An analytical approach to the determination of optimal phasing for external counterpulsation.

An inhomogeneous linear one-dimensional mathematical model is constructed as a conceptual approach to the study of the effects of External Counterpulsation (ECP) on the pressure and flow at the root of the aorta. The optimal operation of ECP is defined by two conditions: (1) minimization of the mean systolic pressure; and (b) maximization of the ratio of diastolic area over systolic area under the total pressure curve. The phase shift of the external pressure is determined so as to satisfy these two requirements.

Computer analysis of external counterpulsation by use of a nonlinear mathematical model of the cardiovascular system.

A pressure system externally applied to the limbs of a patient has been proven effective in assisting circulation in animal and clinical studies. In this study a nonlinear mathematical model of the cardiovascular system is utilized to determine the effectiveness of high-frequency components in the external pressure waveform. The development of the model, the method of analysis, and the results acquired with the model are presented in this report, demonstrating its suitability for the study of external counterpulsation.

The evolution of counterpulsation techniques.

Assisted circulation techniques are an outgrowth of extracorporeal pump oxygenator systems developed in the mid 1950s. But the differences in physiology of total perfusions and of parital perfusions for assisting circulation delayed the clinical application of the intra-aortic balloon. The problems and risks in providing circulation assistance and the approaches used to overcome them are discussed.