Bacteremia and the heart: Serial echocardiographic findings in 80 patients with documented or suspected bacteremia

Abstract

We performed serial M-mode and two-dimensional echocardiography at one- to two-week intervals in 57 patients with documented bacteremia in order to define the prevalence and course of cardiac abnormalities, and the role of routine echocardiography, in patients with bacteremia. A control group of 23 patients with clinically suspected bacteremia but negative blood culture results was also studied. The mean number of echocardiograms per patient was 2.4 in the bacteremic group and 2.2 in the control group. A total of 186 echocardiograms were interpreted without any clinical knowledge for the presence or absence of, and serial changes in, valvular vegetation, pericardial effusion, left ventricular dysfunction, and other abnormalities. Nine of 57 bacteremic patients had vegetations, whereas no vegetations occurred in the 23 nonbacteremic control patients (p < 0.05). In four of the nine patients with vegetations, bacterial endocarditis was clinically unsuspected prior to echocardiography, whereas the remaining five patients had clinically evident endocarditis. Of nine bacteremic patients with a risk factor predisposing to endocarditis (intravenous drug abuse in six; valvular heart disease in three), six (67 percent) had a vegetation, whereas only three of 48 (6 percent) bacteremic patients without a risk factor had a vegetation (p < 0.001). Risk factors were present in five non-bacteremic control patients, none of whom had a vegetation. Pericardial effusions were noted in 19 of 57 (33 percent) bacteremic patients and in four of 23 (17 percent) nonbacteremic control patients (p = NS), but no patient had clinically evident tamponade or purulent pericarditis. Global left ventricular dysfunction was noted in 11 of 57 (19 percent) bacteremic patients versus three of 23 (13 percent) nonbacteremic patients (p = NS). On serial study, ventricular dysfunction improved in six of 11 bacteremic patients but in none of the nonbacteremic patients. Other lesions, including valvular prolapse and nonspecific valve thickening, were equally prevalent in both groups. In unselected patients with bacteremia, serial echocardiography rarely demonstrates findings that lead to a change in prognosis or therapy, and thus routine echocardiography is not indicated. However, in bacteremic patients who have either a clear risk factor predisposing to endocarditis or a potential intravascular source of bacteremia, we recommend echocardiography to detect otherwise unsuspected vegetations.