A heart attack can be caused by many things but having an embolism is definately one situation that could lead to a heart attack. If a blood clot dislodges and goes into the heart it can certainly bring about a heart attack.
Heart attacks can be caused by other things as well like weakinging of the heart walls. Many things can leave a person ore suseptible to get a heart attack, like smoking, drinking, and being overweight. Having the tendencies to have clots due to thick blood or other root causes can mean that a person is open to have a heart attack because they are open to have a clot and a clot can, if it dislodges, go to the heart.