Background-Quantitative assessment and validation of left ventricular (LV) volumes and mass in neonates and infantswith complex congenital heart disease (CHD) is important for clinical management but has not been undertaken. We compared matrix-array 3D echocardiography (3D echo) measurements of volumes, mass, and ejection fraction (EF) with those measured by cardiac MRI in young patients with CHD and small LVs because of either young age or LV hypoplasia. Methods and Results-Thirty-five patients aged Ͻ4 years (median, 0.8 years) undergoing MRI were prospectively enrolled. Three-dimensional echo was acquired immediately after MRI, and volume, mass, and EF measurements, using summation of discs methodology, were compared with MRI.

Determination of left ventricular volumes (LVV) is essential for management of infants and small children with complex congenital heart disease (CHD), in particular left heart obstructive lesions. We compared 3-D echo (3DE) LVV in this population to cardiac magnetic resonance (CMR). We prospectively studied children ≤4 y undergoing clinical CMR. Full-volume, subcostal, 3DE data sets were obtained immediately after CMR under similar anesthetic conditions with a 2– 4-MHz matrix-array probe. Endocardial and epicardial borders were manually traced in sequential cross-sectional planes across a minimum of 6 disks. LVVs, mass, and ejection fraction (EF) were subsequently measured on dedicated software using summation of disc methodology. 35 children were studied, including 11 pts with severe LV hypoplasia, median age 7 mo., median weight 7 Kg. Mean vols, mass and EF by 3DE and CMR are shown in the table . LV diastolic vols and mass by 3DE correlated well with good agreement with MRI. 3DE systolic vols correlated well but were higher than MRI (Table , Fig ). EF was thus lower by 3DE. 3DE compares well with CMR for evaluation of LV diastolic volumes and mass in young pediatric patients. This will provide essential information to guide clinical management of pts with CHD, especially those with left heart obstructive disease.