Heart Attack

The National Heart Lung and Blood Institute (US) has published the following article:

What Is a Heart Attack?

A heart attack occurs if the flow of oxygen-rich blood to a section of heart muscle suddenly becomes blocked. If blood flow isn't restored quickly, the section of heart muscle begins to die.  Heart attacks are a leading killer of both men and women in the United States. The good news is that excellent treatments are available for heart attacks. These treatments can save lives and prevent disabilities.   Heart attack treatment works best when it's given right after symptoms occur. If you think you or someone else is having a heart attack, call 9–1–1 right away.

Overview

Heart attacks most often occur as a result of coronary heart disease (CHD), also called coronary artery disease. CHD is a condition in which a waxy substance called plaque (plak) builds up inside the coronary arteries. These arteries supply oxygen-rich blood to your heart.  When plaque builds up in the arteries, the condition is called atherosclerosis (ath-er-o-skler-O-sis). The buildup of plaque occurs over many years.  Eventually, an area of plaque can rupture (break open) inside of an artery. This causes a blood clot to form on the plaque's surface. If the clot becomes large enough, it can mostly or completely block blood flow through a coronary artery.   If the blockage isn't treated quickly, the portion of heart muscle fed by the artery begins to die. Healthy heart tissue is replaced with scar tissue. This heart damage may not be obvious, or it may cause severe or long-lasting problems.

A less common cause of heart attack is a severe spasm (tightening) of a coronary artery. The spasm cuts off blood flow through the artery. Spasms can occur in coronary arteries that aren't affected by atherosclerosis.  Heart attacks can be associated with or lead to severe health problems, such as heart failure and life-threatening arrhythmias (ah-RITH-me-ahs).  Heart failure is a condition in which the heart can't pump enough blood to meet the body's needs. Arrhythmias are irregular heartbeats. Ventricular fibrillation is a life-threatening arrhythmia that can cause death if not treated right away.

Get Help Quickly

Acting fast at the first sign of heart attack symptoms can save your life and limit damage to your heart. Treatment works best when it's given right after symptoms occur.   Heart attack symptoms include:

• Chest pain or discomfort. This involves uncomfortable pressure, squeezing, fullness, or pain in the center or left side of the chest that can be mild or strong. This discomfort or pain often lasts more than a few minutes or goes away and comes back.
• Upper body discomfort in one or both arms, the back, neck, jaw, or upper part of the stomach.
• Shortness of breath, which may occur with or before chest discomfort.
• Nausea (feeling sick to your stomach), vomiting, light-headedness or sudden dizziness, or breaking out in a cold sweat.

Symptoms also may include sleep problems, fatigue (tiredness), and lack of energy.   If you think you or someone else may be having a heart attack, call 9–1–1 right away. Quick treatment can save your life.  Do not drive to the hospital or let someone else drive you. Call an ambulance so that medical personnel can begin life-saving treatment on the way to the emergency room. Take a nitroglycerin pill if your doctor has prescribed this type of treatment.

Outlook

Each year, about 1.2 million people in the United States have heart attacks, and many of them die. CHD, which often results in heart attacks, is the leading killer of both men and women in the United States.   Many more people could survive or recover better from heart attacks if they got help faster. Of the people who die from heart attacks, about half die within an hour of the first symptoms and before they reach the hospital.

Other Names for a Heart Attack:

• Myocardial infarction (MI)
• Acute myocardial infarction (AMI)
• Acute coronary syndrome
• Coronary thrombosis
• Coronary occlusion

 

What Causes a Heart Attack?

Coronary Heart Disease

A heart attack happens if the flow of oxygen-rich blood to a section of heart muscle suddenly becomes blocked. Most heart attacks occur as a result of coronary heart disease (CHD).   CHD is a condition in which a waxy substance called plaque builds up inside of the coronary arteries. These arteries supply oxygen-rich blood to your heart.   When plaque builds up in the arteries, the condition is called atherosclerosis. The buildup of plaque occurs over many years.   Eventually, an area of plaque can rupture (break open) inside of an artery. This causes a blood clot to form on the plaque's surface. If the clot becomes large enough, it can mostly or completely block blood flow through a coronary artery.   If the blockage isn't treated quickly, the portion of heart muscle fed by the artery begins to die. Healthy heart tissue is replaced with scar tissue. This heart damage may not be obvious, or it may cause severe or long-lasting problems.

Coronary Artery Spasm

A less common cause of heart attack is a severe spasm (tightening) of a coronary artery. The spasm cuts off blood flow through the artery. Spasms can occur in coronary arteries that aren't affected by atherosclerosis.  What causes a coronary artery to spasm isn't always clear. A spasm may be related to:

• Taking certain drugs, such as cocaine
• Emotional stress or pain
• Exposure to extreme cold
• Cigarette smoking

 

Who Is at Risk for a Heart Attack?

Certain risk factors make it more likely that you'll develop coronary heart disease (CHD) and have a heart attack. You can control many of these risk factors.

Risk Factors You Can Control

The major risk factors for a heart attack that you can control include:

• Smoking
• High blood pressure
• High blood cholesterol
• Overweight and obesity
• An unhealthy diet (for example, a diet high in saturated fat, trans fat, cholesterol, and sodium)
• Lack of routine physical activity
• High blood sugar due to insulin resistance or diabetes  

Some of these risk factors—such as obesity, high blood pressure, and high blood sugar—tend to occur together. When they do, it's called metabolic syndrome.  In general, a person who has metabolic syndrome is twice as likely to develop heart disease and five times as likely to develop diabetes as someone who doesn't have metabolic syndrome.   For more information about the risk factors that are part of metabolic syndrome, go to the Health Topics Metabolic Syndrome article.

Risk Factors You Can't Control

Risk factors that you can't control include:

• Age. The risk of heart disease increases for men after age 45 and for women after age 55 (or after menopause).
• Family history of early heart disease. Your risk increases if your father or a brother was diagnosed with heart disease before 55 years of age, or if your mother or a sister was diagnosed with heart disease before 65 years of age.
• Preeclampsia (pre-e-KLAMP-se-ah). This condition can develop during pregnancy. The two main signs of preeclampsia are a rise in blood pressure and excess protein in the urine. Preeclampsia is linked to an increased lifetime risk of heart disease, including CHD, heart attack, heart failure, and high blood pressure.

What Are the Signs and Symptoms of a Heart Attack?

Not all heart attacks begin with the sudden, crushing chest pain that often is shown on TV or in the movies. In one study, for example, one-third of the patients who had heart attacks had no chest pain. These patients were more likely to be older, female, or diabetic.

The warning signs and symptoms of a heart attack aren't the same for everyone. Many heart attacks start slowly as mild pain or discomfort. Some people don't have symptoms at all. Heart attacks that occur without any symptoms or very mild symptoms are called silent heart attacks.

Chest Pain or Discomfort

The most common heart attack symptom is chest pain or discomfort. This includes new chest pain or discomfort or a change in the pattern of existing chest pain or discomfort.

Most heart attacks involve discomfort in the center or left side of the chest that often lasts for more than a few minutes or goes away and comes back. The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain. The feeling can be mild or severe.

Heart attack pain sometimes feels like indigestion or heartburn.

The symptoms of angina (an-JI-nuh or AN-juh-nuh) can be similar to the symptoms of a heart attack. Angina is chest pain that occurs in people who have coronary heart disease, usually when they're active. Angina pain usually lasts for only a few minutes and goes away with rest.

Chest pain or discomfort that doesn't go away or changes from its usual pattern (for example, occurs more often or while you're resting) can be a sign of a heart attack.

All chest pain should be checked by a doctor.

Other Common Signs and Symptoms

Other common signs and symptoms of a heart attack include new onset of:

• Upper body discomfort in one or both arms, the back, neck, jaw, or upper part of the stomach
• Shortness of breath, which may occur with or before chest discomfort
• Nausea (feeling sick to your stomach), vomiting, light-headedness or sudden dizziness, or breaking out in a cold sweat
• Sleep problems, fatigue (tiredness), or lack of energy

Not everyone having a heart attack has typical symptoms. If you've already had a heart attack, your symptoms may not be the same for another one. However, some people may have a pattern of symptoms that recur.  The more signs and symptoms you have, the more likely it is that you're having a heart attack.

 

Act Fast!

The signs and symptoms of a heart attack can develop suddenly. However, they also can develop slowly—sometimes within hours, days, or weeks of a heart attack.

Know the warning signs of a heart attack so you can act fast to get treatment for yourself or someone else. The sooner you get emergency help, the less damage your heart will sustain.

Call 9–1–1 for help right away if you think you or someone else may be having a heart attack. You also should call for help if your chest pain doesn't go away as it usually does when you take medicine prescribed for angina.

Do not drive to the hospital or let someone else drive you. Call an ambulance so that medical personnel can begin life-saving treatment on the way to the emergency room.


For references, visit Free E-Books on Heart Disease.