Background Whilst pulmonary valve replacement (PVR) in patients with repaired tetralogy of Fallot (rTOF) is shown to provide symptomatic benefit and reduction of right ventricular (RV) volumes, there are scarce data on the rate of ventricular mechanical and biological adaptation. We aimed to assess early and late post-PVR volumetric and functional changes.

Methods and Results Patients with rTOF (≥16 years) for PVR were prospectively recruited for Cardiovascular Magnetic Resonance (CMR): pre-PVR (pPVR), early post-PVR at median 6 days (ePVR) and late post-PVR at median 3 years (mPVR).

Fifty-seven patients with rTOF (mean age 35.8 ± 10.1 years, 38 male) were included. There was an acute reduction in indexed RV end-diastolic (EDVi), end-systolic (ESVi) volumes and mass early post-PVR, which was sustained at latest time point (RVEDVi pPVR 156.1 ± 41.9ml/m² vs ePVR 104.9 ± 28.4ml/m² vs mPVR 104.2 ± 34.4ml/m² and RVESVi pPVR 74.9 ± 26.2ml/m² vs ePVR 57.4 ± 22.7ml/m² vs mPVR 50.5 ± 21.7ml/m²;p < 0.01). Seventy percent of patients achieved postoperative normal range diastolic and systolic RV volumes which were predicted by a preoperative RVEDVi≤158ml/m²and RVESVi≤82ml/m². PVR produced a stepwise reduction in RVESVi (load independent variable) together with an improvement in corrected RVEF after restoring valve competency (which is load dependent). There was also a modest but significant improvement of LVEF, as well as reverse right atrial remodelling.

Conclusions Cardiac remodelling is generally regarded as a gradual process post-PVR. We demonstrate for the first time that the major improvement in RV volumes seen at midterm follow-up have already taken place within days after surgery. This occurs with an apparent transient impairment of RVEF, although corrected RVEF more easily illustrates the immediate effect of PVR. However, RVESVi may be a more appropriate, load-independent marker that better reflects the early and sustained benefit of PVR on RV contractility.