The appearance of perivalvular cavities (PCs) in patients with infectious endocarditis (IE) was studied by transesophageal echocardiography (TEE) color Doppler examinations to determine whether the color Doppler TEE presentation was in keeping with the current concept of PCs representing abscesses. Two heart centers participated in the study. Videotape recordings of TEE examinations in patients with IE were analyzed retrospectively for 18 months in both centers, and one center included patients prospectively for an additional 18 months. A total of 118 patients with a diagnosis of IE based on TEE and clinical and laboratory findings were seen during the study period. TEE showed PCs in 34 patients. In 3 patients who died, no autopsy was performed; the PCs were proved at autopsy or surgery in the remaining 31 patients, who constituted the study population. All PCs were echo free at TEE. Apart from one technically inadequate examination, all PCs contained color Doppler signals indicating intracavitary blood flow; the PCs communicated through a narrow channel with high-pressure regions (the left ventricle or the ascending aorta). At surgery or autopsy, only 2 of the 31 patients had pus accumulations besides the blood-filled PCs. At TEE the pus accumulations presented as echo-rich, shaggy tissue thickening. It is concluded that well-delineated, echo-free PCs with intracavitary color Doppler signals at TEE appear to be pseudoaneurysms, and therefore the term abscess should not be used in these cases. Although further studies are needed, our findings suggest that PCs more likely occur by infectious tissue weakening and subsequent dissection rather than as a result of primary abscess formation with secondary rupture. PCs are nevertheless a result of severe IE, and an aggressive surgical approach is still recommended.