| Autor: |
Matonick, John, Li, John, Kedem, Joseph, Khaw, Kenneth |
| Zdroj: |
Cardiovascular Engineering: An International Journal; Mar2002, Vol. 2 Issue 1, p23-32, 10p |
| Abstrakt: |
How the left ventricle (LV) interacts with the arterial system (AS) has been a subject of considerable interest. Methods for analysis of their interaction have primarily been experimental. In recent years, model-based analyses have emerged including one that utilizes a time-varying elastance LV model coupled to a windkessel model of the arterial system. The ratio of the derived effective arterial elastance ( Eas) to the maximum elastance of the LV ( Emax) has been used extensively to describe the interaction but has its limitations. We developed an interactive model of the LV and AS that affords the analysis of the individual component variations on the overall dynamic interaction of the LV and AS. This model is used to investigate how vasoactive states can affect the interaction in terms of pressure–volume relations and energetics. Results show that with methoxamine (MTX) induced vasoconstriction the overall energy generated is greater than in nitroprusside (NTP) induced vasodilation, but the reverse is true in terms of kinetic power. Calculated cardiac efficiencies were generally lower than those found by other investigators, attributable to lower stroke volumes. The cardiac efficiency did not alter substantially during vasoactive conditions. This might be because the primary effect of MTX was in increasing peripheral resistance and a reflex induced decrease in heart rate prolonged the diastolic filling period, hence maintaining the stroke volume. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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