Determinants of left ventricular preload-adjusted maximal power
| Autor: | P. Benoit, H. Alex Leather, Philippe Kolh, Alexandre Ghuysen, Bernard Lambermont, Philippe Morimont, Patrick Segers, Vincent Tchana-Sato, Patrick Wouters, Pascal Verdonck, Jean-Michel Dogné |
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| Rok vydání: | 2003 |
| Předmět: |
Male
medicine.medical_specialty Swine Physiology Left Hemodynamics Blood Pressure Ventricular Function Left Heart Rate Ventricule gauche Physiology (medical) Internal medicine medicine Ventricular Function Animals Cardiac Output Ventricular function business.industry Stroke Volume Hypertrophy Arteries Blood flow Myocardial Contraction Left Ventricular Elasticity Power (physics) Surgery Preload Blood pressure Circulatory system Cardiology Female Hypertrophy Left Ventricular Vascular Resistance Energy Metabolism Cardiology and Cardiovascular Medicine business |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 284:H2295-H2301 |
| ISSN: | 1522-1539 0363-6135 |
| DOI: | 10.1152/ajpheart.01110.2002 |
| Popis: | Maximal left ventricular (LV) hydraulic power output (PWRmax), corrected for preload as PWRmax/(Ved)β (where Ved is the end-diastolic volume and β is a constant coefficient), is an index of LV contractility. Whereas preload-adjusted maximal power (PAMP) is usually calculated with β = 2, there is uncertainty about the optimal value of β (β = 1 for the normal LV and 2 for the dilated LV). The aim of this work is to study the determining factors of β. The data set consisted of 245 recordings (steady state and vena cava occlusion) in 10 animals in an ischemic heart pig model. The occlusion data yielded the slope ( E es; 2.01 ± 0.77 mmHg/ml, range 0.71–4.16 mmHg/ml) and intercept (V0; −11.9 ± 22.6 ml; range −76 to 39 ml) of the end-systolic pressure-volume relation, and the optimal β-factor (assessed by fitting an exponential curve through the Ved-PWRmax relation) was 1.94 ± 0.88 (range 0.29–4.73). The relation of β with Ved was weak [β = 0.60 + 0.02(Ved); r 2 = 0.20]. In contrast, we found an excellent exponential relation between V0 and β [β = 2.16[Formula: see text] r 2 = 0.70]. PAMP, calculated from the steady-state data, was 0.64 ± 0.40 mW/ml2 (range 0.14–2.83 mW/ml2) with a poor correlation with E es ( r = 0.30, P< 0.001). An alternative formulation of PAMP as PWRmax/(Ved − V0)2, incorporating V0, yielded 0.47 ± 0.26 mW/ml2 (range 0.09–1.42 mW/ml2) and was highly correlated with E es ( r = 0.89, P< 0.001). In conclusion, correct preload adjustment of maximal LV power requires incorporation of V0 and thus of data measured under altered loading conditions. |
| Databáze: | OpenAIRE |
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