Cardiorespiratory response to exercise in children after modified fontan operation.
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.
Zajac
Andrzej
A
Department of Pediatric Cardiac Surgery, Polish-American Children's Hospital, Kraków, Poland.
Tomkiewicz
Lidia
L
Podolec
Piotr
P
Tracz
Wiesława
W
Malec
Edward
E
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