Detection of Early Signs of Right Ventricular Systolic Impairment in Unoperated Ebstein's Anomaly by Cardiac Magnetic Resonance Feature Tracking

Background: Cardiovascular magnetic resonance feature tracking (CMR-FT) allows a quantitative assessment of myocardial contraction with potential for diagnostic and prognostic ability in a wide spectrum of diseases. Aim of our study was to describe the complex myocardial deformation pattern of the functional right ventricle (RV) in patients with Ebstein’s anomaly (EA) through CMR-FT. Methods: 50 surgery-free EA patients and 25 healthy subjects were included in this retrospective study. CMR-FT data were obtained by contouring the RV borders on cine images, and RV global longitudinal (GLS), circumferential (GCS) and radial (GRS) strain were calculated. Apical displacement of the tricuspid valve (TV) was measured on a 4-chamber cine image from the right atrio-ventricular junction to the functional annulus of the TV. Result: GRS and GCS were significantly lower in EA compared to controls ( p <0.0001 and p = 0.0008, respectively), but not GLS ( p = 0.21). In a subgroup analysis, GRS was significantly compromised in patients with a severely displaced TV compared to milder forms ( p = 0.03) and to controls ( p < 0.0001). RV ejection fraction (RVEF) was lower in EA than in controls ( p < 0.0001). When RVEF was preserved, twelve (48%) vs. six (24%) controls had reduced both GRS and GCS. Conclusion: The functional RV in EA is characterized by a reduction of myocardial contraction prevalent in the short-axis direction, with no significant impairment of longitudinal function. CMR-FT may detect early signs of RV systolic dysfunction in EA, when RVEF is still preserved.