coronary heart disease
The most common cause of myocardial infarction caused by coronary artery disease. To carry out the arduous task of pumping blood, the heart muscle needs oxygen-rich blood supply, which comes from the coronary artery tissues. Coronary heart disease is the end result of a complex process called atherosclerosis (commonly called "hardening of the arteries"). There are various stages in this process, and some of them are not known at all:
* A number of environmental or physical factors involved in triggering an excessive amount of unstable particles known as oxygen free radicals, which bind to and alter other molecules in a process known as oxidation. (The particles are released as a normal part of the internal processes of the body, but certain environmental toxins, such as tobacco, can produce an excessive amount)
* When free radicals are released from the artery wall, react with low density lipoprotein (LDL), (Lipoproteins are spherical shaped bodies that carry cholesterol and LDL is also known as "bad cholesterol").
* Cholesterol precipitated a thick layer of oxidized LDL in the arterial wall.
* Cholesterol accumulates.
* The wound in the artery during this process to warn the immune system to release white blood cells at the point (particularly those called neutrophils and macrophages. This starts a process called the inflammatory response and significant danger.
* The macrophages "eat" foreign objects literally, in this case the oxidized cholesterol and become foam cells, which are attached to the muscle cells of artery walls, making them grow.
* Over time cholesterol harden and form plate, which accumulates in the arterial wall.
* The immune system, detecting other damage, release of other factors called cytokines that attract white blood cells and perpetuate the whole cycle, causing persistent lesions in the arteries.
* The walls in the injured vessel does not produce enough nitric oxide, a substance essential to maintain the elasticity of arteries.
* In the long run, the artery calcified (hardened) and inelastic range narrower (a condition known as stenosis). Since this process continues, blood flow slows and prevents oxygenated blood to the heart.
* This lack of oxygen in vital cells is called ischemia. When it affects the coronary arteries, causing lesions in cardiac tissues.
Events of myocardial infarction may occur as a result of one or two effects of atherosclerosis:
* If the artery is completely blocked and ischemia are so extensive that the heart tissue is deprived of oxygen, cells die the same.
* If the plaque itself develops fissures or tears. Platelets stick to the point of it to cover the plate and form a blood clot (thrombus). So a heart attack can occur when blood clots form completely blocking the passage of oxygenated blood to the heart.
angina
Angina is the primary symptom of coronary artery disease and, in severe cases of myocardial infarction. Usually experience pain in the chest. Often referred to as unstable angina (estimated) or unstable (less predictable and a sign of a more serious situation). Angina itself is not a disease. Considerable evidence suggests that, in fact, the onset of angina within 48 hours before myocardial infarction may be protective, possibly by conditioning the heart to resist damage from the attack.
