title: Exercise tolerance in patients with Ebstein's anomaly.
abstract: OBJECTIVE
  The purpose of this study was to identify the determinants of exercise tolerance in patients with Ebstein's anomaly.
  
  
  BACKGROUND
  Patients with Ebstein's anomaly of the tricuspid valve may have exercise limitation that improves after surgical repair.
  
  
  METHODS
  One hundred seventeen patients performed cycle ergometry for a total of 124 tests (preoperative test in 76 patients, postoperative test in 23, test but no operation in 18, preoperative and postoperative test in 7). Multiple linear regression analysis was used to identify predictors of maximal oxygen uptake, oxygen saturation and heart rate at peak exercise.
  
  
  RESULTS
  Age at the time of exercise ranged from 6 to 60 years (median 15). An atrial septal defect was present in 67 patients (88%) preoperatively. Compared with the preoperative group, the postoperative group had significantly higher maximal oxygen uptake (mean [+/- SD] 20.5 +/- 7.4 vs. 25.3 +/- 7.0 ml/kg body weight per min, p = 0.006). Postoperative rest and exercise blood oxygen saturation was higher than that measured preoperatively (p = 0.0001). Six of seven patients tested before and after the operation showed improved exercise tolerance. Preoperatively, major predictors of maximal oxygen uptake were oxygen saturation at rest (p = 0.01) and age (p = 0.0001). Preoperatively, the major predictor of oxygen saturation at peak exercise was rest oxygen saturation (p = 0.0001), and major predictors of peak exercise heart rate were rest heart rate (p = 0.01) and rest oxygen saturation (p = 0.01). In the postoperative group, predictors of maximal oxygen uptake included age at exercise testing, male gender and heart size.
  
  
  CONCLUSIONS
  Definitive operation for Ebstein's anomaly results in improved exercise tolerance. Before the operation, rest oxygen saturation is the major predictor of exercise tolerance, oxygen saturation at peak exercise and peak heart rate. Postoperatively, age, gender and heart size influenced maximal oxygen uptake.
authors.affiliation: Department of Pediatrics, Covenant Medical Center, Waterloo, Iowa, USA.
authors.forename: S G
authors.initials: SG
authors.lastname: MacLellan-Tobert
authors.forename: D J
authors.initials: DJ
authors.lastname: Driscoll
authors.forename: C D
authors.initials: CD
authors.lastname: Mottram
authors.forename: D W
authors.initials: DW
authors.lastname: Mahoney
authors.forename: P C
authors.initials: PC
authors.lastname: Wollan
authors.forename: G K
authors.initials: GK
authors.lastname: Danielson
mesh_terms: D000293:Adolescent; D000328:Adult; D002302:Cardiac Output; D002648:Child; D004437:Ebstein Anomaly / Q000150:complications / Q000503:physiopathology*; D004562:Electrocardiography; D005080:Exercise Test; D017079:Exercise Tolerance; D005541:Forced Expiratory Volume; D006339:Heart Rate; D006344:Heart Septal Defects, Atrial / Q000150:complications / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D012189:Retrospective Studies; D014797:Vital Capacity