title: Energy transfer ratio as a metric of right ventricular efficiency in repaired congenital heart disease.
abstract: OBJECTIVE
  With the success of early repair, continued functional assessment of repaired congenital heart disease is critical for improved long-term outcome. Pulmonary regurgitation, which is one of the main postoperative sequelae of congenital heart disease involved with the right ventricle (RV) such as tetralogy of Fallot and transposition of the great arteries, results in progressive RV dilatation coupled with pulmonary artery (PA) obstruction causing elevated RV pressures. The appropriate timing of intervention to correct these postoperative lesions remains largely subjective. In the present study, we evaluated an energy-based end point, namely energy transfer ratio (eMPA ), to assess the degree of RV and PA inefficiency in a group of congenital heart disease patients with abnormal RV-PA physiology.
  
  
  METHODS
  Eight patients with abnormal RV-PA physiology and six controls with normal RV-PA physiology were investigated using a previously validated technique that couples cardiac magnetic resonance imaging and invasive pressure measurements.
  
  
  RESULTS
  The mean eMPA of the patient group (0.56 ± 0.33) was significantly lower (P <.04) than that of the control group (1.56 ± 0.85), despite the fact that the patient group had a significantly higher RV stroke work indexed to body surface area (RV SWI ) than the control group (0.205 ± 0.095 J/m(2) vs. 0.090 ± 0.038 J/m(2) ; P <.02).
  
  
  CONCLUSIONS
  We determined that the patients had inefficient RV-PA physiology due to a combination of RV dilatation with pulmonary regurgitation and RV outflow obstruction leading to an elevated end-systolic pressure. Using coupled magnetic resonance imaging and invasive pressure measurements, eMPA is determined to be a sensitive energy-based end point for measuring RV-PA efficiency. It may serve as a diagnostic end point to optimize timing of intervention.
authors: Mechanical Engineering, School of Dynamic Systems, University of Cincinnati, Cincinnati, OH 45221, USA.
authors: Namheon
authors: N
authors: Lee
authors: Ashish
authors: A
authors: Das
authors: Michael
authors: M
authors: Taylor
authors: Kan
authors: K
authors: Hor
authors: Rupak K
authors: RK
authors: Banerjee
mesh_terms: D000293:Adolescent; D001830:Body Surface Area; D006328:Cardiac Catheterization; D006348:Cardiac Surgical Procedures; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004735:Energy Transfer; D005260:Female; D006330:Heart Defects, Congenital / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D006352:Heart Ventricles / Q000002:abnormalities / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics; D006801:Humans; D017380:Hypertrophy, Right Ventricular / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008955:Models, Cardiovascular; D011651:Pulmonary Artery / Q000002:abnormalities / Q000503:physiopathology / Q000601:surgery*; D011665:Pulmonary Valve Insufficiency / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D013318:Stroke Volume; D013997:Time Factors; D061665:Time-to-Treatment; D016896:Treatment Outcome; D016278:Ventricular Function, Right; D014694:Ventricular Outflow Obstruction / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D017725:Ventricular Pressure; D055815:Young Adult
keywords: Congenital Heart Disease; Energy-based End Point; Pulmonary Insufficiency