This proposal describes a new and highly effective type of cardiopulmonary resuscitation (CPR) and requests support for hemodynamic studies in animals necessary to pave the way toward early clinical trials. The new technique involves all the steps of present CPR with the simple addition of abdominal compressions, interposed between chest compressions. That is, the abdomen is compressed only during the release phase of chest compression. In preliminary studies we have found this new technique, named IAC-CPR for interposed abdominal compression, to improve artificial cardiac output during ventricular fibrillation 2 to 3-fold compared to standard CPR. Blood pressures during IAC-CPR have were 30-150 systolic/20-50 diastolic. The technique is a potential improvement in Basic Life Support, easily performed under field conditions by 2 or 3 rescuers with no equipment other than their bare hands. The principal investigator, who has been awarded an RCDA to study CPR hemodynamics, seeks support for statistically significant animal studies of cardiac output, carotid artery blood flow, and regional blood flow to vital organs during ventricular fibrillation with IAC-CPR as compared to standard CPR. In addition funds are sought to optimize the site, force, area, and timing of interposed abdominal compression in animals and to investigate hypotheses concerning the mechanism of flow enhancement.