A woman with progressive lethargy and sudden onset of shortness of breath.

A 65-year-old Caucasian woman presented to the emergency department with rapidly worsening shortness of breath. On presentation she was tachycardic and tachypnoeic with reduced (85%) oxygen saturation. Cardiovascular examination revealed elevated jugular venous pressure with positive Kussmaul's sign, pulsus paradoxus and muffled heart sounds.