Myocardial Infarctions (or in laymen's terms: Heart Attacks), are usually caused by plaque build up in the coronary arteries. I don't mean plaque as in what you find on your teeth every morning, I'm talking about fat that builds up inside the walls of your arteries, and harden over time, also called Coronary Artery Disease (CAD) or just plain Heart Disease.
The signs and symptoms, more often than not, are fairly simple. Chest pain: This can be simple discomfort, tightness, pressure, or severe pain. It doesn't matter, it amounts to the same thing. If your chest pain radiates from the left shoulder down your left arm, and up along your jaw, you should get checked out immediately, call your Primary Care Physician and take an Aspirin 325mg, 81mg (baby aspirin) will do just as well.
Another sign to possible heart attack is SOB (Shortness of Breath), this usually goes along with the chest pain. If you are just at the beginning, usually the chest pain and SOB, will worsen upon exertion, and lessen when resting, but it may not completely fade away. That is usually the time to call your family practitioner, or cardiologist if you have one.
Typically, the standard reactions to these signs and symptoms of a possible heart attack, is of course to be seen by your physician. Depending upon the exact nature of your symptoms will determine the type of testing to be done. Chest pain and SOB that worsens with exertion will get you into a Stress Test, there are a few types out there for this too. A Nuclear Study uses Adenosine or Thallium (very low grade radioactive material) that will light up your heart and arteries like a Christmas Tree so pictures can be taken.
If there are shadows or artifact shown, it is possible you have a blockage, the next step to that result would be a Cardiac Angiogram. This is where a catheter is inserted into an artery, most of the time in the groin area, but some doctors will use an artery in the arm instead, the catheter will inject dye into the arteries, X-rays will be taken, so the Cardiologist Interventionalist can pin-point the exact spot where the blockage is. If blockages are found, he or she will put in Stents to clear the blockages. Stents are a very tiny wire mesh, that are inserted into the artery via catheter, then inflated by a balloon and clears out all blockages. From this point on, you have a diagnosis of Heart Disease.
Long term treatments will include better diet and exercise, statin medications to keep your cholesterol low (people with heart disease will want there LDL at 70 or below), and medications that will lower platelets, this is to decrease your chances of receiving more stent placements, and/or enduring a heart attack. You will also see your cardiologist every 6 to 12 months, depending on the stability of your diagnosis, a stress test will also be done once a year, sooner if you start experiencing the signs and symptoms of a heart attack.