Right Ventricular Dysfunction and B-Type Natriuretic Peptide in Asymptomatic Patients After Repair for Tetralogy of Fallot

Early detection of right ventricular (RV) dysfunction is essential in the assessment of patients with repaired tetralogy of Fallot (TOF). This study aimed to assess latent RV dysfunction in asymptomatic patients with TOF and to determine the predictive value of B-type natriuretic peptide (BNP). Pressure-volume loops were recorded for 16 young patients (New York Heart Association class 1 or Ross class 0; median age, 14.2 years) using the conductance catheter technique. All the patients had RV dilation secondary to pulmonary regurgitation after surgical repair of TOF. Indexes of RV function were derived at baseline level and during dobutamine infusion. Contractility was calculated by the slope of the end-systolic pressure-volume relation (ESPVR). An increase in ESPVR during dobutamine infusion was considered to indicate contractile reserve as a marker for latent RV dysfunction. The median ESPVR significantly increased from 0.32 mmHg/ml (0.13-0.72 mmHg/ml) at baseline to 0.57 mmHg/ml (0.24-1.55 mmHg/ml) during dobutamine infusion (p = 0.005). However, for five patients, no relevant increase in contractility was found, indicating impaired RV contractile reserve. There was only a weak inverse correlation between impaired contractile reserve and BNP (r = -0.28). Even asymptomatic patients with only a mildly enlarged right ventricle can have impaired RV function. Early RV dysfunction cannot be predicted accurately with BNP.