|InterJournal Complex Systems, 1448
|Manuscript Number: |
Submission Date: 2004
|Models of Right Ventricular Shape and Function|
Abstract The right ventricle (RV) is an irregularly shaped organ with asynchronous motions during the systolic phase of its contraction. We have developed advanced modeling methods to assess RV shapes averaged through a population and applied our shape results to assess RV function in the presence of high pressures induced by pulmonary hypertension. In our model ‘s result of the RV shape, we observe a late systolic exponential decay of RV volume with time and hypothesize this decay as reflecting RV structural interaction with outflow resistance in a discharge modality - where the ventricle’s capacitance releases blood with a characteristic time constant proportional to flow resistance. To validate this capacitive and resistive model of RV contraction, we measure the pressure, outflow, and volume of piglets and calculate the pulmonary artery resistance R , volumetric capacitance C, and volumetric time constant T . Results: With seven piglets, regression fits of volume v(t) to an exponent yield a range from .940 <= r2<=.996 and measured time constants T are equal to the product of pulmonary resistance and ventricular capacitance T = 1.05*R x C + .03 , r2=.933. Conclusion: Volume is released from the right ventricle with a systolic time constant equal to the product of ventricular capacitance and pulmonary load resistance.
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