Dizziness and cold sweats
You should never ever ignore signs like this because this can most probably mean that your brain is not getting the amount of needed blood.
If and when you are feeling symptoms of a heart attack, in this case you will most probably experience discomfort in your chest and this situation will constantly increase as the heart attack itself happens.
Flu or cold symptoms
Experiencing this one can mean a sign as well, because of the fact that these flu or cold symptoms appear few days before the attack, and all of these signs that you should never ignore and definitely deserve that you pay a visit to your doctor.