title: Cardiorespiratory response to exercise in children after modified fontan operation.
abstract: OBJECTIVE
  Examination of exercise function of Fontan patients and comparison with healthy control subjects.
  
  
  METHODS
  Fourteen patients (6 males, 8 females; age: 5.7-17 years, mean 8.1 years) after Fontan repair in New York Heart Association (NYHA) class I with rest O(2)sat > 85% requiring no cardiovascular medications performed graded exercises on a treadmill 0.5-3.2 years postoperatively (mean 1.8 years). During the tests the heart and respiratory rate, blood pressure, oxygen uptake, carbon dioxide production, minute ventilation, tidal volume and O(2)sat were recorded. Spirometry was performed before and during exercise.
  
  
  RESULTS
  The peak VO(2)max in Fontan patients was significantly reduced compared with controls (p = 0.0002). Other parameters: anaerobic threshold (p = 0.0001); pulsO(2) (p = 0.00005); peak minute ventilation (p = 0.0014); physiological dead space to tidal volume ratio at peak exercise (p = 0.0004); maximal work rate (p = 0.00008); exercise time (p = 0.00003) were significantly reduced in univentricular patients. The heart rate at peak exercise was lower in the patients (p = 0.0003) and O(2)sat dropped significantly (p = 0.003).
  
  
  CONCLUSIONS
  The aerobic capacity, work and ventilatory parameters in Fontan patients are markedly reduced compared with controls. The anaerobic threshold was significantly lower. The decreased O(2)sat at peak exercise may suggest intrapulmonary shunting.
authors.affiliation: Department of Pediatric Cardiac Surgery, Polish-American Children's Hospital, Kraków, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Zajac
authors.forename: Lidia
authors.initials: L
authors.lastname: Tomkiewicz
authors.forename: Piotr
authors.initials: P
authors.lastname: Podolec
authors.forename: Wiesława
authors.initials: W
authors.lastname: Tracz
authors.forename: Edward
authors.initials: E
authors.lastname: Malec
mesh_terms: D000293:Adolescent; D015308:Anaerobic Threshold; D001794:Blood Pressure; D002648:Child; D002675:Child, Preschool; D005080:Exercise Test; D005260:Female; D018729:Fontan Procedure; D006321:Heart / Q000503:physiopathology*; D006330:Heart Defects, Congenital / Q000503:physiopathology* / Q000601:surgery; D006339:Heart Rate; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D010101:Oxygen Consumption; D012849:Sinoatrial Node / Q000503:physiopathology; D013147:Spirometry