Exercise Radionuclide Right Ventriculography in Children

Supine exercise equilibrium radionuclide right ventriculography was performed in 13 children (8–18 years) with hypercholesterolemia. Phase analysis was used to construct right ventricular regions of interest, and a peri-right ventricular region was used for background correction. Right ventricular ejection fraction at rest and exercise was 50.5±9.2% and 61.5±8.1%, respectively, with a mean increase of 11.0±7.5 percentage units (range 1–27 percentage units). During exercise, end-diastolic volume remained unchanged while end-systolic volume decreased by 19.4%, producing a 21.7% increase in stroke volume. Stroke volume ratios (left ventricular stroke volume counts/right ventricular stroke volume counts) approach unity (1.00±0.27). However, interobserver and intraobserver correlations are just fair, implying only a modest degree of accuracy and reliability of the procedure. This imprecision needs to be considered when evaluating the results of nuclear equilibrium right ventriculography.