Thirty cases of paradoxical embolism are reviewed to consolidate clinical presentations and common predisposing factors. The presence of patent foramen ovale in the great majority of these patients in association with maneuvers that transiently elevate right atrial pressure is emphasized in relation to the pathophysiology of the disorder. Contrast echocardiography with provocative maneuvers such as Valsalva and cough are discussed and treatment options highlighted. The underdiagnosis of paradoxical embolism is discussed, and its potential importance in other more common vascular diseases addressed.