Greek shipping heiress Christina Onassis died of acute pulmonary edema, or accumulation of fluid in the lungs, a judge said in Buenos Aires. Judge Juan Carlos Cardinali said the information was included in a partial report he received on an autopsy performed on Onassis after she died Saturday, possibly of a heart attack. Heart failure can cause pulmonary edema. However, the judge said he still is awaiting a determination of the cause of the edema and results of other laboratory tests. A local news agency quoted him as saying investigators are focusing on the possible "excessive ingestion of barbiturates."