One type of heart attack? No! Two

 A hundred years ago and more, it typically was recorded that a heart attack was singular-of one type or cause. The commonly then said cause by the medical world directed to what is described as a blocked artery, plaque or fat.

It is still being treated much the same today despite new findings.

In recent decades, new studies with new capacities have found that there is an actual, different way heart attacks develop other than blocked arteries, etc.

The new, second, way is found through the heart's electrical system which can 

misfire and cause serious heart muscle contraction and valve like atrial fib and ventricle fib which if left to further development can also prove fatal, other than the more common labeled type of old although some institutions don't readily diagnose them.