) variability. Feasibility of the multicenter approach was 76%, resulting in 332 healthy children (median age, 10.0 years; range, 0-18 years; group I range, 0-6 years; group II range, 7-18 years) with data sets providing adequate image quality. LVM was correlated with sex (group II), age (r = 0.901), height (r = 0.881), weight (r = 0.876), and body surface area (r = 0.898). Unisex percentiles for 0 to 6 years of age and separated according to gender from 7 to 18 years of age were established. Mean calculation time for RT3DE was <3 min.

CONCLUSIONS: In children, LVM calculation presuming excellent real-time three-dimensional echocardiographic data sets is accurate, quick, and reproducible. The percentiles provided are based on a large sample size and may be useful for clinical practice.