Increased Exercise Capacity after Inspiratory Ventilatory Training in Young Patients with the Repaired Tetralogy of Fallot: A Randomized Controlled Trial

Objectives: Patients with the tetralogy of Fallot (TOF), a cyanotic right heart obstructive congenital heart disease, have limited blood flow to the lungs before corrective surgery and ongoing dysfunction of the pulmonary valve and right ventricle leading to lower exercise capacity and impaired lung volumes in many patients. Training of deep inhalation may increase lung volumes, improve pulmonary blood flow, and, consequently, exercise capacity. This study examined the effects of a volume-oriented inspiratory ventilatory training in patients with repaired TOF on exercise capacity and lung volumes.

Methods: From February 2017 to November 2018 54 patients (age at inclusion: 14.7 ± 4.8 years, 39% female) underwent spirometry (forced vital capacity [FVC] and forced expiratory volume within the first second [FEV1]) and a cardiopulmonary exercise test (CPET: peak oxygen uptake, VO₂ peak). They were randomized into immediate ventilatory training or a control group with training after a delay of 6 months. Patients were reexamined 6 months after randomization, as well as after their training.

Result: In the first 6 months (intention to treat analysis), the training group increased in exercise capacity (&Δ 0.5 ± 3.5 vs. &−2.3 ± 4.8 mL/min/kg, p = 0.015), FVC (&Δ 0.18 ± 0.17 vs. 0.07 ± 0.16 L, p = 0.022), and FEV1 (&Δ 0.14 ± 0.17 vs. &−0.01 ± 0.17 L, p = 0.002). Including the delayed training data from the control group (perprotocol analysis), there was a significant increase in peak VO₂ (&Δ 1.2 ± 3.6 mL/min/kg, p = 0.017) correlating with self-reported training days per week (r = 0.322, p = 0.026). FVC and FEV1 also improved significantly (&ΔFVC: 0.17 ± 0.20 L, p < 0.001; &ΔFEV1: 0.15 ± 0.19 L, p < 0.001) but both showed no correlation toward training days per week.

Conclusion: Young patients with repaired TOF benefit from a 6-month inspiratory ventilatory training with regard to exercise capacity and ventilatory function.