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/m2, p = 0.005; change = 8.4 ± 9.3 mL/m2, range = - 6 to 26 mL/m2; annual mL/m2 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/m2, p = 0.014), whereas RV outflow tract (RVOT) EDVi did not (12 ± 7 vs 13 ± 6 mL/m2, 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/m2, 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.