主动脉瓣示，毒力强的细菌可引发急性感染性心内膜炎，从而导致心脏严重损坏。红棕色的赘生物覆盖瓣膜尖端使其受损，赘生物的一部分可以脱落形成脓性栓子。
The more virulent bacteria causing the acute bacterial form of infective endocarditis can lead to serious destruction, as shown here in the aortic valve. Irregular reddish tan vegetations overlie valve cusps that are being destroyed. Portions of the vegetation can break off and become septic emboli.