Multiple: Heart Attack
Multiple: Heart Attack
A heart attack, also called a myocardial infarction or MI, is a potentially fatal health crisis caused by a loss of blood supply to the heart muscle. If normal blood flow is not restored within a few minutes, the tissue begins to die from lack of oxygen. Treatment should be started as soon as possible to prevent permanent damage to the heart.
Heart attacks are not the same thing as heart failure. Heart failure is a condition in which the heart cannot pump enough blood to meet the needs of the rest of the body. It usually develops slowly over a period of years and produces early symptoms like loss of energy or fluid buildup in the feet and ankles rather than sudden chest pain. A heart attack can, however, lead to heart failure.
The classic symptoms of a heart attack are pain in the chest, shortness of breath, nausea, and breaking out in a cold sweat. The patient may feel the pain as pressure or squeezing, a sensation of fullness or tightness, a heavy weight on the chest, or a mild or strong ache in the center of the
chest. The pain may move from one part of the body to another, or extend from the chest to the jaw, arms, neck, or back. The person may also feel dizzy or lightheaded. The pain lasts for twenty minutes or longer, or it goes away briefly and then returns.
Not everyone with an MI has these classic symptoms. Some people may have a tight feeling only in the arms or upper back, feel mild indigestion or clammy skin, or may have trouble breathing. Women, people with diabetes, and the elderly are more likely than men to have mild or vague symptoms that can be easily missed; these are sometimes called silent heart attacks. Silent heart attacks are particularly dangerous because they are easy to ignore.
Heart attacks primarily affect adults. About 1.5 million Americans have heart attacks each year, and about half of them die within a year. Coronary artery disease, the major cause of heart attacks, is the leading killer of both men and women in the United States. Heart attacks are increasing worldwide, including the developing countries.
In the United States, heart attacks affect all races and ethnic groups equally.
Risk factors for heart attacks include:
- Lifestyle issues. People who smoke, consume large amounts of alcohol, or are physically inactive are at increased risk of heart attacks.
- Cocaine use. Cocaine causes blood vessels to tighten, thus potentially cutting off blood supply to the heart. Heart attacks in young adults are often caused by cocaine abuse.
- Family history of heart disease.
- Age. The risk of a heart attack increases after age sixty.
- Sex. Men are more likely to have heart attacks than women up to age seventy, when both sexes have an equal risk.
- High blood pressure and high blood cholesterol levels.
- High levels of emotional stress.
Heart attacks are caused by the loss of blood supply to the heart muscle, a condition known as ischemia. In about 90 percent of cases, blockage of the arteries that carry blood to the heart results from atherosclerosis, hardening of the arteries due to the formation of plaques along the walls of the blood vessel. Plaques are composed of a fatty material made up of dead white cells and cholesterol. If a plaque in one of the arteries supplying the heart ruptures, it can cause a blood clot to form in the artery and block it, thus starving the heart of blood.
What to Do about a Heart Attack
A person having a heart attack needs to get help as soon as possible. If someone is having the symptoms of a heart attack:
- Call 911 within five minutes if possible.
- Call the doctor even if the symptoms go away in five minutes.
- Call for an ambulance to go to the hospital; do not take a private car because that will delay treatment.
- Take a nitroglycerin pill (or give one to the patient) if the doctor has prescribed this type of medicine.
Many people put off seeking help when they notice the warning signs because they are embarrassed to ask for help, do not want to cause trouble for other family members, or do not think their symptoms are serious. Doctors agree that it is much better to go to the hospital and find out that the symptoms have another cause than to wait too long and risk dying of a heart attack. According to the National Heart, Lung, and Blood Institute (NHLBI), about half the people who die from heart attacks die within an hour of their first symptoms and before they reach the hospital.
The remaining 10 percent of heart attacks are caused by sudden spasms in the coronary arteries that shut down the flow of blood to the heart muscle. These spasms may result from cocaine use, a sudden emotional shock, or an abnormality in the shape of the coronary artery.
The major symptoms of a heart attack are:
- Pain in the chest, which may be experienced as an ache, tightness, weight, or a squeezing sensation. The pain may move to the back, neck, arms, or jaw
- Nausea and vomiting
- Shortness of breath
- Breaking out in a heavy cold sweat
Other symptoms of a heart attack may include lightheadedness or dizziness, intense anxiety, coughing, or a feeling that the heart is racing.
Most people having a heart attack will be taken to a hospital emergency room, where they will be asked to describe their symptoms. These questions help the doctor to rule out panic disorder, which is a type of anxiety disorder that can cause people to think they are having a heart attack. In addition to taking the patient's personal and family history of risk factors for a heart attack, the doctor will also take the patient's temperature, blood pressure, and pulse. Listening to the patient's lungs and heartbeat through a stethoscope can help to rule out pneumonia or other diseases that might cause chest pain or difficulty breathing.
The next step is diagnostic tests, which include:
- Electrocardiogram (ECG or EKG). An ECG or EKG measures the heart's electrical activity. Injured heart muscle makes unusual patterns or tracings on the paper printout produced by the ECG machine. If only a small amount of the heart muscle has been affected, the ECG may not show any abnormal patterns.
- Blood tests. These are done to confirm the diagnosis of a heart attack or to make sure that the electrocardiogram did not miss a small heart attack. Injured heart muscle leaks small amounts of enzymes into the bloodstream, which can be detected in a blood test. The emergency room doctor may repeat this blood test after several hours because it takes time for these enzymes to show up in the patient's blood.
- Chest x ray. A chest x ray may be done to see whether the patient's lungs are normal.
- Coronary angiography. Coronary angiography is a type of x-ray study in which the doctor threads a long thin tube called a catheter into the heart through an artery in the arm or upper thigh. A dye that will show up on x ray is injected into the bloodstream through the catheter. This test allows the doctor to find the location of the blockage in the coronary artery.
Treatment of a heart attack begins before the diagnosis is confirmed. The emergency room doctor will give the patient oxygen to help with breathing, aspirin to prevent further blood clotting, nitroglycerin to speed up the blood flow through the coronary arteries, and morphine or another pain reliever to make the patient comfortable.
The next step is the administration of clot-busting and blood-thinning drugs. These drugs can improve the patient's chances of survival and reduce the long-term damage to the heart. The patient may also be given beta-blockers, a group of drugs that slow down the heart rate and lower blood pressure; statins, drugs that lower blood cholesterol levels; or medicines to treat abnormal heart rhythms, which often develop after a heart attack.
In some cases the patient may need surgery. The two operations that are most commonly performed are coronary artery bypass surgery and coronary angioplasty. In bypass surgery, the surgeon takes a piece of a healthy artery from another part of the patient's body and sews it in place to go around a blocked coronary artery. This procedure will restore normal blood flow to the heart. In a coronary angioplasty, the surgeon inserts a catheter with a special balloon tip into the coronary artery. When the catheter is in the proper position, the balloon is expanded, which reopens the blocked artery. The surgeon will then insert a stent, which is a tube made of metal mesh, to keep the artery open.
Patients who survive their heart attack usually undergo rehabilitation after they leave the hospital. Rehabilitation includes lifestyle changes and psychological counseling as well as medications to keep the heart healthy.
The prognosis for recovery from a heart attack depends on how quickly the patient is diagnosed and treated as well as his or her age and overall health. About 30 percent of people do not survive their first heart attack; another 5–10 percent die within a year after the event. About half of
patients diagnosed with a heart attack will need to be rehospitalized within a year.
A person who lives through the first two hours after the attack is likely to survive but may have complications like heart failure or blood clots in the lungs. Patients who do not have complications may recover completely.
People who have already had a heart attack can lower their risk of a second by taking a daily aspirin, other blood-thinning medications, cholesterol-lowering medications, beta-blockers, or other drugs that the doctor may prescribe to lower the strain on their heart muscle.
People who have not yet had a heart attack can lower their risk by:
- Quitting smoking or not starting in the first place.
- Getting regular medical checkups. This precaution is important because risk factors for heart attacks like high blood pressure, high cholesterol levels, and diabetes have no symptoms in their early stages.
- Avoiding using cocaine and drinking large quantities of alcohol.
- Keeping one's weight at a healthy level and getting regular exercise.
- Controlling blood pressure.
- Learning how to manage emotional stress.
- Eating a low-fat diet rich in fruits and vegetables.
People are much more likely to survive heart attacks than they were in the 1960s because of the introduction of clot-busting drugs and improvements in heart surgery. New drugs to treat heart attacks are currently being studied as well as the effectiveness of using bone marrow or stem cells to help repair injured heart tissue.
SEE ALSO Coronary artery disease; Hypercholesterolemia; Hypertension; Panic disorder; Stroke
WORDS TO KNOW
Atherosclerosis: Stiffening or hardening of the arteries caused by the formation of plaques within the arteries.
Cholesterol: A fatty substance produced naturally by the body that is found in the membranes of all body cells and is carried by the blood.
Ischemia: Loss of blood supply to a tissue or organ resulting from the blockage of a blood vessel.
Plaque: A deposit of cholesterol along the inside wall of an artery.
Stem cell: A type of unspecialized cell that can reproduce itself and differentiate into different types of specialized cells. Stem cells act as a repair system for the body.
Chung, Edward K. 100 Questions and Answers about Heart Attack and Related Cardiac Problems. Boston: Jones and Bartlett Publishers, 2004.
Phibbs, Brendan. The Human Heart: A Basic Guide to Heart Disease, 2nd ed. Philadelphia: Lippincott Williams and Wilkins, 2007.
Rimmerman, Curtis Mark. Heart Attack: A Cleveland Clinic Guide. Cleveland, OH: Cleveland Clinic Press, 2006.
Farrell, Patrick, Gina Kolata, and Erik Olsen. “Heart Disease, the No.1 Killer.” New York Times, March 2007. Available online at http://www.video.on.nytimes.com/index.jsp?fr_story=691db69642099ef35fdca7aa0d9a8bc7365db79e (accessed on September 17, 2008). This is an online video that takes about four and a half minutes to play.
American Heart Association HeartHub. Heart Attack. Available online at http://www.hearthub.org/hearthub/hc-heart-attack.htm (accessed on September 17, 2008).
eMedicine Health. Heart Attack. Available online at http://www.emedicinehealth.com/heart_attack/article_em.htm#Heart%20Attack%20Causes (accessed on September 16, 2008).
KidsHealth. Heart Disease. Available online at http://www.kidshealth.org/kid/grownup/conditions/heart_disease.html (updated February 2007; accessed on September 17, 2008).
National Heart, Lung, and Blood Institute (NHLBI). Act in Time to Heart Attack Signs. Available online at http://www.nhlbi.nih.gov/actintime/video.htm (accessed on September 17, 2008). This is a 13-minute video about the warning signs of a heart attack and the importance of getting help quickly.
National Heart, Lung, and Blood Institute (NHLBI). What Is a Heart Attack? Available online at http://www.nhlbi.nih.gov/health/dci/Diseases/HeartAttack/HeartAttack_WhatIs.html (updated March 2008; accessed on September 16, 2008).