Assessment of Ventricular Function and Dyssynchrony Before and After Stage 2 Palliation of Hypoplastic Left Heart Syndrome Using Two-Dimensional Speckle Tracking

Abstract

Two-dimensional (2D) speckle tracking (2DST) is a new technique independent of ventricular geometry but not independent of preload and afterload. Using 2DST, this study aimed to investigate differences in right ventricular (RV) function and intraventricular dyssynchrony in patients with hypoplastic left heart syndrome (HLHS) before and after preload-reducing stage 2 palliation. For 31 HLHS patients, this study compared global longitudinal strain (S) and strain rate (SR) as well as regional peak systolic longitudinal S, SR, and velocity (V) in six RV segments on echocardiograms before and after stage 2 surgery. Intraventricular dyssynchrony was assessed by calculating the standard deviation of the intervals from the beginning of systole to peak S, SR, and V. Global S (-16.7 ± 5.0 vs -15.6 ± 5.5%) and global SR (-1.2 ± 0.3 vs -1.2 ± 0.3 s(-1)) did not change after surgery. After surgery, V decreased in the mid lateral segment (2.3 ± 1.3 vs 1.7 ± 0.9 cm/s; p = 0.01) and the basal lateral segment (3.6 ± 1.1 vs 2.8 ± 1.0 cm/s; p = 0.001), whereas S was lower in both of these segments (-19.9% ± 6.0% vs -17.4% ± 6.3%; p = 0.01 and 20.0 ± 5.1 vs 15.8 ± 7.1%; p = 0.002, respectively). Segmental SR and dyssynchrony did not change. Decreased V and S in the RV free wall could be explained by reduced preload of the systemic RV after stage 2 palliation.