Heart Attack Introduction - OmniMedicalSearch.com (Myocardial Infarction)

Heart attack (also known as myocardial infarction) is the diagnosis term used to describe the death of a heart muscle or cells (myocardial necrosis) due to the loss of oxygen rich, arterial blood supply by a blockage. Myocardium is the name of the heart muscle that pumps blood into the body through a well organized system of blood vessels, and infarction is the medical term describing the death of tissue due to interference with its oxygen-rich blood supply.

A heart attack occurs as the result of a blockage that developed within one or more coronary arteries which supply the heart muscle with blood. The heart muscle is similar with any other muscle in the body and requires oxygen-rich blood to function normal. When the oxygen level decreases or drops completely, its tissue suffers serious damage.

Coronary arteries are the blood vessel system that encircles the heart like a crown and supplies blood to and from the heart muscle (myocardium) itself. The blockage is a direct cause of coronary artery disease, a medical condition that affects the arterial blood vessels due to accumulation of fatty deposits and fibrous tissue (called plaque) in the walls of the arteries. When the arterial plaque loses their surface layers, blood can start coagulating on the rough surfaces of the blood vessel wall. In time, this process can lead to a sudden obstruction of the entire blood vessel. The acute or total reduction of blood supply to a certain portion of the myocardium causes serious tissue damages. The heart tissue starts to die when it is deprived of oxygen-rich blood for more than 30 minutes. When the loss of heart muscle is so great that the heart's normal functioning cannot be maintained or the heart electrical functioning (pumping blood) is impaired, the heart attack can be lethal.

In rare cases, a heart attack can be caused by a spasm of a coronary artery. The coronary artery spasm can restrict or spasm off and on the artery walls disrupting thereby the flow of blood (known in medical terms as ischemia) to a portion of the myocardium. A coronary artery spasm affects normal coronary arteries or those affected by atherosclerosis. It usually occurs when the person is resting.

Unfortunately, heart attacks are the leading cause of mortality and morbidity in the United States as well in most industrialized nations around the world. . Among adults, a heart attack is the cause of 1 out of every 5 deaths. According to the National Institute of Health, more then 1.2 million cases of heart attacks occur every year in the United States and about 500,000 to 700,000 of them result in death.

Approximately one third of all patients that suffer an ischemic heart attack die within the first 24 hours of the onset of ischemia. More than half of cases of death caused by heart attacks occur in a pre hospital setting, and around 300,000 people die annually of heart attacks before receiving treatment. However, the survival rate among hospitalized patients that suffered a heart attack is approximately 90 to 95 percent.

Conditions & Diseases: Cardiovascular System

Heart Attack (Myocardial Infarction)

Heart Attack Introduction and Overview