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Mechanical circulatory support is an essential issue in the management of patients with end-stage cardiac failure. The aim of this study is to evaluate the efficacy of temporary support with a centrifugal blood pump as bridge to heart function recovery or bridge to transplantation.Heart recovery is achieved by improving ventricular mechanical working conditions with proper modifications of preload and afterload.This article assesses the advantages of a novel “cardiac chambers” cannulation setting versus the traditional one, in the case of biventricular or isolated right ventricular failure. The study was conducted using a numerical computer model based on the work by Guyton, Sagawa, Westerhof, and Noordergraaf. Simulation of the planned trials was achieved by changing the model parameters, the pump angular velocity, and the inflow and outflow settings. (Int J Artif Organs 2007; 30: 604–10)

A mechanical filter developed to improve the performances of an artificial heart whose electrical motor has a reciprocating motion is presented. The filter phases the mechanical load strongly reducing its inertial component (which is of the same order of magnitude as the useful load). The analysis reported for a prototype developed by us shows that when its rate is equal to the first resonant frequency of the filter, a reduction of about 50 percent for the maximum value of the torque due to inertial and friction forces is obtained.

A mechanical filter developed to improve the performances of an artificial heart whose electrical motor has a reciprocating motion is presented. The filter phases the mechanical load strongly reducing its inertial component (which is of the same order of magnitude as the useful load). The analysis reported for a prototype developed by us shows that when its rate is equal to the first resonant frequency of the filter, a reduction of about 50 percent for the maximum value of the torque due to inertial and friction forces is obtained.

A new test circulatory system (TCS) has been developed for thein vitrotesting of artificial hearts (AH) and for research in cardiovascular engineering, when connected to an AH that mimics the natural heart. The TCS is controlled by five variables whereby the slopes of the systemic and pulmonary venous return curves and the mean circulatory pressure can be fixed. It allows us to observe the mutual influence between TCS and AH characteristics and particularly the blood volume distribution, the pressure distribution, and the flowrates in steady-state conditions and (in the near future) also in dynamic conditions. A steady-state mathematical analysis describing the TCS is reported. Numerical results for the human circulatory system at different levels of activity and in physiologic conditions are shown. A first prototype of the TCS has been working for more than one year. The experimental results are in agreement with the mathematical analysis.

Abstract: This work deals with a method of determining the acceptable ranges of the weights in a threshold element, and evaluating the optimum set of a class of symmetric linearly separable functions. This set maximizes the correct operation probability of ann-input threshold element in presence of noise.

Abstract: The performance of ann-input linear threshold element in presence of noise is characterized, in this work, by the probability of correct operationP T . A method is shown for the determination ofP T as a function of the characteristics of the noise, the parameters of the threshold element and the probabilities of occurrence of the various input patterns.