Having A Heart Attack

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A heart attack occurs when the supply of blood and oxygen to an area of heart
muscle is blocked, usually by a clot in a coronary artery. Often, this blockage
leads to arrhythmias (irregular heartbeat or rhythm) that cause a severe
decrease in the pumping function of the heart and may bring about sudden death.
If the blockage is not treated within a few hours, the affected heart muscle
will die and be replaced by scar tissue.

A heart attack is a
life-threatening event. Everyone should know the warning signs of a heart attack
and how to get emergency help. Many people suffer permanent damage to their
hearts or die because they do not get help immediately.

Each year, more
than a million persons in the U.S. have a heart attack and about half (515,000)
of them die. About one-half of those who die do so within 1 hour of the start
of symptoms and before reaching the hospital.

Emergency personnel
can often stop arrhythmias with emergency CPR (cardiopulmonary resuscitation),
defibrillation (electrical shock), and prompt advanced cardiac life support
procedures. If care is sought soon enough, blood flow in the blocked artery can
be restored in time to prevent permanent damage to the heart. Yet, most people
do not seek medical care for 2 hours or more after symptoms begin. Many people
wait 12 hours or longer.

A heart attack is an emergency. Call 9-1-1
if you think you (or someone else) may be having a heart attack. Prompt
treatment of a heart attack can help prevent or limit lasting damage to the
heart and can prevent sudden death.

Other Names for Heart
Attack

Myocardial infarction or MI
Acute myocardial infarction or AMI
Acute coronary syndrome
Coronary thrombosis
Coronary occlusionWhat Causes a Heart Attack?
Most heart attacks
are caused by a blood clot that blocks one of the coronary arteries (the blood
vessels that bring blood and oxygen to the heart muscle). When blood cannot
reach part of your heart, that area starves for oxygen. If the blockage
continues long enough, cells in the affected area die.

Coronary Artery
Disease (CAD) is the most common underlying cause of a heart attack. CAD is the
hardening and narrowing of the coronary arteries by the buildup of plaque in the
inside walls (atherosclerosis). Over time, plaque buildup in the coronary
arteries can:
- Narrow the arteries so that less blood flows to the heart muscle
- Completely block the arteries and the flow of blood
- Cause blood clots to form and block the arteries.
A
less common cause of heart attacks is a severe spasm (tightening) of the
coronary artery that cuts off blood flow to the heart. These spasms can occur in
persons with or without CAD. Artery spasm can sometimes be caused by:
- Taking certain drugs, such as cocaine
- Emotional stress
- Exposure to cold
- Cigarette smoking.
What Makes a Heart Attack More
Likely?

Certain factors make it more likely that you will develop
CAD and have a heart attack. These are called risk factors. Risk factors
you cannot change include:
- Your age
  - Men: over age 45
  - Women: over age 55
- Having a family history of early heart disease
  - Heart disease diagnosed in father or brother before age 55
  - Heart disease diagnosed in mother or sister before age 65
- Having a personal history of CAD
  - Angina
  - A previous heart attack
  - A surgical procedure (angioplasty, heart bypass) to increase blood flow to
    your heart.
Risk factors that you can change include:
- Smoking
- High blood pressure
- High blood cholesterol
- Obesity
- Being physically inactive
- Diabetes (high blood sugar) .
What Are the Signs and
Symptoms of a Heart Attack?

The warning signs and symptoms of a
heart attack can include:
- Chest discomfort. Most heart attacks involve discomfort in the center
  of the chest that lasts for more than a few minutes, or goes away and comes
  back. The discomfort can feel like uncomfortable pressure, squeezing, fullness,
  or pain. Heart attack pain can sometimes feel like indigestion or heartburn.
- Discomfort in other areas of the upper body. Can include pain,
  discomfort, or numbness in one or both arms, the back, neck, jaw, or stomach.
- Shortness of breath. Often comes along with chest discomfort. But it
  also can occur before chest discomfort.
- Other symptoms. May include breaking out in a cold sweat, having
  nausea and vomiting, or feeling light-headed or dizzy.
Signs and
symptoms vary from person to person. In fact, if you have a second heart attack,
your symptoms may not be the same as for the first heart attack. Some people
have no symptoms. This is called a “silent” heart attack.

The symptoms
of angina can be similar to those of a heart attack. If you have angina and
notice a change or a worsening of your symptoms, talk with your doctor right
away.

Know the warning signs of a heart attack so you can act fast to
get treatment. Many heart attack victims wait 2 hours or more after their
symptoms begin before they seek medical help. This delay can result in death or
lasting heart damage.

If you think you may be having a heart attack,
or if your angina pain does not go away as usual when you take your angina
medicine as directed, call 9-1-1 for help. You can begin to receive life-saving
treatment in the ambulance on the way to an emergency room.

How
is a Heart Attack Diagnosed?

Diagnosis (and treatment) of a heart
attack can begin when emergency medical personnel arrive after you call 9-1-1.
Don’t put off calling 9-1-1 because you are not sure that you are having a heart
attack.

At the hospital emergency room, doctors will work fast to find
out if you are having or have had a heart attack. They will consider your
symptoms, medical and family history, and test results. Initial tests will be
quickly followed by treatment if you are having a heart attack.

Tests
used include:
- Electrocardiogram (ECG or EKG). This test is used to measure the rate
  and regularity of your heartbeat. A 12-lead EKG is used in diagnosing a heart
  attack.
- Blood tests. When cells in the heart die, they release enzymes into
  the blood. They are called markers or biomarkers. Measuring the amount of these
  markers in the blood can show how much damage was done to your heart. These
  tests are often repeated at intervals to check for changes. The specific blood
  tests are:
  - Troponin test. This test checks the troponin levels in the blood. It
    is considered the most accurate blood test to see if a heart attack has occurred
    and how much damage was done to the heart.
  - CK or CK-MB test. These tests check for the amount of the different
    forms of creatine kinase in the blood.
  - Myoglobin test. This test checks for the presence of myoglobin in the
    blood. Myoglobin is released when the heart or other muscle is injured.
- Nuclear heart scan. This test uses radioactive tracers (technetium or
  thallium) to outline heart chambers and major blood vessels leading to and from
  the heart. A nuclear heart scan shows any damage to your heart muscle.
- Cardiac catheterization. A thin flexible tube (catheter) is passed
  through an artery in the groin or arm to reach the coronary arteries. Your
  doctor can determine pressure and blood flow in the heart’s chamber