Infective endocarditis is an infection of the endocardial surface of the heart, most often involving the heart valves, in which microorganisms colonize the tissue and form vegetations. These vegetations are friable clumps of fibrin, platelets, and microbes. The clinical importance for the nurse rests on two linked ideas. First, diagnosis depends on identifying the causative organism, which is why drawing blood cultures before starting antibiotics is a defining nursing priority; giving an antibiotic first can sterilize the sample and prevent the team from ever isolating the pathogen or selecting targeted therapy. Second, the vegetations can break loose and travel as septic emboli, scattering infection and clot to the brain, lungs, spleen, kidneys, or extremities. On the NCLEX-RN, this topic tests the nurse's grasp of correct culture sequencing, recognition of embolic and heart-failure complications, and prioritization of timely, accurate assessment.