Patent foramen ovale not so patent.

Transesophageal echocardiography (TEE) with agitated saline contrast is the most sensitive tool for diagnosing patent foramen ovale (PFO), but false positives can result. We report a patient who underwent a TEE during the study of a cryptogenic stroke. Contrast appeared in the left atrium with the Valsalva maneuver. However, the contrast exit site was not identified, and contrast continued to appear with Valsalva once the saline microbubbles had disappeared. Combined with the contrast characteristics, this suggested a spontaneous contrast phenomenon rather than a PFO. This phenomenon must be kept in mind to avoid overdiagnosing PFO.