Massive right atrial thrombus associated with a Chiari network and a Hickman catheter.

The Chiari network is an embryologic remnant that is said to be present in only 1.5-3% of adults. It is rarely of clinical importance but may, very infrequently, be the site of thrombosis. The authors describe a patient in whom a massive right atrial thrombus formed on a Chiari network, leading to intermittent tricuspid obstruction. The thrombus had formed after the use of a Hickman catheter for the administration of cytotoxic chemotherapy. They can find no previously recorded examples of sufficient thrombus forming on a Chiari network to threaten life by obstructing the flow of blood through the heart.