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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
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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.
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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
- 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
- Heart disease diagnosed in mother or sister before
- Having a personal history of CAD
- A previous heart attack
- A surgical procedure (angioplasty, heart bypass)
to increase blood flow to your heart.
Risk factors that you can change include:
- High blood pressure
- High blood cholesterol
- Being physically inactive
- Diabetes (high blood sugar) .
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
- 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
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
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.
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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 chambers, collect
blood samples from the heart, and examine the arteries
of the heart by x-ray.
- Coronary angiography. This test is usually performed
along with cardiac catheterization. A dye that can be seen
using x-ray is injected through the catheter into the coronary
arteries. Your doctor can see the flow of blood through
the heart and see where there are blockages.
A heart attack is a medical emergency. Delaying treatment
can mean lasting damage to your heart or even death. The
sooner treatment begins, the better your chances of recovering.
Your treatment may begin in the ambulance or in the emergency
room and continue in a special area called a coronary care
unit or CCU.
In the Hospital
If you are having a heart attack, doctors will:
- Work quickly to restore blood flow to the heart
- Continuously monitor your vital signs to detect and
Restoring blood flow to the heart is vital to prevent or
limit damage to the heart muscle and to prevent another
heart attack. The main treatments are the use of thrombolytic
("clot-busting") drugs and procedures such as angioplasty.
- Thrombolytic drugs ("clot-busters") are used to dissolve
blood clots that are blocking blood flow to the heart.
When given soon after a heart attack begins, these
drugs can limit or prevent permanent damage to the
heart. To be most effective, they need to be given
within 1 hour after of the start of heart attack symptoms.
- Angioplasty procedures are used to open blocked or
narrowed coronary arteries. A stent, which is a tiny
metal mesh tube, may be placed in the artery to help
keep it open.
- Coronary artery bypass surgery uses arteries or veins
from other areas in your body to bypass your blocked
The CCU is specially equipped with monitors that continuously
measure your vital signs. Those that can show signs of
- EKG, which detects any heart rhythm (arrhythmia)
or functional problems
- Blood pressure
- Pulse oximetry, which measures the amount of oxygen
in the blood and provides an early warning sign of
a low level of oxygen in the blood.
used in treating heart attacks include:
- Beta blockers to decrease the workload on your heart
by slowing your heart rate. This makes your heart beat
with less force and lowers your blood pressure. Some
beta blockers are also used to relieve angina (chest
pain) and in heart attack patients to help prevent
additional heart attacks. They are also used to correct
- Angiotensin-converting enzyme (ACE) inhibitors to
lower blood pressure and reduce the strain on your
heart. They are used in some patients after a heart
attack to increase survival rate and help slow down
further weakening of the heart.
- Nitrates, such as nitroglycerin, to relax blood vessels
and stop chest pain.
- Anticoagulants (an-ty-ko-AG-u-lants) to thin the
blood and prevent clots from forming in your arteries.
- Antiplatelet (an-ty-PLAYT-lit) medications (such
as aspirin and clopidigrel) to stop platelets from
clumping together to form clots. These medications
are given to people who have had a heart attack, have
angina, or who experience angina after angioplasty.
- Glycoprotein IIb-IIIa inhibitors, which are potent
antiplatelet medicines given intravenously to prevent
clots from forming in your arteries.
- Medicines to relieve pain and anxiety.
- Medicines to treat arrhythmias (irregular heart rhythms),
which often occur during a heart attack.
- Oxygen therapy.
The length of your hospital stay after a heart attack depends
on your condition and response to treatment. Most people
spend several days in the hospital after a heart attack.
While in the hospital, your heart will be monitored, and
you will receive needed medications. You will probably
have further testing, and you will be treated for any complications
While you are still in the hospital or after you go home
after your heart attack, your doctor may order other tests,
Cardiac Rehabilitation (Rehab)
- Echocardiogram. In this test, ultrasound is
used to make an image of your heart that can be seen
on a video monitor. It shows how well the heart is
filling with blood and pumping it to the rest of the
- Exercise stress test. This test shows how
well your heart pumps at higher workloads when it needs
more oxygen. EKG and blood pressure readings are taken
before, during, and after exercise to see how your
heart responds to exercise. The first EKG and blood
pressure reading are done to get a baseline. Readings
are then taken while you walk on an exercise treadmill
or pedal a stationary bicycle. The test continues until
you reach a heart rate set by your doctor. The exercise
part is stopped if chest pain or a very sharp rise
in blood pressure occurs. Monitoring continues for
10 to 15 minutes after exercise or until your heart
rate returns to baseline.
Your doctor may prescribe cardiac rehabilitation (rehab)
to help you recover from a heart attack and help prevent
another heart attack. Almost everyone who has survived
a heart attack can benefit from rehab.
The cardiac rehab team may include:
- Your family doctor
- A heart specialist
- A surgeon
- Exercise specialists
- Physical therapists and occupational therapists
- Psychologists or other behavior therapists.
Rehab has two parts:
- Exercise training to help you learn how to
exercise safely, strengthen your muscles, and improve
your stamina. Your exercise plan will be based on your
individual ability, needs, and interests.
- Education, counseling, and training to help
you understand your heart condition and find ways to
reduce your risk of future heart problems. The cardiac
rehab team will help you learn how to cope with the
stress of adjusting to a new lifestyle and to deal
with your fears about the future.
After You Leave the Hospital
After a heart attack, your treatment may include cardiac
rehab in the first weeks or months, checkups and tests,
lifestyle changes, and medications. You will need to see
your doctor for checkups and tests to see how your heart
is doing. Your doctor will most likely recommend lifestyle
changes, such as quitting smoking, losing weight, changing
your diet, or increasing your physical activity.
After a heart attack, most people take daily medications.
These may include:
- Medicines that lower your cholesterol or your blood
- Other medicines to help reduce your heart's workload.
Always take medications as your doctor directs.
Most heart attacks are caused by coronary artery disease (CAD). You can help
prevent a heart attack by knowing about your risk factors for CAD and heart
attack and taking action to lower your risks.
You can lower your risk of having a heart attack, even
if you have already had a heart attack or are told that
your chances of having a heart attack are high.
To prevent a heart attack, you will most likely need to
make lifestyle changes. You may also need to get treatment
for conditions that raise your risk.
Make Lifestyle Changes
You can lower your risk for CAD and a heart attack by making
healthy lifestyle choices:
Treat Related Conditions
- Eat a healthy diet to prevent or reduce high blood
pressure and high blood cholesterol, and maintain a
- If you smoke, quit
- Exercise as directed by your doctor
- Lose weight if you are overweight or obese
In addition to making lifestyle changes, you can help prevent
heart attacks by treating conditions you have that make
a heart attack more likely:
Prevent a Second Heart Attack
- High blood cholesterol. If you have high cholesterol,
follow your doctor's advice about lowering your cholesterol.
Take medications to lower your cholesterol as directed.
- High blood pressure. If you have high blood
pressure, follow your doctor's advice about keeping
your blood pressure under control. Take blood pressure
medications as directed.
- High blood sugar (diabetes). If you have diabetes,
follow your doctor's advice about keeping your blood
sugar levels under control. Take medications as directed.
If you have already had a heart attack, it is very important
to follow your doctor's advice to prevent a second heart
- Make lifestyle changes as directed
- Take your medications as directed
- Follow any other treatment recommended by your doctor,
such as cardiac rehabilitation.
By taking these steps, you can prevent or reduce the chance
of another heart attack and related complications, such
as heart failure.
Make sure that you have an emergency action plan in case you have signs of
a second heart attack. Talk to your doctor about making your plan, and talk
with your family about it. The plan should include:
- The signs and symptoms of a heart attack
- Instructions for the prompt use of aspirin and nitroglycerin
- How to access emergency medical services in your community (most people
- The location of the nearest hospital that offers 24-hour emergency
Remember, the symptoms of a second heart attack may not be the same as those
of a first heart attack. If in doubt, call 9-1-1.
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