A dual lumen cannula includes a first lumen having at least one aperture for removing a fluid from the interior of the heart right atrium, and a second lumen for delivering a fluid into the interior of the pulmonary artery or the heart left atrium. The second lumen includes a distal selectively curvable portion having a length of from about 4 cm to about 22 cm to position an end thereof within the interior of the pulmonary artery lumen or the human heart left atrium interior when a distal end of the first lumen is positioned within a right atrium of the human heart. The second lumen may also include a distal anchoring structure for preventing inadvertent withdrawal from a surgical site.