Pilot

In the opening scene the surgeon says "it may be tamponade". Penetrating chest wounds often lead to cardiac tamponade. Cardiac tamponade is when the blood begins to leak into the sac (pericardial sac); that surrounds the heart. When it fills. The blood in the sac begins to put pressure on the beating heart and affects the rhythm. It isn't necessary to open the chest to diagnose or treat this condition. Tamponade is usually first seen on a cardiac monitor as reduction in heart rate. The rhythm of the patient in this episode shows no rhythm disturbance. Tamponade is life threatening and can be treated by inserting a long needle into the pericardium (sac) to reduce the quantity of blood surrounding the heart. This is a procedure not uncommon in the ER, and or ICU's of hospitals. And this needle procedure (pericardiocentesis) gives the doctor time to do what's necessary to correct the problem.

References Mean Girls (2004)