Final answer:
In the context of constrictive pericarditis, the correct procedure to look for with an echo contrast study is the presystolic appearance of contrast in the IVC, which indicates compromised venous return.
Step-by-step explanation:
When a patient is sent to the echo lab with a diagnosis of constrictive pericarditis, a contrast study may be performed to look for specific abnormalities. The correct choice from the given options is d) Presystolic appearance of contrast in the IVC. This finding would be indicative of constrictive pericarditis, as it suggests that there is a compromised venous return to the heart during early ventricular diastole due to the increased rigidity of the pericardial sac. The presystolic phase refers to the time just before the contraction of the ventricles (ventricular systole).