Assessment of left ventricular deformation in patients with Ebstein's anomaly by cardiac magnetic resonance tissue tracking

Abstract

Purpose: The aim of this study was to clarify the feasibility of myocardial strain using cardiovascular magnetic resonance (CMR) for the evaluation of left ventricular (LV) deformation in patients with Ebstein's anomaly (EA).

Materials and methods: We recruited 32 patients with EA and 30 controls for CMR examination and measured LV function, dimension and tissue tracking parameters (the global and regional radial, circumferential and longitudinal peak strain), together with the right ventricle (RV) dimension. LV strain parameters were compared among the controls, patients with preserved LV ejection fraction (LVEF; ≥55%), and patients with reduced LVEF (<55%). Pearson's correlation was used to evaluate relationships between tissue tracking parameters with the RVEDD/LVEDD index and LVEF. An ROC analysis was also performed to determine whether the cut-off values for PS could be used to differentiate LV dysfunction between patients with EA and controls. The intraclass correlation coefficient (ICC) was used to assess the inter- and intra-observer variability.

Results: The global strain parameters all decreased significantly in the EA group compared with the control group (all P<0.05). Furthermore, the global radial and circumferential peak strain (PS) were obviously even lower in the reduced LVEF group than the strain measured in preserved LVEF groups (28.64% vs. 37.39%, p<0.05; and -8.20% vs. -17.89%; p<0.05; respectively). The regional strain abnormalities in EA patients were mainly involved in basal and middle segments. The results also demonstrated a significant correlation between the ratio of the RV end-diastolic dimension to the LV end-diastolic dimension (RVEDD/LVEDD index) with the global circumferential PS (r=0.508) and the longitudinal PS (r=0.474), as well as a good correlation between radial PS and LVEF (r=0.465). The ICCs for intra- and inter-observer variability were 0.797-0.904 and 0.701-0.896.

Conclusions: LV strain serves an earlier and more comprehensive measurement of LV dysfunction than LVEF in EA, which could potentially be included as a supplementary diagnostic procedure in the evaluation of EA.

Keywords: Cardiac magnetic resonance; Ebstein’s anomaly; Left ventricular deformation; Tissue tracking.