Final answer:
Excess fluid in the pericardial cavity puts a patient at increased risk of cardiac tamponade, a serious condition that can lead to decreased cardiac output and death without treatment.
Step-by-step explanation:
If a patient has excess fluid in the pericardial cavity as seen on an echocardiogram, they are at increased risk for cardiac tamponade. This condition occurs when excess fluid, often blood, accumulates in the pericardial cavity. The pressure from this fluid prevents the heart from fully relaxing and properly filling with blood, leading to decreased cardiac output and potential organ failure. Cardiac tamponade can occur from a variety of causes, including trauma, pericarditis, and complications from surgery. Without treatment, such as drainage of the excess fluid, cardiac tamponade can be fatal.