- Breathing training improves exercise capacity in patients with tetralogy of Fallot: a randomised trial.
Hock J, Remmele J, Oberhoffer R, Ewert P, Hager A.
Heart. 2021 Mar 18:heartjnl-2020-318574. doi: 10.1136/heartjnl-2020-318574. Online ahead of print.
Take Home Points:
- Inspiratory training increases lung volumes and slows down the deconditioning in exercise capacity.
- Increased exercise frequency increased the degree of improvement.
Commentary from Dr. Blanche Cupido (Cape Town, South Africa), chief section editor of ACHD Journal Watch: Many Tetralogy of Fallot (TOF) patients experience late complications, frequently in the form of pulmonary disease or RV dysfunction. Cardiopulmonary exercise testing form part of the long term follow up strategy to determine exercise tolerance objectively and aid decision-making regarding RV deterioration. Many of these patients have an impairment of lung function (restrictive pattern) correlating to their reduced exercise capacity. Previous studies showed that physical training can improve physical endurance capacity in children and young adults with TOF.
This study from a single center in Munich, assessed whether a home-based volume-oriented inspiratory breathing training increases exercise capacity (assessed by peak oxygen uptake). The design was a prospective randomized non-blinded clinical trial, with the primary outcome of improvement in exercise capacity as measured by peak oxygen uptake (peak VO2).The secondary outcomes were lung volumes and thoracic flexibility.
Adult patients were enrolled between February and November 2017. Patients included had a repaired TOF (DORV-type and pulmonary atresia with VSD were included too). Patients with obstructive lung disease, a recent medication change (within 3 months), recent cardiac catheterization (within 6 months), recent heart surgery (within the last 12 months), planned surgery within the next 36 months, severe heart failure, frequent arrythmias, the presence of a pacemaker and a current lung infection. All patients had echocardiography, spirometry, breathing excursion and a cardiopulmonary exercise test (CPET). Patients were randomized to either start their training immediately or after 6 months.
All patients had an exhausting and a symptom-limited CPET. A volume-oriented respiratory training was performed using the Coach2 Incentive spirometer lung trainer. This device encourages a constant slow long inspiration without flow resistance. It has not effect on exhalation. Training commenced at 40% of measured FVC – 1-3 sets of 10-30 reps were done daily.
Thirty patients were assigned randomly to the training group and 30 to the control group. There was no significant difference in terms of age, BMI, restrictive lung function, exercise capacity at baseline of age of repair in the 2 groups.
Initially the values of lung capacity did not differ between the 2 groups. The training group had a significantly increased change in peak VO2 (+0.5 cf -2.1 , p=0.011), an increase in FVC (0.18 vs 0.08, p=0.036) and an increase in FEV1 (0.14 vs 0.00, p=0.007) (figure 2 above). No significant changes occurred with respect to breathing excursion.
In those who self-reported to train 7 days a week over the 6 month period, a significant improvement in peak VO2 was notes (see figure 3 below). There was a positive correlation between self-reported training and peak VO2 (r=0.282, p=0.039).