A man with prosthetic heart valve underwent hemicolectomy and after some days complains of left hypochondriac pain, fever and has a systolic murmur. What is the next investigation to ascertain the cause of HF?

The key is B. Blood culture. [The diagnosis is infective endocarditis. Fever + new murmur suggest

endocarditis until proven otherwise. Important risk factors: dermatitis, IV injections, renal failure, organ

transplantation, DM, post operative wound. Risk factors for abnormal valves: aortic or mitral valve

disease, tricuspid valve in IV drug users, prosthetic valves].