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Overview
The heart is a complex, highly specialized muscle
that contracts approximately 70 times each minute
to pump blood to the head, arms, chest, abdomen,
and legs. This pumping action requires oxygen,
which is carried in the blood by specialized red
blood cells. Three blood vessels, called the
coronary arteries, supply the heart with blood
and oxygen. Over time, plaques made of cholesterol
and other substances can develop in these arteries
and partially block the flow of blood.
Occasionally, the surface of one of these plaques
can burst or rupture. When this happens, a blood
clot may form on top of the plaque, further
blocking blood flow in the artery.
If a blood clot becomes large enough, it can
completely block the flow of blood through the
coronary artery. This makes the heart muscle
ischemic, meaning it is not receiving enough
oxygen to survive. Ischemia of the heart muscle
can produce chest pains and other related
symptoms. If the muscle in the heart is
deprived of oxygen for 30 minutes or more, it
begins to die. The longer the blockage
deprives the heart muscle of blood-borne oxygen,
the more heart muscle dies. This complete blockage
of a coronary artery leading to death of the heart
muscle is called a heart attack.
Signs and Symptoms
Heart attacks are experienced in different ways. The classic
description of heart attack pain is an intense
ache in the chest, often centered in the left
side of the chest. The pain may radiate outward
into the neck, jaw, back, or arms. Instead
of pain, some people experience a tightness or
pressure in the chest, often describing the
sensation as feeling like "an elephant was sitting
on" their chest. Other symptoms that can accompany
a heart attack include indigestion, nausea,
shortness of breath, intense sweating, or
clamminess.
Because symptoms can vary, it is important to be aware that not
everyone experiences the classic severe chest pain
of a heart attack; some heart attack victims may
experience one or more symptoms. When any of these
symptoms persist longer than approximately 30
minutes, one should assume that they are having a
heart attack.
About one-quarter of all heart attacks occur without producing any
identifiable symptoms. These so-called "silent"
heart attacks may only be discovered incidentally
by examination of an electrocardiogram (EKG) or by
other heart test.
What to Do When Experiencing a Heart Attack
If you think you are having a heart attack,
seek medical attention immediately. There are
two critical reasons to do so.
First, excellent medications and treatments are available that can
help dissolve a blood clot and open a blocked
coronary artery, restoring normal blood and oxygen
to the heart muscle. Less irreparable damage is
done to the heart muscle if these therapies are
initiated promptly.
Second, the heart becomes predisposed to developing irregular heart
rhythms during a heart attack. The most serious of
these arrhythmias are ventricular tachycardia and
ventricular fibrillation, in which the heart
muscle no longer contracts in a regular,
coordinated fashion. Instead, it quivers in place,
becoming incapable of pumping blood to the organs
of the body, including the brain. In these cases,
brain damage and death can occur within minutes.
For this reason, it is best to call 911 and summon
paramedics who can treat these abnormal heart
rhythms if they occur.
Initial Treatment
The goals of intitial treatment are to minimize
damage by restoring blood flow to the heart muscle
and to determine the
amount of damage done
to the heart muscle.
Intensive research over the last 20 or more years
has demonstrated that the prompt initiation of
certain therapies can decrease damage from a heart
attack and increase the chance of survival. These
include:
Thrombolytic Therapy
Several new "clot-busting drugs," collectively
known as "thrombolytic agents," can help dissolve
blood clots and prevent heart damage. These drugs
go by the names r-PA, t-PA, tnk-PA and
streptokinase. Although clot-busting drugs work
best when administered within the first several
hours of a heart attack, they still have some
benefit if administered up to 12 hours after the
onset of heart attack symptoms. Not all heart
attacks can be treated with these medications.
Whether a heart attack should be treated with one
of these drugs can be determined primarily from
information obtainable with an electrocardiogram.
Although these medications carry a small risk of
bleeding — including bleeding into the brain,
causing a stroke — their potential benefits
usually outweigh the risk.
Heparin Therapy
Heparin is a substance used to "thin-out the
blood" and to help prevent further blood clot
formation. It may be particularly useful in
patients who experience intermittent blood clot
formation within a coronary artery. The older form
of heparin, called unfractionated heparin, is
usually administered via a continuous intravenous
infusion, and frequent blood tests need to be
performed to monitor how "thinned out" the heparin
is making the blood.
Newer heparin preparations, called low molecular
weight heparins, have the advantage of being
suitable for administration via injection under
the skin, usually in the abdomen twice a day,
making it less necessary to monitor how
"thinned-out" the blood becomes. In addition to
these practical concerns, several studies suggest
that certain low molecular weight heparins are
superior to the older unfractionated medication in
preventing further adverse events such as
recurrent heart attack or death. These medications
include enoxaparin (Lovenox®), dalteparin (Fragmin®),
and nadroparin (Fraxiparin®).
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Aspirin
Incredible as it may seem, simply taking an
aspirin at the time of a heart attack and then
each day thereafter can decrease the chances of
dying from the heart attack by almost 25%. Blood
clots are composed mostly of platelets,
microscopic particles that circulate in the
bloodstream. These can "stick" to a ruptured
plaque and to each other. Aspirin makes platelets
less "sticky," thereby decreasing the chances of
further blood clot formation.
Beta-Blockers
These are a class of drugs that act to reduce
strain on the heart and, thus its need for oxygen,
by slowing the rate at which the heart beats and
decreasing the strength of the heart's
contractions. Studies have shown that treating a
heart attack with beta-blockers can decrease the
chances of recurrent chest pains, recurrent heart
attack, and death. These agents may be given
intravenously at first and, subsequently, orally.
Commonly used beta blockers include metoprolol (Lopressor®,
Toprol XL®) and atenolol (Atenolol®).
Studies have shown the use of beta-blockers during
and after a heart attack can decrease the chances
of future adverse events, such as recurrent heart
attack and death. Therefore, all patients without
contraindications to beta blocker therapy should
receive such therapy indefinitely. Heart attack
patients who are not being treated with a
beta-blocker should discuss this with the doctor.
Nitroglycerin
Nitroglycerin is a chemical that acts by dilating
or opening up the coronary arteries and the body's
veins. This has the potential to increase blood
flow to the heart, especially the area receiving
insufficient blood flow. Nitroglycerin can be
administered in many ways. A small nitroglycerin
pill can be placed under the tongue, where it
quickly dissolves and is absorbed into the
bloodstream. Nitroglycerin also can be
administered via a continuous intravenous
infusion; placed on the skin in the form of a
cream or patch, where it is slowly absorbed; or
taken in the form of short- or long-acting nitrate
pills. Isosorbide dinitrate (Isordil®) is usually
taken three times a day; isosorbide mononitrate (Ismo®,
Imdur®) is taken either twice a day (Ismo) or once
daily (Imdur).
Because nitroglycerin dilates not only the
coronary arteries but other blood vessels as well,
its vasodilating effects on the blood vessels in
the head can sometimes cause headaches. In some
cases, the headaches are so severe that patients
find they cannot tolerate nitroglycerin therapy.
IIb/IIIa Inhibitors
Pronounced "two-bee-three-aye inhibitors," this
new class of drugs works like super-potent aspirin
therapy. While aspirin can make platelets somewhat
less "sticky," the IIb/IIIa inhibitors can almost
completely prevent platelets from sticking
together and forming blood clots. In addition,
these drugs seem to help dissolve existing blood
clots. Studies have now shown that treatment with
these agents can decrease the chances of recurrent
heart attack or death. Currently available II/IIIa
inhibitors include eptifibatide (Integrelin®),
tirofiban (Aggrastat®), and abciximab (ReoPro®).
Primary PTCA
Instead of being treated with a clot-busting
thrombolytic agent, some heart attack patients may
be taken directly to a cardiac catheterization
laboratory. There, coronary angiography is
performed to take pictures of the heart's arteries
and identify the blocked artery. Special
ultra-thin wires, tiny balloons, and small metal
spring-like devices called stents may then be used
to stretch open the blocked artery. This process
is called "primary PTCA" (see coronary
angioplasty).
Sexual Relations After a Heart Attack
People who have had a heart attack are often
concerned about having sexual relations. Many
worry they may not be healthy enough; they are
concerned that sexual activity will put too much
strain on their heart or lead to another heart
attack. Their partners also worry about these
issues, often more so than the patient. As a
result of these concerns, many couples are
understandably reluctant to resume sexual
activity.
Most people are indeed able to resume sexual
relations at some point after a heart attack. The
strain on one's heart during sexual intercourse is
about the same as the strain from walking up two
flights of stairs. Thus, most people who can do
this should be able to resume sexual activities.
However, specific recommendations as to when one
can resume sexual relations depend on a number of
factors, including the severity of the heart
attack and the amount of residual heart function.
Your doctor should factor these considerations
into his or her recommendations. Doctors rarely
discuss these issues spontaneously with heart
attack patients and their spouses, so you may want
to question your doctor specifically about this
issue.
Two final notes on this subject: Some men and
women become depressed after a heart attack, which
may interfere both with sexual drive and
performance. Additionally, the class of
medications known as beta blockers, used in the
treatment of patients with a heart attack, can
sometimes interfere with the ability to achieve an
erection. However, many other factors can
interfere with the ability to achieve an erection
and abruptly stopping beta-blocker medication is
dangerous. Before you discontinue using this type
of medication, you should talk to your doctor.
Long-Term Therapy
Long-term goals after a heart attack primarily
consist of utilizing medications that facilitate
heart healing and make it easier for the heart to
pump blood and taking steps that decrease the
chances of future heart attacks.
Cardiac medications
that have been shown to decrease the chance of
future heart attacks, and which should be standard
therapy for most patients, include aspirin and
beta blockers. Information is emerging that
suggests long-term use of ACE inhibitors also may
decrease the chance of a future heart attack.
Cholesterol reduction therapy
has been proven to decrease both the chance of
future heart attacks and strokes and the need for
angioplasty or bypass surgery. The primary goal of
therapy is to reduce the level of "bad" (LDL) to
less than 100 mg/dL. Medications proven to be
highly effective in achieving this are known as
statins. They include atorvastatin (Lipitor®),
cerivastatin (Baycol®), fluvastatin (Lescol®),
lovastatin (Mevacor®), pravastatin (Pravachol®),
and simvastatin (Zocor®). These medications
dramatically lower LDL cholesterol levels and are
well tolerated; rare cause side effects include
principally inflammation of the liver and muscle
pain and inflammation. Along with medical therapy,
individuals also need to adopt a diet lower in
cholesterol.
Smoking cessation
can dramatically decrease the risk of heart
attack. Within one year of quitting smoking, the
chances of having a heart attack decrease by about
50%; within 5 to 10 years of quitting, the risk of
having a heart attack becomes the same as that for
anyone the same age who has never smoked. There is
no "best" way to stop smoking. Some people find
they are able to quit by going "cold turkey."
Others need help from support groups, behavior
modification, relaxation techniques, hypnosis, or
acupuncture. One recent study suggests that the
combination of bupropion, an oral medication (Zyban®),
plus a nicotine patch helps some individuals stop
smoking.
Persons who have inactive, sedentary lifestyles
are more likely to develop coronary artery disease
than those who are physically active or exercise
regularly. Regular exercise can improve levels of
"good" (HDL) cholesterol in the blood, may help
control some types of diabetes, lead to modest
reductions in blood pressure, and even reduce the
chance of having a heart attack in the future. If
one has already had a heart attack, he or she
should be sure to consult a physician for help in
devising an exercise program before beginning to
exercise. The doctor may be able to refer the
patient to one of the organized cardiac
rehabilitation programs available at many
hospitals and community centers.
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