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

Patients with repaired TOF had significantly lower RA strain and strain rates at rest compared with controls.

• 22 patients with repaired TOF (aged 17.9 ± 3.8 years) were compared with 25 age-matched controls.
• All RA strain and strain rate comparisons at rest were statistically significant (all p < 0.05).
• RA and RV function were assessed using speckle tracking and tissue Doppler echocardiography.

Patients with repaired TOF had significantly reduced RA functional reserve index (RAFR) compared with controls.

• RAFR index was 8.5 ± 4.4 in patients versus 11.0 ± 4.8 in controls (p = 0.044).
• RAFR index was calculated as Δ RA reservoir strain × (1 − 1/baseline RA reservoir strain).
• Exercise-induced changes in RA reservoir strain (Δ RA reservoir strain) were assessed during bicycle exercise.

Patients with repaired TOF had significantly reduced RV systolic and diastolic functional reserve compared with controls.

• RV systolic functional reserve was 3.7 ± 2.2 in patients versus 6.6 ± 2.9 in controls (p < 0.001).
• RV diastolic functional reserve was 5.2 ± 3.3 in patients versus 8.9 ± 4.7 in controls (p = 0.002).
• RV functional reserve was assessed by tricuspid systolic and diastolic annular velocities at rest and during bicycle exercise.

Patients with repaired TOF had higher liver stiffness than controls as measured by two-dimensional shear wave elastography.

• Hepatic shear wave velocity was 1.3 ± 0.2 m/s in patients versus 1.1 ± 0.2 m/s in controls (p = 0.002).
• Hepatic E values were 5.9 ± 1.5 kPa in patients versus 4.5 ± 1.0 kPa in controls (p < 0.001).
• Liver stiffness was assessed by two-dimensional shear wave elastography measuring hepatic shear wave velocity and tissue elasticity.

Among patients with repaired TOF, hepatic E value correlated significantly with the RAFR index.

• The correlation between hepatic E value and RAFR index was r = −0.36 (p = 0.03).
• This association suggests a link between liver stiffness and impaired RA functional reserve during exercise.

RV diastolic reserve was the only independent correlate of the RAFR index in multivariate analysis among patients.

• Multivariate analysis showed RV diastolic reserve as the sole independent correlate of RAFR index (β = −0.33, p = 0.014).
• This finding indicates that impaired RV diastolic reserve is independently associated with reduced RA functional reserve during exercise in repaired TOF patients.