Objective The purpose of this study was to determine if delivery of epinephrine to heart via left atrial line is more efficient than right atrial epinephrine administration during cardiac resuscitation. Methods This randomized, blind, crossover controlled study, undertaken at an institute research laboratory, involved 6 mixed-breed dogs. Animals had two catheters placed into right atrium under anesthesia by ketamine, diazepam and relaxant with mechanical ventilation. Asphyxial cardiac arrest was induced by stopping ventilation, After 10 minutes of ventricular fibrillation, the dogs were randomized to two groups, each comprising 3 dogs. The dogs were given either left atrial or right atrial epinephrine (0.05mg/kg), and followed by 3 minutes cardiopulmonary resuscitation. 2 direct current countershocks(0.5J/kg) were attempted over one minute and, if unsuccessful, repeating resuscitative efforts were given by the same way. After two times cardiac resuscitation, if still unsuccessful, crossing over the left atrial and right atrial administration of epinephrine between two groups, and repeating the same resuscitation for another two times. Results In the first left atrial epinephrine group, return of spontaneous circulation was faster, and peak aterial pressure and peak heart rate were higher after epinephrine administration, and no animal needed subsequent epinephrine administration via right atrium. In the first right atrial epinephrine group, all the animals needed subsequent epinephrine administration via left atrium. Two animals restored spontaneous circulation and one didn`t response to epinephrine during four times resuscitations. Conclusion Administration of epinephrine via left atrium is more efficient than via right atrium for resuscitation of cardiac arrest.