It's what is called a "resultative" sentence. The last word emphasizes the result of the action.
For instance :
He knocked the unconscious person. The first person punches the other one, but the latter is already unconscious when he gets knocked.
He knocked the person unconscious. This time, the first one punches the other one until he falls down, unconscious.
As regards your sentence : I tear my heart open
I tear my open heart means I tear my heart, which is already open.
I tear my heart open : I tear my heart till I open it....
Although I think Spanish, I am completely unable to translate it to you.
Hope I've helped you