[A simple method for enhancing interatrial right-to-left shunt in the diagnosis of small atrial septal defect using contrast echocardiography (author's transl)].

Commonly used contrast echocardiography is often inadequate to detect a small right-to-left (R--L) shunt in minimum atrial septal defect (ASD). We found that the diagnostic accuracy in ASD could be significantly improved by simply employing a Valsalva maneuver immediately followed by a Müller maneuver to enhance the R--L shunt. This procedure enabled contrast echo to be more clearly detected in both the left atrium and left ventricle, compared with conventional contrast echocardiography. The new technique was successful in diagnosing ASD in 5 patients with Qp/Qs ratio less than 2 determined by right heart cardiac catheterization. In conclusion, the diagnosis of a small ASD is greatly improved by simply employing this new procedure of a Valsalva-Müller maneuver during contrast echocardiography.