The American Heart Association (AHA) has released evidence-based guidelines for the diagnosis, treatment, and follow-up care of patients with endocarditis. The updated recommendations, which were published in the June 14, 2005, issue of Circulation, reflect the evolving nature of the condition and new issues that physicians face when treating patients with infective endocarditis.

Diagnosis

Early diagnosis of endocarditis is important to initiate therapy and identify patients at high risk for complications. Although case definitions should not replace clinical judgment, physicians commonly use newly updated Duke criteria to diagnose suspected endocarditis.

Echocardiography should be performed immediately when endocarditis is suspected. Transesophageal echocardiography is preferred, but if clinical suspicion is low, or if transesophageal echocardiography is unavailable or shows abnormalities, transthoracic echocardiography is acceptable. If transthoracic echocardiography is positive or if worrisome clinical signs persist after a negative transthoracic echocardiography, physicians should follow-up with transesophageal echocardiography.

Treatment

Physicians should consider surgical therapy for patients with infective endocarditis and congestive heart failure. Other presentations that may require surgical intervention include fungal infective endocarditis, antibiotic-resistant infection, left-sided infective endocarditis caused by gramnegative bacteria, persistent infection after one week of antibiotic therapy, one or more embolic events in first two weeks of antimicrobial therapy, and certain echocardiographic findings. The decision to perform surgery should be based on the individual case, but surgery is most effective in the early phase of infective endocarditis.

Outpatient parenteral antibiotic therapy is safe, effective, and less expensive than inpatient therapy. Therefore, physicians should treat patients with intravenous antibiotics on an outpatient basis for at least two weeks if surgery is not indicated. Oral antibiotics are unreliable and not recommended for management of endocarditis. Out-patient therapy should be initiated only after the patient is evaluated and stabilized in the hospital. Rarely, low-risk patients may be treated entirely as outpatients. Effective outpatient care is dependent on a reliable in-home patient support system, easy access to the hospital, regular home nurse visits, and regular visits with a physician.

Follow-up

In most cases, infective endocarditis is resolved with appropriate treatment, but follow-up efforts are necessary.

Short-term follow-up should include:

• Transthoracic echocardiography

• Rehabilitation referral for patients who use illicit injection drugs

• Patient education on endocarditis

• Dental evaluation

• Removal of intravenous catheter at completion of therapy

• Blood cultures from three separate sites to identify febrile illness (before initiating antibiotic therapy)

• Physical examination to identify congestive heart failure

• Toxicity evaluation

Long-term follow-up should include:

• Echocardiography to evaluate valvular and ventricular function

• Continued dental evaluation

• Patient education on recurrence

• Ongoing observation