Antimicrobial prophylaxis for prevention of bacterial endocarditis is recommended in patients with which of the following?

• A. Implanted pacemakers
• B. Atrial septal defect
• C. Previous coronary artery bypass grafts
• D. Mitral valve prolapse with regurgitation

Answer: (D)

Endocarditis prophylaxis targets people with heart conditions that create surfaces where bacteria can more easily adhere after bacteremia from a procedure. Mitral valve prolapse with regurgitation fits this scenario because the regurgitant jet and abnormal valve surface provide a nidus for bacteria to settle if bacteria enter the bloodstream during procedures that disrupt oral or other mucosa. Giving a dose of antibiotics before such procedures helps reduce the chance that bacteria colonize the valve.

The other choices don’t carry the same prophylaxis indication. An implanted pacemaker by itself isn’t a standard reason to prescribe antibiotics for endocarditis prevention. An atrial septal defect without additional high-risk features isn’t considered an indication, and prior coronary artery bypass grafts don’t place the endocardium at the same risk level as the lesions that warrant prophylaxis.

So, mitral valve prolapse with regurgitation is the scenario where prophylaxis is recommended.