How high does your heart rate need to be before you get a heart attack?

Not related. A heart attack can occur at any heart rate if there is a blood clot in the artery or a blockage. If there is a severe narrowing than a higher heart rate will increase the risk of a heart attack as the demand of a higher heart rate would out strip the supply.
Depends. Depends on pre existing coronary artery insufficiency status, age, pre existing co morbidities, anemia, altitude, state of hydration, pulmonary status, presence of valvular pathology, type of rythm to include some. Therefore there is not a majic number that applies to all, it is specific for each heart particular situation.
Varies. If you have normal arteries, no heart rate will cause a myocardial infarction ("heart attack") but rare conditions (wpw etc) can cause very rapid heart rates (eg > 220) that will pump ineffectively because of inadequate filling time. If there's blockage, the hr that is harmful (by increasing myocardial oxygen consumption) will depend on severity and location, age, contractility, and wall stress.

Related Questions

Can panic attack lead to: a) stroke or heart attack due to either hbp being too high at that moment or my heart rate being too too fast? Help

Needs to be high. At 32 years provided you are not morbidly obese severely diabetic or have cardiac issues its unlikely. The panic would have to have your heart beating at almost 200 and your BP would have to be quite high. If you are having a lot of panic attacks speak to your doctor, neurologist, psychiatrist and they may be able to prescribe a medication to stabilize these events. Read more...

My heart rate is usually 60-70 today it's been between 90-100 why? Could this be a sign of heart attack

Tachycardia. Not necessarily. How long have you had it? Is it Persistent now.? Are you anxious? Do you have any infection? Do you have any other symptoms. Tachycardia can be due to many conditions including infection, anxiety Over active thyroid and heart problem. Please see your doctor if it is persistent and it is bothering you. Read more...

My heart rate is 120 but I haven't done anything but shower this morning. Even when I sit down it feels fast. I'm only 17 & scared of heart attack?

Evaluation needed. You should see your primary care. They may want to check your thyroid and your heart. Thanks for trusting HealthTap! Read more...
See Dr. Heart attack unlikely in your age group, but thyroid or other medical issue causing rapid heart rate more likely. Need evaluated by your Dr and likely blood work and an EKG to start to sort things out. Read more...

Does a really fast heart rate cause a heart attack?

No. A fast heart should be investigated. It can be serious and be related to a clot in the lungs, a heart attack, or dehydration. Read more...
Not usual but it can. The fast heart beat which is generated by the lower heart chambers(ventricular tachycardia) can reduce the blood volume generated by the heart and if the subject has low preserve (some narrowing of the coronary arteries or decreased heart function) can cause ischemia t the heart. Read more...