My sister has developed heart contusion. what is it exactly?

It's like....: Slamming the door on your finger - ouch! cardiac contusion follows strong thump to the chest or rapid deceleration injury like in an auto accident. Blood samples and ekgs can look just like a heart attack. Fluid can accumulate in the sac around the heart (pericardial effusion). It heals with time. Cardiologists treat complications while waiting for nature to complete its work.

Trauma to heart: Trauma to the chest causes trauma to the heart, which bruises the heart muscle.