Objective: We tested the hypothesis that restrictive right ventricular (RV) physiology is prevalent and related to RV fibrosis and exercise capacity in patients after biventricular repair of pulmonary atresia and intact ventricular septum (PAIVS).
Methods: Twenty-seven patients aged 16.5+/-5.6 years after biventricular repair of PAIVS were recruited. Restrictive RV physiology was defined by presence of antegrade diastolic pulmonary flow and RV fibrosis assessed by late gadolinium enhancement (LGE) cardiac magnetic resonance. Their RV function was compared with that of 27 healthy controls and related to RV LGE score and exercise capacity.
Results: Compared with controls, PAIVS patients had lower tricuspid annular systolic and early diastolic velocities, RV global longitudinal systolic strain, systolic strain rate, and early and late diastolic strain rates (all p<0.05). Twenty-two (81%, 95% CI 62-94%) PAIVS patients demonstrated restrictive RV physiology. Compared to those without restrictive RV physiology (n=5), these 22 patients had lower RV global systolic strain, lower RV systolic and early diastolic strain rates, higher RV LGE score, and greater percent predicted maximum oxygen consumption (all p<0.05). The RV LGE score correlated negatively with RV global longitudinal early diastolic strain rate (r=-0.40, p=0.038), and positively with age (r=0.43, p=0.024), exercise duration (r=0.45, p=0.029), and percent predicted maximum oxygen consumption (r=0.43, p=0.042).
Conclusion: Restrictive RV physiology is prevalent in patients after biventricular repair of PAIVS, while the corresponding RV diastolic dysfunction is related to the magnitude of RV fibrosis and associated with better exercise capacity.