Progress of right ventricular dilatation in adults with repaired tetralogy of Fallot and free pulmonary regurgitation

BACKGROUND: The time course of progressive dilatation of the right ventricle (RV) in adults with pulmonary regurgitation (PR) late after repair of tetralogy of Fallot (TOF) is poorly characterized. METHODS: We analysed cardiac MRI data (1.5 T) from 14 adult repaired TOF patients (26 ± 11 years of age) with dilated RVs and known significant PR, on 2 separate visits with a between MRI period of 2.1 ± 1.0 years. RESULTS: Indexed RV end diastolic volume (RVEDVi) increased over 2 years (142 ± 19 to 151 ± 20 mL/m(2), p = 0.005; change = 8.4 ± 9.3 mL/m(2), range = − 6 to 26 mL/m(2); annual mL/m(2) increase = 4.3 ± 4.6; annual percentage increase = 3.1 ± 3.3%), whilst RV ejection fraction decreased (53 ± 8 to 49 ± 7 %, p = 0.039). RV muscular corpus (RVMC) EDVi significantly increased (130 ± 19 to 138 ± 20 mL/m(2), p = 0.014), whereas RV outflow tract (RVOT) EDVi did not (12 ± 7 vs 13 ± 6 mL/m(2), p = 0.390). No other RV or LV measures significantly changed during the inter-MRI period. The change in RVEDVi correlated significantly with LV end diastolic volume (r = − 0.582, p = 0.029), RVEDVi:LVEDVi (r = 0.6, p = 0.023) and RVMC EDVi (r = 0.9, p < 0.001) but not RVOT EDVi (r = 0.225, p = 0.459). CONCLUSIONS: Adult repaired TOF patients with free PR experienced a mean 3.1%, or 4.3 mL/m(2), annual increase in RVEDVi, unrelated to the initial RVEDVi or PR fraction. The increase in RVEDVi was due to RVMC rather than RVOT dilatation. This provides a guide to the frequency of MR surveillance and insights into the natural history of progressive RV dilatation in this setting.