Most deaths from heart attacks occur within from the onset of symptoms.

2 hours

The other term for heart attack is myocardial infarction (MI) and these occurs when the blood flow that brings oxygen to the heart muscle is severely reduced or cut off completely due to blood clot or the heart muscle become narrow from a buildup of fat, cholesterol and other substances that together are called plaque. 

The heart muscle starts to die within 80-90 minutes after it stops getting blood supply, and this critical time is a window of opportunity that influences a patient's survival and quality of life following a heart attack. If no medical intervention is done within two hours from the onset of symptoms, death occurs.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."