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Chaotic dynamics in circulation with Tohoku University vibrating flow pump
S Nitta1, T Yambe, S Kobayashi
1Department of Medical Engineering and Cardiology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan. nitta@idac.tohoku.ac.jp
Artificial Organs
|February 9, 1999
Summary
This study shows that oscillating blood flow from a vibrating flow pump (VFP) in left ventricular assist devices (LVADs) can reduce vascular resistance and improve circulatory dynamics by altering nonlinear cardiovascular patterns.
Area of Science:
- Biomedical Engineering
- Cardiovascular Physiology
- Nonlinear Dynamics
Background:
- Ventricular assist systems (VAS) are crucial for managing heart failure.
- A novel vibrating flow pump (VFP) generates high-frequency oscillated blood flow.
- Evaluating circulatory regulation requires a systems-level, nonlinear approach.
Purpose of the Study:
- To analyze the effects of left ventricular assistance using oscillated blood flow from a VFP.
- To assess the impact on the entire circulatory regulatory system using nonlinear mathematics.
- To determine the potential for optimizing VAS control through nonlinear dynamic analysis.
Main Methods:
- Chronic animal experiments (goats) with VFP left heart bypass (left atrium to descending aorta).
- Recording of ECG, arterial blood pressure, and blood flow (VFP and descending aorta).
- Application of nonlinear mathematical techniques: phase space embedding, Lyapunov method, fractal dimension, and power spectrum analysis.
Main Results:
- VFP-assisted left ventricular bypass significantly decreased Mayer wave fluctuations in the power spectrum.
- A significant reduction in the fractal dimension of hemodynamics was observed.
- Peripheral vascular resistance was significantly decreased during VFP assistance.
Conclusions:
- Oscillated blood flow from VFP impacts nonlinear dynamics governing cardiovascular regulation.
- Decreased Mayer wave power and fractal dimension suggest reduced sympathetic activity and altered hemodynamic attractors.
- Nonlinear dynamic analysis offers a valuable tool for designing optimal VAS control strategies.