| Autor: |
WYNS, W., MELIN, J. A., VANBUTSELE, R. J., DE COSTER, P. M., STEELS, M., PIRET, L., DETRY, J.-M. R. |
| Zdroj: |
European Heart Journal; Nov1982, Vol. 3 Issue 6, p529-536, 8p |
| Abstrakt: |
Ventricular volumes were measured in 10 normal subjects by using two independent methods: the stroke volume was obtained by the Fick principle and the ejection fraction by multigated radionuclide angiography. Data were collected at rest in the supine and upright positions and during an upright exercise test, which included three levels of increasing severity. The left and right ventricular end-diastolic volumes (EDV) were maximal in the supine posture (respectively 183 and 260 ml); at rest both were significantly lower in the upright position (158 and 220 ml). At maximal exercise, the ventricular end-diastolic volumes were similar (left EDV=147 ml) or slightly lower (right EDV= 178 ml) than at rest in the upright position. During upright exercise, the end-systolic volumes (ESV) gradually decreased (<0.001) from 56 to 34 ml (left ESV) and from 118 to 64 ml (right ESV); simultaneously, the left ventricular ejection fraction (EF) increased from 64 to 77% (<0.001) and the right ventricular EF increased from 47 to 64% (<0.001). Since during exercise in the upright position, the end-diastolic volumes are unchanged or tend to decrease, a Frank-Starling mechanism cannot be called upon; the cardiac response to upright exercise is thus mainly based on an increased venous return and on an increase in myocardial contractility reflected by the increase in ejection fraction and the decrease in end-systolic volumes. The methods used in the present study can provide reference values for the measurement of absolute ventricular volumes during exercise by gated equilibrium radionuclide angiography. [ABSTRACT FROM PUBLISHER] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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