To the Editor: The echocardiogram on the cover of the June 1, 1999, issue of Circulation is a beautiful illustration of an impending paradoxical embolism. Unfortunately, neither the text1 nor the key words of the article made any mention of this condition. Impending paradoxical embolism2 is a surgical emergency. This diagnosis would not have been possible before the advent of echocardiography. However, to diagnose paradoxical embolism, contrast echocardiography should be performed during and after a Valsalva maneuver.3 The mere establishment …