A Servomechanism to Drive an Artificial Heart Inside the Chest

Kw, Hiller; Seidel, W; Wj, Kolff

doi:10.1097/00002480-196204000-00029

Cited by 32 publications

(10 citation statements)

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“…A variety of TAH control methods have been evaluated in various laboratories [13,14]. Many investigators have used a control algorithm based on Starling's law and others have proposed a control method in which AoP is maintained as a constant value [15].…”

Section: Future Prediction By An Autonomic Nerve and Hemodynamicsmentioning

confidence: 99%

“…A control algorithm for the TAH has been discussed more and more from various viewpoints [13][14][15]. Several investigators have proposed an automatic TAH control algorithm to prevent thrombus formation and suggested the importance of full stroke driving [14,15].…”

Section: Mayer Wave Control For An Artificial Heartmentioning

confidence: 99%

“…Several investigators have proposed an automatic TAH control algorithm to prevent thrombus formation and suggested the importance of full stroke driving [14,15]. Some researchers reported the importance of left and right heart balance, and some investigators have controlled their artificial hearts according to Starling's law [14]. Other researchers have controlled their devices to maintain arterial blood pressures [15].…”

Section: Mayer Wave Control For An Artificial Heartmentioning

confidence: 99%

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Searching for the Origin of Chaos

Yambe¹,

Yoshizawa²,

Tabayashi³

et al. 2009

Nonlinear Biomedical Signal Processing, Dynamic Analysis and Modeling

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The clinical significance of chaotic dynamics in the cardiovascular system has attracted attention. The circulatory system is a kind of complex system having many feedback circuits, so it has been difficult to investigate the origin of chaos in the circulatory system. In this study, we investigated the origin of chaos by using the methodology of open-loop analysis with an artificial heart, which did not have any fluctuation in its own pumping rate and contraction power, in chronic animal experiments using healthy adult goats. In the circulatory time series data of the artificial heart, which did not have any fluctuation, low-dimensional deterministic chaos was discovered by nonlinear mathematical analysis, suggesting the importance of the blood vessel system in the chaotic dynamics of the cardiovascular system. To investigate the origin of chaos further, sympathetic nerve activity was directly measured in the animal experiments with artificial heart circulation. Chaotic dynamics was also recognized in the sympathetic nerve action potentials, even during artificial heart circulation, suggesting the importance of a central nervous system. In the next step, in order to generate chaotic dynamics in the circulation, an electrical simulation model of left heart circulation with a feedback loop with some delay was tested, and we found that we can make chaos in the circulation by a feedback loop. Thus, we constituted an artificial baroreflex system with an artificial heart system and found that we could introduce chaos in an animal model. Finally, we proposed clinical application of these methodologies for the diagnosis of an autonomic nervous system and found that it may be useful. These findings may be useful for analyzing the nonlinear dynamics in the circulation.

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Section: Future Prediction By An Autonomic Nerve and Hemodynamicsmentioning

confidence: 99%

Section: Mayer Wave Control For An Artificial Heartmentioning

confidence: 99%

Section: Mayer Wave Control For An Artificial Heartmentioning

confidence: 99%

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Searching for the Origin of Chaos

Yambe¹,

Yoshizawa²,

Tabayashi³

et al. 2009

Nonlinear Biomedical Signal Processing, Dynamic Analysis and Modeling

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show abstract

“…Early TAH researchers had tried to provide Starling's law characteristics to the blood pump so that cardiac output changed responding to venous return passively [1][2][3][4][5]. However, it was not so easy to control venous pressure [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Concept of left atrial pressure estimation using its pulsatile amplitude in the helical flow total artificial heart

Saito

Igarashi

et al. 2014

J Artif Organs

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The total artificial heart (TAH) requires physiological control to respond to the metabolic demand of the body. To date, 1/R control is a single physiological control method that can control venous pressure. To realize an implantable 1/R control system, we are developing a new pressure measuring method using absolute pressure sensor. To find a method for absolute pressure sensor, which went well without calibration, concept of left atrial pressure (LAP) estimation using its pulsatile amplitude was proposed. Its possibility was investigated with two long-term survived goats whose hearts were replaced with the helical flow TAHs. In manual control condition, there existed a positive relation between mean LAP (mLAP) and normalized pulsatile amplitude (NPA). Percent systole revealed not to affect the relationship between mLAP and NPA. Dispersion was observed between different pulse rates. As for cardiac output difference (QLD) that is the difference of flow rate between systolic and diastolic phases, similar results were obtained except in low QLDs. In the 1/R control condition, relatively high correlation between mLAP and NPA could be obtained. In estimation of mLAP using the correlating function of individual goat, fairly good correlation was obtained between measured mLAP and estimated mLAP. Despite that further studies are necessary, it was demonstrated that the concept of the LAP estimation could be possible.

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“…Various control methods for an artificial heart have been attempted worldwide (1)(2)(3)(4)(5). First, we must achieve automatic control for the artificial heart itself (2).…”

mentioning

confidence: 99%

A Future Prediction Type Artificial Heart System

Yambe

Tanizuka²,

Yoshizawa

et al. 1999

Artificial Organs

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The demand of the biological system needs to be predicted to consider the quality of life (QOL) of a patient with an artificial heart system. The purpose of this study was the prediction of the imminent cardiac output and the predictive control for an artificial heart. For that purpose, autonomic nerve information was applied in this study. Nervous sympathicus action potentials were measured, and a prediction function of cardiac output was made using the sympathetic tone and preload and after-load measurement with multiple regression analysis. The predicted value showed significant correlation with the measured value after 2.9 s. Currently, however, long-term instrumentation of the nervous sympathicus potential is difficult. Thus, hemodynamic fluctuations, which recently have attracted attention, were used in this study. A prediction function using the Mayer wave, which represented nervous sympathicus, was determined. As a result, mid-term prediction became possible. Furthermore, a measurement of the vagal nerve was used as a possible long-term prediction parameter. For long-term prediction, Hurst exponent analysis was used in this study. Vagal nerve discharges in the changing position showed alteration of long-term determination. In conclusion, the future prediction control of an artificial heart takes shape using these prediction functions.

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A Servomechanism to Drive an Artificial Heart Inside the Chest

Cited by 32 publications

References 0 publications

Searching for the Origin of Chaos

Searching for the Origin of Chaos

Concept of left atrial pressure estimation using its pulsatile amplitude in the helical flow total artificial heart

A Future Prediction Type Artificial Heart System

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