Down syndrome and cardiac response after exercise

http://www.ncbi.nlm.nih.gov/pubmed/22331518

Neth Heart J. 2012 Feb 14. [Epub ahead of print]
Adults with Down syndrome have reduced cardiac response after light exercise testing.
Vis JC, De Bruin-Bon HA, Bouma BJ, Huisman SA, Imschoot L, van den Brink K, Mulder BJ.
Source
Department of Cardiology, Academic Medical Centre, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands.

Abstract
OBJECTIVE:
Physical fitness is reduced in adults with Down syndrome (DS). The present study was conducted to elucidate the exercise response in adults with DS.

DESIGN:
Case controlled before-after trial.

SETTING:
Residential centre for people with intellectual disabilities.

PARTICIPANTS:
96 Adults with DS, 25 non-DS adults with an intellectual disability, 33 controls.

INTERVENTIONS:
Echocardiography to exclude heart defects and to measure cardiac index (CI) in the supine position, supine position with raised legs, and following ten knee bends.

MAIN OUTCOME MEASURE:
Exercise testing

RESULTS:
At rest, mean CI was not significantly different between persons with DS and controls (2.3 vs. 2.4 l/min/m(2), p = 0.3). However, mean CI after exercise was significantly lower in DS (2.9 vs. 3.7 l/min/m(2), p < 0.001) and mean CI increase from rest to exercise was more than 50% lower in DS. On the contrary, CI after exercise was similar among controls and non-DS adults with an intellectual disability. Significantly lower stroke volumes in DS were found with insufficient heart rate response.

CONCLUSIONS:
CI at rest was similar in adults with DS and controls; however persons with DS have a diminished cardiac response to exercise. Stroke volumes were significantly lower in DS during exercise and a compensated heightened heart rate was absent.