A 40-year-old man with a history of intravenous drug abuse develops rapidly progressive right-sided hea failure. These symptoms are most likely due to which of the following conditions?

Tricuspid insufficiency secondary to bacterial endocarditis is one of the most common complications of intravenous drug abuse. Intravenous drug abusers inject pathogenic organisms along with their illicit drugs. In such patients, 80% have no underlying cardiac lesion and the tricuspid valve is infected in half of cases. Septic pulmonary emboli characterize tricuspid valve endocarditis in drug addicts. Despite antibiotic therapy, a third of cases of endocarditis caused by S. aureus are fatal. Other risk factors for bacterial endocarditis include aging, diabetes, pregnancy, transient bacteremia and prosthetic valves. The most common predisposing condition for bacterial endocarditis in children is congenital hea disease. The other choices primarily affect the left ventricle. Tricuspid stenosis is distinctly uncommon and does not occur rapidly.