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Crossbridge model compatible with the linear relation between left ventricular oxygen consumption and pressure-volume
1Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, Osaka, Japan.
Japanese Heart Journal
|May 1, 1988
Summary
Ventricular pressure-volume area (PVA) linearly correlates with ventricular oxygen consumption (Vo2). A new crossbridge model explains this relationship through the energy balance of ATP hydrolysis during heart contractions.
Area of Science:
- Cardiovascular Physiology
- Biophysics
- Computational Biology
Background:
- Ventricular pressure-volume area (PVA) quantifies mechanical energy per heartbeat.
- PVA correlates linearly with ventricular oxygen consumption (Vo2) in animal models.
- The stoichiometry between Vo2 and PVA is constant across varying contractile states.
Purpose of the Study:
- To theoretically link PVA to ATP hydrolysis using a novel crossbridge (CB) model.
- To investigate the underlying mechanisms of the empirical Vo2-PVA relationship.
- To understand the chemomechanical energy transduction in cardiac contraction.
Main Methods:
- Development of a new crossbridge (CB) model.
- Theoretical analysis relating PVA to enthalpy changes from ATP hydrolysis.
- Utilizing a time-varying elasticity model to simulate pressure-volume relations.
Main Results:
- The CB model theoretically relates PVA to the total enthalpy change of ATP hydrolysis.
- The analysis supports the empirical linear Vo2-PVA relationship.
- The findings attribute the Vo2-PVA relation to energy balance in CB cycles.
Conclusions:
- The study provides a theoretical framework for the Vo2-PVA relationship.
- Energy balance in crossbridge cycles underlies cardiac oxygen consumption.
- This work advances understanding of myocardial energy metabolism and mechanics.