Because of the controversy concerning techniques of cardiac resuscitation, it was decided to return to the laboratory to evaluate the hemodynamic benefits of these techniques under more controlled conditions. The experimental design revealed closed-chest massage to be an effective technique when compared to open-chest resuscitation. Closed-chest massage is proposed as a scientifically valid interim resuscitative measure which, if applied within the crucial four-minute limit, will maintain life until definitive diagnostic and therapeutic procedures can be instituted.