Arterial emboli of venous origin.

In a small but significant group of patients with documented systemic emboli, a source is never determined. It is in this group of patients that an arterial embolus of venous origin should be considered. During the past 20 years, we identified four patients who fulfilled the diagnostic criteria for an arterial embolus of venous origin. In each, the diagnosis was made during life. In addition, we reviewed the 40 additional patient reports in the literature that appeared to meet the criteria for the diagnosis of venous origin arterial emboli. Noninvasive methods were useful in determining the presence of thrombus in the venous system, and right to left shunting across an intracardiac defect. We conclude that treatment with heparin is the mainstay of therapy, and that caval interruption should be used only on a selective basis.