Objective:

To examine the associations between hemodynamic and pulmonary variables and cardiorespiratory fitness (CRF) in adolescents with Fontan circulation, highlighting the significance of these associations for clinical management.

Key Findings:

• Higher ventricular end-diastolic pressure (VEDP) and transpulmonary pressure gradient (TPG) were associated with lower CRF, indicating potential targets for intervention.
• Impaired diffusing capacity (DLCO/VA) correlated with reduced CRF, suggesting the need for pulmonary function monitoring.
• Height was identified as an important determinant of V̇O₂peak, emphasizing the role of somatic growth in CRF.

Interpretation:

The study highlights the multifactorial nature of reduced CRF in adolescents with Fontan circulation, emphasizing the role of hemodynamic inefficiencies and pulmonary function, which may inform future research and clinical guidelines.

Limitations:

• Limited generalizability due to the specific cohort of adolescents with Fontan circulation, which may affect the applicability of findings to broader populations.
• Potential biases in self-reported measures and the observational nature of the study, which could influence the reliability of the results.

Conclusion:

Understanding the factors affecting CRF can improve risk stratification and management strategies for adolescents with Fontan circulation, ultimately enhancing patient outcomes.