BACKGROUND: Strain imaging offers an alternative non-invasive method to quantify right ventricular (RV) function. This study aims to utilize strain imaging in the assessment of RV function among repaired Tetralogy of Fallot patients in order to determine clinical RV dysfunction.
METHODOLOGY: This is a prospective cross-sectional study done at the Philippine Heart Center. Cardiac magnetic resonance imaging (CMR) and echocardiographic strain imaging were done on the same day for each study participant. Statistical comparison was performed. Sensitivity and specificity curves (using CMR-derived RV ejection fraction [RVEF] as the reference test) was used to determine optimal cutoff values for global and regional longitudinal systolic strain and strain rate. Intra-observer variability was also determined.
RESULTS: Twenty-two participants were included. There was significant inverse moderate correlation between CMR-derived RVEF and RV free wall (RVFW) mid-segment strain (r=-0.42; p=0.05) and global longitudinal strain (r= 0.62; p=0.002). The determined cut-off for RV dysfunction for RV global longitudinal strain was -20.66%, which showed a sensitivity of 88.83%, specificity of 100%, positive predictive value (PPV) of 100% and negative predictive value (NPV) of 88.83%. RVFW mid-segment strain determined cut-off was -16.25, which showed a sensitivity of 83.33%, specificity of 100%, PPV of 100% and NPV of 83.33%.
CONCLUSION: Strain imaging is an easy, feasible and reproducible parameter in two-dimensional echocardiography that can be a good screening tool, with high sensitivity and specificity for detecting RV dysfunction among patients with repaired Tetralogy of Fallot.