Right Atrial Functional Reserve is Associated With Right Ventricular Diastolic Reserve and Liver Stiffness in Repaired Tetralogy of Fallot

ABSTRACT Aims The importance of right atrial (RA) functional reserve during exercise is recognized in patients with heart failure with preserved ejection fraction. This study aimed to determine RA functional reserve during exercise and to explore its associations with right ventricular (RV) functional reserve and liver stiffness in patients with repaired TOF. Materials and Methods Forty‐seven subjects, including 22 patients, aged 17.9 ± 3.8 years, with repaired TOF and 25 age‐matched controls, were studied. RA and RV systolic and diastolic functional reserve were assessed by speckle tracking and tissue Doppler echocardiography, respectively, at rest and during bicycle exercise. Exercise‐induced changes in RA reservoir strain (∆RA reservoir strain) and tricuspid systolic and diastolic annular velocities were determined. RA functional reserve index (RAFR) is calculated as ∆RA reservoir strain x (1–1/baseline RA reservoir strain). Hepatic shear wave velocity and tissue elasticity were assessed by two‐dimensional shear wave elastography. Results At rest, patients compared with controls had significantly lower RA strain and strain rates (all p  < 0.05). Patients had significantly reduced RAFR index (8.5 ± 4.4 vs. 11.0 ± 4.8, p = 0.044), RV systolic functional reserve (6.6 ± 2.9 vs. 3.7 ± 2.2, p  < 0.001), and RV diastolic functional reserve (8.9 ± 4.7 vs. 5.2 ± 3.3, p = 0.002). Patients had higher hepatic shear wave velocity (1.3 ± 0.2 m/s vs. 1.1 ± 0.2 m/s, p = 0.002) and hepatic E values (5.9 ± 1.5 kPa vs. 4.5 ± 1.0 kPa, p  < 0.001) than controls. Among patients, the hepatic E value correlated significantly with the RAFR index ( r = −0.36, p = 0.03). Multivariate analysis further showed that RV diastolic reserve was the only independent correlate of the RAFR index ( β = −0.33, p = 0.014). Conclusion RA functional reserve during exercise stress is impaired and is associated with RV diastolic reserve and liver stiffness in adolescents and young adults after repair of TOF. Clinical trial registration Not applicable.