“How many chest compressions should I do in case of a heart attack?”

If someone is having a heart attack, you should call 911. If you plan on saving a life, you need proper training in CPR and this best is done by taking a basic life support class. They will also teach you about the use of AED defibrillators that may be at the scene of a person needing immediate medical help. Chest compressions may not necessarily work.