SCHOOL OF NURSING
ANATOMY AND PHYSIOLOGY 102
Myocardial infarction is the technical name for a heart attack. A heart attack occurs when an artery leading to the heart becomes completely blocked and the heart does not get enough blood or oxygen, causing cells in that area of the heart to die (called an infarct). Most heart attacks are caused by blood clots, which are in turn caused by atherosclerosis (stiffening and narrowing of the arteries). High blood fats (triglycerides) and LDL or “bad” cholesterol form plaque inside arteries, narrowing the passageway and reducing the amount of blood that can flow through. A person’s lifestyle plays a crucial role in preventing a heart attack or recovering from one. Eating a heart healthy diet and getting at least 30 minutes of exercise 5 days a week (or more) can greatly reduce the risk of heart attack.
Heart attacks happen when an artery supplying your heart with blood becomes blocked. Without blood, the heart doe not get enough oxygen and cells in the heart start to die. The most common cause of blocked arteries is atherosclerosis. No one knows the exact cause of atherosclerosis, but most researchers believe it begins with an injury to the innermost layer of the artery, known as the endothelium. The following factors are thought to contribute to the damage: High blood pressure
Elevated low density lipoprotein LDL ("bad") cholesterol
An accumulation of homocysteine (an amino acid produced by the human body, thought to be a risk factor for heart disease, stroke, osteoporosis, diabetes, and dementia). Smoking
High blood pressure
Elevated LDL ("bad") cholesterol
Once the artery is damaged, blood cells called platelets build up there to try and repair the injury. Over time, fats, cholesterol, and other substances also build up at the site, which thickens and hardens the artery wall. The amount of blood that flows through the artery is decreased, and oxygen supply to organs also decreases. Blood clots may also form, blocking the artery. Rarely, a spasm in a coronary artery (one that supplies blood to the heart) stops blood flow and can cause a heart attack.
Usually, the most recognizable symptom of a heart attack is pain in the middle of the chest that may spread to the back, jaw, or left arm. Less often, the pain spreads to the right arm. The pain may occur in one or more of these places and not in the chest at all. The pain of a heart attack is similar to the pain of angina but is generally more severe, lasts longer, and is not relieved by rest or nitroglycerin less often, pain is felt in the abdomen, where it may be mistaken for indigestion, especially because belching may bring partial or temporary relief. For unknown reasons, women often have different, less identifiable symptoms. About one third of people who have a heart attack do not have chest pain. Such people are more likely to be women, people who are not white, those who are older than 75, those who have heart failure or diabetes, and those who have had a stroke. Other symptoms include a feeling of faintness or actually fainting, sudden heavy sweating, nausea, shortness of breath, and a heavy pounding of the heart (palpitations). During a heart attack, a person may become restless, sweaty, and anxious and may experience a sense of impending doom. The lips, hands, or feet may turn slightly blue. Older people may have unusual symptoms. In many, the most obvious symptom is breathlessness. Symptoms may resemble those of a stomach upset or a stroke. Older people may become disoriented. Nonetheless, about two thirds of older people have chest pain, as do younger people. Older people, especially women, often take longer than younger people to admit they are ill or to seek medical help. Despite all the possible symptoms, as many as one of five...
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