Agitated Saline Contrast Echocardiography in the Identification of Intra- and Extracardiac Shunts: Connecting the Dots

Agitated saline contrast studies are an essential component of contemporary echocardiography. Agitated saline contrast plays a critical role in the elucidation of intracardiac versus intrapulmonary shunting and can have major therapeutic implications, particularly in light of the evolution of percutaneous treatment options for atrial septal defects or a patent foramen ovale. Despite their perceived simplicity, however, there are numerous pitfalls of these investigations that can occur during their performance and interpretation. As such, the authors review the “bubble study” in identifying intracardiac and extracardiac shunts, including the history of its development, the physics and physiology of contrast enhancement, how to optimally perform and interpret an agitated saline contrast study, and its safety in unique populations.