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Analysis of 99 M-mode echocardiograms recorded during and up to 144 months after healing of active bacterial endocarditis limited to the mitral valve in 27 patients disclosed the following: (1) Little to no change occurred in the echocardiographic size of the vegetations during the first 6 weeks after diagnosis and institution of appropriate antibiotic therapy unless a major systemic embolus occurred. (2) The echocardiographic size of the vegetations did not determine the amount of cardiac damage or dysfunction produced by the valvular infection. (3) The larger the vegetations by echocardiogram, the greater was the likelihood of a clinical event compatible with a systemic embolus. (4) The gravest prognostic sign yielded by the echocardiogram was evidence of rupture of chordae tendineae. (5) Although a useful adjunct to diagnosis before appropriate antibiotic therapy was instituted, once bacteriologic cure was achieved, the echocardiogram was of limited value in delineating an active from a heated vegetation. (6) The echocardiographic appearance of the vegetations was not determined by the type of infecting bacterium.

Analysis of 37 M-mode echocardiograms recorded during the period of active bacterial endocarditis (ABE) involving the aortic valve (AV) in 17 patients disclosed one or more echocardiographic abnormalities involving the aortic valve cusps or their immediate vicinity in 15 (88%), including "shaggy" echoes indicative of vegetations in 12 (71%). Of the 12 patients with echocardiographic evidence of AV vegetation, 11 developed overt congestive heart failure (CHF) and either died or had AV replacement, and seven had clinical events compatible with systemic emboli; of the five patients without echo-demonstrated vegetations, only one had CHF, none had AV replacement, two died, and one had a systemic embolus. In comparison to our previously reported echocardiographic observations in patients with ABE involving either the mitral (29 patients) or tricuspid valve (23 patients), infection involving the AV was far more liable to produce overt CHF and systemic emboli, to necessitate valve replacement, and to cause death during the period of active infection.

Echocardiographic observations are described in 10 patients with right-sided bacterial endocarditis. Six of the nine patients with tricuspid regurgitation had shaggy echoes on the tricuspid valve, which were confirmed to be vegetations on autopsy in two patients. In six patients, right ventricular dilatation was present, and paradoxic septal motion was seen in four. In one of the patients with pulmonic valve endocarditis, the pulmonic valve and right ventricular outflow tract revealed the shaggy echoes in diastole, along with systolic fluttering of the pulmonic valve, right ventricular dilatation and paradoxic septal motion. When the findings are supplemented to the clinical picture, echocardiography is found to be a useful noninvasive adjunct in the diagnosis of acute vegetative bacterial endocarditis involving the right side of the heart, especially if other clinical features, e.g., fever, leukocytosis and positive blood cultures are absent.