Objective Patients with tetralogy of Fallot (ToF) have limited pulmonary blood flow before corrective surgery and ongoing dysfunction of the pulmonary valve and right ventricle throughout life leading to lower exercise capacity and lung volumes in many patients. Inhalation training can increase lung volumes, improve pulmonary blood flow and consequently exercise capacity. This study tests whether home-based daily breathing training improves exercise capacity and lung volumes.
Methods From February 2017 to November 2018, 60 patients (14.7±4.8 years, 39% female) underwent spirometry (forced vital capacity (FVC); forced expiratory volume in 1 s (FEV1)), cardiopulmonary exercise testing (peak oxygen uptake (peak O2)) and breathing excursion measurement. They were randomised into immediate breathing exercise or control group (CG) and re-examined after 6 months. The CG started their training afterwards and were re-examined after further 6 months. Patients trained with an inspiratory volume-oriented breathing device and were encouraged to exercise daily. The primary endpoint of this study was the change in peak O2. Results are expressed as mean±SEM (multiple imputations).
Results In the first 6 months (intention to treat analysis), the training group showed a more favourable change in peak O2 (Δ0.5±0.6 vs −2.3±0.9 mL/min/kg, p=0.011), FVC (Δ0.18±0.03 vs 0.08±0.03 L, p=0.036) and FEV1 (Δ0.14±0.03 vs −0.00±0.04 L, p=0.007). Including the delayed training data from the CG (n=54), this change in peak O2 correlated with self-reported weekly training days (r=0.282, p=0.039).
Conclusions Daily inspiratory volume-oriented breathing training increases dynamic lung volumes and slows down deconditioning in peak O2 in young patients with repaired ToF.
- heart defects
- tetralogy of Fallot
- cardiac rehabilitation
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Contributors JH: conception/design of the study, data collection and analysis, and writing of the manuscript; JR: ideas on testing and critical revision on the manuscript; RO and PE: critical revision of the manuscript and supervision; AH: conception/design of the study, data analysis, writing of manuscript and supervision. All authors approved the final manuscript. JH and AH are responsible for the overall content as guarantors.
Funding The study was funded by an unrestricted grant from the 'Stiftung KinderHerz'. We declare that the results of the study are presented honestly and without fabrication, falsification or inappropriate data manipulation according to the registered protocol. Additionally, we would like to thank the whole team that was crucially responsible for its success. Parts of the study have been presented at the congresses CPX international 2019 and 'Deutsche Gesellschaft für Pädiatrische Kardiologie und Angeborene Herzfehler e.V.' 2020.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Patient consent for publication Not required.
Ethics approval The local ethical board of the Technical University of Munich approved the study (project number: 4/17S).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available.