Question of the Week
For March 21, 2017
A 45-year-old man presents to the emergency department with a 4-day history of progressive dyspnea. His wife reports that he has had intermittent fevers and lethargy for almost 3 weeks, starting several days after he had his first dental cleaning in several years. She states that he has no known cardiac disease but that he has a heart murmur from an infection he contracted as a child growing up in Honduras.
On examination, his temperature is 38.4°C, his heart rate is 110 beats per minute, and he is tachypneic. He has a low, rumbling diastolic murmur and a loud holosystolic murmur.
An electrocardiogram reveals sinus tachycardia without heart block. A transthoracic echocardiogram does not show a vegetation. Two blood culture bottles are positive for gram-positive cocci in chains.
Which one of the following next steps is most appropriate in this patient's evaluation?