Infectious endocarditis Quiz: Ace Your Exams

A 45-year-old woman presents to the emergency department for evaluation of fever, hemoptysis, and shortness of breath. Past medical history is significant for a 20-pack smoking history and intravenous drug use. Temperature is 38.6°C (101.5°F), blood pressure is 98/69 mm Hg, pulse is 112/min, and respiratory rate is 28/min, and oxygen saturation is 90% on room air.  Physical examination is significant for scattered non-painful erythematous macules over the palms and soles, and a new grade 4/6 holosystolic murmur over the lower left sternal border radiating to the right lower sternal border. Lung auscultation is significant for decreased breath sounds at the lung base bilaterally. Laboratory evaluation shows a white blood cell count of 18,000/mm³ and a C-reactive protein of 50 mg/L. ECG shows sinus tachycardia. Chest CT scan with IV contrast is shown below. Blood cultures are sent and IV fluids are initiated with adequate blood pressure response. Which of the following is the best next step in management?
 
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