Clinical implications of large vegetations in infectious endocarditis.

Thirty-four patients with clinical infectious endocarditis were examined by M-mode and two-dimensional (2D) echocardiography. Vegetations were identified in 16 patients (47%) by M-mode and in 27 patients (87%) by 2D echocardiography. Vegetations identified by 2D echocardiography were categorized as small (less than 5 mm), medium (5 to 9 mm), or large (greater than or equal to 10 mm). Large vegetations were caused by a variety of organisms, had a higher incidence of surgery (44% v 0%), and had no increased incidence of stroke or death. The larger the vegetation, the more detectable it was by M-mode. Aortic valve vegetations were associated with a higher incidence of congestive heart failure (CHF) (67% v 14%) and stroke (44% v 9%). Four patients with large aortic valve vegetations had the highest complication rate; CHF developed in all four, two had valve replacement, one had a stroke, and two died.