Ascending aorta synchronized pulsation (AASP) was found to be simple and effective method of counterpulsation directed at the root of the aorta. It provided excellent mechanical assistance for the treatment of severe cardiogenic shock following coronary artery ligation. Because the proximal site of counterpulsation requires low stroke pump volumes, only minimal hemolysis resulted. The AASP counterpulsation was performed for periods up to 90 minutes in ten dogs. After two minutes a significant increase in coronary flow and reduction in systolic pressures were observed, and after 90 minutes of continued AASP counterpulsation, pressures and flows increased from shock levels toward normotensive control levels and hemodynamic indices improved. These improvements persisted after AASP pumping was stopped in nine dogs, which proved AASP reversed the cardiogenic shock state.