Assessment of cardiovascular dynamics by pressure-area relations in pediatric patients with congenital heart disease

Objectives: It is particularly useful to separately quantify the ventricula r contractility and loading conditions for a better understanding of the ca rdiovascular dynamics in congenital heart disease, where abnormalities in c hamber and loading properties may coexist. Furthermore, ventricular contrac tility and loading conditions may alter independently or simultaneously wit h disease progression and therapeutic intervention. The objectives of the p resent study were (1) to test whether ventricular pressure-area analysis ca n provide such quantitation among patients with various forms of congenital heart disease, (2) to reveal basal cardiovascular interaction in congenita l heart disease by means of pressure-area analysis, and (3) to test the fea sibility of this method in a simplified and less invasive form to further e nhance its clinical value. Methods: We constructed pressure-area loops during caval occlusion by using transthoracic echocardiographic automated border detection combined with v entricular pressure recordings in 59 pediatric patients with congenital hea rt disease and in 7 normal control subjects. Results: Area measurements obtained by automated border detection were high ly reproducible, and area changes reflected volume changes. The pressure-ar ea data provided load-independent measures of contractility, which were con sistently increased by use of dobutamine (P <.05). End-systolic and arteria l elastance individually quantified simultaneous changes in ventricular con tractility and loading with milrinone infusion and predicted net cardiac pe rformance. The pressure-area analysis better characterized the ventricular contractile states under a variety of loading conditions in congenital hear t disease, whereas predominant load dependence of conventional indices conf ounded them. Furthermore, pressure-area relations were reasonably estimated from a single beat and from aortic pressure data during abdominal compress ion. Conclusions: Pressure-area analysis should provide a useful modality with w hich to assess cardiovascular dynamics in pediatric patients with congenita l heart disease in more detail and should thus help improve the management of patients with this disease.