Can you tell me if your heart rate increases during a heart attack?
Increase or irregular heart rate can be a sign of a heart attack, though it can also slow down or become irregular, as well. It depends on the person and the area affected by the blockage that triggers the attack. Here is a link that discusses heart attack symptoms and warning signs, as well as some other articles you might find useful.
Heart Attack Symptoms and Warning Signs
5 Things to Know About Your Heart Rate
Heart Palpitations and Anxiety Attacks: Should You Be Worried?
Hope this gives you the answers you are looking for.