Nonlinear Mathematical Analysis of the Hemodynamic Parameters During Left Ventricular Assistance with Oscillated Blood Flow

Yambe, Tomoyuki; Kobayashi, Shin; Sonobe, Taro; Naganuma, S.; Nanka, S.; Hashimoto, Hiroyuki; Yoshizawa, Makoto; Tabayashi, K.; Takayasu, Hideki; Takeda, Hiroshi; Nitta, Shin Ichi

doi:10.1111/j.1525-1594.1997.tb03711.x

Cited by 5 publications

(7 citation statements)

References 20 publications

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“…The unique flow pattern of the VFP has many unique characteristics as we have shown (5)(6)(7)(8)(9)(10). These characteristics may be deduced if we consider the pulmonary vessels.…”

Section: Discussionmentioning

confidence: 87%

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Control of the Pulmonary Arterial Resistance by the Use of the Oscillated Assist Flow

et al. 1998

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In the clinical application of supporting circulation, the treatment of a patient with pulmonary hypertension is very important. We developed the electromagnetically driven vibrating flow pump (VFP) as a totally implantable type ventricular assist system. The artificial heart driven by electromagnetic forces creates high speed oscillation flow around 10-50 Hz. Assistance by high-speed oscillation flow has an interesting influence on the cardiovascular system. In this study, we carried out research on the influence such oscillation flow had on the pulmonary arterial vessels, and the supporting flow wave-form that controlled pulmonary vascular resistance was considered. Six healthy adult goats of both sexes were used in the experiments. We carried out inhalation anesthesia and performed intubation. The thorax was opened through left fourth rib resection. Right heart bypass was performed from the right atrium to the pulmonary artery. The flow of right heart assistance was maintained within 20-25% of total flow. Our purpose was to add flow of a specific high frequency to the right heart circulation. The hemodynamic parameters were recorded on a magnetic tape data recorder and input into a computer through an A-D converter. A result identified was that the pulmonary vascular resistance changed according to the alteration of the driving frequency of the VFP even during the same flow assistance. The resistance of the pulmonary arterial vessels became smaller when the driving of the VFP of 30 Hz was added to the right heart circulation. This was significant even when compared with continuous flow right heart assist. The characteristics of impedance appeared to have interesting alterations as well. Control of pulmonary vascular resistance by right heart assistance becomes possible if these results are applied. Accordingly, it may become one of the choices for treatment of a patient with pulmonary hypertension.

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“…The unique flow pattern of the VFP has many unique characteristics as we have shown (5)(6)(7)(8)(9)(10). These characteristics may be deduced if we consider the pulmonary vessels.…”

Section: Discussionmentioning

confidence: 87%

“…In Tohoku University, we have been developing a totally implantable artificial heart system with a new driving principle (5–9). It is a new mechanical heart having a blood flow waveform of high frequency (6,7).…”

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confidence: 99%

Control of the Pulmonary Arterial Resistance by the Use of the Oscillated Assist Flow

et al. 1998

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“…Thus, when the Mayer wave falls, one part in period fluctuation is lacking. When one period fluctuation is lacking, one part of 1/f fluctuation is lacking ( 21). When 1/f fluctuation is broken, it may be that the fractal dimension falls.…”

Section: Discussionmentioning

confidence: 99%

“…When 1/f fluctuation is broken, it may be that the fractal dimension falls. The chaos and fractal of the time series data were thought to be related to the 1/f fluctuations ( 16–21). This nonlinearity may be related to the circulatory regulatory systems, including the neural and hormonal control systems ( 18–21).…”

Section: Discussionmentioning

confidence: 99%

Chaotic Dynamics in Circulation with Tohoku University Vibrating Flow Pump

et al. 1999

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For the development of a totally implantable ventricular assist system (VAS), we have been developing the vibrating flow pump (VFP), which can generate oscillated blood flow with a relative high frequency (10-50 Hz) for a totally implantable system. In this study, the effects of left ventricular assistance with this unique oscillated blood flow were analyzed by the use of nonlinear mathematics for evaluation as the whole circulatory regulatory system, not as the decomposed parts of the system. Left heart bypasses using the VFP from the left atrium to the descending aorta were performed in chronic animal experiments using healthy adult goats. The ECG, arterial blood pressure, VFP pump flow, and the flow of the descending aorta were recorded in the data recorder during awake conditions and analyzed in a personal computer system through an A-D convertor. By the use of nonlinear mathematics, time series data were embedded into the phase space, the Lyapunov numerical method, fractal dimension analysis, and power spectrum analysis were performed to evaluate nonlinear dynamics. During left ventricular assistance with the VFP, Mayer wave fluctuations were decreased in the power spectrum, the fractal dimension of the hemodynamics was significantly decreased, and peripheral vascular resistance was significantly decreased. These results suggest that nonlinear dynamics, which mediate the cardiovascular dynamics, may be affected during left ventricular (LV) bypass with oscillated flow. The decreased power of the Mayer wave in the spectrum caused the limit cycle attractor of the hemodynamics and decreased peripheral resistance. Decreased sympathetic discharges may be the origin of the decreased Mayer wave and fractal dimension. These nonlinear dynamic analyses may be useful to design optimal VAS control.

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“…Recently, the quality of life supported by an artificial heart system has been debated. Accordingly, it has become important to develop a totally implantable artificial heart system (1)(2)(3)(4). Artificial hearts of various kinds have been developed all over the world (1)(2)(3).…”

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Left Heart Bypass Using the Oscillated Blood Flow with Totally Implantable Vibrating Flow Pump

et al. 1998

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Aiming at a totally implantable ventricular assist device (VAD), a vibrating flow pump (VFP) was developed in Tohoku University. A transcutaneous energy transmission system (TETS) using an amorphous fiber was developed for the totally implantable VAD system. The VFP works with a higher frequency than the natural heart of a biological system, a frequency of 10-50 Hz. In this research, animal experiments on left heart bypass were performed with healthy goats. Blood from the apex of the left ventricle was received and was sent to the aorta so that an adequate supporting effect of the left heart was provided. In particular, the depression effect of the left ventricle was obvious. As a result, sufficient artificial heart flow was provided. For a totally implantable type VAD, left heart bypass of almost 100% may become necessary in some situations. Therefore, apex approaches of left heart bypass may be desirable. From an anatomical consideration, an apex of the heart is suitable for the VFP of this totally implantable type. In the left heart bypass for which the apex of the heart was used, an almost 100% bypass was possible. This is a requirement that is important when waiting for recovery of sufficient cardiac function. It is also important that left heart circulation is maintained fully by an artificial heart of the complete implantation type. The VFP was considered to be useful as a totally implantable type artificial heart from the results.

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Nonlinear Mathematical Analysis of the Hemodynamic Parameters During Left Ventricular Assistance with Oscillated Blood Flow

Cited by 5 publications

References 20 publications

Control of the Pulmonary Arterial Resistance by the Use of the Oscillated Assist Flow

Control of the Pulmonary Arterial Resistance by the Use of the Oscillated Assist Flow

Chaotic Dynamics in Circulation with Tohoku University Vibrating Flow Pump

Left Heart Bypass Using the Oscillated Blood Flow with Totally Implantable Vibrating Flow Pump

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