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

Abstract

<h3>Objectives</h3> 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/m², a currently suggested threshold for pulmonary valve replacement (PVR). <h3>Design</h3> Cross-sectional study. <h3>Setting</h3> Single-centre adult congenital heart disease unit. <h3>Patients</h3> 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). <h3>Interventions</h3> Cardiovascular MRI (1.5T) and cardiopulmonary exercise test. <h3>Main outcome measures</h3> Biventricular volumes and function; exercise capacity. <h3>Results</h3> 20 patients had RVEDVi below, and 35 had RVEDVi above 150 ml/m², at time of referral. In the &gt;150 ml/m² group, fractional pulmonary regurgitation was higher (41±8 vs 31±8%, p&lt;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/m², p&lt;0.001) in the &gt;150 ml/m² 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 VO₂ peak: 84±17 vs 87±12%). <h3>Conclusions</h3> 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.