What is the difference between Angina Pectoris and Myocardial Infarction?

In angina there is pain due to decreased blood and oxygen supply to the heart. Once there's enough oxygen the heart tissue goes back to normal. There's stable (something you have been feeling for a long time in the same situation and hasn't changed) and unstable, the dangerous one, which can lead to myocardial infarction (these two are called acute coronary syndrome).
In myocardial infarction, the tissue actually dies, so even after the oxygen is restored, that particular part will never return to normal. Usually there's always a part that is only ischemic (low oxygen) but not dead yet, so its necessary to reperfuse (open those arteries) as soon as possible to save the sick but not dead tissue.
In a few words:
angina: reversible damage
infarction: irreversible, dead tissue.

Angina is more like a warning shot across the bow of a ship. It's telling you that something isn't right with your heart and you need to get it checked.

A myocardial infarction is a heart attack. That means a part of your heart has been damaged, and is a serious and often fatal condition.

Don't fool around with chest pain. Too many people shrug it off, and sadly, die because of it.

1} angina pectoris = is a condition characterized by chest pain that occurs when the muscles of the heart receive an insufficient supply of oxygen. This results when the arteries that supply the heart muscle with oxygenated blood are narrowed by arteriosclerosis.
2} myocardial infarction >>> { (a) myo = muscle + (b) cardial = heart + (c) infarction = blockage of blood circulation } [a+b+c=heart attack}; is usually caused by a blockage in one of the coronary arteries that supply blood to the heart muscle. The blockage typically occurs when a blood clot lodges in an area already narrowed by arteriosclerosis. I hope this helps.

Myocardial infarction (aka heart attack) is what happens to people when the blood supply, and thus oxygen, is unable to reach the heart, resulting in tissue death of the heart.

Angina pectoris is the actual chest pain that one may feel while experiencing a myocardial infarction, or for a variety of other reasons.

Angina Pectoris is the pain one experiences when heart muscle is being deprived of needed levels of oxygen. It occurs as a result of partially blocked coronary arteries. If a coronary artery becomes completely blocked, thereby allowing no blood flow to the part of the heart that is being perfused (given blood) by the artery, the result will be a Myocardial Infarction, otherwise known as a heart attack. When one has an MI, irreparable muscle necrosis (tissue death) occurs at the affected part of the heart. The necrosed tissue will now turn into non-functional scar tissue and the heart's beating power will be reduced. This is why it is always important to keep track of one's level of angina and to report promptly, to a physician, any change from ones baseline condition, including response to medications. Never change dosages of heart medicine without the advice of your physician

Angina pectoris is a crusiating egoning pain experienced on the left side chest wall called precordium may have extension to left arm and left side neck and jaw also or back side of chest with lots of perspiration!It is a symptom arising from low blood supply to heart muscle!!Where as Myocardial Infarction means some part or area of the heart muscle it self is on its death way !or is died and have become non elastic fibre permanently !!this INFARCT patch will remain for ever on the heart surface where as Angina will go away using coronary dilator drugs.Angina may become a cause of Infarction or heart attack arrest !Always YouRmE