That said, ERs have pressure on them to turn over rooms. I've reviewed charts from dozens of young people sent home with cursory evaluations, only to die or be maimed by massive heart attacks within days.
Bottom line: DON'T GO HOME without a thorough evaluation. Second, ask for "serial" cardiac enzymes that are repeated two or three times, every four to six hours. Third, ask for a repeat ECG to compare to the one you got initially.
Finally, ask for a definitive test before discharge. This may be a treadmill stress test with echocardiography (no radiation) or nuclear imaging (radiation). In some ERs, the CACS or the advanced coronary CT angiogram may be available. If you're not severely allergic to iodine dye, this is by far the most accurate way to be sure your arteries are clean. If they aren't clean, a cardiologist will have to evaluate your status, but you'll know the score and -- most importantly -- be alive.