Cardiac tamponade is the compression of the heart characterized by the accumulation of fluid in the pericardium (the sac surrounding the heart). This fluid buildup puts pressure on the heart, making it difficult for the ventricles of the heart to fill with blood and resulting in cardiac tamponade. Cardiac tamponade is a medical emergency. Cardiac tamponade occurs in approximately 2 out of 10,000 people. The overall risk of death depends on the speed of diagnosis, the treatment provided, and the underlying cause of the tamponade.

Cardiac tamponade may be caused by any of the following:

• Effusions caused by tumors often lead to tamponade, eliciting bleeding in the pericardium. Blood accumulates more rapidly than a transudate and more commonly causes tamponade.
• Pericarditis, an inflammation of the pericardium, may cause fluid and cardiac tamponade.
• Radiation or drug therapies can cause cardiac tamponade.
• Cancers in or near the heart can leak fluid into the pericardium and cause cardiac tamponade. Tamponade is more common in patients with malignant pericarditis.
• Heart catheterization and invasive surgery, including open-heart surgery and recent heart attack can lead to cardiac tamponade.
• Cardiac tamponade can be caused due to viral or bacterial infection.