Exercise capacity among patients with tetralogy of Fallot who underwent transannular and non-transannular repair

Background: Tetralogy of Fallot (TOF) repair using a transannular patch (TAP) may lead to varying degrees of pulmonary insufficiency (PI) due to loss of pulmonary valve integrity. The subsequent right ventricle (RV) dilatation and dysfunction over time may directly or indirectly affect exercise capacity. Methods: Fifty-six patients who had undergone intracardiac repair of TOF between January 2010 and December 2015 were subjected to exercise stress testing. Twenty-six patients underwent TAP placement, and 30 patients did not. The modified BRUCE protocol was used on a standard cycle ergometer for exercise testing. The total duration of exercise, the heart rate achieved at the peak of exercise, the heart rate reserve, and the maximal oxygen consumption (VO 2 max) in patients in the TAP repair group were compared to those in the non-TAP group. Results: Patients with a TAP had significantly lower exercise capacity compared to those without TAP. Both the total duration of exercise, the heart rate achieved at the peak of exercise, the heart rate reserve, and the VO 2 max were higher in patients in the TAP repair group compared to the non-TAP group. The VO 2 max in the non-TAP group was higher (37.47 ± 5.7 ml/kg/min) than that of the TAP group (30.5 ± 5.0 ml/kg/min) ( P = 0.02). Multivariate analysis showed that neither TAP nor PI was predictive of exercise capacity. However, we found that RV function and overall health status were significant predictors of exercise capacity. Conclusions: The non-TAP group had a better VO 2 max, heart rate recovery time, and heart rate reserve than the TAP group at 5 years of follow-up.