The patient should undergo aortic valve replacement now. Although he is hemodynamically stable and does not require pacemaker support, the presence of a new conduction defect confirms extension of the infection into the perivalvular tissues as suggested by echocardiography. When this occurs, the effectiveness of cure with antibiotics alone is decreased significantly, and early surgical intervention is indicated. Other indications for early surgery in native valve infective endocarditis include valve stenosis or regurgitation resulting in heart failure; left-sided endocarditis caused by Staphylococcus aureus, fungal, or other highly resistant organisms; endocarditis complicated by annular or aortic abscess; and endocarditis with persistent bacteremia or fever lasting longer than 5 to 7 days after starting antibiotic therapy. Additionally, early surgery is reasonable in patients with infective endocarditis who have recurrent emboli and persistent vegetations on antibiotic therapy, and may be considered in patients with native valve endocarditis who have mobile vegetations greater than 10 mm in length.

Duration of antibiotic therapy in patients with native valve infective endocarditis is generally 4 to 6 weeks, based upon the specific organism, the site of infection, and any associated complications. Generally, 6-week treatment regimens are used in patients with more virulent or highly resistant organisms and those with cardiac or extracardiac infectious complications. Prolonged treatment for 3 months as therapy for this patient would not be appropriate, even with surgical intervention, and would not be indicated in other patients with native valve endocarditis except in certain situations.

Delaying intervention for 6 weeks of antibiotic therapy or treating with antibiotics alone without surgery would not likely adequately address this patient's endocarditis-related complications. In addition, this approach may result in further decompensation of the patient's clinical status and an increased operative risk for intervention at a later time.

Key to management of patients with infective endocarditis requiring surgery is a multidisciplinary approach involving the internist, cardiologist, infectious disease specialist, and cardiac surgeon.