Maximal exercise capacity and oxygen consumption of lambs with an aortopulmonary left-to-right shunt
| Autor: | J. W. C. Gratama, W. G. Zijlstra, J. J. Meuzelaar, Jaap R. G. Kuipers, A. J. Werre, M Dalinghaus, J. H. Koers |
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| Rok vydání: | 1990 |
| Předmět: |
Aging
medicine.medical_specialty Physiology chemistry.chemical_element Hemodynamics Pulmonary Artery Oxygen Hemoglobins Oxygen Consumption Physical Conditioning Animal Physiology (medical) Internal medicine Heart rate medicine Left ventricular Stroke volume Animals Treadmill Aorta Sheep Body Weight Exercise capacity Surgery Shunt (medical) chemistry Cardiology Maximal exercise |
| Zdroj: | Journal of Applied Physiology. 69:1479-1485 |
| ISSN: | 1522-1601 8750-7587 |
| Popis: | We determined maximal exercise capacity and measured hemodynamics in 10 6-wk-old lambs with an aortopulmonary left-to-right shunt [S, 57 +/- 11%, (SD)] and in 9 control lambs (C) during a graded treadmill test 8 days after surgery. Maximal exercise capacity (3.7 +/- 0.2 km/h and 10 +/- 5% inclination vs. 4.0 +/- 0.9 km/h and 15 +/- 0% inclination, P less than 0.02) and peak oxygen consumption (25 +/- 7 vs. 34 +/- 8 ml O2.min-1.kg-1, P less than 0.02) were both lower in the shunt than in the control lambs. This was due to a lower maximal systemic blood flow in the shunt lambs (271 +/- 38 vs. 359 +/- 71 ml.min-1.kg-1, P less than 0.01). Despite their high maximal left ventricular output, which was higher than in the control lambs (448 +/- 87 vs. 359 +/- 71 ml.min-1.kg-1, P less than 0.05), the left-to-right shunt could not be compensated for during maximal exercise because of a decreased reserve in heart rate (S: 183 +/- 22 to 277 +/- 38 beats/min; C: 136 +/- 25 to 287 +/- 29 beats/min) and in left ventricular stroke volume (S: 1.8 +/- 0.3 to 1.6 +/- 0.4 ml/kg; C: 1.0 +/- 0.3 to 1.3 +/- 0.2 ml/kg). We conclude that exercise capacity of shunt lambs is lower than that of control lambs, despite a good left ventricular performance, because a part of the reserves for increasing the left ventricular output is already utilized at rest. |
| Databáze: | OpenAIRE |
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