Laohachai K, Winlaw D, Selvadurai H, Gnanappa GK, d’Udekem
Y, Celermajer D, Ayer J

J Am Heart Assoc. 2017 Aug 21;6(8). pii: e005750. doi: 10.1161/JAHA.117.005750.

BACKGROUND: Patients with a Fontan circulation have reduced exercise capacity and
respiratory muscle strength. Inspiratory muscle training (IMT) improves exercise
capacity and quality of life in adults with heart failure. We assessed whether
6 weeks of a home-based program of IMT improves inspiratory muscle strength and
the ventilatory efficiency of exercise in adolescent patients with a Fontan
circulation.
METHODS AND RESULTS: Twenty-three adolescent participants (aged 16±2 years) with
a Fontan circulation underwent 6 weeks of IMT for 30 minutes daily. Respiratory
muscle strength (maximal inspiratory pressure and expiratory pressure), lung
function, and exercise capacity (cardiopulmonary exercise testing) were assessed.
Fourteen of 23 participants also underwent exercise cardiac magnetic resonance
imaging to examine the effects of IMT on cardiac output and systemic and
pulmonary blood flow. Six weeks of IMT improved maximal inspiratory pressure by
36±24 cm H2O (61±46%) with no change in maximal expiratory pressure. Ventilatory
efficiency of exercise improved after 6 weeks of IMT (from 34.2±7.8 to 32.2±5.6,
P=0.04). In those who underwent exercise cardiac magnetic resonance imaging, IMT
increased resting cardiac output (from 4.2±1.2 to 4.5±1.0 L/min, P=0.03) and
ejection fraction (from 50.1±4.3 to 52.8±6.1%, P=0.03).
CONCLUSIONS: Six weeks of IMT is associated with improved inspiratory muscle
strength, ventilatory efficiency of exercise, and resting cardiac output in young
Fontan patients. IMT may be a simple beneficial addition to the current
management of Fontan patients, potentially reducing exercise intolerance and
long-term morbidity and mortality.