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Updated: May 9, 2026
Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles
Published on: November 1, 2012
Skeletal muscle abnormalities and exercise capacity in adults with a Fontan circulation
Rachael Cordina1, Shamus O'Meagher, Haslinda Gould
1Department of Cardiology, Royal Prince Alfred Hospital, , Sydney, New South Wales, Australia.
Insights
Adults with Fontan circulation have reduced skeletal muscle mass and impaired muscle metabolism. These findings highlight potential muscle wasting and metabolic issues in this patient group, impacting exercise capacity.
Area of Science:
- Cardiology
- Exercise Physiology
- Muscle Biology
Background:
- The peripheral muscle pump is crucial for cardiac filling during exercise, particularly in individuals with Fontan circulation.
- Muscle-wasting syndromes are known in acquired heart failure but are understudied in Fontan patients.
Purpose of the Study:
- To investigate skeletal muscle mass and metabolic abnormalities in adults with Fontan circulation.
- To determine if Fontan adults exhibit reduced lean mass or metabolic dysfunction.
Main Methods:
- Sixteen Fontan adults underwent cardiopulmonary exercise testing and DXA for lean mass quantification.
- Calf muscle phosphorus-31 magnetic resonance spectroscopy was used to assess muscle metabolism in a subset of Fontan adults and healthy controls.
Main Results:
- Fontan adults showed significantly reduced skeletal muscle mass compared to reference data (Z-score -1.46).
- Reduced muscle mass correlated with lower peak oxygen consumption (VO2 max).
- Muscle aerobic capacity, indicated by phosphocreatine resynthesis, was impaired in Fontan adults versus controls.
Conclusions:
- Adults with Fontan circulation exhibit reduced skeletal muscle mass.
- Intrinsic muscle metabolic abnormalities are present in Fontan adults.
- These findings suggest a need for further investigation into muscle health in Fontan patients.
Objectives:
The peripheral muscle pump is key in promoting cardiac filling during exercise, especially in subjects who lack a subpulmonary ventricle (the Fontan circulation). A muscle-wasting syndrome exists in acquired heart failure but has not been assessed in Fontan subjects. We sought to investigate whether adults with the Fontan circulation exhibit reduced skeletal muscle mass and/or metabolic abnormalities.
Design And Patients:
Sixteen New York Heart Association Class I/II Fontan adults (30±2 years) underwent cardiopulmonary exercise testing and lean mass quantification with dual x-ray absorptiometry (DXA); eight had calf muscle (31)P magnetic resonance spectroscopy as did eight healthy age-matched and sex-matched controls. DXA results were compared with Australian reference data.
Setting:
Single tertiary referral centre.
Results:
Peak VO2 was 1.9±0.1 L/min (66±3% of predicted values). Skeletal muscle mass assessed by relative appendicular lean mass index was significantly reduced compared with age-matched and sex-matched reference values (Z-score -1.46±0.22, p<0.0001). Low skeletal muscle mass correlated with poorer VO2 max (r=0.67, p=0.004). Overall, skeletal muscle mass T-score (derived from comparison with young normal reference mean) was -1.47±0.21; 4/16 Fontan subjects had sarcopenic range muscle wasting (T-score <-2.0) and 9/16 had less marked, but clinically significant wasting (T-score <-1.0 but ≥-2.0). Muscle aerobic capacity, measured by the rate constant (k) of postexercise phosphocreatine resynthesis, was significantly impaired in Fontan adults versus controls (1.48±0.13 vs 2.40±0.33 min(-1), p=0.02).
Conclusions:
Fontan adults have reduced skeletal muscle mass and intrinsic muscle metabolic abnormalities.
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