In Reply.
—We are pleased that our work stimulated Del Brutto and colleagues' letter to the editor. As noted in our report, six patients had rightto-left intracardiac shunts demonstrated on contrast echocardiography.1 Findings from the remainder of their evaluations were normal. Some of these patients had their strokes at the time of a Valsalva's maneuver. We postulated that paradoxical cerebral embolism was the most likely cause for their cerebral infarctions. We agree that even the demonstration of intracardiac shunting in this context provides only circumstantial evidence. The same, however, is also true for most clinical diagnoses of cardiogenic cerebral embolism.Standard clinical criteria for diagnosis of paradoxical cerebral embolism are: (1) cerebral arterial emboli without a left-sided cardiac source, (2) right-to-left intracardiac shunting, (3) venous thrombosis, excluding thrombosis of the pulmonary veins, and (4) pulmonary pathology accounting for an acute rise in right atrial pressure. We believe there are obvious shortcomings