Abstract 14333: Respiratory Muscle Dysfunction in Patients With Congenital Heart Disease
Introduction: Patients with heart failure from acquired cardiomyopathy (ischemic or dilated) often exhibit a generalized myopathy with respiratory muscles being particularly susceptible. Decreased inspiratory muscle strength in patients with heart failure is an independent predictor for adverse events and a target for specific treatment. Although the primary defect in patients with congenital heart disease (CHD) is not a myopathic but a structural / anatomical defect, many CHD patients develop a syndrome comparable to heart failure from acquired cardiomyopathy. In this study of adults with complex CHD we therefore sought to assess the presence and extent of respiratory and skeletal muscle weakness.
Methods: Forty-one consecutive adults with complex CHD (16 repaired tetralogy of Fallot, 11 Fontan patients and 14 transposition complexes with systemic right ventricles) and 10 healthy controls were included. Maximal inspiratory pressures (MIPs), handgrip strength (HGS), lung volumes and exercise capacity (peak VO2) were measured.
Results: In all CHD-subgroups, MIPs and HGS were significantly lower compared to healthy controls (MIPs: 77 ± 27% vs. 106 ± 28% predicted, p = 0.003; HGS: 72 ± 15% vs. 93 ± 14% predicted, p < 0.001) but were not significantly different between individual CHD-subgroups (see Table). None of the controls but 17% of CHD patients had MIPs below 50% predicted. MIP correlated with FEV1 (r = 0.44, p = 0.001) but not with total lung capacity (r = 0.07, p = 0.7). Correlation between MIP and peak VO2 was weak (r = 0.33, p = 0.03) and there was no correlation with systemic ventricular ejection fraction (r = 0.01, p = 1.0).
Conclusion: Respiratory muscle weakness is common in patients with complex CHD and seems to be independent of the underlying defect. It may have an important impact on dynamic lung volumes. Adults with CHD and reduced respiratory muscle strength may benefit from specific respiratory muscle training to improve exercise capacity and quality of life.
- © 2010 by American Heart Association, Inc.