Acute myocardial infarction is the medical term for the event commonly referred to as a heart attack. One of the leading causes of morbidity and mortality in America and most other industrialized nations, myocardial infarction involves death to tissues of the heart due to a blockage-related inability of sufficient oxygen to reach the organ.

Since 90 to 95 percent of individuals in the United States that experience myocardial infarction and are admitted to a hospital survive, it is important to know the warning signs of the condition so that medical help can be obtained in time. Approximately 300,000 Americans die from heart attacks each year before they reach a hospital. Though symptoms of a heart attack vary, they frequently include chest pain or pressure that may radiate into the jaw, shoulders, arms, or back, shortness of breath, nausea, vomiting, lightheadedness, sweating, and anxiety. A significant number of individuals only experience very mild symptoms that may go unnoticed, in which case the myocardial infarction is sometimes referred to as a silent heart attack.

Myocardial infarction is commonly related to the gradual accumulation of cholesterol plaques in the arterial walls known as atherosclerosis. Atherosclerosis is characterized by a narrowing of the lumenal space within arteries and hardening of arterial walls. When atherosclerosis occurs in coronary arteries, there is a risk that a plaque may rupture and a blood clot will form over top of it. If this clot becomes so large that it blocks the blood flow through the artery, acute myocardial infarction occurs. The precise reason that cholesterol plaques rupture and form blood clots is not well understood, but there are a number of factors that can contribute to the event. Some of the best-known contributing factors include high blood pressure, adrenaline levels, and LDL cholesterol, as well as smoking and diabetes mellitus.

When someone suffers an acute myocardial infarction, the primary objective is reperfusion, the restoration of blood flow to the heart. Reperfusion provides the best result if it is achieved within the first 4 to 6 hours after a myocardial infarction occurs. If blood flow is restored after that amount of time, irreversible necrosis usually has already taken place. Thus timely diagnosis and treatment are extremely important for sufferers of heart attacks. Electrocardiograms, magnetic resonance imaging, and a thrombolysis in myocardial infarction (TIMI) risk score are often used to aid in diagnosis, but must be carried out rapidly.

Approximately 80 percent of coronary arteries blocked by blood clots can be readily cleared with intravenous thrombolytic medications, including tissue plasminogen activator (TPA) and tenecteplase (TNK). If such medications are unsuccessful or cannot be used due to other health conditions, then the more direct method of coronary angiography and percutaneous transluminal coronary angioplasty (PTCA) becomes necessary for opening the artery, a procedure that is sometimes accompanied by stenting. If the patient does not respond to PTCA, coronary artery bypass grafting surgery is usually the final resort. Other treatments that may be utilized at various times during treatment for acute myocardial infarction include nitrates and angiotensin converting enzyme (ACE) inhibitors, which dilate blood vessels, beta-blockers, which are antagonists of adrenaline, and oxygen, which can help minimize the extent of damage to the heart.

There are a number of steps that individuals can take to help prevent the occurrence of an acute myocardial infarction. Two of the most important of these steps are controlling blood pressure and cholesterol levels in the body. Consuming a diet that is low in fat and rich in fruits and vegetables often aids in achieving these steps, and also contributes to the maintenance of a healthy weight, another activity that can be key in staving off myocardial infarction and other heart problems. Similarly, regular exercise, which facilitates weight control and increases the fitness level of the heart, is usually recommended to help decrease the risk of such problems.

Myocardial Infarction at 10x Magnification - Blood tests that measure the level of cardiac enzymes released into the circulatory system by dying heart muscle are useful indicators of heart attacks, but take such a long time to complete that they are only useful in the confirmation of a diagnosis, rather than the diagnosis itself.

Myocardial Infarction at 40x Magnification - Oftentimes initial treatment of acute myocardial infarction will consist of an anti-platelet medication, such as aspirin, and an anti-coagulant, such as heparin or warfarin. Together these medications can effectively prevent additional clotting of the blood from taking place.

Myocardial Infarction at 10x Magnification - Some doctors recommend a regimen of aspirin to aid in prevention of myocardial infarction if other risk factors cannot be eliminated, but such action should always be discussed with a health care professional before it is undertaken due to possible side effects.