Exercise capacity and biventricular function in adult patients with repaired tetralogy of Fallot

BackgroundAdult patients with repaired tetralogy of Fallot (rTOF) often have diminished exercise capacity. The primary objective of this study was to examine whether abnormalities of biventricular function play a role in exercise limitation in patients with rTOF.MethodsThis was a retrospective review of 99 adult patients with rTOF. Right ventricular (RV) and left ventricular (LV) function were assessed echocardiographically using the myocardial performance index (MPI). Maximal oxygen consumption (VO2 Max) was measured during a level 1 cardiopulmonary exercise test.ResultsThe mean age of the cohort was 34 ± 11 years (50% females). Although most of the patients reported good functional capacity, the peak Vo2max was decreased at 22 ± 6 mL/kg per minute (66% ± 13% predicted Vo2max for age and sex). The mean RV and LV MPI were 0.30 ± 0.07 and 0.42 ± 0.09, respectively. In the multivariate model, higher RV MPI (P = .04) and LV MPI (P = .005) values, representing impaired ventricular function, were associated with diminished Vo2max. There was a significant correlation between the RV and LV MPI (r = 0.54, P = .001).ConclusionsImpairment of RV and LV function, as measured by MPI, is associated with diminished exercise capacity in patients with repaired tetralogy of Fallot. Furthermore, there is a linear relationship between the RV and LV function suggesting that ventricular interactions are contributing to the limited exercise capacity in this group of patients. Strategies aimed at preserving biventricular function or improving adverse ventricular interactions could help to improve functional capacity in these patients.