Aims: Velocity vector imaging (VVI) is an echocardiographic technique based on speckle tracking, which has been validated for the left ventricle (LV). It has not been validated to assess the systemic right ventricle (RV) in patients with hypoplastic left heart syndrome (HLHS). The aim of this study was to evaluate whether VVI measurements reliably reflect RV systolic function in patients with HLHS when compared with RV ejection fraction (EF) calculated using magnetic resonance imaging (MRI).
Methods and results: In this prospective study, 49 children with HLHS underwent transthoracic echocardiography and cardiac MRI under the same general anaesthetic as a part of routine assessment between the different stages of palliative surgery. Global RV fractional area change (FAC-VVI), strain (S), strain rate (SR), and peak systolic velocity (V) were analysed from the apical four-chamber view using the VVI technique. MRI-derived EF was calculated from a short-axis cine stack of images. Intra- and interobserver reproducibility was excellent for all VVI parameters (intraclass correlation coefficient >0.9). All VVI-derived parameters, except myocardial velocity, correlated with MRI-derived EF (FAC-VVI: R = 0.7, P < 0.001; S: R = -0.5, P < 0.001; SR: R = 0.5, P = 0.001, and V: R = 0.1, P = 0.4).
Conclusions: All VVI-derived parameters, except V, correlate with MRI-derived EF, with FAC being the best predictor of it. Reproducibility of all VVI parameters is excellent. VVI provides a useful tool for the follow-up of RV function during the staged treatment protocol for HLHS.
Keywords: Hypoplastic left heart syndrome; Magnetic resonance imaging; Myocardial function; Right ventricle; Velocity vector imaging.
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