Pericardial pressure in acute and chronic tamponade

Volume curves recorded from data acquired during pericardiocentesis. Curve A (in red) plots data from a patient with hyperacute tamponade that followed laceration of a coronary artery during an angioplasty-stenting procedure. Note the extreme elevation of pericardial pressure and that withdrawal of only 100 mL, half the volume we could aspirate, lowered the pressure to 10 mmHg. Curve B (in blue) plots data from a patient who had a history of prior pericarditis, assumed to be of viral etiology. Subsequently, he developed a chronic pericardial effusion that reached at least 1500 mL in volume. At the time of presentation to our service, the jugular venous pressure was 22 mmHg. Aspiration of 300 mL of pericardial fluid reduced the pericardial pressure to 10 mmHg, and removing another 600 mL achieved a nearly normal pericardial pressure. Aspiration of the remaining large effusion did not affect pericardial pressure. The curves of cases of intermediate acuity or chronicity would fall between these two extremes.