Exercise capacity and stroke volume are preserved late after tetralogy repair, despite severe right ventricular dilatation.

Abstract

To assess if exercise capacity and resting stroke volume are different in tetralogy of Fallot (TOF) repair survivors with indexed RV (right ventricle) end-diastolic volume (RVEDVi) more versus less than 150 ml/m(2), a currently suggested threshold for pulmonary valve replacement (PVR). Cross-sectional study. Single-centre adult congenital heart disease unit. 55 consecutively eligible patients with repaired TOF (age at repair 2.3±1.9 years; age at evaluation 26.2±8.8 years; NYHA Class I or II). Cardiovascular MRI (1.5T) and cardiopulmonary exercise test. Biventricular volumes and function; exercise capacity. 20 patients had RVEDVi below, and 35 had RVEDVi above 150 ml/m(2), at time of referral. In the >150 ml/m(2) group, fractional pulmonary regurgitation was higher (41±8 vs 31±8%, p<0.001). Although RV ejection fraction (EF) was lower (47±7 vs 54±6%, p=0.007), indexed RV stroke volume was higher (87±14 vs 64±10 ml/m(2), p<0.001) in the >150 ml/m(2) group. There were no significant differences in LVEF, indexed LV stroke volume or exercise capacity (% predicted peak work: 90±17 vs 89±11% and; % predicted VO(2) peak: 84±17 vs 87±12%). Exercise capacity and stroke volume are maintained with RVEDVi above compared with below a commonly used cut-off for PVR surgery. Optimal timing for PVR, thus, remains unclear.