ABSTRACT
BACKGROUND: Previous studies suggest right ventricular (RV) circumferential strain and strain rate from speckle tracking echocardiography (STE) is useful to assess function, despite imaging limitations of RV short axis and tracking algorithms designed for left ventricles. OBJECTIVE: This study compares STE strain and strain rate in patients with single RV to magnetic resonance imaging (MRI) derived strain and strain rate, using proprietary MRI deformation software with published validation in hypoplastic left heart syndrome. Strain and strain rate relationships to MRI derived volumes and function is explored. METHODS: Single RVs patients (n = 25) with STE and MRI performed with an interval up to 35 days, prior to stage 2 palliation (median age 3.9, range 0.9 - 6 months) were compared. STE (GE EchoPAC) and MRI derived longitudinal and circumferential strain and strain rate were analyzed offline. MRI RV end-diastolic (iEDV), end-systolic (iESV) volumes indexed to body surface area and ejection fraction were measured. Bland-Altman plot assessed agreement between the STE and MRI derived deformation measures. Correlations between variables were computed. RESULTS: STE and MRI strain rate had the best agreement between methods, longitudinal strain rate (bias -0.04%; SD 0.26) and circumferential strain rate (bias 0.16 %; SD 0.20) while STE and MRI strain had minimal bias and an acceptable limits of agreement, longitudinal strain (bias 0.4 %; SD 3.2) and circumferential strain (bias -1.7 %; SD 4.4). Greater STE and MRI derived strain and strain rate is associated with smaller iEDV, iESV and greater ejection fraction (see table). MRI circumferential strain and strain rate has a greater correlation with volumes and ejection fraction than MRI longitudinal strain and strain rate. STE circumferential strain rate was best correlated MRI derived volumes and ejection fraction. CONCLUSION: In single RV, STE and MRI derived strain and strain rate showed good agreement, with strain rate having the best equivalency. Furthermore, STE an MRI circumferential strain rate was the most consistently related to MRI derived RV size and function. This study reaffirms the performance of commercially available STE software in single RV and further emphasizes the importance of including circumferential deformation in routine evaluation. (AU)
