Heart Attack

Coronary atherosclerosis is the hardening and narrowing of the arteries that supply blood to the heart muscle. Coronary atherosclerosis is the major cause of heart attacks. Heart attacks are the major cause of sudden unexpected death among otherwise healthy adults in the prime of their lives. Heart attacks are also a significant cause of heart failure (due to weakened heart muscle) in this country.

Heart failure considerably decreases a person's longevity and quality of life. In dollar terms, coronary heart disease is costly. The total cost of coronary artery bypass surgery, coronary angioplasty and stenting, medications, and hospitalizations exceeds 50 billion dollars annually. Coronary atherosclerosis, and hence heart attacks, are preventable. A person can significantly lower his or her risk of heart attack by lowering high blood pressure, controlling diabetes, stopping cigarette smoking, losing excess weight, exercising regularly, and lowering the levels of bad “LDL” cholesterol and increasing the level of the good “HDL” cholesterol in the blood. In recent years, other risk factors for coronary atherosclerosis have been identified. These include a high serum homocysteine level and certain subtypes of LDL cholesterol. The following is a comprehensive review of the causes of atherosclerosis and heart attacks, and the means for their treatment and prevention. What is atherosclerosis?

Atherosclerosis is a gradual process whereby hard cholesterol substances (plaques) are deposited in the walls of the arteries. Cholesterol plaques cause hardening of the artery walls and narrowing of the inner channel (lumen) of the artery. Arteries carry blood that is enriched with oxygen and nutrients to the vital organs such as the brain, heart, kidneys, and liver. Arteries also transport blood to other tissues such as the fingers, toes, nerves, bones, skin, and muscles. Healthy arteries can deliver an ample supply of blood to the organs and tissues. In contrast, arteries that are narrowed by atherosclerosis have difficulty delivering blood to the parts of the body they supply. For example, atherosclerosis of the arteries in the legs causes poor circulation in the lower extremities. Poor circulation in the lower extremities can lead to pain while walking or exercising, deficient wound healing, and/or leg ulcers. Atherosclerosis can also cause the complete blockage of an artery from a blood clot. This complete blockage interrupts oxygen supply and results in tissue injury or death. Thus, the blockage of an artery that furnishes blood to the brain can lead to a stroke (death of brain tissue). Likewise, the blockage of the arteries to the heart can result in a heart attack (death of heart muscle), also called myocardial infarction (MI). What are coronary heart diseases (CHD)?

Coronary atherosclerosis refers to the hardening and narrowing of the coronary arteries. The coronary arteries supply the blood that carries oxygen and nutrients to the heart muscle. When coronary arteries are narrowed or blocked by atherosclerosis, they cannot deliver an adequate amount of blood to the heart muscle. Disease caused by the lack of blood supply to heart muscle is called coronary heart disease (CHD). Coronary heart diseases include heart attacks, sudden unexpected death, chest pain (angina), abnormal heart rhythms, and heart failure due to weakening of the heart muscle.