Abstract 14246: Right Atrial Dilation and Conduit Dysfunction is Associated With Significant Pulmonary Insufficiency in Tetralogy of Fallot: Assessment of a New Normative Dataset

Abstract

Background: Right atrial (RA) size and dysfunction predicts adverse clinical outcomes in adult Tetralogy of Fallot (TOF); however limited normative or TOF data are published in children. We aimed to develop and validate 2-dimensional echocardiography normal values for RA size and function in children, by comparison with the RA of children with TOF and to determine the RA size and functional trajectory in TOF after initial repair. Methods: We prospectively imaged 156 healthy children, 13 days to 18 years, and measured RA area at end systole (RAAs), onset of ECG p wave (RAAp) and at end diastole (RAAd), to calculate total RA emptying fraction (EF) (RAAs - RAAd / RAAs), conduit EF (RAAs - RAAp / RAAs), and active EF (RAAp - RAAd /RAAs). Z-scores were developed using BSA indexing. We analysed studies at <1, 3-4 and 6-7 years of age in 22 patients with TOF with sub-analysis according to degree of pulmonic regurgitation: none to mild (G1 n=7) vs. moderate or greater (G2 n=15). Results: RA area indexed to a best-fit power of BSA was homoscedastic. Normal RA conduit EF increased, and RA active EF decreased until a BSA ~1 m 2 before stabilizing, and was best fit by a linear spline function, node at BSA 1 m 2 (Figure 1). TOF RA was dilated early after repair and normalized by 4 years in G1 but not G2. Total RA EF and conduit EF, but not active EF were persistently reduced (Table 1). Conclusion: Using new z-score formulas for indexed RA size and EF, we demonstrate persistent RA dilation and conduit dysfunction in TOF is associated with significant pulmonary regurgitation. Future work will explore the potential utility of RA size and function in prediction of right heart normalization post-pulmonary valve replacement.