title: Longitudinal assessment of cardiovascular exercise performance after pediatric heart transplantation.
abstract: BACKGROUND
  No existing longitudinal data document exercise performance after pediatric heart transplantation. We report the exercise performance findings from the longitudinal study of pediatric heart transplantation patients and the association of aerobic capacity with echocardiographic measures of graft function.
  
  
  METHODS
  We performed a retrospective analysis of 28 children after heart transplantation who underwent 87 exercise tests and echocardiograms. Subjects exercised using graded cycle or treadmill protocols. Maximal oxygen consumption (VO2), physical working capacity, peak heart rate, and anaerobic threshold were evaluated. To measure systolic and diastolic function, shortening fraction and mitral valve pressure half-time (PHT) respectively, were obtained by echocardiography.
  
  
  RESULTS
  The average age at transplantation was 10.9 +/- 5.6 years, at initial exercise test was 13.8 +/- 5.0 years, and at final exercise test was 15.8 +/- 5.2 years. Percent-predicted values at the initial exercise test were VO2, 59.3%; physical working capacity, 60.2%; and peak heart rate, 75.8%; these remained similarly decreased at the final exercise test. Shortening fraction and PHT were within normal limits, but PHT was significantly greater at final test (p < 0.05). The relationship of VO2% with time was statistically significant, described by a quadratic equation that included initial VO2% and time from heart transplantation. This relationship remained significant when the shortening fraction (p < .05) but not PHT was added as a covariate in the equation.
  
  
  CONCLUSIONS
  Exercise performance after pediatric heart transplantation is impaired and, despite an initial improvement, declines over time. This can be explained by increasing diastolic dysfunction independent of donor graft age. If confirmed, these findings point the direction to further research aimed at limiting this aerobic capacity decline after heart transplantation.
authors.affiliation: Division of Cardiology, The Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA. davisju@email.chop.edu
authors.forename: Julie A
authors.initials: JA
authors.lastname: Davis
authors.forename: Michael G
authors.initials: MG
authors.lastname: McBride
authors.forename: Maryanne R K
authors.initials: MR
authors.lastname: Chrisant
authors.forename: Sujata M
authors.initials: SM
authors.lastname: Patil
authors.forename: Brian D
authors.initials: BD
authors.lastname: Hanna
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Paridon
mesh_terms: D000328:Adult; D002311:Cardiomyopathy, Dilated / Q000601:surgery; D002648:Child; D003330:Coronary Vessel Anomalies / Q000601:surgery; D015150:Echocardiography, Doppler; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006330:Heart Defects, Congenital / Q000601:surgery; D016027:Heart Transplantation / Q000000981:diagnostic imaging / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015233:Models, Statistical; D010101:Oxygen Consumption; D011184:Postoperative Period; D012189:Retrospective Studies