title: Exercise capacity in single-ventricle patients after Fontan correlates with haemodynamic energy loss in TCPC.
abstract: OBJECTIVE
  Elevated energy loss in the total cavopulmonary connection (TCPC) is hypothesised to have a detrimental effect on clinical outcomes in single-ventricle physiology, which may be magnified with exercise. This study investigates the relationship between TCPC haemodynamic energy dissipation and exercise performance in single-ventricle patients.
  
  
  METHODS
  Thirty consecutive Fontan patients with TCPC and standard metabolic exercise testing were included. Specific anatomies and flow rates at rest and exercise were obtained from cardiac MR (CMR) and phase-encoded velocity mapping. Exercise CMR images were acquired immediately following supine lower limb exercise using a CMR-compatible cycle ergometer. Computational fluid dynamics simulations were performed to determine power loss of the TCPC anatomies using in vivo anatomies and measured flows.
  
  
  RESULTS
  A significant negative linear correlation was observed between indexed power loss at exercise and (a) minute oxygen consumption (r=-0.60, p<0.0005) and (b) work (r=-0.62, p<0.0005) at anaerobic threshold. As cardiac output increased during exercise, indexed power loss increased in an exponential fashion (y=0.9671x(3.0263), p<0.0001).
  
  
  CONCLUSIONS
  This is the first study to demonstrate the relationship between power loss and exercise performance with the TCPC being one of the few modifiable factors to allow for improved quality of life. These results suggest that aerobic exercise tolerance in Fontan patients may, in part, be a consequence of TCPC power loss.
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, USA.
authors.forename: Reza H
authors.initials: RH
authors.lastname: Khiabani
authors.affiliation: Division of Cardiology and Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Whitehead
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, USA.
authors.forename: David
authors.initials: D
authors.lastname: Han
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Restrepo
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, USA.
authors.forename: Elaine
authors.initials: E
authors.lastname: Tang
authors.affiliation: Westat, Rockville, Maryland, USA.
authors.forename: James
authors.initials: J
authors.lastname: Bethel
authors.affiliation: Division of Cardiology and Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Paridon
authors.affiliation: Division of Cardiology and Department of Radiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Fogel
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology & Emory University, Atlanta, Georgia, USA.
authors.forename: Ajit P
authors.initials: AP
authors.lastname: Yoganathan
mesh_terms: D000293:Adolescent; D000328:Adult; D001783:Blood Flow Velocity; D002302:Cardiac Output; D019468:Disease Management; D005080:Exercise Test / Q000379:methods; D005081:Exercise Therapy / Q000379:methods; D017079:Exercise Tolerance; D005260:Female; D018729:Fontan Procedure / Q000379:methods / Q000523:psychology / Q000534:rehabilitation; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery; D006352:Heart Ventricles / Q000002:abnormalities*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D066230:Patient-Specific Modeling; D010414:Pennsylvania; D005082:Physical Exertion; D011183:Postoperative Complications / Q000175:diagnosis / Q000503:physiopathology / Q000517:prevention & control; D011788:Quality of Life
keywords: CONGENITAL HEART DISEASE