The split-circulation assist device (SCAD) comprises an intra-aortic balloon pump (IABP), percutaneous cardiopulmonary support (PCPS) equipment, and two occlusion balloons that occlude the descending thoracic aorta by alternate inflation. With the SCAD, the failing heart, assisted by IABP, maintains only the upper 25-30% of the entire circulation without any interference by bypass flow from PCPS. An animal experiment indicated that a given rise in cardiac output caused an increase in aortic pressure in the SCAD group about three times greater than that in the control group (an ordinary combination of IABP and PCPS). Thus, by causing greater increases in arterial pressure, the SCAD may make possible detection of subtle increases in cardiac output, and therefore early detection of cardiac recovery. Multiple regression analysis from the pressure and flow data obtained in another experiment indicated that the SCAD facilitated the prediction of cardiac outputs and loads by preventing the bypass flow rate from influencing the aortic pressure. In addition, the SCAD may enhance cardiac assistance by increasing the effects of IABP. Therefore, the SCAD is a useful and potent new circulatory assist device that can facilitate both timely weaning from PCPS and heart failure management.