Postpericardiotomy syndrome (PPS) is an immune phenomenon that occurs days to months (usually 1–6 weeks) after surgical incision of the pericardium (membranes encapsulating the human heart). PPS can also be caused after a trauma, a puncture of the cardiac or pleural structures (such as a bullet or stab wound), after percutaneous coronary intervention (such as stent placement after a myocardial infarction or heart attack), or due to pacemaker or pacemaker wire placement..