Related Experiment Videos
Passive and active ventricular elastances of the left ventricle
Liang Zhong1, Dhanjoo N Ghista, Eddie Y K Ng
1College of Engineering, School of Mechanical and Production Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798. pg01538918@ntu.edu.sg
Biomedical Engineering Online
|February 15, 2005
Summary
This study introduces a novel concept of time-varying elastance to model the heart's pumping function. Active elastance (Ea) effectively measures left ventricular contractility, while passive elastance (Ep) quantifies resistance to filling.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
- Mathematical Modeling
Background:
- Traditional heart pump models rely on elastance and compliance.
- A new concept of time-varying passive and active elastance is presented.
- Elastance is defined by the relationship between ventricular pressure and volume (dP = EdV + VdE).
Purpose of the Study:
- To present the mathematical basis of time-varying ventricular elastance.
- To incorporate time-varying elastance into left ventricular (LV) models.
- To derive expressions for active elastance (Ea) and passive elastance (Ep).
Main Methods:
- Utilized patient catheterization-ventriculogram data.
- Computed passive and active elastance values.
- Developed LV models to simulate filling and systolic phases.
Main Results:
- Derived formulas for Ea and Ep.
- Ea correlates highly with traditional measures of LV contractility (Peak dP/dt, EF).
- Ep represents a volume-dependent stiffness, indicating resistance to filling.
Conclusions:
- Passive and active ventricular elastance can be calculated from single-beat P-V data using a simple LV model.
- Active elastance (Ea) characterizes ventricular contractile state.
- Passive elastance (Ep) measures resistance to ventricular filling.