Exercise capacity of a contemporary cohort of children with hypoplastic left heart syndrome after staged palliation.
OBJECTIVE
Outcome of staged palliation for hypoplastic left heart syndrome has improved over the past decades. However, only little is known about the exercise capacity of children with palliated hypoplastic left heart syndrome where a systemic right ventricle supports the systemic circulation. The aim of the study was to assess exercise capacity in a contemporary cohort of children with hypoplastic left heart syndrome palliated in a single centre according to a uniform surgical strategy.


METHODS
Standardised cardiopulmonary exercise testing on a treadmill was performed in 46 consecutive hypoplastic left heart patients (median age: 6.0 (4.1-11.4) years). All but one patient reached the anaerobic threshold. Exercise data were compared to normal values obtained with a similar exercise protocol in a large cohort of paediatric volunteers.


RESULTS
Oxygen uptake at anaerobic threshold (26.9+/-6.0 ml kg(-1)min(-1); 74.5+/-18.2% of predicted) and maximal oxygen uptake (31.0+/-6.8 ml kg(-1)min(-1); 60.8+/-15.0% of predicted) were significantly reduced compared with controls (P<0.0001 for both). The limitation in exercise capacity was due to an impaired rise in heart rate (158+/-23 bpm; 79.7+/-11.5% of predicted; P<0.0001) and oxygen pulse (4.5+/-1.6 ml per beat; 85.5+/-22.0% of predicted; P<0.0001). Furthermore, respiration during exercise was inefficient with an elevated respiratory rate and reduced maximal tidal volume and minute ventilation at maximal exercise.


CONCLUSIONS
The exercise capacity of children with hypoplastic left heart syndrome is markedly reduced. Limitations in heart rate increase and stroke volume augmentation are the major contributors to this. An abnormal ventilatory response to exercise also adds to their limitation in exercise tolerance. However, the degree of physical disability does not justify discouraging these patients from school and leisure sports.
Möller
Peter
P
Department of Paediatric Cardiology, University Hospital of Schleswig-Holstein, Campus Kiel, Arnold-Heller-Strasse 3, Haus 9, 24105 Kiel, Germany. p.moeller@pedcard.uni-kiel.de
Weitz
Marcus
M
Jensen
Kai-Oliver
KO
Dubowy
Karl-Otto
KO
Furck
Anke K
AK
Scheewe
Jens
J
Kramer
Hans-Heiner
HH
Uebing
Anselm
A
D001794:Blood Pressure / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004562:Electrocardiography; D005080:Exercise Test / Q000379:methods; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D018636:Hypoplastic Left Heart Syndrome / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010166:Palliative Care / Q000379:methods; D015656:Respiratory Mechanics / Q000502:physiology; D016896:Treatment Outcome; D016526:Workload