Abstract: An atrial isolator comprising two tubular members, two lumens, drainage ports, and expandable occluders. The expandable occluders are adapted to engage an opening of the superior vena cava into the right atrium or the inferior vena cava and right tricuspid valve into the right atrium. The second tubular member is inserted into the lumen of the first tubular member to provide a displacement between the first expandable occluder and the second expandable occluder which is adjustable. A cardioplegia port is located between the two expandable occluders and in communication with a cardioplegic lumen. Methods of using such an atrial isolator are also disclosed, particularly to provide circulatory isolation of the heart and coronary blood vessels, and cardioplegia delivery.