You're out of breath -- maybe having chest pains.

But are you actually having a heart attack?

Researchers are developing a new test that could more easily and quickly determine what's going on.

It detects levels of a heart muscle protein called Troponin.

"When the heart has damage, this protein leaks into the blood stream. Normally there should be no protein like this, no Troponin in the blood, because it should be in the heart."

Experts say if the test is as reliable as it appears, it could also rule out who is not having a heart attack faster.