In the ambulance:
The paramedic will place electrodes on his/her chest in order to get an electrocardiogram (a.k.a. an EKG which is a graphic record of your heart’s electrical activity). The EKG appears as a linear image on a monitor which may be transmitted to the hospital so the doctors there can evaluate his/her condition before the ambulance even arrives at the hospital.

He/She may also be given:

• Oxygen therapy
• Nitroglycerin
• A pain reliever such as morphine. 
• Aspirin to chew, heparin and other anti-platelet drugs (to un-clot the blockage)

Once he/she reaches the hospital, they will test for the following factors:

• Insufficient blood flow
• Heart muscle damage 
• Abnormal heartbeats
• Troponin (a protein released into the bloodstream when heart cells die)

If they suspect he/she having a heart attack one of the following may be done to try and open the clogged artery:

“Clot-busting” (thrombolytic) Medications
These enter into the body through an intravenous (IV) tube.  They flow through the coronary (heart’s) arteries in order to break up any clots.

Percutaneous Coronary Intervention (PCI)
Cardiac catheterization is the first step of a PCI. This procedure uses a contrasting dye in your blood to determine the exact location of the blockage. Next, a tube (called a catheter) is inserted into an artery in your arm or leg and then up to your heart.  Through the catheter, the doctor can monitor blood pressure, take samples and, if need be, open up a clogged artery.

There are three common methods of opening up a blocked artery.  (Sometimes just one method is used, but often a few are used together):

Angioplasty – An angioplasty is performed by attaching a small balloon to the end of the catheter.  When the point of blockage is reached, the balloon is expanded- pushing the plaque up tight against the walls of the artery and clearing a pathway for the blood. 
  
Stenting – This procedure usually occurs after an angioplasty.  Once the artery is opened up, a stent (tiny expandable wire tube) is inserted into the artery to keep it open. 

Atherectomy – This procedure involves some cutting device (usually a rotating blade or laser beam) removing the plaque from the sides of the arteries after the catheter has reached the blockage. 

Surgery:
In extreme cases, coronary artery bypass grafting surgery (a.k.a. Bypass or CABG) is used for emergency treatment of a heart attack.  When angioplasty and medication are unable to reopen the blocked artery or sometimes when the patient has diabetes, this more invasive surgery may be used.

This type of surgery usually involves your physicians working directly in your open chest cavity.  A heart-lung machine is used to keep the blood and oxygen flowing through your body.  An artery or vein taken from another part of your body is used to bypass (go around) the area of the coronary artery that is damaged. The blood flows into your heart through this new blood vessel rather than the old. 

Recovery from this procedure consists of several more days in the hospital and then 4-6 more weeks of regaining your health (during which you may not be able to do things like drive or return to work). You may have to undergo physical therapy, respiratory therapy, occupational therapy or diet counseling.