A patient who recently had a pacemaker implanted at your hospital presents with chest pain and shortness of breath, and the vital signs are 101.5°F body temperature and 125/85 mm Hg blood pressure. The echocardiogram of the client shows valve perforation and valvular vegetations, and a new regurgitant murmur is heard on auscultation. Blood cultures are positive and growing gram-positive cocci. Which condition has the patient developed?

A. Infective endocarditis
B. Angina
C. Myocarditis
D. Pericarditis