Hi Again Science Maniac,
We can often forget that the heart too need good oxygen and nutrients supply in order for it to work effectively, pumping blood around the body.
The blood vessels supplying the heart with oxygen and nutrients is called the coronary arteries. Heart attacks happen when one or more of these arteries are blocked, and a specific part of the heart is then left without any oxygen or nutrients. Heart cells in is part of the heart will die and so this part of the heart will be permanently damaged.
The symptoms of a heart attack can be severe chest pain and /nausea.