Determination of site of infection in endocarditis.

Medical-surgical treatment of antibiotic refractory endocarditis requires determination of the site of infection, which is not always possible with conventional cardiac catheterization. The cases of two patients with right-sided endocarditis who survived after combined medical-surgical therapy are presented. One had persistent Pseudomonas aeruginosa bacteremia and three possible sites of infection. Multiple quantitative blood cultures proximal and distal to each suspected site indicated the pulmonary valve alone was infected. The second had sustained bacteremia with three enteric organisms and no apparent valvular abnormality. Quantitative cultures excluded the abdomen as the continuing source of bacteremia and suggested the tricuspid valve was infected. This was confirmed by a second catheterization using multiple cultures in conjuction with dye dilution studies, intracardiac phonocardiography, and angiography. These bacteriologic and cardiologic techniques may be especially useful in detecting right-sided endocarditis and may also be helpful in detecting concomitant infection of both sides of the heart.