Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Heart Attack ?
    ### Response:
    Each year over a million people in the U.S. have a heart attack. About half of them die. Many people have permanent heart damage or die because they don't get help immediately. It's important to know the symptoms of a heart attack and call 9-1-1 if someone is having them.
    