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
-
Heparin Therapy
-
Aspirin
-
Beta-Blockers
-
Nitroglycerin
-
IIb/IIIa Inhibitors
-
Primary PTCA
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®).
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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