Importance of adequately performed Valsalva maneuver to detect patent foramen ovale during transesophageal echocardiography.

Background: Transesophageal echocardiography (TEE) plays an important role in evaluating cardioembolic sources of emboli. The identification of a patent foramen ovale (PFO) is reportedly improved with TEE compared with transthoracic echocardiography (TTE), but the Valsalva maneuver during TEE may be difficult or suboptimal. The aim of this study was to assess the efficacy of the Valsalva maneuver for PFO diagnosis using TEE compared with TTE by evaluating patients with ischemic stroke referred for echocardiography.