Subacute bacterial endocarditis, more accurately designated as endocarditis lenta, is a slow, progressive disease in which vegetations are formed on valves and endocardium. These vegetations become organized and are followed by the production of new vegetations, so that ultimately the mass may be large, composed chiefly of vegetations and more deeply of granulation tissue and cicatrization. The micro-organisms responsible for the disease are principally those of alpha streptococci of the viridans group and gamma nonhemolytic streptococci. The cocci are readily stained in the superficial layers of the vegetations and less readily in the deeper fibrotic and calcified layers. A therapeutic agent, to be effective, must, therefore, be brought in contact with these vegetations over a long period of time in order to reach the cocci trapped in the deeper recesses of the vegetations.
The mortality of endocarditis lenta until the advent of antibiotics was almost 100 per cent. Lichtman,1
TREATMENT OF SUBACUTE BACTERIAL ENDOCARDITIS. JAMA. 1951;145(10):734–735. doi:10.1001/jama.1951.02920280046011