Presentation of Case A 57-year-old woman was admitted to the hospital because of dyspnea, chest pain, and a mass in the right atrium and ventricle. The patient had been well until three days earlier, when she experienced the onset of dyspnea, which persisted. That night she was awakened by severe right-sided pleuritic chest pain. On the following day the pain recurred, and she coughed up gross blood; she was admitted to another hospital. The hematologic laboratory values are presented in Table 1. The lactate dehydrogenase level was 1119 U per liter (normal, 313 to 618). The values for urea nitrogen, creatinine,.