Tricuspid valve endocarditis in adult patients without known predisposing factors.

Four patients with no known predisposing conditions developed tricuspid valve endocarditis. All patients had community-acquired infection with a rapidly progressive course that was complicated by right heart failure and respiratory insufficiency. Pulmonary involvement was prominent in all cases. The infectious process was due to Staphylococcus aureus in three patients and to Streptococcus intermedius in one patient. Three patients underwent early surgical intervention; the outcome was favourable in all cases. It is clear that tricuspid valve endocarditis can occur in the absence of known predisposing factors, and when Staphylococcus aureus is involved, the course of the disease may be acute and rapidly progressive.