Conventional non-invasive mechanical circulatory assist methods such as intra-aortic balloon pumping are of little effectiveness in cases of severe ventricular failure. The proposed study is concerned with the development and testing, on a mock circulatory loop and in a series of dog experiments, of an automated combined assist system for the profound support of the failing heart. This system is mildly invasive and consists of the synergistic use of intra-aortic balloon pumping and partial veno-arterial bypass. Previous in vivo studies using this system with no automation have shown that it is quite effective in achieving its clinical objectives, and our purpose is to investigate the ability of the control systems developed herein to match the optimal manual setting of the assist system. The end result of the project is a portable compact automatically controlled ventricular assist system that can be rapidly and easily instituted, thus improving the chance of survival and recovery of acute myocardial infarction and cardiogenic shock victims.