title: Only slow decline in exercise capacity in the natural history of patients with congenital heart disease: a longitudinal study in 522 patients.
abstract: OBJECTIVE
  Exercise studies in patients with congenital heart disease (CHD) suggest that exercise capacity declines progressively. This study aims to assess the natural history of exercise capacity in patients with CHD from serial cardiopulmonary exercise tests (CPETs) and to identify factors that are associated with the rate of decrease.
  
  
  METHODS
  From July 2001-August 2012 we included all patients with CHD who had two CPETs separated by at least six months. Patients with any kind of intervention (surgery, catheter intervention, or change in medication) between the two tests were excluded.
  
  
  RESULTS
  In 522 patients (24.8 ± 10.2 years, 215 female) peak oxygen uptake (VO2) was reduced to 80.0 ± 20.7% predicted and declined significantly during a mean follow-up of 2.5 ± 1.8 years to 78.1 ± 20.4% predicted (p < 0.0001). The annual declining rate of peak VO2 was only -1.01 ± 6.83% points per year. Higher peak oxygen pulse (% predicted) (r = -0.230; p < 0.0001), higher peak VO2 (% predicted) (r = -0.213; p < 0.0001) at baseline testing and the presence of a pacemaker (r = -0.095; p = 0.031) were only weakly associated with a more rapid decline in peak VO2 (% predicted) over time. The decline was independent from diagnosis, heart defect severity, systemic ventricular morphology and age.
  
  
  CONCLUSIONS
  There was a progressive, but slow, decline in the natural history of exercise capacity in all kind of patients with CHD. Except for having a pacemaker, we could not find any factors associated with this decline.
authors.affiliation: Department of Pediatric Cardiology and Congenital Heart Disease, Technische Universität München, Germany j.mueller@tum.de.
authors.forename: Jan
authors.initials: J
authors.lastname: Müller
authors.affiliation: Department of Pediatric Cardiology and Congenital Heart Disease, Technische Universität München, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Ewert
authors.affiliation: Department of Pediatric Cardiology and Congenital Heart Disease, Technische Universität München, Germany.
authors.forename: Alfred
authors.initials: A
authors.lastname: Hager
mesh_terms: D000293:Adolescent; D000328:Adult; D002304:Cardiac Pacing, Artificial; D018450:Disease Progression; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D010101:Oxygen Consumption; D010138:Pacemaker, Artificial; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013997:Time Factors; D055815:Young Adult
keywords: Congenital heart disease; exercise capacity; exercise testing; natural history; peak oxygen uptake; serial study