Muscle function in adults with congenital heart disease

Background The aim was to assess muscle function in a sample of Swedish adult men and women with congenital heart disease (ACHD) and to compare the results with published reference values in healthy adults. Methods and results From April 2009 to December 2010, 762 adult outpatients were assessed for their suitability and individual need for tests of physical fitness. The patients performed five muscle function tests, two isotonic tests and three isometric tests. Of the 762 patients, 315 (41.3%) patients performed the tests. Patients with ACHD had lower isotonic muscle function compared to healthy reference values. In the heel lift test, men with ACHD performed at 63% and women at 58% of the healthy reference values and in the shoulder flexion test the corresponding performance level was 60% for men with ACHD and 85% for the women. Multiple regression analyses showed that NYHA class II–IV was a significant predictor for a lower isotonic muscle function i.e. heel lift in women (p<0.001) and men (p=0.05) and in shoulder flexion (p<0.001) in women, as well as in isometric knee extension (p=0.04) and isometric shoulder abduction (p<0.001) in women. Conclusion This is the first report of muscle function in a broad and unselected group of patients with ACHD. Our data shows that patients with ACHD have lower isotonic muscle function. The impacts of low muscle function in activities of daily living and the question of whether muscle function could be improved with exercise training need further investigation.