Correlation of left ventricular angiographic casts and biplane left ventricular volumetry in infants and children

To calculate left ventricular (LV) volumes from biplane cineangiography obtained in nonstandard views, regression equations were developed from LV casts of known volume. Volumes were calculated by the area-length method from casts ranging from 1.4 to 48.9 ml obtained from 30 postmortem cases with heart disease. The casts were divided into 2 groups: group I (n = 17) with abnormal and group II (n = 13) with normal right ventricular hemodynamics. Biplane cinegrams were taken in the anterolateral, anterior and long axial oblique, hepatoclavicular and sitting-up projections. The true volume of each cast was determined from its weight and specific gravity. In both groups, excellent correlations were obtained between measured and true volumes (r = 0.92 to 0.99) in all projections, although each projection overestimated the true volume (slope value less than 1). The regression equations obtained from group I were significantly different from those in group II in all views (p less than 0.025 to 0.05), with smaller mean differences and standard errors of the estimate. These data support the concept that right ventricular hemodynamics influence ventricular septal position and, therefore, LV geometry and measured volumes. Appropriate regression equations are required to allow volume calculation from multiple projections.