Echocardiography for assessment of regional and global right ventricular systolic function in adults with repaired tetralogy of Fallot

Background: The right ventricular (RV) systolic function is important for decision making in adults with repaired tetralogy of Fallot (rTOF). Our aim was to assess regional RV systolic function and its impact on global RV systolic function by echocardiography.

Methods: In 101 adults with rTOF, regional RV systolic function on echocardiography was compared to 50 individuals with structurally normal hearts. In patients with rTOF, the impact of echocardiographic measures of regional RV systolic function on global RV-ejection fraction as measured by cardiac magnetic resonance imaging (CMR-RVEF) was determined.

Results: Compared to normals, patients with rTOF had impaired systolic function of the RV outflow tract. Patients with rTOF and normal CMR-RVEF compensate this loss of RV outflow tract function with increased contractions of the RV-body, measured as fractional area change on short axis (30±12% versus 19±7%, p<0.0001) and on 4-chamber views (42±7% versus 38±8%, p=0.06). In contrast, patients with rTOF and abnormal global CMR-RVEF showed significantly lower systolic function of the RV-body compared to normal controls (fractional area change on 4-chamber view: 31±6% versus 38±8%, p<0.0001). A simple regression model, incorporating fractional shortening of RV outflow tract and fractional area change on 4-chamber view allows accurate echocardiographic estimation of the CMR-derived RVEF.

Conclusions: Patients with repaired tetralogy of Fallot have markedly different regional systolic RV-function compared to normals, even when the global RV systolic function is preserved. The systolic function of the RV outflow tract and of the RV body are both important determinants of global systolic RV function in these patients. Their prognostic significance needs to be determined.